Information reliability for academic research review and recommendations free essay sample

The difference and the importance of both Scholarly publication and popular research both go hand and hand while seeking information. While scholarly publication is one in which the content is written by experts in a particular field of study generally for the purpose of sharing original research or analyzing others findings. Scholarly work will thoroughly cite all source materials used and is usually subject to peer review prior to publication.Scholars share their findings with similar experts. Many conference proceedings are peer-reviewed. The major source for scholarly information, journal articles include background research, data, and analysis. These are written by the scholars who conducted the research. These articles summarize and synthesize information from multiple primary articles. They can identify themes and trends across research. These types of sources can also catch you up on the relevant research in an area.The key items to include authorship, verifiability, and accuracy of details, currency, publishing body, points of view bias, and referral literature. We will write a custom essay sample on Information reliability for academic research: review and recommendations or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page This means that resources you would find in a physical library such as books, magazines, journals, and multimedia have been converted into digital formats and stored in databases, allowing you to access them by going to our webpage on a computer.( Quick n Dirty ) Referrals refer to the authoring context of work, and it can be referred to as literature knowledge. Literature includes a bibliography, treatment of controversial subjects, use of new theory and display of schools of thought and proper attribution of related resources. Points of view show the level of neutrality of information .the presence of the publishing body is an indication that the work has been screened. Currency refers to information timelines in the work. Verifiability or accuracy of the information is based on research method used, outlined methodology, listed bibliography and use of non-published data in the resource.To be the most effective and efficient when finding resources that fit research needs, one must start by having a clearly defined topic. Pay close attention to the details of the assignment, and list any keywords or concepts that require scholarly research. Refer to the tips in the Ashford University Library video Quick and Dirty (2013) discussed above, to help save time and get the desired results quicker. Conducting scholarly research can be overwhelming and daunting at first, but by being able to recognize the difference between scholarly and popular research, remembering key steps to using the Ashford University Library, and knowing how to effectively and efficiently find resources that fit your research needs, sorting through the sea of resources will be a bree ze.

Mutual Intelligibility Definition and Examples

Mutual Intelligibility Definition and Examples Mutual Intelligibility is a situation in which two or more speakers of a language (or of closely related languages) can understand each other. Mutual intelligibility is a continuum (that is, a gradient concept), marked by degrees of intelligibility, not by sharp divisions. Example and Observations [W]hat allows us to refer to something called English as if it were a single, monolithic language? A standard answer to this question rests on the notion of mutual intelligibility. That is, even though native speakers of English vary in their use of the language, their various languages are similar enough in pronunciation, vocabulary, and grammar to permit mutual intelligibility. . . . Hence, speaking the same language does not depend on two speakers speaking identical languages, but only very similar languages.(Adrian Akmajian, Richard Demers, Ann Farmer, and Robert Harnish, Linguistics: An Introduction to Language and Communication. MIT Press, 2001) The Mutual Intelligibility Test [The] distinction between language and dialect is based on the notion [of] mutual intelligibility: Dialects of the same language should be mutually intelligible, while different languages are not. This mutual intelligibility, in turn, would then be a reflection of the similarities between different varieties of speech.Unfortunately, the mutual-intelligibility test does not always lead to clear-cut results. Thus Scots English may at first be quite unintelligible to speakers of the various varieties of Standard American English, and vice versa. True, given enough time (and goodwill), mutual intelligibility can be achieved without too much effort. But given an even greater amount of time (and goodwill), and a greater effort, also French might become (mutually) intelligible for the same speakers of English. In addition, there are cases like Norwegian and Swedish which, because they have different standard varieties and literary traditions, would be called different languages by most people, including linguists, even though the two standard languages are mutually quite intelligible. Here, cultural and sociolinguistic considerations tend to overrule the mutual intelligibility test.(Hans Henrich Hoch, Principles of Histoprical Linguistics, 2nd ed. Mouton de Gruyter, 1991) One-Way Intelligibility [A]nother problem regarding the use of mutual intelligibility as a criterion [for defining a language is] that it need not be reciprocal, since A and B need not have the same degree of motivation for understanding each other, nor need they have the same amount of previous experience of each others varieties. Typically, it is easier for non-standard speakers to understand standard speakers than the other way round, partly because the former will have had more experience of the standard variety (notably through the media) than vice versa, and partly because they may be motivated to minimise the cultural differences between themselves and the standard speakers (though this is by no means necessarily so), while standard speakers may want to emphasize some differences.(Richard A. Hudson, Sociolinguistics, 2nd ed. Cambridge University Press, 2001) Theres a fat man who comes in here with pills sometimes and I cant understand a word he says. I told him Ive got no problem with wherever he comes from but I have to be able to understand him. He understands what Im saying and he talks louder. I dont hear well, but it doesnt help anything for him to say whatever it is hes saying in a louder voice.​(Glen Pourciau, Gone. Invite. University of Iowa Press, 2008) Bidialectalism and Mutual Intelligibility in The Color Purple Darlie trying to teach me how to talk. . . . Every time I say something the way I say it, she correct me until I say it some other way. Pretty soon it feel like I cant think. My mind run up on a thought, git confuse, run back and sort of lay down. . . . Look like to me only a fool would want you to talk in a way that feel peculiar to your mind.(Celie in The Color Purple by Alice Walker, 1982.) Also Known As: interintelligibility

