Vocab v67

The FDIC insures all accounts per person and per bank up to:

$250,000 This is known as deposit insurance. To get more than $250k insurance, open a new account at another bank.

ravage

(v.) to destroy, lay waste, ruin; (n.) ruinous damage, destruction

asterisk

****** figure used to indicate an omission or a footnote

"Rent is the most you will ever spend on living arrangements per month. A mortgage is the minimum."

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"What hath God wrought" the official first Morse code message transmitted in the US on May 24, 1844, to officially open the Baltimore-Washington telegraph line.

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A drop in interest rates from 5 percent to 4 percent requires an 18 percent increase in the amount saved each year in order to reach the same goal over 30 years.

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An economy results as millions of individuals attempt to satisfy their unlimited wants.

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As I writhed under it, I would at times feel that learning to read had been a curse rather than a blessing. It had given me a view of my wretched condition, without the remedy. It opened my eyes to the horrible pit, but to no ladder upon which to get out. In moments of agony, I envied my fellow-slaves for their stupidity.

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Because goods and services are produced using scarce resources, they are themselves scarce.

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Goods and services that are truly free are not the subject matter of economics. Without scarcity, there would be no economic problem and no need for prices.

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I was broken in body, soul, and spirit. My natural elasticity was crushed, my intellect languished, the disposition to read departed, the cheerful spark that lingered about my eye died; the dark night of slavery closed in upon me; and behold a man transformed into a brute!

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In egypt property tax is not imposed until a building is complete. To avoid such taxes builders never finish the job; multistory dwellings are usually missing the top floor.

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It is not the employer who pays the wages, the employer only handles the money. It is the product that pays the wages.

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Next, consider job hopping. Every hop provides a chance to increase your income. Don't buy into the myth of working hard for that one employer who will someday realize your worth. They won't. They'll just keep dogging you and underpaying you until you snap.

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One person's spending is another person's income.

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People generally don't take action on something unless they're being directly affected. That's also one of the reasons that environmental issues and modern day slavery still exist. I'd say that's the reason most world's problems exist.

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People with pain disorder experience pain that medical doctors cannot explain. A person may distinctly feel a throbbing backache, yet doctor after doctor cannot give a physical reason for it. Clinicians conclude that these patients' pain stems from their psyches rather than physical conditions. We know of course the mind is intertwined with the body. If there are no structural reasons for a backache, like a slipped disk or muscle injury, pain may originate in an active perception by the mind (i.e. nervous system) as opposed to passive reception of content.

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Practicing anything repeatedly without changing technique will not aid in developing the skill.

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The hours were long and the rewards were unpredictable.

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U.S. railroads still play a major role in the nation's freight shipping. They carried 750 billion ton-miles by 1975 which doubled to 1.5 trillion ton-miles in 2005.

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Voltage = PSIG Amperage = GPM Water analogy

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We can sell our time as labor, or we can spend our time doing other things.

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You may have heard the expression "There is no such thing as a free lunch." The is no free lunch because all goods and services involve a cost to someone. The lunch may seem free to you, but it draws scarce resources away from the production of other goods and services, and whoever provides a free lunch often expects something in return. A Russian proverb makes a similar point but with a bit more bite: "The only place you find free cheese is in a mousetrap." Albert Einstein once observed, "Sometimes one pays the most for things one gets for nothing."

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finding nuance in trivial encounters

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Pontiac's Rebellion

1763 - An Indian uprising after the French and Indian War, led by an Ottawa chief named Pontiac. They opposed British expansion into the western Ohio Valley and began destroying British forts in the area. The attacks ended when Pontiac was killed. Brutal battle where the British attempted to introduces smallpox into indian communities through infected blankets and indians deliberately poisoning british troops drinking water by putting rotten meat in springs upriver from british camps.

When was the civil war?

1861-1865

Tuskegee Airmen

332 Fighter Group famous for shooting down over 200 enemy planes. Consisted of all African American pilots who trained at the Tuskegee flying school. In all, 992 pilots were trained in Tuskegee from 1941-1946. 355 were deployed overseas, and 84 lost their lives.[45][73] The toll included 68 pilots killed in action or accidents, 12 killed in training and non-combat missions[74] and 32 captured as prisoners of war.[75][76] 179 bomber escort missions,[46] with a good record of protection,[75] losing bombers on only seven missions and a total of only 27, compared to an average of 46 among other 15th Air Force P-51 groups 112 enemy aircraft destroyed in the air, another 150 on the ground[46] and 148 damaged. This included three Me-262 jet fighters shot down 950 rail cars, trucks and other motor vehicles destroyed (over 600 rail cars)

Erie Canal

A canal between the New York cities of Albany and Buffalo, completed in 1825. The canal, considered a marvel of the modern world at the time, allowed western farmers to ship surplus crops to sell in the North and allowed northern manufacturers to ship finished goods to sell in the West. 364 miles long, 40 feet wide, 14 feet deep, completed in 8 years. The canal was built largely with raw manpower provided by Irishmen using primitive tools with very little compensation for their hard work. In a time when bulk goods were limited to pack animals (a 250-pound (113 kg) maximum[4]), and there were no railways, water was the most cost-effective way to ship bulk goods. It was faster than carts pulled by draft animals and cut transport costs by about 95%.[8] The canal gave New York City's port an incomparable advantage over all other U.S. port cities and ushered in the state's 19th century political and cultural ascendancy.[2] The canal fostered a population surge in western New York and opened regions farther west to settlement. It was enlarged between 1834 and 1862. The canal's peak year was 1855, when 33,000 commercial shipments took place. In 1918, the western part of the canal was enlarged to become part of the New York State Barge Canal, which also extended to the Hudson River running parallel to the eastern half of the Erie Canal. In 2000, the United States Congress designated the Erie Canalway National Heritage Corridor[9] to recognize the national significance of the canal system as the most successful and influential human-built waterway and one of the most important works of civil engineering and construction in North America.[9] The canal has been mainly used by recreational watercraft since the retirement of the last large commercial ship, Day Peckinpaugh, in 1994. The canal saw a recovery in commercial traffic in 2008.[10]

Transcendentalism

A core belief is in the inherent goodness of people and nature, [1] and while society and its institutions have corrupted the purity of the individual, people are at their best when truly "self-reliant" and independent.

glass ceiling

A glass ceiling is a metaphor used to represent an invisible barrier that keeps a given demographic from rising beyond a certain level in a hierarchy. an unknown variable or thing that prevents something from happening or moving forward

pantomime

A performance using gestures and body movements without words Acting without words

sect

A relatively small group that has broken away from an established thing.

Iwo Jima and Okinawa

After Germany surrendered in WW2, Japan chose to fight on. Iwo Jima and Okinawa were the last two strategically important islands held by the Japanese in the War in the Pacific. The Japanese lost more than 130,000 men defending the islands they considered as the gateway to their homeland, and the Americans lost more than 19,000 soldiers.

nonintercourse act

An 1809 law that allowed Americans to carry on trade with all nations except Britain and France. Trade could begin again with France and Britain once they began respecting America's neutral trading rights. France and Britain were in a war at the time this was put in place. France's leader Napoleon decided to respect america's neutrality rights whereupon trade resumed. However our current president James Madison vehemently prohibited trade with Britain causing them to go into an economic depression. lol

Sociable Weaver (Philetairus socius)

As their name suggests, these birds nest and brood in groups. They build a gigantic nest-within-a-nest structure attached to trees and poles. A compound nest can house over 100 breeding pairs, each contributing to its construction, maintenance and repair. Living in groups means someone is always on the lookout for danger.

Benedict Arnold

Brigadier General Benedict Arnold was an American-born senior officer of the British Army who commanded the American Legion in the later part of the Revolutionary War. He is best known for his defection from the Continental Army to the British side of the conflict in 1780. Arnold was an american hero that the British paid to change sides during the revolutionary war. One of the largest traitors in history.

fetch execute cycle

During the fetch execute cycle, the computer retrieves a program instruction from its memory. It then establishes and carries out the actions that are required for that instruction. The cycle of fetching, decoding, and executing an instruction is continually repeated by the CPU whilst the computer is turned on.

Echinacea

Echinacea is a genus, or group of herbaceous flowering plants in the daisy family. The genus Echinacea has ten species, which are commonly called coneflowers. They are found only in eastern and central North America, where they grow in moist to dry prairies and open wooded areas. Echinacea angustifolia was widely used by the North American indigenous peoples as folk medicine.[28] According to Wallace Sampson, its modern use for the common cold began when a Swiss herbal supplement maker was told that Echinacea was used for cold prevention by Native American tribes who lived in the area of South Dakota.[29] Some Plains tribes did use echinacea for cold symptoms. The Kiowa used it for coughs and sore throats, the Cheyenne for sore throats, the Pawnee for headaches, and many tribes including the Lakota used it as a pain medication.[30]

Endometriosis

Endometriosis is an often painful disorder in which tissue similar to the tissue that normally lines the inside of your uterus — the endometrium — grows outside your uterus. Endometriosis most commonly involves your ovaries, fallopian tubes and the tissue lining your pelvis.

Endosome

Endosomes are a collection of intracellular sorting organelles in eukaryotic cells. They are part of endocytic membrane transport pathway originating from the trans Golgi network. Molecules or ligands internalized from the plasma membrane can follow this pathway all the way to lysosomes for degradation or can be recycled back to the plasma membrane in the endocytic cycle. Molecules are also transported to endosomes from the trans Golgi network and either continue to lysosomes or recycle back to the Golgi apparatus.

Hemozoin

Haemozoin is a disposal product formed from the digestion of blood by some blood-feeding parasites. These hematophagous organisms such as malaria parasites (Plasmodium spp.), Rhodnius and Schistosoma digest haemoglobin and release high quantities of free heme, which is the non-protein component of hemoglobin. Heme is a prosthetic group consisting of an iron atom contained in the center of a heterocyclic porphyrin ring. Free heme is toxic to cells, so the parasites convert it into an insoluble crystalline form called hemozoin. In malaria parasites, hemozoin is often called malaria pigment.

creep

High-pressure valve seats that leak result in creep, or rising pressure, on the working side of the regulator. This usually occurs when the gas pressure is set but no gas is flowing. If the leakage at the seat is severe, then the maximum safe pressure can be exceeded on the working side, resulting in damage to the diaphragm, gauge, hoses, or other equipment.

Olfactory receptor neuron

Humans have between 10 and 20 million olfactory receptor neurons.[3] In vertebrates, ORNs are bipolar neurons with dendrites facing the external surface of the cribriform plate with axons that pass through the cribriform foramina with terminal end at olfactory bulbs. The ORNs are located in the olfactory epithelium in the nasal cavity. The cell bodies of the ORNs are distributed among all three of the stratified layers of the olfactory epithelium. ORs, which are located on the membranes of the cilia have been classified as a complex type of ligand-gated metabotropic channels.[6] There are approximately 1000 different genes that code for the ORs, making them the largest gene family. An odorant will dissolve into the mucus of the olfactory epithelium and then bind to an OR. ORs can bind to a variety of odor molecules, with varying affinities. The difference in affinities causes differences in activation patterns resulting in unique odorant profiles.[7][8] The activated OR in turn activates the intracellular G-protein, GOLF (GNAL), adenylate cyclase and production of cyclic AMP (cAMP) opens ion channels in the cell membrane, resulting in an influx of sodium and calcium ions into the cell, and an efflux of chloride ions. This influx of positive ions and efflux of negative ions causes the neuron to depolarize, generating an action potential.

interchangeable parts

Identical components that can be used in place of one another in manufacturing. This makes it so you don't have to throw away the whole device when something breaks.

charging interest is banned under islamic law

In Islamic finance, riba refers to interest charged on loans or deposits. Religious practice forbids riba, even at low interest rates, as both illegal and unethical or usurious. Islamic banking has provided several work-arounds to accommodate financial transactions with charging explicit interest.

marginal

Incremental, additional, or extra; used to describe a change in an economic variable e.g. taxes

do yeast eat flour?

