ENZYPLOTW: A USEFUL TOOL TO CALCULATE ENZYME KINETIC PARAMETERS
Directory of Open Access Journals (Sweden)
F.A Leone
2006-07-01
Full Text Available Assays of enzyme activity are among the most frequently employed procedures in biochemistry. They are used to estimate the amount of a given enzyme in a cell or tissue, to quantify kinetic parameters or to investigate a catalytic mechanism. The purpose of enzyme kinetics obtained under steady-state conditions is to estimate KM and VM values by fitting initial rate (v and substrate concentration (S values to the Michaelis-Menten equation, permitting a convenient graphical representation and an accurate estimation of KM and VM. However, there is no ideal assay for any particular enzyme and, since the assay of enzyme activity is essentially a kinetic measurement, various pitfalls await the unwary investigator. Despite difficulties consequent to intrinsic enzyme properties, kinetic parameters can be estimated accurately when steady-state conditions (<10% variation in substrate concentration during activity assay and initial rate measurements (catalytic enzyme concentration are guaranteed.EnzyplotW is an application developed for use on any Intel-based computer running Windows 98 or later, and uses a non-linear regression method to fit steady-state kinetic data for Michaelian enzymes. EnzyplotW can be employed not only for educational purposes but also in routine laboratory work, and includes three important features: teaching students how to obtain and recognize sound data for the best estimation of kinetic parameter values; aid the investigator at the bench in gauging the limitations of the various equivalent plots of the Michaelis-Menten equation used to estimate KM and VM; and allow the student to manipulate the mathematical formula of the corresponding plot to comprehend the qualitative and quantitative issues that govern the relationship between substrate
Directory of Open Access Journals (Sweden)
Pedro L. Valencia
2017-04-01
Full Text Available We provide initial rate data from enzymatic reaction experiments and tis processing to estimate the kinetic parameters from the substrate uncompetitive inhibition equation using the median method published by Eisenthal and Cornish-Bowden (Cornish-Bowden and Eisenthal, 1974; Eisenthal and Cornish-Bowden, 1974. The method was denominated the direct linear plot and consists in the calculation of the median from a dataset of kinetic parameters Vmax and Km from the Michaelis–Menten equation. In this opportunity we present the procedure to applicate the direct linear plot to the substrate uncompetitive inhibition equation; a three-parameter equation. The median method is characterized for its robustness and its insensibility to outlier. The calculations are presented in an Excel datasheet and a computational algorithm was developed in the free software Python. The kinetic parameters of the substrate uncompetitive inhibition equation Vmax, Km and Ks were calculated using three experimental points from the dataset formed by 13 experimental points. All the 286 combinations were calculated. The dataset of kinetic parameters resulting from this combinatorial was used to calculate the median which corresponds to the statistic estimator of the real kinetic parameters. A comparative statistical analyses between the median method and the least squares was published in Valencia et al. [3].
Niu, Sheng-Li; Huo, Meng-Jia; Lu, Chun-Mei; Liu, Meng-Qi; Li, Hui
2014-04-01
The catalytic capacity of dolomite in transesterification was investigated and the kinetic parameters were calculated. The activated dolomites as transesterification catalyst were characterized by X-ray diffraction, nitrogen adsorption and desorption and Hammett indicator method, where the original dolomite was analyzed by thermogravimetric and X-ray fluorescence in advance. Its potential catalytic capacity was validated from aspects of the activated temperature and the reused property, where the reliability of the experimental system was also examined. Then, influences of the catalyst added amount, the mole ratio of methanol to oil, the transesterification temperature and the transesterification time on the catalytic capacity were investigated. Finally, kinetic parameters of the transesterification catalyzed by the activated dolomite were calculated. Copyright © 2014 Elsevier Ltd. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Ince, M. [Gebze Institute of Technology, Department of Environmental Engineering, Gebze 41400, Kocaeli (Turkey); Yildiz, F. [Yildiz Technical University, Department of Electrical Engineering, Besiktas 34349, Istanbul (Turkey); Engin, G. Onkal [Gebze Institute of Technology, Department of Environmental Engineering, Gebze 41400, Kocaeli (Turkey)], E-mail: guleda@gyte.edu.tr; Engin, S.N. [Yildiz Technical University, Department of Electrical Engineering, Besiktas 34349, Istanbul (Turkey); Keskinler, B. [Gebze Institute of Technology, Department of Environmental Engineering, Gebze 41400, Kocaeli (Turkey)
2008-05-30
A novel circulating jet loop bioreactor adapted for organic matter oxidation has been designed and constructed. In this study, the input was leachate samples collected from Kemerburgaz Odayeri waste landfill site located on the European side of Istanbul. Controlling the jet loop bioreactor to realize high rates of purification depends on maintaining the appropriate loadings and operating conditions. This requires collecting various system data to estimate the dynamics of the system satisfactorily with the aim of keeping certain parameters within the specified range. The differential transform method (DTM) based solution of the state equations reveals the current state of the process so that any deviation in the system parameters can be immediately detected and regulated accordingly. The respirometric method for kinetic parameter calculations for biodegradation has been used for some time. In many studies, the respirometer was designed separately, usually in bench-scale. However, when a separate respirometer is used, the scale effect and parameters that affect the hydrodynamic structure of the system should be taken into consideration. In this study, therefore, the jet loop reactor itself was used as a respirometer. Thus, the kinetic parameters found reflecting the characteristics of microorganisms used for biodegradation would be more realistic. If the main reactor, here the jet loop reactor, would be used as the respirometer, the kinetic parameter changes can easily be monitored in the long run. Using the bioreactor as a respirometer, the most important kinetic parameters, K{sub s}, k{sub d} and {mu}{sub max} were found to be 11,000 mg L{sup -1}, 0.019 day{sup -1}, and 0.21 day{sup -1}, respectively. The stoichiometric coefficient, Y, was found to be 0.28 gr gr{sup -1} for the present system.
Ince, M; Yildiz, F; Engin, G Onkal; Engin, S N; Keskinler, B
2008-05-30
A novel circulating jet loop bioreactor adapted for organic matter oxidation has been designed and constructed. In this study, the input was leachate samples collected from Kemerburgaz Odayeri waste landfill site located on the European side of Istanbul. Controlling the jet loop bioreactor to realize high rates of purification depends on maintaining the appropriate loadings and operating conditions. This requires collecting various system data to estimate the dynamics of the system satisfactorily with the aim of keeping certain parameters within the specified range. The differential transform method (DTM) based solution of the state equations reveals the current state of the process so that any deviation in the system parameters can be immediately detected and regulated accordingly. The respirometric method for kinetic parameter calculations for biodegradation has been used for some time. In many studies, the respirometer was designed separately, usually in bench-scale. However, when a separate respirometer is used, the scale effect and parameters that affect the hydrodynamic structure of the system should be taken into consideration. In this study, therefore, the jet loop reactor itself was used as a respirometer. Thus, the kinetic parameters found reflecting the characteristics of microorganisms used for biodegradation would be more realistic. If the main reactor, here the jet loop reactor, would be used as the respirometer, the kinetic parameter changes can easily be monitored in the long run. Using the bioreactor as a respirometer, the most important kinetic parameters, Ks, kd and micromax were found to be 11,000 mg L(-1), 0.019 day(-1), and 0.21 day(-1), respectively. The stoichiometric coefficient, Y, was found to be 0.28 gr gr(-1) for the present system.
Calculation of LWR kinetic parameter β{sub eff}. validation on the mistral experiments
Energy Technology Data Exchange (ETDEWEB)
Santamarina, Alain; Erradi, Lahoussine, E-mail: alain.santamarina@cea.fr [CEA, DEN, SPRC, Saint-Paul-lez-Durance (France)
2011-07-01
This work presents the analysis of the MISTRAL experiments on the determination of the effective delayed neutron fraction β{sub eff} for UOX and MOX Light Water Reactor cores using the APOLLO2.8 code and JEFF-3.1.1 nuclear data library. The objective is to check if the new 8 time groups data in JEFF3 library (instead of the classical 6 groups) allows reducing the Calculation - Experiment discrepancy observed when using ENDF/B-VII or the previous JEF-2 library. Our analysis has shown that the C/E bias is reduced from +2.8% to +0.8% ± 1.6% for the UOX cores and from +0.8% to +0.2% ± 1.6% for the MOX cores. (author)
Energy Technology Data Exchange (ETDEWEB)
Pal, Partha P., E-mail: phys.ppal@gmail.com; Manam, J.
2014-01-15
Lithium co-doped ZnO:Eu{sup 3+} and ZnO:Tb{sup 3+} nanophosphors were prepared by co-precipitation method and the effect of Li{sup +} co-doping was systematically studied by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV-Vis-NIR reflectance, Photoluminescence (PL) spectroscopy and Thermoluminescence (TL) studies. XRD pattern shows typical peak pattern for hexagonal wurtzite structure and matches JCPDS card no. 79-0206. A shift of the (1 0 1) peak towards the lower angle in Li{sup +} co-doped samples can be observed showing the increase of lattice constant for the incorporation of Li{sup +} ions in the lattice sites. The present samples are found to be consisting of nanorods of diameter 60–90 nm as revealed by the SEM image. The FTIR pattern shows the enhancement of peak intensity for the ZnO in the Li{sup +} co-doped samples. The diffuse reflectance study shows red shift of the absorption edges in Li{sup +} co-doped ZnO:Eu{sup 3+} and Li{sup +} co-doped ZnO:Tb{sup 3+}. PL study reveals that a very small amount of Li{sup +} is very effective for charge compensation and for producing lattice defect to enhance the rare-earth related emissions, whereas a little excess of Li{sup +} brings oxygen vacancies, which leads to luminescence quenching. The prominent peaks of the TL glow curves of Li{sup +} co-doped ZnO:RE{sup 3+} samples are found to be increased than that of ordinary ZnO:RE{sup 3+} samples. The peaks are also shifted towards the lower temperature from the peaks of ZnO:RE{sup 3+} due to the Li{sup +} co-doping. The TL glow curves of the Li{sup +} co-doped ZnO:RE{sup 3+} samples are found to obey first order kinetics. The samples are found to be very useful in thermoluminescence dosimetry. -- Highlights: • Effect of Li{sup +} co-doping on ZnO:RE{sup 3+}(RE=Eu,Tb) nanorods were studied. • Formation of nanorods confirmed by SEM and TEM image. • No major change in XRD peak pattern on Li
Compilation of kinetic data for geochemical calculations
Energy Technology Data Exchange (ETDEWEB)
Arthur, R.C. [Monitor Scientific, LLC., Denver, Colorado (United States); Savage, D. [Quintessa, Ltd., Nottingham (United Kingdom); Sasamoto, Hiroshi; Shibata, Masahiro; Yui, Mikazu [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan). Tokai Works
2000-01-01
Kinetic data, including rate constants, reaction orders and activation energies, are compiled for 34 hydrolysis reactions involving feldspars, sheet silicates, zeolites, oxides, pyroxenes and amphiboles, and for similar reactions involving calcite and pyrite. The data are compatible with a rate law consistent with surface reaction control and transition-state theory, which is incorporated in the geochemical software package EQ3/6 and GWB. Kinetic data for the reactions noted above are strictly compatible with the transition-state rate law only under far-from-equilibrium conditions. It is possible that the data are conceptually consistent with this rate law under both far-from-equilibrium and near-to-equilibrium conditions, but this should be confirmed whenever possible through analysis of original experimental results. Due to limitations in the availability of kinetic data for mine-water reactions, and in order to simplify evaluations of geochemical models of groundwater evolution, it is convenient to assume local-equilibrium in such models whenever possible. To assess whether this assumption is reasonable, a modeling approach accounting for couple fluid flow and water-rock interaction is described that can be use to estimate spatial and temporal scale of local equilibrium. The approach is demonstrated for conditions involving groundwater flow in fractures at JNC's Kamaishi in-situ tests site, and is also used to estimate the travel time necessary for oxidizing surface waters to migrate to the level of a HLW repository in crystalline rock. The question of whether local equilibrium is a reasonable assumption must be addressed using an appropriate modeling approach. To be appropriate for conditions at the Kamaishi site using the modeling approach noted above, the fracture fill must closely approximate a porous mine, groundwater flow must be purely advective and diffusion of solutes across the fracture-host rock boundary must not occur. Moreover, the
Kinetic Parameter Measurements in the MINERVE Reactor
Perret, Grégory; Geslot, Benoit; Gruel, Adrien; Blaise, Patrick; Di-Salvo, Jacques; De Izarra, Grégoire; Jammes, Christian; Hursin, Mathieu; Pautz, Andréas
2017-01-01
In the framework of an international collaboration, teams of the PSI and CEA research institutes measure the critical decay constant (α0 = β/A), delayed neutron fraction (β) and generation time (A) of the Minerve reactor using the Feynman-α, Power Spectral Density and Rossi-α neutron noise measurement techniques. These measurements contribute to the experimental database of kinetic parameters used to improve nuclear data files and validate modern methods in Monte Carlo codes. Minerve is a zero-power pool reactor composed of a central experimental test lattice surrounded by a large aluminum buffer and four high-enriched driver regions. Measurements are performed in three slightly subcritical configurations (-2 cents to -30 cents) using two high-efficiency 235U fission chambers in the driver regions. Measurement of α0 and β obtained by the two institutes and with the different techniques are consistent for the configurations envisaged. Slight increases of the β values are observed with the subcriticality level. Best estimate values are obtained with the Cross-Power Spectral Density technique at -2 cents, and are worth: β = 716.9±9.0 pcm, α0 = 79.0±0.6 s-1 and A = 90.7±1.4 μs. The kinetic parameters are predicted with MCNP5-v1.6 and TRIPOLI4.9 and the JEFF-3.1/3.1.1 and ENDF/B-VII.1 nuclear data libraries. The predictions for β and α0 overestimate the experimental results by 3-5% and 10-12%, respectively; that for A underestimate the experimental result by 6-7%. The discrepancies are suspected to come from the driven system nature of Minerve and the location of the detectors in the driver regions, which prevent accounting for the full reactor.
Field-theoretic calculation of kinetic helicity flux
Indian Academy of Sciences (India)
bulence and compute the fluxes of energy and kinetic helicity. The renormalized viscosity computed using RG procedure is used in the calculation. Contrast this with the arbitrary constant used in EDQNM calculation. In addition, the EDQNM calculations require numerical integration of energy equation, which is not required.
Kinetic neoclassical calculations of impurity radiation profiles
Directory of Open Access Journals (Sweden)
D.P. Stotler
2017-08-01
Full Text Available Modifications of the drift-kinetic transport code XGC0 to include the transport, ionization, and recombination of individual charge states, as well as the associated radiation, are described. The code is first applied to a simulation of an NSTX H-mode discharge with carbon impurity to demonstrate the approach to coronal equilibrium. The effects of neoclassical phenomena on the radiated power profile are examined sequentially through the activation of individual physics modules in the code. Orbit squeezing and the neoclassical inward pinch result in increased radiation for temperatures above a few hundred eV and changes to the ratios of charge state emissions at a given electron temperature. Analogous simulations with a neon impurity yield qualitatively similar results.
A modified microdosimetric kinetic model for relative biological effectiveness calculation
Chen, Yizheng; Li, Junli; Li, Chunyan; Qiu, Rui; Wu, Zhen
2018-01-01
In the heavy ion therapy, not only the distribution of physical absorbed dose, but also the relative biological effectiveness (RBE) weighted dose needs to be taken into account. The microdosimetric kinetic model (MKM) can predict the RBE value of heavy ions with saturation-corrected dose-mean specific energy, which has been used in clinical treatment planning at the National Institute of Radiological Sciences. In the theoretical assumption of the MKM, the yield of the primary lesion is independent of the radiation quality, while the experimental data shows that DNA double strand break (DSB) yield, considered as the main primary lesion, depends on the LET of the particle. Besides, the β parameter of the MKM is constant with LET resulting from this assumption, which also differs from the experimental conclusion. In this study, a modified MKM was developed, named MMKM. Based on the experimental DSB yield of mammalian cells under the irradiation of ions with different LETs, a RBEDSB (RBE for the induction of DSB)-LET curve was fitted as the correction factor to modify the primary lesion yield in the MKM, and the variation of the primary lesion yield with LET is considered in the MMKM. Compared with the present the MKM, not only the α parameter of the MMKM for mono-energetic ions agree with the experimental data, but also the β parameter varies with LET and the variation trend of the experimental result can be reproduced on the whole. Then a spread-out Bragg peaks (SOBP) distribution of physical dose was simulated with Geant4 Monte Carlo code, and the biological and clinical dose distributions were calculated, under the irradiation of carbon ions. The results show that the distribution of clinical dose calculated with the MMKM is closed to the distribution with the MKM in the SOBP, while the discrepancy before and after the SOBP are both within 10%. Moreover, the MKM might overestimate the clinical dose at the distal end of the SOBP more than 5% because of its
Calculation the kinetics of the baking biscuit process
Directory of Open Access Journals (Sweden)
S. T. Antipov
2013-01-01
Full Text Available Based on the input values of the equivalent values of thermophysical units and the heat transfer coefficient were calculated: values that reflect the kinetics of the process of baking; values allowing to determine the relationship duration baking temperature in the baking chamber; the voltage of the active area of the hearth.
Kinetic measurements and quantum chemical calculations on low ...
Indian Academy of Sciences (India)
Home; Journals; Journal of Chemical Sciences; Volume 127; Issue 7. Kinetic measurements and quantum chemical calculations on low spin Ni(II)/(III) macrocyclic complexes in aqueous and sulphato medium. Anuradha Sankaran E J Padma Malar Venkatapuram Ramanujam Vijayaraghavan. Regular Articles Volume 127 ...
Mission Fuel Kinetics Input and RELAP-like Calculations
Energy Technology Data Exchange (ETDEWEB)
Pavlovichev, A.M.
2001-09-28
In this document issued according to ''Work Release 02. P. 99-4b'' the neutronics parameters intended for use in 1-point kinetics RELAP model are presented. They are obtained for equilibrium 30% MOX fueled core of VVER-1000 containing boron burnable poison rods.
Energy Technology Data Exchange (ETDEWEB)
McKenzie, IV, George Espy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Goda, Joetta Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Grove, Travis Justin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sanchez, Rene Gerardo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-04-17
This paper examines the comparison of MCNP® code’s capability to calculate kinetics parameters effectively for a thermal system containing highly enriched uranium (HEU). The Rossi-α parameter was chosen for this examination because it is relatively easy to measure as well as easy to calculate using MCNP®’s kopts card. The Rossi-α also incorporates many other parameters of interest in nuclear kinetics most of which are more difficult to precisely measure. The comparison looks at two different nuclear data libraries for comparison to the experimental data. These libraries are ENDF/BVI (.66c) and ENDF/BVII (.80c).
Kinetic-energy functionals studied by surface calculations
DEFF Research Database (Denmark)
Vitos, Levente; Skriver, Hans Lomholt; Kollár, J.
1998-01-01
The self-consistent jellium model of metal surfaces is used to study the accuracy of a number of semilocal kinetic-energy functionals for independent particles. It is shown that the poor accuracy exhibited by the gradient expansion approximation and most of the semiempirical functionals in the low...... density, high gradient limit may be subtantially improved by including locally a von Weizsacker term. Based on this, we propose a simple one-parameter Pade's approximation, which reproduces the exact Kohn-Sham surface kinetic energy over the entire range of metallic densities....
Estimation of Kinetic Parameters in an Automotive SCR Catalyst Model
DEFF Research Database (Denmark)
Åberg, Andreas; Widd, Anders; Abildskov, Jens
2016-01-01
A challenge during the development of models for simulation of the automotive Selective Catalytic Reduction catalyst is the parameter estimation of the kinetic parameters, which can be time consuming and problematic. The parameter estimation is often carried out on small-scale reactor tests......, or powder samples of the catalyst, which leads to problems when upscaling is done to the full-scale application. This contribution presents a methodology to sequentially estimate the kinetic parameters in 2 steps using steady-state limited small-scale reactor data, with the goal that the parameters should...
Accelerating quantum instanton calculations of the kinetic isotope effects.
Karandashev, Konstantin; Vaníček, Jiří
2015-11-21
Path integral implementation of the quantum instanton approximation currently belongs among the most accurate methods for computing quantum rate constants and kinetic isotope effects, but its use has been limited due to the rather high computational cost. Here, we demonstrate that the efficiency of quantum instanton calculations of the kinetic isotope effects can be increased by orders of magnitude by combining two approaches: The convergence to the quantum limit is accelerated by employing high-order path integral factorizations of the Boltzmann operator, while the statistical convergence is improved by implementing virial estimators for relevant quantities. After deriving several new virial estimators for the high-order factorization and evaluating the resulting increase in efficiency, using ⋅Hα + HβHγ → HαHβ + ⋅ Hγ reaction as an example, we apply the proposed method to obtain several kinetic isotope effects on CH4 + ⋅ H ⇌ ⋅ CH3 + H2 forward and backward reactions.
Spatial Kinetics Calculations of MOX Fueled Core: Variant 22
Energy Technology Data Exchange (ETDEWEB)
Pavlovichev, A.M.
2001-01-11
This work is part of a Joint US/Russian Project with Weapons-Grade Plutonium Disposition in VVER Reactors and presents the results of spatial kinetics calculational benchmarks. The examinations were carried out with the following purposes: to verify one of spatial neutronic kinetics model elaborated in KI, to understand sensibility of the model to neutronics difference of UOX and MOX cores, to compare in future point and spatial kinetics models (on the base of a set of selected accidents) in view of eventual creation of RELAP option with 3D kinetics. The document contains input data and results of model operation of three emergency dynamic processes in the VVER-1000 core: central control rod ejection by pressure drop caused by destroying of the moving mechanism cover; overcooling of the reactor core caused by steam line rupture and non-closure of steam generator stop valve; and the boron dilution of coolant in part of the VVER-1000 core caused by penetration of the distillate slug into the core at start up of non-working loop.
Influence of fission spectra uncertainties on calculated fast reactor parameters
Energy Technology Data Exchange (ETDEWEB)
Lucius, J.L.; Marable, J.H.
1979-01-01
The effect of fission spectra uncertainties on calculated fast reactor parameters is studied by (1) considering the sensitivities to fission spectrum parameters of four performance parameters in the fast reactor benchmark ZPR-6/7, (2) estimating the uncertainties in these calculated performance parameters due to uncertainties in the fission spectra, (3) reporting the change in ZPR-6/7 calculated performance parameters due to fission spectra changes going from ENDF/B-IV to proposed ENDF/B-VP, and (4) determining what fast benchmark integral experiments are trying to tell us about ENDF/B-IV fission spectrum parameters as variables in a least squares adjustment procedure.
Calculation of electromagnetic parameter based on interpolation algorithm
Energy Technology Data Exchange (ETDEWEB)
Zhang, Wenqiang, E-mail: zwqcau@gmail.com [College of Engineering, China Agricultural University, Beijing 100083 (China); Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, Beihang University, Beijing 100191 (China); Yuan, Liming; Zhang, Deyuan [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, Beihang University, Beijing 100191 (China)
2015-11-01
Wave-absorbing material is an important functional material of electromagnetic protection. The wave-absorbing characteristics depend on the electromagnetic parameter of mixed media. In order to accurately predict the electromagnetic parameter of mixed media and facilitate the design of wave-absorbing material, based on the electromagnetic parameters of spherical and flaky carbonyl iron mixture of paraffin base, this paper studied two different interpolation methods: Lagrange interpolation and Hermite interpolation of electromagnetic parameters. The results showed that Hermite interpolation is more accurate than the Lagrange interpolation, and the reflectance calculated with the electromagnetic parameter obtained by interpolation is consistent with that obtained through experiment on the whole. - Highlights: • We use interpolation algorithm on calculation of EM-parameter with limited samples. • Interpolation method can predict EM-parameter well with different particles added. • Hermite interpolation is more accurate than Lagrange interpolation. • Calculating RL based on interpolation is consistent with calculating RL from experiment.
Study on numerical calculation method for hydrodynamic parameters of WEC
Directory of Open Access Journals (Sweden)
Lijiao Shen
2017-01-01
Full Text Available For the effect of hydrodynamic parameters on the dynamic performance of wave energy devices is very significant, these parameters must be considered carefully when adjusting dynamic characteristics of devices. On the other hand calculating hydrodynamic parameter of devices accurately can guarantee rational dynamic property parameter adjustment. By using CFD technique and considering the definition of hydrodynamic parameters, the phase relationship between added mass and damp as well as the equation of forces, one new calculation method of hydrodynamic parameter was presented. Finally one example demonstrated the effectiveness of the new analysis method presented in this paper.
MCNP5 study on kinetics parameters of coupled fast-thermal system HERBE
Directory of Open Access Journals (Sweden)
Pešić Milan P.
2011-01-01
Full Text Available New validation of the well-known Monte Carlo code MCNP5 against measured criticality and kinetics data for the coupled fast-thermal HERBE System at the Reactor B critical assembly is shown in this paper. Results of earlier calculations of these criticality and kinetics parameters, done by combination of transport and diffusion codes using two-dimension geometry model are compared to results of new calculations carried out by the MCNP5 code in three-dimension geometry. Satisfactory agreements in comparison of new results with experimental data, in spite complex heterogeneous composition of the HERBE core, are achieved confirming that MCNP5 code could apply successfully to study on HERBE kinetics parameters after uncertainties in impurities in material compositions and positions of fuel elements in fast zone were removed.
Calculating Cutting Thermal Physics Parameters of Plastic Materials
Directory of Open Access Journals (Sweden)
S. V. Grubyi
2017-01-01
Full Text Available The thermal physics parameters and a cutting temperature belong to the output performances to characterise a process and allow a rational selection of machining modes and conditions. In machining hard-to-cut materials the utmost cutting temperature is a technological restriction and defines tool wear rate and intensity. The cutting temperature also has impact on the heat extension of tool and the finished machining.The subject is to study thermal physics parameters and cutting temperature when machining the plastic materials by a hard-alloy tool. The objective is to develop a technique to calculate these parameters. A calculation method for the analysis of process parameters is used.Calculation results for the cutting temperature were compared with experimental ones published in the literature sources. A novelty of the technique is that there is no need in conducting the experimental studies to calculate the thermal physics parameters. Calculation is based on using known mechanical and thermal physics characteristics of machined and tool materials. The calculation results are parameters, namely heat flow intensities in the conditional shear plane, on the contact surfaces of tool, temperatures of theses surfaces, averaged cutting temperature - depending on the cutting speed, thickness of cutting layer, tool wear value.A sequence of calculations is implemented in the developed software in the programming algorithmic language with results in graphic and tabular representations. The calculation technique is designed for conducting research activities and engineering designs in the field of machining.
Robust Nonlinear Regression in Enzyme Kinetic Parameters Estimation
Directory of Open Access Journals (Sweden)
Maja Marasović
2017-01-01
Full Text Available Accurate estimation of essential enzyme kinetic parameters, such as Km and Vmax, is very important in modern biology. To this date, linearization of kinetic equations is still widely established practice for determining these parameters in chemical and enzyme catalysis. Although simplicity of linear optimization is alluring, these methods have certain pitfalls due to which they more often then not result in misleading estimation of enzyme parameters. In order to obtain more accurate predictions of parameter values, the use of nonlinear least-squares fitting techniques is recommended. However, when there are outliers present in the data, these techniques become unreliable. This paper proposes the use of a robust nonlinear regression estimator based on modified Tukey’s biweight function that can provide more resilient results in the presence of outliers and/or influential observations. Real and synthetic kinetic data have been used to test our approach. Monte Carlo simulations are performed to illustrate the efficacy and the robustness of the biweight estimator in comparison with the standard linearization methods and the ordinary least-squares nonlinear regression. We then apply this method to experimental data for the tyrosinase enzyme (EC 1.14.18.1 extracted from Solanum tuberosum, Agaricus bisporus, and Pleurotus ostreatus. The results on both artificial and experimental data clearly show that the proposed robust estimator can be successfully employed to determine accurate values of Km and Vmax.
Borana, Mohanish S; Mishra, Pushpa; Pissurlenkar, Raghuvir R S; Hosur, Ramakrishna V; Ahmad, Basir
2014-03-01
Interaction of small molecule inhibitors with protein aggregates has been studied extensively, but how these inhibitors modulate aggregation kinetic parameters is little understood. In this work, we investigated the ability of two potential aggregation inhibiting drugs, curcumin and kaempferol, to control the kinetic parameters of aggregation reaction. Using thioflavin T fluorescence and static light scattering, the kinetic parameters such as amplitude, elongation rate constant and lag time of guanidine hydrochloride-induced aggregation reactions of hen egg white lysozyme were studied. We observed a contrasting effect of inhibitors on the kinetic parameters when aggregation reactions were measured by these two probes. The interactions of these inhibitors with hen egg white lysozyme were investigated using fluorescence quench titration method and molecular dynamics simulations coupled with binding free energy calculations. We conclude that both the inhibitors prolong nucleation of amyloid aggregation through binding to region of the protein which is known to form the core of the protein fibril, but once the nucleus is formed the rate of elongation is not affected by the inhibitors. This work would provide insight into the mechanism of aggregation inhibition by these potential drug molecules. Copyright © 2014 Elsevier B.V. All rights reserved.
Development of new model for high explosives detonation parameters calculation
Directory of Open Access Journals (Sweden)
Jeremić Radun
2012-01-01
Full Text Available The simple semi-empirical model for calculation of detonation pressure and velocity for CHNO explosives has been developed, which is based on experimental values of detonation parameters. Model uses Avakyan’s method for determination of detonation products' chemical composition, and is applicable in wide range of densities. Compared with the well-known Kamlet's method and numerical model of detonation based on BKW EOS, the calculated values from proposed model have significantly better accuracy.
Thermodynamic criteria for estimating the kinetic parameters of catalytic reactions
Mitrichev, I. I.; Zhensa, A. V.; Kol'tsova, E. M.
2017-01-01
Kinetic parameters are estimated using two criteria in addition to the traditional criterion that considers the consistency between experimental and modeled conversion data: thermodynamic consistency and the consistency with entropy production (i.e., the absolute rate of the change in entropy due to exchange with the environment is consistent with the rate of entropy production in the steady state). A special procedure is developed and executed on a computer to achieve the thermodynamic consistency of a set of kinetic parameters with respect to both the standard entropy of a reaction and the standard enthalpy of a reaction. A problem of multi-criterion optimization, reduced to a single-criterion problem by summing weighted values of the three criteria listed above, is solved. Using the reaction of NO reduction with CO on a platinum catalyst as an example, it is shown that the set of parameters proposed by D.B. Mantri and P. Aghalayam gives much worse agreement with experimental values than the set obtained on the basis of three criteria: the sum of the squares of deviations for conversion, the thermodynamic consistency, and the consistency with entropy production.
Calculation Method of Kinetic Constants for the Mathematical Model Peat Pyrolysis
Directory of Open Access Journals (Sweden)
Plakhova Tatyana
2014-01-01
Full Text Available Relevance of the work is related to necessity to simplify the calculation of kinetic constants for the mathematical model peat pyrolysis. Execute transformations of formula Arrhenius law. Degree of conversion is expressed in terms mass changes of sample. The obtained formulas help to calculate the kinetic constants for any type of solid organic fuels
Parameter analysis calculation on characteristics of portable FAST reactor
Energy Technology Data Exchange (ETDEWEB)
Otsubo, Akira; Kowata, Yasuki [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center
1998-06-01
In this report, we performed a parameter survey analysis by using the analysis program code STEDFAST (Space, TErrestrial and Deep sea FAST reactor-gas turbine system). Concerning the deep sea fast reactor-gas turbine system, calculations with many variable parameters were performed on the base case of a NaK cooled reactor of 40 kWe. We aimed at total equipment weight and surface area necessary to remove heat from the system as important values of the characteristics of the system. Electric generation power and the material of a pressure hull were specially influential for the weight. The electric generation power, reactor outlet/inlet temperatures, a natural convection heat transfer coefficient of sea water were specially influential for the area. Concerning the space reactor-gas turbine system, the calculations with the variable parameters of compressor inlet temperature, reactor outlet/inlet temperatures and turbine inlet pressure were performed on the base case of a Na cooled reactor of 40 kWe. The first and the second variable parameters were influential for the total equipment weight of the important characteristic of the system. Concerning the terrestrial fast reactor-gas turbine system, the calculations with the variable parameters of heat transferred pipe number in a heat exchanger to produce hot water of 100degC for cogeneration, compressor stage number and the kind of primary coolant material were performed on the base case of a Pb cooled reactor of 100 MWt. In the comparison of calculational results for Pb and Na of primary coolant material, the primary coolant weight flow rate was naturally large for the former case compared with for the latter case because density is very different between them. (J.P.N.)
Modified mean generation time parameter in the neutron point kinetics equations
Energy Technology Data Exchange (ETDEWEB)
Diniz, Rodrigo C.; Gonçalves, Alessandro C.; Rosa, Felipe S.S., E-mail: alessandro@nuclear.ufrj.br, E-mail: frosa@if.ufrj.br [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil)
2017-07-01
This paper proposes an approximation for the modified point kinetics equations proposed by NUNES et. al, 2015, through the adjustment of a kinetic parameter. This approximation consists of analyzing the terms of the modified point kinetics equations in order to identify the least important ones for the solution, resulting in a modification of the mean generation time parameter that incorporates all influences of the additional terms of the modified kinetics. This approximation is applied on the inverse kinetics, to compare the results with the inverse kinetics from the modified kinetics in order to validate the proposed model. (author)
Software for calculation of electric power systems parameters
Energy Technology Data Exchange (ETDEWEB)
Rodriguez, Gustavo; Aromataris, Luis; Donolo, Marcos; Hernandez, Jose; Moitre, Diego [Universidad Nacional de Rio Cuarto, Grupo de Analisis de Sistemas Electricos de Potencia (GASEP), Cordoba (Argentina)
2003-07-01
The calculation of power transmission lines parameters of electric energy has a fundamental importance in the design, construction and simulation of electric power systems. Generally, the results obtained are used in the database for the studies of power flow, short circuit and stability . This paper presents a software with graphical interface which allows the estimation of parameters of power transmission lines of electric energy. By means of a tutorial, the user is oriented step by step about the input of data and other features of the line, passing to the calculation stage when the data are correctly and completely entered. The output of the results is shown on the screen on a Pi circuit and through graphics that simulate the voltage drop for a determined load. (Author)
Kinetic parameters of silicon uptake by rice cultivars
Directory of Open Access Journals (Sweden)
Priscila Oliveira Martins
2012-02-01
Full Text Available Silicon is considered an important chemical element for rice, because it can improve tolerance to biotic and abiotic stress. However, in many situations no positive effect of silicon was observed, probably due to genetic factors. The objective of this research was to monitor Si uptake kinetics and identify responses of rice cultivars in terms of Si uptake capacity and use. The experiment was carried out in a greenhouse of the São Paulo State University (UNESP, Brazil. The experiment was arranged in a completely randomized, factorial design with three replications. that consisted of two rice cultivars and two Si levels. Kinetic parameters (Vmax, Km, and Cmin, root morphology variables, dry matter yield, Si accumulation and levels in shoots and roots, uptake efficiency, utilization efficiency, and root/shoot ratio were evaluated. Higher Si concentrations in the nutrient solution did not increase rice dry matter. The development of the low-affinity silicon uptake system of the rice cultivar 'Caiapó' was better than of 'Maravilha'.
