Vocab v30

hermetic

(of a seal or closure) complete and airtight. airtight and watertight

Any sufficiently advanced technology is indistinguishable from magic.

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Dogs can detect epileptic seizures up to 45 minutes before they occur. That's thanks to their incredible noses, new research shows. A canine nose can smell odor molecules in the parts per trillion, including those the human body releases during a seizure

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In many species of jellyfish, the rhopalia include ocelli, light-sensitive organs able to tell light from dark. These are generally pigment spot ocelli, which have some of their cells pigmented. The rhopalia are suspended on stalks with heavy crystals at one end, acting like gyroscopes to orient the eyes skyward. Certain jellyfish look upward at the mangrove canopy while making a daily migration from mangrove swamps into the open lagoon, where they feed, and back again. Box jellyfish have more advanced vision than the other groups. Each individual has 24 eyes, two of which are capable of seeing colour, and four parallel information processing areas that act in competition, supposedly making them one of the few kinds of animal to have a 360-degree view of its environment.

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megabyte

1 million bytes or 8 million bits

Why are lithium ion batteries preferred over acid electrolyte batteries?

1) Weight: Lithium-ion batteries are one-third the weight of lead acid batteries. 2) Efficiency: Lithium-ion batteries are nearly 100% sitting at about 80-90% efficient in both charge and discharge, allowing for the same amp hours both in and out. Lead acid batteries' inefficiency leads to a loss of 15 amps while charging and rapid discharging drops voltage quickly and reduces the batteries' capacity. 3) Discharge: Lithium-ion batteries are discharged close to 100% versus less than 80% for lead acid. Most lead acid batteries do not recommend more than 50% depth of discharge. 4) Cycle Life: Rechargeable lithium-ion batteries cycle 500 times (cycles) more compared to just 400-500 cycles in lead acid. Cycle life is greatly affected by higher levels of discharge in lead acid, versus only slightly affected in lithium-ion batteries. 5) Operational use: Lithium-ion batteries maintain their operational use throughout the entire discharge cycle. This allows for greater and longer-lasting efficiency of electrical components. Lead acid operational use drops consistently throughout the discharge cycle. 6) Cost: Despite the higher upfront cost of lithium-ion batteries, the true cost of ownership is far less than lead acid when considering life span and performance. 7) Environmental Impact: Lithium-ion batteries are a much cleaner technology and are safer for the environment.

What are 2 bits called?

2 bits = crumb 4 bits = nibble 8 bits = byte

byte

8 bits

Nomex

A Nomex hood is a common piece of racing and firefighting equipment. It is placed on the head on top of a firefighter's face mask. The hood protects the portions of the head not covered by the helmet and face mask from the intense heat of the fire. Nomex Paper is used in electrical laminates such as circuit boards and transformer cores as well as fireproof honeycomb structures where it is saturated with a phenolic resin. Honeycomb structures such as these, as well as mylar-Nomex laminates, are used extensively in aircraft construction. Firefighting, military aviation, and vehicle racing industries use Nomex to create clothing and equipment that can withstand intense heat.

static equilibrium

A condition where there are no net external forces acting upon a particle or rigid body and the body remains at rest or continues at a constant velocity. In classical mechanics, a particle is in mechanical equilibrium if the net force on that particle is zero. By extension, a physical system made up of many parts is in mechanical equilibrium if the net force on each of its individual parts is zero.

Biodiesel

A diesel substitute produced by extracting and chemically altering oil from plants Biodiesel refers to a vegetable oil- or animal fat-based diesel fuel consisting of long-chain alkyl (methyl, ethyl, or propyl) esters. Biodiesel is typically made by chemically reacting lipids (e.g., vegetable oil, soybean oil, animal fat (tallow) with an alcohol producing fatty acid esters. Biodiesel is a drop-in biofuel and thus meant to be used in standard diesel engines and is thus distinct from the vegetable and waste oils used to fuel converted diesel engines. Biodiesel can be used alone, or blended with petrodiesel in any proportions. Biodiesel blends can also be used as heating oil. The National Biodiesel Board (USA) defines "biodiesel" as a mono-alkyl ester.

battery discharge curve

A flat discharge curve simplifies the design of the application in which the battery is used since the supply voltage stays reasonably constant throughout the discharge cycle. When you charge your phone, the AC supply needs to be rectified before it can reverse the oxidation-reduction reaction in your secondary battery.

HAZOP

A hazard and operability study (HAZOP) is a structured and systematic examination of a complex planned or existing process or operation in order to identify and evaluate problems that may represent risks to personnel or equipment.

Loaded dice

A loaded, weighted, cheat, or crooked die is one that has been tampered with so that it will land with a specific side facing upwards more or less often than a fair die would. Some people just are no longer willing to shrug helplessly and accept a life where the dice are loaded against them.

Biogas

A mixture of methane and carbon dioxide produced by bacterial degradation of organic matter and used as a fuel. Biogas is a type of biofuel that is naturally produced from the decomposition of organic waste. When organic matter, such as food scraps and animal waste, break down in an anaerobic environment (an environment absence of oxygen) they release a blend of gases, primarily methane and carbon dioxide.

Underwriters Laboratories (UL)

A nonprofit agency that tests and certifies electrical equipment in the United States. Underwriters Laboratories (UL) is the largest and best known independent, not-for-profit testing laboratory in the world. Based in Northwood, Illinois, UL conducts safety and quality tests on a broad range of products, from fire doors to CCTV cameras.

pasteurization

A process of heating food to a temperature that is high enough to kill most harmful bacteria without changing the taste of the food. Pasteurization or pasteurisation is a process in which water and certain packaged and non-packaged foods (such as milk and fruit juice) are treated with mild heat, usually to less than 100 °C (212 °F), to eliminate pathogens and extend shelf life. The process is intended to destroy or deactivate organisms and enzymes that contribute to spoilage or risk of disease, including vegetative bacteria, but not bacterial spores. Since pasteurization is not sterilization, and does not kill spores, a second "double" pasteurization will extend the quality by killing spores that have germinated. The process was named after the French scientist Louis Pasteur, whose research in the 1880s demonstrated that thermal processing would inactivate unwanted microorganisms in wine. Spoilage enzymes are also inactivated during pasteurization. Today, pasteurization is used widely in the dairy industry and other food processing industries to achieve food preservation and food safety. Most liquid products are heat treated in a continuous system where heat can be applied using a plate heat exchanger and/or the direct or indirect use of hot water and steam. Due to the mild heat, there are minor changes to the nutritional quality and sensory characteristics of the treated foods.[4] Pascalization or high pressure processing (HPP) and pulsed electric field (PEF) are non-thermal processes that are also used to pasteurize foods.

force

A push or pull exerted on an object In science, force is the push or pull on an object with mass that causes it to change velocity (to accelerate). Force represents as a vector, which means it has both magnitude and direction.

Kevlar

A strong synthetic material used in the construction of protective clothing and equipment. Bullet proof vest. Kevlar has many applications, ranging from bicycle tires and racing sails to bulletproof vests, because of its high tensile strength-to-weight ratio; by this measure it is five times stronger than steel.[2] It also is used to make modern marching drumheads that withstand high impact. When used as a woven material, it is suitable for mooring lines and other underwater applications. Kevlar is synthesized in solution from the monomers 1,4-phenylene-diamine (para-phenylenediamine) and terephthaloyl chloride in a condensation reaction yielding hydrochloric acid as a byproduct. The result has liquid-crystalline behavior, and mechanical drawing orients the polymer chains in the fiber's direction. Hexamethylphosphoramide (HMPA) was the solvent initially used for the polymerization, but for safety reasons, DuPont replaced it by a solution of N-methyl-pyrrolidone and calcium chloride. As this process had been patented by Akzo (see above) in the production of Twaron, a patent war ensued.[9]

Polyethylene terephthalate (PET) (Dacron)

A thermoplastic that is used to manufacture food and drink packaging. It is lightweight, usually transparent, although it is also available in a range of colours. Biaxially oriented PET film (often known by one of its trade names, "Mylar") can be aluminized by evaporating a thin film of metal onto it to reduce its permeability, and to make it reflective and opaque (MPET). These properties are useful in many applications, including flexible food packaging and thermal insulation (such as space blankets). Because of its high mechanical strength, PET film is often used in tape applications, such as the carrier for magnetic tape or backing for pressure-sensitive adhesive tapes.

truncated cone

A truncated cone is the result of cutting a cone by a plane parallel to the base and removing the part containing the apex. The height is the line segment that joins the two bases perpendicularly.

Omnidirectional antenna

A type of antenna that issues and receives wireless signals with equal strength and clarity in all directions. This type of antenna is used when many different receivers must be able to pick up the signal, or when the receiver's location is highly mobile. used on satellites

diatoms

A unicellular photosynthetic alga with a unique glassy cell wall containing silica a single-celled alga which has a cell wall of silica. Many kinds are planktonic, and extensive fossil deposits have been found. Diatoms are unicellular eukaryotic microalgae that play important ecological roles on a global scale. Diatoms are responsible for 20% of global carbon fixation and 40% of marine primary productivity. Thus they are major contributors to climate change processes, and form a substantial basis of the marine food web.

Zombie star

A zombie star is a hypothetical result of a Type Iax supernova which leaves behind a remnant star, rather than completely dispersing the stellar mass. Type Iax supernovae are similar to Type Ia, but have a lower ejection velocity and lower luminosity. A star supernovas only to produce another star. Zombie stars like these are rare but not unheard of: another similar cosmic object, called LP 40-365, was spotted back in 2017. The three new zombie stars highlighted in a newly published study seem to have a lot in common with LP 40-365, including their relatively large size but relatively low mass.

electrostatic air filter

Air Commander electrostatic air filters clean the air by using static electricity - a safe, naturally occurring phenomenon. An electrostatic charge is generated by air flowing through a maze of static prone fibers. Airborne particles are attracted and held by the static charge until released by washing

Human Genome Project

An international collaborative effort to map and sequence the DNA of the entire human genome. The Human Genome Project originally aimed to map the nucleotides contained in a human haploid reference genome (more than three billion). The "genome" of any given individual is unique; mapping the "human genome" involved sequencing a small number of individuals and then assembling these together to get a complete sequence for each chromosome. Therefore, the finished human genome is a mosaic, not representing any one individual. More than 3.2 billion base pairs were sequenced

Newton's First Law

An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. An unbalanced force is a force that changes the position, speed or direction of the object to which it is applied. The unbalanced force accelerates the object with the acceleration directly proportional to the size of the force and inversely proportional to the mass of the object.

Braess's paradox

Braess' paradox is the observation that adding one or more roads to a road network can end up impeding overall traffic flow through it. The paradox was postulated in 1968 by German mathematician Dietrich Braess, who noticed that adding a road to a particular congested road traffic network would increase overall journey time. The paradox may have analogies in electrical power grids and biological systems. It has been suggested that in theory, the improvement of a malfunctioning network could be accomplished by removing certain parts of it. The paradox has been used to explain instances of improved traffic flow when existing major roads are closed.

buoyancy

Buoyancy or upthrust, is an upward force exerted by a fluid that opposes the weight of an immersed object. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus the pressure at the bottom of a column of fluid is greater than at the top of the column Buoyancy is caused by differences in pressure acting on opposite sides of an object immersed in a static fluid. The direction of the net force due to the fluid is upward.

carbon neutral energy

Carbon-neutral fuel is energy fuel or energy systems which have no net greenhouse gas emissions or carbon footprint. Carbon-neutral fuel is energy fuel or energy systems which have no net greenhouse gas emissions or carbon footprint. One class is synthetic fuel (including methane, gasoline, diesel fuel, jet fuel or ammonia)[3] produced from renewable, sustainable or nuclear energy used to hydrogenate carbon dioxide directly captured from the air (DAC), recycled from power plant flue exhaust gas or derived from carbonic acid in seawater. Renewable energy sources include wind turbines, solar panels, and hydroelectric power stations. Another type of renewable energy source is biofuel. Such fuels are potentially carbon-neutral because they do not result in a net increase in atmospheric greenhouse gases. To the extent that carbon-neutral fuels displace fossil fuels, or if they are produced from waste carbon or seawater carbonic acid, and their combustion is subject to carbon capture at the flue or exhaust pipe, they result in negative carbon dioxide emission and net carbon dioxide removal from the atmosphere, and thus constitute a form of greenhouse gas remediation. Such power to gas carbon-neutral and carbon-negative fuels can be produced by the electrolysis of water to make hydrogen. Through the Sabatier reaction methane can then be produced which may then be stored to be burned later in power plants (as a synthetic natural gas), transported by pipeline, truck, or tanker ship, or be used in gas to liquids processes such as the Fischer-Tropsch process to make traditional fuels for transportation or heating.

