A group of businesses specializing in the
making of similar products or the providing of similar services. Farming,
manufacturing, government, and retailing are some examples. In many
books, "industry" is used synonymously with "manufacturing", e.g., The "Industrial
Revolution" was a revolution in manufacturing technologies using extensive
mechanization of manual labor in factories, later using steam power. It began
in Great Britain in the 18th century and later advanced into Europe and the United States.
It would be less confusing and more consistent to call this a "Manufacturing Revolution".
This definition of "industry" used here is consistent with the U.S. DOL (Department of
Labor) government OSHA
(Occupational Safety and Health Administration) SIC (Standard Industrial Classification)
An ink is a liquid containing various pigments or dyes or both and used for coloring
a surface to render an image or text. Inks are used in drawing and writing, but mostly
Early varieties of ink include Indian ink, various natural dyes made from metals, the husk, or
the outer covering of nuts or seeds, sea animals like the squid, known as sepia, and linseed
and soybean oils. Walnut ink and iron-gall nut ink were made and used by many
of the early masters to obtain the golden brown ink used for drawing.
Pigmented inks contain other materials to ensure adhesion of the pigment to the surface
to prevent its being removed by abrasion. These
materials are typically referred to as resins in solvent-based inks and binding agents in
water-based inks. Pigmented inks have the advantage when printing on paper that
the pigment stays on the surface of the paper, which is desirable, because when more ink
stays on the surface of the paper, less ink needs to be used to create the same intensity of
colour. Dyes, however, are generally much stronger and can produce more color of
a given density. However, because dyes are dissolved in liquid, they have
a tendency to soak into paper, thus making the ink less efficient and also potentially allowing
the ink to bleed at the edges, producing unsightly and poor-quality printing.
To circumvent this problem, dye-based inks are made with solvents that dry rapidly or are
used with quick-drying methods of printing, such as blowing hot air on the fresh print.
Other methods, particularly suited to inks that are used in machines, such as ink- jet printers,
which must conform to tighter toxicity and emission controls, include
covering the paper with a charged coating. If the dye has the opposite charge, then it
is attracted to and retained by this coating while the solvent soaks into the paper.
Cellulose, the material that paper is made of, is also naturally charged, and so an ink
made with a compound such as polyvinyl pyrrolidone gives the dye the opposite charge
as the paper surface to retain the ink at the paper surface.
An additional advantage of dye-based ink systems is that the dye molecules interact
chemically with other ink ingredients. This means that they can benefit more than
pigmented ink from optical brighteners and color-enhancing agents designed to increase
the intensity and appearance of dyes. Because dyes get their color from the
interaction of electrons in their molecules, the way in which the electrons can move is
determined by the charge and extent of electron delocalization in the other ink ingredients.
The color emerges as a function of the light energy that falls on the dye. Thus,
if an optical brightener or color enhancer absorbs light energy and emits it through or with the
dye, the appearance changes, as the spectrum of light re-emitted to the observer changes.
A disadvantage of dye-based inks is that they can be more susceptible to fading,
especially when exposed to ultraviolet light from the sun.
- Isomer (chemical)
Chemical isomers are molecules with the same chemical formula, i.e, the same numbers of
atoms, but with different arrangements among the atoms. There are 3 different
kinds of isomers:
(1) Structural isomers have the atoms joined together in different covalent structures, i.e., the
links among the atoms are different.
(a) Structure of carbon skelton.
(b) Position of functional group.
(c) Different functional group.
(2) Geometric isomers have the same structure of atoms or
functional groups, but they are arranged diffently about a double bond, usually C=C.
(3) Enantiomers (optical isomers) have the atoms in the same
structure, but one is a mirror-image of the other, i.e., one is right-handed and the other is
Isomers (2) and (3) are called stereoisomers. They have the same structure and bond
order, but the atoms are arranged differently in space.