Global Warming. Western States Increasing Temperatures Research Proposal

Global Warming. Western States Increasing Temperatures - Research Proposal Example With the increasing nature of industrialization in the world, there has been increasing amount of carbon compounds and gases that have been released to the atmosphere (Montzaka, Dlogukencky, & Butler, 2011). These carbon gases constitute most of the green house gases, which have caused lots of havoc in changes of weather conditions and caused extensive changes in the climatic conditions of the world. Global warming has been found to cause the increase of world temperatures, thereby affecting the vegetation and the human activities, which the world population is indulged into. Global warming is also associated with natural disasters such as extended torrential rains, melting of ice in the arctic and Antarctic regions, which have increased levels of the oceanic waters. These climatic changes have caused extensive changes in the vegetation of the world leading to drought and conditions being experienced in most regions of the United States and the World in general (Johanes, 2004). The s tudy will narrow down its research to the natural disasters that global warming has been causing in the West states of the country. This is due to the observed and recorded rise of the natural disasters that have been befitting this region of the country in the recent past. This is extremely related and associated with global warming by scientists who have carried out extensive studies on this topic (Mooney, 2007). The most productive regions in the Western part of the United States, including California, Idaho, Oregon, Washington, and Montana have been adversely affected by the outcome of global warming. Due to the natural disasters, the economic and social aspects of human beings are affected. The research tries to get the relationship between the increasing temperatures of the atmosphere due to greenhouse gases and the climatic menace of global warming (Weart, 2003). It will also be aiming at establishing the relationship between the global warming and the natural disasters, whic h have befitted these regions of the United States. Global warming has been found to be the major cause of natural disasters including the rising levels of the sea and ocean waters resulting into tsunamis, extensive melting of ice fields in the Greenland nations, extensive climatic changes in the increase of temperatures and reduction of rainfall in the African region. Moreover, global warming is the main cause of the many extensive wildfires, which have destroyed lots of vegetation and forests in the United States especially in the western States of Colorado and California (Mooney, 2007). Purpose Statement The purpose of this survey study will be to test the problem of the western United States increasing temperatures, which relates to past and future climate in the surrounding areas current climate. The independent variables will be defined as (i) increasing temperatures in the mountains are affecting snow melt, (ii) pronounced droughts are the effects of warmer temperatures in th e southwestern United States, and (iii) simulations of present and future climates performed with four regional climate models. The dependent variable will be defined as current climate. Statement of the Problem This study aims to prove the relations of global warming to the rising natural disasters in the western United States. It addresses the following questions in the study: 1. What is the relationship of global warming to changes in the climactic condition of the Western States? 2. What is the current temperature in the mountainous area of the western States? 3. How is the temperature in the mountains affect the melting of glaciers in Glacier National Park? 4. What is the

Discussion Board creminal justice Essay Example | Topics and Well Written Essays - 750 words