Achieving High Accuracy in Calculations of NMR Parameters
DEFF Research Database (Denmark)
Faber, Rasmus
information about the relative positions of nuclei are also obtained. Due to the widespread use of NMR spectroscopy, there is a keen interest in theoretical predictions of the relevant parameters, the nuclear shielding constants and indirect nuclear spin-spin coupling constants (SSCC). Though highly advanced...... calculations are today typically based on coupled cluster (CC) theory. The CCSD(T) method is very popular and is known to give accurate results for a wide range of molecular properties, including nuclear shielding constants, but not SSCCs. An alternative to CCSD(T) for calculating SSCCs could be the CC3 method...... that CC3 captures important correlation effects ignored by the previous standard method, CCSD. Indeed, CC3 is shown to accurately reproduce gas-phase experimental results for the SSCCs of acetylene. In any molecular property calculation the one-electron basis set must be chosen with care as the basis set...
Seldam, C.A. ten; Groot, S.R. de
1952-01-01
From Jensen's and Gombás' modification of the statistical Thomas-Fermi atom model, a theory for compressed atoms is developed by changing the boundary conditions. Internal kinetic energy and polarizability of argon are calculated as functions of pressure. At 1000 atm. an internal kinetic energy of
Reflected kinetics model for nuclear space reactor kinetics and control scoping calculations
Energy Technology Data Exchange (ETDEWEB)
Washington, K.E.
1986-05-01
The objective of this research is to develop a model that offers an alternative to the point kinetics (PK) modelling approach in the analysis of space reactor kinetics and control studies. Modelling effort will focus on the explicit treatment of control drums as reactivity input devices so that the transition to automatic control can be smoothly done. The proposed model is developed for the specific integration of automatic control and the solution of the servo mechanism problem. The integration of the kinetics model with an automatic controller will provide a useful tool for performing space reactor scoping studies for different designs and configurations. Such a tool should prove to be invaluable in the design phase of a space nuclear system from the point of view of kinetics and control limitations.
NAFTA Guidance for Evaluating and Calculating Degradation Kinetics in Environmental Media :DD Memo
Signed Division Director memo, December 17, 2012, with original announcement to EFED scientists of tools and approaches for evaluating and calculating degradation kinetics in environmental media. There is more updated information that this available.
Ordinary Mathematical Models in Calculating the Aviation GTE Parameters
Directory of Open Access Journals (Sweden)
E. A. Khoreva
2017-01-01
Full Text Available The paper presents the analytical review results of the ordinary mathematical models of the operating process used to study aviation GTE parameters and characteristics at all stages of its creation and operation. Considers the mathematical models of the zero and the first level, which are mostly used when solving typical problems in calculating parameters and characteristics of engines.Presents a number of practical problems arising in designing aviation GTE for various applications.The application of mathematical models of the zero-level engine can be quite appropriate when the engine is considered as a component in the aircraft system to estimate its calculated individual flight performance or when modeling the flight cycle of the aircrafts of different purpose.The paper demonstrates that introduction of correction functions into the first-level mathematical models in solving typical problems (influence of the Reynolds number, characteristics deterioration of the units during the overhaul period of engine, as well as influence of the flow inhomogeneity at the inlet because of manufacturing tolerance, etc. enables providing a sufficient engineering estimate accuracy to reflect a realistic operating process in the engine and its elements.
WIPP shaft seal system parameters recommended to support compliance calculations
Energy Technology Data Exchange (ETDEWEB)
Hurtado, L.D.; Knowles, M.K. [Sandia National Labs., Albuquerque, NM (United States); Kelley, V.A.; Jones, T.L.; Ogintz, J.B. [INTERA Inc., Austin, TX (United States); Pfeifle, T.W. [RE/SPEC, Inc., Rapid City, SD (United States)
1997-12-01
The US Department of Energy plans to dispose of transuranic waste at the Waste Isolation Pilot Plant (WIPP), which is sited in southeastern New Mexico. The WIPP disposal facility is located approximately 2,150 feet (650 m) below surface in the bedded halite of the Salado Formation. Prior to initiation of disposal activities, the Department of Energy must demonstrate that the WIPP will comply with all regulatory requirements. Applicable regulations require that contaminant releases from the WIPP remain below specified levels for a period of 10,000 years. To demonstrate that the WIPP will comply with these regulations, the Department of Energy has requested that Sandia National Laboratories develop and implement a comprehensive performance assessment of the WIPP repository for the regulatory period. This document presents the conceptual model of the shaft sealing system to be implemented in performance assessment calculations conducted in support of the Compliance Certification Application for the WIPP. The model was developed for use in repository-scale calculations and includes the seal system geometry and materials to be used in grid development as well as all parameters needed to describe the seal materials. These calculations predict the hydrologic behavior of the system. Hence conceptual model development is limited to those processes that could impact the fluid flow through the seal system.
Determination of the kinetic parameters of Be O using isothermal decay method
Energy Technology Data Exchange (ETDEWEB)
Azorin N, J.; Torijano C, E. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico D. F. (Mexico); Azorin V, C.; Rivera M, T., E-mail: azorin@xanum.uam.mx [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico)
2015-10-15
Full text: Most of the existing methods for obtaining the frequency factors make use of the trap depth (activation energy) making some assumptions about the order of the kinetics. This causes inconsistencies in the reported values of trapping parameters due that the values of the activation energy obtained by different methods differ appreciably among them. Then, it is necessary to use a method independent of the trap depth making use of the isothermal luminescence decay method. The trapping parameters associated with the prominent glow peak of Be O (280 degrees C) are reported using isothermal luminescence decay method. As a check, the trap parameters are also calculated by glow curve shape (Chen s) method after isolating the prominent glow peak by thermal cleaning technique. Our results show a very good agreement between the trapping parameters calculated by the two methods. Isothermal luminescence decay method was used for determining the trapping parameters of Be O. Results obtained applying this method are in good agreement with those obtained using other methods, except in the value of the frequency factor. (Author)
Improved Parameter-Estimation With MRI-Constrained PET Kinetic Modeling: A Simulation Study
Erlandsson, Kjell; Liljeroth, Maria; Atkinson, David; Arridge, Simon; Ourselin, Sebastien; Hutton, Brian F.
2016-10-01
Kinetic analysis can be applied both to dynamic PET and dynamic contrast enhanced (DCE) MRI data. We have investigated the potential of MRI-constrained PET kinetic modeling using simulated [ 18F]2-FDG data for skeletal muscle. The volume of distribution, Ve, for the extra-vascular extra-cellular space (EES) is the link between the two models: It can be estimated by DCE-MRI, and then used to reduce the number of parameters to estimate in the PET model. We used a 3 tissue-compartment model with 5 rate constants (3TC5k), in order to distinguish between EES and the intra-cellular space (ICS). Time-activity curves were generated by simulation using the 3TC5k model for 3 different Ve values under basal and insulin stimulated conditions. Noise was added and the data were fitted with the 2TC3k model and with the 3TC5k model with and without Ve constraint. One hundred noise-realisations were generated at 4 different noise-levels. The results showed reductions in bias and variance with Ve constraint in the 3TC5k model. We calculated the parameter k3", representing the combined effect of glucose transport across the cellular membrane and phosphorylation, as an extra outcome measure. For k3", the average coefficient of variation was reduced from 52% to 9.7%, while for k3 in the standard 2TC3k model it was 3.4%. The accuracy of the parameters estimated with our new modeling approach depends on the accuracy of the assumed Ve value. In conclusion, we have shown that, by utilising information that could be obtained from DCE-MRI in the kinetic analysis of [ 18F]2-FDG-PET data, it is in principle possible to obtain better parameter estimates with a more complex model, which may provide additional information as compared to the standard model.
Bozkoyunlu, Gaye; Takaç, Serpil
2014-01-01
Olive mill wastewater (OMW) with total phenol (TP) concentration range of 300-1200 mg/L was treated with alginate-immobilized Rhodotorula glutinis cells in batch system. The effects of pellet properties (diameter, alginate concentration and cell loading (CL)) and operational parameters (initial TP concentration, agitation rate and reusability of pellets) on dephenolization of OMW were studied. Up to 87% dephenolization was obtained after 120 h biodegradations. The utilization number of pellets increased with the addition of calcium ions into the biodegradation medium. The overall effectiveness factors calculated for different conditions showed that diffusional limitations arising from pellet size and pellet composition could be neglected. Mass transfer limitations appeared to be more effective at high substrate concentrations and low agitation rates. The parameters of logistic model for growth kinetics of R. glutinis in OMW were estimated at different initial phenol concentrations of OMW by curve-fitting of experimental data with the model.
TL kinetics parameters of MWCVD diamond films at different gamma dose rate
Energy Technology Data Exchange (ETDEWEB)
Cruz Z, E.; Furetta, C. [ICN, UNAM, A.P. 70-543, 04510 Mexico D.F. (Mexico); Favalli, A. [European Commission, Joint Research Centre, Institute for the Protection and Security of Citizen, TP800, Via E Fermi 21020, Ispra, VA (Italy); Gastelum, S.; Melendrez, R.; Barboza F, M. [CIF, Universidad de Sonora, A.P. 5-088, 83190 Hermosillo, Sonora (Mexico)
2007-07-01
Full text: Microwave chemically vapour deposited (MWCVD) diamond films have been successfully used in dosimetric applications including radiotherapy and industrial dose assessments. Dose measurements were determined by integration of the TL glow curve of a MWCVD diamond films previously exposed to an ionizing radiation beam. A good quality MWCVD diamond films thermoluminescent dosimeter (TLD) should be independent of the irradiation dose rate used. In the present work the TL kinetics parameters of the MWCVD diamond films of 6 and 12 lm thickness, exposed to different {sup 60}Co gamma dose rates of 2.4, 5.94 and 13.1 Gy/min were calculated through a Computerized Glow Curve Deconvolution (CGCD) method. The TL glow curves feature a single peak at different dose rates with asymmetric shape typical of a first order kinetics process. The experimental TL glow curves were fitted using first-order kinetics and the best fit showed FOM values around 2-3 % range indicating the goodness of the fit. Slight dose rate effects on the TL properties were observed as compared to higher dose rates TL dependences reported elsewhere. (Author)
Chemical kinetics parameters and model validation for the gasification of PCEA nuclear graphite
Energy Technology Data Exchange (ETDEWEB)
El-Genk, Mohamed S [University of New Mexico, Albuquerque; Tournier, Jean-Michel [University of New Mexico, Albuquerque; Contescu, Cristian I [ORNL
2014-01-01
A series of gasification experiments, using two right cylinder specimens (~ 12.7 x 25.4 mm and 25.4 x 25.4 mm) of PCEA nuclear graphite in ambient airflow, measured the total gasification flux at weight losses up to 41.5% and temperatures (893-1015 K) characteristics of those for in-pores gasification Mode (a) and in-pores diffusion-limited Mode (b). The chemical kinetics parameters for the gasification of PCEA graphite are determined using a multi-parameters optimization algorithm from the measurements of the total gasification rate and transient weight loss in experiments. These parameters are: (i) the pre-exponential rate coefficients and the Gaussian distributions and values of specific activation energies for adsorption of oxygen and desorption of CO gas; (ii) the specific activation energy and pre-exponential rate coefficient for the breakup of stable un-dissociated C(O2) oxygen radicals to form stable (CO) complexes; (iii) the specific activation energy and pre-exponential coefficient for desorption of CO2 gas and; (iv) the initial surface area of reactive free sites per unit mass. This area is consistently 13.5% higher than that for nuclear graphite grades of NBG-25 and IG-110 and decreases inversely proportional with the square root of the initial mass of the graphite specimens in the experiments. Experimental measurements successfully validate the chemical-reactions kinetics model that calculates continuous Arrhenius curves of the total gasification flux and the production rates of CO and CO2 gases. The model results at different total weight losses agree well with measurements and expand beyond the temperatures in the experiments to the diffusion-limited mode of gasification. Also calculated are the production rates of CO and CO2 gases and their relative contributions to the total gasification rate in the experiments as functions of temperature, for total weight losses of 5% and 10%.
Chemical kinetics parameters and model validation for the gasification of PCEA nuclear graphite
Energy Technology Data Exchange (ETDEWEB)
El-Genk, Mohamed S., E-mail: mgenk@unm.edu [Institute for Space and Nuclear Power Studies, University of New Mexico, Albuquerque, NM (United States); Chemical and Nuclear Engineering Dept., University of New Mexico, Albuquerque, NM (United States); Mechanical Engineering Dept., University of New Mexico, Albuquerque, NM (United States); Tournier, Jean-Michel P. [Institute for Space and Nuclear Power Studies, University of New Mexico, Albuquerque, NM (United States); Contescu, Cristian I. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)
2014-01-15
A series of gasification experiments, using two right cylinder specimens (∼12.7 × 25.4 mm and 25.4 × 25.4 mm) of PCEA nuclear graphite in ambient airflow, measured the total gasification flux at weight losses up to 41.5% and temperatures (893–1015 K) characteristics of those for in-pores gasification Mode (a) and in-pores diffusion-limited Mode (b). The chemical kinetics parameters for the gasification of PCEA graphite are determined using a multi-parameters optimization algorithm from the measurements of the total gasification rate and transient weight loss in experiments. These parameters are: (i) the pre-exponential rate coefficients and the Gaussian distributions and values of specific activation energies for adsorption of oxygen and desorption of CO gas; (ii) the specific activation energy and pre-exponential rate coefficient for the breakup of stable un-dissociated C(O{sub 2}) oxygen radicals to form stable (CO) complexes; (iii) the specific activation energy and pre-exponential coefficient for desorption of CO{sub 2} gas and; (iv) the initial surface area of reactive free sites per unit mass. This area is consistently 13.5% higher than that for nuclear graphite grades of NBG-25 and IG-110 and decreases inversely proportional with the square root of the initial mass of the graphite specimens in the experiments. Experimental measurements successfully validate the chemical-reactions kinetics model that calculates continuous Arrhenius curves of the total gasification flux and the production rates of CO and CO{sub 2} gases. The model results at different total weight losses agree well with measurements and expand beyond the temperatures in the experiments to the diffusion-limited mode of gasification. Also calculated are the production rates of CO and CO{sub 2} gases and their relative contributions to the total gasification rate in the experiments as functions of temperature, for total weight losses of 5% and 10%.
Ahmad, Muhammad Sajjad; Mehmood, Muhammad Aamer; Taqvi, Syed Taha Haider; Elkamel, Ali; Liu, Chen-Guang; Xu, Jianren; Rahimuddin, Sawsan Abdulaziz; Gull, Munazza
2017-12-01
This work was focused on understanding the pyrolysis of Typha latifolia. Kinetics, thermodynamics parameters and pyrolysis reaction mechanism were studied using thermogravimetric data. Based on activation energies and conversion points, two regions of pyrolysis were established. Region-I occurred between the conversion rate 0.1-0.4 with peak temperatures 538K, 555K, 556K at the heating rates of 10Kmin-1, 30Kmin-1, and 50Kmin-1, respectively. Similarly, the Region-II occurred between 0.4 and 0.8 with peak temperatures of 606K, 621K, 623K at same heating rates. The best model was diffusion mechanism in Region-I. In Region-II, the reaction order was shown to be 2nd and 3rd. The values of activation energy calculated using FWO and KAS methods (134-204kJmol-1) remained same in both regions reflecting that the best reaction mechanism was predicted. Kinetics and thermodynamic parameters including E, ΔH, ΔS, ΔG shown that T. latifolia biomass is a remarkable feedstock for bioenergy. Copyright © 2017 Elsevier Ltd. All rights reserved.
Castillo, Eduardo; Pérez, María Dolores; Franco, Indira; Calvo, Miguel; Sánchez, Lourdes
2012-06-01
Heat denaturation of recombinant human lactoferrin (rhLf) from rice with 3 different iron-saturation degrees, holo rhLf (iron-saturated), AsIs rhLf (60% iron saturation), and apo rhLf (iron-depleted), was studied. The 3 forms of rhLf were subjected to heat treatment, and the kinetic and thermodynamic parameters of the denaturation process were determined. Thermal denaturation of rhLf was assessed by measuring the loss of reactivity against specific antibodies. D(t) values (time to reduce 90% of immunoreactivity) decreased with increasing temperature of treatment for apo and holo rhLf, those values being higher for the iron-saturated form, which indicates that iron confers thermal stability to rhLf. However, AsIs rhLf showed a different behaviour with an increase in resistance to heat between 79 °C and 84 °C, so that the kinetic parameters could not be calculated. The heat denaturation process for apo and holo rhLf was best described assuming a reaction order of 1.5. The activation energy of the denaturation process was 648.20 kJ/mol for holo rhLf and 406.94 kJ/mol for apo rhLf, confirming that iron-depleted rhLf is more sensitive to heat treatment than iron-saturated rhLf.
Development of simple kinetic models and parameter estimation for ...
African Journals Online (AJOL)
The growth of P. pastoris on both glycerol and methanol could be represented by Monod kinetic equation. A simple simulation methodology and developed models were shown to satisfactorily describe both growth and production of recombinant human serum albumin (rHSA) using a genetically modified P. pastoris MutS ...
Kinetic models and parameters estimation study of biomass and ...
African Journals Online (AJOL)
The growth kinetics and modeling of ethanol production from inulin by Pichia caribbica (KC977491) were studied in a batch system. Unstructured models were proposed using the logistic equation for growth, the Luedeking-Piret equation for ethanol production and modified Leudeking-Piret model for substrate consumption.
Kinetic models and parameters estimation study of biomass and ...
African Journals Online (AJOL)
compaq
2017-01-11
Jan 11, 2017 ... The growth kinetics and modeling of ethanol production from inulin by Pichia caribbica (KC977491) were studied in a batch system. Unstructured models were proposed using the logistic equation for growth, the Luedeking-Piret equation for ethanol production and modified Leudeking-Piret model for.
Tohsato, Yukako; Ikuta, Kunihiko; Shionoya, Akitaka; Mazaki, Yusaku; Ito, Masahiro
2013-04-10
Dynamic modeling is a powerful tool for predicting changes in metabolic regulation. However, a large number of input parameters, including kinetic constants and initial metabolite concentrations, are required to construct a kinetic model. Therefore, it is important not only to optimize the kinetic parameters, but also to investigate the effects of their perturbations on the overall system. We investigated the efficiency of the use of a real-coded genetic algorithm (RCGA) for parameter optimization and sensitivity analysis in the case of a large kinetic model involving glycolysis and the pentose phosphate pathway in Escherichia coli K-12. Sensitivity analysis of the kinetic model using an RCGA demonstrated that the input parameter values had different effects on model outputs. The results showed highly influential parameters in the model and their allowable ranges for maintaining metabolite-level stability. Furthermore, it was revealed that changes in these influential parameters may complement one another. This study presents an efficient approach based on the use of an RCGA for optimizing and analyzing parameters in large kinetic models. Copyright © 2012 Elsevier B.V. All rights reserved.
Effect of kinetic parameters on heterologous protein production: a sysbio approach
DEFF Research Database (Denmark)
Nandy, Subir Kumar; Rattleff, Stig; Thykær, Jette
To improve the expression and secretion of heterologous proteins in the filamentous grampositive bacteria, Streptomyces lividans, bioprocessing strategies were developed. A mathematical model was constructed to study the effects of the process kinetic parameters on the production of the model...
Parameter Estimates in Differential Equation Models for Chemical Kinetics
Winkel, Brian
2011-01-01
We discuss the need for devoting time in differential equations courses to modelling and the completion of the modelling process with efforts to estimate the parameters in the models using data. We estimate the parameters present in several differential equation models of chemical reactions of order n, where n = 0, 1, 2, and apply more general…
A robust methodology for kinetic model parameter estimation for biocatalytic reactions
DEFF Research Database (Denmark)
Al-Haque, Naweed; Andrade Santacoloma, Paloma de Gracia; Lima Afonso Neto, Watson
2012-01-01
Effective estimation of parameters in biocatalytic reaction kinetic expressions are very important when building process models to enable evaluation of process technology options and alternative biocatalysts. The kinetic models used to describe enzyme-catalyzed reactions generally include several...... lead to globally optimized parameter values. In this article, a robust methodology to estimate parameters for biocatalytic reaction kinetic expressions is proposed. The methodology determines the parameters in a systematic manner by exploiting the best features of several of the current approaches....... The parameter estimation problem is decomposed into five hierarchical steps, where the solution of each of the steps becomes the input for the subsequent step to achieve the final model with the corresponding regressed parameters. The model is further used for validating its performance and determining...
Kinetic parameter estimation and fluctuation analysis of CO at SnO 2 single nanowires
Tulzer, Gerhard
2013-07-12
In this work, we present calculated numerical values for the kinetic parameters governing adsorption/desorption processes of carbon monoxide at tin dioxide single-nanowire gas sensors. The response of such sensors to pulses of 50 ppm carbon monoxide in nitrogen is investigated at different temperatures to extract the desired information. A rate-equation approach is used to model the reaction kinetics, which results in the problem of determining coefficients in a coupled system of nonlinear ordinary differential equations. The numerical values are computed by inverse-modeling techniques and are then used to simulate the sensor response. With our model, the dynamic response of the sensor due to the gas-surface interaction can be studied in order to find the optimal setup for detection, which is an important step towards selectivity of these devices. We additionally investigate the noise in the current through the nanowire and its changes due to the presence of carbon monoxide in the sensor environment. Here, we propose the use of a wavelet transform to decompose the signal and analyze the noise in the experimental data. This method indicates that some fluctuations are specific for the gas species investigated here. © 2013 IOP Publishing Ltd.
Parameter Optimization of Nitriding Process Using Chemical Kinetics
Özdemir, İ. Bedii; Akar, Firat; Lippmann, Nils
2016-12-01
Using the dynamics of chemical kinetics, an investigation to search for an optimum condition for a gas nitriding process is performed over the solution space spanned by the initial temperature and gas composition of the furnace. For a two-component furnace atmosphere, the results are presented in temporal variations of gas concentrations and the nitrogen coverage on the surface. It seems that the exploitation of the nitriding kinetics can provide important feedback for setting the model-based control algorithms. The present work shows that when the nitrogen gas concentration is not allowed to exceed 6 pct, the Nad coverage can attain maximum values as high as 0.97. The time evolution of the Nad coverage also reveals that, as long as the temperature is above the value where nitrogen poisoning of the surface due to the low-temperature adsorption of excess nitrogen occurs, the initial ammonia content in the furnace atmosphere is much more important in the nitriding process than is the initial temperature.
Variational Calculation of Effective Parameters in Random Porous Media
Hristopulos, Dionissios T.; Christakos, George
1998-03-01
Effective parameters are used in stochastic hydrology and petroleum engineering as estimates of the coarse-grained behavior of fluid flow and transport. Stochastic effective parameter estimation involves averaging over the local heterogeneity. Explicit evaluation methods are often based on low order perturbation expansions. We obtain more general estimates using a variational scheme that employs auxiliary probability measures. The average over the local fluctuations is evaluated by means of the logarithm transform and the replica trick. The equations satisfied by the effective parameters are obtained variationally from an effective free energy functional. We use this method for the evaluation of the effective permeability of random porous media with Gaussian local fluctuations. The resulting equations are solved explicitly in specific cases, and the results are compared with leading-order perturbation estimates and experimental data. Explicit finite-size expressions are obtained using momentum-space filters. The implications of the finite size behavior for the scaleup problem are discussed.
Calculation of parameters of combined frame and roof bolting
Ivanov, S. I.; Titov, N. V.; Privalov, A. A.; Trunov, I. T.; Sarychev, V. I.
2017-10-01
The paper presents the method of calculation of the combined frame and roof bolting. Recommendations on providing joint operation of roof bolting with steel support frames are given. Graphs for determining standard rock movement, as well as for defining proof load on the yielding support, were developed.
Improving Neutron Kinetics and Thermal Hydraulics coupled tools for BEPU calculations
Energy Technology Data Exchange (ETDEWEB)
Pericas, R.; Reventós, F.; Batet, Il.
2015-07-01
The BEPU methodology is capable of providing a solution in terms of increasing the nuclear power production without compromising the safety margins. This study presents different improvements performed using tools available at UPC in the field of Neutron Kinetics and Thermal Hydraulics coupled systems. The paper describes a comparison between the BEPU methodology and the Conservative Bounding methodology within the framework of the Neutron Kinetics and Thermal Hydraulics coupled systems. To perform such comparison the following tools have been selected: TRACE for thermal-hydraulic system calculations, PARCS for reactor kinetics core simulator code. A Main Steam Line Break (MSLB) in a Pressurized Water Reactor (PWR) is the selected simulated transient to show the improvements performed. (Author)
Brito, Paula; Antunes, Fernando
2014-10-01
The lack of kinetic data concerning the biological effects of reactive oxygen species is slowing down the development of the field of redox signaling. Herein, we deduced and applied equations to estimate kinetic parameters from typical redox signaling experiments. H2O2-sensing mediated by the oxidation of a protein target and the switch-off of this sensor, by being converted back to its reduced form, are the two processes for which kinetic parameters are determined. The experimental data required to apply the equations deduced is the fraction of the H2O2 sensor protein in the reduced or in the oxidized state measured in intact cells or living tissues after exposure to either endogenous or added H2O2. Either non-linear fittings that do not need transformation of the experimental data or linearized plots in which deviations from the equations are easily observed can be used. The equations were shown to be valid by fitting to them virtual time courses simulated with a kinetic model. The good agreement between the kinetic parameters estimated in these fittings and those used to simulate the virtual time courses supported the accuracy of the kinetic equations deduced. Finally, equations were successfully tested with real data taken from published experiments that describe redox signaling mediated by the oxidation of two protein tyrosine phosphatases, PTP1B and SHP-2, which are two of the few H2O2-sensing proteins with known kinetic parameters. Whereas for PTP1B estimated kinetic parameters fitted in general the present knowledge, for SHP-2 results obtained suggest that reactivity towards H2O2 as well as the rate of SHP-2 regeneration back to its reduced form are higher than previously thought. In conclusion, valuable quantitative kinetic data can be estimated from typical redox signaling experiments, thus improving our understanding about the complex processes that underline the interplay between oxidative stress and redox signaling responses.
Estimation of kinetic and thermodynamic ligand-binding parameters using computational strategies.
Deganutti, Giuseppe; Moro, Stefano
2017-04-01
Kinetic and thermodynamic ligand-protein binding parameters are gaining growing importance as key information to consider in drug discovery. The determination of the molecular structures, using particularly x-ray and NMR techniques, is crucial for understanding how a ligand recognizes its target in the final binding complex. However, for a better understanding of the recognition processes, experimental studies of ligand-protein interactions are needed. Even though several techniques can be used to investigate both thermodynamic and kinetic profiles for a ligand-protein complex, these procedures are very often laborious, time consuming and expensive. In the last 10 years, computational approaches have enormous potential in providing insights into each of the above effects and in parsing their contributions to the changes in both kinetic and thermodynamic binding parameters. The main purpose of this review is to summarize the state of the art of computational strategies for estimating the kinetic and thermodynamic parameters of a ligand-protein binding.
Atomic Calculations with a One-Parameter, Single Integral Method.
Baretty, Reinaldo; Garcia, Carmelo
1989-01-01
Presents an energy function E(p) containing a single integral and one variational parameter, alpha. Represents all two-electron integrals within the local density approximation as a single integral. Identifies this as a simple treatment for use in an introductory quantum mechanics course. (MVL)
Correlating thermodynamic and kinetic parameters with amorphous stability
DEFF Research Database (Denmark)
Graeser, Kirsten A; Patterson, James E; Zeitler, J Axel
2009-01-01
stability of amorphous drugs for a larger sample set (12 drugs). The relaxation time, fragility index and configurational thermodynamic properties (enthalpy, entropy and Gibbs free energy) were calculated and correlated to the actual stability behaviour, obtained for 12 drugs. Below the glass transition...... temperature the relaxation time and fragility showed no correlation with the observed physical stability. All drugs were calculated to be 'fragile'. However, variation in the fragility index existed, with values spanning from 8.9 to 21.3, manifesting themselves as differences in the temperature dependencies...
Directory of Open Access Journals (Sweden)
Gharby Said
2016-07-01
Full Text Available The aim of the present investigation is to compare the chemical characterization of four monovarietal virgin olive oils obtained from fruits of olive trees grown in Morocco (Picholine, Picual, Arebiquine, Koroneiki with kinetic parameters of oxidation based on Rancimat measurements and finally to assess the oxidative stabilities. The examined oils from different varieties showed a chemical composition within the regulatory limits. Rancimat measurements of induction times were carried out under isothermal conditions in an air atmosphere at temperatures from 373 to 423 K with intervals of 10 K. Using the Arrhenius-type correlation between the inverse induction times and the absolute temperature of the measurements, Ea, Z, and k values for oil oxidation under Rancimat conditions were calculated. The primary kinetic parameters derived from this method were qualitatively consistent and help to evaluate the oxidative stabilities of oils at increased temperatures.
Calculation of trajectory parameters of long pass in basketball.
Directory of Open Access Journals (Sweden)
Charikova K.M.
2011-08-01
Full Text Available Values of a ball's flight trajectory parameters depending on a distance of long pass, a corner of a ball's start and height of a throwing point are submitted in article. Coordinates of reference points installation for training to long pass with an optimum trajectory of a ball's flight are designed. Requirements to simulators design are determined. Corners of ball's long pass performance in various game situations are recommended.
Automated placement of interfaces in conformational kinetics calculations using machine learning
Grazioli, Gianmarc; Butts, Carter T.; Andricioaei, Ioan
2017-10-01
Several recent implementations of algorithms for sampling reaction pathways employ a strategy for placing interfaces or milestones across the reaction coordinate manifold. Interfaces can be introduced such that the full feature space describing the dynamics of a macromolecule is divided into Voronoi (or other) cells, and the global kinetics of the molecular motions can be calculated from the set of fluxes through the interfaces between the cells. Although some methods of this type are exact for an arbitrary set of cells, in practice, the calculations will converge fastest when the interfaces are placed in regions where they can best capture transitions between configurations corresponding to local minima. The aim of this paper is to introduce a fully automated machine-learning algorithm for defining a set of cells for use in kinetic sampling methodologies based on subdividing the dynamical feature space; the algorithm requires no intuition about the system or input from the user and scales to high-dimensional systems.
Calculation of Grounding Grids Parameter at Arbitrary Geometry
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Carlos L. B. Silva
2017-06-01
Full Text Available This paper deals with the computation of ground resistance, surface voltage, touch voltage and step voltage, to mesh with horizontal wires arranged in different angles. The computer program implemented used in the mathematical modeling is based on the method proposed by Heppe, which allows obtaining the grounding parameters for homogeneous soil and soil stratified in two layers. The results obtained with the proposed method will be compared with other methods in literature. Also will be presented the results of a grounding grid using wires at various angles.
Three-dimensional Monte Carlo calculation of some nuclear parameters
Günay, Mehtap; Şeker, Gökmen
2017-09-01
In this study, a fusion-fission hybrid reactor system was designed by using 9Cr2WVTa Ferritic steel structural material and the molten salt-heavy metal mixtures 99-95% Li20Sn80 + 1-5% RG-Pu, 99-95% Li20Sn80 + 1-5% RG-PuF4, and 99-95% Li20Sn80 + 1-5% RG-PuO2, as fluids. The fluids were used in the liquid first wall, blanket and shield zones of a fusion-fission hybrid reactor system. Beryllium (Be) zone with the width of 3 cm was used for the neutron multiplication between the liquid first wall and blanket. This study analyzes the nuclear parameters such as tritium breeding ratio (TBR), energy multiplication factor (M), heat deposition rate, fission reaction rate in liquid first wall, blanket and shield zones and investigates effects of reactor grade Pu content in the designed system on these nuclear parameters. Three-dimensional analyses were performed by using the Monte Carlo code MCNPX-2.7.0 and nuclear data library ENDF/B-VII.0.
Energy Technology Data Exchange (ETDEWEB)
Li, X.Q.; Xiao, X.F.; Mi, J.K.; Tang, Y.H.; Xiao, Z.Y.; Liu, D.; Shen, J.G.; Yang, Y.F.; Wang, Y.; Dong, P. [Chinese Academy of Sciences, Ghangzhou (China)
2008-02-15
In a thermal simulation experiment of gold tubes of closed-system, calculating with the KINETICS and GOR-ISOTOPE KINETICS software, kinetic parameters of gas generation and methane carbon isotopic fractionation from Triassic-Jurassic hydrocarbon source rocks in the Kuqa depression of Tarim Basin are obtained. The activation energies of methane generated from Jurassic coal, Jurassic mudstone and Triassic mudstone in the Kuqa Depression are 197-268 kJ/mol, 180-260 kJ/mol and 214-289 kJ/mol, respectively, and their frequency factors are 5.265x10{sup 13} s{sup -1}, 9.761x10{sup 11} s{sup -1} and 2.270 x 1014 s{sup -1}. This reflects their differences of hydrocarbon generation behaviors. The kinetic parameters of methane carbon isotopic fractionation are also different in Jurassic coal, Jurassic mudstone and Triassic mudstone, whose average activation energies are 228 kJ/mol, 205 kJ/mol and 231 kJ/mol, respectively. Combined with the geological background, the origin of natural gas in the Yinan-2 gas pool is discussed, and an accumulation model of natural gas is thus established. The Yinan-2 gas is primarily derived from Jurassic coal-bearing source rocks in the Yangxia Sag. Main gas accumulation time is 5-0 Ma and the corresponding Ro is in the range from 1.25%-1.95%. The loss rate of natural gas is 25%-30%.