Instead, it starts to eat: sugar (sucrose and fructose) is its favorite food. If there is sugar in the dough, that's what the yeast eats first; once that's gone, yeast converts the starch in flour into sugar; thus flour is capable of providing yeast with a continuous food source.

Interpass temperature

Interpass temperature is the temperature of the metal during welding. The interpass temperature is given as a minimum and maximum. The minimum temperature is usually the same as the preheat temperature. If the plate cools below this temperature during welding, it should be reheated. The maximum temperature may be specified to keep the plate below a certain phase change temperature for the mild steel used in these practices. The maximum interpass temperature occurs when the weld bead cannot be controlled because of a slow cooling rate. When this happens, the plate should be allowed to cool down, but not below the minimum interpass temperature.

How GDP is calculated

It is based on all final goods and services. E.g. if a grocer buys a can of tuna for $1 and sells it for $1.50, only $1.50 goes towards GDP. If both went towards GDP this would be a double counting problem which is common.

kerf (welding)

Kerf is defined as the width of material that is removed by a cutting process. Affecting factors: ● Standoff distance—The closer the torch nozzle tip is to the work, the narrower the kerf will be, Figure 8-29. ● Orifice diameter—Keeping the diameter of the nozzle orifice as small as possible will keep the kerf smaller. ● Power setting—Too high or too low of a power setting will cause an increase in the kerf width. ● Travel speed—As the travel speed is increased, the kerf width will decrease; however, the bevel on the sides and the dross formation will increase if the speeds are excessive.

microsociology vs macrosociology

Macrosociology is a large-scale approach to sociology, emphasizing the analysis of social systems and populations at the structural level, often at a necessarily high level of theoretical abstraction. In contrast, microsociology focuses on the individual social agency.

mirror touch synesthesia

People with mirror-touch synesthesia, another cognitive condition, experience sensations they observe in other people. If they see someone else slapped on the cheek, they experience matching cheek pain. You could say they have a high level of empathy. Their pain does not reflect the truth of their own corporeal state but their visual understanding of another person's.

physical capital vs human capital

Physical capital implies the non-human assets of the company, such as plant and machinery, tools and equipment, office supplies etc. that help in the process of production. Human capital refers to stock of knowledge, talent, skills and abilities brought in by the employee, to the organization.

selling of indulgences

Practice of popes using their authority to limit the time a person's soul spent in purgatory, in exchange for cash. the og charlatan scam One particularly well-known Catholic method of exploitation in the Middle Ages was the practice of selling indulgences, a monetary payment of penalty which, supposedly, absolved one of past sins and/or released one from purgatory after death.

normative

Something pertaining to norms — something normal or typical — can be described as normative. Temper tantrums, whining, and even hitting are all normative behaviors — if you're three.

Burr-Hamilton duel

The Burr-Hamilton duel was a duel fought at Weehawken, New Jersey, between Vice President Aaron Burr and Alexander Hamilton, the former Secretary of the Treasury. It occurred early in the morning of July 11, 1804 and was the culmination of a long and bitter rivalry between the two men. Hamilton shot first, deliberately firing a shot into the air perhaps as a form of protesting duels. He was soon after killed. At the time of the duel, Burr was vice president and soon after lost all political respectability. Alexander Hamilton was an American statesman, politician, legal scholar, military commander, lawyer, banker, and economist. He was one of the Founding Fathers of the United States. Burr was the VP to Thomas Jefferson, 3rd president.

Trail of Tears

The Cherokee Indians were forced to leave their lands. They traveled from North Carolina and Georgia through Tennessee, Kentucky, Illinois, Missouri, and Arkansas-more than 800 miles (1,287 km)-to the Indian Territory. More than 4, 00 Cherokees died of cold, disease, and lack of food during the 116-day journey.

solvency

The ability of a company to pay interest as it comes due and to repay the balance of debt due at its maturity. The solvency ratio is a key metric used to measure an enterprise's ability to meet its debt obligations and is used often by prospective business lenders. The solvency ratio indicates whether a company's cash flow is sufficient to meet its short-and long-term liabilities. The lower a company's solvency ratio, the greater the probability that it will default on its debt obligations.

ETF vs index fund

The biggest difference between ETFs and index funds is that ETFs can be traded throughout the day like stocks, whereas index funds can be bought and sold only for the price set at the end of the trading day.

land lust

The desire or craving for land White land lust lead to the evisceration of the native american population.

Stono Rebellion (1739)

The most serious slave rebellion in the the colonial period; inspired in part by Spanish officials' promise of freedom for American slaves who escaped to Florida. *Historical Significance:* Led to the Negro Act of 1740 prohibiting slaves from growing their own food, assembling in groups, earning money, or learning to read and making it more difficult to free slaves.

malthusian theory

The theory that population grows faster than food supply

phosphorescence vs fluorescence

There are three main forms of luminescence at play: fluorescence, phosphorescence and chemiluminescence. Fluorescence and phosphorescence are two forms of photoluminescence. In photoluminescence, a substance's glow is triggered by light, in contrast to chemiluminescence, where the glow is caused by a chemical reaction. Both fluorescence and phosphorescence are based on the ability of a substance to absorb light and emit light of a longer wavelength and therefore lower energy. The main difference is the time in which it takes to do so. In fluorescence, the emission is basically immediate and therefore generally only visible, if the light source is continuously on (such as UV lights); while phosphorescent material can store the absorbed light energy for some time and release light later, resulting in an afterglow that persists after the light has been switched off. Depending on the material, this afterglow can last anywhere from a few seconds to hours. So if it disappears immediately, it's fluorescence. If it lingers, it's phosphorescence. And if it needs activation, it's chemiluminescence. Simple!

consequential

Things that are consequential are important — extremely important. Electing a new president and having a baby are consequential. Killing a fly? Not so much.

Radiographic Testing (RT)

This method of weld testing makes use of X-rays, produced by an X-ray tube, or gamma rays, produced by a radioactive isotope. The basic principle of radiographic inspection of welds is the same as that for medical radiography.

Edible-nest Swiftlet (Aerodramus fuciphagus)

This nest is made exclusively out of the bird's saliva. It is built in layers, usually over protruding rocks on inclined walls of a dark sea cave. Swiftlets nest in colonies of thousands. Their nests are harvested to make a Chinese delicacy: bird's nest soup.

ultrasonic welding

Ultrasonic welding is an industrial technique whereby high-frequency ultrasonic acoustic vibrations are locally applied to workpieces being held together under pressure to create a solid-state weld. It is commonly used for plastics and metals, and especially for joining dissimilar materials. In ultrasonic welding, there are no connective bolts, nails, soldering materials, or adhesives necessary to bind the materials together. When applied to metals, a notable characteristic of this method is that the temperature stays well below the melting point of the involved materials thus preventing any unwanted properties which may arise from high temperature exposure of the materials.[1]

Battle of Stalingrad (1942-1943)

Unsuccessful German attack on the Russian city of Stalingrad during World War II from 1942 to 1943, that was the furthest extent of German advance into the Soviet Union. 1.5 million casualties; Germany's defeat marked turning point in the war. One of the bloodiest battles in the history of warfare. Five month long battle.

why do pop rocks pop?

When you eat Pop Rocks, the moisture and temperature in your mouth melts the candy. The subsequent popping sounds are a result of the high-pressure CO2 bubbles being released into atmospheric pressure!

specuation

When you guess about how something is going to come out (or how it happened), that's speculation. You're making an educated guess. When buying or selling securities and future value and expected return are highly uncertain

Multiculturalism

a condition in which ethnic groups exist separately and share equally in economic and political life multiple cultures can coexist in a shared space

soil exhaustion

a condition in which soil has lost nutrients and becomes nearly useless for farming

interrelation

a connection between two things that makes them affect each other the way in which each of two or more things is related to the other or others.

excrescence

a distinct outgrowth on a human or animal body or on a plant, especially one that is the result of disease or abnormality. something that bulges out or is protuberant or projects from its surroundings

insolvency

a financial state that occurs if liabilities are greater than assets Insolvency is when someone is completely out of money. A company's insolvency means that it isn't able to pay its workers and may have to go out of business.

special interest group

a group of people or an organization seeking or receiving special advantages, typically through political lobbying. an organization of people with some common interest who try to influence government decisions

installment loan

a loan repaid with interest in equal periodic payments

Oligopoly

a market dominated by a few large producers or suppliers

Titration

a measured amount of a solution of unknown concentration is added to a known volume of a second solution until the reaction between them is just complete

Price index

a number that compares prices in one year with some earlier base year A price index is a normalized average of price relatives for a given class of goods or services in a given region, during a given interval of time. It is a statistic designed to help to compare how these price relatives, taken as a whole, differ between time periods or geographical locations

indemnity

a payment for damage or loss insurance Indemnity is a contractual obligation of one party to compensate the loss incurred to the other party due to the acts of the indemnitor or any other party. The duty to indemnify is usually, but not always, coextensive with the contractual duty to "hold harmless" or "save harmless".

Eponym

a person after whom a discovery, invention, place, etc., is named or thought to be named.

groupthink

a tendency of in-group members to conform without critically testing, analyzing, and evaluating ideas, that results in a narrow view of an issue

leotard

a tight-fitting garment of stretchy material that covers the body from the shoulders to the thighs (and may have long sleeves or legs reaching down to the ankles)

posterity

all future generations of people "the victims' names are recorded for posterity"

angle iron

an L shaped iron, steel bar or structural steel member used to make a frame rigid.

charismatic leader

an enthusiastic, self-confident leader whose personality and actions influence people to behave in certain ways cult

Price-to-Rent Ratio

average home price divided by annual rent in a community The price-to-rent ratio is the ratio of home prices to annualized rent in a given location and is used as a benchmark for estimating whether it is cheaper to rent or own property. The price-to-rent ratio is used as an indicator for whether housing markets are fairly valued, or in a bubble. The dramatic increase in the ratio leading up to the 2008-2009 housing market crash was, with hindsight, a red flag for the housing bubble.

