Sunday, February 17, 2008

Line Printers

Line printers, as the name implies, print an whole line of text at a time. Three principal designs are existed. In drum printers, a drum carries the whole character set of the printer repeated in each column that is to be printed. In chain printers (also called as train printers), the character set is arranged multiple times around a chain that travels horizontally past the print line. In either case, to print a line, specifically timed hammers strike against the back of the paper at the exact moment that the correct character to be printed is passing in front of the paper. The paper presses forward touching a ribbon which then presses against the character form and the impression of the character form is printed onto the paper.

Comb printers characterize the third major design. These printers were a hybrid of dot matrix printing and line printing. In these printers, a comb of hammers printed a part of a row of pixels at one time (for example, every eighth pixel). By shifting the comb back and forth slightly, the complete pixel row could be printed (continuing the example, in just eight cycles). The paper then highly developed and the next pixel row was printed. Because far less motion was involved than in a conservative dot matrix printer, these printers were very fast compared to dot matrix printers and were competitive in speed with formed-character line printers while also being able to print dot-matrix graphics.

Line printers were the fastest of all impact printers and were used for largeness printing in large computer centres. They were almost never used with personal computers and have now been replaced by high-speed laser printers.

The heritage of line printers lives on in many computer operating systems, which use the abbreviations "lp", "lpr", or "LPT" to refer to printers.

Sunday, February 10, 2008

Modern Print Technology

Toner-Based Printers

Toner-based printers work using the Xerographic standard that is at work in most photocopiers: by adhering toner to a light-sensitive print drum, then using static electricity to transfer the toner to the printing medium to which it is fused with heat and pressure.

The most regular type of toner-based printer is the laser printer, which uses precision lasers to cause adherence. Laser printers are known for high quality prints, good print speed, and a low (Black and White) cost-per-copy; they are the most general printer for many general-purpose office applications. They are far less frequently used as consumer printers due to a high initial cost.

Laser printers are existing in both color and monochrome varieties.

Another toner based printer is the LED printer which uses an array of LEDs as an alternative of a laser to cause toner adhesion to the print drum.

Recent research has also indicated that Laser printers produce potentially dangerous ultrafine particles, possibly causing health problems associated with respiration. The degree of particle emissions varies with age, model and design of each printer but is commonly proportional to the amount of toner required. Furthermore, a well ventilated workspace would allow such ultrafine particles to disperse thus reducing the health side effects.

Tuesday, February 5, 2008

System-of-Systems Engineering (SoSE)

System-of-Systems Engineering (SoSE) is a set of developing processes and methods for manipulative and implementing solutions to System-of-Systems problems. SoSE is moderately new term being used in Department of Defense applications, but is increasingly being applied to non-military/security related problems (e.g., transportation, healthcare, Internet, search and rescue, space exploration). SoSE is more than systems engineering of multifaceted systems because design for System-of-Systems problems is performed under some level of uncertainty in the requirements and the constituent systems, and it involves considerations in multiple levels and domains (as per Ref. 2 and 3). Whereas SE focuses on building the system right, SoSE focuses on choosing the right system(s) to gratify the requirements.

Sunday, January 27, 2008

France And Italy Coins

France

In France the sou (until 1715 sol) was the first name of a coin. It was initial minted in gold, from the 1200s in silver and during the 1700s in copper. The sou tournois was a 12-denier coin, one-twentieth of the livre tournois (Tournois pound), although the sou parisis was a 15-denier coin. After decimalisation in France, the sou became the forename for a five-centime coin, one-twentieth of the French franc(Until the late 1960s, the expression "20 sou" was a synonym of 1 Franc).

To this day, sou is used as jargon for currency, as in j'ai pas de sous. "I'm broke", "I haven't got two bob to rub together".

Sou of copper, coined 1767 designed for Louis XV of France

Italy

The first name of the medieval Italian soldo (plural soldi) was derived from solidus.

Thursday, January 17, 2008

Solidus coin

A solidus (the Latin word for solid) was initially a gold coin issued by the Romans.

Julian solidus, ca. 361.It was introduced by Constantine I in the AD 309–10, and was used from beginning to end the Byzantine Empire until the 10th century AD. The coin replaced the aureus as the major gold coin of the Roman Empire.

The name solidus had beforehand been used by Diocletian (284-305) for the gold coin that he introduced, which is different from the solidus introduced by Constantine. The coin was struck at a theoretical worth of 1/72 of a Roman pound (about 4.5 grams). Solidi were wider and thinner than the aureus, with the exclusion of some dumpy issues from the Byzantine Empire. The weight and fineness of the solidus remained moderately constant throughout its long production, with few exceptions. Fractions of the solidus recognized as semisses (half-solidi) and tremissis (one-third solidi) were also produced.

Avitus tremissis, ca. 456.The word soldier is eventually derived from solidus, referring to the solidi with which soldiers were paid.

Wednesday, January 9, 2008

Beaver Coins

Beaver Coins, also identified in Pioneer days as Beaver Money, were gold coins temporarily minted by the Provisional Government of the Oregon Territory in the late 1840's. The coins were accessible in $5 and $10 dollar denominations. Their name comes from the well-known Beaver depicted on the face of the coins. Today these coins are moderately rare and valuable.

The influx of settlers into the Oregon Country produced a scarcity of circulating currency. The population at the moment in time resorted to using gold specks or minting their own gold coins for utilize in trading. Many settlers began lobbying the territory's new government to accurate this situation.

The Provisional Territorial Legislature at Champoeg then gave the endorsement for the Oregon Exchange Company to mint currency. Although the Oregon Exchange Company was generally a private organization, the territorial legislature set the coin's values, authorized a mint, and appointed the officers to the mint.

Sunday, December 30, 2007

British coin Triple Unite

The Triple Unite, valued at sixty shillings, 60/- or three pounds, was the peak British denomination to be produced in the era of the hammered coinage. It was only produced during the Civil War, at King Charles I's mints at Oxford and, on the odd occasion, at Shrewsbury in 1642. It weighed 421 grains, or immediately over seven-eighths of a troy ounce.

The gold coins are unquestionably magnificent pieces of work, and they show the king holding a sword and an olive branch on the obverse, signifying his wish for peace rather than war.

The tremendously rare Shrewsbury-produced coin shows, on the obverse, a plume behind the kings' head surrounded by the legend CAROLUS DG MAG BRIT FRAN ET HIBER REX -- Charles by the grace of God King of Great Britain France and Ireland.

The reverse shows the legend RELIG PROT LEG ANG LIBER PAR in two lines -- The religious conviction of the Protestants, the laws of England and the liberty of Parliament, with three plumes and the value numeral III above the announcement and the year 1642 below it, the whole being surrounded by the legend EXURGAT DEUS DISSIPENTUR INIMICI - Let God arise and His enemies be scattered.

The Oxford issues are extremely similar to the Shrewsbury one, except that the legend on the reverse appears in three lines rather than two, and the obverse legend appears as CAROLUS DG MAG BRIT FR ET HIB REX. Oxford coins come into view with slight design differences in each year of 1642, 1643, and 1644.