<Body><script type="text/javascript"> function setAttributeOnload(object, attribute, val) { if(window.addEventListener) { window.addEventListener('load', function(){ object[attribute] = val; }, false); } else { window.attachEvent('onload', function(){ object[attribute] = val; }); } } </script> <div id="navbar-iframe-container"></div> <script type="text/javascript" src="https://apis.google.com/js/plusone.js"></script> <script type="text/javascript"> gapi.load("gapi.iframes:gapi.iframes.style.bubble", function() { if (gapi.iframes && gapi.iframes.getContext) { gapi.iframes.getContext().openChild({ url: 'https://www.blogger.com/navbar.g?targetBlogID\x3d26111537\x26blogName\x3dcailin+tools\x26publishMode\x3dPUBLISH_MODE_BLOGSPOT\x26navbarType\x3dBLUE\x26layoutType\x3dCLASSIC\x26searchRoot\x3dhttp://cailin3t8s.blogspot.com/search\x26blogLocale\x3den_US\x26v\x3d2\x26homepageUrl\x3dhttp://cailin3t8s.blogspot.com/\x26vt\x3d-1724646298308225044', where: document.getElementById("navbar-iframe-container"), id: "navbar-iframe" }); } }); </script>

Friday, April 14, 2006

Life Day



Life Day was the fictional Wookiee holiday celebrated by the inhabitants of Kashyyyk, featured in The Star Wars Holiday Special. Unlike most aspects of the normally well-crafted Star Wars Universe, Life acrobat distillerDay is utterly acrobat reader downloadexpedient, inserted into the show to provide a very basic goal adobe acrobat free downloadfor the heroes, and lend a bit of topical relevance to the material, which would otherwise adobe acrobat downloadbe completely inappropriate for a television holiday special. Holiday Special gives us some insight into the customs of Life Day. Chewbaccas wife prepares a feast, gifts are exchanged between acquaintances, acrobat reader free downloadacrobat reader downloadcandles are burned ritualistically, and Wookiees don red robes and join into groups tomek9lcpto observe the pessach69spday. Singing is involved.

Citric acid



Properties
General
Name Citric acid
Carbon6Hydrogen8Oxygen7
Atomic weight 192.13 atomic mass unit
Synonyms 2-hydroxy-1,2,3-propanetricarboxylic acid
CAS number 77-92-9
Phase behavior
Melting point 426 kelvin (153 celsius)
Thermal decomposition temperature 448 K (175°C)
Acid-base properties
Acidity constant 3.15
pKa2 4.77
pKa3 5.19
Solid properties
Standard enthalpy change of formation 1543.8 joule/mole (unit)
Standard molar entropy 252.1 J/mol·K
Heat capacity 226.5 J/mol·K
Density 1.665 ×103 kilogram/metre3
Safety
Acute effects Skin and eye irritant.
Chronic effects None.
More info
Properties C77929&Units SI NIST WebBook
MSDS Hazardous Chemical Database
SI units were used where possible. Unless otherwise stated, Standard temperature and pressure conditions were used. Organic table information
Citric acid is a weak organic chemistry acid found in citrus fruits. It is a good, natural preservative and is also used to add an acidic (sour) taste to foods and soft drinks. In biochemistry, it is important as an intermediate in the citric acid cycle and therefore occurs in the metabolism of almost all living things. It also serves as an environmentally friendly cleaning agent and acts as an antioxidant. Citric acid exists in a variety of fruits and vegetables, but it is most concentrated in lemons and lime (fruit)s, where it can comprise as much as 8% of the acrobat reader free downloaddry weight of the fruit. Citric acids chemical formula is CarbonHydrogenOxygen and its structure is shown at right. This structure is reflected in its IUPAC nomenclature name 2-hydroxyl group-1,2,3-propanetricarboxylic acid.

Properties

The physical properties of citric acid are summarized in the table at right. The acidity of citric acid results from the three carboxy groups COOH which can lose a proton in solution. If this happens, the resulting ion is the citrate ion. Citrates make excellent buffers for controlling the pH of acidic solutions. Citrate ions form salts called citrates with many metal ions. An important one is calcium citrate or sour salt, which is commonly used in the preservation and flavoring of food. Additionally, citrates can chelation acrobat reader downloadmetal ions, which gives them use as preservatives and water softeners. At room temperature, citric acid is a white crystalline powder. It can exist either in an anhydrous (water-free) form, or as a hydrate that contains one water molecule for every molecule of citric acid. The anhydrous form crystallizes from hot water, while the monohydrate forms when citric acid is crystallized from cold water. The monohydrate can be converted to the anhydrous form by heating it above 74°C. Chemically, citric acid shares the properties of other carboxylic acids. When heated above 175°C, it decomposes through the loss of carbon dioxide adobe acrobat downloadand water (molecule).