Ethnocentrism

belief in the superiority of one's own ethnic group or culture comes as a result of lack of exposure to nuance

contingent worker

employee hired on something other than a full-time basis to supplement an organization's permanent workforce a transient worker; they do not expect full time work; contract worker

net exports

exports minus imports

deference

humble submission and respect. "he addressed her with the deference due to age"

When you hear the words, "Indian," or "Native American," you probably think of tipis. But, as a matter of fact, most Indians did not live in tipis. Tipis were used mainly by Plains Indians, such as the Lipan Apache, Comanche and Kiowa, after the Spanish introduced horses into North America about 500 years ago.

iroquois longhouse

blind materialism

just buying stuff to buy stuff

Zoot suit

men's clothing of extreme cut typically consisting of a thigh-length jacket with wide padded shoulders and baggy, pleated pants with narrow cuffs

When I was sent of errands, I always took my book with me, and by going one part of my errand quickly, I found time to get a lesson before my return. I used also to carry bread with me, enough of which was always in the house, and to which I was always welcome; for I was much better off in this regard than many of the poor white children in our neighborhood. This bread I used to bestow upon the hungry little urchins, who, in return, would give me that more valuable bread of knowledge.

narrative of the life of frederick douglass

The US Bureau of Truth and Knowledge

nice\

dysfunctional

not operating normally or properly

tentacular

of or relating to or resembling tentacles

forgo

omit or decline to take (something pleasant or valuable); go without. "she wanted to forgo the dessert and leave while they could"

mass hysteria

outbreak of irrational behavior that is spread by social contagion intense, fearful, anxious reaction by many people

stereotype

oversimplified, exaggerated, or unfavorable generalization about a category of people

stagflation

persistent high inflation combined with high unemployment and stagnant demand in a country's economy. In economics, stagflation or recession-inflation is a situation in which the inflation rate is high, the economic growth rate slows, and unemployment remains steadily high. It presents a dilemma for economic policy, since actions intended to lower inflation may exacerbate unemployment.

temperance

restraint or moderation, especially in regards to alcohol or food abstinence from alcoholic drink.

sublimation

solid to gas The term sublimation refers to a physical change of state and is not used to describe the transformation of a solid to a gas in a chemical reaction. For example, the dissociation on heating of solid ammonium chloride into hydrogen chloride and ammonia is not sublimation but a chemical reaction. Similarly the combustion of candles, containing paraffin wax, to carbon dioxide and water vapor is not sublimation but a chemical reaction with oxygen.

corporate welfare

tax breaks, bailouts, direct payments, and grants that the government gives to corporations

felicity

the ability to find appropriate expression for one's thoughts. suitability; eloquence; appropriateness

aristocracy

the highest class in certain societies, especially those holding hereditary titles or offices. Group of the most wealthy and privileged A person who's "born to rule" belongs to the ruling class, or aristocracy, and is "noble" just by being in the family line — whether they have done anything noble or not. In an aristocracy, a princess who doesn't visit sick children or clear land mines is still a princess.

association-is-causation fallacy

the incorrect idea that if two variables are associated in time, one must necessarily cause the other

hidden curriculum

the informal and unofficial aspects of culture that children are taught in school norms, beliefs, and values that are programmed into you subconsciously

labor force participation rate

the percentage of the working-age population in the labor force a much better metric than unemployment

production

the process that transforms resources into goods and services creating something out of nothing

subjugate

to conquer by force, bring under complete control To subjugate is to repress someone, or to make them subservient to you.

ran the gamut

to cover a wide range to encompass an entire range of something Her emotions ran the gamut from joy to despair.

Aggregate Expenditure

total spending on final goods and services in an economy during a given period, usually a year Final good: Any good that is not used as an ingredient in another good and is sold for the first time to an end user.

customary

usual, expected, routine, traditional

Induction brazing

utilizes high-frequency induction currents as the source of heat and is therefore limited to the joining of electrically conductive materials Induction brazing is a process in which two or more materials are joined together by a filler metal that has a lower melting point than the base materials using induction heating. In induction heating, usually ferrous materials are heated rapidly from the electromagnetic field that is created by the alternating current from an induction coil. Eddy current heating is what allows electromagnetic induction to heat any electrically conductive material. (Resistance)

felicitous

well chosen or suited to the circumstances. well put; fitting; well expressed

opportunity cost

whatever must be given up to obtain some item e.g the opportunity cost of going to work is that you could be at home reading a book.

sagacity

wisdom; sound judgement

Idolatry

worship of idols extreme admiration, love, or reverence for something or someone. Idolatry is the worship of an idol or cult image, being a physical image, such as a statue, or a person in place of God. In Abrahamic religions, namely Judaism, Christianity and Islam, idolatry connotes the worship of something or someone other than God as if it were God.

Acetylene must be used in tips that are designed to be used with acetylene. If acetylene is used in tips designed for other fuel gases, then the tip may overheat, causing a backfire or even causing the tip to explode.

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When asking nuclear weapons designers about the ethical concerns of their research: "Are automobile designers responsible for deaths caused by drunk drivers?"

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why is helium found in natural gas?

Most of the helium that is removed from natural gas is thought to form from radioactive decay of uranium and thorium in granitoid rocks of Earth's continental crust. As a very light gas, it is buoyant and seeks to move upward as soon as it forms. (alpha particles)

Is plasma conductive?

Plasma is a state of matter in which an ionized gaseous substance becomes highly electrically conductive to the point that long-range electric and magnetic fields dominate the behaviour of the matter.

root pass vs cover pass

Root pass: the first weld bead in a multiple pass weld Cover pass: the last weld bead in a multiple pass weld

Shielded Metal Arc Welding (SMAW)

Shielded metal arc welding (SMAW), also known as manual metal arc welding (MMA or MMAW), flux shielded arc welding[1] or informally as stick welding, is a manual arc welding process that uses a consumable electrode covered with a flux to lay the weld. An electric current, in the form of either alternating current or direct current from a welding power supply, is used to form an electric arc between the electrode and the metals to be joined. The workpiece and the electrode melts forming a pool of molten metal (weld pool) that cools to form a joint. As the weld is laid, the flux coating of the electrode disintegrates, giving off vapors that serve as a shielding gas and providing a layer of slag, both of which protect the weld area from atmospheric contamination. Because of the versatility of the process and the simplicity of its equipment and operation, shielded metal arc welding is one of the world's first and most popular welding processes. It dominates other welding processes in the maintenance and repair industry, and though flux-cored arc welding is growing in popularity, SMAW continues to be used extensively in the construction of heavy steel structures and in industrial fabrication. The process is used primarily to weld iron and steels (including stainless steel) but aluminium, nickel and copper alloys can also be welded with this method.[2] To strike the electric arc, the electrode is brought into contact with the workpiece by a very light touch of the electrode to the base metal. The electrode is then pulled back slightly. This initiates the arc and thus the melting of the workpiece and the consumable electrode, and causes droplets of the electrode to be passed from the electrode to the weld pool. Striking an arc, which varies widely based upon electrode and workpiece composition, can be the hardest skill for beginners. The orientation of the electrode to workpiece is where most stumble, if the electrode is held at a perpendicular angle to the workpiece the tip will likely stick to the metal which will fuse the electrode to the workpiece which will cause it to heat up very rapidly. The tip of the electrode needs to be at a lower angle to the workpiece, which allows the weld pool to flow out of the arc. As the electrode melts, the flux covering disintegrates, giving off shielding gases that protect the weld area from oxygen and other atmospheric gases. In addition, the flux provides molten slag which covers the filler as it travels from electrode to the weld pool. Once part of the weld pool, the slag floats to the surface and protects the weld from contamination as it solidifies. Once hardened, it must be chipped away to reveal the finished weld. As welding progresses and the electrode melts, the welder must periodically stop welding to remove the remaining electrode stub and insert a new electrode into the electrode holder. This activity, combined with chipping away the slag, reduces the amount of time that the welder can spend laying the weld, making SMAW one of the least efficient welding processes. In general, the operator factor, or the percentage of operator's time spent laying weld, is approximately 25%. The actual welding technique utilized depends on the electrode, the composition of the workpiece, and the position of the joint being welded. The choice of electrode and welding position also determine the welding speed. Flat welds require the least operator skill, and can be done with electrodes that melt quickly but solidify slowly. This permits higher welding speeds. Sloped, vertical or upside-down welding requires more operator skill, and often necessitates the use of an electrode that solidifies quickly to prevent the molten metal from flowing out of the weld pool. However, this generally means that the electrode melts less quickly, thus increasing the time required to lay the weld. The most common quality problems associated with SMAW include weld spatter, porosity, poor fusion, shallow penetration, and cracking. Weld spatter, while not affecting the integrity of the weld, damages its appearance and increases cleaning costs. Secondary finishing services are often required due to the aesthetic appearance caused by the occurrence of molten splatter.[15] It can be caused by excessively high current, a long arc, or arc blow, a condition associated with direct current characterized by the electric arc being deflected away from the weld pool by magnetic forces. Arc blow can also cause porosity in the weld, as can joint contamination, high welding speed, and a long welding arc, especially when low-hydrogen electrodes are used. Porosity, often not visible without the use of advanced nondestructive testing methods, is a serious concern because it can potentially weaken the weld. Porosity is caused when the gaseous shield did not sufficiently shield the molten weld metal while the bead is laid or while it is cooling. What happens is that the weld bead is overexposed to and absorbs; nitrogen, oxygen, and hydrogen from the atmosphere. When a porous weld cools, the newly absorbed gaseous molecules are released and the welder is left with a porous weld bead. Another defect affecting the strength of the weld is poor fusion, though it is often easily visible. It is caused by low current, contaminated joint surfaces, or the use of an improper electrode. Shallow penetration, another detriment to weld strength, can be addressed by decreasing welding speed, increasing the current or using a smaller electrode. Any of these weld-strength-related defects can make the weld prone to cracking, but other factors are involved as well. High carbon, alloy or sulfur content in the base material can lead to cracking, especially if low-hydrogen electrodes and preheating are not employed. Furthermore, the workpieces should not be excessively restrained, as this introduces residual stresses into the weld and can cause cracking as the weld cools and contracts. Additionally, the brightness of the weld area can lead to a condition called arc eye, in which ultraviolet light causes inflammation of the cornea and can burn the retinas of the eyes. SMAW is often used to weld carbon steel, low and high alloy steel, stainless steel, cast iron, and ductile iron. While less popular for non-ferrous materials, it can be used on nickel and copper and their alloys and, in rare cases, on aluminium. The thickness of the material being welded is bounded on the low end primarily by the skill of the welder, but rarely does it drop below 1.5 mm (0.06 in). No upper bound exists: with proper joint preparation and use of multiple passes, materials of virtually unlimited thicknesses can be joined. Furthermore, depending on the electrode used and the skill of the welder, SMAW can be used in any position. The choice of electrode for SMAW depends on a number of factors, including the weld material, welding position and the desired weld properties. The electrode is coated in a metal mixture called flux, which gives off gases as it decomposes to prevent weld contamination, introduces deoxidizers to purify the weld, causes weld-protecting slag to form, improves the arc stability, and provides alloying elements to improve the weld quality.[25] Electrodes can be divided into three groups—those designed to melt quickly are called "fast-fill" electrodes, those designed to solidify quickly are called "fast-freeze" electrodes, and intermediate electrodes go by the name "fill-freeze" or "fast-follow" electrodes. Fast-fill electrodes are designed to melt quickly so that the welding speed can be maximized, while fast-freeze electrodes supply filler metal that solidifies quickly, making welding in a variety of positions possible by preventing the weld pool from shifting significantly before solidifying.[26] The composition of the electrode core is generally similar and sometimes identical to that of the base material. But even though a number of feasible options exist, a slight difference in alloy composition can strongly impact the properties of the resulting weld. This is especially true of alloy steels such as HSLA steels. Likewise, electrodes of compositions similar to those of the base materials are often used for welding nonferrous materials like aluminium and copper.[27] However, sometimes it is desirable to use electrodes with core materials significantly different from the base material. For example, stainless steel electrodes are sometimes used to weld two pieces of carbon steel, and are often utilized to weld stainless steel workpieces with carbon steel workpieces.[28] Electrode coatings can consist of a number of different compounds, including rutile, calcium fluoride, cellulose, and iron powder. Rutile electrodes, coated with 25%-45% TiO2, are characterized by ease of use and good appearance of the resulting weld. However, they create welds with high hydrogen content, encouraging embrittlement and cracking. Electrodes containing calcium fluoride (CaF2), sometimes known as basic or low-hydrogen electrodes, are hygroscopic and must be stored in dry conditions. They produce strong welds, but with a coarse and convex-shaped joint surface. Electrodes coated with cellulose, especially when combined with rutile, provide deep weld penetration, but because of their high moisture content, special procedures must be used to prevent excessive risk of cracking. Finally, iron powder is a common coating additive that increases the rate at which the electrode fills the weld joint, up to twice as fast.[29]

Lambda point

The Lambda point is the temperature at which normal fluid helium (helium I) makes the transition to superfluid helium II (approximately 2.17 K at 1 atmosphere).