Discussion Board creminal justice - Essay Example (Burright) Nonetheless, in recent past the privatization of prisons and jails found the way back into the criminal justice, once again arousing a wave of controversy and debate. Over-crowded correctional facilities, decreasing revenues, increasing crime rates, public call for more prison sentences and longer criminals' incarceration are among the factors that forced the nation's prison system to once again consider the option of private contracting to provide privatization of prisons and jails. ... Considering all these benefits, by 1987, three States had approved legislation authorizing private businesses to operate the State correctional facilities. At present, there are a lot of states and counties that have prisons being operated by private companies. So while the legal aspects of government delegating its responsibility for the custody of an individual to private organizations was much discussed in the 1980s, today it is clear that "objections to prison privatization on constitutional delegation grounds have little force". (McDonald, p.6) It is interesting that with so many privately operated correctional institutions in the country, there is no any case law to define exactly how general process standards are applied to private jails and prisons. There is no special legislation defining the authority of private contractors regarding use of force, especially deadly force. Privately run facilities usually lack legal authority to respond to various critical situations, e.g. escape and other emergencies. There is a great need for legislation that would govern these practices. Without proper legal solution to this absence of the relevant law of jurisdiction, it is quite possible that private companies will have to face civil or criminal liability. Special legal questions arise when sending prisoners from a certain jurisdiction to another, privately operated one. Some jurisdictions rely on contracts, others - on intermediary governments when placing prisoners in private jails. There is no common ground and these inter-juris dictional issues also put a question mark on the sufficiency of legal regulation and authority. To address other reasons proponents of prisons privatization offer, one should mention that there is no strong evidence to support the

Arthropod pests Essay Example for Free

Arthropod pests Essay The concern that human society will be inevitably obsessed with death is a valid one. Although there may be people today who escape depressing thoughts of death, all will be distraught after reading only a few lines of the Lament for Ignacio Sanchez Mejias. This essay will analyze parts of the work by Federico Lorca and provide some basic interpretations and thoughts on the subject. Beginning with the first line of the lament, the reader is struck with an overwhelming sense of time—five in the afternoon. It fills the mind as the words continue. â€Å"It was exactly five in the afternoon. † Ignacio has obviously died. The time of day is noted, and the question arises immediately: why repeat the time â€Å"five in the afternoon† after every line (up to five times)! I think the point of repeating the time excessively is to pound a feeling of monotony that accompanies utter grief into the mind of the reader. Also, it provides a broad scope to help the reader understand how many hopelessly depressing things are going on at once. A possible answer, then, is that the lament needs synchronization in order to deliver the correct emotions that Lorca felt. For example, leaving out the repeated time, the first stanza becomes, â€Å"A boy brought the white sheet, A frail of lime ready prepared, The rest was death, and death alone. † In this version, the reader feels like three mundane, somewhat depressing things are happening in sequence as opposed to feeling a horrifying realization of the simultaneous events surrounding the loss of a close friend. Without the repetition it may still seem sad, but nowhere near as powerful as the original. Adding the repetition back in, one feels as though time has been stopped during a metaphorical symphony of pain from grief. As the horrible moment continues, Lorca adds additional imagery: â€Å"Groups of silence in the corners†¦ A coffin on wheels is his bed†¦ The room was iridescent with agony†¦ In the distance the gangrene now comes†¦ The wounds were burning like suns†¦ at five in the afternoon. At five in the afternoon. Ah, that fatal five in the afternoon! It was five by all the clocks! It was five in the shade of the afternoon! † It is no accident that we read of the time of day five times at the end of this section. Also, both of the first two stanzas contain five references to the time as well, almost suffocating us with the existence of the terrible hour. Lorca perfectly displays the effect of death on the human mind. Cluttered with the details most ignored in regular life, our brains (perhaps as a self-defense to keep us alive) go through an almost physical withdrawal when those near to us die. In conclusion, It is obvious that our lives revolve around death whether we like it or not. Death is the nemesis of survival, and survival is our primary goal in life as humans. Reproduction, social reform, religion, or anything else we live for (even hedonism) must manifest itself through survival of ourselves or others. Thus, as long as we survive, humans will always be obsessed with death.

