...ASCE. For personal use only; all rights reserved. By Shaoying Qi, 1 Samer S. Adham, 2 Vernon L. Snoeyink, 3 and Ben W. Lykins Jr. 4 ABSTRACT: A procedure was developed to predict the removal of trace organic compounds from natural water by powdered activated carbon (PAC) adsorption systems, which function as a batch reactor or a continuous stirred tank reactor (CSTR). The procedure uses the equivalent background compound method coupled with the ideal adsorbed solution theory to quantify the competition between trace organicsand background organic matter in water, and uses the pseudo single-solute homogeneous surface diffusion model to describe the adsorption kinetics of the target compound under the influence of the background organic matter. The parameters required by the model as input data can be independently determined from adsorption isotherms and a set of batch kinetic test data. Good agreement between predicted and actual performance was found for adsorption of atrazine from Central Illinois ground water at different initial concentrations and different carbon doses using a batch reactor and two CSTRs, one of which was a PAC/ ultrafiltration system. INTRODUCTION Strict drinking-water standards have been p r o p o s e d for many organic compounds [Federal Register 1987, 52(No. 130; July 8), 1989, 54(No. 97; May 22); Clark 1989], and the water industry needs to have an effective, economical way to meet the standards. P o w d e r e d activated carbon...
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...Abstract There is a growing importance for the studies of frequency stability and control of power system with increasing levels of wind power penetration, especially in United States with a goal of 20% or more by 2030. The increasing penetration of wind in to existing synchronous based generation capacity requires the modifications in the procedures of grid frequency control as wind turbine units fail to provide inertial support and primary control reserves during the initial and later stages of frequency events respectively. Therefore, it is necessary for the wind turbines to emulate the response of current synchronous based generation capacity so as to make the power system reliable. This type of response can be introduced by control schemes developed. This report provides a literature review of the frequency control basics and controller schemes used. And also it provides an overview of the basic concepts related to the effects of wind generation on frequency behavior of the power system network. Introduction Frequency stability and control very much dependent on active power balancing is a major research topic concerned with grid integration of large wind farms. The instability of frequency occurs when power system fails to maintain it within particular limits under normal conditions. Active power imbalance indicates the variations in frequency and consequently the constancy of frequency represents the quality of power supply. Such an imbalance can be due...
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...CHAPTER 14 CHEMICAL KINETICS PRACTICE EXAMPLES 1A (E) The rate of consumption for a reactant is expressed as the negative of the change in molarity divided by the time interval. The rate of reaction is expressed as the rate of consumption of a reactant or production of a product divided by its stoichiometric coefficient. A 0.3187 M 0.3629 M 1min rate of consumption of A = = = 8.93 105 M s 1 t 8.25 min 60 s rate of reaction = rate of consumption of A2 = 8.93 105 M s 1 4.46 105 M s 1 2 1B (E) We use the rate of reaction of A to determine the rate of formation of B, noting from the balanced equation that 3 moles of B form (+3 moles B) when 2 moles of A react (–2 moles A). (Recall that “M” means “moles per liter.”) 0.5522 M A 0.5684 M A 3moles B rate of B formation= 1.62 104 M s 1 60s 2 moles A 2.50 min 1min 2A (M) (a) The 2400-s tangent line intersects the 1200-s vertical line at 0.75 M and reaches 0 M at 3500 s. The slope of that tangent line is thus 0 M 0.75 M slope = = 3.3 104 M s 1 = instantaneous rate of reaction 3500 s 1200 s The instantaneous rate of reaction = 3.3 104 M s 1 . (b) At 2400 s, H 2 O 2 = 0.39 M. At 2450 s, H 2 O 2 = 0.39 M + rate t At 2450 s, H 2 O 2 = 0.39 M + 3.3 10 4 mol H 2 O 2 L1s 1 50s = 0.39 M 0.017 M = 0.37 M 2B (M) With only the data of Table 14.2 we can use only the reaction rate during the first...
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... Bujumbura, Burundi; des Sciences et Gestion de l’Environnement, Unité ‘Assainissement et Environnement’, Université de Liège, Arlon, Belgium (Received 12 March 2012; final version received 26 August 2012 ) The present study was undertaken to develop a simple and practical model for anaerobic digestion, encompassing sulphate reduction and sulphur oxidation, in a waste stabilization pond. The basic microbiological phases of the model consisted of four processes, namely acidogenesis, methanogenesis, sulphate reduction and sulphur oxidation. It also incorporated multiple reaction stoichiometry and substrate utilization kinetics. The study also aimed to investigate the mutual interaction between sulphate-reducing bacteria (SRB) and photosynthetic sulphur bacteria (PSB) in an anaerobic sludge consortia using batch reactors. The results revealed that for an initial concentration of sulphate ranging between 250 and 2800 mg.l−1 , SRB activity ranged between 20 and 190 mgSO2− reduced . The gVSS−1 .d−1 and PSB activity varied between 60 and 4 320 mgSO2− produced .gVSS−1 .d−1 , and PSB activity was noted to be twice as high as that of SRB. PSB can, therefore, 4 be used effectively in the fight against odors. The most important environmental factors affecting the sulphur cycle in the waste stabilization pond were likely to be the availability of sulphate and light for SRB and PSB, respectively. Keywords: modelling; sulphate-reducing bacteria; photosynthetic sulphur bacteria; stoichiometry;...