Tang, Zhiye; Chang, Chia-En A
2018-01-09
Understanding the fine balance between changes of entropy and enthalpy and the competition between a guest and water molecules in molecular binding is crucial in fundamental studies and practical applications. Experiments provide measurements. However, illustrating the binding/unbinding processes gives a complete picture of molecular recognition not directly available from experiments, and computational methods bridge the gaps. Here, we investigated guest association/dissociation with β-cyclodextrin (β-CD) by using microsecond-time-scale molecular dynamics (MD) simulations, postanalysis and numerical calculations. We computed association and dissociation rate constants, enthalpy, and solvent and solute entropy of binding. All the computed values of kon, koff, ΔH, ΔS, and ΔG using GAFF-CD and q4MD-CD force fields for β-CD could be compared with experimental data directly and agreed reasonably with experiment findings. In addition, our study further interprets experiments. Both force fields resulted in similar computed ΔG from independently computed kinetics rates, ΔG = -RT ln(kon·C0/koff), and thermodynamics properties, ΔG = ΔH - TΔS. The water entropy calculations show that the entropy gain of desolvating water molecules are a major driving force, and both force fields have the same strength of nonpolar attractions between solutes and β-CD as well. Water molecules play a crucial role in guest binding to β-CD. However, collective water/β-CD motions could contribute to different computed kon and ΔH values by different force fields, mainly because the parameters of β-CD provide different motions of β-CD, hydrogen-bond networks of water molecules in the cavity of free β-CD, and strength of desolvation penalty. As a result, q4MD-CD suggests that guest binding is mostly driven by enthalpy, while GAFF-CD shows that gaining entropy is the major driving force of binding. The study deepens our understanding of ligand-receptor recognition and suggests
Recommended environmental dose calculation methods and Hanford-specific parameters
Energy Technology Data Exchange (ETDEWEB)
Schreckhise, R.G.; Rhoads, K.; Napier, B.A.; Ramsdell, J.V. (Pacific Northwest Lab., Richland, WA (United States)); Davis, J.S. (Westinghouse Hanford Co., Richland, WA (United States))
1993-03-01
This document was developed to support the Hanford Environmental Dose overview Panel (HEDOP). The Panel is responsible for reviewing all assessments of potential doses received by humans and other biota resulting from the actual or possible environmental releases of radioactive and other hazardous materials from facilities and/or operations belonging to the US Department of Energy on the Hanford Site in south-central Washington. This document serves as a guide to be used for developing estimates of potential radiation doses, or other measures of risk or health impacts, to people and other biota in the environs on and around the Hanford Site. It provides information to develop technically sound estimates of exposure (i.e., potential or actual) to humans or other biotic receptors that could result from the environmental transport of potentially harmful materials that have been, or could be, released from Hanford operations or facilities. Parameter values and information that are specific to the Hanford environs as well as other supporting material are included in this document.
Energy Technology Data Exchange (ETDEWEB)
Pavlovitchev, A.M.
2000-03-08
The present work is a part of Joint U.S./Russian Project with Weapons-Grade Plutonium Disposition in VVER Reactor and presents the neutronics calculations of kinetics parameters of VVER-1000 core with 3 introduced MOX LTAs. MOX LTA design has been studied in [1] for two options of MOX LTA: 100% plutonium and of ''island'' type. As a result, zoning i.e. fissile plutonium enrichments in different plutonium zones, has been defined. VVER-1000 core with 3 introduced MOX LTAs of chosen design has been calculated in [2]. In present work, the neutronics data for transient analysis codes (RELAP [3]) has been obtained using the codes chain of RRC ''Kurchatov Institute'' [5] that is to be used for exploitation neutronics calculations of VVER. Nowadays the 3D assembly-by-assembly code BIPR-7A and 2D pin-by-pin code PERMAK-A, both with the neutronics constants prepared by the cell code TVS-M, are the base elements of this chain. It should be reminded that in [6] TVS-M was used only for the constants calculations of MOX FAs. In current calculations the code TVS-M has been used both for UOX and MOX fuel constants. Besides, the volume of presented information has been increased and additional explications have been included. The results for the reference uranium core [4] are presented in Chapter 2. The results for the core with 3 MOX LTAs are presented in Chapter 3. The conservatism that is connected with neutronics parameters and that must be taken into account during transient analysis calculations, is discussed in Chapter 4. The conservative parameters values are considered to be used in 1-point core kinetics models of accident analysis codes.
Closed-Form Formulas for Estimation of Kinetic Parameters in One- and Two-Compartment Models
Energy Technology Data Exchange (ETDEWEB)
Zeng, Gengsheng [Univ. of Utah, Salt Lake City, UT (United States); Kadrmas, Dan [Univ. of Utah, Salt Lake City, UT (United States); Gullberg, Grant [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2011-05-24
.Nowadays the most reliable approach to estimate the kinetic parameters is to minimize an objective function which is essentially the distance between the measured data and the model generated pseudo data. Due to the highly non-linear nature of the model, common optimization algorithms usually fail to find the true minimum. A brute-force search method sometimes must be used to find the true minimum. This paper attempts to use the Laplace transform and Z-transform methods to derive closed-form formulas for kinetic parameter estimation problems, which assume one- or two-compartment models. The proposed method is computationally efficient and its solution is unique. When data sampling interval is small, the proposed method is able to accurately estimate the kinetic parameter; when the interval is larger, the proposed method fails to give a meaningful estimate. The one-compartment method is more robust than the two-compartment method.
Reaction Kinetic Parameters and Surface Thermodynamic Properties of Cu2O Nanocubes
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Xingxing Li
2015-07-01
Full Text Available Cuprous oxide (Cu2O nanocubes were synthesized by reducing Cu(OH2 in the presence of sodium citrate at room temperature. The samples were characterized in detail by field-emission scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray powder diffraction, and N2 absorption (BET specific surface area. The equations for acquiring reaction kinetic parameters and surface thermodynamic properties of Cu2O nanocubes were deduced by establishment of the relations between thermodynamic functions of Cu2O nanocubes and these of the bulk Cu2O. Combined with thermochemical cycle, transition state theory, basic theory of chemical thermodynamics, and in situ microcalorimetry, reaction kinetic parameters, specific surface enthalpy, specific surface Gibbs free energy, and specific surface entropy of Cu2O nanocubes were successfully determined. We also introduced a universal route for gaining reaction kinetic parameters and surface thermodynamic properties of nanomaterials.
Fuzzy Stochastic Petri Nets for Modeling Biological Systems with Uncertain Kinetic Parameters.
Liu, Fei; Heiner, Monika; Yang, Ming
2016-01-01
Stochastic Petri nets (SPNs) have been widely used to model randomness which is an inherent feature of biological systems. However, for many biological systems, some kinetic parameters may be uncertain due to incomplete, vague or missing kinetic data (often called fuzzy uncertainty), or naturally vary, e.g., between different individuals, experimental conditions, etc. (often called variability), which has prevented a wider application of SPNs that require accurate parameters. Considering the strength of fuzzy sets to deal with uncertain information, we apply a specific type of stochastic Petri nets, fuzzy stochastic Petri nets (FSPNs), to model and analyze biological systems with uncertain kinetic parameters. FSPNs combine SPNs and fuzzy sets, thereby taking into account both randomness and fuzziness of biological systems. For a biological system, SPNs model the randomness, while fuzzy sets model kinetic parameters with fuzzy uncertainty or variability by associating each parameter with a fuzzy number instead of a crisp real value. We introduce a simulation-based analysis method for FSPNs to explore the uncertainties of outputs resulting from the uncertainties associated with input parameters, which works equally well for bounded and unbounded models. We illustrate our approach using a yeast polarization model having an infinite state space, which shows the appropriateness of FSPNs in combination with simulation-based analysis for modeling and analyzing biological systems with uncertain information.
EQUILIBRIUM AND KINETIC PARAMETERS FOR THE SEDIMENTATION OF TARTARIC SALTS IN YOUNG WINES
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Ecaterina Covaci
2015-06-01
Full Text Available In young wines potassium hydrogen tartrate is always present in supersaturating concentration and crystallizes spontaneously. The aim of this study is to obtain kinetic parameters, which explain the stability of young wines during the stabilization treatments. The kinetic and equilibrium parameters were evaluated and discussed. The heating factor has a decisive influence on the reaction rate of potassium hydrogen tartrate precipitation in young wines. An increase of temperature leads to a decrease in efficiency of stabilization process and to an enhancement of the activation energy of the system. According to the obtained experimental results, the optimal regime for production and stabilization of young wines has been established.
DEFF Research Database (Denmark)
Sayar, N.A.; Chen, B.H.; Lye, G.J.
2009-01-01
In this paper we have used a proposed mathematical model, describing the carbon-carbon bond format ion reaction between beta-hydroxypyruvate and glycolaldehyde to synthesise L-erythrulose, catalysed by the enzyme transketolase, for the analysis of the sensitivity of the process to its kinetic...... parameters. The model was validated with experimental data. As a conclusion, kinetic parameters with a possible positive impact on reaction performance were identified and assessed in relation to operating conditions. This resulted in the identification of suitable catalyst and process development targets...
Directory of Open Access Journals (Sweden)
Zaanoun, I.
2014-09-01
Full Text Available The present study investigated the Kinetic parameter determination of edible argan oil (coldpressed from roasted argan kernels and cosmetic argan oil (cold-pressed from unroasted argan kernels under the Rancimat test conditions. The physicochemical parameters of edible and cosmetic argan oil immediately after preparation and after accelerated oxidation test Rancimat at different temperatures 90 °C, 100 °C, 110 °C, 120 °C, 130 °C and 140 °C were determined and compared. The natural logarithms of the kinetic rate constant (kvalue varied linearly with respect to temperature. An increasing rate of oxidation could be observed as temperature increased. On the basis of the Arrhenius equation and the activated complex theory, frequency factors A, activation energies Ea, Q10 numbers, activation enthalpies ΔH, and activation entropies ΔS for oxidative stability of the vegetable oils were calculated. The accelerated oxidation and Kinetic parameters have shown that edible argan oil can be stored much better than cosmetic oil.En presente estudio se determinaron los parámetros cinéticosde aceites de argán comestible (prensado en frío a partir de granos tostados de argán y cosmético (prensado en frío a partir de granos de argán sin tostar bajo las condiciones del método Rancimat. Se determinó y comparó los parámetros físico-químicos de aceites de argán comestible y cosmético inmediatamente después de la preparación y después de la oxidación acelerada mediante Rancimat a temperaturas de 90 °C, 100 °C, 110 °C, 120 °C, 130 °C y 140 °C Los logaritmos naturales de la constante de velocidad cinética (valor k variaron linealmente con respecto a la temperatura. Se pudo observar un valor creciente de la oxidación conel aumento de la temperatura. Se calculó para la estabilidad oxidativa de los aceites vegetalesy sobre la base de la ecuación de Arrhenius y la teoría del complejo activado, la frecuencia de los factores A, energ
Directory of Open Access Journals (Sweden)
Hang Liu
2017-05-01
Full Text Available Although traditional fault diagnosis methods can qualitatively identify the failure modes for power equipment, it is difficult to evaluate the failure probability quantitatively. In this paper, a failure probability calculation method for power equipment based on multi-characteristic parameters is proposed. After collecting the historical data of different fault characteristic parameters, the distribution functions and the cumulative distribution functions of each parameter, which are applied to dispersing the parameters and calculating the differential warning values, are calculated by using the two-parameter Weibull model. To calculate the membership functions of parameters for each failure mode, the Apriori algorithm is chosen to mine the association rules between parameters and failure modes. After that, the failure probability of each failure mode is obtained by integrating the membership functions of different parameters by a weighted method, and the important weight of each parameter is calculated by the differential warning values. According to the failure probability calculation result, the series model is established to estimate the failure probability of the equipment. Finally, an application example for two 220 kV transformers is presented to show the detailed process of the method. Compared with traditional fault diagnosis methods, the calculation results not only identify the failure modes correctly, but also reflect the failure probability changing trend of the equipment accurately.
Hughes, D. L.; Ray, R. J.; Walton, J. T.
1985-01-01
The calculated value of net thrust of an aircraft powered by a General Electric F404-GE-400 afterburning turbofan engine was evaluated for its sensitivity to various input parameters. The effects of a 1.0-percent change in each input parameter on the calculated value of net thrust with two calculation methods are compared. This paper presents the results of these comparisons and also gives the estimated accuracy of the overall net thrust calculation as determined from the influence coefficients and estimated parameter measurement accuracies.
Kinetic Parameters of Thermal Decomposition Process Analyzed using a Mathematical Model
Nandiyanto, A. B. D.; Ekawati, R.; Wibawa, S. C.
2018-01-01
The purpose of this study was to show a mathematical analysis model for understanding kinetic parameters of thermal decomposition process. The mathematical model was derived based on phenomena happen during the thermal-related reaction. To get the kinetic parameters (i.e. reaction order, activation energy, and Arrhenius constant), the model was combined with the thermal characteristics of material gained from the thermal gravity (TG) and differential thermal analysis (DTA) curves. As an example, the model was used for analyzing the kinetic properties of trinitrotoluene. Interestingly, identical results gained from the present model with current literatures were obtained; in which these were because the present model was derived directly from the analysis of stoichiometrical and thermal analysis of the ideal chemical reaction. Since the present model confirmed to have a good agreement with current theories, further derivation from the present mathematical model can be useful for further development.
Liu, H.; Yu, D.; Jiang, Y.; Sun, X.
2009-06-01
This paper characterizes holographic scattering and demonstrates its application in determining the kinetic parameters in materials with high transmittance and strong holographic scattering like phenanthrenequinone doped poly (methyl methacrylate) (PQ-PMMA). We define a polymerization rate parameter which can be determined by the temporal evolution of the scattering losses. Two basic kinetic parameters, quantum yield and molar-absorption coefficient, are obtained by nonlinear fitting the curve of the polymerization rate parameter as a function of the thickness, which are 1.9×10-6 mol/einstein and 2.1×104 cm2/mol for a wavelength of 532 nm respectively. These results improve the understanding of photochemical behaviors and allow us to describe the grating formation in the photopolymer reasonably.
Element-specific and constant parameters used for dose calculations in SR-Site
Energy Technology Data Exchange (ETDEWEB)
Norden, Sara (Svensk Kaernbraenslehantering AB (Sweden)); Avila, Rodolfo; De la Cruz, Idalmis; Stenberg, Kristofer; Grolander, Sara (Facilia AB (Sweden))
2010-12-15
The report presents Best Estimate (BE) values and Probability Distribution Functions (PDFs) of Concentration Ratios (CR) for different types of terrestrial and aquatic biota and distribution coefficients (K{sub d}) for organic and inorganic deposits, as well as for suspended matter in freshwater and marine ecosystems. The BE values have been used in deterministic simulations for derivation of Landscape Dose Factors (LDF) applied for dose assessments in SR-Site. The PDFs have been used in probabilistic simulations for uncertainty and sensitivity analysis of the LDFs. The derivation of LDFs for SR-Site is described in /Avila et al. 2010/. The CR and K{sub d} values have been derived using both site-specific data measured at Laxemar and Forsmark during the site investigation program and literature data. These two data sources have been combined using Bayesian updating methods, which are described in detail in an Appendix, along with the input data used in the statistical analyses and the results obtained. The report also describes a kinetic-allometric model that was applied for deriving values of CR for terrestrial herbivores in cases when site and literature data for an element were missing. In addition, the report presents values for a number of other parameters used in the SR-Site Radionuclide Model for the biosphere: radionuclide decay-ingrowth data, elemental diffusivities, fractions of element content released during decomposition processes, ingestion of food, water and soil by cattle, elements retention fraction on plant surfaces during irrigation. The report also presents parameter values used in calculation of doses to a reference man: dose coefficients for inhalation, ingestion and external exposure, inhalation rates, ingestion rates of food and water
Hardee, John R.; Delgado, Bryan; Jones, Wray
2011-01-01
The kinetic parameters for the conversion of alpha-D-glucose to beta-D-glucose were measured using a blood glucometer. The reaction order, rate constant, and Arrhenius activation energy are reported for the noncatalyzed reaction and turnover number and Michaelis constant are reported for the reaction catalyzed by porcine kidney mutarotase. The…
Dynamic identification of growth and survival kinetic parameters of microorganisms in foods
Inverse analysis is a mathematical method used in predictive microbiology to determine the kinetic parameters of microbial growth and survival in foods. The traditional approach in inverse analysis relies on isothermal experiments that are time-consuming and labor-intensive, and errors are accumula...
Heterogeneity of kinetic parameters of enzymes in situ in rat liver lobules
van Noorden, C. J.; Jonges, G. N.
1995-01-01
In the present review, metabolic compartmentation in liver lobules is discussed as being dynamic and more complex than thus far assumed on the basis of numbers of mRNA or protein molecules or the capacity (zero-order activity) of enzymes. Isoenzyme distribution patterns and local kinetic parameters
Effects of reaction-kinetic parameters on modeling reaction pathways in GaN MOVPE growth
Zhang, Hong; Zuo, Ran; Zhang, Guoyi
2017-11-01
In the modeling of the reaction-transport process in GaN MOVPE growth, the selections of kinetic parameters (activation energy Ea and pre-exponential factor A) for gas reactions are quite uncertain, which cause uncertainties in both gas reaction path and growth rate. In this study, numerical modeling of the reaction-transport process for GaN MOVPE growth in a vertical rotating disk reactor is conducted with varying kinetic parameters for main reaction paths. By comparisons of the molar concentrations of major Ga-containing species and the growth rates, the effects of kinetic parameters on gas reaction paths are determined. The results show that, depending on the values of the kinetic parameters, the gas reaction path may be dominated either by adduct/amide formation path, or by TMG pyrolysis path, or by both. Although the reaction path varies with different kinetic parameters, the predicted growth rates change only slightly because the total transport rate of Ga-containing species to the substrate changes slightly with reaction paths. This explains why previous authors using different chemical models predicted growth rates close to the experiment values. By varying the pre-exponential factor for the amide trimerization, it is found that the more trimers are formed, the lower the growth rates are than the experimental value, which indicates that trimers are poor growth precursors, because of thermal diffusion effect caused by high temperature gradient. The effective order for the contribution of major species to growth rate is found as: pyrolysis species > amides > trimers. The study also shows that radical reactions have little effect on gas reaction path because of the generation and depletion of H radicals in the chain reactions when NH2 is considered as the end species.
Rogers, Michael A; Marangoni, Alejandro G
2016-12-06
Changes in solvent chemistry influenced kinetics of both nucleation and crystallization of 12-hydroxyoctadecenoic, as determined using differential scanning calorimetry and applying a modified Avrami model to the calorimetric data. Altering solvent properties influenced solvent-gelator compatibility, which in turn altered the chemical potential of the system at the onset of crystallization, the kinetics of gelation, and the resulting 12HOA crystal fiber length. The chemical potential at the onset of crystallization was linearly correlated to both the hydrogen-bonding Hansen solubility parameter and the solvent-gelator vectorial distance in Hansen space, Ra. Our work suggests that solvent properties can be modulated to affect the solubility of 12HOA, which in turn influences the kinetics of crystallization and the self-assembly of this organogelator into supramolecular crystalline structures. Therefore, modulation of solvent properties during organogelation can be used to control fiber length and thus engineer the physical properties of the gel.
Hamborg, Espen S.; Versteeg, Geert F.
2012-01-01
The forward and reverse kinetic rate parameters have been determined for CO2 absorption and desorption mass transfer processes in aqueous 2.0 M MDEA solutions at temperatures of 298.15, 313.15, and 333.15 K and the loading of CO2 ranging from 0 to 0.8. The derived kinetic rate parameters have been
Thermoluminescence systems with two or more glow peaks described by anomalous kinetic parameters
Energy Technology Data Exchange (ETDEWEB)
Levy, P.W.
1983-01-01
The usual first and second order TL kinetic expressions are based on a number of assumptions, including the usually unstated assumption that charges released from one type of trap, giving rise to one glow peak, are not retrapped on other types of traps, associated with other glow peaks. Equations have been developed describing TL systems in which charges released from one type of trap may be retrapped in other types of traps. Called interactive kinetic equations, they are quite simple but have been studied by numerical methods. In particular, glow curves computed from the interactive kinetic equations have been regarded as data and analyzed by fitting them to the usual first and second order kinetic expressions. All of the anomalous features described above are reproduced. For example, usually the computed glow peaks are well fitted by the first and second order expressions over their upper 60 to 80% but not in the wings. This explains why the usual analysis methods, especially those utilizing peak temperature, full width, etc. appear to describe such peaks. Often unrealistic kinetic parameters are often obtained. Furthermore, the computed glow curves often reproduce the observed dependence on dose.
Improvement of calculation method for electrical parameters of short network of ore-thermal furnaces
Aliferov, A. I.; Bikeev, R. A.; Goreva, L. P.
2017-10-01
The paper describes a new calculation method for active and inductive resistance of split interleaved current leads packages in ore-thermal electric furnaces. The method is developed on basis of regression analysis of dependencies of active and inductive resistances of the packages on their geometrical parameters, mutual disposition and interleaving pattern. These multi-parametric calculations have been performed with ANSYS software. The proposed method allows solving split current lead electrical parameters minimization and balancing problems for ore-thermal furnaces.
Kinetics analysis and quantitative calculations for the successive radioactive decay process
Zhou, Zhiping; Yan, Deyue; Zhao, Yuliang; Chai, Zhifang
2015-01-01
The general radioactive decay kinetics equations with branching were developed and the analytical solutions were derived by Laplace transform method. The time dependence of all the nuclide concentrations can be easily obtained by applying the equations to any known radioactive decay series. Taking the example of thorium radioactive decay series, the concentration evolution over time of various nuclide members in the family has been given by the quantitative numerical calculations with a computer. The method can be applied to the quantitative prediction and analysis for the daughter nuclides in the successive decay with branching of the complicated radioactive processes, such as the natural radioactive decay series, nuclear reactor, nuclear waste disposal, nuclear spallation, synthesis and identification of superheavy nuclides, radioactive ion beam physics and chemistry, etc.
Application of toxico-kinetic criteria as a basis for toxicometric parameters.
Ulanova, I P; Avilova, G G
1987-01-01
In an experiment with single exposure to benzene and styrene at a level corresponding, to the threshold of harmful effect established by functional indices the intensity of metabolism was found to decrease. Toxico-kinetic characteristics of the substance in a single experiment permit us to prognosticate the risk of developing chronic intoxication. In comparison with indices characterizing general state of the organism, toxicokinetic indices enhance the reliability of toxicometric parameters used in determining Mac's for the air of the working area.
Arbuscular mycorrhiza and kinetic parameters of phosphorus absorption by bean plants
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Silveira Adriana Parada Dias da
2004-01-01
Full Text Available The mechanisms that determine greater P absorption by mycorrhizal plants are still not completely clear, and are attributed, in part, to an increase in the number of absorption sites promoted by the hyphae, and/or to a greater affinity of the colonized hypha or root carriers to P. The effect of mycorrhizae formed by Glomus etunicatum on the kinetic parameters of P absorption by the roots and on P influx in bean plants of the IAC-Carioca cultivar was evaluated, in two distinct plant development periods: at the onset of flowering and at the pod-filling stage (35 and 50 days after sowing, respectively. A mixture of sand and silica (9:1 was utilized as substrate and irrigated with nutrient solution. The kinetics assay was performed by the method of 32P depletion from the solution (depletion curve, using intact plants. Mycorrhization promoted greater growth and P absorption by bean plants, which was more conspicuously observed at the pod-filling stage. Mycorrhizal plants showed higher values of maximum ion uptake rate (Vmax and net P influx at the flowering stage. Lower minimum ion concentration (Cmin and Michaelis-Menten constant (Km values were verified in mycorrhizal plants at the pod-filling stage. Mycorrhizal plants also presented higher net P influx per plant, in both stages. Cmin was the kinetic parameter more intimately related to P absorption, and a significant correlation was obtained between this parameter and shoot P content and accumulation in bean plants.
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Passalia, Claudio; Alfano, Orlando M. [INTEC - Instituto de Desarrollo Tecnologico para la Industria Quimica, CONICET - UNL, Gueemes 3450, 3000 Santa Fe (Argentina); FICH - Departamento de Medio Ambiente, Facultad de Ingenieria y Ciencias Hidricas, Universidad Nacional del Litoral, Ciudad Universitaria, 3000 Santa Fe (Argentina); Brandi, Rodolfo J., E-mail: rbrandi@santafe-conicet.gov.ar [INTEC - Instituto de Desarrollo Tecnologico para la Industria Quimica, CONICET - UNL, Gueemes 3450, 3000 Santa Fe (Argentina); FICH - Departamento de Medio Ambiente, Facultad de Ingenieria y Ciencias Hidricas, Universidad Nacional del Litoral, Ciudad Universitaria, 3000 Santa Fe (Argentina)
2012-04-15
Highlights: Black-Right-Pointing-Pointer Indoor pollution control via photocatalytic reactors. Black-Right-Pointing-Pointer Scaling-up methodology based on previously determined mechanistic kinetics. Black-Right-Pointing-Pointer Radiation interchange model between catalytic walls using configuration factors. Black-Right-Pointing-Pointer Modeling and experimental validation of a complex geometry photocatalytic reactor. - Abstract: A methodology for modeling photocatalytic reactors for their application in indoor air pollution control is carried out. The methodology implies, firstly, the determination of intrinsic reaction kinetics for the removal of formaldehyde. This is achieved by means of a simple geometry, continuous reactor operating under kinetic control regime and steady state. The kinetic parameters were estimated from experimental data by means of a nonlinear optimization algorithm. The second step was the application of the obtained kinetic parameters to a very different photoreactor configuration. In this case, the reactor is a corrugated wall type using nanosize TiO{sub 2} as catalyst irradiated by UV lamps that provided a spatially uniform radiation field. The radiative transfer within the reactor was modeled through a superficial emission model for the lamps, the ray tracing method and the computation of view factors. The velocity and concentration fields were evaluated by means of a commercial CFD tool (Fluent 12) where the radiation model was introduced externally. The results of the model were compared experimentally in a corrugated wall, bench scale reactor constructed in the laboratory. The overall pollutant conversion showed good agreement between model predictions and experiments, with a root mean square error less than 4%.
Gunasundari, Elumalai; Senthil Kumar, Ponnusamy
2017-04-01
This study discusses about the biosorption of Cr(VI) ion from aqueous solution using ultrasonic assisted Spirulina platensis (UASP). The prepared UASP biosorbent was characterised by Fourier transform infrared spectroscopy, X-ray diffraction, Brunauer-Emmet-Teller, scanning electron spectroscopy and energy dispersive X-ray and thermogravimetric analyses. The optimum condition for the maximum removal of Cr(VI) ions for an initial concentration of 50 mg/l by UASP was measured as: adsorbent dose of 1 g/l, pH of 3.0, contact time of 30 min and temperature of 303 K. Adsorption isotherm, kinetics and thermodynamic parameters were calculated. Freundlich model provided the best results for the removal of Cr(VI) ions by UASP. The adsorption kinetics of Cr(VI) ions onto UASP showed that the pseudo-first-order model was well in line with the experimental data. In the thermodynamic study, the parameters like Gibb's free energy, enthalpy and entropy changes were evaluated. This result explains that the adsorption of Cr(VI) ions onto the UASP was exothermic and spontaneous in nature. Desorption of the biosorbent was done using different desorbing agents in which NaOH gave the best result. The prepared material showed higher affinity for the removal of Cr(VI) ions and this may be an alternative material to the existing commercial adsorbents.
How is the Monoclonal Antibodies Kinetic Affected by Changes of Their Physical Parameters?
Delgado-Correal, Camilo; Lizarazo-Pérez, Heidy Alexandra
2010-01-01
The study of monoclonal antibodies (MAb) is a field of great interest to science medicine, for example, anti-TNF agents (infliximab and adalimumab) represent an important tool for the management of autoimmune and inflammatory disorders. In this work we focus on the physical description of the transport kinetics of MAb in a fluid with laminar flow and parabolic profile. To simulate the kinetics of the MAb, standard equations were solved numerically (using The Verlet algorithm) to calculate the motion of a particle with a spherically symmetric inside of parabolic laminar flow, in order to find the time evolution of the antibody velocity in blood plasma in function of the increase of the radius, mass and density of the MAb, and the fluid pressure in blood vessels. In the case of we fixed the value of the antibody density, their kinetics increased when the pressure in the vessels increased. When we fixed the pressure in the vessels we found: if we reduce the antibody radius their kinetics increased, and when we i...
Calculation of line parameters of the ν3 band of monodeuterated methane: Nitrogen broadening
Lavrentieva, N. N.; Dudaryonok, A. S.; Buldyreva, J. V.
2017-09-01
Halfwidths and shifts of CH3D lines are calculated for the case of nitrogen broadening. The calculations are performed for room temperature (296 K) for vibrational-rotational lines in the ν3 parallel band, with the rotational quantum numbers varying in the ranges of 0 ≤ J ≤ 70 and 0 ≤ K ≤ 20. For each line, the temperature-dependence characteristics are calculated in the range of 200-400 K recommended for the HITRAN database. The calculations are carried out using a semiempirical method with a correction factor the parameters of which are adjusted on a number of experimental values.
EMF signals and ion/ligand binding kinetics: prediction of bioeffective waveform parameters.
Pilla, A A; Muehsam, D J; Markov, M S; Sisken, B F
1999-02-01
The kinetics of an electromagnetic field (EMF) target pathway are used to estimate frequency windows for EMF bioeffects. Ion/ligand binding is characterized via first order kinetics from which a specific electrical impedance can be derived. The resistance/capacitance properties of the binding pathway impedance, determined by the kinetics of the rate-determining step, define the frequency range over which the target pathway is most sensitive to external EMF. Applied signals may thus be configured such that their spectral content closely matches that of the target, using evaluation of the signal to thermal noise ratio to optimize waveform parameters. Using the approach proposed in this study, a pulsed radio frequency (PRF) waveform, currently employed clinically for soft tissue repair, was returned by modulation of burst duration, producing significant bioeffects at substantially reduced signal amplitude. Application is made to Ca2+/Calmodulin-dependent myosin phosphorylation, for which the binding time constants may be estimated from reported kinetics, neurite outgrowth from embryonic chick dorsal root explants and bone repair in a fracture model. The results showed that the retuned signal produced increased phosphorylation rates, neurite outgrowth and biomechanical strength that were indistinguishable from those produced by the clinical signal, but with a tenfold reduction in peak signal amplitude, approximately 800-fold reduction in average amplitude and approximately 10(6)-fold reduction in average power.
An Evaluation of Kinetic Parameters of Cadmium and Copper Biosorption by Immobilized Cells
Directory of Open Access Journals (Sweden)
Nelly Georgieva
2007-10-01
Full Text Available Bioremediation is the use of living organisms to reduce or eliminate environmental hazards resulting from the accumulation of toxic chemicals and other hazardous wastes. This technology is based on the utilization of microorganisms to transform organic and inorganic compounds. The filamentous yeast Trichosporon cutaneum strain R57, immobilized and free cells was cultivated as batch culture on a liquid medium in the presence of various concentrations of cadmium and copper ions. The simultaneous uptake and accumulation of Cd2+ and Cu2+ ions by Tr. cutaneum cells depending on the initial concentration of Cd2+ and Cu2+ in the medium were studied. The potential use of the free and immobilized cells of Trichosporon cutaneum to remove cadmium and copper ions, from aqueous solutions was evaluated. Two important physicochemical aspects for the evaluation of the sorption process as a unit operation are the equilibrium of sorption and the kinetics. The Cd2+ and Cu2+ ions biosorption capacities of all tested adsorbent were presented as a function of the initial concentration of metal ions within the aqueous biosorption medium. The individual, as well as bicomponent sorption kinetics of copper and cadmium ions by immobilised cells of Trichosporon cutaneum R57 is presented. A second order kinetic model obtains kinetic parameters for the copper and cadmium ions.
New method for calculations of nanostructure kinetic stability at high temperature
Fedorov, A. S.; Kuzubov, A. A.; Visotin, M. A.; Tomilin, F. N.
2017-10-01
A new universal method is developed for determination of nanostructure kinetic stability (KS) at high temperatures, when nanostructures can be destroyed by chemical bonds breaking due to atom thermal vibrations. The method is based on calculation of probability for any bond in the structure to stretch more than a limit value Lmax, when the bond breaks. Assuming the number of vibrations is very large and all of them are independent, using the central limit theorem, an expression for the probability of a given bond elongation up to Lmax is derived in order to determine the KS. It is shown that this expression leads to the effective Arrhenius formula, but unlike the standard transition state theory it allows one to find the contributions of different vibrations to a chemical bond cleavage. To determine the KS, only calculation of frequencies and eigenvectors of vibrational modes in the groundstate of the nanostructure is needed, while the transition states need not be found. The suggested method was tested on calculating KS of bonds in some alkanes, octene isomers and narrow graphene nanoribbons of different types and widths at the temperature T=1200 K. The probability of breaking of the C-C bond in the center of these hydrocarbons is found to be significantly higher than at the ends of the molecules. It is also shown that the KS of the octene isomers decreases when the double C˭C bond is moved to the end of the molecule, which agrees well with the experimental data. The KS of the narrowest graphene nanoribbons of different types varies by 1-2 orders of magnitude depending on the width and structure, while all of them are by several orders of magnitude less stable at high temperature than the hydrocarbons and benzene.
Determination of kinetic parameters for 123-I thyroid uptake in healthy Japanese
Kusuhara, Hiroyuki; Maeda, Kazuya
2017-09-01
The purpose of this study was to compare the kinetic parameters for iodide thyroid accumulation in Japanese today with previously reported values. We determined the thyroid uptake of 123-I at 24 hours after the oral administration in healthy male Japanese without any diet restriction. The mean value was 16.1±5.4%, which was similar or rather lower than those previously reported in Japan (1958-1972). Kinetic model analysis was conducted to obtain the clearance for thyroid uptake from the blood circulation. The thyroid uptake clearance of 123-I was 0.540±0.073 ml/min, which was almost similar to those reported previously. There is no obvious difference in the thyroid uptake for 24 hours, and kinetic parameters in healthy Japanese for these 50 years. The fraction of distributed to the thyroid gland is lower than the ICRP reference man, and such difference must be taken into consideration to estimate the radiation exposure upon Fukushima accident in Japan.
Wang, Yuanfeng; Christley, Scott; Mjolsness, Eric; Xie, Xiaohui
2010-07-21
Stochastic effects can be important for the behavior of processes involving small population numbers, so the study of stochastic models has become an important topic in the burgeoning field of computational systems biology. However analysis techniques for stochastic models have tended to lag behind their deterministic cousins due to the heavier computational demands of the statistical approaches for fitting the models to experimental data. There is a continuing need for more effective and efficient algorithms. In this article we focus on the parameter inference problem for stochastic kinetic models of biochemical reactions given discrete time-course observations of either some or all of the molecular species. We propose an algorithm for inference of kinetic rate parameters based upon maximum likelihood using stochastic gradient descent (SGD). We derive a general formula for the gradient of the likelihood function given discrete time-course observations. The formula applies to any explicit functional form of the kinetic rate laws such as mass-action, Michaelis-Menten, etc. Our algorithm estimates the gradient of the likelihood function by reversible jump Markov chain Monte Carlo sampling (RJMCMC), and then gradient descent method is employed to obtain the maximum likelihood estimation of parameter values. Furthermore, we utilize flux balance analysis and show how to automatically construct reversible jump samplers for arbitrary biochemical reaction models. We provide RJMCMC sampling algorithms for both fully observed and partially observed time-course observation data. Our methods are illustrated with two examples: a birth-death model and an auto-regulatory gene network. We find good agreement of the inferred parameters with the actual parameters in both models. The SGD method proposed in the paper presents a general framework of inferring parameters for stochastic kinetic models. The method is computationally efficient and is effective for both partially and fully
Directory of Open Access Journals (Sweden)
Christley Scott
2010-07-01
Full Text Available Abstract Background Stochastic effects can be important for the behavior of processes involving small population numbers, so the study of stochastic models has become an important topic in the burgeoning field of computational systems biology. However analysis techniques for stochastic models have tended to lag behind their deterministic cousins due to the heavier computational demands of the statistical approaches for fitting the models to experimental data. There is a continuing need for more effective and efficient algorithms. In this article we focus on the parameter inference problem for stochastic kinetic models of biochemical reactions given discrete time-course observations of either some or all of the molecular species. Results We propose an algorithm for inference of kinetic rate parameters based upon maximum likelihood using stochastic gradient descent (SGD. We derive a general formula for the gradient of the likelihood function given discrete time-course observations. The formula applies to any explicit functional form of the kinetic rate laws such as mass-action, Michaelis-Menten, etc. Our algorithm estimates the gradient of the likelihood function by reversible jump Markov chain Monte Carlo sampling (RJMCMC, and then gradient descent method is employed to obtain the maximum likelihood estimation of parameter values. Furthermore, we utilize flux balance analysis and show how to automatically construct reversible jump samplers for arbitrary biochemical reaction models. We provide RJMCMC sampling algorithms for both fully observed and partially observed time-course observation data. Our methods are illustrated with two examples: a birth-death model and an auto-regulatory gene network. We find good agreement of the inferred parameters with the actual parameters in both models. Conclusions The SGD method proposed in the paper presents a general framework of inferring parameters for stochastic kinetic models. The method is
The influence of energy migration on luminescence kinetics parameters in upconversion nanoparticles.
