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A spreadsheet is a computer application that simulates a paper, accounting worksheet. It displays multiple cells that together make up a grid consisting of rows and columns, each cell containing alphanumeric text, numeric values or formulas. A formula defines how the content of that cell is to be calculated from the contents of any other cell (or combination of cells) each time any cell is updated. Spreadsheets are frequently used for financial information because of their ability to re-calculate the entire sheet automatically after a change to a single cell is made.
Visicalc is usually considered the first electronic spreadsheet (although this has been challenged), and it helped turn the Apple II computer into a success and greatly assisted in their widespread application. Lotus 1-2-3 was the leading spreadsheet when DOS was the dominant operating system. Excel now has the largest market share on the Windows and Macintosh platforms.
The word "spreadsheet" came from "spread" in its sense of a newspaper or magazine item (text and/or graphics) that covers two facing pages, extending across the center fold and treating the two pages as one large one. The compound word "spread-sheet" came to mean the format used to present book-keeping ledgersâ€”with columns for categories of expenditures across the top, invoices listed down the left margin, and the amount of each payment in the cell where its row and column intersectâ€”which were, traditionally, a "spread" across facing pages of a bound ledger (book for keeping accounting records) or on oversized sheets of paper ruled into rows and columns in that format and approximately twice as wide as ordinary paper.
Batch spreadsheet report generators
A batch 'spreadsheet' is indistinguishable from a batch compiler with added input data, producing an output report (i.e. a 4GL or conventional, non-interactive, batch computer program). However, this concept of an electronic spreadsheet was outlined in the 1961 paper "Budgeting Models and System Simulation" by Richard Mattessich. The subsequent work by Mattessich (1964a, Chpt. 9, Accounting and Analytical Methods) and its companion volume, Mattessich (1964b, Simulation of the Firm through a Budget Computer Program) applied computerized spreadsheets to accounting and budgeting systems (on mainframe computers programmed in FORTRAN IV). These batch Spreadsheets dealt primarily with the addition or subtraction of entire columns or rows (of input variables) - rather than individual 'cells'.
In 1962 this 'concept' of the spreadsheet (called BCL for Business Computer Language) was implemented on an IBM 1130 and in 1963 was ported to an IBM 7040 by R. Brian Walsh at Marquette University, Wisconsin. This program was written in Fortran. Primitive timesharing was available on those machines. In 1968 BCL was ported by Walsh to the IBM 360/67 timesharing machine at Washington State University. It was used to assist in the teaching of finance to business students. Students were able to take information prepared by the professor and manipulate it to represent it and show ratios etc. In 1964, A book entitled Business Computer Language written by Kimball, Stoffells and Walsh and both the book and program were copyrighted in 1966 and years later that copyright was renewed
In the late 60's Xerox used BCL to develop a more sophisticated version for their timesharing system.
LANPAR spreadsheet compiler
Key invention in the development of electronic spreadsheets was made by Rene K. Pardo and Remy Landau, who filed in 1971 on spreadsheet automatic natural order recalculation algorithm in 1970. While the patent was initially rejected by the patent office as being a purely mathematical invention, following 12 years of appeals, Pardo and Landau won a landmark court case at the CCPA (Predecessor Court of the Federal Circuit) overturning the Patent Office in 1983 - establishing that "something does not cease to become patentable merely because the point of novelty is in an algorithm." However, in 1995 the United States Court of Appeals for the Federal Circuit ruled the patent unenforceable.
The actual software was called LANPAR - LANguage for Programming Arrays at Random. This was conceived and entirely developed in the summer of 1969 following Pardo and Landau's recent graduation from Harvard University. Co-inventor Rene Pardo recalls that he felt that one manager at Bell Canada should not have to depend on programmers to program and modify budgeting forms, and he thought of letting users type out forms in any order and having computer calculating results in the right order. The software was developed in 1969.
LANPAR was used by Bell Canada, AT&T and the 18 operating telcos nationwide for their local and national budgeting operations. LANPAR was also used by General Motors. Its uniqueness was the incorporation of natural order recalculation, as opposed to left-to-right, top to bottom sequence for calculating the results in each cell that was used by Visicalc, Supercalc and the first version of Multiplan. Without natural order recalculation the users had to manually recalculate the spreadsheet as many times as necessary until the values in all the cells had stopped changing.
The LANPAR system was implemented on GE400 and Honeywell 6000 online timesharing systems enabling users to program remotely via computer terminals and modems. Data could be entered dynamically either by paper tape, specific file access, on line, or even external data bases. Sophisticated mathematical expressions including logical comparisons and "if/then" statements could be used in any cell, and cells could be presented in any order.