History

The discovery of citric acid has been credited to the 8th century Islamic alchemy Abu Musa Jabir Ibn Hayyan (Geber). How? Did he isolate it? More details would be helpful > Medieval scholars in Europe were aware of the acidic nature of lemon and lime juices, such knowledge is recorded in the 13th century encyclopedia Speculum Majus (The Great Mirror), compiled by Vincent of Beauvais. Citric acid was first isolated in 1784 by the Sweden chemist Carl Wilhelm Scheele, who crystallized it from lemon juice. Industrial-scale citric acid production began in 1860, based on the Italy citrus fruit industry. In 1893, C. Wehmer discovered that Penicillium mold could produce free adobe acrobatcitric acid from sugar. However, microbial production of citric acid did not become industrially important until World War I disrupted Italian citrus exports. In 1917, the United States food chemist James Currie discovered that certain strains of the mold Aspergillus niger could be efficient citric acid producers, and Pfizer began industrial-level production using this technique two years later.

Production

In this production technique, which is still the major industrial route to citric acid used today, cultures of Aspergillus niger are fed on sucrose to produce citric acid. After the mold is filtered out of the resulting solution, citric acid is isolated by precipitating it with lime (calcium hydroxide) to yield calcium citrate salt, from which citric acid is regenerated by treatment with sulfuric acid. Alternatively, citric acid is sometimes isolated from the fermentation broth by extraction with a hydrocarbon solution of the organic chemistry base (chemistry) trilaurylamine, followed by re-extraction from the organic solution by water.

Uses

Most citric acid is used as a flavoring and preservative in food and beverages, especially soft drinks. Citrate salts of various metals are used to deliver those minerals in a biologically available form in many dietary supplements. The buffering properties of citrates are used to control pH in household cleaners and pharmaceuticals. Citric acids ability to chelate metals gives it use in soaps and laundry detergents. By chelating the metals in hard water, it lets these cleaners produce foam and work better without need for water softening. Similarly, citric acid is used to regenerate the ion exchange materials used in water softeners by stripping off the accumulated metal ions as citrate complexes. It is used in the biotechnology and pharmaceutical industry to passivate high purity process piping in lieu of using nitric acid, since nitric is a hazardous disposal issue once it is used for this purpose, while citric is not. In the United Kingdom, pharmacies control the sale of Citric acid. Citric acid is a popular buffer used to increase the solubility of street heroin in Scotland. Single-use citric acid sachets have been used as an inducement to get heroin users to exchange their dirty needles for clean needles in an attempt to decrease the spread of AIDS and hepatitis. See the.pdf article here. Other acidifiers used for brown heroin are ascorbic acid, acetic acid, and lactic acid: in their absence, the drug abuser will often substitute lemon juice or vinegar.

Safety

Citric acid is recognized as safe for use in food by all major national and international food regulatory agencies. It is naturally present in almost all forms of life, and excess citric acid is readily metabolized download adobe acrobat readerand eliminated from the adobe acrobat free downloadbody. Contact with gijsg96ydry citric acid or with concentrated solutions can virgena2m0sresult in skin and eye irritation, so protective clothing should be worn when handling these materials.

Rio de Janeiro (state)



List of the states of Brazil by area > List of the states of Brazil by population >
Statistics
Capital:Rio de Janeiro
366.6 inh./km²
List of the states of Brazil by population density >
Timezone:GMT -3
ISO 3166-2:BR-RJ
Governor:Rosângela Matheus
Map
Rio de Janeiro is one of the 26 States of Brazil of Brazil (plus the Federal District). It has an area of 43,653km² and is situated on the southeastern coast. Its capital is the city of Rio de Janeiro, which was the colonys capital as of 1764 (the first being Salvador da Bahia), and the nations capital from 1822 to 1960. In the year 2000, the population was 12,807,706. Governor: Rosângela Matheus (since January 1, 2003). Lieutenant Governor: Luiz Paulo Conde (former mayor of Rio de Janeiro).

Flag

Here the flag can be seen with the eagle, symbol of Brazils royal family and Serra dos Órgãos in the back, which is visible from Rio de Janeiro in a clear day. The outer part of the coat of arms represents its agricultural richness, sugarcane (left) and coffee (right)

Location

This Brazilian state is in the east of the southeastern subdivision of Brazil, which also contains the states of São Paulo (state), Minas Gerais and Espírito Santo. It has as its limits: The Atlantic Ocean (E), the state of Espírito Santo (N), the acrobat reader downloadstate of Minas Gerais (N) and (W), and the state of São Paulo (state) (S).