Alyatkin, Sergey; Asharchuk, Ilya; Khaydukov, Kirill; Nechaev, Andrey; Lebedev, Oleg; Vainer, Yuri; Semchishen, Vladimir; Khaydukov, Evgeny
2017-01-20
The mechanism of upconversion at the nanoscale is still under discussion. In this paper, we report on the experimental results of anti-Stokes luminescence kinetics in the upconversion nanoparticles of β-NaYF4: 20%Yb3+; 0.6%Tm3+. The parameters of the luminescence kinetics were found to be unambiguously dependent on the number of excitation quanta n, which are necessary for certain transitions between the energy states of thulium ions. The observed correlation has been explained by means of the long-lasting energy migration between the ytterbium ions. The spread in time between the luminescent maxima of the corresponding thulium transitions not only shows the nonlinear character of upconversion, but also reveals the time scale of energy migration as well. From these, we derive that the conventional Förster formalism applied to the estimation of energy transfer efficiency in UCNP-fluorophore pairs can provide misleading results.
The influence of energy migration on luminescence kinetics parameters in upconversion nanoparticles
Alyatkin, Sergey; Asharchuk, Ilya; Khaydukov, Kirill; Nechaev, Andrey; Lebedev, Oleg; Vainer, Yuri; Semchishen, Vladimir; Khaydukov, Evgeny
2017-01-01
The mechanism of upconversion at the nanoscale is still under discussion. In this paper, we report on the experimental results of anti-Stokes luminescence kinetics in the upconversion nanoparticles of β-NaYF4: 20%Yb3+; 0.6%Tm3+. The parameters of the luminescence kinetics were found to be unambiguously dependent on the number of excitation quanta n, which are necessary for certain transitions between the energy states of thulium ions. The observed correlation has been explained by means of the long-lasting energy migration between the ytterbium ions. The spread in time between the luminescent maxima of the corresponding thulium transitions not only shows the nonlinear character of upconversion, but also reveals the time scale of energy migration as well. From these, we derive that the conventional Förster formalism applied to the estimation of energy transfer efficiency in UCNP-fluorophore pairs can provide misleading results.
On the Calculation of Acyl Chain Order Parameters from Lipid Simulations.
Piggot, Thomas J; Allison, Jane R; Sessions, Richard B; Essex, Jonathan W
2017-11-14
For molecular dynamics simulations of biological membrane systems to live up to the potential of providing accurate atomic level detail into membrane properties and functions, it is essential that the force fields used to model such systems are as accurate as possible. One membrane property that is often used to assess force field accuracy is the carbon-hydrogen (or carbon-deuterium) order parameters of the lipid tails, which can be accurately measured using experimental NMR techniques. There are a variety of analysis tools available to calculate these order parameters from simulations and it is essential that these computational tools work correctly to ensure the accurate assessment of the simulation force fields. In this work we compare many of these computational tools for calculating the order parameters of POPC membranes. While tools that work on all-atom systems and tools that work on saturated lipid tails in general work extremely well, we demonstrate that the majority of the tested tools that calculate the order parameters for unsaturated united-atom lipid tails do so incorrectly. We identify tools that do perform accurate calculations and include one such program with this work, enabling rapid and accurate calculation of united-atom lipid order parameters. Furthermore, we discuss cases in which it is nontrivial to appropriately predict the unsaturated carbon order parameters in united-atom systems. Finally, we examine order parameter splitting for carbon 2 in sn-2 lipid chains, demonstrating substantial deviations from experimental values in several all-atom and united-atom lipid force fields.
Energy Technology Data Exchange (ETDEWEB)
Duran, I.; Martinez-Laso, L.
1989-07-01
We present here the methods we used to analyse the characteristic parameters of drift chambers. The algorithms to calculate the electric potential in any point for any drift chamber geometry are presented. We include the description of the programs used to calculate the electric field, the drift paths, the drift velocity and the drift time. The results and the errors are discussed. (Author) 7 refs.
Calculation of the parameter 'deflection' in a new theory of the Earth’s magnetic field
Directory of Open Access Journals (Sweden)
A. de Paor
2002-01-01
Full Text Available In a recent paper on the theory of the Earth's magnetic field and key features of Sunspot activity (de Paor, 2001, a central role in the calculation of secular variations of the geomagnetic field was played by a newly-introduced parameter called the deflection (abbreviated def . In this note, the significance of def is elucidated and the method used to calculate it is explained.
DEFF Research Database (Denmark)
Gaster, M; Schrøder, H D; Handberg, A
2001-01-01
There is no consensus regarding the results from in vivo and in vitro studies on the impact of chronic high insulin and/or high glucose exposure on acute insulin stimulation of glycogen synthase (GS) kinetic parameters in human skeletal muscle. The aim of this study was to evaluate the kinetic pa...
Analysis of JSI TRIGA MARK II reactor physical parameters calculated with TRIPOLI and MCNP.
Henry, R; Tiselj, I; Snoj, L
2015-03-01
New computational model of the JSI TRIGA Mark II research reactor was built for TRIPOLI computer code and compared with existing MCNP code model. The same modelling assumptions were used in order to check the differences of the mathematical models of both Monte Carlo codes. Differences between the TRIPOLI and MCNP predictions of keff were up to 100pcm. Further validation was performed with analyses of the normalized reaction rates and computations of kinetic parameters for various core configurations. Copyright © 2014 Elsevier Ltd. All rights reserved.
Rebutini, Vanessa Z; Pereira, Gleber; Bohrer, Roberta C D; Ugrinowitsch, Carlos; Rodacki, André L F
2016-09-01
Rebutini, VZ, Pereira, G, Bohrer, RCD, Ugrinowitsch, C, and Rodacki, ALF. Plyometric long jump training with progressive loading improves kinetic and kinematic swimming start parameters. J Strength Cond Res 30(9): 2392-2398, 2016-This study was aimed to determine the effects of a plyometric long jump training program on torque around the lower limb joints and kinetic and kinematics parameters during the swimming jump start. Ten swimmers performed 3 identical assessment sessions, measuring hip and knee muscle extensors during maximal voluntary isometric contraction and kinetic and kinematics parameters during the swimming jump start, at 3 instants: INI (2 weeks before the training program, control period), PRE (2 weeks after INI measurements), and POST (24-48 hours after 9 weeks of training). There were no significant changes from INI to PRE measurements. However, the peak torque and rate of torque development increased significantly from PRE to POST measurements for both hip (47 and 108%) and knee (24 and 41%) joints. There were significant improvements to the horizontal force (7%), impulse (9%), and angle of resultant force (19%). In addition, there were significant improvements to the center of mass displacement (5%), horizontal takeoff velocity (16%), horizontal velocity at water entrance (22%), and peak angle velocity for the knee (15%) and hip joints (16%). Therefore, the plyometric long jump training protocol was effective to enhance torque around the lower limb joints and to control the resultant vector direction, to increase the swimming jump start performance. These findings suggest that coaches should use long jump training instead of vertical jump training to improve swimming start performance.
Directory of Open Access Journals (Sweden)
Martin Nikolovski
2014-10-01
Full Text Available Motility patterns of spermatozoa are an indicator of their fertilizing capacity. Reduced glutathione (GSH has been reported to induce positive effects on biological quality of the frozen-thawed spermatozoa. The aim of this study was to investigate the effects of GSH addition to semen extender on the following kinetic parameters: continuous line velocity (VSL, average path velocity (VAP, curvilinear velocity (VCL, amplitude of lateral head displacement (ALH, linearity (LIN, straightness (STR, beat cross frequency (BCF, total motility (tMOT and progressive motility (pMOT, and to appoint them as indicators of its presence. A soybean-based extender was used for dilution of the semen samples, fractioned in two parts, one containing GSH (5 mMol/ml and second without GSH. The ejaculates (n=48 were collected from two rams (January – May, 2013 which were classified in two groups according to the used extender: Group 1 (with GSH, n=24 and Group 2 (without GSH, n=24, and then frozen in liquid nitrogen on -196°C degrees in a programmable freezer. Assessment of the samples has been performed postthawing (30 sec. at 37°C on CASA equipment, acquiring kinetic parameters. Results showed that only VSL and BCF have a statistically significant difference between group1 and group 2 (102.98±15.13 vs. 88.47±20.63, t=2.77, p<0.01 and 32.01±2.68 vs. 89.47±2.92, t=3.13, p<0.01, respectively. The summary of the investigation concludes that none of the kinetic parameters could be appointed as indicators that confer the positive effect of GSH as an additive to soy-bean semen extender.
Abusam, A.A.A.; Keesman, K.J.; Straten, van G.; Spanjers, H.; Meinema, K.
2001-01-01
This paper demonstrates the application of the factorial sensitivity analysis methodology in studying the influence of variations in stoichiometric, kinetic and operating parameters on the performance indices of an oxidation ditch simulation model (benchmark). Factorial sensitivity analysis
Directory of Open Access Journals (Sweden)
Yu.O. Slobodenjuk
2016-07-01
Full Text Available Based on the methods of analysis for calculating the electrical parameters of the mode of the traction power supply systems identified deficiencies related to the readability of the calculation and use of non-sinusoidal currents difficulties in that peculiar modern traction complexes with semiconductor converters. Using the methods of electrical engineering theory developed a model for calculating a continuous instantaneous mode parameters of the traction power supply systems, is different from the calculation methods that have been used previously by the fact that the original data is not averages, and pre-defined instantaneous values of electric current and speed. The model, in contrast to these methods is not large discreteness calculations, which greatly improves the quality of the calculation of the sudden change between the different modes of operation of electric and informative value in the calculation of power quality. The possibility of continuous operation for the entire simulation interval based on the location of the place of electric locomotives that move count distribution of voltage drop, loss of power and non-sinusoidal voltage coefficient for each of the electric contacts in place.
Directory of Open Access Journals (Sweden)
Riionheimo Janne
2003-01-01
Full Text Available We describe a technique for estimating control parameters for a plucked string synthesis model using a genetic algorithm. The model has been intensively used for sound synthesis of various string instruments but the fine tuning of the parameters has been carried out with a semiautomatic method that requires some hand adjustment with human listening. An automated method for extracting the parameters from recorded tones is described in this paper. The calculation of the fitness function utilizes knowledge of the properties of human hearing.
Kinetic parameters and structural variations in Cu-Al-Mn and Cu-Al-Mn-Mg shape memory alloys
Canbay, Canan Aksu
2017-02-01
In this work polycrystalline Cu-Al-Mn and Cu-Al-Mn-Mg SMAs were fabricated by arc melting. The thermal analysis was made to determine the characteristic transformation temperatures of the samples and kinetic parameters. Also the effect of Mg on transformation temperatures and kinetic parameters detected. The structural analysis was made to designate the diffraction planes of martensite phase at room temperature and this was supported by optical measurement observations.
Parameter Identification and On-line Estimation of a Reduced Kinetic Model
Energy Technology Data Exchange (ETDEWEB)
Dellorco, P.C.; Flesner, R.L.; Le, L.A.; Littell, J.D.; Muske, K.R.
1999-02-01
In this work, we present the estimation techniques used to update the model parameters in a reduced kinetic model describing the oxidation-reduction re- actions in a hydrothermal oxidation reactor. The model is used in a nonlinear model-based controller that minimizes the total aqueous nitrogen in the reac- tor effluent. Model reduction is accomplished by com- bining similar reacting compounds into one of four component groups and considering the global reac- tion pathways for each of these groups. The reduced kinetic model developed for thk reaction system pro- vides a means to characterize the complex chemical reaction system without considering each chemicaJ species present and the reaction kinetics of every pos- sible reaction pathway. For the reaction system under study, model reduction is essential in order to reduce the computational requirement so that on-line imple- mentation of the nonlinear model-based controller is possible and also to reduce the amount of a priori information required for the model.
Ariyanto, Eko; Ang, Ha Ming; Sen, Tushar Kanti
2017-09-01
The basic understanding of struvite dissolution chemistry is essential to designers and operators for anticipating struvite problem and remediating existing struvite damage in a wastewater treatment. The dissolution kinetic of struvite seed crystals is very important parameters to determine a solid substance entering in solvent to yield a solution. In this study the dissolution kinetics of struvite crystals (MgNH4PO4·6H2O) in deionized water was investigated in a batch crystallizer. The effects of stirrer speeds, temperature and seed crystals size on the dissolution rate were determined. The results showed that an increase of struvite dissolution rate with increasing stirring speed. Struvite dissolution occurred via a diffusion-controlled mechanism in the range of stirrer speeds 120-400 rpm but became interfacial-reaction-controlling at over 400 rpm. The influence of temperature on dissolution kinetic of struvite crystals was also investigated at stirrer speeds of 200 and 500 rpm. The dissolution rates increased with an increase in the temperature for both stirrer speeds. The change in activation energies at different stirrer speeds confirmed that the change of dissolution mechanism from a diffusion-controlled mechanism at low stirrer speeds to an interfacial-reaction-controlled mechanism at higher stirrer speeds. The dissolution rate of struvite crystals increased with smaller crystal sizes.
Modelling of asteroid formation in planetary vortex and calculation its orbital parameters
Directory of Open Access Journals (Sweden)
L. V. Klychinska
2015-01-01
Full Text Available The theory of planetary vortex as the initial state of creation of the star systems is used to the study of conditions of formation of asteroids and calculation its orbital parameters. In application to Main asteroid belt of the Solar system the kind coincidence of theoretical and experimental data is got.
Sensitivity of NTCP parameter values against a change of dose calculation algorithm
DEFF Research Database (Denmark)
Brink, Carsten; Berg, Martin; Nielsen, Morten
2007-01-01
predicted for a given treatment will in general depend on the algorithm. The purpose of this work is to test whether the optimal NTCP parameter values change significantly when the dose calculation algorithm is changed. The treatment plans for 17 breast cancer patients have retrospectively been recalculated...
Calculation of optimal parameters of an NH3-CO2 lidar
Vasil'ev, BI; Mannoun, OM
The basic parameters (range, signal-to-noise ratio, and sensitivity) of a lidar using NH3 and CO2 lasers are calculated. The principle of lidar operation is based on the differential absorption recording. Absorption spectra of all known Freons are considered in the spectral range 9-13.5 mu m and
Directory of Open Access Journals (Sweden)
Sumanjit
2016-11-01
Full Text Available Adsorption of dye Basic Blue 9 (BB9 was studied using ground nut shells charcoal (GNC, and Eichhornia charcoal (EC as adsorbents. The characterization was done with FTIR spectroscopy, scanning electron microscopy and X-ray diffraction. Batch adsorption studies have been investigated by measuring the effect of pH, adsorbent dose, adsorbate concentration, contact time, temperature, and ionic strength. Adsorption of the dye increased with increase in contact time, temperature, amount of adsorbent and initial concentration. The kinetic experimental data were fitted to pseudo-first order, pseudo-second order, intra-particle diffusion, Elovich model and Bangham’s model and corresponding constants were calculated and discussed. Pseudo-second order kinetics was found to describe the adsorption of dye BB9 on both the adsorbents and rate is mainly controlled by intra particle diffusion. A study of five isotherm models; Langmuir, Freundlich, Temkin, Dubinin and Radushkevich and generalized isotherms have been made and important thermodynamic parameters have been obtained. The adsorption of BB9 onto GNC and EC was spontaneous and endothermic as concluded from thermodynamic assays. Experimental results confirmed that dye BB9 can be successfully removed from the aqueous solutions economically and efficiently.
Crystal Field Parameters and Energy Levels Calculations for Fe3+:ZnGa2O4
Vaida, M.; Brik, M. G.; Avram, N. M.
2010-08-01
In this paper, we present a theoretical study of the energy levels structure for the zinc gallate normal spinel, ZnGa2O4, doped with Fe3+ (3d5 configuration) ions. The calculations have been performed in the framework of the exchange charge model (ECM) of the crystal field. After calculating the CFPs, based on the geometrical structure of the host matrix, the crystal field Hamiltonian was diagonalized in the space spanned by the wave functions of all 16 LS terms of the 3d5 electron configurations. The Racah parameters B, C and G parameter of the exchange charge model have been estimated. The results of the theoretical calculations are in satisfactory agreement with the experimental data.
Energy Technology Data Exchange (ETDEWEB)
Dobos, A. P.
2012-05-01
This paper describes an improved algorithm for calculating the six parameters required by the California Energy Commission (CEC) photovoltaic (PV) Calculator module model. Rebate applications in California require results from the CEC PV model, and thus depend on an up-to-date database of module characteristics. Currently, adding new modules to the database requires calculating operational coefficients using a general purpose equation solver - a cumbersome process for the 300+ modules added on average every month. The combination of empirical regressions and heuristic methods presented herein achieve automated convergence for 99.87% of the 5487 modules in the CEC database and greatly enhance the accuracy and efficiency by which new modules can be characterized and approved for use. The added robustness also permits general purpose use of the CEC/6 parameter module model by modelers and system analysts when standard module specifications are known, even if the module does not exist in a preprocessed database.
Hyperfine electric parameters calculation in Si samples implanted with {sup 57}Mn→{sup 57}Fe
Energy Technology Data Exchange (ETDEWEB)
Abreu, Y., E-mail: yabreu@ceaden.edu.cu [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Calle 30 No. 502 e/5ta y 7ma Ave., 11300 Miramar, Playa, La Habana (Cuba); Cruz, C.M.; Piñera, I.; Leyva, A.; Cabal, A.E. [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Calle 30 No. 502 e/5ta y 7ma Ave., 11300 Miramar, Playa, La Habana (Cuba); Van Espen, P. [Departement Chemie, Universiteit Antwerpen, Middelheimcampus, G.V.130, Groenenborgerlaan 171, 2020 Antwerpen (Belgium); Van Remortel, N. [Departement Fysica, Universiteit Antwerpen, Middelheimcampus, G.U.236, Groenenborgerlaan 171, 2020 Antwerpen (Belgium)
2014-07-15
Nowadays the electronic structure calculations allow the study of complex systems determining the hyperfine parameters measured at a probe atom, including the presence of crystalline defects. The hyperfine electric parameters have been measured by Mössbauer spectroscopy in silicon materials implanted with {sup 57}Mn→{sup 57}Fe ions, observing four main contributions to the spectra. Nevertheless, some ambiguities still remain in the {sup 57}Fe Mössbauer spectra interpretation in this case, regarding the damage configurations and its evolution with annealing. In the present work several implantation environments are evaluated and the {sup 57}Fe hyperfine parameters are calculated. The observed correlation among the studied local environments and the experimental observations is presented, and a tentative microscopic description of the behavior and thermal evolution of the characteristic defects local environments of the probe atoms concerning the location of vacancies and interstitial Si in the neighborhood of {sup 57}Fe ions in substitutional and interstitial sites is proposed.
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Dessy Ariyanti
2013-03-01
Full Text Available Whey is the liquid remaining after milk has been curdled and strained. It is a by-product of the manufacture of cheese or casein and has several commercial uses. In environmental point of view, whey is kind of waste which has high pollution level due to it’s contain high organic compound with BOD and COD value 50 and 80 g/L respectively. On the other side, whey also contain an amount of lactose (4.5%-5%; lactose can be used as carbon source and raw material for producing ethanol via fermentation using yeast strain Kluyveromyces marxianus. The objective of this research is to investigate the ethanol production kinetics from crude whey through fermentation using Kluyveromyces marxianus and to predict the model kinetics parameter. The yeast was able to metabolize most of the lactose within 16 h to give 8.64 g/L ethanol, 4.43 g/L biomass, and remain the 3.122 g/L residual lactose. From the results presented it also can be concluded that common kinetic model for microbial growth, substrate consumption, and product formation is a good alternative to describe an experimental batch fermentation of Kluyveromyces marxianus grown on a medium composed of whey. The model was found to be capable of reflecting all batch culture phases to a certain degree of accuracy, giving the parameter value: μmax, Ks, YX/S, α, β : 0.32, 10.52, 0.095, 1.52, and 0.11 respectively. © 2013 BCREC UNDIP. All rights reserved(Selected Paper from International Conference on Chemical and Material Engineering (ICCME 2012Received: 27th September 2012; Revised: 29th November 2012; Accepted: 7th December 2012[How to Cite: D. Ariyanti, H. Hadiyanto, (2013. Ethanol Production from Whey by Kluyveromyces marxianus in Batch Fermentation System: Kinetics Parameters Estimation. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (3: 179-184. (doi:10.9767/bcrec.7.3.4044.179-184][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.7.3.4044.179-184 ] View in |
Capote, R.; Herman, M.; Obložinský, P.; Young, P. G.; Goriely, S.; Belgya, T.; Ignatyuk, A. V.; Koning, A. J.; Hilaire, S.; Plujko, V. A.; Avrigeanu, M.; Bersillon, O.; Chadwick, M. B.; Fukahori, T.; Ge, Zhigang; Han, Yinlu; Kailas, S.; Kopecky, J.; Maslov, V. M.; Reffo, G.; Sin, M.; Soukhovitskii, E. Sh.; Talou, P.
2009-12-01
We describe the physics and data included in the Reference Input Parameter Library, which is devoted to input parameters needed in calculations of nuclear reactions and nuclear data evaluations. Advanced modelling codes require substantial numerical input, therefore the International Atomic Energy Agency (IAEA) has worked extensively since 1993 on a library of validated nuclear-model input parameters, referred to as the Reference Input Parameter Library (RIPL). A final RIPL coordinated research project (RIPL-3) was brought to a successful conclusion in December 2008, after 15 years of challenging work carried out through three consecutive IAEA projects. The RIPL-3 library was released in January 2009, and is available on the Web through http://www-nds.iaea.org/RIPL-3/. This work and the resulting database are extremely important to theoreticians involved in the development and use of nuclear reaction modelling (ALICE, EMPIRE, GNASH, UNF, TALYS) both for theoretical research and nuclear data evaluations. The numerical data and computer codes included in RIPL-3 are arranged in seven segments: MASSES contains ground-state properties of nuclei for about 9000 nuclei, including three theoretical predictions of masses and the evaluated experimental masses of Audi et al. (2003). DISCRETE LEVELS contains 117 datasets (one for each element) with all known level schemes, electromagnetic and γ-ray decay probabilities available from ENSDF in October 2007. NEUTRON RESONANCES contains average resonance parameters prepared on the basis of the evaluations performed by Ignatyuk and Mughabghab. OPTICAL MODEL contains 495 sets of phenomenological optical model parameters defined in a wide energy range. When there are insufficient experimental data, the evaluator has to resort to either global parameterizations or microscopic approaches. Radial density distributions to be used as input for microscopic calculations are stored in the MASSES segment. LEVEL DENSITIES contains
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Capote, R.; Herman, M.; Capote,R.; Herman,M.; Oblozinsky,P.; Young,P.G.; Goriely,S.; Belgy,T.; Ignatyuk,A.V.; Koning,A.J.; Hilaire,S.; Pljko,V.A.; Avrigeanu,M.; Bersillon,O.; Chadwick,M.B.; Fukahori,T.; Ge, Zhigang; Han,Yinl,; Kailas,S.; Kopecky,J.; Maslov,V.M.; Reffo,G.; Sin,M.; Soukhovitskii,E.Sh.; Talou,P
2009-12-01
We describe the physics and data included in the Reference Input Parameter Library, which is devoted to input parameters needed in calculations of nuclear reactions and nuclear data evaluations. Advanced modelling codes require substantial numerical input, therefore the International Atomic Energy Agency (IAEA) has worked extensively since 1993 on a library of validated nuclear-model input parameters, referred to as the Reference Input Parameter Library (RIPL). A final RIPL coordinated research project (RIPL-3) was brought to a successful conclusion in December 2008, after 15 years of challenging work carried out through three consecutive IAEA projects. The RIPL-3 library was released in January 2009, and is available on the Web through http://www-nds.iaea.org/RIPL-3/. This work and the resulting database are extremely important to theoreticians involved in the development and use of nuclear reaction modelling (ALICE, EMPIRE, GNASH, UNF, TALYS) both for theoretical research and nuclear data evaluations. The numerical data and computer codes included in RIPL-3 are arranged in seven segments: MASSES contains ground-state properties of nuclei for about 9000 nuclei, including three theoretical predictions of masses and the evaluated experimental masses of Audi et al. (2003). DISCRETE LEVELS contains 117 datasets (one for each element) with all known level schemes, electromagnetic and {gamma}-ray decay probabilities available from ENSDF in October 2007. NEUTRON RESONANCES contains average resonance parameters prepared on the basis of the evaluations performed by Ignatyuk and Mughabghab. OPTICAL MODEL contains 495 sets of phenomenological optical model parameters defined in a wide energy range. When there are insufficient experimental data, the evaluator has to resort to either global parameterizations or microscopic approaches. Radial density distributions to be used as input for microscopic calculations are stored in the MASSES segment. LEVEL DENSITIES contains
Electron transport parameters in CO$_2$: scanning drift tube measurements and kinetic computations
Vass, M; Loffhagen, D; Pinhao, N; Donko, Z
2016-01-01
This work presents transport coefficients of electrons (bulk drift velocity, longitudinal diffusion coefficient, and effective ionization frequency) in CO2 measured under time-of-flight conditions over a wide range of the reduced electric field, 15Td <= E/N <= 2660Td in a scanning drift tube apparatus. The data obtained in the experiments are also applied to determine the effective steady-state Townsend ionization coefficient. These parameters are compared to the results of previous experimental studies, as well as to results of various kinetic computations: solutions of the electron Boltzmann equation under different approximations (multiterm and density gradient expansions) and Monte Carlo simulations. The experimental data extend the range of E/N compared with previous measurements and are consistent with most of the transport parameters obtained in these earlier studies. The computational results point out the range of applicability of the respective approaches to determine the different measured tr...
Coxson, P G; Brennan, K M; Huesman, R H; Lim, S; Budinger, T F
1995-02-01
Kinetic analysis of 82Rb dynamic PET data produces quantitative measures which could be used to evaluate ischemic heart disease. These measures have the potential to generate objective comparisons of different patients or the same patient at different times. To achieve this potential, it is essential to determine the variability and reproducibility of the kinetic parameters. A total of 48 82Rb dynamic PET datasets were acquired from two pure bred beagles. Each animal underwent eight 82Rb PET studies with essentially the same protocol for three successive weeks. Data were acquired with the Donner 600-Crystal Positron Tomograph (PET600). In each week, single-slice dynamic 82Rb PET datasets were collected with the animal at rest at three different gantry positions separated by 5 mm. Additional dataset were collected after dipyridamole infusion and after administration of aminophylline to induce a return to rest. A two-compartment kinetic model with correction for myocardial vasculature and spillover from the left ventricular blood pool was used to analyze the dynamic datasets. Model parameters for uptake (k1), washout (k2) and vascular fraction (fv) were estimated in 11-14 myocardial regions of interest (ROIs) using a weighted least-squares criterion. Statistical fluctuation due to the PET acquisition process was minimized by using a relatively high 82Rb dose (about 30 mCi) to take advantage of the high count rate capacity of the PET600. The variation in mean k1, where the mean is taken over the myocardial ROIs was 10%-20% (Dog 1) and 15%-50% (Dog 2) among the rest studies conducted on the same date. Similar variation was evident in comparing studies in the same animal for different weeks. Spatial and temporal variation in estimates of the uptake rate (k1) of 82Rb in the resting myocardium of the anesthetized canine are small in relation to the functional increase in k1 following dipyridamole infusion.
Local field potentials in primate motor cortex encode grasp kinetic parameters.
Milekovic, Tomislav; Truccolo, Wilson; Grün, Sonja; Riehle, Alexa; Brochier, Thomas
2015-07-01
Reach and grasp kinematics are known to be encoded in the spiking activity of neuronal ensembles and in local field potentials (LFPs) recorded from primate motor cortex during movement planning and execution. However, little is known, especially in LFPs, about the encoding of kinetic parameters, such as forces exerted on the object during the same actions. We implanted two monkeys with microelectrode arrays in the motor cortical areas MI and PMd to investigate encoding of grasp-related parameters in motor cortical LFPs during planning and execution of reach-and-grasp movements. We identified three components of the LFP that modulated during grasps corresponding to low (0.3-7Hz), intermediate (~10-~40Hz) and high (~80-250Hz) frequency bands. We show that all three components can be used to classify not only grip types but also object loads during planning and execution of a grasping movement. In addition, we demonstrate that all three components recorded during planning or execution can be used to continuously decode finger pressure forces and hand position related to the grasping movement. Low and high frequency components provide similar classification and decoding accuracies, which were substantially higher than those obtained from the intermediate frequency component. Our results demonstrate that intended reach and grasp kinetic parameters are encoded in multiple LFP bands during both movement planning and execution. These findings also suggest that the LFP is a reliable signal for the control of parameters related to object load and applied pressure forces in brain-machine interfaces. Copyright © 2015 Elsevier Inc. All rights reserved.
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Vazart, Fanny; Latouche, Camille; Skouteris, Dimitrios; Barone, Vincenzo [Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56125 Pisa (Italy); Balucani, Nadia [Dipartimento di Chimica, Biologia e Biotecnologie, Universitá degli Studi di Perugia, Via Elce di Sotto 8, I-06123 Perugia (Italy)
2015-09-10
New insights into the formation of interstellar cyanomethanimine, a species of great relevance in prebiotic chemistry, are provided by electronic structure and kinetic calculations for the reaction CN + CH{sub 2} = NH. This reaction is a facile formation route of Z,E-C-cyanomethanimine, even under the extreme conditions of density and temperature typical of cold interstellar clouds. E-C-cyanomethanimine has been recently identified in Sgr B2(N) in the Green Bank Telescope (GBT) PRIMOS survey by P. Zaleski et al. and no efficient formation routes have been envisaged so far. The rate coefficient expression for the reaction channel leading to the observed isomer E-C-cyanomethanimine is 3.15 × 10-10 × (T/300){sup 0.152} × e{sup (−0.0948/T)}. According to the present study, the more stable Z-C-cyanomethanimine isomer is formed with a slightly larger yield (4.59 × 10{sup −10} × (T/300){sup 0.153} × e{sup (−0.0871/T)}. As the detection of E-isomer is favored due to its larger dipole moment, the missing detection of the Z-isomer can be due to the sensitivity limit of the GBT PRIMOS survey and the detection of the Z-isomer should be attempted with more sensitive instrumentation. The CN + CH{sub 2} = NH reaction can also play a role in the chemistry of the upper atmosphere of Titan where the cyanomethanimine products can contribute to the buildup of the observed nitrogen-rich organic aerosols that cover the moon.
Effect of Drop Foot on Spatiotemporal, Kinematic, and Kinetic Parameters during Gait
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Ida Wiszomirska
2017-01-01
Full Text Available Background. The complexity of the structure and function of a living body can be affected by disorders and can cause various dysfunctions. Objective. The aim of this study was to determine compensatory mechanisms in subjects with drop foot during gait. Methods. The study evaluated 10 subjects with drop foot (DF whose results were compared to a group of 10 healthy controls (C. Spatiotemporal, kinematic, and kinetic parameters during the gait cycle were collected using Vicon system synchronized with Kistler platforms. Results. Spatiotemporal, kinematic, and kinetic parameters were significantly different between the analysed groups. In the DF group, the subjects walked almost 47% slower and performed 60% less steps per minute compared to the C group. The main problem in the DF group was insufficient ankle dorsiflexion in the 0–10% of the gait cycle. Mean values in the groups during the first 10% of the gait cycle were as follows: DF (−10.42 ± 5.7° and C (−2.37 ± 1.47°, which affected the substantial differences in the values of muscle torque: DF (0.2 ± 0.1 Nm/kg and C (−0.26 ± 0.06 Nm/kg. Conclusions. Comparative analysis for joint angles and torques demonstrated that the mechanism of compensation is the most noticeable in the knee joint and less in the hip joint.
Xie, Dongming; Liu, Dehua; Zhu, Haoli; Zhang, Jianan
2002-05-01
To optimize the fed-batch processes of glycerol fermentation in different reactor states, typical bioreactors including 500-mL shaking flask, 600-mL and 15-L airlift loop reactor, and 5-L stirred vessel were investigated. It was found that by reestimating the values of only two variable kinetic parameters associated with physical transport phenomena in a reactor, the macrokinetic model of glycerol fermentation proposed in previous work could describe well the batch processes in different reactor states. This variable kinetic parameter (VKP) approach was further applied to model-based optimization of discrete-pulse feed (DPF) strategies of both glucose and corn steep slurry for glycerol fed-batch fermentation. The experimental results showed that, compared with the feed strategies determined just by limited experimental optimization in previous work, the DPF strategies with VKPs adjusted could improve glycerol productivity at least by 27% in the scale-down and scale-up reactor states. The approach proposed appeared promising for further modeling and optimization of glycerol fermentation or the similar bioprocesses in larger scales.
Soluble fractions and kinetics parameters of nitrate and ammonium uptake in sunflower (“Neon” Hybrid
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Luiziene Soares Alves
Full Text Available ABSTRACT Sunflower plants are source of oilseeds with great importance for agroenergy. Nitrogen deficiency is considered one of the factors limiting growth and yield. The objective of this study was to assess the nitrogen uptake (high and low supply of nitrate and ammonium and to determine the uptake kinetics parameters (Km and Vmax of these ions in sunflower plants (Neon hybrid. The experiment was carried out in a growth chamber using a hydroponic system. The following treatments were applied: 0.2 and 2.0 mmol L-1 of N-NO3- and N-NH4+. The two kinetics parameters (Km and Vmax involved in the uptake of nitrate and ammonium were determined, as well as the soluble fractions (N-NO3-, N-NH4+, amino-N and sugars and total N, in different plant tissues. The plants grown with ammonium showed higher Vmax than those cultivated with nitrate. High ammonium rates caused reduction of root volume and the plants supplied with 2.0 mmol L-1 of N-NO3- produced more biomass from the roots and aerial part. The highest concentrations of NNO3- were found in the petioles. Analyzed together, the data suggest a greater potential for use of nitric-N as a nitrogen source for fertilization in the cultivation of sunflower.