Plasma torch

The basic plasma cutting process involves creating an electrical channel of superheated, electrically ionized gas i.e. plasma from the plasma cutter itself, through the work piece to be cut, thus forming a completed electric circuit back to the plasma cutter through a grounding clamp. This is accomplished by a compressed gas (oxygen, air, inert and others depending on material being cut) which is blown through a focused nozzle at high speed toward the work piece. An electrical arc is then formed within the gas, between an electrode near or integrated into the gas nozzle and the work piece itself. The electrical arc ionizes some of the gas, thereby creating an electrically conductive channel of plasma. As electricity from the cutter torch travels down this plasma it delivers sufficient heat to melt through the work piece. At the same time, much of the high velocity plasma and compressed gas blow the hot molten metal away, thereby separating, i.e. cutting through, the work piece. The arcs are generated in a three step process. A high voltage spark briefly ionizes the air within the torch head. This makes the air conductive and allows the "pilot arc" to form. The pilot arc forms within the torch head, with current flowing from the electrode to the nozzle inside the torch head. The pilot arc burns up the nozzle, a consumable part, while in this phase. The air then blows the plasma out the nozzle towards the work, providing a current path from the electrode to the work. When the control system senses current flowing from the electrode to the work, it cuts the electrical connection to the nozzle. Current then flows from the electrode to the work, and the arc forms outside the nozzle. Cutting can then proceed, without burning up the nozzle. Nozzle life is limited by the number of arc starts, not cutting time. Thermal plasmas are generated in plasma torches by direct current (DC), alternating current (AC), radio-frequency (RF) and other discharges. DC torches are the most commonly used and researched, because when compared to AC: "there is less flicker generation and noise, a more stable operation, better control, a minimum of two electrodes, lower electrode consumption, slightly lower refractory [heat] wear and lower power consumption". In a DC torch, the electric arc is formed between the electrodes (which can be made of copper, tungsten, graphite, molybdenum, silver etc.), and the thermal plasma is formed from the continual input of carrier/working gas, projecting outward as a plasma jet/flame (as can be seen in the adjacent image). In DC torches, the carrier gas can be, for example, either oxygen, nitrogen, argon, helium, air, or hydrogen;[5] and although termed such, it does not have to be a gas (thus, better termed a carrier fluid). For example, a research plasma torch at the Institute of Plasma Physics (IPP) in Prague, Czech Republic, functions with an H2O vortex (as well as a small addition of argon to ignite the arc), and produces a high temperature/velocity plasma flame.[6] In fact, early studies of arc stabilization employed a water-vortex.[7] Overall, the electrode materials and carrier fluids have to be specifically matched to avoid excessive electrode corrosion or oxidation (and contamination of materials to be treated), while maintaining ample power and function.

Brazing and soldering are both classified by the American Welding Society as liquid-solid phase bonding processes. Liquid means that the filler metal is melted; solid means that the base material or materials are not melted. The phase is the temperature at which bonding takes place between the solid base material and the liquid filler metal. The bond between the base material and filler metal is a metallurgical bond because no melting or alloying of the base metal occurs. If done correctly, this bond results in a joint having four- or five-times the tensile strength of that of the filler metal itself. How? Tensile strength of a joint is its ability to withstand being pulled apart, Figure 33-8. A brazed joint can be made that has a tensile strength four- to five-times higher than the filler metal itself. If a few drops of water are placed between two smooth and flat panes of glass and the panes are pressed together, then a tensile load is required to pull the panes of glass apart. The water, which has no tensile strength itself, has added tensile strength to the glass joint. The glass is being held together by the surface tension of the water. As the space between the pieces of glass decreases, the tensile strength increases. The same action takes place with a brazed or soldered joint. As the joint spacing decreases, the surface tension increases the tensile strength of the joint, Table 33-1. Shear strength of a joint is its ability to withstand a force parallel to the joint, Figure 33-9. For a solder or braze joint, the shear strength depends on the amount of overlapping area of the base parts. The greater the area that is overlapped, the greater is the strength. Ductility of a joint is its ability to bend without failing. Most brazing and soldering alloys are ductile metals, so the joint made with these alloys is also ductile. Fatigue resistance of a metal is its ability to be bent repeatedly without exceeding its elastic limit and without failure. For most soldered or brazed joints, fatigue resistance is usually fairly low. As a joint is bent, the less ductile base materials cause a shear force to be applied to the filler metal, Figure 33-10, resulting in joint failure. Fatigue failures may also occur as a result of vibration.

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Brazing and soldering fluxes will remove light surface oxides, promote wetting, and aid in capillary action. The use of fluxes does not eliminate the need for good joint cleaning. Fluxes will not remove oil, dirt, paint, glues, heavy oxide layers, or other surface contaminants. Soldering fluxes are chemical compounds such as muriatic acid (dilute hydrochloric acid), sal ammoniac (ammonium chloride), or rosin. Brazing fluxes are chemical compounds such as fluorides, chlorides, boric acids, and alkalies. These compounds react to dissolve, absorb, or mechanically break up thin surface oxides that are formed as the parts are being heated. They must be stable and remain active through the entire temperature range of the solder or braze filler metal. The chemicals in the flux react with the oxides as either acids or bases. Some fluxes that are heated to a liquid so the parts can be dipped into the liquid flux are salts. The reactivity of a flux is greatly affected by temperature. As the parts are heated to the brazing or soldering temperature, the flux becomes more active. Some fluxes are completely inactive at room temperature. Most fluxes have a temperature range within which they are most effective. Care should be taken to avoid overheating fluxes. If they become overheated or burned, then they will stop working as fluxes, and they become a contamination in the joint. If overheating has occurred, then the welder must stop and clean off the damaged flux before continuing.

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Copper-zinc alloys are the most popular brazing alloys. They are available as regular and low-fuming alloys. The zinc in this braze metal has a tendency to burn out if it is overheated. Overheating is indicated by a red glow on the molten pool, which gives off a white smoke. The white smoke is zinc oxide. If zinc oxide is breathed in, it can cause zinc poisoning. Using a low-fuming alloy will help eliminate this problem. Examples of low-fuming alloys are RCuZn-B and RCuZn-C.

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Hydrogen has the fastest burning velocity of any of the fuel gases at 36 ft/sec. Hydrogen is much lighter than air. Therefore, when it is released, it diffuses quickly, reducing the possibility of accidental combustion. If a large quantity of hydrogen is allowed to burn uncontrolled, the gas rises into the flame. This means it burns in an upward direction, away from people in an area. Most other gases burn in a downward direction, which can trap people in an area. The chance of large quantities of hydrogen exploding is limited. For example, when the hydrogen-filled airship, the Hindenburg, caught fire and burned in 1931, no explosion occurred, and most of the people on board the airship survived. The low flame temperature restricts the use of the oxyhydrogen flame to cutting, usually underwater, and to gas welding and brazing on low-temperature metals such as aluminum.

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In a fermentative dairy process, lactic acid bacteria (LAB) growth and metabolic activities are needed to assure a high-quality final product. These microorganisms produce lactic acid via lactose fermentation, which leads to a rapid decrease in pH. Cheese and fermented milk manufacture depends, largely, on this factor, which is also crucial for ensuring control of pathogenic and spoilage microorganisms.

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On all but short welds, the welding bead will need to be restarted after a welder stops to change electrodes. Because the metal cools as a welder changes electrodes and chips slag when restarting, the penetration and buildup may be adversely affected. The slag should always be chipped and the weld crater should be cleaned each time before restarting the weld. This is important to prevent slag inclusions at the start of the weld. For SMAW Welding.

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Silver and gold are both used in small quantities when joining metals that will be used under corrosive conditions, when high joint ductility is needed, or when low electrical resistance is important. Because of the everincreasing price and reduced availability of these precious metals, other filler metals should first be considered. In many cases, other alloys can be used with great success. When substituting a different filler metal for one that has been used successfully, the new metal and joint should first be extensively tested.

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The wall thickness for pipe is determined by its schedule, or pressure range. The larger the diameter of the pipe, the greater its area. As the area increases, so must the wall thickness for the wall to withstand the same pressure range. The thickness of the pipe and fitting is the same when they are welded together. Threaded pipe is weakened because the threads reduce the wall thickness of the pipe.

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Why backing strip is used in welding?

A backing (strip) is a piece of metal that is placed on the backside of a weld joint to prevent the molten metal from dripping through the open root (burn through). It helps to ensure that 100% of the base metal's thickness is fused by the weld (full penetration). The backing strip used in a closed root may remain as part of the weld, or it may be removed. Because leaving the backing strip on a weld may cause it to fail due to concentrations of stresses along the backing strip, removable backup tapes have been developed. Backup tapes are made of high-temperature ceramics, Figure 6-2, that can be used to control penetration and prevent burnthrough. The tape can be peeled off after the weld is completed. Most welds do not use backing strips.

Bipolar neuron

A bipolar neuron, or bipolar cell, is a type of neuron that has two extensions (one axon and one dendrite). Many bipolar cells are specialized sensory neurons for the transmission of sense. As such, they are part of the sensory pathways for smell, sight, taste, hearing, touch, balance and proprioception. The other shape classifications of neurons include unipolar, pseudounipolar and multipolar. During embryonic development, pseudounipolar neurons begin as bipolar in shape but become pseudounipolar as they mature.

Ciliopathy

A ciliopathy is any genetic disorder that affects the cellular cilia or the cilia anchoring structures, the basal bodies,[1] or ciliary function.[2] Primary cilia are important in guiding the process of development, so abnormal ciliary function while an embryo is developing can lead to a set of malformations that can occur regardless of the particular genetic problem. Although ciliopathies are usually considered to involve proteins that localize to motile and/or immotile (primary) cilia or centrosomes, it is possible for ciliopathies to be associated with unexpected proteins such as XPNPEP3, which localizes to mitochondria but is believed to affect ciliary function through proteolytic cleavage of ciliary proteins.[4]

safety release valve vs. safety disc

A safety release valve is made up of a small ball held tightly against a seat by a spring. The release valve will reseat itself after the excessive pressure has been released. A safety disc is a thin piece of metal held between two seals, Figure 7-22. When a safety disc bursts to release excessive pressure, all of the gas in the cylinder will be released. A safety disc does not reseal, so it must be replaced before the regulator can be used again.