Eulogy for Friend :: Eulogies Eulogy

Eulogy for Friend Georganna's admirers--and that's everyone who knew her--savor the mile we walked with her. Each of us has special incidents we want to recount. We have compiled a few of these memories that we believe best illustrate the unique personality of our dynamic friend. Georganna was always determined, sometimes outraged, but rarely sad. Enjoy these stories. As long as we have them in our hearts, we have George. At the Team Spirit Leadership Conference George roomed with Heather, Tatum and Erica. She was always the First one up--usually by 4:00a.m. BUT she was always the LAST one ready! On the French Trip to Louisiana George slept in those teal green, silk pajamas whiles everyone else slept in shorts or sweats! But that was George. She dressed up for school every day like she was going off to New York. Shawn always said George was in a time warp because he was wearing clothes from another generation! George was the "Debate Queen"--that's what everyone called her. On the bus trip to Louisiana George climbed over the seats to view her opinion on at least five different issues! She would never back down. When George started to go off about an issue during class or on the weekend, Ryan, Shawn, and all the guys would hiss (like the wind was blowing). Georganna would just roll her eyes at them and smile. Georganna loved to read. Everyone always teased her about those "smut" novels! She could read a different one every day. During Flag Core practice Georganna's freshman year, Katrina accidentally hit Georganna on the head with her flag--but Georganna really got upset and chased Katrina around the entire school with the flag pole! Georganna loved chocolate--and she'd get sooo hyper when she ate it! Taco Bell was also her favorite. She could be found there every weekend with different friends. Kenny Samples was bored one day and went through George's purse. He bit her drivers license and credit cards and actually left teeth marks on them. George often showed them to her friends and laughed about it. One night Tatum, Kristie, Daren, Micah, and George went on a yard-rolling spree. Amanda pulled into her driveway as they were rolling her yard. They were running off and George started picking up the rolls of toilet paper. She said, "We might can use them later!" She had also insisted on color coordinating the paper before it was bought! Eulogy for Friend :: Eulogies Eulogy Eulogy for Friend Georganna's admirers--and that's everyone who knew her--savor the mile we walked with her. Each of us has special incidents we want to recount. We have compiled a few of these memories that we believe best illustrate the unique personality of our dynamic friend. Georganna was always determined, sometimes outraged, but rarely sad. Enjoy these stories. As long as we have them in our hearts, we have George. At the Team Spirit Leadership Conference George roomed with Heather, Tatum and Erica. She was always the First one up--usually by 4:00a.m. BUT she was always the LAST one ready! On the French Trip to Louisiana George slept in those teal green, silk pajamas whiles everyone else slept in shorts or sweats! But that was George. She dressed up for school every day like she was going off to New York. Shawn always said George was in a time warp because he was wearing clothes from another generation! George was the "Debate Queen"--that's what everyone called her. On the bus trip to Louisiana George climbed over the seats to view her opinion on at least five different issues! She would never back down. When George started to go off about an issue during class or on the weekend, Ryan, Shawn, and all the guys would hiss (like the wind was blowing). Georganna would just roll her eyes at them and smile. Georganna loved to read. Everyone always teased her about those "smut" novels! She could read a different one every day. During Flag Core practice Georganna's freshman year, Katrina accidentally hit Georganna on the head with her flag--but Georganna really got upset and chased Katrina around the entire school with the flag pole! Georganna loved chocolate--and she'd get sooo hyper when she ate it! Taco Bell was also her favorite. She could be found there every weekend with different friends. Kenny Samples was bored one day and went through George's purse. He bit her drivers license and credit cards and actually left teeth marks on them. George often showed them to her friends and laughed about it. One night Tatum, Kristie, Daren, Micah, and George went on a yard-rolling spree. Amanda pulled into her driveway as they were rolling her yard. They were running off and George started picking up the rolls of toilet paper. She said, "We might can use them later!" She had also insisted on color coordinating the paper before it was bought!