Coagulation filtration

Coagulation/filtration is a process that removes contaminants from water by precipitation. Aluminum salts and ferric (iron) salts are the two most commonly used coagulants in the water treatment industry. ... The hydroxides adsorb arsenic and the resulting solids are filtered out in the pressure filter vessel.

computer vision

Combines hardware and AI software that permit computers to capture, store, and interpret visual images and pictures Techniques to let computers and robots see and understand the world around them. current struggles integrating computer vision with AI. Its hard to train the algorithms to distinguish objects in a 3D space as we would.

CAD

Computer Aided Design Computer-aided design is the use of computers to aid in the creation, modification, analysis, or optimization of a design. CAD software is used to increase the productivity of the designer, improve the quality of design, improve communications through documentation, and to create a database for manufacturing.

CAM

Computer-aided manufacturing (CAM) is an application technology that uses computer software and machinery to facilitate and automate manufacturing processes. CAM is the successor of computer-aided engineering (CAE) and is often used in tandem with computer-aided design (CAD).

feedback control

Control that focuses on the use of information about previous results to correct deviations from the acceptable standard. Likewise; "A Feedback Control System is a system which tends to maintain a prescribed relationship of one system variable to another by comparing functions of these variables and using the difference as a means of control." A control that takes in system variables and adjusts them as such to achieve the set parameter.

Battery dendrites

Dendrites are needle-like growths that appear on the surface of lithium metal, which is used as the anode, or negative electrode, of the battery if the dendrites connect between the anode and cathode, the battery will be short circuited. A dendrite begins when lithium ions start to clump, or "nucleate," on the surface of the anode, forming a particle that signifies the birth of a dendrite. The structure grows slowly as more and more lithium atoms glom on, growing the same way that a stalagmite grows from the floor of a cave Why lithium is good for batteries: First, it is highly reactive because it readily loses its outermost electron, making it easy to get current flowing through a battery. Second, lithium is much lighter than other metals used in batteries, such as lead, which is important for small objects such as phones but also for cars that require many batteries. Third, lithium-ion batteries are rechargeable, because lithium ions and electrons move easily back into negative electrodes.

drug delivery

Drug delivery refers to approaches, formulations, technologies, and systems for transporting a pharmaceutical compound in the body some time based on nanoparticles as needed to safely achieve its desired therapeutic effect.

Why did the Challenger explode?

Failure of pressure seal in aft field joint of right solid rocket motor On January 28, 1986, the Space Shuttle Challenger exploded 73 seconds after liftoff, killing seven crew members and traumatizing a nation. The cause of the disaster was traced to an O-ring, a circular gasket that sealed the right rocket booster.

Newton's Third Law

For every action there is an equal and opposite reaction Formally stated, Newton's third law is: For every action, there is an equal and opposite reaction. The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second object.

Homogenizer

For reducing particle size and evenly suspending liquids Homogenization, process of reducing a substance, such as the fat globules in milk, to extremely small particles and distributing it uniformly throughout a fluid, such as milk. When milk is properly homogenized, the cream will not rise to the top.

Newton's Second Law

Force = mass x acceleration Newton's second law of motion pertains to the behavior of objects for which all existing forces are not balanced. The second law states that the acceleration of an object is dependent upon two variables - the net force acting upon the object and the mass of the object.

flocculation

Formation of flaky masses resulting from precipitation or coming out of a suspension or solution Flocculation, in the field of chemistry, is a process in which colloids come out of suspension in the form of floc or flake, either spontaneously or due to the addition of a clarifying agent. The action differs from precipitation in that, prior to flocculation, colloids are merely suspended in a liquid and not actually dissolved in a solution. In the flocculated system, there is no formation of a cake, since all the flocs are in the suspension. Coagulation and flocculation are important processes in water treatment with coagulation to destabilize particles through chemical reaction between coagulant and colloids, and flocculation to transport the destabilized particles that will cause collisions with floc. Contents

How do hydrogen fuel cells work?

Fuel Cells are not exactly new per say. Welsh Physicist William Grove developed the first crude fuel cells in 1839. The first commercial use of fuel cells was in NASA's space programs to generate power for probes, satellites and space capsules. Since then, fuel cells have been used in many other applications such as primary and backup power for commercial, industrial and residential buildings and in remote or inaccessible areas. The most common type used is the the Proton Exchange Membrane (PEM) where a thin permeable polymeric membrane is used as the electrolyte. The membrane is very small and light and in order to catalyse the reaction, platinum electrodes are used on either side of the membrane. Within the PEM fuel cell unit, hydrogen molecules are supplied at the anode and split in to hydrogen protons and electrons. The protons pass across the polymeric membrane to the cathode while the electrons are pushed round an external circuit in order to produce electricity. Oxygen (in the form of air) is supplied to the cathode and combines with the hydrogen ions to produce water. Fuel cells have two adjacent chambers-the anode side and the cathode side-separated by a membrane. Hydrogen gas enters the anode side where the atoms react with a platinum catalyst and release electrons. That chamber becomes flooded with free electrons and hydrogen protons, or hydrogen atoms stripped of their electrons. The positively charged hydrogen protons pass through the membrane into the cathode side of the fuel cell. The electrons flow out of the anode side to power a load. After running through the system wiring, the electrons re-enter the fuel cell on the cathode side, completing the electrical path. On the cathode side, the hydrogen protons that slipped through the membrane combine with the free electrons and with oxygen molecules to produce pure water. You can envision a fuel cell as a system that borrows electrons from hydrogen, ships them off to do some useful work, such as running the site load, and then grabs them back and partners them with oxygen to form water.

What would happen if you breathe pure oxygen?

If you breathe air with a much higher than normal O2 concentration, the oxygen in the lungs overwhelms the blood's ability to carry it away. The result is that free oxygen binds to the surface proteins of the lungs, interferes with the operation of the central nervous system and also attacks the retina. When you inhale, the alveoli fill with this air. Once in their suits, astronauts breathe pure oxygen for a few hours. Breathing only oxygen gets rid of all the nitrogen in an astronaut's body. If they didn't get rid of the nitrogen, the astronauts might get gas bubbles in their body when they walked in space.

are welds or bolts stronger?

In conclusion, bolted joints have the advantage of cost and simplicity, but there is a loss of structural performance. On the other hand, welded joints are stronger but more expensive and difficult to handle.

Vikings discover steel, kinda.

In early Iron Age Scandinavia, for instance, just before the advent of the Viking Age, smiths discovered a ritual that enabled them to impart the steely strength of their ancestors and animals into their weapons. This was a crucial transformation for Scandinavians; the majority of iron they had access to was bog iron. Bacteria in bogs oxidize trace amounts of iron to gain energy and, in so doing, concentrate the iron, enabling its collection for smithing. However, the resulting iron is impure and soft, which was a big problem for the Scandinavians. Conflicts could easily be decided by the side that had the better equipment, and Iron Age Scandinavia was full of conflict. Incorporating bones into the smithing process did in fact make Scandinavian swords stronger, but it wasn't magic — it was technology. What ancient smiths could not have realized is that they were in fact mixing their bog iron with carbon to make a rudimentary form of steel. Carbon is present in all organic matter, and the same is true for bones. By burning bones in a low-oxygen environment, ancient smiths would have produced bone-coal, much in the same way that burning wood in a low-oxygen environment makes charcoal. Researchers have conducted experiments that recreate the process of forging a sword using bog iron and bone-coal; the carbon from the bones can penetrate up to 3 millimeters deep into bog iron, enough to significantly strengthen the sword. Ultimately this produced the Ulfberht. The famous viking sword.

Shannon-Hartley theorem

In information theory, the Shannon-Hartley theorem tells the maximum rate at which information can be transmitted over a communications channel of a specified bandwidth in the presence of noise. It is an application of the noisy-channel coding theorem to the archetypal case of a continuous-time analog communications channel subject to Gaussian noise. The theorem establishes Shannon's channel capacity for such a communication link, a bound on the maximum amount of error-free information per time unit that can be transmitted with a specified bandwidth in the presence of the noise interference, assuming that the signal power is bounded, and that the Gaussian noise process is characterized by a known power or power spectral density. The law is named after Claude Shannon and Ralph Hartley. Bit transfer rate

What caused the mistake that led to the destruction of the Mars probe?

Mars Probe Lost Due to Simple Math Error. NASA lost its $125-million Mars Climate Orbiter because spacecraft engineers failed to convert from English to metric measurements when exchanging vital data before the craft was launched, space agency officials said Thursday.

microbubbles

Microbubbles are bubbles smaller than one hundredth of a millimetre in diameter, but larger than one micrometre. They have widespread application in industry, life science, and medicine. The composition of the bubble shell and filling material determine important design features such as buoyancy, crush strength, thermal conductivity, and acoustic properties. Microbubbles may be used for drug delivery, biofilm removal, membrane cleaning/biofilm control and water/waste water treatment purposes. They are used in medical diagnostics as a contrast agent for ultrasound imaging.[1] The gas-filled, e.g. air or perfluorocarbon, microbubbles oscillate and vibrate when a sonic energy field is applied and may reflect ultrasound waves. This distinguishes the microbubbles from surrounding tissues. In practice, because gas bubbles in liquid lack stability and would therefore quickly dissolve, microbubbles must be encapsulated with a solid shell. The shell is made from either a lipid or a protein such as Optison microbubbles which consist of perfluoropropane gas encapsulated by a serum albumin shell. Microbubbles may be used for drug delivery,[2] biofilm removal,[3] membrane cleaning[4]/biofilm control and water/waste water treatment purposes.[5] They are also produced by the movement of a ship's hull through water, creating a bubble layer; this may interfere with the use of sonar because of the tendency of the layer to absorb or reflect sound waves.[6] Future: Could be released into bloodstream, filled with necessary gases, and then popped via a UV light to only release the chemicals in a discrete area.

is information stored in neurons or synapses?

Most neuroscientists will tell you that long-term memories are stored in the brain in the form of synapses, the connections between neurons. On this view, memory formation occurs when synaptic connections are strengthened, or entirely new synapses are formed

Statics and Dynamics

Name the two main areas in which mechanics can be divided. Informally, dynamics is the study of forces and motion. ... In contrast, statics is the study of forces without motion; or more formally, the branch of mechanics that deals with forces in the absence of changes in motion. Dynamics implies change. Statics implies changelessness.

Nanoparticle drug delivery

Nanoparticle drug delivery systems are engineered technologies that use nanoparticles for the targeted delivery and controlled release of therapeutic agents. The modern form of a drug delivery system should minimize side-effects and reduce both dosage and dosage frequency. Use nanomagnetic robots that navigate based off the iron in hemoglobin in the blood

Colors change at the nano level

Nanoscale gold particles are not the yellow color with which we are familiar; nanoscale gold can appear red or purple. At the nanoscale, the motion of the gold's electrons is confined. Because this movement is restricted, gold nanoparticles react differently with light compared to larger-scale gold particles.

estrogen in water affects fish

New research shows that hormones found in birth control pills alter the genes in fish, which can cause changes in their behavior. ... The hormone ethinyl-estradiol (EE2) is an active substance in many birth control pills which affects aquatic organisms when released as waste into the water

how do people breathe in submarines?

Oxygen is supplied either from pressurized tanks, an oxygen generator (which can form oxygen from the electrolysis of water or by some other means) or some sort of "oxygen canister" (You may remember these canisters because of their problems on the MIR space station -- they release oxygen by a very hot chemical reaction). Oxygen is either released continuously by a computerized system that senses the percentage of oxygen in the air, or it is released in batches periodically through the day. Carbon dioxide can be removed from the air chemically using soda lime (sodium hydroxide and calcium hydroxide). The carbon dioxide is trapped in the soda lime by a chemical reaction and removed from the air. Other similar reactions can accomplish the same goal. The moisture can be removed by a dehumidifier or chemically. This prevents it from condensing on the walls and equipment inside the ship.

what is quartz made of

Quartz is an igneous rock that is composed of oxygen and silicon atoms in a continuous makeup of silicon-oxygen tetrahedra (SiO4). Each individual oxygen atom is shared between two tetrahedra atoms, giving quartz the final chemical formula scientifically known as SiO2

Bedrock

Rock that makes up Earth's crust; also the solid rock layer beneath the soil Bedrock essentially refers to the substructure composed of hard rock exposed or buried at the earth's surface; an exposed portion of bedrock is often called an outcrop. Bedrock may have various chemical and mineralogical compositions and can be igneous, metamorphic or sedimentary in origin. The bedrock may be overlain by broken and weathered regolith which includes soil and the subsoil.

how does a rocket engine work?