Flashback arrestor

A spring-loaded valve installed on oxyacetylene torches as a safety device to prevent flame from entering the torch hoses. A flashback arrestor will do the job of a reverse flow valve, and it will also stop the flame of a flashback.

Thermoplastic

A thermoplastic, or thermosoftening plastic, is a plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling.[1][2]

weldment

A unit formed by welding together an assembly of pieces.

phage (bacteriophage)

A virus that infects/kills bacteria. Bacteriophages or "phages" are viruses that infect bacteria. They are now believed to represent the most abundant biological entities with an estimated range of 10^30 to 10^32 total phage particles on earth, assuming that they outnumber bacteria about 10-fold. These bacterial viruses are present in ecosystems where bacteria have been found, including man-made ecological niches such as food fermentation vats. The industry has been dealing with this biological phenomenon for many years now and has relied on a variety of practical approaches to control phages, which include adapted factory design, improved sanitation, adequate ventilation, process changes, improved starter medium, and culture rotation.3-5 Despite extensive efforts, however, phage infection of starter LAB cultures remains the most common cause of slow or incomplete fermentation in the dairy industry, and both researchers and industrial technologists are aware of regular, although unpublished, cases where phage infections actually cause product downgrading.

how is acetylene obtained?

Acetylene is produced by any of three methods: by reaction of water with calcium carbide (CaC2), by passage of a hydrocarbon through an electric arc, or by partial combustion of methane with air or oxygen. Acetylene is produced by mixing calcium carbide (CaC2) with water (H2O). Calcium carbide is produced by smelting coke (a coal by-product) and lime in air-tight electric arc furnaces. After smelting, the calcium carbide is cooled, crushed, and packed in dry, air-tight containers. Either a fixed or portable acetylene generator, Figure 31-49, is used to mix the calcium carbide with water. In the generator, crushed calcium carbide is dropped into a large tank of water. The carbon (C) in calcium carbide (CaC2) unites with the hydrogen (H) in water (H2O) to form two products. These two products are acetylene (C2H2), which bubbles out, and calcium hydroxide [Ca(OH)2], which drops to the bottom, Figure 31-50. The acetylene gas is drawn off and may be used immediately or pumped into storage cylinders for later use. One curious discovery of acetylene is on Enceladus, a moon of Saturn. Natural acetylene is believed to form from catalytic decomposition of long-chain hydrocarbons at temperatures of 1,700 K (1,430 °C; 2,600 °F) and above.

Activated alumina

Activated alumina is manufactured from aluminium hydroxide by dehydroxylating it in a way that produces a highly porous material; this material can have a surface area significantly over 200 m²/g. The compound is used as a desiccant (to keep things dry by absorbing water from the air) and as a filter of fluoride, arsenic and selenium in drinking water. It is made of aluminium oxide (alumina; Al2O3). It has a very high surface-area-to-weight ratio, due to the many "tunnel like" pores that it has. Used as a desiccant, it works by a process called adsorption. The water in the air actually sticks to the alumina itself in between the tiny passages as the air passes through them. The water molecules become trapped so that the air is dried out as it passes through the filter. This process is reversible. If the alumina desiccant is heated to ~200 °C, it will release the trapped water. This process is called regenerating the desiccant.

Agonist

An agonist is a chemical that binds to a receptor and activates the receptor to produce a biological response. Whereas an antagonist blocks the action of the agonist, and an inverse agonist causes an action opposite to that of the agonist. Receptors can be activated by either endogenous agonists (such as hormones and neurotransmitters) or exogenous agonists (such as drugs), resulting in a biological response. A physiological agonist is a substance that creates the same bodily responses but does not bind to the same receptor. An endogenous agonist for a particular receptor is a compound naturally produced by the body that binds to and activates that receptor. For example, the endogenous agonist for serotonin receptors is serotonin, and the endogenous agonist for dopamine receptors is dopamine.

Why do beekeepers spray smoke on bees?

Beekeepers use smokers before they have to inspect a hive or retrieve honey for extraction. When a beekeeper sprays smoke on bees, it does two things: it limits their sense of smell (also known as pheromones) and it initiates their survival response. Bees communicate through smell. They will release pheromones to communicate a message to one another. When an intruder is near the hive, bees will release an alarm pheromone that will cause the rest of the bees to react defensively. This alarm will make the other bees ready to stage an attack against the threat that is approaching them. A bee smoker masks the pheromone, leaving bees unaware of an alarm. Without their sense of smell, other bees won't know of any danger and therefore, they stay calm. A bee smoker simulates a forest fire for honeybees. As soon as bees come into contact with smoke, they go into survival mode. Because they think that their surroundings are on fire, the honeybees will begin preparations to leave their hive. They eat as much honey as they can so it can be saved from the flames and moved to their new home. This not only distracts bees from beekeepers, but full stomachs also make bees happy. When a bee has a belly full of honey, their abdomens expand so much that they can't bend over to sting a predator.

Chitin

Chitin, a long-chain polymer of N-acetylglucosamine, is a derivative of glucose. It is a primary component of cell walls in fungi, the exoskeletons of arthropods, such as crustaceans and insects, the radulae of molluscs, cephalopod beaks, and the scales of fish and lissamphibians.[1] The structure of chitin is comparable to another polysaccharide—cellulose, forming crystalline nanofibrils or whiskers. In terms of function, it may be compared to the protein keratin. Chitin has proved useful for several medicinal, industrial and biotechnological purposes.

DNA-barcoded microbial spores can trace origin of objects, agricultural products

Every year, an estimated 48 million Americans get sick from foodborne illnesses, resulting in some 128,000 hospitalizations and 3,000 deaths, according to the U.S. Centers for Disease Control and Prevention. This public health problem is compounded by billions in economic damage from product recalls, highlighting the need to rapidly and accurately determine the sources of foodborne illnesses. With the increasing complexity of global supply chains for the myriad foods available to consumers, however, the task of tracing the exact origin of contaminated items can be difficult. In a novel solution that can help determine the origin of agricultural products and other goods, Harvard Medical School scientists have developed a DNA-barcoded microbial system that can be used to label objects in an inexpensive, scalable and reliable manner. "Spores are in many ways an old-school solution and have been safely sprayed onto agricultural goods as soil inoculants or biological pesticides for decades. We just added a small DNA sequence we can amplify and detect," The research team created custom-made DNA sequences that they integrated into the genomes of the spores of two microorganisms—Saccharomyces cerevisiae, also known as baker's yeast, and Bacillus subtilis, a common and widespread bacterium that has numerous commercial uses, including as a dietary probiotic, a soil inoculant and a fermenting agent in certain foods. These spores can be cheaply grown in the lab in large numbers. The synthetic DNA sequences are short and do not code for any protein product, and are thus biologically inert. Inserted into the genome in tandem, the sequences are designed so that billions of unique barcodes can be created. The team also ensured that DNA-barcoded spores could not multiply, grow and spread in the wild. They did so by using microbial strains that require specific nutritional supplementation and by deleting genes required for the spores to germinate and grow. Experiments involving from hundreds of millions to more than a trillion of the modified spores confirmed that they are unable to form colonies. To read the DNA barcodes, the researchers used an inexpensive CRISPR-based tool that can detect the presence of a genetic target rapidly and with high sensitivity. The technology, called SHERLOCK, was developed at the Broad Institute of MIT and Harvard, in a collaboration led by institute members James Collins and Feng Zhang. "Spores can survive in the wild for an extremely long time and are a great medium for us to incorporate DNA barcodes into," said study co-first author Jason Qian, a graduate student in systems biology at HMS. "Identifying the barcodes is straightforward, using a plate reader and an orange plastic filter on a cell phone camera. We don't envision any challenges for field deployability."

SMAW Electrodes

F3 E6010 and E6011 Electrodes Both of these electrodes have cellulose-based fluxes. As a result, these electrodes have a forceful arc with little slag left on the weld bead. F2 E6012 and E6013 Electrodes These electrodes have rutile-based fluxes, giving a smooth, easy arc with a thick slag left on the weld bead. F4 E7016 and E7018 Electrodes Both of these electrodes have a mineral-based flux. The resulting arc is smooth and easy, with a very heavy slag left on the weld bead.

Flux-Cored Arc Welding (FCAW)

Flux-cored arc welding (FCAW or FCA) is a semi-automatic or automatic arc welding process. FCAW requires a continuously-fed consumable tubular electrode containing a flux and a constant-voltage or, less commonly, a constant-current welding power supply. An externally supplied shielding gas is sometimes used, but often the flux itself is relied upon to generate the necessary protection from the atmosphere, producing both gaseous protection and liquid slag protecting the weld. The process is widely used in construction because of its high welding speed and portability.

globular transfer

Globular transfer is generally used on thin materials and at a very low current range. In the globular transfer, the arc melts the end of the electrode, forming a molten ball of metal. When the ball of metal becomes so large, its surface tension cannot hold it onto the end of the wire. It falls across the arc most frequently landing in the molten weld pool. Because there is little control over where the glob of metal lands and the weld pool tends to be a small landing target, some globs fall outside of the molten weld pool becoming weld spatter. This process is rarely used by itself because of the large spatter caused by random globs falling outside of the weld. It is used more commonly in combination with pulsed-spray transfer. With this combination of processes, the molten weld pool is larger and the glob is more likely to land in the molten pool.

Gluten

Gluten (from Latin gluten, "to stick") is a group of proteins, called prolamins and glutelins,[1] which occur with starch in the endosperm of various cereal grains. This protein complex supplies 75-85% of the total protein in bread wheat.[2][3] It is found in related wheat species and hybrids, (such as spelt, khorasan, emmer, einkorn, and triticale), barley, rye, and oats,[4] as well as products derived from these grains, such as breads and malts. Glutens, especially Triticeae glutens, have unique viscoelastic and adhesive properties, which give dough its elasticity, helping it rise and keep its shape and often leaving the final product with a chewy texture.[2][5][6] These properties and its relative low cost are the reasons why gluten is so widely demanded by the food industry and for non-food uses.[6] Prolamins are, by convention, referred to with different names dependent on the grain from which they are sourced.[7] When found in wheat, prolamins are referred to as gliadins; in barley, they are referred to as hordeins; in rye, secalins; and in oats, avenins. These protein classes are collectively referred to as "gluten".[4] Similarly, glutelins found in wheat are typically called glutenins.[8] True gluten is limited to these four grains.[1] (The storage proteins in maize and rice are sometimes called glutens, but they differ from true gluten.[1])

HSLA Steel

High-strength low-alloy steel (HSLA) is a type of alloy steel that provides better mechanical properties or greater resistance to corrosion than carbon steel. HSLA steels vary from other steels in that they are not made to meet a specific chemical composition but rather specific mechanical properties. They have a carbon content between 0.05-0.25% to retain formability and weldability. Other alloying elements include up to 2.0% manganese and small quantities of copper, nickel, niobium, nitrogen, vanadium, chromium, molybdenum, titanium, calcium, rare earth elements, or zirconium.[1][2] Copper, titanium, vanadium, and niobium are added for strengthening purposes.[2] These elements are intended to alter the microstructure of carbon steels, which is usually a ferrite-pearlite aggregate, to produce a very fine dispersion of alloy carbides in an almost pure ferrite matrix. This eliminates the toughness-reducing effect of a pearlitic volume fraction yet maintains and increases the material's strength by refining the grain size, which in the case of ferrite increases yield strength by 50% for every halving of the mean grain diameter. Precipitation strengthening plays a minor role, too. Their yield strengths can be anywhere between 250-590 megapascals (36,000-86,000 psi). Because of their higher strength and toughness HSLA steels usually require 25 to 30% more power to form, as compared to carbon steels. Copper, silicon, nickel, chromium, and phosphorus are added to increase corrosion resistance. Zirconium, calcium, and rare earth elements are added for sulfide-inclusion shape control which increases formability. These are needed because most HSLA steels have directionally sensitive properties. Formability and impact strength can vary significantly when tested longitudinally and transversely to the grain. Bends that are parallel to the longitudinal grain are more likely to crack around the outer edge because it experiences tensile loads. This directional characteristic is substantially reduced in HSLA steels that have been treated for sulfide shape control.