Cities

Other cities adobe acrobat reader free downloadinclude:
Angra dos Reis
Aperibé
Araruama
Areal
Arma adobe acrobat reader free downloadão dos Búzios
Arraial do Cabo
Barra do Piraí
Barra Mansa
Belford Roxo
Bom Jardim
Bom Jesus do Itabapoana
Cabo Frio
Cachoeiras de Macacu
Cambuci
Campos dos Goytacazes
Cantagalo
Carapebus
Cardoso Moreira
Carmo
Casimiro de Abreu
Comendador Levy Gasparian
Concei adobe acrobat reader free downloadão de Macabu
Cordeiro
Duas Barras
Duque de Caxias
Engenheiro Paulo de Frontin
Guapimirim
Iguaba Grande
Itaboraí
Itaguaí
Italva
Itaocara
Itaperuna
Itatiaia
Japeri
Laje do Muriaé
Macaé
Macuco (Rio de Janeiro)
Magé
Mangaratiba
Maricá acrobat reader(Rio de Janeiro)
Mendes (Brazil)
Miguel Pereira
Miracema
Natividade
Nilópolis
Niterói
Nova Friburgo
Nova Igua adobe acrobat reader free downloadu
Paracambi
Paraíba do Sul
Parati
Paty do Alferes
Petrópolis
Pinheiral
Piraí
Porciúncula
Porto Real
Quatis Queimados
Quissamã
Resende
Rio Bonito
Rio Claro
Rio adobe acrobat downloaddas Flores
Rio das Ostras
Santa Maria Madalena
Santo Antônio de free adobe acrobatPádua
São Fidélis
São Francisco de acrobat reader free downloadItabapoana
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São João da Barra
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São José de Ubá
São José do Vale do Rio Preto
São Pedro da Aldeia
São Sebastião do Alto
Sapucaia
Saquarema
Seropédica
Silva Jardim
Sumidouro
Tanguá
Teresópolis
Trajano de Morais
Três Rios
Valen adobe acrobat reader free downloada
Varre-Sai
Vassouras
Volta Redonda

Ship model basin



A ship model basin may be either a physical basin or tank used to carry out hydrodynamics tests with ship models, or the organization (often a company) that owns and operates such a facility. In the second meaning, the company or authority is an engineering firm that acts as contractor to shipyards and provides hydrodynamic model tests and numerical calculations to support the design and development of ships and offshore structures. Its hydrodynamic test facilities include at least
A towing tank: This is a basin, several metres wide and hundreds of metres long, equipped with a towing carriage that runs on two rails on either side. The towing carriage can either tow the model or follow the self-propelled model and is equipped with computers and devices to register or control, respectively, magnitudes like speed, propeller thrust and torque, rudder angle etc. The towing tank serves for resistance and propulsion tests with towed and self-propelled ship models to determine how much power the engine will have to provide to achieve the speed laid down in the contract between shipyard and ship owner. The towing tank also serves to determine the manoeuvring behaviour in model scale. For this, the self-propelled model is exposed to a series of zig-zag manoeuvres at different rudder angle amplitudes. A post-processing by means of system identification results in a numerical model to simulate any other manoeuvre like Dieudonné spiral test or turning circles. Additionally, a towing tank can be equipped with a PMM (planar motion mechanism) or a CPMC (computerized planar motion carriage) to measure the hydrodynamic forces and moments on ships or submerged objects under the influence of oblique inflow and enforced motions. The towing tank can also be equipped with a wave generator to carry out seakeeping tests, either by simulating natural (irregular) waves or by exposing the model to a wave packet that yields the RAOs for all frequencies in one single test.
A cavitation tunnel to investigate propellers. This is a vertical water circuit with large diameter pipes. At the top, it carries the measuring facilities. A parallel inflow is established. With or without a ship model, the propeller, attached to a dynamometre, is brought into the inflow, and its thrust and torque is measured at different ratios of propeller speed (number of revolutions) to inflow velocity. A stoboscope synchronized with the propeller speed serves to visualize cavitation as if the cavitation bubble would not move. By this, one can observe if the propeller would be damaged by cavitation. To ensure similarity to the full-scale propeller, the pressure is lowered, and the gas content of the water is controlled.
Workshops: Ship model basins manufacture their ship models from wood or parrafine with a computerized milling machine. Some of them also manufacture their model propellers. Equipping the ship models with all drives and gauges and manufacturing equipment for non-standard model tests are the adobe acrobatmain tasks of the workshops. Some ship model basins have further facilities like:
A manoeuvring and seakeeping basin. It is wide enough to investigate arbitrary angles adobe acrobatbetween waves and ship model and to perform manoeuvres like turning circles, for which the towing tank is too narrow. However, some important manoeuvres acrobat distillerlike the spiral test still require even more space and still have to be simulated numerically after system identification.
An ice tank: To develop ice breaking vessels, this tank fulfills similar purposes as the towing tank does for open water adobe acrobat 70vessels. Resistance and required engine power as well as manoeuvring behaviour are determined depending on the ice thickness. Also ice forces on offshore structures can be determined. Ice layers are frozen with a special procedure to scale down pernelid07the ice crystals to model scale. Also tests in brash ice are performed. acrobat downloadAddiyionally, these companies or blytheh7twauthorities have CFD software and experience to simulate the complicated flow around ships and their rudders and propellers numerically. Todays state of the art does not yet allow to replace model tests by CFD acrobat readercalculations. One reason, but not the only one, is that elementization is still expensive. Also the lines design of some of the ships is carried out by the specialists of the ship model basin, either from the beginning or by optimizing the initial design obtained from the shipyard. The same applies to the design of propellers. The ship model basins worldwide are organized in the ITTC (International Towing Tank Conference) to standardize their model test procedures. Some of the most significant ship model basins are the David Taylor Model Basin in the United States and the HSVA in Hamburg, Germany.