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V. V. Ivashechkin
2014-01-01
Full Text Available The purpose of this work is the study of decolmatation rate of granular layer of gravel pack of well during creating inside of it flushing of reagent with given hydrodynamic parameters and determination the duration of treatment. This article deals with radical movement of chemical solutions by injection of it outside of gravel pack of filter when the flow directs to borehole axis under conditions of quasi-steady-state mode of filtration for equal yield of input and output reagent from borehole.Colmataged layer of gravel pack is schematized in the form of porous ring cylinder with outside radius which is equal to radius of line of gravel pack and the height which is equal to the length of filter made in formation drilling and inside radius which is equal to radius of filter. Initial saturation of subsoil with colmatant is given. It was accepted that reagent with given rate flows through outside surface of ring cylinder equal along all height. Near-filtering zone is given uniform and movement is quasi-steady-state.Equations’ system is composed including: joint equation of movement and mass conservation and generalized equation of kinetics, which describes kinetics of colmatant dissolution in the regime of out-pipe watering of ring gravel pack of well taking into account the change of structure of porous medium. The analytic solution of equations’ system was obtained, which allow to calculate salt content in reagent during the leaching process and to determine the specific volume of deposits in the point of gravel pack at any moment of time in the process of regent injection. The analytic dependence was obtained for calculation of duration of complete regeneration of soil grains’ layer of outer contour of gravel packing. For calculation of duration of full regeneration of the whole thickness of packing it is suggested to divide the regeneration period into a series of stages of salt transferring from subsoil. Duration of one stage is equal
Integration based profile likelihood calculation for PDE constrained parameter estimation problems
Boiger, R.; Hasenauer, J.; Hroß, S.; Kaltenbacher, B.
2016-12-01
Partial differential equation (PDE) models are widely used in engineering and natural sciences to describe spatio-temporal processes. The parameters of the considered processes are often unknown and have to be estimated from experimental data. Due to partial observations and measurement noise, these parameter estimates are subject to uncertainty. This uncertainty can be assessed using profile likelihoods, a reliable but computationally intensive approach. In this paper, we present the integration based approach for the profile likelihood calculation developed by (Chen and Jennrich 2002 J. Comput. Graph. Stat. 11 714-32) and adapt it to inverse problems with PDE constraints. While existing methods for profile likelihood calculation in parameter estimation problems with PDE constraints rely on repeated optimization, the proposed approach exploits a dynamical system evolving along the likelihood profile. We derive the dynamical system for the unreduced estimation problem, prove convergence and study the properties of the integration based approach for the PDE case. To evaluate the proposed method, we compare it with state-of-the-art algorithms for a simple reaction-diffusion model for a cellular patterning process. We observe a good accuracy of the method as well as a significant speed up as compared to established methods. Integration based profile calculation facilitates rigorous uncertainty analysis for computationally demanding parameter estimation problems with PDE constraints.
Huang, Lihan
2015-02-16
The objective of this research was to develop a new one-step methodology that uses a dynamic approach to directly construct a tertiary model for prediction of the growth of Clostridium perfringens in cooked beef. This methodology was based on simultaneous numerical analysis and optimization of both primary and secondary models using multiple dynamic growth curves obtained under different conditions. Once the models were constructed, the bootstrap method was used to calculate the 95% confidence intervals of kinetic parameters, and a Monte Carlo simulation method was developed to validate the models using the growth curves not previously used in model development. The results showed that the kinetic parameters obtained from this study accurately matched the common characteristics of C. perfringens, with the optimum temperature being 45.3°C. The results also showed that the predicted growth curves matched accurately with experimental observations used in validation. The mean of residuals of the predictions is -0.02logCFU/g, with a standard deviation of only 0.23logCFU/g. For relative growths 0.4logCFU/g, while only 1.5% are >0.8logCFU/g. In addition, the dynamic model also accurately predicted four isothermal growth curves arbitrarily chosen from the literature. Finally, the Monte Carlo simulation was used to provide the probability of >1 and 2logCFU/g relative growths at the end of cooling. The results of this study will provide a new and accurate tool to the food industry and regulatory agencies to assess the safety of cooked beef in the event of cooling deviation. Published by Elsevier B.V.
De Luis, R; Pérez, M D; Sánchez, L; Lavilla, M; Calvo, M
2008-08-01
The effect of heat treatment on the denaturation of Cry1A(b) protein expressed in transgenic maize was studied over a temperature range of 69 to 77 degrees C. Denaturation of Cry1A(b) protein was measured by the loss of reactivity with its specific antibodies using a sandwich ELISA. The process of denaturation was studied by analyzing the values of inmunoreactive protein after each heat treatment by kinetic analysis. Denaturation of Cry1A(b) protein was best described assuming a reaction order of 1.5. D-values calculated were 4338, 2350, 1272, 734, and 601 s at 69, 71, 73, 75, and 77 degrees C, respectively. Z-value was estimated to be 9.0 degrees C and the activation energy value was 266.15 kJ/mol. Thermodynamic parameters for the process of denaturation of Cry1A(b) protein were also calculated. The high values of the enthalpy of activation and the positive values of the entropy of activation obtained for Cry1A(b) protein are typical of a reaction in which the denaturation of the protein is the rate-determining process that predominates over an aggregation process during heating.
Calculating Gamma Camera Uniformity Parameters: Beyond the Vendor-specific Protocol.
Pandey, Anil Kumar; Sharma, Param Dev; Kumar, Jay Prakash; Saroha, Kartik; Patel, Chetan; Bal, Chandra Sekhar; Kumar, Rakesh
2017-01-01
The aim of this study was to develop and verify a personal computer-based software tool for calculating uniformity indices of gamma camera. The program was developed in MATLAB R2013b under Microsoft Windows operating system. Noise-less digital phantoms with known uniformity parameters were used to verify the accuracy of the program. Two hundred and forty-four Co-57 flood source images were acquired on Symbia T6 and Discovery nuclear medicine/computed tomography 670. The uniformity indices of these images were determined with their respective vendor's software and also by the tool developed. Bland-Altman plots were used for measuring the agreements between the developed program and the vendor's program for the calculation of uniformity indices. The tool for calculating uniformity indices was found to be accurate. Uniformity indices measured with the tool revealed a very good correlation with vendor's software based on Bland-Altman analysis, as almost all measurements were within the ±2 standard deviation range. The software tool for calculation of uniformity indices is accurate, and the uniformity indices calculated by it are in agreement with uniformity indices calculated by the vendor's software.
Parameter-free effective field theory calculation for the solar proton-fusion and hep processes
Energy Technology Data Exchange (ETDEWEB)
T.S. Park; L.E. Marcucci; R. Schiavilla; M. Viviani; A. Kievsky; S. Rosati; K. Kubodera; D.P. Min; M. Rho
2002-08-01
Spurred by the recent complete determination of the weak currents in two-nucleon systems up to {Omicron}(Q{sup 3}) in heavy-baryon chiral perturbation theory, we carry out a parameter-free calculation of the threshold S-factors for the solar pp (proton-fusion) and hep processes in an effective field theory that combines the merits of the standard nuclear physics method and systematic chiral expansion. The power of the EFT adopted here is that one can correlate in a unified formalism the weak-current matrix elements of two-, three- and four-nucleon systems. Using the tritium {beta}-decay rate as an input to fix the only unknown parameter in the theory, we can evaluate the threshold S factors with drastically improved precision; the results are S{sub pp}(0) = 3.94 x (1 {+-} 0.004) x 10{sup -25} MeV-b and S{sub hep}(0) = (8.6 {+-} 1.3) x 10{sup -20} keV-b. The dependence of the calculated S-factors on the momentum cutoff parameter {Lambda} has been examined for a physically reasonable range of {Lambda}. This dependence is found to be extremely small for the pp process, and to be within acceptable levels for the hep process, substantiating the consistency of our calculational scheme.
Kobayashi, Ryo; Otomo, Shinya; Shiba, Yusuke; Ebinuma, Keiichi; Sudoh, Toshiaki
2016-01-01
According to a recent study and meta-analysis, trough levels of >10 μg/mL teicoplanin (TEIC) may be acceptable for the treatment of uncomplicated infection, but no method of TEIC personalized medicine has been established. Vancomycin (VCM) and TEIC are glycopeptide antibiotic agents effective against methicillin-resistance Staphyloccocus aureus. This study aimed to establish TEIC personalized medicine at a steady state calculated by VCM pharmacokinetic parameters. Bayesian forecasting and population mean methods were employed to estimate individual total VCM clearance (CL) using existing population pharmacokinetics (PPK) parameter, and the differences between the CL calculated by these two methods were defined as ΔCL. Serum drug concentration data for patients treated with TEIC were collected at a steady state concentration (>96 h post infusion). There was a significant relationship between the prediction error of TEIC trough level and ΔCL. The relation between ΔCL and TEIC trough concentration at steady state was used to develop the following equation to determine the maintenance dose: TEIC (μg/mL)=1.1119X-6.124ΔCL+3.9164 (X is defined as TEIC trough concentration calculated from the PPK parameter). The results of this study indicated that it is possible to improve the prediction error of TEIC trough concentration at a steady state for patients who have received VCM therapy.
Directory of Open Access Journals (Sweden)
Aline B. Denis
2016-01-01
Full Text Available This study aimed to analyze the kinetic parameters of two monomers using attenuated total reflectance Fourier transform infrared (ATR-FTIR: 2,2-bis-[4-(2-hydroxy-3-methacryloxypropyl-1-oxy-phenyl] propane (Bis-GMA and triethylene glycol dimethacrylate (TEGDMA. The following were calculated to evaluate the kinetic parameters: maximum conversion rate (Rpmax, time at the maximum polymerization rate (tmax, conversion at Rpmax, and total conversion recorded at the maximum conversion point after 300 s. Camphorquinone (CQ and phenyl propanedione (PPD were used in this study as photoinitiators, whereas N,N-dimethyl-p-toluidine (DMPT amine was used as a coinitiator. LED apparatus and halogen lamp were used in turn to evaluate the effect that light source had on the monomer kinetics. The mass concentration ratio for the three resin preparations was 0.7 : 0.3 for Bis-GMA and TEGDMA: R1 (CQ + DMPT, R2 (PPD + DMPT, and R3 (PPD + CQ + DMPT. The PPD association with the CQ photoinitiator altered the polymerization kinetics compared to a resin containing only the CQ photoinitiator. The light sources exhibited no significant differences for tmax of R1 and R3. Resins containing only the PPD initiator exhibited a higher tmax than those containing only CQ. However, the Rpmax decreased for resins containing the PPD photoinitiator.
One-Dimensional Modeling of an Entrained Coal Gasification Process Using Kinetic Parameters
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Moonkyeong Hwang
2016-02-01
Full Text Available A one-dimensional reactor model was developed to simulate the performance of an entrained flow gasifier under various operating conditions. The model combined the plug flow reactor (PFR model with the well-stirred reactor (WSR model. Reaction kinetics was considered together with gas diffusion for the solid-phase reactions in the PFR model, while equilibrium was considered for the gas-phase reactions in the WSR model. The differential and algebraic equations of mass balance and energy balance were solved by a robust ODE solver, i.e., an semi-implicit Runge–Kutta method, and by a nonlinear algebraic solver, respectively. The computed gasifier performance was validated against experimental data from the literature. The difference in product gas concentration from the equilibrium model, and the underlying mechanisms were discussed further. The optimal condition was found after parameter studies were made for various operating conditions.
Calculation and Identification of the Aerodynamic Parameters for Small-Scaled Fixed-Wing UAVs.
Shen, Jieliang; Su, Yan; Liang, Qing; Zhu, Xinhua
2018-01-13
The establishment of the Aircraft Dynamic Model(ADM) constitutes the prerequisite for the design of the navigation and control system, but the aerodynamic parameters in the model could not be readily obtained especially for small-scaled fixed-wing UAVs. In this paper, the procedure of computing the aerodynamic parameters is developed. All the longitudinal and lateral aerodynamic derivatives are firstly calculated through semi-empirical method based on the aerodynamics, rather than the wind tunnel tests or fluid dynamics software analysis. Secondly, the residuals of each derivative are proposed to be identified or estimated further via Extended Kalman Filter(EKF), with the observations of the attitude and velocity from the airborne integrated navigation system. Meanwhile, the observability of the targeted parameters is analyzed and strengthened through multiple maneuvers. Based on a small-scaled fixed-wing aircraft driven by propeller, the airborne sensors are chosen and the model of the actuators are constructed. Then, real flight tests are implemented to verify the calculation and identification process. Test results tell the rationality of the semi-empirical method and show the improvement of accuracy of ADM after the compensation of the parameters.
Calculation and Identification of the Aerodynamic Parameters for Small-Scaled Fixed-Wing UAVs
Shen, Jieliang; Su, Yan; Liang, Qing; Zhu, Xinhua
2018-01-01
The establishment of the Aircraft Dynamic Model (ADM) constitutes the prerequisite for the design of the navigation and control system, but the aerodynamic parameters in the model could not be readily obtained especially for small-scaled fixed-wing UAVs. In this paper, the procedure of computing the aerodynamic parameters is developed. All the longitudinal and lateral aerodynamic derivatives are firstly calculated through semi-empirical method based on the aerodynamics, rather than the wind tunnel tests or fluid dynamics software analysis. Secondly, the residuals of each derivative are proposed to be identified or estimated further via Extended Kalman Filter (EKF), with the observations of the attitude and velocity from the airborne integrated navigation system. Meanwhile, the observability of the targeted parameters is analyzed and strengthened through multiple maneuvers. Based on a small-scaled fixed-wing aircraft driven by propeller, the airborne sensors are chosen and the model of the actuators are constructed. Then, real flight tests are implemented to verify the calculation and identification process. Test results tell the rationality of the semi-empirical method and show the improvement of accuracy of ADM after the compensation of the parameters. PMID:29342856
Bubbico, Roberto; Mazzarotta, Barbara
2008-03-01
In the present paper the accidental release of toxic chemicals has been taken into consideration, and a sensitivity analysis study of the corresponding consequences calculation has been carried out. Four different toxic chemicals have been chosen for the simulations, and the effect of the variability of the main input parameters on the extension of the impact areas has been assessed. The results show that the influence of these parameters depends on the physical properties of the released substance and that not always the widely known rules of thumb, such as the positive influence of the wind velocity on gas dispersion, apply. In particular, the boiling temperature of the chemical has revealed to be the main parameter affecting the type of dependence of the impact distances on the input variables.
Agostinho, F S; Rahal, S C; Geraldo, B; Justolin, P L T; Teixeira, C R; Lins, F L M L; Monteiro, F O B
2015-01-01
To evaluate the influence on the kinetic and temporospatial parameters of calibration protocols with point and step techniques for a pressure-sensing walkway. Nine Labrador dogs were used. Two protocols of point calibration technique (C1 and C2) and eight protocols of step calibration technique (C3 to C10) were performed. In C1, weight was added to a stool to match the body mass of each dog. In C2, weight was added to the stool to match a 46.1 kg person. The other eight calibration protocols represented combinations of the following factors: 46.1 kg and 96.1 kg persons, barefoot or wearing sneakers, and stepping onto the platform with one or two feet. The calibration protocols did not affect the temporospatial variables or percentages of body weight (%BW) distribution. Significant differences were found in both PVI (peak vertical force) and VI (vertical impulse) between barefoot versus wearing sneakers, 46.1 kg versus 96.1 kg person, and stepping onto the platform with one foot versus two feet. When comparing C1 with other protocols, significant differences were observed in PVF and VI for both forelimbs and hindlimbs. When comparing C2 with other protocols, significant differences were observed in PVF and VI for both forelimbs and hindlimbs in all protocols. The PVF and VI were influenced by the calibration protocol used, but the %BW distribution and temporospatial parameters were not. Using the same calibration protocol for all dogs within the same group eliminated the variability of the kinetic data caused by the calibration.
Tosun, Ismail
2012-03-01
The adsorption isotherm, the adsorption kinetics, and the thermodynamic parameters of ammonium removal from aqueous solution by using clinoptilolite in aqueous solution was investigated in this study. Experimental data obtained from batch equilibrium tests have been analyzed by four two-parameter (Freundlich, Langmuir, Tempkin and Dubinin-Radushkevich (D-R)) and four three-parameter (Redlich-Peterson (R-P), Sips, Toth and Khan) isotherm models. D-R and R-P isotherms were the models that best fitted to experimental data over the other two- and three-parameter models applied. The adsorption energy (E) from the D-R isotherm was found to be approximately 7 kJ/mol for the ammonium-clinoptilolite system, thereby indicating that ammonium is adsorbed on clinoptilolite by physisorption. Kinetic parameters were determined by analyzing the nth-order kinetic model, the modified second-order model and the double exponential model, and each model resulted in a coefficient of determination (R(2)) of above 0.989 with an average relative error lower than 5%. A Double Exponential Model (DEM) showed that the adsorption process develops in two stages as rapid and slow phase. Changes in standard free energy (∆G°), enthalpy (∆H°) and entropy (∆S°) of ammonium-clinoptilolite system were estimated by using the thermodynamic equilibrium coefficients.
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İsmail Tosun
2012-03-01
Full Text Available The adsorption isotherm, the adsorption kinetics, and the thermodynamic parameters of ammonium removal from aqueous solution by using clinoptilolite in aqueous solution was investigated in this study. Experimental data obtained from batch equilibrium tests have been analyzed by four two-parameter (Freundlich, Langmuir, Tempkin and Dubinin-Radushkevich (D-R and four three-parameter (Redlich-Peterson (R-P, Sips, Toth and Khan isotherm models. D-R and R-P isotherms were the models that best fitted to experimental data over the other two- and three-parameter models applied. The adsorption energy (E from the D-R isotherm was found to be approximately 7 kJ/mol for the ammonium-clinoptilolite system, thereby indicating that ammonium is adsorbed on clinoptilolite by physisorption. Kinetic parameters were determined by analyzing the nth-order kinetic model, the modified second-order model and the double exponential model, and each model resulted in a coefficient of determination (R2 of above 0.989 with an average relative error lower than 5%. A Double Exponential Model (DEM showed that the adsorption process develops in two stages as rapid and slow phase. Changes in standard free energy (∆G°, enthalpy (∆H° and entropy (∆S° of ammonium-clinoptilolite system were estimated by using the thermodynamic equilibrium coefficients.
Yazici, A N
2003-01-01
In this paper, the thermal bleaching curves (TBCs) of specific optical absorption bands of LiF : Mg,Ti were measured as a function of temperature. The TBCs obtained were analysed to extract the kinetic parameters (the thermal activation energy (E) and the frequency factor (s)) of some TL glow peaks of LiF : Mg,Ti on the basis of the developed first-order kinetic model over a specified temperature region.
Energy Technology Data Exchange (ETDEWEB)
Pereira, A.; Broed, R. [AlbaNova Univ. Center, Stockholm (Sweden). Stockholm Center for Physics Astronomy and Biotechnology
2002-03-01
In this report, several issues related to the probabilistic methodology for performance assessments of repositories for high-level nuclear waste and spent fuel are addressed. Random Monte Carlo sampling is used to make uncertainty analyses for the migration of four nuclides and a decay chain in the geosphere. The nuclides studied are cesium, chlorine, iodine and carbon, and radium from a decay chain. A procedure is developed to take advantage of the information contained in the hydrogeological data obtained from a three-dimensional discrete fracture model as the input data for one-dimensional transport models for use in Monte Carlo calculations. This procedure retains the original correlations between parameters representing different physical entities, namely, between the groundwater flow rate and the hydrodynamic dispersion in fractured rock, in contrast with the approach commonly used that assumes that all parameters supplied for the Monte Carlo calculations are independent of each other. A small program is developed to allow the above-mentioned procedure to be used if the available three-dimensional data are scarce for Monte Carlo calculations. The program allows random sampling of data from the 3-D data distribution in the hydrogeological calculations. The impact of correlations between the groundwater flow and the hydrodynamic dispersion on the uncertainty associated with the output distribution of the radionuclides' peak releases is studied. It is shown that for the SITE-94 data, this impact can be disregarded. A global sensitivity analysis is also performed on the peak releases of the radionuclides studied. The results of these sensitivity analyses, using several known statistical methods, show discrepancies that are attributed to the limitations of these methods. The reason for the difficulties is to be found in the complexity of the models needed for the predictions of radionuclide migration, models that deliver results covering variation of several
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S. Kremser
2011-06-01
Full Text Available Key kinetic parameters governing the partitioning of chlorine species in the Antarctic polar stratosphere were retrieved from 28 days of chlorine monoxide (ClO microwave radiometer measurements made during the late winter/early spring of 2005 at Scott Base (77.85° S, 166.75° E. During day-time the loss of the ClO dimer chlorine peroxide (ClOOCl occurs mainly by photolysis. Some time after sunrise, a photochemical equilibrium is established and the ClO/ClOOCl partitioning is determined by the ratio of the photolysis frequency, J, and the dimer formation rate, k_{f}. The values of J and k_{f} from laboratory studies remain uncertain to a considerable extent, and as a complement to these ongoing studies, the goal of this work is to provide a constraint on that uncertainty based on observations of ClO profiles in the Antarctic. First an optimal estimation technique was used to derive J/k_{f} ratios for a range of K_{eq} values. The optimal estimation forward model was a photochemical box model that takes J, k_{f}, and K_{eq} as inputs, together with a priori profiles of activated chlorine (ClO_{x} = ClO+2×ClOOCl, profiles of ozone, temperature, and pressure. JPL06 kinetics are used as a priori in the optimal estimation and for all other chemistry in the forward model. Using the more recent JPL09 kinetics results in insignificant differences in the retrieved value of J/k_{f}. A complementary approach was used to derive the optimal kinetic parameters; the full parameter space of J, k_{f}, K_{eq} and ClO_{x} was sampled to find the minimum in differences between measured and modelled ClO profiles. Furthermore, values of K_{eq} up to 2.0 times larger than recommended by JPL06 were explored to test the sensitivity of the
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Lopes Antonio
2009-01-01
Full Text Available Background : In patients with congenital heart disease undergoing cardiac catheterization for hemodynamic purposes, parameter estimation by the indirect Fick method using a single predicted value of oxygen consumption has been a matter of criticism. Objective : We developed a computer-based routine for rapid estimation of replicate hemodynamic parameters using multiple predicted values of oxygen consumption. Materials and Methods : Using Microsoft ® Excel facilities, we constructed a matrix containing 5 models (equations for prediction of oxygen consumption, and all additional formulas needed to obtain replicate estimates of hemodynamic parameters. Results : By entering data from 65 patients with ventricular septal defects, aged 1 month to 8 years, it was possible to obtain multiple predictions for oxygen consumption, with clear between-age groups ( P < .001 and between-methods ( P < .001 differences. Using these predictions in the individual patient, it was possible to obtain the upper and lower limits of a likely range for any given parameter, which made estimation more realistic. Conclusion : The organized matrix allows for rapid obtainment of replicate parameter estimates, without error due to exhaustive calculations.
Lopes, Antonio Augusto; Dos Anjos Miranda, Rogério; Gonçalves, Rilvani Cavalcante; Thomaz, Ana Maria
2009-07-01
In patients with congenital heart disease undergoing cardiac catheterization for hemodynamic purposes, parameter estimation by the indirect Fick method using a single predicted value of oxygen consumption has been a matter of criticism. We developed a computer-based routine for rapid estimation of replicate hemodynamic parameters using multiple predicted values of oxygen consumption. Using Microsoft® Excel facilities, we constructed a matrix containing 5 models (equations) for prediction of oxygen consumption, and all additional formulas needed to obtain replicate estimates of hemodynamic parameters. By entering data from 65 patients with ventricular septal defects, aged 1 month to 8 years, it was possible to obtain multiple predictions for oxygen consumption, with clear between-age groups (P <.001) and between-methods (P <.001) differences. Using these predictions in the individual patient, it was possible to obtain the upper and lower limits of a likely range for any given parameter, which made estimation more realistic. The organized matrix allows for rapid obtainment of replicate parameter estimates, without error due to exhaustive calculations.
National Research Council Canada - National Science Library
V. T. Erofeenko
2015-01-01
.... Under the calculations of parameters, taking into account a multiple scattering of the field between particles, a new type of addition theorems, connecting basic spherical electromagnetic fields...
MODELING AND CALCULATION OF FLOW AMPLIFIER PARAMETERS IN STEERING OF HEAVY TRUCKS
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V. P. Avtushko
2008-01-01
Full Text Available The paper analyzes prospects pertaining to development of methods for dynamic calculation of monitoring hydraulic units with various types of relations. Calculated diagram of steering hydraulic drive with flow amplifier and turning cylinder has been given in the paper and its dynamic model has been developed. A hydraulic drive is considered as a system with lumped parameters. It is supposed that properties of working fluid are unchangeable during transient process; leakages and cavitations do not occur; fluid can be pressed; resistance of service drain line is taken into account. Model has been developed with due account of resistance of manifolds and internal channels of flow amplifier, hydrodynamic forces, that influence on amplifier control valves, and friction forces of movable elements. Multi-variant dynamic calculation has been done and some results of the investigations are presented in the paper. The paper also contains analysis that shows influence of various design and component parameters of flow amplifier on the drive dynamics.
Influential parameters for designing and power consumption calculating of cumin mower
Energy Technology Data Exchange (ETDEWEB)
Mahmoodi, E.; Jafari, A. [Tehran Univ., Karaj (Iran, Islamic Republic of). Dept. of Agricultural Machinery Engineering
2010-07-01
This paper reported on a study in which the consuming power and design of cumin mowers was calculated. The parameters required for calculating power consumption and designing of cumin mowers were measured along with some engineering properties of cumin stems. These included shearing and bending tests on cumin stem and specifying the coefficient of friction between mower knives and cumin stem. The relationships between static and dynamic friction forces being exerted on mower runners by soil with normal load were determined along with the factor affecting soil moisture. Some of the other parameters that are important for calculating the power consumption and design of an optimized mower include harvest moisture content; maximum and average of cumin stem diameter; maximum bio-yield point of force and maximum ultimate point of force in the cutting; average energy required to cut a stem; maximum elasticity module; maximum bending rupture force; average energy required for bending a stem; friction coefficient between the stem and knife edge; relation between bio-yield force, failure force, elasticity and diameter in the cutting; relation between rupture forces and diameter in the bending; and mower weight.
Energy Technology Data Exchange (ETDEWEB)
Sepulveda M, F. [ESFM-IPN, 07738 Mexico D.F. (Mexico); Azorin N, J.; Rivera M, T. [UAM-I, 09340 Mexico D.F. (Mexico); Furetta, C.; Sanipoli, C. [Physics Department, Universita di Roma ' ' La Sapienza' ' , Piazzale A. Moro 2, 00185 Roma (Italy)
2004-07-01
The thermoluminescent curves induced by the beta radiation in the perovskite KMgF{sub 3} were investigated activated with lanthanum. The classic methods were used to determine the kinetic parameters (the kinetic order b, the activation energy E and the frequency of escape intent s) associated with the peaks of the thermoluminescent curve (Tl) in the KMgF{sub 3} activated with lanthanum after the irradiation with beta rays. The method is based on the position of the thermoluminescent peaks, obtained of the temperature change of the peak in the maximum emission caused by the change in the heating rapidity to which the samples were measured. In this work, the samples in form of pellets were re cooked previously at 400 C during one hour before irradiating them with beta particles. The Tl measures were made with a Tl reader system using three different heating rapidities and storing the glow curves. To calculate the depth of the E traps and the frequency factor s, the parameters of the glow curve were determined experimentally of the shame of the glow curve by means of the mensuration of the shame of the maximum temperature of the peak, T{sub M} like a function of the heating rapidity. The results indicate that the values of the kinetic parameters are very near among if when they are obtained indistinctly of anyone of the different methods. (Author)
Updated parameters for HL-LHC aperture calculations for proton beams
Bruce, Roderik; De Maria, Riccardo; Giovannozzi, Massimo; Redaelli, Stefano; Tomas Garcia, Rogelio; Velotti, Francesco Maria; Wenninger, Jorg
2017-01-01
During the accelerator design, it is important to have a reliable way of estimating the available aperture, in order to ensure a sufficient beam clearing and avoid potentially limiting beam losses on the aperture. Such calculations can be performed using MAD-X, taking as input the beam parameters and the tolerances of, e.g., orbit and optics. Realistic tolerances and an accurate criterion for qualifying the aperture are crucial during the design stage, in order to ensure that all machine apertures are sufficiently protected from harmful beam losses. Previous studies have provided such parameter sets for aperture calculations for both LHC and HL-LHC. This report provides an update to the previous HL-LHC parameters at top energy. First we study the protected aperture that can be tolerated in arbitrary locations without local protection. Furthermore, we investigate also how the protected aperture can be improved using a specially matched phase advance between dump kickers and the tertiary collimators, as was don...
The effect of explosion parameters on seismic source wavelet calculation and its characteristics
Yimin, Wang; Gang, Tian; Luyang, Yu
2017-10-01
This paper focuses on the calculation and analysis of the source wavelet produced by explosions in land seismic exploration, in order to reveal the effect of the explosion parameters on the signal features of seismic records. The calculation process consist of three steps, numerical simulation of explosions in rock and soil, plastic-elastic boundary (PEB) pressure curve fitting and application of the spherical source model. Four groups of explosion parameters are considered, including detonation velocity, charge weight, coupling material and geometry coupling. The study shows that the source wavelets of limestone and sandstone lack of energy in the low frequency range, which can be enlarged by applying a high detonation velocity explosive, a large charge weight and water coupling. The main frequency of source wavelet of loess is relatively low, which can be increased by using a low detonation velocity explosive and a small charge weight. The result is consistent with the field observations and can serve as a guide for selecting the explosion parameters.
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Brdar Mirjana M.
2011-01-01
Full Text Available The adsorption of Cu(II onto poplar sawdust as an adsorbent is analyzed. The experimental data were fitted by the Langmuir isotherm using four linearized forms at the isotherm along with the original one. The least squares regression method was applied. Using the obtained Langmuir constants by each at methods, the enthalpy, entropy and Gibbs free energy at adsoption were calculated. A comparison of the used linear and non-linear regression methods in view at the goodness of the fit is presented. The coefficient of correlation was adopted as a criterionn to select the best method. The impact of the choice at regression model on the resulting estimates of the thermodynamic parameters is discussed. The best fit of the experimental data is obtained by the nonlinear regression. Thus, it is recommended to use the Langmuir parameters calculated by the nonlinear regression for estimating the thermodynamic parameters of adsorptin. The differences in the values obtained by different models are not so large to change the basic conclusion that the adsorption of copper ions on poplar sawdust is a spontaneous endothermic process i.e. that tested adsorbent has an affinity for copper ions.
Calculation of Spectral Parameters for Doped/Codoped MWO4 (M = Ba2+/Ca2+) Phosphors
Ambast, A. K.; Sharma, S. K.
2017-08-01
We report the spectral parameters of Dy3+-doped and Sr2+/K+-codoped MWO4 (M = Ba2+/Ca2+) tungstate phosphors synthesized by solid-state reaction route. The structural and optical properties were investigated by x-ray diffraction (XRD) analysis, photoluminescence (PL) measurements, and ultraviolet-visible-near infrared spectroscopy. The XRD results indicate tetragonal structure of the phosphors in space group I4 1 / a. The PL spectra show blue and yellow emission at 489 nm and 577 nm, respectively, on excitation at wavelength of 350 nm. The diffuse reflectance spectra reveal bandgap values for the phosphors in the range from 4.24 eV to 5.7 eV. Judd-Ofelt theory was used to calculate the oscillator strength from the excitation spectra of the phosphors. The intensity parameters ( Ω 2, Ω 4, and Ω 6) were used to calculate many radiative parameters such as the radiative transition probabilities ( A R), radiative lifetime ( τ R), branching ratio ( β R), stimulated emission cross-section [ σ( λ p)], and quantum efficiency ( η) for certain excited states of Dy3+ ion.
Bayesian inference of biochemical kinetic parameters using the linear noise approximation
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Finkenstädt Bärbel
2009-10-01
Full Text Available Abstract Background Fluorescent and luminescent gene reporters allow us to dynamically quantify changes in molecular species concentration over time on the single cell level. The mathematical modeling of their interaction through multivariate dynamical models requires the deveopment of effective statistical methods to calibrate such models against available data. Given the prevalence of stochasticity and noise in biochemical systems inference for stochastic models is of special interest. In this paper we present a simple and computationally efficient algorithm for the estimation of biochemical kinetic parameters from gene reporter data. Results We use the linear noise approximation to model biochemical reactions through a stochastic dynamic model which essentially approximates a diffusion model by an ordinary differential equation model with an appropriately defined noise process. An explicit formula for the likelihood function can be derived allowing for computationally efficient parameter estimation. The proposed algorithm is embedded in a Bayesian framework and inference is performed using Markov chain Monte Carlo. Conclusion The major advantage of the method is that in contrast to the more established diffusion approximation based methods the computationally costly methods of data augmentation are not necessary. Our approach also allows for unobserved variables and measurement error. The application of the method to both simulated and experimental data shows that the proposed methodology provides a useful alternative to diffusion approximation based methods.
A new methodology to determine kinetic parameters for one- and two-step chemical models
Mantel, T.; Egolfopoulos, F. N.; Bowman, C. T.
1996-01-01
In this paper, a new methodology to determine kinetic parameters for simple chemical models and simple transport properties classically used in DNS of premixed combustion is presented. First, a one-dimensional code is utilized to performed steady unstrained laminar methane-air flame in order to verify intrinsic features of laminar flames such as burning velocity and temperature and concentration profiles. Second, the flame response to steady and unsteady strain in the opposed jet configuration is numerically investigated. It appears that for a well determined set of parameters, one- and two-step mechanisms reproduce the extinction limit of a laminar flame submitted to a steady strain. Computations with the GRI-mech mechanism (177 reactions, 39 species) and multicomponent transport properties are used to validate these simplified models. A sensitivity analysis of the preferential diffusion of heat and reactants when the Lewis number is close to unity indicates that the response of the flame to an oscillating strain is very sensitive to this number. As an application of this methodology, the interaction between a two-dimensional vortex pair and a premixed laminar flame is performed by Direct Numerical Simulation (DNS) using the one- and two-step mechanisms. Comparison with the experimental results of Samaniego et al. (1994) shows a significant improvement in the description of the interaction when the two-step model is used.