Spore

In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, fungi and protozoa.[1] Bacterial spores are not part of a sexual cycle but are resistant structures used for survival under unfavourable conditions. Myxozoan spores release amoebulae into their hosts for parasitic infection, but also reproduce within the hosts through the pairing of two nuclei within the plasmodium, which develops from the amoebula.[2] Spores are usually haploid and unicellular and are produced by meiosis in the sporangium of a diploid sporophyte. Under favourable conditions the spore can develop into a new organism using mitotic division, producing a multicellular gametophyte, which eventually goes on to produce gametes. Two gametes fuse to form a zygote which develops into a new sporophyte. This cycle is known as alternation of generations. The spores of seed plants are produced internally, and the megaspores (formed within the ovules) and the microspores are involved in the formation of more complex structures that form the dispersal units, the seeds and pollen grains. In fungi, both asexual and sexual spores or sporangiospores of many fungal species are actively dispersed by forcible ejection from their reproductive structures. This ejection ensures exit of the spores from the reproductive structures as well as travelling through the air over long distances. Many fungi thereby possess specialized mechanical and physiological mechanisms as well as spore-surface structures, such as hydrophobins, for spore ejection. These mechanisms include, for example, forcible discharge of ascospores enabled by the structure of the ascus and accumulation of osmolytes in the fluids of the ascus that lead to explosive discharge of the ascospores into the air.

Metals react with water to produce

In general the reactions of metals with water produce hydrogen gas (H 2 ) and the hydroxides of the metals. Metals with moderate to low reactivity react very slowly with water. However, they react moderately with steam when heated and give hydrogen gas and metal oxides. Most alkali metals and alkaline earth metals react with water to produce hydrogen. The alkali metals comprise Group 1 of the periodic table, and include lithium, sodium, potassium, rubidium, cesium and francium. The alkaline earth metals comprise Group 2, and include beryllium, magnesium, calcium, strontium, barium and radium. Beryllium, however, does not react with water, and francium is much too rare and unstable to be relevant to this question. When mixed with water, the alkaline earth metals generally produce a weaker reaction than the alkali metals.

Flavor-changing neutral current

In theoretical physics, flavor-changing neutral currents or flavour-changing neutral currents (FCNCs) are hypothetical interactions that change the flavor of a fermion without altering its electric charge. FCNCs are generically predicted by theories that attempt to go beyond the Standard Model, such as the models of supersymmetry or technicolor. Their suppression is necessary for an agreement with observations, making FCNCs important in model-building.

Insect anatomy

Insects, like all arthropods, have no interior skeleton; instead, they have an exoskeleton, a hard outer layer made mostly of chitin which protects and supports the body. The insect body is divided into three parts: the head, thorax, and abdomen. The head is specialized for sensory input and food intake; the thorax, which is the anchor point for the legs and wings (if present), is specialized for locomotion; and the abdomen for digestion, respiration, excretion, and reproduction.[1]:22-48 Although the general function of the three body regions is the same across all insect species, there are major differences in basic structure, with wings, legs, antennae, and mouthparts being highly variable from group to group.[3]

Inverter SMAW machine

Inverter welding machines are much smaller than other types of machines of the same amperage range. This smaller size makes the welder much more portable as well as increases the energy efficiency, Figure 3-26. In a standard welding transformer, the iron core used to concentrate the magnetic field in the coils must be sized to work in harmony with the 60 cycle power. When the iron core is sized correctly, the magnetic field will build and collapse smoothly. An inverter welder uses solid-state electronic parts to change the incoming power from 60 cycles per second to several thousand cycles per second. This higher frequency allows the transformer to build and collapse the magnetic field much faster in a much lighter transformer. Inverter transformers may be as light as 7 lb (3 kg) and still do the work of a standard welding machine transformer weighing 100 lb (45 kg) or more. Additional electronic parts in the inverter welder remove the high frequency to turn the output into smooth DC welding power. The use of electronics in the inverter-type welder allows it to produce any desired type of welding power. Before the invention of this machine, each type of welding required a separate machine. Now, a single welding machine can produce the specific type of current needed for shielded metal arc welding, gas tungsten arc welding, gas metal arc welding, and plasma arc cutting. Because the machine can be light enough to be carried closer to work, shorter welding cables can be used. The welder does not have to walk as far to adjust the machine. In fact, some inverter welding machines allow the welder to make changes in the welding setting using a remote controller.

Lactic Acid Bacteria (LAB)

Lactic Acid Bacteria (LAB) are Gram-positive, non-sporeforming cocci, coccobacilli or rods with a DNA base composition of less than 53mol% G+C. They generally are non respiratory and lack catalase. They ferment glucose primarily to lactic acid, or to lactic acid, CO2 and ethanol. All LAB grow anaerobically, but unlike most anaerobes, they grow in the presence of O2 as "aerotolerant anaerobes". Although they lack catalase, they possess superoxide dismutase and have alternative means to detoxify peroxide radicals, generally through peroxidase enzymes. Lactic acid bacteria are among the most important groups of microorganisms used in food fermentations. They contribute to the taste and texture of fermented products and inhibit food spoilage bacteria by producing growth-inhibiting substances and large amounts of lactic acid. As agents of fermentation LAB are involved in making yogurt, cheese, cultured butter, sour cream, sausage, cucumber pickles, olives and sauerkraut, but some species may spoil beer, wine and processed meats. Because they obtain energy only from the metabolism of sugars, lactic acid bacteria are restricted to environments in which sugars are present. They have limited biosynthetic ability, having evolved in environments that are rich in amino acids, vitamins, purines and pyrimidines, so they must be cultivated in complex media that fulfill all their nutritional requirements. Most are free-living or live in beneficial or harmless associations with animals, although some are opportunistic pathogens. They are found in milk and milk products and in decaying plant materials. They are normal flora of humans in the oral cavity, the intestinal tract and the vagina, where they play a beneficial role.

Automatic plasma arc cutting (PAC) machines

Large, dedicated, computer-controlled cutting machines have been built specifically for PAC systems. These machines have the high travel speeds required to produce good-quality cuts and have a high volume of production. With these machines, the operator can input the specific cutting instructions such as speed, current, gas flow, location, and shape of the part to be cut, and the machine will make the cut with a high degree of accuracy once or any number of times. Robotic cutters are also available to perform high-quality, high-volume PAC. The advantage of using a robot is that, in most cases, the robot is capable of being set up for multitasking. When a robot is programmed, it can cut the part out, change and tool itself and weld the parts together, change the tool, and grind, drill, or paint the finished unit.

Moveable core SMAW

Movable coil or movable core machines are adjusted by turning a handwheel that moves the internal parts closer together or farther apart. The adjustment may also be made by moving a lever or turning a knob, Figure 3-23. These machines may have a high range and low range, but they do not have a fine adjusting knob. The closer the primary and secondary coils are, the greater the induced current; the greater the distance between the coils, the smaller the induced current, Figure 3-24. Moving the core in concentrates more of the magnetic force on the secondary coil, thus increasing the current. Moving the core out allows the field to disperse, and the current is reduced, Figure 3-25.

Nd:YAG laser

Nd:YAG (neodymium-doped yttrium aluminum garnet; Nd:Y3Al5O12) is a crystal that is used as a lasing medium for solid-state lasers. The dopant, triply ionized neodymium, Nd(III), typically replaces a small fraction (1%) of the yttrium ions in the host crystal structure of the yttrium aluminum garnet (YAG), since the two ions are of similar size.[1] It is the neodymium ion which provides the lasing activity in the crystal, in the same fashion as red chromium ion in ruby lasers.[1] good wiki

Project Azorian

One of the US Intel triumphs. We put a ship out in the ocean, and told everyone we were doing something else, but we were actually pulling a USSR submarine from the ocean floor to analyze it. The submarine split in two pieces when they hauled it off the ocean floor but the pieces the US did recover turned out to be very valuable information. Project Azorian (erroneously called "Jennifer" by the press after its Top Secret Security Compartment)[2] was a U.S. Central Intelligence Agency (CIA) project to recover the sunken Soviet submarine K-129 from the Pacific Ocean floor in 1974, using the purpose-built ship Hughes Glomar Explorer.[3][4] The 1968 sinking of K-129 occurred approximately 1,600 miles (2,600 km) northwest of Hawaii.[5] Project Azorian was one of the most complex, expensive, and secretive intelligence operations of the Cold War at a cost of about $800 million, or $4 billion today. The recovered section included two nuclear torpedoes, and thus Project Azorian was not a complete failure. The bodies of six crewmen were also recovered, and were given a memorial service and with military honors, buried at sea in a metal casket because of radioactivity concerns. Other crew members have reported that code books and other materials of apparent interest to CIA employees aboard the vessel were recovered, and images of inventory printouts exhibited in the documentary[9] suggest that various submarine components, such as hatch covers, instruments and sonar equipment were also recovered. White's documentary also states that the ship's bell from K-129 was recovered, and was subsequently returned to the Soviet Union as part of a diplomatic effort. The CIA considered that the project was one of the greatest intelligence coups of the Cold War.[10]

oxyfuel gas cutting (OFC)

Oxyfuel gas cutting (OFC) is a group of oxygen cutting processes that use heat from an oxyfuel gas flame to raise the temperature of the metal to its kindling temperature before a high-pressure stream of oxygen is directed onto the metal, causing it to be cut. The kindling temperature of a material is the temperature at which rapid oxidation (combustion) can begin. This cutting process is grouped and identified by the type of fuel gas used with oxygen to produce the preheat flame. Oxyfuel gas cutting is most commonly performed with oxyacetylene cutting (OFC-A). Manual, mechanized, and automatic OFC processes are used in industry. The outlet connection on a regulator is either a righthand fitting for oxygen or a left-hand fitting for fuel gases. the oxygen does the cutting, the fuel just heats the metal up

Plasma cutters have the unique ability to cut metals without making them very hot. This means that there is less distortion and heat damage than would be caused with an oxyacetylene cutting torch. Very intricate shapes can be cut out without warping.

Plasma can cut sheet metal so easily that it has become popular to use it to cut out the smallest of decorations. Most often the smallest silhouette of animals, people, buildings, and scenery used on gates, fences, barns, and so forth have been cut out using PAC.