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...English (epdf) Article in xml format Article references How to cite this article Automatic translation Send this article by e-mail Indicators Have no cited articlesCited by SciELO Access statistics Related links Share Share on deliciousShare on googleShare on twitterShare on diggShare on citeulikeMore Sharing ServicesMore More Sharing ServicesMore Permalink Brazilian Journal of Chemical Engineering On-line version ISSN 0104-6632 Braz. J. Chem. Eng. vol.29 no.3 São Paulo July/Sept. 2012 http://dx.doi.org/10.1590/S0104-66322012000300003 BIOPROCESS ENGINEERING Study on fermentation conditions of palm juice vinegar by response surface methodology and development of a kinetic model S. Ghosh; R. Chakraborty; G. Chatterjee; U. Raychaudhuri* Centre for Medicinal Food and Applied Nutrition, Department of Food Technology and Biochemical Engineering, Fax: 91-033-24146822, Jadavpur University, Kolkata, 700032, India. E-mail: utpal31@hotmail.com ABSTRACT Natural vinegar is one of the fermented products which has some potentiality with respect to a nutraceutical standpoint. The present study is an optimization of the fermentation conditions for palm juice vinegar production from palm juice (Borassus flabellifer) wine, this biochemical process being aided by Acetobacter aceti (NCIM 2251). The physical parameters of the fermentation conditions such as temperature, pH, and time...
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...Introduction: In this experiment, the rate law and rate constant for a reaction of oxalic acid with permanganate were determined. Every chemical reaction ranges from hours to femtoseconds to occur. The rate of a chemical reaction can be determined by assessing the change in either the reactant or product in a given time or point (Connors, 1990). It is important to take account of the stoichiometric ratios of each component, regardless as to which compound is chosen to determine the rate. The study of the rates of chemical reactions is called Chemical Kinetics (Soustelle, 2011). The following is an example of a generic chemical reaction: aA + bB → cC + dD The rate of the reaction can be expressed as a function of each reactant and each product: Rate = -1a∆A∆t= -1b∆B∆t= +1c∆C∆t= +1d∆D∆t For each reaction, the concentration is decreasing as the reaction occurs; therefore representing the rate as a positive value and a negative sign in the rate definition is used. The concentration of the products is conversely increasing as the reaction proceeds; therefore changing in concentration is positive (Connors, 1990). The reaction rate can be measured by accurately measuring the change in concentration of one of the reaction species over time. This experiment utilized a visual change in color of one of the reactants used; however, since visual indications can be subjective and it is important to perform the experiment multiple times. Also, since the color change would indicate that...
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...Michaelis-Menten Kinetics: The Enzyme-Catalyzed Hydrolysis of Sucrose1 Background Of the numerous chemical reactions whose kinetics have been studied, some of the most interesting and complex are those which take place in living organisms. These reactions, when studied under non-biological conditions (lack of organisms and their various biomolecules), are often exceptionally slow: often hours or days, and sometimes even years are required before equilibrium is reached. Yet life requires seconds or even fractions of seconds to produce the same results, and it does this through the use of biological catalysts called enzymes. Enzymes are proteins with special clefts or pockets in their structures in which the reactions occur: the tremendous advantage that enzymes have is that these pockets, by nature of their shape and chemical environment, force the reactants to form transition states much lower in energy than the transitions states the reactants would form under other circumstances, say in solution. Thus, life can subsist at a reasonable pace and it does not take us a week to walk across a room or digest an apple. Of the many kinetic models for enzymes currently used, the first (and simplest) developed is the Michaelis-Menten Model, developed in 1913 by Leonor Michaelis and Maud Menten, which is still quite useful today. One of its early triumphs was the successful explanation of the kinetics of sucrase, or β-fructofuranidase, an enzyme found in yeast which cleaves...
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...Determination of the Reaction Rate of Mg and HCl Alex Skartvedt Alex Skartvedt, Melanie Ho, Christina Olson, Thor Swerdykiak November 11, 2015 Fall 2015 Semester Abstract: The experimental rate law of the reaction: 2HCl(aq)+Mg(s)→MgCl2(aq)+H2(g) is being determined because kinetics play a large role in the reactions happening in everyday life. The rate law, k value will be obtained in the experiment. To obtain the information a pressure probe was connected to an Erlenmeyer flask in order to record the rate of the reaction of magnesium ribbon and hydrochloric acid. The order of HCl and Mg were then determined using the information found in from the reaction. The order in HCl and Mg were found to be less than the expected...
