Wednesday, May 13, 2020

Beers Law Definition and Equation

Beers Law is an equation that relates the attenuation of light to properties of a material. The law states that the concentration of a chemical is directly proportional to the absorbance of a solution. The relation may be used to determine the concentration of a chemical species in a solution using a colorimeter or spectrophotometer. The relation is most often used in UV-visible absorption spectroscopy. Note that Beers Law is not valid at high solution concentrations. Other Names for Beers Law Beers Law is also known as the Beer-Lambert Law, the Lambert-Beer Law, and the  Beer–Lambert–Bouguer Law. The reason there are so many names is because more than one law is involved. Basically, Pierre Bouger discovered the law in 1729 and published it in Essai doptique sur la gradation de la lumià ¨re. Lambert quoted Bougers discovery in his Photometria in 1760, saying absorbance of a sample is directly proportional to the path length of light. Even though Lambert didnt claim discovery, he was often credited with it. August Beer discovered a related law in 1852. Beers Law stated that the absorbance is proportional to the concentration of the sample. Technically, Beers Law relates only to concentration, while the Beer-Lambert Law relates absorbance to both concentration and sample thickness. Key Takeaways: Beer's Law Beers Law states that the concentration of a chemical solution is directly proportional to its absorption of light.The premise is that a beam of light becomes weaker as it passes through a chemical solution. The attenuation of light occurs either as a result of distance through solution or increasing concentration.Beers Law goes by many names, including the Beer-Lambert Law, Lambert-Beer Law, and Beer-Lambert-Bouguer Law. Equation for Beers Law Beers Law may be written simply as: A ÃŽ µbc where  A is absorbance (no units)ÃŽ µ is the molar absorptivity with units of L mol-1  cm-1 (formerly called the extinction coefficient)b is the path length of the sample, usually expressed in cmc is the concentration of the compound in solution, expressed in mol L-1 Calculating the absorbance of a sample using the equation depends on two assumptions: The absorbance is directly proportional to the path length of the sample (the width of the cuvette).The absorbance is directly proportional to the concentration of the sample. In this example of the Beer-Lambert law, a green laser is attenuated as it passes through a solution of Rhodamine 6G. Amirber How to Use Beers Law While many modern instruments perform Beers Law calculations by simply comparing a blank cuvette with a sample, its easy to prepare a graph using standard solutions to determine the concentration of a specimen. The graphing method assumes a straight-line relationship between absorbance and concentration, which is valid for dilute solutions.   Beers Law Example Calculation A sample is known to have a maximum absorbance value of 275 nm. Its molar absorptivity is 8400 M-1cm-1. The width of the cuvette is 1 cm. A spectrophotometer finds A 0.70. What is the concentration of the sample? To solve the problem, use Beers Law: A ÃŽ µbc 0.70 (8400 M-1cm-1)(1 cm)(c) Divide both sides of the equation by [(8400 M-1 cm-1)(1 cm)] c 8.33 x 10-5 mol/L Importance of Beers Law Beers Law is especially important in the fields of chemistry, physics, and meteorology. Beers Law is used in chemistry to measure the concentration of chemical solutions, to analyze oxidation, and to measure polymer degradation. The law also describes the attenuation of radiation through the Earths atmosphere. While normally applied to light, the law also helps scientists understand the attenuation of particle beams, such as neutrons. In theoretical physics, the Beer-Lambert Law is a solution to the Bhatnagar-Gross-Krook (BKG) operator, which is used in the Boltzmann equation for computational fluid dynamics. Sources Beer, August. Bestimmung der Absorption des rothen Lichts in farbigen Flà ¼ssigkeiten (Determination of the absorption of red light in colored liquids). Annalen der Physik und Chemie, vol. 86, 1852, pp. 78–88.Bouguer, Pierre. Essai doptique sur la gradation de la lumià ¨re. Claude Jombert, 1729 pp. 16–22.Ingle, J. D. J., and S. R. Crouch. Spectrochemical Analysis. Prentice Hall, 1988.Lambert, J. H. Photometria sive de mensura et gradibus luminis, colorum et umbrae [Photometry, or, On the measure and gradations of light, colors, and shade]. Augsburg (Augusta Vindelicorum). Eberhardt Klett, 1760.Mayerhà ¶fer, Thomas Gà ¼nter, and Jà ¼rgen Popp. Beers law - why absorbance depends (almost) linearly on concentration. Chemphyschem, vol. 20, no. 4, December 2018. doi:10.1002/cphc.201801073