Plastid

Plastids that contain chlorophyll can carry out photosynthesis and are called chloroplasts. Plastids can also store products like starch and can synthesize fatty acids and terpenes, which can be used for producing energy and as raw material for the synthesis of other molecules. For example, the components of the plant cuticle and its epicuticular wax are synthesized by the epidermal cells from palmitic acid, which is synthesized in the chloroplasts of the mesophyll tissue. All plastids are derived from proplastids, which are present in the meristematic regions of the plant. Proplastids and young chloroplasts commonly divide by binary fission, but more mature chloroplasts also have this capacity. Chloroplasts: green plastids for photosynthesis; see also etioplasts, the predecessors of chloroplasts Chromoplasts: coloured plastids for pigment synthesis and storage Gerontoplasts: control the dismantling of the photosynthetic apparatus during plant senescence Leucoplasts: colourless plastids for monoterpene synthesis; leucoplasts sometimes differentiate into more specialized plastids: Amyloplasts: for starch storage and detecting gravity (for geotropism) Elaioplasts: for storing fat Proteinoplasts: for storing and modifying protein Tannosomes: for synthesizing and producing tannins and polyphenols

Preheating and postheating welds

Preheating is the application of heat to the metal before it is welded. This process helps to reduce cracking, hardness, distortion, and stresses by reducing the thermal shock from the weld and slowing the cooldown rate. Preheating is most often required on large, thick plates, when the plate is very cold, on days when the temperature is very cold, when small diameter electrodes are used, on high-carbon or manganese steels, on complex shapes, or with fast welding speeds. Postheating is the application of heat to the metal after welding. Postheating is used to slow the cooling rate and reduce hardening.

Chrysanthemum

Pyrethrum (Chrysanthemum [or Tanacetum] cinerariaefolium) is economically important as a natural source of insecticide. The flowers are pulverized, and the active components, called pyrethrins, which occur in the achenes, are extracted and sold in the form of an oleoresin. This is applied as a suspension in water or oil, or as a powder. Pyrethrins attack the nervous systems of all insects, and inhibit female mosquitoes from biting. In sublethal doses, they have an insect-repellent effect. They are harmful to fish, but are far less toxic to mammals and birds than many synthetic insecticides. They are not persistent, being biodegradable, and also decompose easily on exposure to light. Pyrethroids such as permethrin are synthetic insecticides based on natural pyrethrum. Despite this, chrysanthemum leaves are still a major host for destructive pests, such as leafminer flies including L. trifolii.[14] The pyrethrins occur in the seed cases of the perennial plant pyrethrum (Chrysanthemum cinerariaefolium), which has long been grown commercially to supply the insecticide. Pyrethrins have been used as an insecticide for thousands of years. It is believed that the Chinese crushed chrysanthemum plants and used the powder as an insecticide as early as 1000 BC. It was widely known that the Chou Dynasty in China widely used pyrethrin for its insecticide properties.[8] For centuries, crushed Chrysanthemum flowers have been used in Iran to produce Persian Powder, an insecticide for household use. Pyrethrins were identified as the potent chemical in the Chrysanthemum plants responsible for the insecticidal properties in the crushed flowers around 1800 in Asia. In the Napoleonic Wars, French soldiers used the flowers to keep away fleas and body lice. Commercial pyrethrin production mainly takes place in mountainous equatorial zones. The commercial cultivation of the Dalmatian chrysanthemum takes place at an altitude of 3000 to 6000 meters above sea level.[13] This is done because pyrethrin concentration has been shown to increase as elevation increases to this level. Growing these plants does not require much water because semiarid conditions and a cool winter deliver optimal pyrethrin production. Most of the world's supply of pyrethrin and C. cinerariaefolium comes from Kenya, which produces the most potent flowers. It is a major source of export income for Kenya and source of over 3,500 additional jobs. About 23,000 tons were harvested in 1975. The active ingredients are extracted with organic solvents to give a concentrate containing the six types of pyrethrins: pyrethrin I, pyrethrin II, cinerin I, cinerin II, jasmolin I, and jasmolin II.

quark-gluon plasma (QGP)

Quark-gluon plasma is a state of matter in which the elementary particles that make up the hadrons of baryonic matter are freed of their strong attraction for one another under extremely high energy densities. These particles are the quarks and gluons that compose baryonic matter.[22] In normal matter quarks are confined; in the QGP quarks are deconfined. In classical QCD quarks are the fermionic components of hadrons (mesons and baryons) while the gluons are considered the bosonic components of such particles. The gluons are the force carriers, or bosons, of the QCD color force, while the quarks by themselves are their fermionic matter counterparts. Quark-gluon plasma or QGP is an interacting localized assembly of quarks and gluons at thermal (local kinetic) and (close to) chemical (abundance) equilibrium. The word plasma signals that free color charges are allowed. Quark-gluon plasma filled the entire Universe before matter was created.

Rote learning

Rote learning is a memorization technique based on repetition. The idea is that one will be able to quickly recall the meaning of the material the more one repeats it. Some of the alternatives to rote learning include meaningful learning, associative learning, and active learning. Learning information in a relatively uninterpreted form, without making sense of it or attaching much meaning to it.

sizing aluminum wire vs copper

Since aluminum is a worse conductor than copper, aluminum wires should be sized one size larger than their copper amperage equivalent.

Why cut under water with Plasma?

So what's the reason for cutting under water?" And we're not talking about just cutting on a table that has water below the plate. Under water CNC plasma cutting actually submerges the plate below 2 to 4" of water, so the torch tip and the entire arc are submerged, just like we were doing at IMTS. The first thing you notice when cutting under water is that it dramatically reduces the noise emitted by the plasma arc. Noise levels from dry plasma cutting can be as high as 120 decibels, requiring hearing protection for the operator and anyone else working near the machine. By submerging the plate, the noise level can be reduced by as much as 40 dB, and for most cutting will be well below the 85 dB level allowable for continuous exposure. In a small shop this can affect the working environment in the entire building, and make for a much nicer working environment. Next, you will notice that under water plasma cutting significantly reduces the brightness of the arc. When cutting on a dry table, the arc is so bright that anyone in the area should be wearing dark safety glasses of an appropriate shade, or a welding helmet. Looking at the plasma arc, either directly or at an angle, can cause serious eye damage. But when that same arc is under a few inches of water, all you see is a bubbling reddish-purple glow. Operators should still wear eye protection, but dark shades are no longer needed, making the entire working area safer and more pleasant. When plasma cutting under water, the water will absorb the vast majority of the plasma smoke. Instead of billowing clouds of smoke that have to be captured by an expensive dust collector, a water table will usually emit an occasion little puff that quickly dissipates. Cutting under water keeps the entire plate cooler, which reduces warping of the cut parts and the skeleton, or scrap plate. Heat distortion occurs when you heat up one part of a plate and then let it cool, causing uneven expansion and contraction. Most people want their cut parts to remain flat, and when the scrap curls up, it can cause problems by interfering with the machine. The cooling effect of the water also means that you can immediately handle the parts after cutting. When cutting on a dry table, the parts can remain hot for hours, making them more difficult to handle, and also posing a safety risk. There are trade-offs with every decision. Water tables are not the perfect solution, or else everyone would be using them. Here are some things to consider about a water table that might put you off a little. Cleaning - water tables will accumulate slag and sludge at the bottom of the table, and require periodic clean out. So do dry tables, but it's a little messier with a water table. A "tilt-frame" table from JB Technical Services is more easily cleaned by lifting out the slag buckets. But after a number of years of operation, even those tables will need to be completely emptied and thoroughly cleaned out in order to maintain proper operation. Water Disposal - if you do empty the water table, you might have a "toxic waste" on your hands. Depending on what you cut and where you are located, you might have to pay someone to pump out the table and haul away the waste water and sludge. Shop Mess - pulling wet cut parts out of a table all day is going to spill some dirty water on your floor. White carpeting is not recommended! Dirty Parts - The fine particles suspended in the water will settle on top of the plate while cutting. Most shops with a water table also install a hose for the operator to use to spray off the parts after he lowers the water.

Brazing vs soldering

The American Welding Society (AWS) defines brazing as such a process which involves a filler metal which has a liquidus above 450°C (842°F). Soldering, on the other hand, involves filler metals with a liquidus of 450°C or below. Brazing occurs at a temperature above 840°F (450°C), and the parts being joined must be fitted so that the joint spacing is very small, approximately 0.025 in. (0.6 mm) to 0.002 in. (0.06 mm). This small spacing allows capillary action to draw the filler metal into the joint when the parts reach the proper phase temperature. Capillary action is the force that pulls water up into a paper towel or pulls a liquid into a very fine straw. Capillary action occurs because of intermolecular forces between the liquid and surrounding solid surfaces. If the diameter of the tube is sufficiently small, then the combination of surface tension (which is caused by cohesion within the liquid) and adhesive forces between the liquid and container wall act to propel the liquid.

Hagedorn temperature

The Hagedorn temperature, TH, is the temperature in theoretical physics where hadronic matter (i.e. ordinary matter) is no longer stable, and must either "evaporate" or convert into quark matter; as such, it can be thought of as the "boiling point" of hadronic matter. The Hagedorn temperature exists because the amount of energy available is high enough that matter particle (quark-antiquark) pairs can be spontaneously pulled from vacuum. Thus, naively considered, a system at Hagedorn temperature can accommodate as much energy as one can put in, because the formed quarks provide new degrees of freedom, and thus the Hagedorn temperature would be an impassable absolute hot. However, if this phase is viewed as quarks instead, it becomes apparent that the matter has transformed into quark matter, which can be further heated. In string theory, it indicates a phase transition: the transition at which very long strings are copiously produced. It is controlled by the size of the string tension, which is smaller than the Planck scale by the some power of the coupling constant. By adjusting the tension to be small compared to the Planck scale, the Hagedorn transition can be much less than the Planck temperature. Traditional grand unified string models place this in the magnitude of 10^30 kelvin, two orders of magnitude smaller than the Planck temperature. Such temperatures have not been reached in any experiment and are far beyond the reach of current, or even foreseeable technology.

Tetris effect

The Tetris effect (also known as Tetris syndrome) occurs when people devote so much time and attention to an activity that it begins to pattern their thoughts, mental images, and dreams.[1] It takes its name from the video game Tetris. People who have played Tetris for a prolonged amount of time can find themselves thinking about ways different shapes in the real world can fit together, such as the boxes on a supermarket shelf or the buildings on a street.[1] They may see coloured images of pieces falling into place on an invisible layout at the edges of their visual fields or when they close their eyes.[1] They may see such coloured, moving images when they are falling asleep, a form of hypnagogic imagery. Me with GFX.

Homolysis

The cleavage of a covalent bond that each fragment departs with one of the electrons of the covalent bond that joined them; these fragments are referred to as "radicals" Homolytic fission is chemical bond dissociation of a molecule by a process where each of the fragments retains one of the originally bonded electrons. During homolytic fission of a neutral molecule with an even number of electrons, two free radicals will be generated.[1] That is, the two electrons involved in the original bond are distributed between the two fragment species. The energy involved in this process is called bond dissociation energy. Bond cleavage is also possible by a process called heterolysis. Triggered by UV or heat

Water cooled plasma torches

The cool water has to divert so there is equal heat transfer through the torch. Hafnium (Hf) is a ductile metal with good electrical properties and can be used by itself as a tip for the plasma electrodes. Hafnium's major benefit to plasma electrodes is its resistance to oxidation at elevated temperatures, so air can be used as the plasma gas. On hafnium/ tungsten, once the hafnium coating becomes damaged the cut quality will quickly deteriorate.