Rocket engines are fundamentally different. Rocket engines are reaction engines. The basic principle driving a rocket engine is the famous Newtonian principle that "to every action there is an equal and opposite reaction." A rocket engine is throwing mass in one direction and benefiting from the reaction that occurs in the other direction as a result. This concept of "throwing mass and benefiting from the reaction" can be hard to grasp at first, because that does not seem to be what is happening. Rocket engines seem to be about flames and noise and pressure, not "throwing things." Let's look at a few examples to get a better picture of reality: If you have ever shot a shotgun, especially a big 12-gauge shotgun, then you know that it has a lot of "kick." That is, when you shoot the gun it "kicks" your shoulder back with a great deal of force. That kick is a reaction. A shotgun is shooting about an ounce of metal in one direction at about 700 miles per hour, and your shoulder gets hit with the reaction. If you were wearing roller skates or standing on a skateboard when you shot the gun, then the gun would be acting like a rocket engine and you would react by rolling in the opposite direction. If you have ever seen a big fire hose spraying water, you may have noticed that it takes a lot of strength to hold the hose (sometimes you will see two or three firefighters holding the hose). The hose is acting like a rocket engine. The hose is throwing water in one direction, and the firefighters are using their strength and weight to counteract the reaction. If they were to let go of the hose, it would thrash around with tremendous force. If the firefighters were all standing on skateboards, the hose would propel them backward at great speed! When you blow up a balloon and let it go so that it flies all over the room before running out of air, you have created a rocket engine. In this case, what is being thrown is the air molecules inside the balloon. Many people believe that air molecules don't weigh anything, but they do (see the page on helium to get a better picture of the weight of air). When you throw them out the nozzle of a balloon, the rest of the balloon reacts in the opposite direction. Imagine the following situation: You are wearing a spacesuit and you are floating in space beside the space shuttle; you happen to have a baseball in your hand. If you throw the baseball, your body will react by moving in the opposite direction of the ball. The thing that controls the speed at which your body moves away is the weight of the baseball that you throw and the amount of acceleration that you apply to it. Mass multiplied by acceleration is force (f = m * a). Whatever force you apply to the baseball will be equalized by an identical reaction force applied to your body (m * a = m * a). So let's say that the baseball weighs 1 pound, and your body plus the space suit weighs 100 pounds. You throw the baseball away at a speed of 32 feet per second (21 mph). That is to say, you accelerate the 1-pound baseball with your arm so that it obtains a velocity of 21 mph. Your body reacts, but it weighs 100 times more than the baseball. Therefore, it moves away at one-hundredth the velocity of the baseball, or 0.32 feet per second (0.21 mph). If you want to generate more thrust from your baseball, you have two options: increase the mass or increase the acceleration. You can throw a heavier baseball or throw a number of baseballs one after another (increasing the mass), or you can throw the baseball faster (increasing the acceleration on it). But that is all that you can do. A rocket engine is generally throwing mass in the form of a high-pressure gas. The engine throws the mass of gas out in one direction in order to get a reaction in the opposite direction. The mass comes from the weight of the fuel that the rocket engine burns. The burning process accelerates the mass of fuel so that it comes out of the rocket nozzle at high speed. The fact that the fuel turns from a solid or liquid into a gas when it burns does not change its mass. If you burn a pound of rocket fuel, a pound of exhaust comes out the nozzle in the form of a high-temperature, high-velocity gas. The form changes, but the mass does not. The burning process accelerates the mass. The "strength" of a rocket engine is called its thrust. Thrust is measured in "pounds of thrust" in the U.S. and in Newtons under the metric system (4.45 Newtons of thrust equals 1 pound of thrust). A pound of thrust is the amount of thrust it would take to keep a 1-pound object stationary against the force of gravity on Earth. So on Earth, the acceleration of gravity is 32 feet per second per second (21 mph per second). If you were floating in space with a bag of baseballs and you threw one baseball per second away from you at 21 mph, your baseballs would be generating the equivalent of 1 pound of thrust. If you were to throw the baseballs instead at 42 mph, then you would be generating 2 pounds of thrust. If you throw them at 2,100 mph (perhaps by shooting them out of some sort of baseball gun), then you are generating 100 pounds of thrust, and so on. One of the funny problems rockets have is that the objects that the engine wants to throw actually weigh something, and the rocket has to carry that weight around. So let's say that you want to generate 100 pounds of thrust for an hour by throwing one baseball every second at a speed of 2,100 mph. That means that you have to start with 3,600 1-pound baseballs (there are 3,600 seconds in an hour), or 3,600 pounds of baseballs. Since you only weigh 100 pounds in your spacesuit, you can see that the weight of your "fuel" dwarfs the weight of the payload (you). In fact, the fuel weights 36 times more than the payload. And that is very common. That is why you have to have a huge rocket to get a tiny person into space right now -- you have to carry a lot of fuel. The Orbiter weighs 165,000 pounds empty. The external tank weighs 78,100 pounds empty. The two solid rocket boosters weigh 185,000 pounds empty each. But then you have to load in the fuel. Each SRB holds 1.1 million pounds of fuel. The external tank holds 143,000 gallons of liquid oxygen (1,359,000 pounds) and 383,000 gallons of liquid hydrogen (226,000 pounds). The whole vehicle -- shuttle, external tank, solid rocket booster casings and all the fuel -- has a total weight of 4.4 million pounds at launch. 4.4 million pounds to get 165,000 pounds in orbit is a pretty big difference! To be fair, the orbiter can also carry a 65,000-pound payload (up to 15 x 60 feet in size), but it is still a big difference. The fuel weighs almost 20 times more than the Orbiter [source: The Space Shuttle Operator's Manual]. All of that fuel is being thrown out the back of the Space Shuttle at a speed of perhaps 6,000 mph (typical rocket exhaust velocities for chemical rockets range between 5,000 and 10,000 mph). The SRBs burn for about two minutes and generate about 3.3 million pounds of thrust each at launch (2.65 million pounds average over the burn). The three main engines (which use the fuel in the external tank) burn for about eight minutes, generating 375,000 pounds of thrust each during the burn. The idea behind a simple solid-fuel rocket is straightforward. What you want to do is create something that burns very quickly but does not explode. As you are probably aware, gunpowder explodes. Gunpowder is made up 75% nitrate, 15% carbon and 10% sulfur. In a rocket engine, you don't want an explosion -- you would like the power released more evenly over a period of time. Therefore you might change the mix to 72% nitrate, 24% carbon and 4% sulfur. In this case, instead of gunpowder, you get a simple rocket fuel. This sort of mix will burn very rapidly, but it does not explode if loaded properly. Here's a typical cross section: On the left you see the rocket before ignition. The solid fuel is shown in green. It is cylindrical, with a tube drilled down the middle. When you light the fuel, it burns along the wall of the tube. As it burns, it burns outward toward the casing until all the fuel has burned. In a small model rocket engine or in a tiny bottle rocket the burn might last a second or less. In a Space Shuttle SRB containing over a million pounds of fuel, the burn lasts about two minutes. The propellant mixture in each SRB motor consists of an ammonium perchlorate (oxidizer, 69.6 percent by weight), aluminum (fuel, 16 percent), iron oxide (a catalyst, 0.4 percent), a polymer (a binder that holds the mixture together, 12.04 percent), and an epoxy curing agent (1.96 percent). The propellant is an 11-point star-shaped perforation in the forward motor segment and a double- truncated- cone perforation in each of the aft segments and aft closure. This configuration provides high thrust at ignition and then reduces the thrust by approximately a third 50 seconds after lift-off to prevent overstressing the vehicle during maximum dynamic pressure. [source: NASA] All kinds of fuel combinations get used in liquid propellant rocket engines. For example: Liquid hydrogen and liquid oxygen - used in the Space Shuttle main engines Gasoline and liquid oxygen - used in Goddard's early rockets Kerosene and liquid oxygen - used on the first stage of the large Saturn V boosters in the Apollo program Alcohol and liquid oxygen - used in the German V2 rockets Nitrogen tetroxide/monomethyl hydrazine - used in the Cassini engines We are accustomed to seeing chemical rocket engines that burn their fuel to generate thrust. There are many other ways to generate thrust however. Any system that throws mass would do. If you could figure out a way to accelerate baseballs to extremely high speeds, you would have a viable rocket engine. The only problem with such an approach would be the baseball "exhaust" (high-speed baseballs at that) left streaming through space. This small problem causes rocket engine designers to favor gases for the exhaust product. Many rocket engines are very small. For example, attitude thrusters on satellites don't need to produce much thrust. One common engine design found on satellites uses no "fuel" at all -- pressurized nitrogen thrusters simply blow nitrogen gas from a tank through a nozzle. Thrusters like these kept Skylab in orbit, and are also used on the shuttle's manned maneuvering system. New engine designs are trying to find ways to accelerate ions or atomic particles to extremely high speeds to create thrust more efficiently. NASA's Deep Space-1 spacecraft was the first to use ion engines for propulsion [source: SPACE.com]. See this page for additional discussion of plasma and ion engines.

Salyut: the First Space Station

Russia (then known as the Soviet Union) was the first to place a space station. The Salyut 1 station, which went into orbit in 1971, was actually a combination of the Almaz and Soyuz spacecraft systems. The Almaz system was originally designed for space military purposes, but repurposed for the civilian Salyut space station. The Soyuz spacecraft ferried cosmonauts from Earth to the space station and back. Salyut 1 was about 45 feet (15 meters) long and held three main compartments that housed dining and recreation areas, food and water storage, a toilet, control stations, exercise equipment and scientific equipment. Initially, the Soyuz 10 crew was supposed to live aboard Salyut 1, but their mission was plagued with docking problems that prevented them from entering the space station. The Soyuz 11 crew was the first crew to successfully live on Salyut 1, which they did for 24 days. However, the crew of Soyuz 11 tragically died upon returning to Earth when the Soyuz 11 capsule depressurized during reentry. Further missions to Salyut 1 were canceled, and the Soyuz spacecraft was redesigned. After Soyuz 11, the Soviets launched another space station, Salyut 2, but it failed to reach orbit. The Soviets followed with Salyuts 3-5. These flights tested the new Soyuz spacecraft and crews manned these stations for increasingly longer missions. One drawback with these space stations was that they had only one docking port for the Soyuz spacecraft and could not be re-supplied from Earth by other ships. On Sept. 29, 1977, the Soviets launched Salyut 6. This station had a second docking port where the station could be resupplied by an unmanned docking supply ship called Progress. Salyut 6 operated between 1977 and 1982. In 1982, Salyut 7, the last of the Salyut program was launched. It hosted 11 crews and was inhabited for 800 days. The Salyut program eventually led to the development of Russia's Mir space station, which we will talk about a little later. But first, let's look at America's first space station: Skylab. The United States placed its first, and only, space station, called Skylab 1, in orbit in 1973. During the launch, the station was damaged. A critical meteoroid shield and one of the station's two main solar panels were ripped off and the other solar panel was not fully stretched out. That meant that Skylab had little electrical power and the internal temperature rose to 126 degrees Fahrenheit (52 degrees Celsius). The first crew, Skylab2, was launched 10 days later to fix the ailing station. The crew consisted of Commander Charles "Pete" Conrad, Paul Weitz and Joseph Kerwin. The Skylab 2 astronauts stretched out the remaining solar panel and set up an umbrella-like sunshade to cool the station. With the station repaired, the astronauts spent 28 days in space conducting scientific and biomedical research. In 1986, the Russians launched the Mir space station, which was intended to be a permanent home in space. The first crew, cosmonauts Leonid Kizim and Vladymir Solovyov, shuttled between the retiring Salyut 7 and Mir. They spent 75 days aboard Mir. Mir was continually manned and constructed over the next 10 years and contained the following parts: The Russian space agency could no longer afford to maintain Mir, so NASA and the Russian space agency had planned to junk the station in order to concentrate on the ISS. A private movement (Keep Mir Alive!) and a company (MirCorp) publicly campaigned to repair and privatize the aging space station. However, the Russian Space Agency decided on November 16, 2000, to bring Mir down to Earth. In February 2001, Mir's rocket engines were fired to slow it down. Mir re-entered the Earth's atmosphere on March 23, 2001, burned and broke up. Debris crashed in the South Pacific Ocean about 1,000 miles (1,667 km) east of Australia. This marked the end of the first permanent space station. In 1984, President Ronald Reagan proposed that the United States, in cooperation with other countries, build a permanently inhabited space station. Reagan envisioned a station that would have government and industry support. To help with the enormous costs of the station, the U.S. forged a cooperative effort with 14 other countries (Canada, Japan, Brazil, and the European Space Agency, which is comprised of: United Kingdom, France, Germany, Belgium, Italy, the Netherlands, Denmark, Norway, Spain, Switzerland and Sweden). During the planning of the ISS and after the fall of the Soviet Union, the United States invited Russia to cooperate in the ISS in 1993; this brought the number of participating countries to 16. NASA took the lead in coordinating the ISS's construction. The assembly of the ISS in orbit began in 1998. On October 31, 2000, the first crew of the ISS was launched from Russia. The three-member crew spent almost five months aboard the ISS, activating systems and conducting experiments. The ISS has been manned ever since and is scheduled to be finished in 2011. Also set for 2011 is the launch of an orbiting laboratory by China called Tiangong-1. In October, 2003, China became the third nation ever to launch manned spacecraft. Since then, China has been developing a full-fledged space program including a space station. The Tiangong-1 will be capable of docking multiple Shenzhou spacecraft and will serve as the first module of a proposed Chinese space station planned to be completed by 2020. The space station may have both civilian and military purposes. Speaking of the future, let's take a look at what could be in the stars, so to speak, for space stations. We are just beginning the development of space stations. The ISS will be a vast improvement over Salyut, Skylab and Mir; but we are still a long way from the realization of large space stations or colonies as envisioned by science fiction writers. None of our space stations thus far have had any gravity. One reason for this is that we want a place without gravity so that we can study its effects. Another is that we lack the technology to practically rotate a large structure, like a space station, to produce artificial gravity. In the future, artificial gravity will be a requirement for space colonies with large populations.

current transistor size

Silicon's atomic size is about 0.2 nanometers. Today's transistors are about 70 silicon atoms wide, so the possibility of making them even smaller is itself shrinking

harnessing biogas in sewage

Since sewage treatment plants can use biogas generated from their own sludge to power their operations, it allows them to be energy self-sufficient. ... Sludge-to-energy systems harness this methane for energy instead of letting it escape into the atmosphere, where it would fuel climate change.