Wednesday, May 6, 2020

Office Depot Free Essays

â€Å"Office Depot† The First Office Depot opened in 1986 in Lauderdale Lakes, Florida. The Office Depot is a global supplier of office products and services and has experienced a dramatic growth process over the past twenty-five years. In 1990 the Office Depot Companies bought â€Å"The Office Club Inc. We will write a custom essay sample on Office Depot or any similar topic only for you Order Now †, and immediately became the largest office retailer in North America. Having built its business within the United States and having secured a firm business foundation, Office Depot expanded internationally in 1992. In 1996, Office Depot took its’ catalog and delivery service(s) online. Office Depot opened about 125 stores between the years 2000-2004. With the economic downturn of 2007, new strategies had to be put in place, and by 2009, 125 stores in international markets were closed. Office Depot exited the Japanese market entirely. Today, Office Depot provides office supplies and services through 1,678 retail stores worldwide, a dedicated sales force, top-rated catalogs, and global e-commerce operations. Office Depot has annual sales of $11. 5 billion, employs roughly 39,000 employees, and serves customers in 61 countries. Their distribution channels include stores, direct mail, contract delivery, the internet, and B2B e-commerce. Viking Office Products, their wholly owned subsidiary, currently operates one of the industry’s leading direct mail marketers of office products worldwide. The competitive strategy that the Office Depot will approach is a â€Å" best-cost provider strategy† to become #1 in the office supply business. For online purchases, customers will be offered free shipping on any purchase over $25. 00. A promotional discount will be applied for 20% off, on the next purchase for every $100. 00 spent by the customer. There will be a rewards program for customers and businesses that continue to shop with Office Depot. Based on the number of office supply items purchased, the next item will be free and additional discounts will be applied to future purchases. After the retail store(s), prices will be lowered on items bought primarily by back-to-school customers and also year-round casual shoppers items. The retail stores will monitor active inventory for excess quantities and slow moving items and record adjustments as necessary to lower the price(s) if the anticipated realizable amount is below cost. Also, estimate and determine what items to stock and at what level, and what items to discontinue and how to value them prior to sale. The large-format retail stores will be reduced to half of the current square-footage, and staff will focus only on supplying consistently purchased merchandise. Items that tend to sit dormant at retail will be provided online only. If a retail store cannot maintain projected sales quotas, the store will be closed in that market area. New government contracts will be provided at 20% discount based on the number of office supplies purchased. Office Depot will retain business with local, state, and federal governments’ and non-profit organizations contracts by offering a lower cost than other competitors. Office Depots long term strategic direction is to be consumer focused in terms of product assortment, store layouts, new service offerings, and compelling pricing that sends a positive value message to its’ customers. This falls in line with the â€Å"best cost provider strategy† giving customers more value for the money while satisfying buyers’ expectations on key quality/features/performance/service attributes beating their price expectations. One of the main ways that Office Depot has responded was with its’ Magellan innovation, a three-year program which significantly enhanced IT capabilities. The new system will provide such benefits as improved forecasting, better support for planning, and improved profitability. This can be achieved through better utilization of store space, better pricing and data integrity, better stocking, and reduced inventory with the end results benefiting the customer. In 2011 Office Depot announced that it is boosting their capital expenditure budget for 2012 to approximately $160 million, with a heavy emphasis on e-commerce and other IT investments. The retailers’ digital investments will be particularly important given its plans to shrink both the average size of its brick-and-mortar stores and its product assortments. Office Depots’ e-commerce sales have become an integral part of the company. Office Depot is the number (2) U. S. e-commerce retailer, second only to Amazon. com Inc. Office Depots’ aggressive Internet strategy has also generated twice the e-commerce sales of its’ rival Staples Inc. Office Depot SWOT Analysis Strengths: * Strong private label product line increases sales nationally and internationally. * Large, diverse customer base (individuals, small business, and large businesses) both nationally and overseas. * Company transitioning to smaller store format will increase presence in high growth markets. * As a direct result of negative economy, company has shuttered underperforming stores. * Cash liquid business with total assets of over four- billion dollars U. S. Weaknesses: * Little opportunity for real growth in U. S. market due to over-saturation. * Increases in competition in U. S. products market, combined with a reliance on low profit- margin electronics. * Due to the downturn of the economy coupled with continued nationally high unemployment rates†¦ sales, profits, and some business markets have diminished. * Accusations of overcharging Government Contract customers have been made public. Opportunities: * Money spent on office equipment and related items increasing among small and medium businesses. Increased ability to enter into more densely populated areas, while also reducing costs. * Increased opportunities of acquisitions due to strong cash reserves. * Increasing line of private label products geared towards â€Å"green† technology. Threats: * The global financial downturn. * High unemployment, coupled with an increase in office vacancies, compounded by low consumer confidence results in decreased spending. * Low c ost/low quality imported equipment and products can lead to quality related issues. * Low switching costs increases competition and can lead to â€Å"price wars†. How to cite Office Depot, Papers

