تست - AYOOBZADEH

␣. See alpha. aberration, spherical. The aberration by

which light passing through the edge of a lens with

spherical surfaces comes to focus in a different im-

A. Abbreviation for absolute temperature.

age plane from that passing through the lens center.

. Abbreviation for A

ngstrom.

abherent. Any substance that prevents adhesion

of a material to itself or to another material. It may be

a. Abbreviation for atto-, a prefix meaning 10

−18

in the form of a dry powder (a silicate such as talc,

unit.

mica, or diatomaceous earth); a suspension (benton-

ite-water); a solution (soap-water); or a soft solid

AAAS. See American Association for the Ad-

(stearic acid, tallow waxes). Abherents are used as

vancement of Science.

dusting agents and mold washes in the adhesives,

rubber, and plastics industries. Fats and oils are used

AATCC. See American Associates of Textile

as abherents in the baking industry. Fluorocarbon

Chemists and Colorists.

resin coatings on metals are widely used on cooking

utensils.

abaca. (Manila hemp). The strongest vegetable

See antiblock agent; dusting agent.

fiber, obtained from the leaves of a tree of the banana

family. The fibers are 4–8 feet long, light in weight,

Abies Siberica oil. See fir needle oil.

soft, lustrous, and nearly white; they do not swell or

lose strength when wet. Denier ranges from 300 to

abietic acid. (abietinic acid; sylvic acid).

500. Combustible, but self-extinguishing.

CAS: 514-10-3. C

COOH (having a phenan-

Source: Philippines, Central America, Sumatra.

threne ring system). A major active ingredient of

Use: Heavy cordage and twine, especially for marine

rosin, where it occurs with other resin acids. The

use; manila paper.

term is often applied to these mixtures, separation of

See hemp.

which is not achieved in technical grade material.

Properties: Yellowish, resinous powder. Mp

abate. (O,O-dimethyl phosphorothioate-O,O-

172–175C, optical rotation −106. Soluble in alco-

diester with 4,4

′

-thiodiphenol; temephos).

hol, ether, chloroform, and benzene; insoluble in

CAS: 3383-96-8. [(CH

PSOC

]S.

water. Combustible.

Properties: Colorless crystals. Mp 30C.

Derivation: Rosin, pine resin, tall oil.

Hazard: Toxic by ingestion and inhalation. Cholin-

Method of purification: Crystallization.

esterase inhibitor. TLV: 10 mg/m

Grade: Technical.

Use: Pesticide.

Use: Abietates (resinates) of heavy metals as varnish

driers, esters in lacquers and varnishes, fermentation

Abbe´ condenser. Substage two-lens condenser

industries, soaps.

giving numerical aperture of 1:20–1:25. Three-lens

versions give numerical aperture of 1:40.

“Abitol” [Aqualon]. TM for a colorless, tacky,

very viscous liquid; mixture of tetra-, di-, and dehy-

Abbe´ number. (1) The reciprocal of dispersive

droabietyl alcohols made from rosin.

power. (2) The measure of optical dispersion of a

Use: Plasticizers, tackifiers, adhesive modifiers.

glass; the measure of two planes not displacing the

axis.

ablation experiment. An experiment designed

to produce an animal deficient in one or a few cell

Abegg’s rule. The solubility of salts of alkali

types in order to study cell lineage or cell function.

metals decreases in strong acids and increases in

The idea is to make a transgenic mouse with a toxin

weak acids as atomic weight increases. This is an

gene (often a diphtheria toxin) under control of a

empirical rule; sodium chloride is an exception.

specialized promoter which activates only in the

target cell type. When embryo development pro-

Abel-Pensky flash-point apparatus. In-

gresses to the point where it starts to form the target

strument used for the determination of the flash

tissue, the toxin gene is activated, and the target

point of petroleum.

tissue dies. Other tissues are unaffected.

aberration. Deviation from the ideal in an opti- ablative material. Any material that possesses

cal system, the image points being imperfect or a capability for rapidly dissipating heat from a sub-

improperly located. strate. Specialized ceramic tiles developed since

2ABRAM’S LAW

1980 for protection of the space shuttle have proved ing material to the aluminum, with application of

successful. The materials used are of two major heat and pressure.

types: (1) Fibers made from white silica, fused in an

oven, cut into blocks, and coated with borosilicate

abrasive, coated. See abrasive (2).

glass; these are extremely efficient at temperatures

up to 2300F. (2) An all-carbon composite (called

ABS. Abbreviation for (1) alkyl benzene sulfo-

reinforced carbon-carbon) made by laminating and

nate (detergent); (2) acrylonitrile-butadiene-styrene

curing layers of graphite fiber previously coated

copolymer.

with a resin, which is pyrolized to carbon. The re-

See ABS resin.

sulting tile is then treated with a mixture of alumina,

silicon, and silicon carbide. Such composites are

abscisic acid.

used for maximum-temperature (nose-cone) expo-

CAS: 21293-29-8. C

. A plant growth regula-

sure up to 3000F. Both types are undamaged by the

tor that promotes detachment of leaves and fruit.

heat and are reusable. The tiles are adhered to the

Properties: Colorless crystals. Mp 160C. Sublimes

body of the spacecraft with a silicone adhesive.

at 120C. Soluble in acetone, ether, chloroform;

Ablative materials used on early spaceship trials

slightly soluble in water. Optically active.

were fluorocarbon polymers and glass-reinforced

Occurrence: In plants, fruits, and vegetables from

plastics, but these were wholly or partially decom-

which it can be extracted. Also made synthetically.

posed during reentry.