Slime Mold Grows Network Just Like Tokyo Rail System

Talented and dedicated engineers spent countless hours designing Japan's rail system to be one of the world's most efficient. Could have just asked a slime mold. When presented with oat flakes arranged in the pattern of Japanese cities around Tokyo, brainless, single-celled slime molds construct networks of nutrient-channeling tubes that are strikingly similar to the layout of the Japanese rail system, researchers from Japan and England report Jan. 22 in Science. A new model based on the simple rules of the slime mold's behavior may lead to the design of more efficient, adaptable networks, the team contends. Initially, the slime mold dispersed evenly around the oat flakes, exploring its new territory. But within hours, the slime mold began to refine its pattern, strengthening the tunnels between oat flakes while the other links gradually disappeared. After about a day, the slime mold had constructed a network of interconnected nutrient-ferrying tubes. Its design looked almost identical to that of the rail system surrounding Tokyo, with a larger number of strong, resilient tunnels connecting centrally located oats. "There is a remarkable degree of overlap between the two systems," Fricker says. The behavior of the plasmodium "is really difficult to capture by words," comments biochemist Wolfgang Marwan of Otto von Guericke University in Magdeburg, Germany. "You see they optimize themselves somehow, but how do you describe that?" The new research "provides a simple mathematical model for a complex biological phenomenon," Marwan wrote in an article in the same issue of Science.

Targeted drug delivery

Targeted drug delivery systems have been developed to optimize regenerative techniques. The system is based on a method that delivers a certain amount of a therapeutic agent for a prolonged period of time to a targeted diseased area within the body. e.g. insulin or birth control patches

Bearing capacity

The ability of a soil to support load. In geotechnical engineering, bearing capacity is the capacity of soil to support the loads applied to the ground. The bearing capacity of soil is the maximum average contact pressure between the foundation and the soil which should not produce shear failure in the soil.

gimp

The noun gimp is sometimes used to describe a limp or another physical disability, although it's an outdated and offensive word to use. disability of walking due to crippling of the legs or feet walk impeded by some physical limitation or injury

sterilization

The process that completely destroys all microbial life, including spores.

Fast and slow solar wind

The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between 0.5 and 10 keV. The composition of the solar wind plasma also includes a mixture of materials found in the solar plasma: trace amounts of heavy ions and atomic nuclei C, N, O, Ne, Mg, Si, S, and Fe. There are also rarer traces of some other nuclei and isotopes such as P, Ti, Cr ,Ni, Fe 54 and 56, and Ni 58,60,62.[2] Embedded within the solar-wind plasma is the interplanetary magnetic field.[3] The solar wind varies in density, temperature and speed over time and over solar latitude and longitude. Its particles can escape the Sun's gravity because of their high energy resulting from the high temperature of the corona, which in turn is a result of the coronal magnetic field. The solar wind is observed to exist in two fundamental states, termed the slow solar wind and the fast solar wind, though their differences extend well beyond their speeds. In near-Earth space, the slow solar wind is observed to have a velocity of 300-500 km/s, a temperature of ~105 K and a composition that is a close match to the corona. By contrast, the fast solar wind has a typical velocity of 750 km/s, a temperature of 8×105 K and it nearly matches the composition of the Sun's photosphere.[33] The slow solar wind is twice as dense and more variable in nature than the fast solar wind. The slow solar wind appears to originate from a region around the Sun's equatorial belt that is known as the "streamer belt", where coronal streamers are produced by magnetic flux open to the heliosphere draping over closed magnetic loops. The exact coronal structures involved in slow solar wind formation and the method by which the material is released is still under debate. Observations of the Sun between 1996 and 2001 showed that emission of the slow solar wind occurred at latitudes up to 30-35° during the solar minimum (the period of lowest solar activity), then expanded toward the poles as the solar cycle approached maximum. At solar maximum, the poles were also emitting a slow solar wind. The fast solar wind originates from coronal holes,[38] which are funnel-like regions of open field lines in the Sun's magnetic field.[39] Such open lines are particularly prevalent around the Sun's magnetic poles. The plasma source is small magnetic fields created by convection cells in the solar atmosphere. These fields confine the plasma and transport it into the narrow necks of the coronal funnels, which are located only 20,000 kilometers above the photosphere. The plasma is released into the funnel when these magnetic field lines reconnect.

Space suit design

The space suit provides air pressure to keep the fluids in your body in a liquid state -- in other words, to prevent your bodily fluids from boiling. Space suits cannot use normal air -- 78 percent nitrogen, 21 percent oxygen and 1 percent other gases -- because the low pressure would cause dangerously low oxygen concentrations in the lungs and blood, much like climbing Mt. Everest does. So, most space suits provide a pure oxygen atmosphere for breathing. Space suits get the oxygen either from a spacecraft via an umbilical cord or from a backpack life support system that the astronaut wears. Both the shuttle and the International Space Station have normal air mixtures that mimic our atmosphere. Therefore, to go into a pure oxygen space suit, a spacewalking astronaut must "pre-breathe" pure oxygen for some period of time before suiting up. This pre-breathing of pure oxygen eliminates the nitrogen from the astronaut's blood and tissues, thereby minimizing the risk of the bends. The astronaut breathes out carbon dioxide. In the confined space of the suit, carbon dioxide concentrations would build up to deadly levels. Therefore, excess carbon dioxide must be removed from the space suit's atmosphere. Space suits use lithium hydroxide canisters to remove carbon dioxide. These canisters are located either in the space suit's life support backpack or in the spacecraft, in which case they are accessed through an umbilical cord. To protect the astronauts from collisions with micrometeoroids, space suits have multiple layers of durable fabrics such as Dacron or Kevlar. These layers also prevent the suit from tearing on exposed surfaces of the spacecraft or a planet or moon. Space suits offer only limited protection from radiation. Some protection is offered by the reflective coatings of Mylar that are built into the suits, but a space suit would not offer much protection from a solar flare. So, spacewalks are planned during periods of low solar activity. Space suits have helmets that are made of clear plastic or durable polycarbonate. Most helmets have coverings to reflect sunlight, and tinted visors to reduce glare, much like sunglasses. Also, prior to a spacewalk, the inside faceplates of the helmet are sprayed with an anti-fog compound. Finally, modern space suit helmet coverings have mounted lights so that the astronauts can see into the shadows. Moving within an inflated space suit is tough. Imagine trying to move your fingers in a rubber glove blown up with air; it doesn't give very much. To help this problem, space suits are equipped with special joints or tapers in the fabric to help the astronauts bend their hands, arms, legs, knees and ankles. Space suits are equipped with radio transmitters/receivers so that spacewalking astronauts can talk with ground controllers and/or other astronauts. The astronauts wear headsets with microphones and earphones. The transmitters/receivers are located in the chestpacks/backpacks worn by the astronauts. In weightlessness, it is difficult to move around. If you push on something, you fly off in the opposite direction (Newton's third law of motion -- for every action there is an equal and opposite reaction). Gemini spacewalking astronauts reported great problems with just maintaining their positions; when they tried to turn a wrench, they spun in the opposite direction. Therefore, spacecraft are equipped with footholds and hand restraints to help astronauts work in microgravity. In addition, before the mission, astronauts practice spacewalking in big water tanks on Earth. The buoyancy of an inflated space suit in water simulates microgravity. NASA has also developed some gas-powered rocket maneuvering devices to allow astronauts to move freely in space without being tethered to the spacecraft. One such device, which was called the Manned Maneuvering Unit (MMU), was basically a gas-thruster powered chair with a joystick control. NASA has also developed a nitrogen-gas propelled unit that fits on the backpack, called the Simplified Aid for Extravehicular Activity Rescue (SAFER). The SAFER can help an astronaut return to the shuttle or station in the event that he/she gets separated from the spacecraft. The SAFER holds 3.1 lb (1.4 kg) of nitrogen propellant and can change an astronaut's velocity by a maximum of about 9 feet/second (3 meters/second). When jet aircraft were developed, pilots needed pressurized flight suits to cope with the low atmospheric pressure and lack of oxygen at high altitudes. Most of these suits were designed to be used only when the pressurized cabin failed. The suits consisted of neoprene rubber-coated fabric that could inflate like a balloon, and a more rigid fabric over the neoprene to restrain the suit and direct the pressure inward on the pilot. Hoses were attached from the plane to the suit to provide oxygen. When NASA's Mercury program started, the space suits kept the designs of the early pressurized flight suits, but added layers of aluminized Mylar over the neoprene rubber. The Apollo suit consisted of the following: - A water-cooled nylon undergarment - A multi-layered pressure suit: inside layer - lightweight nylon with fabric vents; middle layer - neoprene-coated nylon to hold pressure; outer layer - nylon to restrain the pressurized layers beneath - Five layers of aluminized Mylar interwoven with four layers of Dacron for heat protection - Two layers of Kapton for additional heat protection - A layer of Teflon-coated cloth (nonflammable) for protection from scrapes - A layer of white Teflon cloth (nonflammable) - The suit had boots, gloves, a communications cap and a clear plastic helmet. During liftoff, the suit's oxygen and cooling water were supplied by the ship. For walking on the moon, the space suit was supplemented with a pair of protective overboots, gloves with rubber fingertips, a set of filters/visors worn over the helmet for protection from sunlight, and a portable life support backpack that contained oxygen, carbon-dioxide removal equipment and cooling water. The space suit and backpack weighed 180 lb on Earth, but only 30 lb on the moon. While early space suits were made entirely of soft fabrics, today's Extravehicular Mobility Unit (EMU) has a combination of soft and hard components to provide support, mobility and comfort. The suit itself has 13 layers of material, including an inner cooling garment (two layers), pressure garment (two layers), thermal micrometeoroid garment (eight layers) and outer cover (one layer). The materials used include: - Nylon tricot - Spandex - Urethane-coated Nylon - Dacron - Neoprene-coated Nylon - Mylar - Gortex - Kevlar (material in bullet-proof vests) - Nomex All of the layers are sewn and cemented together to form the suit. In contrast to early space suits, which were individually tailored for each astronaut, the EMU has component pieces of varying sizes that can be put together to fit any given astronaut. The EMU consists of the following parts: - Maximum Absorption Garment (MAG) - collects urine produced by the astronaut - Liquid Cooling and Ventilation Garment (LCVG) - removes excess body heat produced by the astronaut during spacewalks - EMU Electrical Harness (EEH) - provides connections for communications and bio-instruments - Communications Carrier Assembly (CCA) - contains microphones and earphones for communications - Lower Torso Assembly (LTA) - lower half of the EMU including pants, knee and ankle joints, boots and lower waist - Hard Upper Torso (HUT) - hard fiberglass shell that supports several structures including the arms, torso, helmet, life-support backpack and control module - Arms - Gloves - outer and inner gloves - Helmet - Extravehicular Visor Assembly (EVA) - protects the astronaut from bright sunlight - In-suit Drink Bag (IDB) - provides drinking water for the astronaut during the spacewalk - Primary Life Support Subsystem (PLSS) - provides oxygen, power, carbon dioxide removal, cooling water, radio equipment and warning system - Secondary Oxygen Pack (SOP) - provides emergency oxygen supply - Display and Control Module (DCM) - displays and controls to run the PLSS

how much energy is lost in power transmission?