Tuesday, May 5, 2020

Mongol Movie free essay sample

Genghis Khan who was a slave before going on to conquer half the world including Russia in 1206. Mongol begins as TemÃ'ËœJin (Genghis) is a young boy, searching for his future bride with his father, a khan. Throughout the film, the audience is shown all of the trials and tribulations that TemÃ'ËœJin had to go through in order to rise from slavery into the position of khan. As the film begins, the audience is shown the rough face of a prisoner being mocked in his cell in the Chinese kingdom Tangut. This prisoner is TemÃ'ËœJin. From this point onward, the movie is somewhat told in flashback by years. Leaving on an expedition as a young boy, TemÃ'ËœJin travels along with his father YesÃ'Ëœgei to select a girl as his future wife. TemÃ'ËœJin meets and chooses BÂ ¶rte although his father wishes him to choose a mate from the Merkit tribe. We will write a custom essay sample on Mongol Movie or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page TemÃ'ËœJin convinces his father to allow him to choose BÂ ¶rte. He promises to return after five years to marry her. After leaving, YesÃ'Ëœgei is poisoned by a rival tribe and dies. Upon returning to their camp, TemÃ'ËœJin and his mother find one of his fathers warriors looting their possessions. The warrior tries to kill TemÃ'ËœJin, as he is a threat to his path to khan, but is reminded that it is against Mongol law to kill a child. He promises to return in the winter and kill the boy as a teen. TemÃ'ËœJin is shown throughout his teen years running from the warrior and his men in order to survive. Throughout the movie, TemÃ'ËœJin is seen praying to the Mongol god of the sky during hard times. One day he is found in the snow by a boy his age named Jamukha. They certify their friendship by becoming blood brothers. TemÃ'ËœJin is then captured by the warrior twice, and is able to escape both times, the second time finding BÂ ¶rte and returning to his mother with her. The warrior manages to find and pursue the reunited couple. While an injured TemÃ'ËœJin is able to escape by BÂ ¶rte surrendering herself to the khan and his men, she is captured and taken to their tribe. TemÃ'ËœJin locates his blood brother, who is now a khan, and asks him to help him find his wife and get her back. After a successful attle and recovering a pregnant BÂ ¶rte, the couple and a few warriors head out, including 2 of Jamukhas. He warns TemÃ'ËœJin that this action will cost him. This is proven when Jamukhas birth brother is killed by one of TemÃ'ËœJin soldiers. Jamukha and TemÃ'ËœJin go to war. Outnumbered, TemÃ'ËœJins army is quickly defeated. Jamukha declares victory and decides to make TemÃ'ËœJin a slave rather than execute him. TemÃ'ËœJin is sold into slavery in the Tangut kingdom and is put on display as The Mongol who threatened to take down the Tangut kingdom which can be considered ajor foreshadowing. TemÃ'ËœJin promises to a monk to spare mercy upon a monastery in the kingdom after he takes over as khan, as long as the monk finds TemÃ'ËœJins wife and son. While the monk dies on the Journey