Use: In orchard sprays to facilitate fruit harvesting,

defoliant, growth inhibitor.

Abram’s law. The strength of concrete depends

on the water/cement ratio.

absinthium. (wormwood). C

. An essen-

tial oil with intensely bitter taste due to presence of

abrasion. Gradual erosion of the surface of a

absinthin.

material both by physical forces (simultaneous cut-

Hazard: Toxic by ingestion.

ting, shearing, and tearing) and by chemical degra-

Use: A flavoring in liqueurs, vermouth.

dation, chiefly oxidation. Temperature is a signifi-

cant factor: friction may raise the temperature of the

surface layers to the point where they become sub-

absolute. (1) Free from admixture of other sub-

ject to chemical attack. Abrasion causes deteriora-

stances; pure. Example: absolute alcohol is dehy-

tion of many materials, especially of rubber (tire

drated ethanol, 99% pure. (2) The pure essential oil

treads), where it can be offset by a high percentage

obtained by double solvent extraction of flowers in

of carbon black; other materials subjected to abra-

the manufacture of perfumes.

sion in their service life are textiles (laundering),

See concrete (2). (3) absolute temperature.

leather and plastics (shoe soles, belting), and house

paints and automobile lacquers (airborne dust, grit,

absolute configuration. The configuration of

etc.).

four different substituent groups around an asym-

See abrasive.

metric carbon atom. The absolute configurations of

molecules in biochemistry are compared to the con-

abrasive. A finely divided, hard, refractory mate-

figuration of d- and l-glyceraldehyde.

rial, ranging from 6 to 10 on the Mohs scale, used to

reduce, smooth, clean, or polish the surfaces of oth-

absolute error. The actual difference between

er, less hard substances, such as glass, plastic, stone,

the approximate and the exact value in any calcula-

wood, etc. Natural abrasive materials include dia-

tion.

mond dust, garnet, sand (silica), corundum (alumi-

num oxide, emery), pumice, rouge (iron oxide), and

absolute temperature. The fundamental tem-

feldspar; the more important synthetic types are

perature scale used in theoretical physics and chem-

silicon carbide, boron carbide, cerium oxide, and

istry, and in certain engineering calculations, such as

fused alumina. Abrasive in powder form may be (1)

the change in volume of a gas with temperature.

applied directly to the surface to be treated by me-

Absolute temperatures are expressed either in de-

chanical pressure or compressed-air blast, as in cle-

grees Kelvin or in degrees Rankine, corresponding

aning building stone; (2) affixed to paper or textile

respectively to the centigrade and Fahrenheit scales.

backing after the particles have been coated with an

Temperatures in Kelvins are obtained by adding 273

adhesive; or (3) mixed with a bonding agent such as

to the centigrade temperature (if above 0C) or sub-

sodium silicate or clay, the particles being com-

tracting the centigrade temperature from 273 (if

pressed into a wheel rotated by a power-driven shaft.

below 0C). Degrees Rankine are obtained by sub-

Aluminum grinding wheels are fabricated by bond-

tracting 460 from the Fahrenheit temperature.

ing industrial diamonds with fluorocarbon polymer

(“Teflon”). The process involves reaction of fluo-

rine with the surfaces of the diamonds, chemical

absolute zero. Temperature at which the vol-

bonding of the fluorinated diamonds to the fluoro- ume of a perfect gas theoretically becomes zero and

carbon, and further chemical bonding of the result- all thermal motion ceases: −273.13C or −459.4F.

3 ABUNDANCE

absorbent. (1) Any substance exhibiting the Absorption processes occur throughout the electro-

property of absorption, e.g., absorbent cotton, so magnetic spectrum, ranging from the ␥ region (nu-

clear resonance absorption or the Mossbauer effect)

made by removal of the natural waxes present. (2) A

to the radio region (nuclear magnetic resonance). In

material that does not transmit certain wavelengths

practice, they are limited to those processes that are

of incident radiation.

followed by the emission of radiant energy of great-

See absorption (1); absorption (2).

er intensity than that which was absorbed. All ab-

sorption processes involve absorption of a photon by

absorptiometer. An instrument for determining

the substance being analyzed. If it loses the excess

the solubility of a gas in a liquid.