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...‘Fluid’ is defined as a substance that can flow. There are two types of fluids, gases and liquids. A Steady flow process occurs when the state of fluid conditions at any point in the control volume remain constant with respect to time. Specifically, the mass flow rate entering the system is equal to the mass flow rate exiting the system. Conversely, non-uniform flow process is when the velocity varies at any instant. The common systems which involve steady flow processes are open system turbines, compressors, pumps etc. [1] (W.BOLTON, 1990) Background Theory Steady flow energy equation The development of the Steady Flow Energy Equation of fluid is derived from the principle of conservation of energy which state that: For any mass system, the net energy supplied to the system equals the increase of energy of the system plus the energy leaving the system. Therefore, if is the increase of energy of the system, is the energy supplied to the system and the energy leaving the system. Therefore, the energy balance for the system is considered. The energy of a mass of fluid contains the forms as followed: 1. Internal energy due to the activity of the molecules of the fluid forming the mass; 2. Kinetic energy due to the velocity of the mass of fluid itself; 3. Potential energy due to the mass of fluid being at a height above the datum level and acted upon by gravity. [2] As steady flow operation concludes that no energy may be stored within the systems, therefore...
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...and activated carbon obtained from hazelnut shell. It also aimed to determine the effect of ZnCl2 in the activation process. The hazelnut was pyrolyzed at 250 and 700 °C. For determining the capture speed of the adsorbents, the pseudo-first- and second-order kinetic studies were performed. The Freundlich and Langmuir isotherm models were used to determine adsorption equilibrium. The surface characterization of hazelnut shell and activated carbon was determined by Brunauer-Emmett-Teller (BET) analysis and FTIR spectrum. Pb+2 adsorption capacity of obtaining activated carbon was determined by ICP-OES analysis. The raw hazelnut shell’s BET surface area is 5.92 m2/g and the surface area of activated carbons which is pyrolyzed at 250 and 700 °C were determined (270.2 and 686.7 m2/g, respectively. The surface area of hazelnut shell, which pyrolyzed at 700 °C after being activated with ZnCl2, was determined to be 736.49 m2/g. Results show that physical adsorption process is dominant for the activated carbon pyrolysis at 700 °C but the chemical adsorption is dominant for the activated carbon pyrolysis at lower degrees and for raw hazelnut shell. Keywords Activated carbon . Heavy metals . Lead(II) . Kinetic . Isotherm . Hazelnut Responsible editor: Philippe Garrigues A. Şencan (*) : M. Karaboyacı Department of Chemical Engineering, Süleyman...
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...form 1 October 2011 Accepted 3 October 2011 Available online xxxx Keywords: Tumor growth Gompertz model Non-linear observer Non-linear systems discretization abstract Cancer represents one of the most challenging issues for the biomedical research, due its large impact on the public health state. For this reason, many mathematical methods have been proposed to forecast the time evolution of cancer size and invasion. In this paper, we study how to apply the Gompertz’s model to describe the growth of an avascular tumor in a realistic setting. To this aim, we introduce mathematical techniques to discretize the model, an important requirement when discrete-time measurements are available. Additionally, we describe observed-based techniques, borrowed from the field of automation theory, as a tool to estimate the model unknown parameters. This identification approach is a promising alternative to traditional statistical methods, and it can be easily extended to other models of cancer growth as well as to the evaluation of not measurable variables, on the basis of the available measurements. We show an application of this method to the analysis of solid tumor growth and parameters estimation in presence of a...
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...to Professor Christina Barazona College of Science and Mathematics - Department of Biological Sciences Mindanao State University – Iligan Institute of Technology Andres Bonifacio Avenue, Tibanga, 9200 Iligan City, Philippines By Janna R. Andalan August 2013 ABSTRACT The Experiment conducted involves diffusion. The point of this experiment was to know the characteristics of diffusion and to formulate hypothesis based on diffusion. It has also a purpose to see whether the diffusion is dependent on distance, rate and molecular weight of the substance. The estimation of distance is predicted by getting the average of the substance. Rate is predicted by subtracting the final diameter to initial diameter and dividing it by time. It is determined that there are three things which influence the movement of molecules such as kinetic energy, nature of the environment and size of the molecules. By this, we know which dye diffused at the fastest rate by measuring the diameter of the colored area immediately after adding the substance to the agar plate. After one hour of measuring the methylene blue by 15 minutes interval, the substance moved immediately in 0min until 45minutes, the remaining minutes remains the same. While on the potassium permanganate, the substance moved from 0minutes to 1hour. These happened because they had different molecular weight and also the size of the substance that we put on the agar plate. It is expected that once a substance place into an...