Spectrophotometry

Spectrophotometry: is a device to measure the amount of light in the material used. this device consists of two parts: the first is the light source, and the second is the photometer . the work principle of this device : the liquid or material that we want to measure the elements inside is placed in a tub, this tube is then placed between the light source and the photometer . So that the amount of light passing through the sample is measured by photometer. when a photometer is exposed to light, it acquires or generates an electrical signal that changes with the amount of light absorbed by the liquid . this change in light absorption depends on the change in the concentration of the substance. the way work this device: this device it measures the absorption of light by liquid materials at different wavelengths, and thus can identify a number of unknown substances or calculate known concentrations of materials . Stepped flow Technique:is a rapid mixing device, to study the kinetics of quick chemical reactions in solutions . this device contains two reactants which are kept in separate reservoirs and are prevented from flowing freely . the interaction starts by installing the reactants in the device. these materials are then released to the mixing chamber, which mixes these interacting materials , the reaction is then monitored by observing the change in the absorption of the reaction solution . When the reaction progresses, it fills the â€Å"stop syringe† that expands until it reaches the point at which the interaction reaches a continuous flow , thus stopping flow or interaction sodium reacts strongly and quickly with water and produces a solution of sodium hydroxide and hydrogen gas, a colorless solution. During the reaction sodium can be heated and It may ignite and burn with an orange flame . Hydrogen gas released during the combustion process reacts with oxygen in the air . The resulting solution is basic because of the melting of sodium in the water. this interaction between sodium and water is an exothermic reaction. sodium reaction with water is the closest to explosion. Na +2 H2O ?2 NaOH + H2. this search used this interaction and because it is fast, it uses the stepped-flow techniques method to control it Rate=- (d[Na])/dt=-1/2 (d[H2O])/dt=1/2 (d[NaOH])/dt+(d[H2])/dt Spectrophotometry Spectrophotometry is a vary specific type of Spectroscopy which measures how much light is absorbed by measuring the intensity of the light beam that is not absorbed (transmittance).The word â€Å"Spectra† means the range of wavelength, â€Å"Photo† means light or photons and â€Å"Metry† is the measuring how much light a chemical substance absorbs which it calls the absorbance. But what we do is measure how much light of the original light beam gets through (transmittance). So, those are related to each other absorbance and percent transmittance mathematically.The basic way to works is the incident light which usually contain different kind of wavelength, for example when we see something have a red color that means the object is absorbs all colors' wavelength except red. It is helpful to know the color wheel because the color wheel will help you to understand or getting the idea of where in the visible spectrum you would except to see the best absorbance.The work principle of spectrophotometry in (Figure 1): Firstly, we have a light source typically white light contains all wavelengths. We want to collimate the light or make all the wavelengths parallel to one another so, the special collimator or lens can does that, then we pass the light beam through a prism to splits the light into its various wavelength so, for regular white light you get all the colors of the rainbow. Spectrophotometer does not just shine all that light at the sample, it shines a vary specific wavelength of light and we can choose that normally by moving a slit in the way of the one wavelength of light or color that we would like to shine through the sample. That particular color of light will then shine through the sample, some of it will be absorbed and some of it will be transmitted. (Io) is the incident light that is the first enters, and (It) is the amount of light that is transmitted through after some has been absorbed. The remaining light that gets through hits a photocell, photocell is a solid-state detector that picks up how much light, then it prints out on a digital display either absorbance how much was taken away or percent transmittance how much light go through and those two are related. Briefly,  you can determine the unknown concentration of the sample by using Beer-Lambert Law which states: there is a linear relationship between the absorbance and the concentration of a sample. Mathematical formula of Beer's Law is: A=?lcA  is the measure of absorbance.?  is the molar extinction coefficient or molar absorptivity.l  is the path length.-439528256528center842086600left221268Figure 100Figure 1c  is the concentration (which is required).There are special techniques for investigating fast reactions which have half-live less than a few secondsLet us take an example for the simplest fast reaction technique (the continuous flow method) which will be used to study the kinetics of the formation of the ferric thiocyanate complex FeSCN+22120900145742100 For the fast reaction between ferric and thiocyanate ions in an acid solution of constant pH, the observed behavior is consistent with the simple mechanism: center2191301Where kf is the bimolecular forward rate constant and kr is the unimolecular reverse rate constant. So, the rate law from this equation is:center27279960Recall that the equilibrium constant K is related to the rate constant by:15775923297435 Where the sign ? means the equilibrium (t=?) value:31439213903453641206384715300At any time (t), Using these relations, and then rewrite the equation in the