The transmission over long distances creates power losses. The major part of the energy losses comes from Joule effect in transformers and power lines. The energy is lost as heat in the conductors. The overall losses between the power plant and consumers is then in the range between 8 and 15% Joule effect: the heating that occurs when an electric current flows through a resistance.

ultrasound test how it works

The ultrasound machine transmits high-frequency (1 to 5 megahertz) sound pulses into your body using a probe. The sound waves travel into your body and hit a boundary between tissues (e.g. between fluid and soft tissue, soft tissue and bone). ... The reflected waves are picked up by the probe and relayed to the machine. I don't know how completely you'll get this but I'll make it as easy to understand as I can. High-frequency sound waves are emitted into the body using the transducer. You can call that a "probe". The sound waves hit obstacles — soft tissue like fat and muscle, hard tissue like bone, fluid and air. Foreign objects in the body also reflect sound waves according to their composition. Solids reflect sound waves strongly. Sound bounces off solids well. Fluids a bit less strongly and and air reflects sound waves even less strongly. Makes sense, right? Organs and structures closer to the source of the sound waves bounce back signals more quickly than structures and organs farther away. Makes sense again, right? The strength and speed of the reflected sounds waves create a 3-dimensional visual image.

process control

To monitor and control a process so that the quality of the output/product improves. monitor/inspect efficiency

how to calculate torque?

Torque = Distance x Force

Optogenetics

Transgenic technique that combines genetics and light to control targeted cells in living tissue Optogenetics (from Greek optikós, meaning 'seen, visible') most commonly refers to a biological technique that involves the use of light to control cells in living tissue, typically neurons, that have been genetically modified to express light-sensitive ion channels. As such, optogenetics is a neuromodulation method that uses a combination of techniques from optics and genetics to control the activities of individual neurons in living tissue—even within freely-moving animals. In some usages, optogenetics also refers to optical monitoring of neuronal activity and control of biochemical pathways in non-neuronal cells, although these research activities preceded the use of light-sensitive ion channels in neurons. As optogenetics is used by some authors to refer to only optical control of the activity of genetically defined neurons and not these additional research approaches, the term optogenetics is an example of polysemy. Neuronal control is achieved using optogenetic actuators like channelrhodopsin, halorhodopsin, and archaerhodopsin, while optical recording of neuronal activities can be made with the help of optogenetic sensors for calcium (GCaMPs), vesicular release (synapto-pHluorin), neurotransmitters (GluSnFRs), or membrane voltage (Quasars, ASAPs). Control (or recording) of activity is restricted to genetically defined neurons and performed in a spatiotemporal-specific manner by light. In 2010, optogenetics was chosen as the "Method of the Year" across all fields of science and engineering by the interdisciplinary research journal Nature Methods.[9] At the same time, optogenetics was highlighted in the article on "Breakthroughs of the Decade" in the academic research journal Science.

electrostatic filters

Uses static electricity to capture particulates as small as 10 microns Used in residential and small commercial buildings Particles are attracted to charges opposite of their own

vector (physics)

Vector, in physics, a quantity that has both magnitude and direction. It is typically represented by an arrow whose direction is the same as that of the quantity and whose length is proportional to the quantity's magnitude.

are bacteria or viruses larger?

Viruses are very small infectious agents that can only replicate inside other living cells. ... Bacteria are slightly larger than viruses and are made up of a single cell. They are very simple organisms, and most can replicate outside other cells.

quartering wind

Winds hitting the corner of a structure

Mylar

a form of polyester resin used to make heat-resistant plastic films and sheets. BoPET (biaxially-oriented polyethylene terephthalate) is a polyester film made from stretched polyethylene terephthalate (PET) and is used for its high tensile strength, chemical and dimensional stability, transparency, reflectivity, gas and aroma barrier properties, and electrical insulation. Five layers of metallized boPET film in NASA's spacesuits make them radiation resistant and help regulate temperature.

Finite Element Analysis (FEA)

a mathematical method used to determine mechanical characteristics, such as stresses of structures under load The calculation and simulation of unknown factors in products using CAD systems. For example, simulating the stresses within a welded car part. The finite element method is the most largely used method for solving problems of engineering and mathematical models. Typical problem areas of interest include the traditional fields of structural analysis, heat transfer, fluid flow, mass transport, and electromagnetic potential.

Feedforward control

a mechanism for monitoring performance inputs rather than outputs to prevent or minimize performance deficiencies before they occur control that allows managers to anticipate problems before they arise Feedforward is the concept of learning from the future concerning the desired behavior which the subject is encouraged to adopt.

riff

a short, catchy, and repeated melodic phrase. A riff is a short section of music, especially in jazz. When you're first learning to play the saxophone, you may just play the same riff over and over.

Frame of reference

a system of objects that are not moving with respect to one another The sum of a person's knowledge, experience, goals, values, and attitudes. No two people can have exactly the same frame of reference. a set of criteria or stated values in relation to which measurements or judgments can be made.

Bacteriophage

a virus that parasitizes a bacterium by infecting it and reproducing inside it.

erratum

an error in writing a mistake in printed matter resulting from mechanical failures of some kind

Central nervous system

brain and spinal cord The central nervous system (CNS) is the part of the nervous system consisting of the brain and spinal cord. The CNS is so named because it integrates the received information and coordinates and influences the activity of all parts of the bodies of bilaterally symmetric animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish—and it contains the majority of the nervous system.

capsaicin

chemical that stimulates receptors that respond to painful heat Capsaicin (8-methyl-N-vanillyl-6-nonenamide) is an active component of chili peppers, which are plants belonging to the genus Capsicum. It is an irritant for mammals, including humans, and produces a sensation of burning in any tissue with which it comes into contact. Capsaicin topical is used for temporary relief of muscle or joint pain caused by strains, sprains, arthritis, bruising, or backaches. Capsaicin topical is also used to treat nerve pain (neuralgia) in people who have had herpes zoster, or "shingles.

Nanocrystal

colorless crystals that reflect different amounts of light A nanocrystal is a material particle having at least one dimension smaller than 100 nanometres, based on quantum dots (a nanoparticle) and composed of atoms in either a single- or poly-crystalline arrangement. The size of nanocrystals distinguishes them from larger crystals. Nanocrystals made with zeolite are used to filter crude oil into diesel fuel at an ExxonMobil oil refinery in Louisiana at a cost less than conventional methods.[10]

hypertrophic cardiomyopathy

heart muscle becomes enlarged and blocks blood flow Hypertrophic cardiomyopathy (HCM) is a disease in which the heart muscle (myocardium) becomes abnormally thick (hypertrophied). The thickened heart muscle can make it harder for the heart to pump blood

fail-safe

in software, a program that stops operating to avoid harm causing a piece of machinery or other mechanism to revert to a safe condition in the event of a breakdown or malfunction. a system or plan that comes into operation in the event of something going wrong or that is there to prevent such an occurrence.

reverse pharmacology

isolate a compound and see on which target from a catalog of existing targets it will have activity In the field of drug discovery, reverse pharmacology also known as target-based drug discovery (TDD), a hypothesis is first made that modulation of the activity of a specific protein target will have beneficial therapeutic effects. Screening of chemical libraries of small molecules is then used to identify compounds that bind with high affinity to the target. The hits from these screens are then used as starting points for drug discovery. This method became popular after the sequencing of the human genome which allowed rapid cloning and synthesis of large quantities of purified proteins. This method is the most widely used in drug discovery today. Differently than the classical (forward) pharmacology, with the reverse pharmacology approach in vivo efficacy of identified active (lead) compounds is usually performed in the final drug discovery stages. Identify a protein and then figure out how it relates to the condition you want to treat.

nerve net

loosely organized network of nerve cells that together allow cnidarians to detect stimuli (in invertebrates such as coelenterates and flatworms) a diffuse network of neurons which conducts impulses in all directions from a point of stimulus. A nerve net consists of interconnected neurons lacking a brain or any form of cephalization. While organisms with bilateral body symmetry are normally associated with a central nervous system, organisms with radial symmetry are associated with nerve nets. jellyfish have this

sanitation

maintaining a clean condition in order to promote hygiene and prevent disease different from sanitation which completely destroys all microbial life, including spores.

transitional flow

mixture of laminar and turbulent flow usually turbulent in the middle and laminer near the edges. kinda like a river

kleptomaniac

person who has a compulsive desire to steal pathological thief

emulsification

physical process of breaking up large fat globules into smaller globules, thereby increasing the surface area that enzymes can use to digest the fat An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable). Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion should be used when both phases, dispersed and continuous, are liquids. In an emulsion, one liquid (the dispersed phase) is dispersed in the other (the continuous phase). Examples of emulsions include vinaigrettes, homogenized milk, and some cutting fluids for metal working.

Biomass energy

renewable energy derived from burning organic materials such as wood and alcohol (ethanol) Biomass energy is energy generated or produced by living or once-living organisms. The most common biomass materials used for energy are plants, such as corn and soy, above. The energy from these organisms can be burned to create heat or converted into electricity. We use four types of biomass today—wood and agricultural products,solid waste, landfill gas and biogas, and alcohol fuels (like Ethanol or Biodiesel). Most biomass used today is home grown energy. Wood—logs, chips, bark, and sawdust—accounts for about 44 percent of biomass energy.

vacuum gripper

robot mechanism that allows it to pick up objects via a vacuum

bit

stands for binary digit

error

the difference between the experimental value and the accepted value the difference between the setpoint and the current value e.g. set at 70F and its 60F the error is -10.

Joule effect

the heating that occurs when an electric current flows through a resistance. Joule heating, also known as Ohmic heating and resistive heating, is the process by which the passage of an electric current through a conductor produces heat. resistance

water table

the level below which the ground is saturated with water.

automatism

the performance of actions without conscious thought or intention. any reaction that occurs automatically without conscious thought or reflection (especially the undirected behavior seen in psychomotor epilepsy) something you so do often it just becomes subconsciously engrained

impermanence

the property of not existing for indefinitely long durations

germinate

to begin to grow, come into being; sprout Germination is the process by which an organism grows from a seed or similar structure. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm

concentric tube heat exchanger

tube in tube heat exchanger. counterflow used in heat pumps / geothermal

Geotechnical engineering

uses the principles of mechanics to analyze and predict the behavior of earth materials Geotechnics is the application of scientific methods and engineering principles to the acquisition, interpretation, and use of knowledge of materials of the Earth's crust and earth materials for the solution of engineering problems and the design of engineering works.

Laparoscopy

visual examination of the abdominal cavity using an endoscope is an operation performed in the abdomen or pelvis using small incisions with the aid of a camera. The laparoscope aids diagnosis or therapeutic interventions with a few small cuts in the abdomen.

Supersolid

A supersolid is a spatially ordered material with superfluid properties. Superfluidity is a special quantum state of matter in which a substance flows with zero viscosity. A supersolid is a spatially ordered material with superfluid properties. In the case of helium-4, it has been conjectured since the 1960s that it might be possible to create a supersolid. Starting from 2017, a definitive proof for the existence of this state was provided by several experiments using atomic Bose-Einstein condensates. The general conditions required for supersolidity to emerge in a certain substance are a topic of ongoing research. A supersolid is a special quantum state of matter where particles form a rigid, spatially ordered structure, but also flow with zero viscosity. This is in contradiction to the intuition that flow, and in particular superfluid flow with zero viscosity, is a property exclusive to the fluid state, e.g. superconducting electron and neutron fluids, gases with Bose-Einstein condensates, or unconventional liquids such as helium-4 or helium-3 at sufficiently low temperature. For more than 50 years it was thus unclear whether the supersolid state can exist.

zeer pot

A zeer pot is an evaporative cooler used in rural Africa and the Middle East to keep vegetables fresh. They consist of two terra cotta pots, one nested inside the other, with the gap between them filled with wet sand. The sand serves as a thermal mass that helps keep the pot cold once it has cooled down, and acts as a wick to spread the moisture up the walls of the pot. When placed in a shaded, breezy location, the evaporation of water off the outer surface chills the pot. If you have a good breeze, or a fan powered by a solar panel blowing the pot, the pot can get quite cold. Imagine that chill you get when you step out of a pool when the wind is blowing. Now imagine that wet wind chill going on all day. That's what the pot feels with a constant breeze.

elastomers

highly accurate elastic impression materials that have qualities similar to rubber; they are used extensively in indirect restorative techniques, such as crown and bridge procedures long chain polymers a natural or synthetic polymer having elastic properties, e.g. rubber. An elastomer is a polymer with viscoelasticity and has very weak intermolecular forces, generally low Young's modulus and high failure strain compared with other materials.