A New Efficient Method for Calculation of Frenkel Exciton Parameters in Molecular Aggregates
Plötz, Per-Arno; Kühn, Oliver
2013-01-01
The Frenkel exciton Hamiltonian is at the heart of many simulations of excitation energy transfer in molecular aggregates. It separates the aggregate into Coulomb-coupled monomers. Here it is shown that the respective parameters, i.e. monomeric excitation energies and Coulomb couplings between transition densities, can be efficiently calculated using time-dependent tight-binding-based density functional theory (TD-DFTB). Specifically, Coulomb couplings are expressed in terms of self-consistently determined Mulliken transition charges. The determination of the sign of the coupling requires an additional super-molecule calculation. The approach is applied to two dimer systems. First, formaldehyde oxime for which a detailed comparison with standard DFT using the B3LYP and the PBE functionals is provided. Second, the Coulomb coupling is explored in dependence on the intermolecular coordinates for a perylene bisimide dimer. This provides structural evidence for the previously observed biphasic aggregation behavior...
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Saniso, E.
2007-05-01
Full Text Available The objectives of this research were to study basic physical parameters of three agricultural residues that could be used for prediction of paddy drying kinetics using desiccants, to investigate a suitable methodfor moisture reduction of fresh paddy using 3 absorbents, and to modify the drying model of Inoue et al. for determining the evolution of moisture transfer during the drying period. Rice husk, sago palm rachis andcoconut husk were used as moisture desiccants in these experiments. From the results, it was concluded that the apparent density of all adsorbents was a linear function of moisture content whilst an equilibriummoisture content equation following Hendersonís model gave the best fit to the experimental results. From studying the relationship between moisture ratio and drying time under the condition of drying temperaturesof 30, 50 and 70oC, air flow rate of 1.6 m/s and initial moisture content of absorbents of 15, 20 and 27% dry-basis, it was shown that the moisture ratio decreased when drying time increased. In addition, thethin-layer desiccant drying equation following of the Page model can appropriately explain the evolution of moisture content of paddy over the drying time. The diffusion coefficient of all absorbents, which was in therange of 1x10-8 to 6x10-8 m2/h, was relatively dependent on drying temperature and inversely related to drying time. The diffusivity of coconut husk had the highest value compared to the other absorbents.The simulating modified mathematical model to determine drying kinetics of paddy using absorption technique and the simulated results had good relation to the experimental results for all adsorbents.
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Zakharchenko A. A.
2008-06-01
Full Text Available A method of fast determination of the high resistivity detector charge collection parameters with the use of the detector dosimetric characteristics and by means of mathematical simulation is proposed. A problem of calculation of charge collection parameters is investigated for planar gamma-radiation dosimetric detectors made from semi-insulating compound semiconductor CdTe (CdZnTe. An applicability of the considered method is verified by computer simulation for HgI2 gamma-radiation detectors. The considered method can be used in the development of both dosimetry and spectrometry devices for radiation monitoring and for monitoring of characteristic devices operating in hard radiation fields. KEY WORDS: mobility, life time, semiconductor detectors, semi-insulating semiconductors, CdTe, CdZnTe, HgI2, Monte-Carlo method.
Mathematical calculation model for geometrical parameters of timber mesh design with orthogonal grid
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Loktev Dmitriy Aleksandrovich
Full Text Available Mesh cover design, a multi-element design, which ensures the correct geometrical arrangement of the elements, is a very important task. The purpose of the given article is the development of a mathematical model for selecting the geometric parameters of wooden arches with mesh orthogonal grid with different input data. In this article three variants of design were observed. The main differences between them are in the relative position of longitudinal and transverse components. When performing static calculations of such designs in order to achieve their subsequent correct assembly, the following location conditions were observed: all the items must strictly match with each other without a gap and without overlap. However, these conditions must be met for any ratio of height to the arch span, the number of longitudinal members and the thickness of longitudinal members. Inverse problems also take place. In this case, the geometric calculation is not possible to vary the cross-section elements, and the stress-strain state of the cover is provided by varying the pitch of the transverse arches of the elements, on which the geometric calculation has no influence. All this determines the need for universal mathematical models describing any geometrical parameter of the designs needed for their geometrical calculation. The basic approach for the development of such models is the use of the known trigonometric formulas, giving a complete description of the desired geometry of the arch. Finally three transcendental equations were obtained, the solution algorithm of which using Newton’s method is presented in the MathCAD. The complexity of solving such equations using the proposed algorithm in the MathCAD is reduced to a minimum.
A multigrid method for drift-kinetic calculations in stellarators and rippled tokamaks
Landreman, Matt; Smith, Håkan
2017-10-01
Important phenomena such as the bootstrap current and collisional transport in stellarators, and neoclassical toroidal viscosity in tokamaks, must be computed by numerical solution of the drift-kinetic equation in nonaxisymmetric geometry. This equation has the form of a linear, inhomogeneous, advection-dominated advection-diffusion PDE with recirculating flow, internal boundary layers, and a null space, with typically five coupled dimensions (poloidal and toroidal angle, speed, velocity pitch angle, and species.) While multigrid algorithms are a preferred method for efficient solution of some PDEs, multigrid smoothers are typically unstable for accurate discretizations of the drift-kinetic equation due to the absence of any physical diffusion in the spatial dimensions, and the dominance of advection over diffusion in the velocity dimensions. In this work we demonstrate a high-order-accurate multigrid solution of the drift-kinetic equation in nonaxisymmetric geometry. A defect correction approach is used: solution of a high-order discretized problem is preconditioned by a multigrid cycle in which a low-order upwinded discretization is used for smoothing. Compared to a direct solver, the multigrid method can reduce the memory requirement by several orders of magnitude. Supported by US DoE FES award DE-FG02-93ER54197.
Computer controlled automated assay for comprehensive studies of enzyme kinetic parameters.
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Felix Bonowski
Full Text Available Stability and biological activity of proteins is highly dependent on their physicochemical environment. The development of realistic models of biological systems necessitates quantitative information on the response to changes of external conditions like pH, salinity and concentrations of substrates and allosteric modulators. Changes in just a few variable parameters rapidly lead to large numbers of experimental conditions, which go beyond the experimental capacity of most research groups. We implemented a computer-aided experimenting framework ("robot lab assistant" that allows us to parameterize abstract, human-readable descriptions of micro-plate based experiments with variable parameters and execute them on a conventional 8 channel liquid handling robot fitted with a sensitive plate reader. A set of newly developed R-packages translates the instructions into machine commands, executes them, collects the data and processes it without user-interaction. By combining script-driven experimental planning, execution and data-analysis, our system can react to experimental outcomes autonomously, allowing outcome-based iterative experimental strategies. The framework was applied in a response-surface model based iterative optimization of buffer conditions and investigation of substrate, allosteric effector, pH and salt dependent activity profiles of pyruvate kinase (PYK. A diprotic model of enzyme kinetics was used to model the combined effects of changing pH and substrate concentrations. The 8 parameters of the model could be estimated from a single two-hour experiment using nonlinear least-squares regression. The model with the estimated parameters successfully predicted pH and PEP dependence of initial reaction rates, while the PEP concentration dependent shift of optimal pH could only be reproduced with a set of manually tweaked parameters. Differences between model-predictions and experimental observations at low pH suggest additional protonation
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Ruth Alfaro-Cuevas-Villanueva
2014-01-01
Full Text Available The sorption of cadmium (Cd and lead (Pb by calcium alginate beads (CAB from aqueous solutions in batch systems was investigated. The kinetic and thermodynamic parameters, as well as the sorption capacities of CAB in each system at different temperatures, were evaluated. The rate of sorption for both metals was rapid in the first 10 minutes and reached a maximum in 50 minutes. Sorption kinetic data were fitted to Lagergren, pseudo-second-order and Elovich models and it was found that the second-order kinetic model describes these data for the two metals; comparing kinetic parameters for Cd and Pb sorption a higher kinetic rate (K2 for Pb was observed, indicating that the interaction between lead cations and alginate beads was faster than for cadmium. Similarly, isotherm data were fitted to different models reported in literature and it was found that the Langmuir-Freundlich (L-F and Dubinin-Radushkevich (D-R models describe the isotherms in all cases. CAB sorption capacity for cadmium was 27.4 mg/g and 150.4 mg/g for lead, at 25°C. Sorption capacities of Cd and Pb increase as temperature rises. According to the thermodynamic parameters, the cadmium and lead adsorption process was spontaneous and endothermic. It was also found that pH has an important effect on the adsorption of these metals by CAB, as more were removed at pH values between 6 and 7.
Alfaro-Cuevas-Villanueva, Ruth; Hidalgo-Vázquez, Aura Roxana; Cortés Penagos, Consuelo de Jesús; Cortés-Martínez, Raúl
2014-01-01
The sorption of cadmium (Cd) and lead (Pb) by calcium alginate beads (CAB) from aqueous solutions in batch systems was investigated. The kinetic and thermodynamic parameters, as well as the sorption capacities of CAB in each system at different temperatures, were evaluated. The rate of sorption for both metals was rapid in the first 10 minutes and reached a maximum in 50 minutes. Sorption kinetic data were fitted to Lagergren, pseudo-second-order and Elovich models and it was found that the second-order kinetic model describes these data for the two metals; comparing kinetic parameters for Cd and Pb sorption a higher kinetic rate (K 2) for Pb was observed, indicating that the interaction between lead cations and alginate beads was faster than for cadmium. Similarly, isotherm data were fitted to different models reported in literature and it was found that the Langmuir-Freundlich (L-F) and Dubinin-Radushkevich (D-R) models describe the isotherms in all cases. CAB sorption capacity for cadmium was 27.4 mg/g and 150.4 mg/g for lead, at 25°C. Sorption capacities of Cd and Pb increase as temperature rises. According to the thermodynamic parameters, the cadmium and lead adsorption process was spontaneous and endothermic. It was also found that pH has an important effect on the adsorption of these metals by CAB, as more were removed at pH values between 6 and 7. PMID:24587740
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B. Likozar
2012-09-01
Full Text Available Mathematical models for a batch process were developed to predict concentration distributions for an active ingredient (vancomycin adsorption on a representative hydrophobic-molecule adsorbent, using differently diluted crude fermentation broth with cells as the feedstock. The kinetic parameters were estimated using the maximization of the coefficient of determination by a heuristic algorithm. The parameters were estimated for each fermentation broth concentration using four concentration distributions at initial vancomycin concentrations of 4.96, 1.17, 2.78, and 5.54 g l−¹. In sequence, the models and their parameters were validated for fermentation broth concentrations of 0, 20, 50, and 100% (v/v by calculating the coefficient of determination for each concentration distribution at the corresponding initial concentration. The applicability of the validated models for process optimization was investigated by using the models as process simulators to optimize the two process efficiencies.
Mukundan, Vrinda; Bhardwaj, Anil
2018-01-01
A one dimensional photochemical model for the dayside ionosphere of Titan has been developed for calculating the density profiles of ions and electrons under steady state photochemical equilibrium condition. We concentrated on the T40 flyby of Cassini orbiter and used the in-situ measurements from instruments onboard Cassini as input to the model. An energy deposition model is employed for calculating the attenuated photon flux and photoelectron flux at different altitudes in Titan's ionosphere. We used the Analytical Yield Spectrum approach for calculating the photoelectron fluxes. Volume production rates of major primary ions, like, N2+, N+ , CH4+, CH3+, etc due to photon and photoelectron impact are calculated and used as input to the model. The modeled profiles are compared with the Cassini Ion Neutral Mass Spectrometer (INMS) and Langmuir Probe (LP) measurements. The calculated electron density is higher than the observation by a factor of 2 to 3 around the peak. We studied the impact of different model parameters, viz. photoelectron flux, ion production rates, electron temperature, dissociative recombination rate coefficients, neutral densities of minor species, and solar flux on the calculated electron density to understand the possible reasons for this discrepancy. Recent studies have shown that there is an overestimation in the modeled photoelectron flux and N2+ ion production rates which may contribute towards this disagreement. But decreasing the photoelectron flux (by a factor of 3) and N2+ ion production rate (by a factor of 2) decreases the electron density only by 10 to 20%. Reduction in the measured electron temperature by a factor of 5 provides a good agreement between the modeled and observed electron density. The change in HCN and NH3 densities affects the calculated densities of the major ions (HCNH+ , C2H5+, and CH5+); however the overall impact on electron density is not appreciable ( < 20%). Even though increasing the dissociative
Calculating wave-generated bottom orbital velocities from surface-wave parameters
Wiberg, P.L.; Sherwood, C.R.
2008-01-01
Near-bed wave orbital velocities and shear stresses are important parameters in many sediment-transport and hydrodynamic models of the coastal ocean, estuaries, and lakes. Simple methods for estimating bottom orbital velocities from surface-wave statistics such as significant wave height and peak period often are inaccurate except in very shallow water. This paper briefly reviews approaches for estimating wave-generated bottom orbital velocities from near-bed velocity data, surface-wave spectra, and surface-wave parameters; MATLAB code for each approach is provided. Aspects of this problem have been discussed elsewhere. We add to this work by providing a method for using a general form of the parametric surface-wave spectrum to estimate bottom orbital velocity from significant wave height and peak period, investigating effects of spectral shape on bottom orbital velocity, comparing methods for calculating bottom orbital velocity against values determined from near-bed velocity measurements at two sites on the US east and west coasts, and considering the optimal representation of bottom orbital velocity for calculations of near-bed processes. Bottom orbital velocities calculated using near-bed velocity data, measured wave spectra, and parametric spectra for a site on the northern California shelf and one in the mid-Atlantic Bight compare quite well and are relatively insensitive to spectral shape except when bimodal waves are present with maximum energy at the higher-frequency peak. These conditions, which are most likely to occur at times when bottom orbital velocities are small, can be identified with our method as cases where the measured wave statistics are inconsistent with Donelan's modified form of the Joint North Sea Wave Project (JONSWAP) spectrum. We define the 'effective' forcing for wave-driven, near-bed processes as the product of the magnitude of forcing times its probability of occurrence, and conclude that different bottom orbital velocity statistics
METHODOLOGY FOR HYDRAULIC CALCULATION OF RIVER REGULATION AND DETERMINATION OF DIKE PARAMETERS
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E. I. Mikhnevich
2017-01-01
Full Text Available Territory protection against flood water inundation and creation of polder systems are carried out with the help of protection dikes. One of the main requirements to the composition of polder systems in flood plains is a location of border dikes beyond meander belt in order to avoid their erosion when meander development occurs. Meander belt width can be determined on the basis of the analysis of multi-year land surveying pertaining top river-bed building and in the case when such data is not available this parameter is calculated in accordance with the Snishchenko formula. While banking-up a river bed a flooded area is decreasing and, consequently, water level in inter-dike space and rate of flood water are significantly increasing. For this reason it is necessary to locate dikes at a such distance from a river bed which will not cause rather high increase in water level and flow velocity in the inter-dike space. Methodology for hydraulic calculation of river regulation has been developed in order to substantiate design parameters for levee systems, creation of favourable hydraulic regime in these systems and provision of sustainability for dikes. Its main elements are calculations of pass-through capacity of the leveed channel and rise of water level in inter-dike space, and distance between dikes and their crest level. Peculiar feature of the proposed calculated formulae is an interaction consideration of channel and inundated flows. Their mass-exchanging process results in slowing-down of the channel flow and acceleration of the inundated flow. This occurrence is taken into account and coefficients of kinematic efficiency are introduced to the elements of water flow rate in the river channel and flood plain, respectively. The adduced dependencies for determination of a dike crest level (consequently their height take into consideration a rise of water level in inter-dike space for two types of polder systems: non-inundable (winter dikes with
Importance of variable time-step algorithms in spatial kinetics calculations
Energy Technology Data Exchange (ETDEWEB)
Aviles, B.N.
1994-12-31
The use of spatial kinetics codes in conjunction with advanced thermal-hydraulics codes is becoming more widespread as better methods and faster computers appear. The integrated code packages are being used for routine nuclear power plant design and analysis, including simulations with instrumentation and control systems initiating system perturbations such as rod motion and scrams. As a result, it is important to include a robust variable time-step algorithm that can accurately and efficiently follow widely varying plant neutronic behavior. This paper describes the variable time-step algorithm in SPANDEX and compares the automatic time-step scheme with a more traditional fixed time-step scheme.
DEFF Research Database (Denmark)
Rolsted, Kamilla; Rapin, Nicolas; Steffansen, Bente
2011-01-01
Substances that compete for the same saturable intestinal transporters may when dosed together lead to altered permeability and hence influence bioavailability. The aim was to simulate kinetic parameters, i.e. K(m) and J(max), for transporter mediated E(1)S permeability across Caco-2 cells...
QUALITY, PERFORMANCE ANALYSIS, MASS TRANSFER PARAMETERS AND MODELING OF DRYING KINETICS OF SOYBEAN
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H. Darvishi
Full Text Available Abstract Different aspects of soybean drying such as energy and exergy analyses, quality, mass transfer parameters, and modeling of drying kinetics were investigated in a microwave dryer. Results showed that energy and exergy efficiency increased with increasing microwave power, while values of energy efficiency (33.70 to 66.0% were higher than exergy efficiency (23.38 - 48.30%. Specific energy consumption and energy loss varied 4.93 to 9.11 MJ/kg water and 5.04 to 8.89 MJ/kg water, respectively. Approximately 8.94 to 20.07% of the total energy input is consumed by increasing of the product temperature. The values of improvement potential changed between 1.31- 5.35 MJ/kg water. Bulk density, degree of shrinkage and rehydration ratio varied from 726.6 to 762.8 kg/m3, 0.888 to 0.910, and 0.618 - 0.799, respectively. Parameters total color change (14.68 - 19. 89 and hue angle (88.07 to 91.73º increased with increasing microwave power. Effective diffusivity and mass transfer coefficient varied from 1.99×10−9 to 12.25×10−9 m2/s and 2.71×10−6 to 19.98×10−6 m/s, respectively. The activation energy was found to be 4.98 W/g for a diffusion model and 5.33 W/g for a mass transfer model. Among the models, the Page model was found to best describe the drying behavior of soybean.
Xing, Zhi L; Zhao, Tian T; Gao, Yan H; Yang, Xu; Liu, Shuai; Peng, Xu Y
2017-02-23
Changing of CH4 oxidation potential and biological characteristics with CH4 concentration was studied in a landfill cover soil reactor (LCSR). The maximum rate of CH4 oxidation reached 32.40 mol d-1 m-2 by providing sufficient O2 in the LCSR. The kinetic parameters of methane oxidation in landfill cover soil were obtained by fitting substrate diffusion and consumption model based on the concentration profile of CH4 and O2. The values of [Formula: see text] (0.93-2.29%) and [Formula: see text] (140-524 nmol kgsoil-DW-1·s-1) increased with CH4 concentration (9.25-20.30%), while the values of [Formula: see text] (312.9-2.6%) and [Formula: see text] (1.3 × 10-5 to 9.0 × 10-3 nmol mL-1 h-1) were just the opposite. MiSeq pyrosequencing data revealed that Methylobacter (the relative abundance was decreased with height of LCSR) and Methylococcales_unclassified (the relative abundance was increased expect in H 80) became the key players after incubation with increasing CH4 concentration. These findings provide information for assessing CH4 oxidation potential and changing of biological characteristics in landfill cover soil.
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Claudio Milton Montenegro Campos
2014-10-01
Full Text Available This study evaluated the treatment of wastewater from coffee wet processing (WCWP in an anaerobic treatment system at a laboratory scale. The system included an acidification/equalization tank (AET, a heat exchanger, an Upflow Anaerobic Sludge Blanket Reactor (UASB, a gas equalization device and a gas meter. The minimum and maximum flow rates and volumetric organic loadings rate (VOLR were 0.004 to 0.037 m 3 d -1 and 0.14 to 20.29 kgCOD m -3 d -1 , respectively. The kinetic parameters measured during the anaerobic biodegradation of the WCWP, with a minimal concentration of phenolic compounds of 50 mg L - ¹, were: Y = 0.37 mgTVS (mgCODremoved -1 , Kd = 0.0075 d-1 , Ks = 1.504mg L -1 , μmax = 0.2 d -1 . The profile of sludge in the reactor showed total solids (TS values from 22,296 to 55,895 mg L -1 and TVS 11,853 to 41,509 mg L -1 , demonstrating a gradual increase of biomass in the reactor during the treatment, even in the presence of phenolic compounds in the concentration already mentioned.
Adsorption kinetic parameters of Fe3+ and Ni2+ ions by gyrolite
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Kestutis Baltakys
2015-03-01
Full Text Available In this work the adsorption kinetic parameters for Fe3+ and Ni2+ ions by gyrolite are presented. Additionally, the adsoption mechanism was described by using pseudo first order and pseudo second order equations. It was determined that the adsorption capacity of gyrolite and intrusion of heavy metals ions in its structure depends on reaction time and the pH value of adsorptive. It was observed that the incorporation of Fe3+ ions occurs more intensive than Ni2+ ions. It was found that in the acidic solution the intrusion of Fe3+ ions into gyrolite structure proceeds by two types of chemical reaction mechanisms: substitution and addition. Meanwhile, nickel ions were participated only in substitution reaction: gyrolite-Ca0 + Mex+ ↔ gyrolite-Me0 + Ca2+. It was observed that the pseudo second order model fit well for iron and nickel ions adsorption mechanism. It was estimated that the adsorption reactions are not reversible process and the crystal structure of gyrolite is stable. Moreover, synthetic adsorbent and the products of sorption were characterized by XRD, STA and FT-IR methods.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5735
Chen, Dengyu; Zhou, Jianbin; Zhang, Qisheng
2014-10-01
Effects of heating rate on slow pyrolysis behaviors, kinetic parameters, and products properties of moso bamboo were investigated in this study. Pyrolysis experiments were performed up to 700 °C at heating rates of 5, 10, 20, and 30 °C/min using thermogravimetric analysis (TGA) and a lab-scale fixed bed pyrolysis reactor. The results show that the onset and offset temperatures of the main devolatilization stage of thermogravimetry/derivative thermogravimetry (TG/DTG) curves obviously shift toward the high-temperature range, and the activation energy values increase with increasing heating rate. The heating rate has different effects on the pyrolysis products properties, including biochar (element content, proximate analysis, specific surface area, heating value), bio-oil (water content, chemical composition), and non-condensable gas. The solid yields from the fixed bed pyrolysis reactor are noticeably different from those of TGA mainly because the thermal hysteresis of the sample in the fixed bed pyrolysis reactor is more thorough. Copyright © 2014 Elsevier Ltd. All rights reserved.
Directory of Open Access Journals (Sweden)
D. E. Panayotounakos
2002-01-01
Full Text Available We present the construction of the general solutions concerning the one-dimensional (1D fully dynamic nonlinear partial differential equations (PDEs, for the erosion kinetics. After an uncoupling procedure of the above mentioned equations a second–order nonlinear PDE of the Monge type governing the porosity is derived, the general solution of which is constructed in the sense that a full complement of arbitrary functions (as many as the order is introduced. Afterwards, we specify the above solution according to convenient initial conditions.
Cáceres, Lizethly; Escudey, Mauricio; Fuentes, Edwar; Báez, María E
2010-07-15
Metsulfuron-methyl sorption kinetic was studied in Andisol and Ultisol soils in view of their distinctive physical and chemical properties: acidic pH and variable surface charge. Different kinetic models were applied to the experimental results. The pseudo-second-order model fitted sorption kinetics data better than the pseudo-first-order model. The rate constant and the initial rate constant values obtained through this model demonstrated the different behavior of metsulfuron-methyl in both kinds of soils, both parameters being the highest for Andisol. The application of Elovich equation, intraparticle diffusion model and a two-site nonequilibrium model (TSNE) allowed to conclude that: (i) the high organic matter content is the governing factor for Andisols where mass transfer across the boundary layer, and in a lesser degree, intraparticle diffusion were the two processes controlling sorption kinetic and (ii) the mineral composition was more relevant in Ultisols where rate was controlled almost exclusively by intraparticle diffusion into macropores and micropores. The slower sorption rate on Ultisols, the mechanism involved and the lower sorption capacity of this kind of soils must be taken into account to assess leaching behavior of this herbicide. 2010 Elsevier B.V. All rights reserved.
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Juliana Cristina de Castro Budel
2017-06-01
Full Text Available The inclusion effect of 0 (control, 15, 30, 45, 60, and 100% dry matter (DM of Brazil nut (Bertholletia excelsa Bonpl. cake (BNC aiming at replacing corn silage was assessed on fermentation kinetics and effective degradability (ED by means of in vitro gas production at 3, 6, 9, 12, 24, 48, 72 and 96 h. A randomized block design was used with six treatments, three blocks, and two replications per block. France’s model was fit to the data. An in vivo experiment, conducted in fistulated ovine, assessed the effects of BNC inclusion levels of 0, 15, 30, and 45% DM replacing corn silage on ruminal parameters. Ruminal fluid samples were collected postprandial at 8, 10, 12, 14, 16, and 18 h for determining the concentrations of short-chain fatty acids (SCFA, pH, and N–NH3. A completely randomized design with repeated measures in time was used, with four treatments and three replications. Results of acetate, propionate, butyrate, acetate to propionate ratio, pH, and NH3 were submitted to analysis of variance and regression (linear and quadratic considering treatment, time and interaction of both. In addition, the F test with a 5% (P 0.40, acetic acid (P > 0.41, propionic acid (P > 0.85, butyric acid (P > 0.62 and pH (P > 0.57. BNC replacements of 0, 15, 30 and 45% did not change (P > 0.05 total SCFA concentration, as well as acetic acid concentration in ovine. When including 45% DM of BNC, concentrations (mMol/100 mL of propionic (P < 0.001 and butyric (P < 0.022 acids was reduced in the ruminal fluid. The highest concentrations at measurement times were observed 4 hours after feeding. The pH values presented a quadratic effect on both inclusion (P < 0.001 and time (P < 0.001. An interaction was observed between treatment and time for N–NH3 concentration (mg/ml (P < 0.001 and acetic to propionic acids ratio (P < 0.014. Fermentation kinetics was negatively affected by Brazil nut cake inclusion to corn silage-based diet. Therefore, the use of this
Ben Mosbah, Abdallah
In order to improve the qualities of wind tunnel tests, and the tools used to perform aerodynamic tests on aircraft wings in the wind tunnel, new methodologies were developed and tested on rigid and flexible wings models. A flexible wing concept is consists in replacing a portion (lower and/or upper) of the skin with another flexible portion whose shape can be changed using an actuation system installed inside of the wing. The main purpose of this concept is to improve the aerodynamic performance of the aircraft, and especially to reduce the fuel consumption of the airplane. Numerical and experimental analyses were conducted to develop and test the methodologies proposed in this thesis. To control the flow inside the test sections of the Price-Paidoussis wind tunnel of LARCASE, numerical and experimental analyses were performed. Computational fluid dynamics calculations have been made in order to obtain a database used to develop a new hybrid methodology for wind tunnel calibration. This approach allows controlling the flow in the test section of the Price-Paidoussis wind tunnel. For the fast determination of aerodynamic parameters, new hybrid methodologies were proposed. These methodologies were used to control flight parameters by the calculation of the drag, lift and pitching moment coefficients and by the calculation of the pressure distribution around an airfoil. These aerodynamic coefficients were calculated from the known airflow conditions such as angles of attack, the mach and the Reynolds numbers. In order to modify the shape of the wing skin, electric actuators were installed inside the wing to get the desired shape. These deformations provide optimal profiles according to different flight conditions in order to reduce the fuel consumption. A controller based on neural networks was implemented to obtain desired displacement actuators. A metaheuristic algorithm was used in hybridization with neural networks, and support vector machine approaches and their
Ismail, L. F. M.; Emara, M. M.; El-Moselhy, M. M.; Maziad, N. A.; Hussein, O. K.
2014-10-01
Silica-coating ZnO nanoparticles were prepared using the hydrothermal method. The prepared nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray Spectroscopy (EDX). It was found that ultrafine core/shell structured silica-coating ZnO nanoparticles were successfully obtained. TEM analysis revealed a continuous and uniform silica coating layer of about 8 nm in thickness on the surface of ZnO nanoparticles. The photocatalytic performance of silica-coating ZnO core/shell nanoparticles in methylene blue aqueous solution was investigated. The effects of some operational parameters such as pH value, nanocatalyst loading and initial MB concentration on the degradation efficiency were discussed. Kinetic parameters were experimentally determined and a pseudo-first-order kinetic was observed. Thus, the main advantage of the coating is the stability of the photocatalysts and the better performance in acidic or alkaline solutions. Compared to ZnO the maximum apparent rate constant is obtained at pH 8.5 (pH 11.5 in case of bare ZnO). Moreover, the Langmuir adsorption model was applied to describe the equilibrium isotherm at different MB concentration. The applicability of the Langmuir isotherm suggests monolayer coverage of the MB onto surface of silica-coating ZnO nanoparticles. The kinetics of the adsorption with respect to the initial dye concentration, were also investigated. The pseudo-first-order and second-order kinetic models were used and the rate constants were evaluated. The kinetic studies revealed that the pseudo-second-order kinetic model better represented the adsorption kinetics, suggesting that the adsorption process may be chemisorption.
Ismail, L F M; Emara, M M; El-Moselhy, M M; Maziad, N A; Hussein, O K
2014-10-15
Silica-coating ZnO nanoparticles were prepared using the hydrothermal method. The prepared nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray Spectroscopy (EDX). It was found that ultrafine core/shell structured silica-coating ZnO nanoparticles were successfully obtained. TEM analysis revealed a continuous and uniform silica coating layer of about 8nm in thickness on the surface of ZnO nanoparticles. The photocatalytic performance of silica-coating ZnO core/shell nanoparticles in methylene blue aqueous solution was investigated. The effects of some operational parameters such as pH value, nanocatalyst loading and initial MB concentration on the degradation efficiency were discussed. Kinetic parameters were experimentally determined and a pseudo-first-order kinetic was observed. Thus, the main advantage of the coating is the stability of the photocatalysts and the better performance in acidic or alkaline solutions. Compared to ZnO the maximum apparent rate constant is obtained at pH 8.5 (pH 11.5 in case of bare ZnO). Moreover, the Langmuir adsorption model was applied to describe the equilibrium isotherm at different MB concentration. The applicability of the Langmuir isotherm suggests monolayer coverage of the MB onto surface of silica-coating ZnO nanoparticles. The kinetics of the adsorption with respect to the initial dye concentration, were also investigated. The pseudo-first-order and second-order kinetic models were used and the rate constants were evaluated. The kinetic studies revealed that the pseudo-second-order kinetic model better represented the adsorption kinetics, suggesting that the adsorption process may be chemisorption. Copyright © 2014. Published by Elsevier B.V.
Thompson, Anne M.; Stewart, Richard W.
1991-01-01
Random photochemical reaction rates are employed in a 1D photochemical model to examine uncertainties in tropospheric concentrations and thereby determine critical kinetic processes and significant correlations. Monte Carlo computations are used to simulate different chemical environments and their related imprecisions. The most critical processes are the primary photodissociation of O3 (which initiates ozone destruction) and NO2 (which initiates ozone formation), and the OH/methane reaction is significant. Several correlations and anticorrelations between species are discussed, and the ozone/transient OH correlation is examined in detail. One important result of the modeling is that estimates of global OH are generally about 25 percent uncertain, limiting the precision of photochemical models. Techniques for reducing the imprecision are discussed which emphasize the use of species and radical species measurements.
DEFF Research Database (Denmark)
Barrera Figueroa, Salvador; Rasmussen, Knud; Jacobsen, Finn
2009-01-01
Typically, numerical calculations of the pressure, free-field, and random-incidence response of a condenser microphone are carried out on the basis of an assumed displacement distribution of the diaphragm of the microphone; the conventional assumption is that the displacement follows a Bessel...... to this problem is to measure the velocity distribution of the membrane by means of a non-contact method, such as laser vibrometry. The measured velocity distribution can be used together with a numerical formulation such as the boundary element method for estimating the microphone response and other parameters......, e.g., the acoustic center. In this work, such a hybrid method is presented and examined. The velocity distributions of a number of condenser microphones have been determined using a laser vibrometer, and these measured velocity distributions have been used for estimating microphone responses...
Lino, Jéssica B R; Rocha, Eduardo P; Ramalho, Teodorico C
2017-06-15
Quantum computing is the field of science that uses quantum-mechanical phenomena, such as superposition and entanglement, to perform operations on data. The fundamental information unit used in quantum computing is the quantum bit or qubit. It is well-known that quantum computers could theoretically be able to solve problems much more quickly than any classical computers. Currently, the first and still the most successful implementations of quantum information processing (QIP) have been based on nuclear spins in liquids. However, molecules that enable many qubits NMR QIP implementations should meet some conditions: have large chemical shifts and be appropriately dispersed for qubit addressability, appreciable spin-spin coupling between any pair of spins, and a long relaxation time. In this line, benzyldene-2,3-dihydro-1H-[1,3]diphosphole (BDF) derivatives have been theoretically tested for maximizing large chemical shifts, spin-spin coupling, and minimizing the hyperfine coupling constant. Thus, the structures were optimized at the B3LYP/6-311G(d,p) level and showed a significant similarity with the experimental geometrical parameters. The NMR spectroscopic parameters (δ and J) were calculated with six different DFT functionals. The τ-HCTH/6-31G(2d) level is in better agreement with the experimental data of 31 P and 13 C chemical shifts, while PCM-B3LYP/cc-pVDZ level shows a decrease on deviation between calculated and experimental values for P-P and P-C SSCC. The surface response technique was employed to rationalize how the hyperfine constant varies with the chemical shifts and coupling constants values. From our findings, BDF-NO 2 was the best candidate for NMR quantum computations (NMR-QC) among the studied series.
Gahlawat, Geeta; Srivastava, Ashok K
2012-11-01
Polyhydroxybutyrate or PHB is a biodegradable and biocompatible thermoplastic with many interesting applications in medicine, food packaging, and tissue engineering materials. The present study deals with the enhanced production of PHB by Azohydromonas australica using sucrose and the estimation of fundamental kinetic parameters of PHB fermentation process. The preliminary culture growth inhibition studies were followed by statistical optimization of medium recipe using response surface methodology to increase the PHB production. Later on batch cultivation in a 7-L bioreactor was attempted using optimum concentration of medium components (process variables) obtained from statistical design to identify the batch growth and product kinetics parameters of PHB fermentation. A. australica exhibited a maximum biomass and PHB concentration of 8.71 and 6.24 g/L, respectively in bioreactor with an overall PHB production rate of 0.75 g/h. Bioreactor cultivation studies demonstrated that the specific biomass and PHB yield on sucrose was 0.37 and 0.29 g/g, respectively. The kinetic parameters obtained in the present investigation would be used in the development of a batch kinetic mathematical model for PHB production which will serve as launching pad for further process optimization studies, e.g., design of several bioreactor cultivation strategies to further enhance the biopolymer production.