form:1965852489141700To simplify the integration of this equation, we will choose the experimental conditions such that [Fe+3] ;; [SCN-]. This will allow us to assume that [Fe+3] is essentially constant during the reaction. The initial conditions are chosen so that [FeSCN+2]0= at t=0 we find:This an approximate solution which becomes exact only when [Fe+3] is constant. In real practice, [Fe+3]0 will be chosen to be ten times larger than [SCN-]0, so that [Fe+3] will be more by about 10 percent during the reaction.2803525690943500-569595690918400If a plot of ln](FeSCN+2)? – (FeSCN+2)[ versus t is linear, then the first order dependence on [SCN-] and [FeSCN+2] is confirmed. The rate dependence on [Fe+3] has been established as first order. -5779714625Schematic diagram of system for driving reactant solution.00Schematic diagram of system for driving reactant solution.452856889798Spectrophotometry setup00Spectrophotometry setupProcedure for an example of use Spectrophotometer technique in fast reaction: Firstly, turn on the spectrophotometer and leave it warm up before using. The wavelength setting should be 455 nm throughout the entire experiment. With both reagent stopcocks A and B and the vent stopcock V closed, slowly increase the gas pressure on the reagent solutions until Bourdon pressure gauge indicates about 500 Torr pressures above 1 atm. With the outlet stopcock C open, open and close the reagent stopcocks A and B several times to make sure that both solutions are flowing smoothly and to remove any air bubbles from the system. Use a beaker to catch the outflow from the capillary tube. Then set the capillary frame at the first fiducial mark which nearest to the mixing chamber, and carry out the three following steps:1- Open Stopcock A and allow the Fe+3 solution to flow for a sufficient time to remove from the capillary tube any solution containing FeSCN+2 species. Then close stopcock A and the outlet stopcock C.2- Open the outlet stopcock C then turn both stopcocks A and B to their fully open positions. Catch the outflow of solution from the capillary in a beaker until the flow becomes stable. Then quickly switch the outlet tube from the beaker to a volumetric flask and simultaneously start a timer. When It is full, stop the timer and record the time. Return the outlet tube to the beaker. Then carrying out the above flow rate measurement, you should determine the absorbance A of the reaction mixture and record that value together with the distance x from the mixing chamber. Work quickly to avoid any interference of the reagent solution.3- When both the flow and absorbance measurements are complete, close the outlet stopcock C and then close both stopcock A and B. This is a crucial step in the procedure. If A and B are left open, solution may siphon from one carboy to the other. After a few minutes, determine the absorbance again to obtain the infinite time value. Verify that this value does not change after one more minute. For the next run, move the capillary support frame so as to line up the second fiducial mark and repeat the first and third steps at this this new distance setting, be careful in moving the capillary support frame.Make two runs at each of the six or seven positions along the capillary tube. Use special care in making the absorbance readings at large values of x. If time permits, you should also take data at a different driving pressure. Either increase or decrease the gas pressure depending on weather you need more data at low percent reaction or at high, but it may not be safe to exceed about 700 torr overpressures.In this experiment, more of solution A will be used up than solution B if the Fe+3 solution is always used in the first step to make the zero adjustment of the spectrophotometer at each distance setting. The resulting change in the liquid level for A relative to that for solution B may change the relative flow rates of these solutions. This can be avoided by alternating the use of solution A and B for making the zero adjustments.References:1- Physical chemistry by  Gilbert William Castellan.2- msu.edu.3- Wiley online library. 4- UKessay.5- AliHayek.com Spectrophotometry 5448300-52387500-523875-53340000 Kinetics Chemistry Student Name:Saba Ahmad Bin Humaid Supervisor:Dr. Alia Abdulaziz Alfi Group Number: 41438-1439 Spectrophotometry is a technique which can be used for identifying reactants' concentrations.Spectrophotometry is an absorbance device which can measures the fraction of the incident light transmitted through a solution. More clearly, it is used to measure the amount of light that passes through particles of the sample and by differentiation of the initial intensity of light reaching the sample, it indirectly measures the amount of light absorbed by that sample. Spectrophotometers are made to transmit light of narrow wavelength ranges. A certain compound will not absorb all wavelengths evenly that's why things have different colours. Some compounds absorb only wavelengths outside of the visible light spectrum and that's why there are colourless solutions such as water. Because different compounds absorb light at different wavelengths, a spectrophotometer can be used to differentiate compounds by analyzing the type of wavelengths absorbed by a given sample. In addition of that, the amount of light absorbed is directly proportional to the concentration of absorbing compounds in that sample, so a spectrophotometer can also be used to determine concentrations of compounds in solution.To studying a compound in solution by spectrophotometry, you put it in a sample holder called a cuvette and place it in the spectrophotometer. Light of a specific wavelength passes through the solution inside the cuvette and the amount of light transmitted or absorbed by the solution is measured by a light meter. While a spectrophotometer can exhibit measurements as either transmittance or absorbance, in biological applications we are usually interested in the absorbance of a given sample. Because other compounds in a solution (or the solvent itself) may absorb the same wavelengths as the compound being analysed, we compare the absorbance of our test solution to a reference blank. The reference blank should contain everything found in the sample solution except the substance you are trying to analyse or measure.Briefly,-5143507591425003467100758190000  you can determine the unknown concentration of the sample by using Beer Lambert Law which states: there is a linear relationship between the absorbance and the concentration of a sample. Mathematical formula of Beer's Law is: A=?lcWhere:A  is the measure of absorbance.?  