Plasticizer

liquid added to acrylic resin to soften it and make it more pliable Plasticizers or dispersants are additives that decrease the plasticity or decrease the viscosity of a material. These are the substances which are added in order to alter their physical properties. These are either liquids with low volatility or solids. Plasticisers (US: plasticizers) are colourless and odourless liquids used primarily to soften plastic. Over 85% of all plasticisers consumed in Europe are employed in durable flexible PVC applications, largely for the construction, automotive and wire & cable sectors. added to pliable PVC

shear stress

stress that occurs when forces act in parallel but opposite directions, pushing parts of a solid in opposite directions Shear stress, force tending to cause deformation of a material by slippage along a plane or planes parallel to the imposed stress. The resultant shear is of great importance in nature, being intimately related to the downslope movement of earth materials and to earthquakes.

fugacity

the activity of a gas Fugacity is the quality of impermanence. With plants, fugacity refers to the parts that drop off. In chemistry, it's the tendency of a gas to expand till it dissipates. Fugacity can also refer to things that don't last, like youth. In chemical thermodynamics, the fugacity of a real gas is an effective partial pressure which replaces the mechanical partial pressure in an accurate computation of the chemical equilibrium constant. It is equal to the pressure of an ideal gas which has the same temperature and molar Gibbs free energy as the real gas.

brownian motion

the chaotic movement of colloidal particles, caused by collision with particles of the solvent in which they are dispersed Brownian motion or pedesis is the random motion of particles suspended in a fluid resulting from their collision with the fast-moving molecules in the fluid. This pattern of motion typically alternates random fluctuations in a particle's position inside a fluid sub-domain with a relocation to another sub-domain the erratic random movement of microscopic particles in a fluid, as a result of continuous bombardment from molecules of the surrounding medium.

threshing

the separation of grain or seeds from the husks and straw separate grain from (a plant), typically with a flail or by the action of a revolving mechanism.

mass flux

time rate of mass flow per unit area In physics and engineering, mass flux is the rate of mass flow per unit area, perfectly overlapping with the momentum density, the momentum per unit volume. The common symbols are j, J, q, Q, φ, or Φ, sometimes with subscript m to indicate mass is the flowing quantity. Its SI units are kg s⁻¹ m⁻².

piezometer

used to measure hydraulic head an instrument for measuring the pressure of a liquid or gas, or something related to pressure (such as the compressibility of liquid). Piezometers are often placed in boreholes to monitor the pressure or depth of groundwater. A piezometer is either a device used to measure liquid pressure in a system by measuring the height to which a column of the liquid rises against gravity, or a device which measures the pressure of groundwater at a specific point

absorption column

Absorption columns are intended to provide a high interfacial contact area to the gas stream and liquid stream so that the mass transfer of a particular component from the gas to the liquid (solvent) can be enhanced. So the ultimate aim is that a component of gas is to be dissolved in liquid solvent. It requires a distribution of that component between the gas phase and the liquid phase. Why low temperatures? According to the Henry's law, the solubility of a gas or volatile substance in a liquid solvent generally decreases with increase in temperature (after passing through a minima). As the aim is to disssolve more substance into the liquid, the desirable condition is the condition at which the solubility of gas is high. so the temperature should be low. Rault's law says the vapor pressure of a solvent is also temperature dependent. Higher the temperature, more will be the vapor pressure. This means more molecules will leave the liquid phase and the liquid will go the vapor phase. At high temperatures , this will cause the loss of solvent which is very valuable and costly and as this loss is undesirable, the temperature should be low. Why high Pressure? According to Henry's law, higher the partial pressure, more will be the amount of gas dissolved in liquid. Also this means higher is the solubility. The partial pressure is directly propotional to the total pressure (Dalton's law). This means higher is the total pressure, more is the partial pressure. This means high Total Pressure ensures high dissolution of gas and increased mass transfer rates. High total pressure prevents the solvent to evaporate. so it also reduces the solvent losses. So, both high pressure and low temperature are for the same 2 reasons. to increase the amount of component dissolved in liquid to prevent the volatilization of the solvent.

what are powerline conductors made of?

Aluminium conductor steel-reinforced cable (ACSR) is a type of high-capacity, high-strength stranded conductor typically used in overhead power lines. The outer strands are high-purity aluminium, chosen for its good conductivity, low weight and low cost. Aluminum around steel, since aluminum is too weak and copper is too expensive.

Extensometer

An instrument to measure change in length of a tensile specimen, thus allowing calculation of strain.

mosfet vs bjt

BJT is a Bipolar Junction Transistor, while MOSFET is a Metal Oxide Semiconductor Field-Effect Transistor. 2. A BJT has an emitter, collector and base, while a MOSFET has a gate, source and drain. ... BJTs are preferred for low current applications, while MOSFETs are for high power functions

Bhāskara's wheel

Bhāskara's wheel was invented in 1150 by Bhāskara II, an Indian mathematician, in an attempt to create a hypothetical perpetual motion machine. The wheel consisted of curved or tilted spokes partially filled with mercury.

borax

Borax, also known as sodium borate, sodium tetraborate, or disodium tetraborate, is an important boron compound, a mineral, and a salt of boric acid. Powdered borax is white, consisting of soft colorless crystals that dissolve in water. Borax, also called sodium tetraborate, is a powdery white mineral that has been used as a cleaning product for several decades. It has many uses: It helps get rid of stains, mold, and mildew around the house. It can kill insects such as ants.

cholera

Cholera is an infectious disease that causes severe watery diarrhea, which can lead to dehydration and even death if untreated. It is caused by eating food or drinking water contaminated with a bacterium called Vibrio cholerae. A bacterial disease causing severe diarrhea and dehydration, usually spread in water.

cross linked polymer

Cross-link is a bond that links one polymer chain to another polymer chain. So cross-linked polymers are polymers that obtained when cross-link bond formed between monomeric units. The cross-linked polymer forms long chains, either branched or linear, that can form covalent bonds between the polymer molecules. Examples of crosslinked polymers include: Polyester fibreglass, polyurethanes used as coatings, adhesives, vulcanized rubber, epoxy resins and many more.

Who was Odysseus?

Depicted here, Odysseus was one of the greatest of the Greek heroes who fought during the Trojan War. Known for his cunning intellect, Odysseus crafted the plan that destroyed the city of Troy and ended the Trojan War. The story of Odysseus begins in Homer's epic poem The Iliad, but his second poem, The Odyssey, relates the tale of Odysseus wandering the seas for ten years as he struggled to return from the Trojan War. Odysseus ruled Ithaca, an island kingdom. Penelope, Odysseus's wife, had borne him a son, Telemachus, just before the events of the Trojan War began to unfold. Odysseus was favored by the goddess Athena for cunning and intellect. Odysseus is also known as Ulysses, which is the Roman form of his name. A prophecy stated Odysseus would stay away from home for a very long time if he joined the Greek army and attacked Troy. Odysseus loved his wife and newborn son. He did not want to leave, so he pretended to be crazy when the Greek army came to call. He yoked a donkey and an ox together and plowed the seashore. One of the Greeks placed Telemachus in the path of Odysseus, who swerved to miss the baby, revealing the farce. Odysseus left Ithaca and his family to fight at Troy. The war with Troy lasted for ten years. Following the death of the Greek champion Achilles, Odysseus devised a plan to enter the city and end the conflict. Here is where the cunning of Odysseus shone through. Odysseus had the Greek army build what came to be known as the Trojan Horse, a giant hollow wooden horse to give the Trojans as an offering of peace. Inside the body of the horse, some of the best Greek warriors hid. The remainder of the Greek army boarded their ships and sailed a short distance away from the city and out of sight. The Trojans rejoiced at the supposed end of the conflict and brought the horse inside the city walls. At night, the Greek warriors emerged from the horse and opened the gates of the city to the waiting Greek army. The city was taken by surprise and destroyed. There is a common saying derived from this event, 'Beware Greeks bearing gifts.' During the sack of the city, the Greek army desecrated the temples and altars of the gods, angering the gods. Upon the departure of the Greek army, a fierce storm caused by the gods scattered the Greek fleet. Odysseus and his men were blown off course, and this began a 10-year struggle to return to Ithaca. Odysseus and his men first landed at the city of Cicones. They attacked and sacked the city, which angered the god Zeus. Zeus caused another storm that blew Odysseus even farther off course and into a realm of monsters, witches and the dead. The first stop on their adventure is to the land of the Lotus-eaters, a people who created food and drink from flowers, but with a drug effect. Several of Odysseus's crew partook of the food presented by the Lotus-eaters and forgot their goal to return home. They wanted to stay among the Lotus-eaters forever. Odysseus had these men dragged to the ships and bound below deck until the ships were safely away from the land of the Lotus-eaters and the men regained their senses. The next stop is one of the most famous adventures on the trip, the meeting of Polyphemus the Cyclops, a 1-eyed giant. Odysseus and his men stopped in the land of the Cyclops and explored the area, finding a large cave. The Cyclops entered the cave with his flock of sheep, blocked the entrance and ate two of Odysseus's men. Odysseus devised a plan to escape the lair of the Cyclops. The next day as the Cyclops was away from the cave, Odysseus had his men create a sharpened stake. The Cyclops returned and began drinking wine and conversing with Odysseus. Odysseus told Polyphemus that his name was Noman. Once the Cyclops fell into a drunken stupor, the men drove the stake through the eye of the Cyclops, as shown on this plate. The Cyclops screamed and called for his brothers to come help, but when they asked what was wrong, Polyphemus answered by saying that Noman was trying to hurt him. They thought there was no danger since no man was hurting Polyphemus and left. The next morning, Odysseus tied his men to the belly of the sheep and they escaped the cave. Polyphemus felt the top of each of the sheep as they left, but he did not feel the men hiding underneath the sheep. The blinding of Polyphemus angered the sea-god Poseidon and further caused the sea to work against Odysseus. Following their escape from the cave of the Cyclops, Odysseus, and his companions came to the land of Aeolus, king of the winds. The king gave Odysseus a sack filled with the contrary winds that would have prevented him from sailing to Ithaca. His crew did not know what was in the sack and assumed it was treasure Odysseus was hoarding for himself. Odysseus was asleep as the ships came in sight of Ithaca. The crew opened the bag of winds, which blew the ships of Odysseus far away from Ithaca to the land of the Laestrygonians, a race of giants and cannibals. The giants destroyed all but one of Odysseus's ships and killed most of his crew. Odysseus and his one remaining ship landed on the island inhabited by the Circe, a witch. Most of Odysseus's crew explored the island and came across the palace of Circe. She invited them in for food and drink. The crew noticed many wild animals roaming peacefully around the palace grounds. The food served by Circe was drugged, and she turned the crew into swine. One of the crew members had remained outside of the palace and, seeing the fate of his companions, ran to tell Odysseus. Odysseus set out to save his companions and was met on the way by the god Hermes. Hermes gave Odysseus an herb to counteract the effects of Circe's drug. Odysseus overpowered Circe, and she agreed to restore his men to human form. Odysseus and his crew remained with Circe for a year before resuming their journey. Circe advised Odysseus to seek the counsel of Tiresias in the underworld on how to return to Ithaca. She also warned him of dangers along the way. Odysseus and his crew sailed to the end of the world to gain access to the underworld. Tiresias, the prophet, revealed to Odysseus the route to Ithaca. Odysseus also visited with some of his dead comrades from the Trojan War, including the heroes Achilles and Ajax. Leaving the underworld, the first danger that Odysseus faced was the Sirens. Sirens were mythical bird-like creatures whose beautiful voices lured men to their deaths. Their island was littered with the bones of old ships and their crews. Odysseus had each of his crew members put wax in their ears to block any noise, but he wanted to hear the song of the Sirens. The crew tied him to the main mast.

Dewey Decimal System

Dewey Decimal System, system for organizing the contents of a library based on the division of all knowledge into 10 groups, with each group assigned 100 numbers.

allies used fake tanks in war

Dummy tanks saw significantly more use during World War II by both the Allies and the Axis. German forces utilized mock tanks prior to the start of the war for practice and training exercises. Their use in military deception was pioneered by British forces, who termed them "spoofs." inflatable tanks in war to make them seem stronger.

what is an eggshell made of?

Eggshell is made almost entirely of calcium carbonate (CaCO3) crystals. It is a semipermeable membrane, which means that air and moisture can pass through its pores. The shell also has a thin outermost coating called the bloom or cuticle that helps keep out bacteria and dust.

what is wire insulation made of

Electrical wires may be insulated with polyethylene, crosslinked polyethylene (either through electron beam processing or chemical crosslinking), PVC, Kapton, rubber-like polymers, oil impregnated paper, Teflon, silicone, or modified ethylene tetrafluoroethylene (ETFE).