Mulyani, Happy; Budianto, Gregorius Prima Indra; Margono, Kaavessina, Mujtahid
2018-02-01
The present investigation deals with the aerobic sequencing batch reactor system of tapioca wastewater treatment with varying pH influent conditions. This project was carried out to evaluate the effect of pH on kinetics parameters of system. It was done by operating aerobic sequencing batch reactor system during 8 hours in many tapioca wastewater conditions (pH 4.91, pH 7, pH 8). The Chemical Oxygen Demand (COD) and Mixed Liquor Volatile Suspended Solids (MLVSS) of the aerobic sequencing batch reactor system effluent at steady state condition were determined at interval time of two hours to generate data for substrate inhibition kinetics parameters. Values of the kinetics constants were determined using Monod and Andrews models. There was no inhibition constant (Ki) detected in all process variation of aerobic sequencing batch reactor system for tapioca wastewater treatment in this study. Furthermore, pH 8 was selected as the preferred aerobic sequencing batch reactor system condition in those ranging pH investigated due to its achievement of values of kinetics parameters such µmax = 0.010457/hour and Ks = 255.0664 mg/L COD.
The High Level Mathematical Models in Calculating Aircraft Gas Turbine Engine Parameters
Directory of Open Access Journals (Sweden)
Yu. A. Ezrokhi
2017-01-01
Full Text Available The article describes high-level mathematical models developed to solve special problems arising at later stages of design with regard to calculation of the aircraft gas turbine engine (GTE under real operating conditions. The use of blade row mathematics models, as well as mathematical models of a higher level, including 2D and 3D description of the working process in the engine units and components, makes it possible to determine parameters and characteristics of the aircraft engine under conditions significantly different from the calculated ones.The paper considers application of mathematical modelling methods (MMM for solving a wide range of practical problems, such as forcing the engine by injection of water into the flowing part, estimate of the thermal instability effect on the GTE characteristics, simulation of engine start-up and windmill starting condition, etc. It shows that the MMM use, when optimizing the laws of the compressor stator control, as well as supplying cooling air to the hot turbine components in the motor system, can significantly improve the integral traction and economic characteristics of the engine in terms of its gas-dynamic stability, reliability and resource.It ought to bear in mind that blade row mathematical models of the engine are designed to solve purely "motor" problems and do not replace the existing models of various complexity levels used in calculation and design of compressors and turbines, because in “quality” a description of the working processes in these units is inevitably inferior to such specialized models.It is shown that the choice of the mathematical modelling level of an aircraft engine for solving a particular problem arising in its designing and computational study is to a large extent a compromise problem. Despite the significantly higher "resolution" and information ability the motor mathematical models containing 2D and 3D approaches to the calculation of flow in blade machine
Monte Carlo code Serpent calculation of the parameters of the stationary nuclear fission wave
Directory of Open Access Journals (Sweden)
V. M. Khotyayintsev
2017-12-01
Full Text Available n this work, propagation of the stationary nuclear fission wave was simulated for series of fixed power values using Monte Carlo code Serpent. The wave moved in the axial direction in 5 m long cylindrical core of fast reactor with pure 238U raw fuel. Stationary wave mode arises some period later after the wave ignition and lasts sufficiently long to determine kef with high enough accuracy. The velocity characteristic of the reactor was determined as the dependence of the wave velocity on the neutron multiplication factor. As we have recently shown within a one-group diffusion description, the velocity characteristic is two-valued due to the effect of concentration mechanisms, while thermal feedback affects it only quantitatively. The shape and parameters of the velocity characteristic critically affect feasibility of the reactor design since stationary wave solutions of the lower branch are unstable and do not correspond to any real waves in self-regulated reactor, like CANDLE. In this work calculations were performed without taking into account thermal feedback. They confirm that theoretical dependence correctly describes the shape of the velocity characteristic calculated using the results of the Serpent modeling.
Jiang, Chao; Qiao, Mingzhong; Zhu, Peng
2017-12-01
A permanent magnet synchronous motor with radial magnetic circuit and built-in permanent magnet is designed for the electric vehicle. Finite element numerical calculation and experimental measurement are adopted to obtain the direct axis and quadrature axis inductance parameters of the motor which are vital important for the motor control. The calculation method is simple, the measuring principle is clear, the results of numerical calculation and experimental measurement are mutual confirmation. A quick and effective method is provided to obtain the direct axis and quadrature axis inductance parameters of the motor, and then improve the design of motor or adjust the control parameters of the motor controller.
Kinetic parameter estimation in N. europaea biofilms using a 2-D reactive transport model.
Lauchnor, Ellen G; Semprini, Lewis; Wood, Brian D
2015-06-01
Biofilms of the ammonia oxidizing bacterium Nitrosomonas europaea were cultivated to study microbial processes associated with ammonia oxidation in pure culture. We explored the hypothesis that the kinetic parameters of ammonia oxidation in N. europaea biofilms were in the range of those determined with batch suspended cells. Oxygen and pH microelectrodes were used to measure dissolved oxygen (DO) concentrations and pH above and inside biofilms and reactive transport modeling was performed to simulate the measured DO and pH profiles. A two dimensional (2-D) model was used to simulate advection parallel to the biofilm surface and diffusion through the overlying fluid while reaction and diffusion were simulated in the biofilm. Three experimental studies of microsensor measurements were performed with biofilms: i) NH3 concentrations near the Ksn value of 40 μM determined in suspended cell tests ii) Limited buffering capacity which resulted in a pH gradient within the biofilms and iii) NH3 concentrations well below the Ksn value. Very good fits to the DO concentration profiles both in the fluid above and in the biofilms were achieved using the 2-D model. The modeling study revealed that the half-saturation coefficient for NH3 in N. europaea biofilms was close to the value measured in suspended cells. However, the third study of biofilms with low availability of NH3 deviated from the model prediction. The model also predicted shifts in the DO profiles and the gradient in pH that resulted for the case of limited buffering capacity. The results illustrate the importance of incorporating both key transport and chemical processes in a biofilm reactive transport model. © 2014 Wiley Periodicals, Inc.
Sadani, Mohsen; Karami, Mohammad Amin; Teimouri, Fahimeh; Amin, Mohammad Mehdi; Moosavi, Seyed Mahdi; Dehdashti, Bahare
2017-10-01
Cleanup of areas contaminated by explosives is a public health concern. Some explosives can be carcinogenic in humans. Pentaerythritol Tetranitrate (PETN), a powerful explosive with very low water solubility, can be easily transported to ground waters. This study was conducted to determine the removal efficiencies of PETN from soil by bioremediation, and obtain kinetic parameters of biological process. This experimental study was conducted at the Environmental Health Engineering Lab (Isfahan University of Medical Sciences, Isfahan, Iran) in 2015-2016. In the present work, bioremediation of the explosive-polluted soils by PETN in anaerobic-aerobic landfarming method was performed. The influence of seeding and biosurfactant addition on bioremediation was also evaluated. The data were analyzed using Microsoft Excel software. The results show that, as the initial concentration of PETN increased, the lag phase was increased and the specific growth rate was increased up to 0.1/day in concentration of 50 mg/kg, and then it was decreased to 0.04/day. Subsequent decreases in specific growth rate can cause substrate inhibition. Seeding causes decrease in lag phase significantly. Biosurfactant addition had little to no impact on the length of lag phase, but biosurfactant plus seeding can increase the growth rate to 0.2/day, however, inhibitory effect of the initial concentration was started in very high concentration of PETN (150 mg/kg). Biosurfactant addition and seeding together have an impressive effect on biodegradation of PETN, furthermore seeding can enhance active microbial consortium and biosurfactant can improve the poor aqueous solubility of PETN, therefore making the substrate more accessible.
A musculoskeletal lumbar and thoracic model for calculation of joint kinetics in the spine
Energy Technology Data Exchange (ETDEWEB)
Kim, Yong Cheol; Ta, Duc manh; Koo, Seung Bum [Chung-Ang University, Seoul (Korea, Republic of); Jung Moon Ki [AnyBody Technology A/S, Aalborg (Denmark)
2016-06-15
The objective of this study was to develop a musculoskeletal spine model that allows relative movements in the thoracic spine for calculation of intra-discal forces in the lumbar and thoracic spine. The thoracic part of the spine model was composed of vertebrae and ribs connected with mechanical joints similar to anatomical joints. Three different muscle groups around the thoracic spine were inserted, along with eight muscle groups around the lumbar spine in the original model from AnyBody. The model was tested using joint kinematics data obtained from two normal subjects during spine flexion and extension, axial rotation and lateral bending motions beginning from a standing posture. Intra-discal forces between spine segments were calculated in a musculoskeletal simulation. The force at the L4-L5 joint was chosen to validate the model's prediction against the lumbar model in the original AnyBody model, which was previously validated against clinical data.
Sheets, Alison L; Corazza, Stefano; Andriacchi, Thomas P
2010-01-01
Accurate subject-specific body segment parameters (BSPs) are necessary to perform kinetic analyses of human movements with large accelerations, or no external contact forces or moments. A new automated topographical image-based method of estimating segment mass, center of mass (CM) position, and moments of inertia is presented. Body geometry and volume were measured using a laser scanner, then an automated pose and shape registration algorithm segmented the scanned body surface, and identified joint center (JC) positions. Assuming the constant segment densities of Dempster, thigh and shank masses, CM locations, and moments of inertia were estimated for four male subjects with body mass indexes (BMIs) of 19.7-38.2. The subject-specific BSP were compared with those determined using Dempster and Clauser regression equations. The influence of BSP and BMI differences on knee and hip net forces and moments during a running swing phase were quantified for the subjects with the smallest and largest BMIs. Subject-specific BSP for 15 body segments were quickly calculated using the image-based method, and total subject masses were overestimated by 1.7-2.9%.When compared with the Dempster and Clauser methods, image-based and regression estimated thigh BSP varied more than the shank parameters. Thigh masses and hip JC to thigh CM distances were consistently larger, and each transverse moment of inertia was smaller using the image-based method. Because the shank had larger linear and angular accelerations than the thigh during the running swing phase, shank BSP differences had a larger effect on calculated intersegmental forces and moments at the knee joint than thigh BSP differences did at the hip. It was the net knee kinetic differences caused by the shank BSP differences that were the largest contributors to the hip variations. Finally, BSP differences produced larger kinetic differences for the subject with larger segment masses, suggesting that parameter accuracy is more
Directory of Open Access Journals (Sweden)
A. N. Ostrikov
2015-01-01
Full Text Available Consumer properties of food raw material formed during the heat treatment. New physical, flavoring and aromatic properties of the products of plant origin, formed during drying due to substantial changes in the composition of the raw materia l occurring as a result of biochemical reactions. In the production of dried and roasted products is very important to follow the parameters that contribute to the passage of biochemical processes aimed at creating a product with high nutritional qualities, strong aroma and pleasant taste. We studied the basic kinetics of the drying process of food raw material (in terms of artichoke in a dense interspersed layer, which formed the basis for the rational choice of the drying regime with due consideration of changes in the moisture content of the product are studied. The nature of the effect of the dried product movement hydrodynamic conditions on a layer height and intensity of drying is established. As a result of food raw material drying process kinetics analysis (in terms of artichoke multistep drying regimes were chosen. Analysis of the artichoke particles drying by air, air-steam mixture and superheated steam intensity showed the presence of two parts: the horizontal one and gradually diminishing one. Kinetic laws of the artichoke drying process in a dense interspersed layer were the basis of engineering calculation of dryer with a transporting body in the form of a "traveling wave". Application of the dryer with the transporting body in the form of a "traveling wave" for food raw material drying allow to achieve uniform drying of the product due to the use of soft, gentle regimes of oversleeping while preserving to the utmost particles of the product; to improve the quality of the finished product through the use of interspersed layer that reduces clumping of product to be dried.
Al Mardini, Fadi; Legube, Bernard
2009-10-30
The application of several monosolute equilibrium models has previously shown that Bromacil adsorption on SA-UF (Norit) powdered activated carbon (PAC) is probably effective on two types of sites. High reactivity sites were found to be 10-20 less present in a carbon surface than lower reactivity sites, according to the q(m) values calculated by isotherm models. The aims of this work were trying, primarily, to identify the kinetic-determinant stage of the sorption of Bromacil at a wide range of initial pesticide concentrations (approximately 5 to approximately 500 microg L(-1) at pH 7.8), and secondly, to specify the rate constants and other useful design parameters for the application in water treatment. It was therefore not possible to specify a priori whether the diffusion or surface reaction is the key step. It shows that many of the tested models which describe the stage of distribution or the surface reaction are correctly applied. However, the diffusivity values (D and D(0)) were found to be constant only constants for some specific experimental concentrations. The HSDM model of surface diffusion in pores was also applied but the values of the diffusion coefficient of surface (D(s)) were widely scattered and reduce significantly with the initial concentration or the equilibrium concentration in Bromacil. The model of surface reaction of pseudo-second order fitted particularly well and led to constant values which are independent of the equilibrium concentration, except for the low concentrations where the constants become significantly more important. This last observation confirms perfectly the hypothesis based on two types of sites as concluded by the equilibrium data (part 1).
Communication: Calculations of the (2 × 1)-O reconstruction kinetics on Cu(110)
Lian, Xin; Xiao, Penghao; Liu, Renlong; Henkelman, Graeme
2017-03-01
Density functional theory calculations are used to study the elementary processes of the formation of the (2 × 1)-O reconstruction on the Cu(110) surface. The (2 × 1)-O reconstruction requires additional Cu atoms to form Cu-O rows on top of the surface. Both terrace and step sites are considered as the source of Cu adatoms. On terraces, adsorbed oxygen induces the ejection of Cu atoms to form -O-Cu-O- units, leaving Cu vacancies behind. The barrier for subsequent unit growth, however, is prohibitively high. Cu(110) step sites are also considered as a source of Cu atoms. Dissociated oxygen triggers the formation of stable Cu-O chains along the [001] step edges. This process, however, blocks the diffusion of Cu atoms so that it is not a viable mechanism for the (2 × 1)-O reconstruction. Oxygen adsorption on the [1 1 ¯ 0 ] edges also allows the nucleation of [001] oriented Cu-O rows. The short Cu-O rows act as diffusion channels for Cu atoms that detach from the step, which append to the end of the Cu-O chains. Our calculations of the formation of the (2 × 1)-O phase on Cu(110) provide a mechanistic description of the experimentally observed reconstruction.
Directory of Open Access Journals (Sweden)
D. A. Gerasimovich
2009-01-01
Full Text Available The paper proposes a calculation method for electromagnetic parameters of single continuously long rod grounding electrode of tubular section at flowing of alternating current of mains frequency into the ground. The method is based on the Maxwell equations. The paper gives a distribution calculation of vertical and radial components of current density using finite differences.
Implications of imprecision in kinetic rate data for photochemical model calculations
Energy Technology Data Exchange (ETDEWEB)
Stewart, R.W.; Thompson, A.M. [National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center
1997-12-31
Evaluation of uncertainties in photochemical model calculations is of great importance to scientists performing assessment modeling. A major source of uncertainty is the measurement imprecision inherent in photochemical reaction rate data that modelers rely on. A rigorous method of evaluating the impact of data imprecision on computational uncertainty is the study of error propagation using Monte Carlo techniques. There are two problems with the current implementation of the Monte Carlo method. First, there is no satisfactory way of accounting for the variation of imprecision with temperature in 1, 2, or 3D models; second, due to its computational expense, it is impractical in 3D model studies. These difficulties are discussed. (author) 4 refs.
Energy Technology Data Exchange (ETDEWEB)
Li, Xifeng; Cai, Zhongli; Katsumura, Yosuke [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab
2000-03-01
The interaction of caffeic acid with e{sub aq}{sup -}, (CH{sub 3}){sub 2}(OH) CCH{sub 2}{sup {center_dot}}, CO{sub 2}{sup {center_dot}}{sup -}, H{sup {center_dot}}, {center_dot}OH and N{sub 3}{sup {center_dot}} radicals were studied by {gamma}-, pulse radiolysis and molecular orbital calculation. UV-visible spectra of electron/{center_dot}OH adducts, semi-quinone radicals of caffeic ions, and the stable products from the reactions were derived. The rate constants were determined. The attacked sites and the most favorable structures of the transient radicals were predicted. Reaction mechanisms were proposed. (author)
Makarycheva, A. I.; Faerman, V. A.
2017-02-01
The analyses of automation patterns is performed and the programming solution for the automation of data processing of the chromatographic data and their further information storage with a help of a software package, Mathcad and MS Excel spreadsheets, is developed. The offered approach concedes the ability of data processing algorithm modification and does not require any programming experts participation. The approach provides making a measurement of the given time and retention volumes, specific retention volumes, a measurement of differential molar free adsorption energy, and a measurement of partial molar solution enthalpies and isosteric heats of adsorption. The developed solution is focused on the appliance in a small research group and is tested on the series of some new gas chromatography sorbents. More than 20 analytes were submitted to calculation of retention parameters and thermodynamic sorption quantities. The received data are provided in the form accessible to comparative analysis, and they are able to find sorbing agents with the most profitable properties to solve some concrete analytic issues.
Kaur, Guneet; Srivastava, Ashok K; Chand, Subhash
2012-09-01
1,3-propanediol (1,3-PD) is a chemical compound of immense importance primarily used as a raw material for fiber and textile industry. It can be produced by the fermentation of glycerol available abundantly as a by-product from the biodiesel plant. The present study was aimed at determination of key kinetic parameters of 1,3-PD fermentation by Clostridium diolis. Initial experiments on microbial growth inhibition were followed by optimization of nutrient medium recipe by statistical means. Batch kinetic data from studies in bioreactor using optimum concentration of variables obtained from statistical medium design was used for estimation of kinetic parameters of 1,3-PD production. Direct use of raw glycerol from biodiesel plant without any pre-treatment for 1,3-PD production using this strain investigated for the first time in this work gave results comparable to commercial glycerol. The parameter values obtained in this study would be used to develop a mathematical model for 1,3-PD to be used as a guide for designing various reactor operating strategies for further improving 1,3-PD production. An outline of protocol for model development has been discussed in the present work.
Energy Technology Data Exchange (ETDEWEB)
David R. Farley
2010-08-19
A model has been developed to calculate the ground-state rotational populations of homonuclear diatomic molecules in kinetic gases, including the effects of electron-impact excitation, wall collisions, and gas feed rate. The equations are exact within the accuracy of the cross sections used and of the assumed equilibrating effect of wall collisions. It is found that the inflow of feed gas and equilibrating wall collisions can significantly affect the rotational distribution in competition with non-equilibrating electron-impact effects. The resulting steady-state rotational distributions are generally Boltzmann for N≥3, with a rotational temperature between the wall and feed gas temperatures. The N=0,1,2 rotational level populations depend sensitively on the relative rates of electron-impact excitation versus wall collision and gas feed rates.
Vázquez, Juana; Harding, Michael E; Stanton, John F; Gauss, Jürgen
2011-05-10
A variational method for the calculation of low-lying vibrational energy levels of molecules with small amplitude vibrations is presented. The approach is based on the Watson Hamiltonian in rectilinear normal coordinates and characterized by a quasi-analytic integration over the kinetic energy operator (KEO). The KEO beyond the harmonic approximation is represented by a Taylor series in terms of the rectilinear normal coordinates around the equilibrium configuration. This formulation of the KEO enables its extension to arbitrary order until numerical convergence is reached for those states describing small amplitude motions and suitably represented with a rectilinear system of coordinates. A Gauss-Hermite quadrature grid representation of the anharmonic potential is used for all the benchmark examples presented. Results for a set of molecules with linear and nonlinear configurations, i.e., CO2, H2O, and formyl fluoride (HFCO), illustrate the performance of the method and the versatility of our implementation.
Van Wey, A S; Cookson, A L; Roy, N C; McNabb, W C; Soboleva, T K; Shorten, P R
2014-11-17
Microorganisms rarely live in isolation but are most often found in a consortium. This provides the potential for cross-feeding and nutrient competition among the microbial species, which make it challenging to predict the growth kinetics in coculture. In this paper we developed a mathematical model to describe substrate consumption and subsequent microbial growth and metabolite production for bacteria grown in monoculture. The model characterized substrate utilization kinetics of 18 Bifidobacterium strains. Some bifidobacterial strains demonstrated preferential degradation of oligofructose in that sugars with low degree of polymerization (DP) (DP≤3 or 4) were metabolized before sugars of higher DP, or vice versa. Thus, we expanded the model to describe the preferential degradation of oligofructose. In addition, we adapted the model to describe the competition between human colonic bacteria Bacteroides thetaiotaomicron LMG 11262 and Bifidobacterium longum LMG 11047 or Bifidobacterium breve Yakult for inulin as well as cross-feeding of breakdown products from the extracellular hydrolysis of inulin by B. thetaiotaomicron LMG 11262. We found that the coculture growth kinetics could be predicted based on the respective monoculture growth kinetics. Using growth kinetics from monoculture experiments to predict coculture dynamics will reduce the number of in vitro experiments required to parameterize multi-culture models. Copyright © 2014 Elsevier B.V. All rights reserved.
Directory of Open Access Journals (Sweden)
Štrbac Nada D.
2015-01-01
Full Text Available The paper presents DTA/TG results of polymetallic sulphide copper concentrate from the mine 'Veliki Krivelj' (Serbia at 25-1000 °C. The reaction mechanism at elevated temperatures was proposed. As confirmation to the proposed mechanism, the results of EDXRF and, XRD analysis of the initial sample and the oxidation products at 550 and 950 °C, and the results of SEM/EDS analysis of the initial sample and the oxidation products at 675 ° C were presented. It can be concluded that the oxidation process goes through sulfide oxidation with characteristic exothermic effects, followed by sulfates and oxy- sulfates formation and their. Kinetic analysis of the oxidation process concentrates the test was performed according to the methods of Kissinger and Ozawa in non-isothermal conditions. The results of kinetic studies have shown that the oxidation process in the whole investigated temperature range is located in the kinetic field.
Gliozzi, T M; Turri, F; Manes, S; Cassinelli, C; Pizzi, F
2017-11-01
Within recent years, there has been growing interest in the prediction of bull fertility through in vitro assessment of semen quality. A model for fertility prediction based on early evaluation of semen quality parameters, to exclude sires with potentially low fertility from breeding programs, would therefore be useful. The aim of the present study was to identify the most suitable parameters that would provide reliable prediction of fertility. Frozen semen from 18 Italian Holstein-Friesian proven bulls was analyzed using computer-assisted semen analysis (CASA) (motility and kinetic parameters) and flow cytometry (FCM) (viability, acrosomal integrity, mitochondrial function, lipid peroxidation, plasma membrane stability and DNA integrity). Bulls were divided into two groups (low and high fertility) based on the estimated relative conception rate (ERCR). Significant differences were found between fertility groups for total motility, active cells, straightness, linearity, viability and percentage of DNA fragmented sperm. Correlations were observed between ERCR and some kinetic parameters, and membrane instability and some DNA integrity indicators. In order to define a model with high relation between semen quality parameters and ERCR, backward stepwise multiple regression analysis was applied. Thus, we obtained a prediction model that explained almost half (R 2=0.47, Pfertility. Once the accuracy of fertility prediction has been confirmed, the model developed in the present study could be used by artificial insemination centers for bull selection or for elimination of poor fertility ejaculates.
Calculation and comparison of circuit breaker parameters in Power World Simulator
National Research Council Canada - National Science Library
Kuljinder Kaur; Er. Simerpreet Singh
2016-01-01
.... In this research work, the different ratings of circuit breaker were calculated. The other objective of this work was comparison between ratings of existing circuit breaker and calculated ratings in POWER WORLD SIMULATOR...
Sato, H; Sato, S; Wang, Y M; Horikoshi, I
1996-06-01
We developed a package of macro programs (named PK_MOMENT) to automatically calculate non-compartmental pharmacokinetic parameters on Microsoft Excel spreadsheets. These macros include rigorous algorithms to execute moment calculations in a comprehensive manner. An optimum number of terminal data points for infinite-time extrapolation can be calculated with one of these macros so that automatic calculation of infinite moment parameters is possible. The moment calculation with PK_MOMENT provided satisfactory results using the hybrid (mixed linear-logarithmic) trapezoidal method rather than the conventional linear trapezoidal method. The macro-aided pharmacokinetic analyses turned out to be useful in that the macro-containing cells can be easily copied and pasted to analyze other data sets and that powerful tools of Excel can be utilized. The use of our macros will be significantly time-saving for routine pharmacokinetic analyses, considering that pharmacokinetic data are usually stored in a spreadsheet format, typically with Excel.
Yang, Yong-Mao; Wang, Ping; Zhang, Yan
2012-04-01
To study the effects of severe acute pancreatitis (SAP) on absorption kinetic parameters of rhubarb free anthraquinones. Eleven healthy Beagle dogs were randomly divided into the normal group (n = 6) and the SAP group (n = 5). The SAP animal model was prepared by surgery through portal vein blood channel building to collect blood from normal dogs and dogs with SAP. The free anthraquinones (20 mg/kg) was given by gastrogavage. The concentrations of five anthraquinones (aloe emodin, rhein, emodin, chrysophanol, and physcion) in the blood plasma of the portal vein and the femoral artery were determined using high performance liquid chromatography (HPLC). The kinetic parameters were calculated using MATLAB2007B Software. The half life (t(1/2Ka)), the absorption peak time (Tmax), the peak concentration (Cmax), the area under the curve [AUC(0-infinity)], and the mean residence time (MRT) were calculated using the statistical moment method. The transport velocity of corresponding medicines from the gastrointestinal tract to the blood (ka) was calculated. There was no difference in the chemical composition absorption type of the portal vein and the femoral artery between the two groups. Aloe emodin could be detected in the portal vein of each animal at each time point, and they were in the quantitative range. Rhein could be detected in the portal vein of each animal at each time point, and they were lower than the quantitative limit at few time points. Emodin and chrysophanol could be detected in the portal vein of partial animals at each time point, and most of them were higher than the quantitative limit. Physcion could be detected only in the portal vein of less animals at few time points. Rhein could be detected in the femoral artery at most time points, but the rhein plasma concentration at most time points were lower than the quantitative limit. Lower concentration of aloe emodin, emodin, and chrysophanol could be detected in the femoral artery at only few time
Directory of Open Access Journals (Sweden)
Beata Urych
2014-01-01
Originality/value: The devolatilization of a homogenous lump of coal is a complex issue. Currently, the CFD technique (Computational Fluid Dynamics is commonly used for the multi-dimensional and multiphase phenomena modelling. The mathematical models, describing the kinetics of the decomposition of coal, proposed in the article can, therefore, be an integral part of models based on numerical fluid mechanics.
Gebben, B.; Mulder, M.H.V.; Smolders, C.A.
1988-01-01
The kinetics of the thermal conversion reaction of poly-(1,3-phenyl-1,4-phenyl)-hydrazide into poly-(1,3-phenyl-1,4-phenyl)-1,3,4-oxadiazole have been studied with isothermal thermogravimetry in continuation of a study with nonisothermal thermogravimetry described in a previous paper. Although the
2004-03-01
Dekkers and Schoonen, 1994; Janzen et al., 2000; Thomas et al., 2001); Realgar (Lengke and Tempel, 2003); and Sphalerite (Weisener et al., 2003...Geochim. Cosmochim. Acta 66, 3281-3291. Lengke M. F. and Tempel R. N. (2003) Natural realgar and amorphous AsS oxidation kinetics. Geochim
Energy Technology Data Exchange (ETDEWEB)
Donskoi, E.; McElwain, D.L.S.; Wibberley, L.J. [Queensland University of Technology, Brisbane, Qld. (Australia). School of Mathematical Science
2003-04-01
The published approaches to the mathematical modeling of rates of reduction, of coal gasification, and of devolatilization of coal in iron/ore coal composites are reviewed and critically analyzed. The effect of different parameters on the overall process is discussed. The concepts of a local rate of reduction and gasification and an integrated rate of reduction are introduced, and the rate-controlling steps in each are reviewed. Current approaches to modeling coal pyrolysis are also described. This review, with the estimates, data, and analysis related to modeling rates of reduction, gasification, and pyrolysis, should prove useful to researchers developing models of coal-based iron ore reduction and related processes.
Rüdt, Matthias; Gillet, Florian; Heege, Stefanie; Hitzler, Julian; Kalbfuss, Bernd; Guélat, Bertrand
2015-09-25
Application of model-based design is appealing to support the development of protein chromatography in the biopharmaceutical industry. However, the required efforts for parameter estimation are frequently perceived as time-consuming and expensive. In order to speed-up this work, a new parameter estimation approach for modelling ion-exchange chromatography in linear conditions was developed. It aims at reducing the time and protein demand for the model calibration. The method combines the estimation of kinetic and thermodynamic parameters based on the simultaneous variation of the gradient slope and the residence time in a set of five linear gradient elutions. The parameters are estimated from a Yamamoto plot and a gradient-adjusted Van Deemter plot. The combined approach increases the information extracted per experiment compared to the individual methods. As a proof of concept, the combined approach was successfully applied for a monoclonal antibody on a cation-exchanger and for a Fc-fusion protein on an anion-exchange resin. The individual parameter estimations for the mAb confirmed that the new approach maintained the accuracy of the usual Yamamoto and Van Deemter plots. In the second case, offline size-exclusion chromatography was performed in order to estimate the thermodynamic parameters of an impurity (high molecular weight species) simultaneously with the main product. Finally, the parameters obtained from the combined approach were used in a lumped kinetic model to simulate the chromatography runs. The simulated chromatograms obtained for a wide range of gradient lengths and residence times showed only small deviations compared to the experimental data. Copyright © 2015 Elsevier B.V. All rights reserved.
DEFF Research Database (Denmark)
Andrade, Thalles Allan; Errico, Massimiliano; Christensen, Knud Villy
2017-01-01
methanolysis rates of glycerides obtained, indicated that transesterification dominates over hydrolysis. The mechanism among the four models proposed that gave the best fit could be simplified, eliminating the kinetic parameters with negligible effects on the reaction rates. This model was able to fit......The use of liquid enzymes for the production of biodiesel as an alternative to chemical catalysts requires significant investigation due to the lack of experimental data for the various feedstock and catalyst combinations. In this paper, reaction rates and kinetic modeling...... the concentration data, four different reaction mechanistic models were compared to determine the mechanism that best fitted the experimental data. Mechanisms where the methanolysis and hydrolysis reactions occurred simultaneously in the system were best at describing the concentration profiles. The high...
Wong, Kin-Yiu; Xu, Yuqing; York, Darrin M
2014-06-30
Detailed understandings of the reaction mechanisms of RNA catalysis in various environments can have profound importance for many applications, ranging from the design of new biotechnologies to the unraveling of the evolutionary origin of life. An integral step in the nucleolytic RNA catalysis is self-cleavage of RNA strands by 2'-O-transphosphorylation. Key to elucidating a reaction mechanism is determining the molecular structure and bonding characteristics of transition state. A direct and powerful probe of transition state is measuring isotope effects on biochemical reactions, particularly if we can reproduce isotope effect values from quantum calculations. This article significantly extends the scope of our previous joint experimental and theoretical work in examining isotope effects on enzymatic and nonenzymatic 2'-O-transphosphorylation reaction models that mimic reactions catalyzed by RNA enzymes (ribozymes), and protein enzymes such as ribonuclease A (RNase A). Native reactions are studied, as well as reactions with thio substitutions representing chemical modifications often used in experiments to probe mechanism. Here, we report and compare results from eight levels of electronic-structure calculations for constructing the potential energy surfaces in kinetic and equilibrium isotope effects (KIE and EIE) computations, including a "gold-standard" coupled-cluster level of theory [CCSD(T)]. In addition to the widely used Bigeleisen equation for estimating KIE and EIE values, internuclear anharmonicity and quantum tunneling effects were also computed using our recently developed ab initio path-integral method, that is, automated integration-free path-integral method. The results of this work establish an important set of benchmarks that serve to guide calculations of KIE and EIE for RNA catalysis. Copyright © 2014 Wiley Periodicals, Inc.
Ahmadinejad, Neda; Tari, Mostafa Talebi
2017-04-01
A density functional theory (DFT) calculations using B3LYP/6-311++G( d,p) method were carried out to investigate the relative stability of the molecules of β-carboline derivatives such as harmaline, harmine, harmalol, harmane and norharmane. Calculated nuclear quadrupole resonance (NQR) parameters were used to determine the 14N nuclear quadrupole coupling constant χ, asymmetry parameter η and EFG tensor ( q zz ). For better understanding of the electronic structure of β-carboline derivatives, natural bond orbital (NBO) analysis, isotropic and anisotropic NMR chemical shieldings were calculated for 14N nuclei using GIAO method for the optimized structures. The NBO analysis shows that pyrrole ring nitrogen (N9) atom has greater tendency than pyridine ring nitrogen (N2) atom to participate in resonance interactions and aromaticity development in the all of these structures. The NMR and NQR parameters were studied in order to find the correlations between electronic structure and the structural stability of the studied molecules.
Comparison of a type curve and a least-squared errors method to estimate biofilm kinetic parameters.
Riefler, R Guy; Smets, Barth F
2003-07-01
Because of the kinetics of diffusion limitation and the difficulty of replicating biofilm structure in a test vessel, biokinetic parameters of substrate consumption (maximum specific substrate removal rate, qm and half-maximum removal coefficient, Ks) are particularly difficult to measure in biofilm reactors. In this research, a type curve method using load-shift experiments was compared to a method using a least-squared errors (LSE) routine. More accurate and precise estimates were obtained with the LSE routine than with the type curve method by removing subjectivity from the estimation process. In addition, the LSE estimation process allowed a more rigorous evaluation of the adequacy of the data fit, permitted estimation of approximate confidence intervals of parameters, and identified flaws in the data set. As a result, we advocate the use of the recently developed LSE based estimation routine to estimate parameters from such experiments.
On the meaning of the impingement parameter in kinetic equations of diffusion controlled reactions
Starink, M.J.
2001-01-01
If certain preconditions are met, the Johnson-Mehl-Avrami-Kolmogorov (JMAK) kinetic equation is exactly accurate for nucleation and growth reactions with linear growth and is, at least, a good approximation for nucleation and growth reactions with parabolic growth. These preconditions include randomly distributed product phases, isotropic growth and constant equilibrium state. Mechanisms causing deviations from these preconditions include: capillarity effect, vacancy annihilation, blocking du...
Directory of Open Access Journals (Sweden)
I. V. Novash
2015-01-01
Full Text Available This article describes the parameters calculation for the three-phase two-winding power transformer model taken from the SimPowerSystems library, which is the part of the MatLab- Simulink environment. Presented methodology is based on the power transformer nameplate data usage. Particular attention is paid to the power transformer magnetization curve para- meters calculation. The methodology of the three-phase two-winding power transformer model parameters calculation considering the magnetization curve nonlinearity isn’t presented in Russian-and English-language sources. Power transformers demo models described in the SimPowerSystems user’s guide have already calculated parameters, but without reference to the sources of their determination. A power transformer is a nonlinear element of the power system, that’s why for its performance analysis in different modes of operation is necessary to have the magnetization curve parameters.The process analysis during no-load energizing of the power transformer is of special interest. This regime is accompanied by the inrush current on the supply side of the power transformer, which is several times larger than the transformer rated current. Sharp rising of the magnetizing current is explained by the magnetic core saturation. Therefore, magnetiza- tion characteristic accounting during transformer no-load energizing modeling is a mandatory requirement. Article authors attempt to put all calculating formulas in a more convenient form and validate the power transformer nonlinear magnetization characteristics parameters calcu- lation. Inrush current oscillograms obtained during the simulation experiment confirmed the adequacy of the calculated model parameters.