Autoplan/Autotab spreadsheet programming language
In 1968, three former employees from the General Electric computer co
Asbestos (from Greeká¼„ÏƒÎ²ÎµÏƒÏ„Î¿Ï‚ or asbestinon, meaning "unquenchable" or "inextinguishable") is a set of six naturally occurring silicate minerals exploited commercially for their desirable physical properties. They all have in common their asbestiform habit, long, (1:20) thin fibrous crystals. The inhalation of asbestos fibers can cause serious illnesses, including malignant lung cancer, mesothelioma (a formerly rare cancer strongly associated with exposure to amphibole asbestos), and asbestosis (a type of pneumoconiosis). Long exposure to high concentrations of asbestos fibers is more likely to cause health problems, as asbestos exists in the ambient air at low levels, which itself does not cause health problems. The European Union has banned all use of asbestos and extraction, manufacture and processing of asbestos products.
Asbestos became increasingly popular among manufacturers and builders in the late 19th century because of its sound absorption, average tensile strength, and its resistance to heat, electrical and chemical damage. When asbestos is used for its resistance to fire or heat, the fibers are often mixed with cement or woven into fabric or mats. Asbestos was used in some products for its heat resistance, and in the past was used on electric oven and hotplate wiring for its electrical insulation at elevated temperature, and in buildings for its flame-retardant and insulating properties, tensile strength, flexibility, and resistance to chemicals.
Types and associated fibers
Six minerals are defined by the United States Environmental Protection Agency as "asbestos" including that belonging to the serpentine class chrysotile and that belonging to the amphibole class amosite, crocidolite, tremolite, anthophyllite and actinolite. There is an important distinction to be made between serpentine and amphibole asbestos due to differences in their chemical composition and their degree of potency as a health hazard when inhaled. However asbestos and all commercial forms of asbestos (including chrysotile asbestos) are known to be human carcinogens based on sufficient evidence of carcinogenicity in humans.
Chrysotile, CAS No. 12001-29-5, is obtained from serpentinite rocks which are common throughout the world. Its idealized chemical formula is Mg(SiO)(OH). Chrysotile fibers are curly as opposed to fibers from amosite, crocidolite, tremolite, actinolite, and anthophyllite which are needlelike. Chrysotile, along with other types of asbestos, has been banned in dozens of countries and is only allowed in the United States and Europe in very limited circumstances. Chrysotile has been used more than any other type and accounts for about 95% of the asbestos found in buildings in America. Applications where chrysotile might be used include the use of joint compound. It is more flexible than amphibole types of asbestos; it can be spun and woven into fabric. The most common use is within corrugated asbestos cement roof sheets typically used for outbuildings, warehouses and garages. It is also found as flat sheets used for ceilings and sometimes for walls and floors. Numerous other items have been made containing chrysotile including brake linings, cloth behind fuses (for fire protection), pipe insulation, floor tiles, and rope seals for boilers.
Amosite, CAS No. 12172-73-5, is a trade name for the amphiboles belonging to the Cummingtonite-Grunerite solid solution series, commonly from Africa, named as an acronym from Asbestos Mines of South Africa. One formula given for amosite is Fe7Si8O22(OH)2. It is found most frequently as a fire retardant in thermal insulation products and ceiling tiles.
Crocidolite, CAS No. 12001-28-4 is an amphibole found primarily in southern Africa, but also in Australia. It is the fibrous form of the amphibole riebeckite. One formula given for crocidolite is Na2Fe2+3Fe3+2Si8O22(OH)2.
Notes: chrysotile commonly occurs as soft friable
Hypochlorite was first produced in 1789 by Claude Louis Berthollet in his laboratory on the quay Javel in Paris, France, by passing chlorine gas through a solution of sodium carbonate. The resulting liquid, known as "Eau de Javel" ("Javel water"), was a weak solution of sodium hypochlorite. However, this process was not very efficient and alternate production methods were sought. One such method involved the extraction of chlorinated lime (known as bleaching powder) with sodium carbonate to yield low levels of available chlorine. This method was commonly used to produce hypochlorite solutions for use as a hospital antiseptic which was sold under the trade names "Eusol" and "Dakin's solution".
Near the end of the nineteenth century, E. S. Smith patented a method of hypochlorite production involving hydrolysis of brine to produce caustic soda and chlorine gas which then mixed to form hypochlorite. Both electric power and brine solution were in cheap supply at this time, and various enterprising marketers took advantage of this situation to satisfy the market's demand for hypochlorite. Bottled solutions of hypochlorite were sold under numerous trade names; one such early brand produced by this method was called Parozone.