Fick's laws of diffusion

Fick's laws of diffusion describe diffusion and were derived by Adolf Fick in 1856. They can be used to solve for the diffusion coefficient, D. Fick's first law can be used to derive his second law which in turn is identical to the diffusion equation. A diffusion process that obeys Fick's laws is called normal diffusion (or Fickian diffusion); Otherwise, it's called Anomalous diffusion (or non-Fickian diffusion).

friability

Friability, the condition of being friable, describes the tendency of a solid substance to break into smaller pieces under duress or contact, especially by rubbing. The opposite of friable is indurate. Substances that are designated hazardous, such as asbestos or crystalline silica, are often said to be friable if small particles are easily dislodged and become airborne, and hence respirable (able to enter human lungs), thereby posing a health hazard.

indenter hardness test

Hardness tests are a measure of resistance to indentation and are notable for being fast, easy, and nondestructive. A force is applied to an indenter, such as a steel ball or diamond pyramid, and the resulting size or depth of the indentation in the surface of the material is measured using a microscope.

heparin

Heparin is an anticoagulant (blood thinner) that prevents the formation of blood clots. Heparin, also known as unfractionated heparin, is a medication and naturally occurring glycosaminoglycan. As a medication it is used as an anticoagulant. Specifically it is also used in the treatment of heart attacks and unstable angina. It is given by injection into a vein or under the skin.

ester

In chemistry, an ester is a chemical compound derived from an acid (organic or inorganic) in which at least one -OH (hydroxyl) group is replaced by an -O-alkyl (alkoxy) group. Usually, esters are derived from a carboxylic acid and an alcohol. Glycerides, which are fatty acid esters of glycerol, are important esters in biology, being one of the main classes of lipids, and making up the bulk of animal fats and vegetable oils. Esters with low molecular weight are commonly used as fragrances and found in essential oils and pheromones. Phosphoesters form the backbone of DNA molecules. Nitrate esters, such as nitroglycerin, are known for their explosive properties, while polyesters are important plastics, with monomers linked by ester moieties. Esters usually have a sweet smell and are considered high-quality solvents for a broad array of plastics, plasticizers, resins, and lacquers.[2] They are also one of the largest classes of synthetic lubricants on the commercial market.

Toughness

In materials science and metallurgy, toughness is the ability of a material to absorb energy and plastically deform without fracturing. One definition of material toughness is the amount of energy per unit volume that a material can absorb before rupturing.

Why LEDs don't produce much heat?

In one sense this is true: LEDs are cool to the touch because they generally don't produce heat in the form of infrared (IR) radiation (unless of course they are IR LEDs). ... However, crucially, heat is produced within the LED device itself, due to the inefficiency of the semiconductor processes that generate light. And not just for fire hazards. Incandescent and CFL bulbs get so hot because most of their energy is being released as heat, not light, making them much more inefficient. Proprietary tests show 100W incandescent lights burning at 335.4 F, CFL lights burning at 179.2 F and LED bulbs burning at 87.2 F High powered lighting LEDs generate light at a much lower running temperatures than the hot filament used in previous generation bulbs. The hottest outside surface of an LED light bulb is often half the temperature of an equivalent brightness Incandescent or Halogen bulb, and around 20% cooler than CFL (Compact fluorescent lamp) bulbs.

Why can't you just swallow insulin?

It would break down in your stomach acid before your body could absorb it.

Liquid-liquid extraction

Liquid-liquid extraction (LLE), also known as solvent extraction and partitioning, is a method to separate compounds or metal complexes, based on their relative solubilities in two different immiscible liquids, usually water (polar) and an organic solvent (non-polar). There is a net transfer of one or more species from one liquid into another liquid phase, generally from aqueous to organic. The transfer is driven by chemical potential, i.e. once the transfer is complete, the overall system of chemical components that make up the solutes and the solvents are in a more stable configuration (lower free energy). The solvent that is enriched in solute(s) is called extract. The feed solution that is depleted in solute(s) is called the raffinate. separation by different densities between liquids

Low carbon vs. high carbon steel

Low carbon steel usually has a carbon content of between 0.05 percent and 0.30 percent, while high carbon steel usually has a carbon content of between 0.55 percent and 0.95 percent. ... However, in pure situations, high carbon steel is extremely strong and works great for products like springs and wires.

law of conservation

Matter is not created nor destroyed in any chemical or physical change. In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time. This law means that energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another.

MEMS

Microelectromechanical systems, also written as micro-electro-mechanical systems and the related micromechatronics and microsystems is the technology of microscopic devices, particularly those with moving parts. It merges at the nanoscale into nanoelectromechanical systems and nanotechnology.

mole density

Molarity (M) indicates the number of moles of solute per liter of solution (moles/Liter) and is one of the most common units used to measure the concentration of a solution. Molarity can be used to calculate the volume of solvent or the amount of solute.

pHEMA

Poly(2-hydroxyethyl methacrylate) (pHEMA) is a polymer that forms a hydrogel in water. Poly (hydroxyethyl methacrylate) (PHEMA) hydrogel for intraocular lens (IOL) materials was synthesized by solution polymerization using 2-hydroxyethyl methacrylate (HEMA) as raw material, ammonium persulfate and sodium pyrosulfite (APS/SMBS) as catalyst, and triethyleneglycol dimethacrylate (TEGDMA) as cross-linking additive. It was invented by Drahoslav Lim and Otto Wichterle for biological use.[1] Together they succeeded in preparing a cross-linking gel which absorbed up to 40% of water, exhibited suitable mechanical properties and was transparent. They patented this material in 1953. Used in contact lenses pHEMA is commonly used to coat cell culture flasks in order to prevent cell adhesion and induce spheroid formation, particularly in cancer research. Older alternatives to pHEMA include agar and agarose gels.

polymer drag reduction

Polymer drag reduction is due to the large elongational viscosity of the polymer solution; this stabilizes the turbulent boundary layer, leading to less turbulent energy generation and hence less dissipation. Drag-reducing polymer solution flows behave like viscoelastic characteristics. In 1948 Toms discovered by experiments that the addition of a small amount of polymer into a turbulent Newtonian solvent (parts per million by weight), which results in a Non-Newtonian fluid solution, can reduce the skin frictional drag on a stationary surface by up to 80% . This technology has been successfully implemented to reduce pumping cost for oil pipelines, to increase the flow rate in fire fighting equipment and to help irrigation and drainage (Sellin & Ollis, 1980; Khalil et al., 2002). It also has potential applications in the design of ship and submarine hulls to achieve an increased speed and reduced energy cost.

What is the difference between real and ideal gas?

Real gas: They are non-hypothetical gases whose molecules occupy space and have interactions; consequently, they adhere to gas laws. Ideal gas: They are hypothetical gases whose molecules occupy negligible space and have no interaction; consequently, they obeys the gas law exactly. Distinguish between Real gas and ideal gas: 1.Ideal gas has no definite volume while real gas has definite volume. 2.Ideal gas has no mass whereas real gas has mass. 3.Collision of ideal gas particles is elastic while non-elastic for real gas. energy involved during collision of particles in ideal gas. Collision of particles in real gas has attracting energy. 5.Pressure is high in ideal gas compared to real gas. 6.Ideal gas follows the equation PV=nRT. Real gas follows the equation (P + a/V2) (V - b) = nRT. Any gas that exists is a real gas. Nitrogen, oxygen, carbon dioxide, carbon monoxide, helium etc. ... Real gases have small attractive and repulsive forces between particles and ideal gases do not. Real gas particles have a volume and ideal gas particles do not

Reynolds number formula

Reynolds number is used to predict both where and at what scale in the flow this transition will happen for any given fluid in any given flow situation. Reynolds number is an important dimensionless quantity in fluid mechanics used to help predict flow patterns in different fluid flow-situations. dimensionless: there are no units attached to the number high reynolds number = turbulent flow low reynolds number = laminar flow

Shoe-fitting fluoroscope

Shoe-fitting fluoroscopes, also sold under the names X-ray Shoe Fitter, Pedoscope and Foot-o-scope, were X-ray fluoroscope machines installed in shoe stores from the 1920s until about the 1970s in the United States, Canada, United Kingdom, South Africa, Germany and Switzerland At the beginning of the 1930s, Bally was the first company to import pedoscopes into Switzerland from the UK. In the second half of the 20th century, growing awareness of radiation hazards and increasingly stringent regulations forced their gradual phasing out.

is steel an alloy?

Steel is called as an alloy because it is the combination iron(main constituent) and various elements like carbon, phosphorus, silicon, manganese, chromium etc in very little proportion. These elements tend to enhance various material properties like hardness, ductility, corrosion resistance, wear resistance of steel.

stress vs strain

Stress is the total force acting on crustal rocks per unit of area Strain is the deformation of materials in response to stress

Stripping (chemistry)

Stripping is a physical separation process where one or more components are removed from a liquid stream by a vapor stream. In industrial applications the liquid and vapor streams can have co-current or countercurrent flows. Stripping is usually carried out in either a packed or trayed column. Stripping works on the basis of mass transfer. The idea is to make the conditions favorable for the component, A, in the liquid phase to transfer to the vapor phase. This involves a gas-liquid interface that A must cross. The total amount of A that has moved across this boundary can be defined as the flux of A, NA. Stripping is mainly conducted in trayed towers (plate columns) and packed columns, and less often in spray towers, bubble columns, and centrifugal contactors. Trayed towers consist of a vertical column with liquid flowing in the top and out the bottom. The vapor phase enters in the bottom of the column and exits out of the top. Inside of the column are trays or plates. These trays force the liquid to flow back and forth horizontally while the vapor bubbles up through holes in the trays. The purpose of these trays is to increase the amount of contact area between the liquid and vapor phases.

ceramic vs glass

The major distinction between glass and ceramics is that both have diversity in their structure. Ceramics have crystalline, semi-crystalline or non-crystalline nuclear structures and glass has a non-crystalline thermonuclear structure. There are also made ceramic elements such as diamond, SiC, Si3N4, and more.

fatigue strength

The maximum stress level that a material can sustain without failing, for some specified number of cycles. Fatigue strength is the highest stress that a material can withstand for a given number of cycles without breaking. Fatigue strength is affected by environmental factors, such as corrosion. The maximum stress that can be applied for a certain number of cycles without fracture is the fatigue strength. The Fatigue limit also known as the endurance limit or fatigue strength is the stress level below which an infinite number of loading cycles can be applied to a material without causing fatigue failure. Ferrous alloys and titanium alloys have a distinct limit. Other structural metals such as aluminium and copper do not have a distinct limit and will eventually fail even from small stress amplitudes. In these cases, the term endurance strength is used. Endurance strength is defined as the maximum value of completely reversed bending stress that a material can withstand for a finite number of cycles without a fatigue failure.

forced convection

The movement of a fluid by a fan or a pump, in order to force heat exchange. mechanical turbulence using electricity/energy to produce convection

modulus of elasticity

The ratio of the increment of some specified form of stress to the increment of some specified form of strain, such as Young's modulus, the bulk modulus, or the shear modulus. Also known as coefficient of elasticity, elasticity modulus, elastic modulus. An elastic modulus is a quantity that measures an object or substance's resistance to being deformed elastically when a stress is applied to it. The elastic modulus of an object is defined as the slope of its stress-strain curve in the elastic deformation region: A stiffer material will have a higher elastic modulus.

yield stress

The stress at which a material begins to deform plastically. The yield point is the point on a stress-strain curve that indicates the limit of elastic behavior and the beginning plastic behavior.

what metal is used in braces for teeth?

The traditional metal braces are made of stainless steel. The arch wires that go into the braces are made of different types of material. Some of the wires placed early on in the orthodontic treatment are made of an alloy of nickel, copper and titanium, some of the wires are made of titanium and molybdenum.

pharmaceutical waste

There are generally two types of pharmaceutical waste. One is industrial waste produced by the plants that manufacture the pharmaceuticals and the other is the waste that end users or patients create when they dispose of their old prescriptions. Although both can be hazardous to the environment the second type is probably more insidious since it is difficult to regulate and come into the water table in residential areas. Industrial waste is hopefully regulated more tightly although there are many cases where certain agents have entered into the ecosystem.

billiard balls used to be flammable

There was a time when taking a perfect shot in a game of billiards could cause the ball to explode. That's because the balls were made of celluloid, an early plastic that was, unfortunately, combustible. It was patented on this day in 1869, just a few years after the first human-made plastic, Parkesine. Celluloids are a class of compounds created from nitrocellulose and camphor, with added dyes and other agents. Generally considered the first thermoplastic a transparent flammable plastic made in sheets from camphor and nitrocellulose, formerly used for cinematographic film.