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...biological catalysts. An enzyme can act to speed up or regulate the rate of the reaction, in order to maintain an efficient rate of biological reactions. Enzymes, whilst having an important role in the reaction of many chemicals within the body, are not consumed in the reaction, and so are able to catalyze many reactions in their life cycle. Enzymes are able to reduce the activation energy of the reaction; the energy required to break bonds between the reactants, and form new bonds in the products, which allows more product to be formed. (Marieb and Hoehn, 2010, pp.51-53). Enzyme activity is affected by changes in the pH of their solution. For each individual enzyme, there is a corresponding pH at which, that particular enzyme’s activity will be at it’s maximum. This is known as the optimum pH. If the pH of the solution is getting closer to it’s optimum pH for that particular enzyme, then the activity of the enzyme, and therefore it’s rate of reaction, will increase. At extremes of pH (either extremely acidic or basic) enzymes tend to become denatured; a state in which they lose all of their biological activity. (Worthington Biochemical Corporation, 2011). Temperature has the ability to increase the reaction rate of chemical reactions, by increasing the kinetic energy of the molecules themselves. By increasing the kinetic energy of the molecules, there will be a greater proportion of molecules with enough kinetic energy to overcome the activation energy, and therefore form...
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...This article was downloaded by: [Universite de Lorraine] On: 10 February 2012, At: 06:13 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK Journal of Environmental Science and Health, Part A: Toxic/Hazardous Substances and Environmental Engineering Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/lesa20 Respirometric assessment of substrate binding by antibiotics in peptone biodegradation Ilke Pala Ozkok , Tugce Katipoglu Yazan , Emine Ubay Cokgor , Guclu Insel , Ilhan Talinli & Derin Orhon a a a b a a a a Environmental Engineering Department, Faculty of Civil Engineering, Istanbul Technical University, Maslak, Istanbul, Turkey b Turkish Academy of Sciences, Piyade Sokak, Cankaya, Ankara, Turkey Available online: 26 Oct 2011 To cite this article: Ilke Pala Ozkok, Tugce Katipoglu Yazan, Emine Ubay Cokgor, Guclu Insel, Ilhan Talinli & Derin Orhon (2011): Respirometric assessment of substrate binding by antibiotics in peptone biodegradation, Journal of Environmental Science and Health, Part A: Toxic/Hazardous Substances and Environmental Engineering, 46:13, 1588-1597 To link to this article: http://dx.doi.org/10.1080/10934529.2011.609442 PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions This article...
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...To determine the kinetics of the acid-catalyzed reaction of bromine and acetone via initial rate measurements and isolation method in order to approach the reaction mechanism. Data and discussion: The initial reaction of the production of brominated acetone can be written as: CH3COCH3 (aq)+ Br2 (aq) ---→CH3COCH2Br(aq) + Br– (aq) + H+ (aq) Data table Trial | Saturated Br2 solution (mL) | Acetone(mL) | 1.00 M HCl(mL) | Initial rate(abs/min) | [Ac](M) | [HCl](M) | Mole/L Br2 reacting per min per liter | Rate constant(M-1 min-1) | 1 | 3 | 5 | 10 | 0.0060 | 0.681 | 0.1 | 1.11 E-4 | 1.72 E-3 | 2 | 6 | 5 | 10 | 0.0060 | 0.681 | 0.1 | 1.17 E-4 | 1.72 E-3 | 3 | 9 | 5 | 10 | 0.0120 | 0.681 | 0.1 | 1.59 E-4 | 2.33 E-3 | 4 | 9 | 5 | 5 | 0.0120 | 0.681 | 0.05 | 1.60 E-4 | 2.33 E-3 | 5 | 9 | 5 | 20 | 0.0240 | 0.681 | 0.2 | 3.01 E-4 | 4.57 E-3 | 6 | 9 | 10 | 20 | 0.0480 | 1.362 | 0.2 | 6.23 E-4 | 1.10 E-3 | 7 | 9 | 20 | 20 | 0.0900 | 2.742 | 0.2 | 1.79 E-4 | 3.22 E-3 | The concentration of the saturated bromine solution was determined by diluting and measuring the absorbance of the solution at 450 nm .Distilled water was used as blank. The Beer’s law was then used to determine the concentration of bromine solution. Abs =ЄCl Where, Abs=0.288 and l= 1 cm and Є is the extinction coefficient or molar absorption coefficient = 100 (M-1 cm-1). So concentration of bromine solution was calculated using 1:100 dilution. To determine the initial rate, Abs vs. time (second)...
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