Today, an improved version of this method, known as the Hooker process, is the only large scale industrial method of sodium hypochlorite production. In this process sodium hypochlorite (NaOCl) and sodium chloride (NaCl) are formed when chlorine is passed into cold and dilute sodium hydroxide solution. It is prepared industrially by electrolysis with minimal separation between the anode and the cathode. The solution must be kept below 40 Â°C (by cooling coils) to prevent the undesired formation of sodium chlorate.
- Cl2 + 2 NaOH â†’ NaCl + NaOCl + H2O
Hence, chlorine is simultaneously reduced and oxidized; this process is known as disproportionation.
The commercial solutions always contain significant amounts of sodium chloride (common salt) as the main by-product, as seen in the equation above.
Sodium hypochlorite can be also made by electrolyzing saturated sodium chloride solution and the product can be tested by dropping hydrochloric acid to determine if it is successfully synthesized.
Packaging and sale
Household bleach sold for use in laundering clothes is a 3-6% solution of sodium hypochlorite at the time of manufacture. Strength varies from one formulation to another and gradually decreases with long storage.
A 12% solution is widely [http://www.awwa.org/publications/AWWAJournalArticle.cfm?itemnumber=40152&showLogin=N] used in waterworks for the chlorination of water and a 15% solution is more commonly used for disinfection of waste water in treatment plants. High-test hypochlorite (HTH) is sold for chlorination of swimming pools and contains approximately 30% calcium hypochlorite. The crystalline salt is also sold for the same use; this salt usually contains less than 50% of calcium hypochlorite. However, the level of active chlorine may be much higher.
It can also be found on store shelves in Daily Sanitizing Sprays, as the sole active ingredient at 0.0095%.
Sodium hypochlorite reacts with metals gradually, such as zinc, to produce the metal oxide or hydroxide:
- NaOCl + Zn â†’ ZnO + NaCl
It reacts with hydrochloric acid to release chlorine gas:
- NaOCl + 2 HCl â†’ Cl2 + H2O + NaCl
It reacts with other acids, such as acetic acid, to release hypochlorous acid:
- NaOCl + CH3COOH â†’ HClO + CH3COONa
It decomposes when heated or evaporated to form sodium chlorate and sodium chloride:
- 3 NaOCl â†’ NaClO3 + 2 NaCl
In reaction with hydrogen peroxide it gives off molecular oxygen:
- NaOCl + H2O2â†’ H2O + NaCl + O2â†‘
In household form, sodium hypochlorite is used for removal of stains from laundry. It is particularly effective on cotton fiber, which stains easily but bleaches well. Usually 50 to 250 mL of bleach per load is recommended for a standard-size washer. The properties of household bleach that make it effective for removing stains also result in cumulative damage to organic fibers such as cotton, and the useful lifespan of these materials will be shortened with regular bleaching. The sodium hydroxide (NaOH) that is also found in household bleach (as noted later) causes fiber degradation as well. It is not volatile, and residual amounts of NaOH not rinsed out will continue slowly degrading organic fibers in the presence of humidity. For these reasons, if stains are localized, spot treatments should be considered whenever possible. With safety precautions, post-treatment with vinegar (or another weak acid) will neutralize the NaOH, and volatilize the chlorine from residual hypochlorite. Old t-shirts and cotton sheets that rip easily demonstrate the costs of laundering with household bleach. Hot water increases the activity of the bleach, owing to the increased kinetic energy of the molecules.
A weak solution of 1% household bleach in warm water is used to sanitize smooth surfaces prior to brewing of beer or wine. Surfaces must be rinsed to avoid imparting flavors to the brew; these chlorinated byproducts of sanitizing surfaces are also harmful.
US Government regulations (21 CFR Part 178) allow food processing equipment and food contact surfaces to be sanitized with solutions containing bleach, provided that the solution is allowed to drain adequately before contact with food, and that the solutions do not exceed 200 parts per million
From Yahoo Answers
Answers:There are over 300 built in functions in Excel. Here is a link to an excellent site that has all kinds of good information: http://www.cpearson.com/excel/topic.aspx Any book by John Walkenbach is worth the money spent. He has books on all aspects of Excel, all versions.
Answers:how big can the cheat sheet be? some teachers say only one paper, and index card, etc. just write everything you think you would need to know on it and if you can only use an index card or something small, then write really small.
Answers:just enter the formulas in your calculator as programs. just go to prgm button and type all your formulas in. so if you forget...just go back to prgm, edit, and you'll see everything you typed in
Answers:learn the derivation for the formulas (how the formulas were formed). it may help you remember the formulas. another way to remember is simply repetition. keep writing down these formulas untill u have a good grasp over them.