Titanium

Titanium is a chemical element with the symbol Ti and atomic number 22. It is a lustrous transition metal with a silver color, low density, and high strength. Titanium is resistant to corrosion in sea water, aqua regia, and chlorine Titanium metal is used as an alloying agent with metals including aluminum, iron, molybdenum and manganese. Alloys of titanium are mainly used in aerospace, aircraft and engines where strong, lightweight, temperature-resistant materials are needed. There are several things that are special about titanium. ... Titanium metal is a very durable metal for engineering applications because this metal is corrosion-resistant and also this metal is very strong and very light. It is 40% lighter than steel but as strong as high-strength steel

Shell and Tube Heat Exchanger

Type of evaporator similar in operation to the shell and tube condenser. The refrigerant is expanded into a shell enclosing the tube through which the water flows. Baffles are added to increase heat transfer by making the fluid take a longer route and producing turbulence

Vulcanization

Vulcanization is a chemical process, invented by Charles Goodyear, used to harden rubber. Vulcanization traditionally referred to the treatment of natural rubber with sulfur and this remains the most common example, however the term has also grown to include the hardening of other (synthetic) rubbers via various means. Examples include silicone rubber via room temperature vulcanizing and chloroprene rubber (neoprene) using metal oxides. Vulcanization can therefore be defined as the curing of elastomers; with the terms 'vulcanization' and 'curing' sometimes used interchangeably in this context. It works by forming cross-links between sections of polymer chain which results in increased rigidity and durability, as well as other changes in the mechanical and electrical properties of the material. Vulcanization, in common with the curing of other thermosetting polymers, is generally irreversible. The word vulcanization is derived from Vulcan, the Roman god of fire and forge. Natural rubber is a polymer of isoprene (also known as 2-methylbuta-1,3-diene) with the chemical formula (C5H8)n

reverse osmosis

a process of desalination in which water is forced through a thin semi-permeable membrane at high pressure

aerogel

a solid material of extremely low density, produced by removing the liquid component from a conventional gel. Despite the name, aerogels are solid, rigid, and dry materials that do not resemble a gel in their physical properties: the name comes from the fact that they are made from gels. Pressing softly on an aerogel typically does not leave even a minor mark; pressing more firmly will leave a permanent depression. Pressing extremely firmly will cause a catastrophic breakdown in the sparse structure, causing it to shatter like glass (a property known as friability), although more modern variations do not suffer from this. Despite the fact that it is prone to shattering, it is very strong structurally. Its impressive load-bearing abilities are due to the dendritic microstructure, in which spherical particles of average size 2-5 nm are fused together into clusters. These clusters form a three-dimensional highly porous structure of almost fractal chains, with pores just under 100 nm. The average size and density of the pores can be controlled during the manufacturing process. Aerogel is a material that is 99.8% air. Aerogels have a porous solid network that contains air pockets, with the air pockets taking up the majority of space within the material. The lack of solid material allows aerogel to be almost weightless. Aerogels are good thermal insulators because they almost nullify two of the three methods of heat transfer - conduction (they are mostly composed of insulating gas) and convection (the microstructure prevents net gas movement). They are good conductive insulators because they are composed almost entirely of gases, which are very poor heat conductors. (Silica aerogel is an especially good insulator because silica is also a poor conductor of heat; a metallic or carbon aerogel, on the other hand, would be less effective.) They are good convective inhibitors because air cannot circulate through the lattice. Aerogels are poor radiative insulators because infrared radiation (which transfers heat) passes through them. Owing to its hygroscopic nature, aerogel feels dry and acts as a strong desiccant. People handling aerogel for extended periods should wear gloves to prevent the appearance of dry brittle spots on their skin. The slight color it does have is due to Rayleigh scattering of the shorter wavelengths of visible light by the nano-sized dendritic structure. This causes it to appear smoky blue against dark backgrounds and yellowish against bright backgrounds. Aerogels by themselves are hydrophilic, and if they absorb moisture they usually suffer a structural change, such as contraction, and deteriorate, but degradation can be prevented by making them hydrophobic, via a chemical treatment. Aerogels with hydrophobic interiors are less susceptible to degradation than aerogels with only an outer hydrophobic layer, even if a crack penetrates the surface.

polyurethane

a synthetic resin manufactured from polymers joined by urethane used in adhesives, carpet padding, plastics, etc. Also used in heart valves Polyurethane (PUR and PU) is a polymer composed of organic units joined by carbamate (urethane) links. While most polyurethanes are thermosetting polymers that do not melt when heated, thermoplastic polyurethanes are also available. Polyurethane polymers are traditionally and most commonly formed by reacting a di- or triisocyanate with a polyol. Since polyurethanes contain two types of monomers, which polymerise one after the other, they are classed as alternating copolymers. Both the isocyanates and polyols used to make polyurethanes contain, on average, two or more functional groups per molecule. Polyurethanes are used in the manufacture of high-resilience foam seating, rigid foam insulation panels, microcellular foam seals and gaskets, durable elastomeric wheels and tires (such as roller coaster, escalator, shopping cart, elevator, and skateboard wheels), automotive suspension bushings, electrical potting compounds, high-performance adhesives, surface coatings and surface sealants, synthetic fibers (e.g., Spandex), carpet underlay, hard-plastic parts (e.g., for electronic instruments), condoms, and hoses.

creep strength

ability of a metal to withstand a constant weight or force at elevated temperatures In materials science, creep (sometimes called cold flow) is the tendency of a solid material to move slowly or deform permanently under the influence of persistent mechanical stresses. It can occur as a result of long-term exposure to high levels of stress that are still below the yield strength of the material. Creep is more severe in materials that are subjected to heat for long periods and generally increases as they near their melting point.

murphys law

anything that can go wrong will go wrong

Bernoulli's Principle

as the velocity of a fluid increases, the pressure exerted by the fluid decreases In fluid dynamics, Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in static pressure or a decrease in the fluid's potential energy.

axial fin tube heat exchanger

better heat transfer than concentric tube

radial fin heat exchanger

better heat transfer than concentric tube

convective heat transfer coefficient

coefficient that takes into account the properties of the fluid, velocity of fluid, geometry and surface roughness of the object in contact with the fluid The convective heat transfer coefficient, h, can be defined as: The rate of heat transfer between a solid surface and a fluid per unit surface area per unit temperature difference. The convective heat transfer coefficient is dependent upon the physical properties of the fluid and the physical situation.

angstrom

10^-10 a unit of length equal to one hundred-millionth of a centimeter, 10−10 meter, used mainly to express wavelengths and interatomic distances.

Saline

containing or impregnated with salt. Saline, also known as saline solution, is a mixture of sodium chloride in water and has a number of uses in medicine. Applied to the affected area it is used to clean wounds, help remove contact lenses, and help with dry eyes.

strain

deformation of materials in response to stress

accelerometer

Feature in smartphones and tablets that rotates the screen when the device is physically rotated. An accelerometer is a device that measures proper acceleration. Proper acceleration, being the acceleration (or rate of change of velocity) of a body in its own instantaneous rest frame, is not the same as coordinate acceleration, being the acceleration in a fixed coordinate system. For example, an accelerometer at rest on the surface of the Earth will measure an acceleration due to Earth's gravity, straight upwards (by definition) of g ≈ 9.81 m/s2. By contrast, accelerometers in free fall (falling toward the center of the Earth at a rate of about 9.81 m/s2) will measure zero. Accelerometers have multiple applications in industry and science. Highly sensitive accelerometers are components of inertial navigation systems for aircraft and missiles. Accelerometers are used to detect and monitor vibration in rotating machinery. Accelerometers are used in tablet computers and digital cameras so that images on screens are always displayed upright. Accelerometers are used in drones for flight stabilisation. Coordinated accelerometers can be used to measure differences in proper acceleration, particularly gravity, over their separation in space; i.e., gradient of the gravitational field. This gravity gradiometry is useful because absolute gravity is a weak effect and depends on local density of the Earth which is quite variable.

isentropic flow

Flow that is both adiabatic and reversible In fluid dynamics, an isentropic flow is a fluid flow that is both adiabatic and reversible. That is, no heat is added to the flow, and no energy transformations occur due to friction or dissipative effects. can go back and forth indefinitely

How does friction relate to velocity?

Higher velocity = higher friction

diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration. diffusion gradient

bernoulli's equation

P1 +1/2 ρv_1^2+ρgh_1= P_2+1/2 ρv_2^2+ρgh_2 P : absolute pressure of the fluid v: linear speed h: height of the fluid essentially just stating that the energy at one point equals the energy at another point. in the picture there is a venturi where if conditions are ideal velocity will increase causing a pressure drow on the other side

types of stress engineering

There are six types of stress: compression, tension, shear, bending, torsion, and fatigue. Each of these stresses affects an object in different ways and is caused by the internal forces acting on the object.

forward biased and reverse biased

When the polarity of the battery is such that current is allowed to flow through the diode, the diode is said to be forward-biased. Conversely, when the battery is "backward" and the diode blocks current, the diode is said to be reverse-biased.

whiteware

a class of ceramic products that include porcelain, china, pottery, earthenware, stoneware, and vitreous tile, are usually but not necessarily white, and consist typically of clays, feldspar, potter's flint, and whiting.

Pendentive

a curved triangle of vaulting formed by the intersection of a dome with its supporting arches.

real gas

a gas that does not behave completely according to the assumptions of the kinetic-molecular theory Any gas that exists is a real gas. Nitrogen, oxygen, carbon dioxide, carbon monoxide, helium etc. ... Real gases have small attractive and repulsive forces between particles and ideal gases do not. Real gas particles have a volume and ideal gas particles do not

isochoric process

constant volume

Moody chart

predictions equations for laminar and turbulent flow In engineering, the Moody chart or Moody diagram is a graph in non-dimensional form that relates the Darcy-Weisbach friction factor fD, Reynolds number Re, and surface roughness for fully developed flow in a circular pipe. It can be used to predict pressure drop or flow rate down such a pipe.

Raffinate

the feed solution minus the extracted solute In chemical separation terminology, the raffinate (from French raffiner, to refine) is a product which has had a component or components removed. The product having the removed materials is referred to as the extract. For example, in solvent extraction, the raffinate is the liquid stream which remains after solutes from the original liquid are removed through contact with an immiscible liquid. In metallurgy, raffinating refers to a process in which impurities are removed from liquid material.

Imposter Syndrome

the feeling of people from the lower classes who succeed in life that they have fooled others into thinking that they are deserving of recognition, respect, and acceptance Imposter syndrome can be defined as a collection of feelings of inadequacy that persist despite evident success. 'Imposters' suffer from chronic self-doubt and a sense of intellectual fraudulence that override any feelings of success or external proof of their competence

interfacial

where two surfaces or planes meet relating to or situated at an interface "an interfacial layer"

modulus

(physics) a coefficient that expresses how much of a specified property is possessed by a specified substance

On June 18, 1964, black and white protesters jumped into the whites-only pool at the Monson Motor Lodge in St. Augustine, Fla. In an attempt to force them out, the owner of the hotel poured muriatic acid (HCl) into the pool.

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gigapascal to psi

1 gP = 145,000 psi

distillation column

A cylindrical tower consisting of a series of trays or packing that provide a contact point for vapor and liquid. The contact between the vapor and liquid in the column results in the separation of components in the mixture based on the differences in boiling points.

Charpy impact test

A destructive test of impact resistance, consisting of placing a test coupon in a horizontal position between two supports, then applying a blow of known magnitude. If the specimen does not break, a new specimen is put in position and the magnitude is increased until the specimen breaks. The Charpy impact test, also known as the Charpy V-notch test, is a standardized high strain-rate test which determines the amount of energy absorbed by a material during fracture. Using a pendulum to break a material

Non-Newtonian Fluid

A form of matter that will turn into a solid when pressure is exerted on it, and will turn into a liquid when little or no pressure is exerted on it. a fluid where the viscosity changes under stress. e.g. you step on it and it becomes firm

Stoneware

A high-fire clay. Stoneware is waterproof even without glaze; the resulting ware is sturdier than earthenware. high temperature fired clay

Hydrogel

A hydrogel is a three-dimensional (3D) network of hydrophilic polymers that can swell in water and hold a large amount of water while maintaining the structure due to chemical or physical cross-linking of individual polymer chains Hydrogels are used to make soft contact lenses, nappies, wound dressings and drug delivery systems. How is a Hydrogel used for a Wound Dressing? A wound dressing is put over a cut in the skin to help the skin heal.

Solvent

A liquid substance capable of dissolving other substances A solvent is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. The quantity of solute that can dissolve in a specific volume of solvent varies with temperature.

Refractory

A refractory material or refractory is a heat-resistant material: that is, a mineral that is resistant to decomposition by heat, pressure, or chemical attack, most commonly applied to a mineral that retains strength and form at high temperatures.

glass-ceramics

A special class of materials obtained by forming a glass and then heat treating it to form small crystals. Glass-ceramics have an amorphous phase and one or more crystalline phases and are produced by a so-called "controlled crystallization" in contrast to a spontaneous crystallization, which is usually not wanted in glass manufacturing. Glass-ceramics have the fabrication advantage of glass, as well as special properties of ceramics. When used for sealing, some glass-ceramics do not require brazing but can withstand brazing temperatures up to 700 °C. Glass-ceramics usually have between 30% [m/m] and 90% [m/m] crystallinity and yield an array of materials with interesting properties like zero porosity, high strength, toughness, translucency or opacity, pigmentation, opalescence, low or even negative thermal expansion, high temperature stability, fluorescence, machinability, ferromagnetism, resorbability or high chemical durability, biocompatibility, bioactivity, ion conductivity, superconductivity, isolation capabilities, low dielectric constant and loss, high resistivity and break-down voltage. These properties can be tailored by controlling the base-glass composition and by controlled heat treatment/crystallization of base glass. In manufacturing, glass-ceramics are valued for having the strength of ceramic but the hermetic sealing properties of glass.

steady-state

A state in which members of a population die as quickly as new members are born. The definition of a steady-state is an unchanging condition, system or physical process that remains the same even after transformation or change. When you have a chemical mix that has certain properties, and the mix retains those properties even after you add a change-agent, this is an example of a steady-state.