energy by emitting a photon of less energy than that

absorbed, fluorescence or phosphorescence is said

absorption. (1) In chemical terminology, the

to occur, depending on the lifetime of the excited

penetration of one substance into the inner structure

state. The emitted energy is normally studied. If the

of another, as distinguished from adsorption, in

source of radiant energy and the absorbing species

which one substance is attracted to and held on the

are in identical energy states (in resonance) the ex-

surface of another. Physicochemical absorption oc-

cess energy is often given up by the nondirectional

curs between a liquid and a gas or vapor, as in the

emission of a photon whose energy is identical with

operation known as scrubbing, in which the liquid is

that absorbed. Either absorption or emission may be

called an absorption oil; sulfuric acid, glycerol, and

studied, depending upon the chemical and instru-

some other liquids absorb water vapor from the air

mental circumstances. If the emitted energy is stud-

under certain conditions. Physiological absorption

ied, the term resonance fluorescence is often used.

takes place via porous tissues, such as the skin and

However, if the absorbing species releases the ex-

intestinal walls, which permit passage of liquids and

cess energy in small steps by intermolecular colli-

gases into the bloodstream.

sion or some other process, it is commonly under-

See adsorption; hygroscopic. (2) In physical termi-

stood that this phenomenon falls within the realm of

nology, retention by a substance of certain wave-

absorption spectroscopy. The terms absorption

lengths of radiation incident upon it, followed either

spectroscopy, spectrophotometry, and absorptime-

by an increase in temperature of the substance or by

try are often used synonymously. Most absorption

a compensatory change in the energy state of its

spectroscopy is done in the ultraviolet, visible, and

molecules. The UV component of sunlight is ab-

infrared regions of the electromagnetic spectrum.

sorbed as the light passes through glass and some

See emission spectroscopy; infrared spectroscopy.

organic compounds, the radiant energy being trans-

formed into thermal energy. The radiation-absorp-

tive capacity of matter is utilized in analytical chem-

absorption tower. (scrubber; Paulson tower).

istry in various types of absorption spectroscopy. (3)

A device used for gas purification by absorption of

In physical chemistry, the ability of some elements

gas impurities in a liquid.

to pick up or “capture” thermal neutrons produced in

nuclear reactors as a result of fission. This is due to

ABS resin. Any of a group of tough, rigid ther-

the capture cross section of their atoms, which is

moplastics that derive their name from the initial

measured in units called barns; elements of particu-

letters of the monomers which produce them.

larly high neutron absorption capability are cadmi-

um and boron.

abstraction reaction. A reaction that removes

an atom from a structure.

absorption (biology). Transport of the prod-

ucts of digestion from the intestinal tract into the

abundance. The relative amount (% by weight)

blood.

of a substance in the earth’s crust, including the

atmosphere and the oceans. (1) The abundance of

absorption band. The range of wavelengths

the elements in the earth’s crust is:

absorbed by a molecule; for example, absorption in

the infrared band from 2.3 to 3.2 ␮m indicates the

Rank Element % by wt.

presence of OH and NH groups, while in the band

from 3.3 to 3.5 indicates aliphatic structure. Atoms

1 Oxygen 49.2

absorb only a single wavelength, producing lines,

2 Silicon 25.7

such as the sodium D line.

3 Aluminum 7.5

See spectroscopy; resonance (2); ultraviolet absorb-

4 Iron 4.7

er; excited state.

5 Calcium 3.4

6 Sodium 2.6

absorption oil. See absorption (1).

7 Potassium 2.4

8 Magnesium 1.9

absorption spectroscopy. An important tech- 9 Hydrogen 0.9

nique of instrumental analysis involving measure- 10 Titanium 0.6

ment of the absorption of radiant energy by a sub- 11 Chlorine 0.2

stance as a function of the energy incident upon it. 12 Phosphorus 0.1

4“ABZOL”

“Accepta” [Accepta]. TM for a rig wash con-

Rank Element % by wt.

centrated detergent miscible with fresh or sea

waters.

13 Manganese 0.1

Use: Cleaning in the shipping industry.

14 Carbon 0.09

15 Sulfur 0.05

“Accepta 3538” [Accepta]. TM for an emul-

16 Barium 0.05

sifying bilge cleaner and degreaser.

all others 0.51

(2) The percentages of inorganic compounds in the

“Accepta 3547” [Accepta]. TM for a water

earth’s crust, exclusive of water, are:

stain and scale remover.

(1) SiO

55 (2) Al

15 (3) CaCO

8.8

Use: For steel, wood, glazed surfaces, toilet bowls,

(4) MgO 1.6 (5) Na

O 1.6 (6) K

O 1.9

baths and terrazo.

(3) The most abundant organic materials are cellu-

lose and its derivatives, and proteins.

acceptability (foods). See organoleptic.

Note: In the universe as a whole, the most abundant

element is hydrogen.

acceptable risk. A concept that has developed

in recent years, especially in connection with toxic

“Abzol” [Albemarle]. TM for a solvent cleaner

substances (insecticides, mercurials, carcinogens),

that can be used in place of