is the molar extinction coefficient or molar absorptivity.l  is the path length.c  is the concentration (which is required).There are special techniques for investigating fast reactions which have half-live less than a few secondsLet us take an example for the simplest fast reaction technique (the continuous flow method) which will be used to study the kinetics of the formation of the ferric thiocyanate complex FeSCN+22120900145742100 For the fast reaction between ferric and thiocyanate ions in an acid solution of constant pH, the observed behavior is consistent with the simple mechanism: center2191301Where kf is the bimolecular forward rate constant and kr is the unimolecular reverse rate constant. So, the rate law from this equation is:center27279960 Recall that the equilibrium constant K is related to the rate constant by:15775923297435Where the sign ? means the equilibrium (t=?) value:31439213903453641206384715300At any time (t), Using these relations, and then rewrite the equation in the form:1965852489141700To simplify the integration of this equation, we will choose the experimental conditions such that [Fe+3] ;; [SCN-]. This will allow us to assume that [Fe+3] is essentially constant during the reaction. The initial conditions are chosen so that [FeSCN+2]0= at t=0 we find:This an approximate solution which becomes exact only when [Fe+3] is constant. In real practice, [Fe+3]0 will be chosen to be ten times larger than [SCN-]0, so that [Fe+3] will be more by about 10 percent during the reaction.2803525690943500-569595690918400If a plot of ln](FeSCN+2)? – (FeSCN+2)[ versus t is linear, then the first order dependence on [SCN-] and [FeSCN+2] is confirmed. The rate dependence on [Fe+3] has been established as first order. -5779714625Schematic diagram of system for driving reactant solution.00Schematic diagram of system for driving reactant solution.452856889798Spectrophotometry setup00Spectrophotometry setupProcedure for an example of use Spectrophotometer technique in fast reaction: Firstly, turn on the spectrophotometer and leave it warm up before using. The wavelength setting should be 455 nm throughout the entire experiment. With both reagent stopcocks A and B and the vent stopcock V closed, slowly increase the gas pressure on the reagent solutions until Bourdon pressure gauge indicates about 500 Torr pressures above 1 atm. With the outlet stopcock C open, open and close the reagent stopcocks A and B several times to make sure that both solutions are flowing smoothly and to remove any air bubbles from the system. Use a beaker to catch the outflow from the capillary tube. Then set the capillary frame at the first fiducial mark which nearest to the mixing chamber, and carry out the three following steps:1- Open Stopcock A and allow the Fe+3 solution to flow for a sufficient time to remove from the capillary tube any solution containing FeSCN+2 species. Then close stopcock A and the outlet stopcock C.2- Open the outlet stopcock C then turn both stopcocks A and B to their fully open positions. Catch the outflow of solution from the capillary in a beaker until the flow becomes stable. Then quickly switch the outlet tube from the beaker to a volumetric flask and simultaneously start a timer. When It is full, stop the timer and record the time. Return the outlet tube to the beaker. Then carrying out the above flow rate measurement, you should determine the absorbance A of the reaction mixture and record that value together with the distance x from the mixing chamber. Work quickly to avoid any interference of the reagent solution. 3- When both the flow and absorbance measurements are complete, close the outlet stopcock C and then close both stopcock A and B. This is a crucial step in the procedure. If A and B are left open, solution may siphon from one carboy to the other. After a few minutes, determine the absorbance again to obtain the infinite time value. Verify that this value does not change after one more minute.For the next run, move the capillary support frame so as to line up the second fiducial mark and repeat the first and third steps at this this new distance setting, be careful in moving the capillary support frame.Make two runs at each of the six or seven positions along the capillary tube. Use special care in making the absorbance readings at large values of x. If time permits, you should also take data at a different driving pressure. Either increase or decrease the gas pressure depending on weather you need more data at low percent reaction or at high, but it may not be safe to exceed about 700 torr overpressures.In this experiment, more of solution A will be used up than solution B if the Fe+3 solution is always used in the first step to make the zero adjustment of the spectrophotometer at each distance setting. The resulting change in the liquid level for A relative to that for solution B may change the relative flow rates of these solutions. This can be avoided by alternating the use of solution A and B for making the zero adjustments.References:1- Physical chemistry by  Gilbert William Castellan.2- msu.edu.3- Wiley online library. 4- UKessay.5- AliHayek.com