Arc blow

The deflection of a welding arc from its normal path because of uneven magnetic forces. When electrons flow, they create lines of magnetic force that circle around the path of flow, Figure 3-12. These lines of magnetic force are referred to as magnetic flux lines. They space themselves evenly along a current carrying wire. If the wire is bent, then the flux lines on one side are compressed together, and those on the other side are stretched out, Figure 3-13. The unevenly spaced flux lines try to straighten the wire so that the lines can be evenly spaced once again. The force that they place on the wire is usually small, so the wire does not move. However, when welding with very high amperages, 600 amperes or more, the force may actually cause the wire to move. The welding current flowing through a plate or any residual magnetic fields in the plate will result in unevenly spaced magnetic flux lines. These uneven flux lines can, in turn, cause the arc between the electrode and the work to move during welding. The term arc blow refers to this movement of the arc. Arc blow makes the arc drift like a string would drift in the wind. Arc blow can be more of a problem when the magnetic fields are the most uneven, such as when they are concentrated in corners, at the ends of plates, and when the work lead is connected to only one side of a plate, Figure 3-14 The more complex a weldment becomes, the more likely arc blow will become a problem. Complex weldments can distort the magnetic lines of flux in unexpected ways. If you encounter severe arc blow during a weld, stop welding and take corrective measures to control or reduce the arc blow. Arc blow can be controlled or reduced by connecting the work lead to the end of the weld joint, and then welding away from the work lead, Figure 3-15. Another way of controlling arc blow is to use two work leads, one on each side of the weld. The best way to eliminate arc blow is to use alternating current. Because alternating current changes directions, the flux lines do not become strong enough to bend the arc before the current changes direction. If it is impossible to move the work connection or to change to AC, a very short arc length can help control arc blow. A large tack weld or a change in the electrode angle can also help control arc blow.

torch standoff distance

The distance from the nozzle tip to the work. It is very critical to the quality of the plasma cuts.

Halogenation

The facility of halogenation is influenced by the halogen. Fluorine and chlorine are more electrophilic and are more aggressive halogenating agents. Bromine is a weaker halogenating agent than both fluorine and chlorine, while iodine is the least reactive of them all. The facility of dehydrohalogenation follows the reverse trend: iodine is most easily removed from organic compounds, and organofluorine compounds are highly stable. Fluorination Organic compounds, saturated and unsaturated alike, react readily, usually explosively, with fluorine. Fluorination with elemental fluorine (F2) requires highly specialised conditions and apparatus. Many commercially important organic compounds are fluorinated electrochemically using hydrogen fluoride as the source of fluorine. The method is called electrochemical fluorination. Aside from F2 and its electrochemically generated equivalent, a variety of fluorinating reagents are known such as xenon difluoride and cobalt(III) fluoride. Chlorination Chlorination is generally highly exothermic. Both saturated and unsaturated compounds react directly with chlorine, the former usually requiring UV light to initiate homolysis of chlorine. Chlorination is conducted on a large scale industrially; major processes include routes to 1,2-dichloroethane (a precursor to PVC), as well as various chlorinated ethanes, as solvents. Bromination Bromination is more selective than chlorination because the reaction is less exothermic. Most commonly bromination is conducted by the addition of Br2 to alkenes. An example of bromination is the organic synthesis of the anesthetic halothane from trichloroethylene:[5] Organobromine compounds are the most common organohalides in nature. Their formation is catalyzed by the enzyme bromoperoxidase which utilizes bromide in combination with oxygen as an oxidant. The oceans are estimated to release 1-2 million tons of bromoform and 56,000 tons of bromomethane annually.[6] Iodination Iodine is the least reactive halogen and is reluctant to react with most organic compounds. The addition of iodine to alkenes is the basis of the analytical method called the iodine number, a measure of the degree of unsaturation for fats. The iodoform reaction involves degradation of methyl ketones.

How to prepare thicker metal for welding

The groove may be ground, flame cut, plasma cut, gouged, or machined on the edge of the plate before or after the assembly. Bevels and V-grooves are best if they are cut before the parts are assembled. J-grooves and U-grooves can be cut either before or after assembly, Figure 6-26. The lap joint is seldom prepared with a groove because little or no strength can be gained by grooving this joint. The only advantage to grooving the lap joint design is to give additional clearance.

what happens in oven cleaning mode?

The oven is cleaned by heat, at temperatures above normal cooking temperatures. During the cleaning cycle the oven is heated to about 880 degrees Fahrenheit (471° C.). At this temperature, food soils inside the oven decompose, leaving behind a small amount of ash.

Pyrethrin

The pyrethrins are a class of organic compounds normally derived from Chrysanthemum cinerariifolium that have potent insecticidal activity by targeting the nervous systems of insects. Pyrethrin naturally occurs in chrysanthemum flowers and is often considered an organic insecticide when it is not combined with piperonyl butoxide or other synthetic adjuvants.[1] Their insecticidal and insect-repellent properties have been known and used for thousands of years. Pyrethrins delay the closure of voltage-gated sodium channels in the nerve cells of insects, resulting in repeated and extended nerve firings. This hyperexcitation causes the death of the insect due to loss of motor coordination and paralysis.[17] Resistance to pyrethrin has been bypassed by pairing the insecticide with synthetic synergists such as piperonyl butoxide. Together, these two compounds prevent detoxification in the insect, ensuring insect death.[18] Synergists make pyrethrin more effective, allowing lower doses to be effective. Pyrethrins are effective insecticides because they selectively target insects rather than mammals due to higher insect nerve sensitivity, smaller insect body size, lower mammalian skin absorption, and more efficient mammalian hepatic metabolism. Pyrethrins are gradually replacing organophosphates and organochlorides as the pesticides of choice as the latter compounds have been shown to have significant and persistent toxic effects to humans. Because they are biodegradable pyrethrins are widely preferred to pyrethroids, which are synthetic analogues of pyrethrin that accumulate in the environment.

Types of Welding Currents

The three different types of current used for welding are alternating current (AC), direct-current electrode negative (DCEN), and direct-current electrode positive (DCEP). The terms DCEN and DCEP have replaced the former terms direct-current straight polarity (DCSP) and direct-current reverse polarity (DCRP). DCEN and DCSP are the same currents, and DCEP and DCRP are the same currents. Some electrodes can be used with only one type of current. Others can be used with two or more types of current. Each welding current has a different effect on the weld. DCEN: In direct-current electrode negative, the electrode is negative and the work is positive, Figure 3-6. The electrons are leaving the electrode and traveling across the arc to the surface of the metal being welded. This results in approximately one-third of the welding heat on the electrode and two-thirds on the metal being welded. DCEN welding current produces a high electrode melting rate. DCEP: In direct-current electrode positive, the electrode is positive and the work is negative, Figure 3-7. The electrons are leaving the surface of the metal being welded and traveling across the arc to the electrode. This results in approximately two-thirds of the welding heat on the electrode and one-third on the metal being welded.

What is the key focus to any type of welding?

Weld pool manipulation. If you move in a circular motion at a 90 degree angle the weld will penetrate deep into the metal and the bead will be laid smoothly. You can also weld at different angles and use different weave patterns to achieve alternative penetration depths and bead patterns. These techniques will all result in varying levels of strength for the final weld.

Slag (welding)

Welding slag is a form of slag, or vitreous material produced as a byproduct of some arc welding processes, most specifically shielded metal arc welding (also known as stick welding), submerged arc welding, and flux-cored arc welding. Slag is formed when flux, the solid shielding material used in the welding process, melts in or on top of the weld zone. Slag is the solidified remaining flux after the weld area cools.[1] Welding flux is a combination of carbonate and silicate materials used in welding processes to shield the weld from atmospheric gases. When the heat of the weld zone reaches the flux, the flux melts and outgasses. The gases produced push the atmospheric gas back, preventing oxidation (and reactions with nitrogen). The melted flux covers the molten metal in the weld zone. Flux materials are chosen so that the density of the melted flux / slag is lower than that of the metal being welded, so that the flux floats to the top of the weld puddle and leaves pure or nearly pure metal to solidify below. Flux materials may also contribute to metal behavior in the molten metal, with physical or chemical alterations to the molten metal. The flux cover also helps thermally insulate the weld and reduce the cooling rate. Four welding processes use flux in slag-producing manners: - Shielded metal arc welding, also known as SMAW - Flux-core arc welding, also known as FCAW or FC - Submerged arc welding - Electroslag welding Removal of slag Slag does not contribute to strength or protection of metals after the welding process; it is waste material. Removal of the slag is necessary for four reasons: - ability to inspect the quality of the weld area; - aesthetics, or visual appearance; - if a second layer or pass of welding is to be made on top of the first; - to clean and clear the surface for coatings such as paint or oil. Removal is usually done using manual or power tools. Manual tools may include a welding or chipping hammer, which has a pointed tip on one end to break up large chunks of slag efficiently, or wire brushes. Power tools include angle grinders with grinder disks or wire brush wheels.

Why does wasp insecticide instantly kill wasps?

What you are describing is called knockdown. Insecticide strength can be measured by how fast they induce knockdown. Lots of factors go into this, from the size of the spray droplets to what it is mixed with. For wasp spray, speed is critical, as you'll want the wasps down before they can sting you! Knockdown insecticides are neurotoxins. Pyrethroids and pyrethrins, the active ingredient of most wasp sprays, cause knockdown quickly by affecting the sodium channels of insect nerves, holding them open. The nerves cannot reset, so the insect is immediately paralyzed and falls down. Carbamate and organophosphate insecticides work by blocking the enzyme acetylcholinesterase. Without this enzyme, nerve transmissions can't stop, causing the insect to have a full body seizure and fall to the ground. Pyrethroids are harmless to humans, but lethal to fish. Carbamates do affect humans, but they eventually wear off and some even have medicinal uses. Organophosphates are permanent: while some are safe for humans (like Malathion), others are very toxic and require antidotes in case of poisoning. Always read and follow the directions on your can of spray!

Flashback vs Backfire

When a flashback occurs, the flame is burning back inside the tip, torch, hose, or regulator. A flashback produces a high-pitched whistle. If the torch does flash back, close the oxygen valve at once and then close the fuel valve. The order in which the valves are closed is not as important as the speed at which they are closed. A flashback that reaches the cylinder may cause a fire or an explosion. A backfire occurs when a flame goes out with a loud snap or pop. A backfire may be caused by one or more of the following: ● Touching the tip against the workpiece ● Overheating the tip ● Operating the torch when the flame settings are too low ● Loose tip ● Damaged seats ● Dirt in the tip The problem that caused the backfire must be corrected before relighting the torch. A backfire may cause a flashback. Image: The purpose of the reverse flow valve is to prevent gases from accidentally flowing through the torch and into the wrong hose. If the gases being used are allowed to mix in the hose or regulator, they might explode. The reverse flow valve is a spring-loaded check valve that closes when gas tries to flow backward through the torch valves,

iguazu falls

a large waterfall on the border between Argentina and Brazil

vitreous

like glass in appearance or physical properties. vitreous humor: the transparent gelatinous tissue filling the eyeball behind the lens.

serial monogamist

someone who constantly has a significant other

Heat affected zone

the portion of the base metal whose mechanical properties or microstructure has been altered by the heat of welding, brazing, soldering,or thermal cutting

Laparoscopy

visual examination of the abdomen a surgical procedure in which a fiber-optic instrument is inserted through the abdominal wall to view the organs in the abdomen or to permit a surgical procedure.