Monday, September 24, 2007

Jewellery and society

Jewellery is factually any piece of fine material used to decorate oneself. Although in earlier times jewellery was created for more convenient uses, such as wealth storage and pinning clothes together, in recent times it has been used almost completely for beautification. The first pieces of jewellery were made from likely materials, such as bone and animal teeth, shell, wood and engraved stone. Jewellery was often made for people of high importance to show their status and, in many cases, they were covered with it.Jewellery is made out of almost every material recognized and has been made to garnish nearly every body part, from hairpins to toe rings and many more types of jewellery. While high-quality and artistic pieces are made with gemstones and valuable metals, less pricey costume jewellery is made from less-valuable materials and is mass-produced.Form and function Kenyan man exhausting tribal beads.Over time, jewellery has been used for a number of reasons: Currency, wealth display and storage, purposeful Symbolism Protection and Artistic display Most cultures have at some point had a practice of observance large amounts of wealth stored in the form of jewellery. Numerous cultures move wedding dowries in the form of jewelry, or create jewelry as a means to store or display coins. on the other hand, jewellery has been used as a currency or trade good; a mostly poignant example being the use of slave beads.

In creating jewellery, a variety of gemstones, coins, or other valuable items can be used, often set into precious metals. Common expensive metals used for modern jewellery include gold, platinum or silver, although alloys of nearly every metal known can be encountered in jewellery -- bronze, for example, was common in Roman times. Most gold jewellery is made of an alloy of gold, the purity of which is affirmed in karats, indicated by a number followed by the letter K. For example, ordinary gold jewellery ranges from 10K (41.7% pure gold) to 22K (91.6% pure gold), while 24K (99.9% pure gold) is considered too soft for jewellery use.
Platinum alloys variety from 900 (90% pure) to 950 (95.0% pure). The silver used in jewellery is usually sterling silver, or 92.5% fine silver.Other generally used materials include glass, such as merged glass or enamel; wood, often carved or turned; shells and other natural animal substances such as bone and ivory; natural clay, polymer clay, and even plastics.

Monday, September 10, 2007


It is the visual perceptual property corresponding in humans to the categories called red, yellow, white, etc. Color derives from the spectrum of light distribution of light energy versus wavelength interacting in the eye with the spectral sensitivities of the light receptors. Color categories and physical specifications of color are also associated with objects, materials, light sources, etc., based on their physical properties such as light absorption, reflection, or emission spectra.

Typically, only features of the composition of light that are detectable by humans wavelength spectrum from 400 nm to 700 nm, roughly are included, thereby objectively relating the psychological phenomenon of color to its physical specification. Since perception of color stems from the varying sensitivity of different types of cone cells in the retina to different parts of the spectrum, colors may be defined and quantified by the degree to which they stimulate these cells. These physical or physiological quantifications of color, however, do not fully explain the psychophysical perception of color appearance.

The science of color is sometimes called chromatics. It includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range that is, what we commonly refer to simply as light.

Sunday, September 02, 2007


In a computer CPU, an accumulator is an inventory in which intermediary arithmetic and logic results are stored. Without a register like an accumulator, it would be essential to write the result of each calculation to main memory, possibly only to be read right back again for use in the next operation. Access to main memory is slower than access to a register like the accumulator because the technology used for the huge main memory is slower than that used for a register.