Petillion, Saskia; Swinnen, Ans; Defraene, Gilles; Verhoeven, Karolien; Weltens, Caroline; Van den Heuvel, Frank
2014-07-08
The comparison of the pencil beam dose calculation algorithm with modified Batho heterogeneity correction (PBC-MB) and the analytical anisotropic algorithm (AAA) and the mutual comparison of advanced dose calculation algorithms used in breast radiotherapy have focused on the differences between the physical dose distributions. Studies on the radiobiological impact of the algorithm (both on the tumor control and the moderate breast fibrosis prediction) are lacking. We, therefore, investigated the radiobiological impact of the dose calculation algorithm in whole breast radiotherapy. The clinical dose distributions of 30 breast cancer patients, calculated with PBC-MB, were recalculated with fixed monitor units using more advanced algorithms: AAA and Acuros XB. For the latter, both dose reporting modes were used (i.e., dose-to-medium and dose-to-water). Next, the tumor control probability (TCP) and the normal tissue complication probability (NTCP) of each dose distribution were calculated with the Poisson model and with the relative seriality model, respectively. The endpoint for the NTCP calculation was moderate breast fibrosis five years post treatment. The differences were checked for significance with the paired t-test. The more advanced algorithms predicted a significantly lower TCP and NTCP of moderate breast fibrosis then found during the corresponding clinical follow-up study based on PBC calculations. The differences varied between 1% and 2.1% for the TCP and between 2.9% and 5.5% for the NTCP of moderate breast fibrosis. The significant differences were eliminated by determination of algorithm-specific model parameters using least square fitting. Application of the new parameters on a second group of 30 breast cancer patients proved their appropriateness. In this study, we assessed the impact of the dose calculation algorithms used in whole breast radiotherapy on the parameters of the radiobiological models. The radiobiological impact was eliminated by
Kaplun, V. A.; Kulish, V. G.
1985-05-01
An equivalent circuit is proposed for calculating the characteristics of a dielectric layer with a grid of absorbing semiconductor filaments (used in radar and microwave-antenna technology) in the case of electromagnetic-wave incidence. Mathematical relationships are obtained for circuit parameters for thin and relatively 'thick' filaments with and without allowance for the effect of the air-dielectric interface. Calculation results are compared with experimental data.
Directory of Open Access Journals (Sweden)
Tel Eyyup
2017-01-01
Full Text Available In this study, the (n,α nuclear reaction cross section was calculated for 41K target nuclei for neutron and proton density parameters using SKa, SKb, SLy5, and SLy6 Skyrme force. Theoretical cross section for the (n,α nuclear reaction was obtained using a formula constituted by Tel et al. (2008. Results are compared with experimental data from EXFOR. The calculated results from formula was found in a close agreement with experimental data.
Tel, Eyyup; Sahan, Muhittin; Alkanli, Hasancan; Sahan, Halide; Yigit, Mustafa
2017-09-01
In this study, the (n,α) nuclear reaction cross section was calculated for 41K target nuclei for neutron and proton density parameters using SKa, SKb, SLy5, and SLy6 Skyrme force. Theoretical cross section for the (n,α) nuclear reaction was obtained using a formula constituted by Tel et al. (2008). Results are compared with experimental data from EXFOR. The calculated results from formula was found in a close agreement with experimental data.
Validation of HFCS-I on Calculation of High-Frequency Parameters of Helical Slow-Wave Structures
Zhu, Xiaofang; Yang, Zhonghai; Li, Bin; Li, Jianqing; Xu, Li
2010-02-01
To validate HFCS-I, a newly developed design tool for high frequency circuits of microwave tubes, the high-frequency parameters (including dispersion, interaction impedance and attenuation constant) of a typical helical slow-wave structure (SWS) for millimetre wave travelling-wave tube are calculated by HFCS-I and MAFIA. Both the direct calculation method and the Non-Resonant Perturbation (NRP) technique are adopted to get the interaction impedance. The obtained high-frequency parameters from HFCS-I and MAFIA are compared in detail and the consistency has proved the reliability and validity of HFCS-I.
A comparison of region-based and pixel-based CEUS kinetics parameters in the assessment of arthritis
Grisan, E.; Raffeiner, B.; Coran, A.; Rizzo, G.; Ciprian, L.; Stramare, R.
2014-03-01
Inflammatory rheumatic diseases are leading causes of disability and constitute a frequent medical disorder, leading to inability to work, high comorbidity and increased mortality. The gold-standard for diagnosing and differentiating arthritis is based on patient conditions and radiographic findings, as joint erosions or decalcification. However, early signs of arthritis are joint effusion, hypervascularization and synovial hypertrophy. In particular, vascularization has been shown to correlate with arthritis' destructive behavior, more than clinical assessment. Contrast Enhanced Ultrasound (CEUS) examination of the small joints is emerging as a sensitive tool for assessing vascularization and disease activity. The evaluation of perfusion pattern rely on subjective semi-quantitative scales, that are able to capture the macroscopic degree of vascularization, but are unable to detect the subtler differences in kinetics perfusion parameters that might lead to a deeper understanding of disease progression and a better management of patients. Quantitative assessment is mostly performed by means of the Qontrast software package, that requires the user to define a region of interest, whose mean intensity curve is fitted with an exponential function. We show that using a more physiologically motivated perfusion curve, and by estimating the kinetics parameters separately pixel per pixel, the quantitative information gathered is able to differentiate more effectively different perfusion patterns. In particular, we will show that a pixel-based analysis is able to provide significant markers differentiating rheumatoid arthritis from simil-rheumatoid psoriatic arthritis, that have non-significant differences in clinical evaluation (DAS28), serological markers, or region-based parameters.
Directory of Open Access Journals (Sweden)
Marzieh Aghababaie
2014-09-01
Results: Second order model for Xmax, μmax, P and K was significant but product formation parameters were almost constant. The optimum values of temperature and pH for attaining maximum biomass, maximum specific growth rate, and maximum acid production were obtained at 44 °C and 5.7, respectively. Conclusions: The attained empirical mathematical correlations of RSM alongside the kinetic equations could be used to determine growth conditions under predefined temperature and pH in the fermentation process. Keywords: Lactobacillus bulgaricus, Richards model, Response surface methodology, Lactic acid production, Luedeking-Piret model
Model description and kinetic parameter analysis of MTBE biodegradation in a packed bed reactor
DEFF Research Database (Denmark)
Waul, Christopher Kevin; Arvin, Erik; Schmidt, Jens Ejbye
2008-01-01
A dynamic modeling approach was used to estimate in-situ model parameters, which describe the degradation of methyl tert-butyl ether (MTBE) in a laboratory packed bed reactor. The measured dynamic response of MTBE pulses injected at the reactor's inlet was analyzed by least squares and parameter...
Calculation and comparison of circuit breaker parameters in Power World Simulator
Kuljinder Kaur,; Er. Simerpreet Singh
2016-01-01
A circuit breaker has ratings that an engineer uses for their application. These ratings define circuit breaker performance characteristics. A good understanding of Ratings allow the electrical engineer to make a proper comparison of various circuit breaker designs. In this research work, the different ratings of circuit breaker were calculated. The other objective of this work was comparison between ratings of existing circuit breaker and calculated ratings in POWER WORLD SIMU...
Binder, Tobias; Bringmann, Torsten; Gustafsson, Michael; Hryczuk, Andrzej
2017-12-01
Calculating the abundance of thermally produced dark matter particles has become a standard procedure, with sophisticated methods guaranteeing a precision that matches the percent-level accuracy in the observational determination of the dark matter density. Here, we point out that one of the main assumptions in the commonly adopted formalism, namely local thermal equilibrium during the freeze-out of annihilating dark matter particles, does not have to be satisfied in general. We present two methods for how to deal with such situations, in which the kinetic decoupling of dark matter happens so early that it interferes with the chemical decoupling process: (i) an approximate treatment in terms of a coupled system of differential equations for the leading momentum moments of the dark matter distribution, and (ii) a full numerical solution of the Boltzmann equation in phase space. For illustration, we apply these methods to the case of scalar singlet dark matter. We explicitly show that even in this simple model the prediction for the dark matter abundance can be affected by up to 1 order of magnitude compared to the traditional treatment.
Pavlova, Anna; Parks, Jerry M; Gumbart, James C
2018-01-15
Corrinoid cofactors such as cobalamin are used by many enzymes and are essential for most living organisms. Therefore, there is broad interest in investigating cobalamin-protein interactions with molecular dynamics simulations. Previously developed parameters for cobalamins are based mainly on crystal structure data. Here, we report CHARMM-compatible force field parameters for several corrinoids developed from quantum mechanical calculations. We provide parameters for corrinoids in three oxidation states, Co3+, Co2+ and Co1+, and with various axial ligands. Lennard-Jones parameters for the cobalt center in the Co(II) and Co(I) states were optimized using a helium atom probe, and partial atomic charges were obtained with a combination of natural population analysis (NPA) and restrained electrostatic potential (RESP) fitting approaches. The Force Field Toolkit was used to optimize all bonded terms. The resulting parameters, determined solely from calculations of cobalamin alone or in water, were then validated by assessing their agreement with DFT geometries and by analyzing molecular dynamics simulation trajectories of several corrinoid proteins for which X-ray crystal structures are available. In each case, we obtained excellent agreement with the reference data. In comparison to previous CHARMM-compatible parameters for cobalamin we observe a better agreement for the fold angle and lower RMSD in the cobalamin binding site. The approach described here is readily adaptable for developing CHARMM-compatible force-field parameters of other corrinoids or large biomolecules.
Dhyani, Vaibhav; Kumar Awasthi, Mukesh; Wang, Quan; Kumar, Jitendra; Ren, Xiuna; Zhao, Junchao; Chen, Hongyu; Wang, Meijing; Bhaskar, Thallada; Zhang, Zengqiang
2017-12-27
In this work, the influence of composting on the thermal decomposition behavior and decomposition kinetics of pig manure-derived solid wastes was analyzed using thermogravimetry. Wheat straw, biochar, zeolite, and wood vinegar were added to pig manure during composting. The composting was done in the 130 L PVC reactors with 100 L effective volume for 50 days. The activation energy of pyrolysis of samples before and after composting was calculated using Friedman's method, while the pre-exponential factor was calculated using Kissinger's equation. It was observed that composting decreased the volatile content of all the samples. The additives when added together in pig manure lead to a reduction in the activation energy of decomposition, advocating the presence of simpler compounds in the compost material in comparison with the complex feedstock. Copyright © 2017 Elsevier Ltd. All rights reserved.
Zhu, Hongchun; Cai, Lijie; Liu, Haiying; Huang, Wei
2016-01-01
Multi-scale image segmentation and the selection of optimal segmentation parameters are the key processes in the object-oriented information extraction of high-resolution remote sensing images. The accuracy of remote sensing special subject information depends on this extraction. On the basis of WorldView-2 high-resolution data, the optimal segmentation parameters methodof object-oriented image segmentation and high-resolution image information extraction, the following processes were conducted in this study. Firstly, the best combination of the bands and weights was determined for the information extraction of high-resolution remote sensing image. An improved weighted mean-variance method was proposed andused to calculatethe optimal segmentation scale. Thereafter, the best shape factor parameter and compact factor parameters were computed with the use of the control variables and the combination of the heterogeneity and homogeneity indexes. Different types of image segmentation parameters were obtained according to the surface features. The high-resolution remote sensing images were multi-scale segmented with the optimal segmentation parameters. Ahierarchical network structure was established by setting the information extraction rules to achieve object-oriented information extraction. This study presents an effective and practical method that can explain expert input judgment by reproducible quantitative measurements. Furthermore the results of this procedure may be incorporated into a classification scheme.
Cai, L; Cao, A; Lai, L
2001-12-01
An isothermal titration calorimetric (ITC) method was developed to measure the kinetic parameters of ribonuclease A catalytic hydrolysis of cytidine 2',3'-cyclic monophosphate. Employing the inhibition of product as a probe, the K(m), K(i), k(c), and DeltaH(m) can be determined by two simple calorimetric measurements. First, the substrate was titrated into the cell containing high concentration of enzyme. The molar reaction heat was calculated from the titration peak area divided by substrate moles per titration, and the initial catalytic reaction rate in the presence of various concentrations of product can be calculated from the peak height and the molar reaction heat. From Michaelis-Menten function in the presence of inhibitors, the relationship between K(m) and K(i) can be obtained. Then, the dissociation constant, which is equal to K(i), was measured by a regular ITC experiment. Thus, K(m) and k(c) can be calculated. The method developed here can be applied in other enzyme catalytic systems with inhibitive products.
Furmaniak, Sylwester; Terzyk, Artur P; Gauden, Piotr A; Harris, Peter J F; Kowalczyk, Piotr
2010-01-29
We present the results of a systematic study of the influence of carbon surface oxidation on Dubinin-Astakhov isotherm parameters obtained from the fitting of CO2 adsorption data. Using GCMC simulations of adsorption on realistic VPC models differing in porosity and containing the most frequently occurring carbon surface functionalities (carboxyls, hydroxyls and carbonyls) and their mixtures, it is concluded that the maximum adsorption calculated from the DA model is not strongly affected by the presence of oxygen groups. Unfortunately, the same cannot be said of the remaining two parameters of this model i.e. the heterogeneity parameter (n) and the characteristic energy of adsorption (E0). Since from the latter the pore diameters of carbons are usually calculated, by inverse-type relationships, it is concluded that they are questionable for carbons containing surface oxides, especially carboxyls.
AMORPHOUS SILICON ELECTRONIC STRUCTURE MODELING AND BASIC ELECTRO-PHYSICAL PARAMETERS CALCULATION
Directory of Open Access Journals (Sweden)
B. A. Golodenko
2014-01-01
Full Text Available Summary. The amorphous semiconductor has any unique processing characteristics and it is perspective material for electronic engineering. However, we have not authentic information about they atomic structure and it is essential knot for execution calculation they electronic states and electro physical properties. The author's methods give to us decision such problem. This method allowed to calculation the amorphous silicon modeling cluster atomics Cartesian coordinates, determined spectrum and density its electronic states and calculation the basics electro physical properties of the modeling cluster. At that determined numerical means of the energy gap, energy Fermi, electron concentration inside valence and conduction band for modeling cluster. The find results provides real ability for purposeful control to type and amorphous semiconductor charge carriers concentration and else provides relation between atomic construction and other amorphous substance physical properties, for example, heat capacity, magnetic susceptibility and other thermodynamic sizes.
Directory of Open Access Journals (Sweden)
Sornek Krzysztof
2016-01-01
Full Text Available The proper design of renewable energy based systems is really important to provide their efficient and safe operation. The aim of this paper is to compare the results obtained during traditional static calculations, with the results of dynamic simulations. For this reason, simulations of solar water heating (SWH system, designed for a typical residential building, were conducted in the TRNSYS (Transient System Simulation Tool. Carried out calculations allowed to determine the heat generation in the discussed system as well as to estimate the efficiency of considered installation. Obtained results were compared with the results from other available tool based on the static calculations. It may be concluded, that using dynamic simulations at the designing stage of renewable energy based systems may help to avoid many exploitation problems (including low efficiency, overheating etc. and allows to provide safe exploitation of such installations.
Dračínský, Martin; Bouř, Petr; Hodgkinson, Paul
2016-03-08
The influence of temperature on NMR chemical shifts and quadrupolar couplings in model molecular organic solids is explored using path integral molecular dynamics (PIMD) and density functional theory (DFT) calculations of shielding and electric field gradient (EFG) tensors. An approach based on convoluting calculated shielding or EFG tensor components with probability distributions of selected bond distances and valence angles obtained from DFT-PIMD simulations at several temperatures is used to calculate the temperature effects. The probability distributions obtained from the quantum PIMD simulations, which includes nuclear quantum effects, are significantly broader and less temperature dependent than those obtained with conventional DFT molecular dynamics or with 1D scans through the potential energy surface. Predicted NMR observables for the model systems were in excellent agreement with experimental data.
Directory of Open Access Journals (Sweden)
Imane EL Ouahabi
2015-11-01
Full Text Available The aim of this study is to valorise the mussel shells and evaluate the adsorption capacity of calcined mussel shells for the cationic dyes. The adsorbent was characterized by DRX, FTIR, BET and SEM, respectively. The adsorption of Yellow Basic28 on calcined mussel shells was investigated using the parameters such as concentrations (10-50mg/L, pH (3-10, ionic strength (0-2 mol / L and temperature (288 - 318 °C. The adsorption rate data were analysed according to the ﬁrst and second-order kinetic models. The adsorption kinetics was found to be best represented by the pseudo-second-order kinetic model. The experimental isotherm data were analyzed using Langmuir, Freundlich, Temkin, Elovich and Dubinin–Radushkevich isotherm equations on the dye-adsorbent system. The experimental data yielded excellent ﬁts with Freundlich isotherm equation (R² = 0.966. It was indicative of the heterogeneity of the adsorption sites on the CMS particles. Various thermodynamic parameters such as enthalpy of adsorption ΔH°, free energy change ΔG°and entropy ΔS° were estimated. The positive value of ΔH°(30.321 kJ/mol and negative values of ΔG° (from -5.392 to -2.873 kJ/mol show the process is endothermic and spontaneous. The negative value of entropy ΔS° (-87.172 J/mol K suggest the decreased randomness at the solid-liquid interface during the adsorption of dyes onto calcined mussel shells.
Behnajady, Mohammad A; Mansoriieh, Nafiseh; Modirshahla, Nasser; Shokri, Mohammad
2012-01-01
In the present work the performance of immobilized ZnO on a glass plate with the heat attachment method has been described for photoreduction of Cr(VI) to the less harmful Cr(III) at different operational parameters. The photoreduction of Cr(VI) on the surface of the immobilized ZnO catalyst was studied as a function of the pH of solution, initial Cr(VI) concentration and ultraviolet (UV) light intensity. Results indicated that the reduction rate decreases with increasing initial concentration of Cr(VI) and initial pH of solution, whereas it increases with increasing UV light intensity. The photoreduction rate of Cr(VI) on the surface of the immobilized ZnO in the presence of O2 as mobile gas is more than Ar and N2. The reduction process of Cr(VI) by immobilized ZnO also could be done under visible light irradiation. Pseudo first-order kinetics were observed for the photoreduction of Cr(VI) at different operational conditions. With non-linear regression analysis a mathematical kinetics model was developed for the pseudo first-order constant (k(ap)) as a function of operational parameters.
Ostrovskiĭ KuM; Voskoboev, A I; Gorenshtenĭn, B I; Dosta, G A
1979-09-01
The molecula-kinetic parameters (Km, Ki) of three thiamine enzymes, e. g. thiamine pyrophosphokinase (EC 2.7.6.2), pyruvate dehydrogenase (EC 1.2.4.1) and transketolase (EC 2.2.1.1) with respect to the effects of the thiamine antimetabolite hydroxythiamine in the whole animal organism have been compared. It has been shown that only the first two enzymes, which interact competitively with the vitamin, antivitamin or their pyrophosphate ethers, obey the kinetic parameters obtained for the purified enzymes in vitro. The anticoenzymic effect of hydroxythiamine pyrophosphate with respect to transketolase is not observed in vivo at maximal concentration of the anticoenzyme in tissues due to the absence of competitive interactions with thiamine pyrophosphate. The incorporation of the true and false coenzymes into transketolase occurs only during de novo transketolase synthesis (the apoform is absent in tissues, with the exception of erythrocytes) and proceeds slowly with a half-life time equal to 24--30 hrs. After a single injection of hydroxythiamine at a large dose (70--400 mg/kg) the maximal inhibition of the transketolase activity in tissues (liver, heart, kidney, muscle, spleen, lungs adrenal grands) manifests itself by the 48th--72nd hour, when the concentration of free hydroxythiamine and its pyrophosphate is minimal and the whole anticoenzyme is tightly bound to the protein, forming the false holoenzyme. The use of hydroxythiamine for inhibition of pyruvate dehydrogenase or transketolase in animal organism is discussed.
Energy Technology Data Exchange (ETDEWEB)
Huang, J.-W. [Department of Styling and Cosmetology, Tainan University of Technology, 529 Chung Cheng Road, Yung Kang City 710, Taiwan (China)], E-mail: jw.huang@msa.hinet.net; Chang, C.-C. [Department of International Business Management, Tainan University of Technology, 529 Chung Cheng Road, Yung Kang City 710, Taiwan (China); Kang, C.-C. [R and D Center, Hi-End Polymer Film Co., Ltd., 15-1 Sin Jhong Road, Sin Ying City 730, Taiwan (China); Yeh, M.-Y. [Department of Chemistry, National Cheng Kung University, No. 1, University Road, Tainan City 701, Taiwan (China); Sustainable Environment Research Centre, National Cheng Kung University, Taiwan (China)
2008-02-05
Blend of Nylon 6 and poly(ethylene-co-glycidyl methacrylate) (PEGMA) were prepared by a twin-screw extruder. Morphology observed with scanning electron microscopies (SEM) show PEGMA is well dispersed in Nylon 6 matrix. Isothermal and nonisothermal crystallization of the blend was investigated by differential scanning calorimeter (DSC) and crystallization kinetics was described by Avrami and Tobin models. Equilibrium melting temperatures were estimated from linear Hoffman-Weeks relationship. All analyses showed that the reaction between PEGMA and Nylon 6 reduced the molecular mobility and reduced the crystallization rate. Expand K{sub g} and U* in the Hoffman-Lauritzen equation by Vyazovkin's method demonstrated that Nylon 6/PEGMA had higher K{sub g} and U* values and provided another supportive evidence to the above interpretation.
Parameter-free calculation of K alpha chemical shifts for Al, Si, and Ge oxides
DEFF Research Database (Denmark)
Lægsgaard, Jesper
2001-01-01
The chemical shifts of the K alpha radiation line from Al, Si, and Ge ions between their elemental and oxide forms are calculated within the framework of density functional theory using ultrasoft pseudopotentials. It is demonstrated that this theoretical approach yields quantitatively accurate...
Calculation of the Weizsacker mass-formula parameters on the basis of the consistency conditions
Energy Technology Data Exchange (ETDEWEB)
Sapershtein, E.E.; Khodel' , V.E.
1977-02-20
The consistency conditions imposed by spontaneous violation of translational invariance on the quasiparticle density rho, on the local quasiparticle amplitude F, and on the self-consistent potential U of the nucleus are used to calculate the coefficients of the Weizsacker formula and other characteristics of nuclear matter.
Energy Technology Data Exchange (ETDEWEB)
Geslot, Benoit; Pepino, Alexandra; Blaise, Patrick; Mellier, Frederic [CEA, DEN, DER/SPEx, Cadarache, F-13108 St Paul Lez Durance (France); Lecouey, Jean-Luc [LPC Caen, ENSICAEN, Universite de Caen, CNRS/IN2P3, 6 Bd. Marechal Juin 14050 Caen cedex (France); Carta, Mario [ENEA, UTFISST-REANUC, C.R. Casaccia, S.P.040 via Anguillarese 301, 00123 S. Maria Di Galeria, Roma (Italy); Kochetkov, Anatoly; Vittiglio, Guido [SCK.CEN, Belgian Nuclear Research Centre, Boeretang 200, BE-2400, Mol (Belgium); Billebaud, Annick [LPSC, CNRS, IN2P3/UJF/INPG, 53 Avenue des Martyrs, 38026 Grenoble cedex (France)
2015-07-01
A pile noise measurement campaign has been conducted by the CEA in the VENUS-F reactor (SCK-CEN, Mol Belgium) in April 2011 in the reference critical configuration of the GUINEVERE experimental program. The experimental setup made it possible to estimate the core kinetic parameters: the prompt neutron decay constant, the delayed neutron fraction and the generation time. A precise assessment of these constants is of prime importance. In particular, the effective delayed neutron fraction is used to normalize and compare calculated reactivities of different subcritical configurations, obtained by modifying either the core layout or the control rods position, with experimental ones deduced from the analysis of measurements. This paper presents results obtained with a CEA-developed time stamping acquisition system. Data were analyzed using Rossi-α and Feynman-α methods. Results were normalized to reactor power using a calibrated fission chamber with a deposit of Np-237. Calculated factors were necessary to the analysis: the Diven factor was computed by the ENEA (Italy) and the power calibration factor by the CNRS/IN2P3/LPC Caen. Results deduced with both methods are consistent with respect to calculated quantities. Recommended values are given by the Rossi-α estimator, that was found to be the most robust. The neutron generation time was found equal to 0.438 ± 0.009 μs and the effective delayed neutron fraction is 765 ± 8 pcm. Discrepancies with the calculated value (722 pcm, calculation from ENEA) are satisfactory: -5.6% for the Rossi-α estimate and -2.7% for the Feynman-α estimate. (authors)
Yadav, Jayprakash; Rafique, S. M.; Kumari, Shanti
2009-10-01
In the present paper some superconducting (SC) state parameters of metals Ga, Cd and In have been studied through Harrison's First Principle [HFP] pseudopotential technique using McMillan's formalism. The impact of choosing two different sets of core energy eigenvalues viz. Herman-Skillman and Clementi (or Experimental) has been studied.
Winter, Samantha Lee; Forrest, Sarah Michelle; Wallace, Joanne; Challis, John H
2017-08-08
The purpose of this study was to validate a new geometric solids model, developed to address the lack of female specific models for body segment inertial parameter estimation. A second aim was to determine the effect of reducing the number of geometric solids used to model the limb segments on model accuracy. The 'full' model comprised 56 geometric solids, the 'reduced' 31, and the 'basic' 16. Predicted whole-body inertial parameters were compared with direct measurements (reaction board, scales), and predicted segmental parameters with those estimated from whole-body DXA scans for 28 females. The percentage root mean square error (%RMSE) for whole-body volume was <2.5% for all models, and 1.9% for the full model. The %RMSE for whole-body center of mass location was <3.2% for all models. The %RMSE whole-body mass was <3.3% for the full model. The RMSE for segment masses was <0.5 kg (<0.5%) for all segments; Bland-Altman analysis showed the full and reduced models could adequately model thigh, forearm, foot and hand segments, but the full model was required for the trunk segment. The proposed model was able to accurately predict body segment inertial parameters for females, more geometric solids are required to more accurately model the trunk.
Tepper, H.L.; Scheinhardt-Engels, S.M.; Briels, Willem J.
2003-01-01
A method is presented to design order parameters that can be used as discriminator in two-phase crystal-liquid molecular dynamics simulations. The proposed methodology is an extension to molecular crystal structures of a previously introduced discriminator for the atomic fcc environment [Phys. Rev.
Walsh, Mark S; Waters, Jeff; Kersting, Uwe G
2007-01-01
The purposes of this study were to examine gender differences during drop jumps, to evaluate the effect of a set of simple instructions on kinematic and kinetic parameters during a drop jump, and to determine if there are gender differences in the effects of instruction on those parameters. Twenty-five basketball players, 13 men and 12 women, performed drop jumps from a box (height 30.5 cm) after being asked to perform a land and jump movement as they normally would do when aiming at maximum jump height. The experimental group received a set of instructions designed to make them land softer. The measured parameters were impact force at landing, ground contact time, flight time, frontal plane knee angle, sagittal plane knee angle, and distance between the knees. When the groups were examined by gender, no differences in the parameters were seen in men after instruction, but in women the following significant differences were detected: an increase in contact time, a decrease in landing force, and a decrease in inward movement of the knees after landing. These data indicate that females respond differently to jumping/landing instructions.
National Research Council Canada - National Science Library
Zaanoun, I; Gharby, S; Bakass, I; Ait addi, E; Ait ichou, I
2014-01-01
...) under the Rancimat test conditions. The physicochemical parameters of edible and cosmetic argan oil immediately after preparation and after accelerated oxidation test Rancimat at different temperatures 90 °C, 100 °C, 110 °C, 120 °C, 130 °C and 140...
Sensitivity analysis of large system of chemical kinetic parameters for engine combustion simulation
Energy Technology Data Exchange (ETDEWEB)
Hsieh, H; Sanz-Argent, J; Petitpas, G; Havstad, M; Flowers, D
2012-04-19
In this study, the authors applied the state-of-the art sensitivity methods to downselect system parameters from 4000+ to 8, (23000+ -> 4000+ -> 84 -> 8). This analysis procedure paves the way for future works: (1) calibrate the system response using existed experimental observations, and (2) predict future experiment results, using the calibrated system.
Calculation of PID controller parameters by using a fuzzy neural network.
Lee, Ching-Hung; Teng, Ching-Cheng
2003-07-01
In this paper, we use the fuzzy neural network (FNN) to develop a formula for designing the proportional-integral-derivative (PID) controller. This PID controller satisfies the criteria of minimum integrated absolute error (IAE) and maximum of sensitivity (Ms). The FNN system is used to identify the relationship between plant model and controller parameters based on IAE and Ms. To derive the tuning rule, the dominant pole assignment method is applied to simplify our optimization processes. Therefore, the FNN system is used to automatically tune the PID controller for different system parameters so that neither theoretical methods nor numerical methods need be used. Moreover, the FNN-based formula can modify the controller to meet our specification when the system model changes. A simulation result for applying to the motor position control problem is given to demonstrate the effectiveness of our approach.
Llovet, X.; Salvat, F.
2018-01-01
The accuracy of Monte Carlo simulations of EPMA measurements is primarily determined by that of the adopted interaction models and atomic relaxation data. The code PENEPMA implements the most reliable general models available, and it is known to provide a realistic description of electron transport and X-ray emission. Nonetheless, efficiency (i.e., the simulation speed) of the code is determined by a number of simulation parameters that define the details of the electron tracking algorithm, which may also have an effect on the accuracy of the results. In addition, to reduce the computer time needed to obtain X-ray spectra with a given statistical accuracy, PENEPMA allows the use of several variance-reduction techniques, defined by a set of specific parameters. In this communication we analyse and discuss the effect of using different values of the simulation and variance-reduction parameters on the speed and accuracy of EPMA simulations. We also discuss the effectiveness of using multi-core computers along with a simple practical strategy implemented in PENEPMA.
Sukhovoj, A M; Khitrov, V A
2001-01-01
The level density and radiative strength functions which accurately reproduce the experimental intensity of two- step cascades after thermal neutron capture and the total radiative widths of the compound states were applied to calculate the total gamma-ray spectra from the (n,gamma) reaction. In some cases, analysis showed far better agreement with experiment and gave insight into possible ways in which these parameters need to be corrected for further improvement of calculation accuracy for the cascade gamma-decay of heavy nuclei.
Krapf, Sebastian; Koslowski, Thorsten; Steinbrecher, Thomas
2010-08-28
DNA Photolyases are light sensitive oxidoreductases present in many organisms that participate in the repair of photodamaged DNA. They are capable of electron transfer between a bound cofactor and a chain of tryptophan amino acid residues. Due to their unique mechanism and important function, photolyases have been subject to intense study in recent times, with both experimental and computational efforts. In this work, we present a novel application of classical molecular dynamics based free energy calculations, combined with quantum mechanical computations, to biomolecular charge transfer. Our approach allows for the determination of all reaction parameters in Marcus' theory of charge transport. We were able to calculate the free energy profile for the movement of a positive charge along protein sidechains involved in the biomolecule's function as well as charge-transfer rates that are in good agreement with experimental results. Our approach to simulate charge-transfer reactions explicitly includes the influence of protein flexibility and solvent dynamics on charge-transfer energetics. As applied here to a biomolecular system of considerable scientific interest, we believe the method to be easily adaptable to the study of charge-transfer phenomena in biochemistry and other fields.
Energy Technology Data Exchange (ETDEWEB)
Butcher, B.M.
1997-08-01
A summary of the input parameter values used in final predictions of closure and waste densification in the Waste Isolation Pilot Plant disposal room is presented, along with supporting references. These predictions are referred to as the final porosity surface data and will be used for WIPP performance calculations supporting the Compliance Certification Application to be submitted to the U.S. Environmental Protection Agency. The report includes tables and list all of the input parameter values, references citing their source, and in some cases references to more complete descriptions of considerations leading to the selection of values.
Abdul Jameel, Abdul Gani
2016-04-22
Heavy fuel oil (HFO) is primarily used as fuel in marine engines and in boilers to generate electricity. Nuclear Magnetic Resonance (NMR) is a powerful analytical tool for structure elucidation and in this study, 1H NMR and 13C NMR spectroscopy were used for the structural characterization of 2 HFO samples. The NMR data was combined with elemental analysis and average molecular weight to quantify average molecular parameters (AMPs), such as the number of paraffinic carbons, naphthenic carbons, aromatic hydrogens, olefinic hydrogens, etc. in the HFO samples. Recent formulae published in the literature were used for calculating various derived AMPs like aromaticity factor 〖(f〗_a), C/H ratio, average paraffinic chain length (¯n), naphthenic ring number 〖(R〗_N), aromatic ring number〖 (R〗_A), total ring number〖 (R〗_T), aromatic condensation index (φ) and aromatic condensation degree (Ω). These derived AMPs help in understanding the overall structure of the fuel. A total of 19 functional groups were defined to represent the HFO samples, and their respective concentrations were calculated by formulating balance equations that equate the concentration of the functional groups with the concentration of the AMPs. Heteroatoms like sulfur, nitrogen, and oxygen were also included in the functional groups. Surrogate molecules were finally constructed to represent the average structure of the molecules present in the HFO samples. This surrogate molecule can be used for property estimation of the HFO samples and also serve as a surrogate to represent the molecular structure for use in kinetic studies.
Relativistic calculations of screening parameters and atomic radii of neutral atoms
Guerra, M.; Amaro, P.; Santos, J. P.; Indelicato, P.
2017-09-01
Calculations of the effective nuclear charge for elements with 1 ≤ Z ≤ 118 have been performed in a Dirac-Fock approach including all relativistic effects as well as contributions from quantum electrodynamics. Maximum charge density for every subshell of every element in the periodic table was also computed in the same framework as well as atomic radii based on the total charge density. Results were compared with the extensively cited works of Clementi et al., obtained in the 1960s with Roothan's self-consistent-field method.
Expectation Value Calculation of Grid QoS Parameters Based on Algorithm Prim
Kaijian Liang; Linfeng Bai; Xilong Qu
2011-01-01
From the perspective of selecting service by QoS attributes, a computation method of QoS expectation value, which is based on Algorithm Prim, was presented to provide support for selection of service. On the basis of the ability of service providers, by Algorithm Prim, this method succeded in calculating a set of balanced expectation values of QoS. Selection of service based on these QoS values would be beneficial to optimization of system resources and protection of the users of those servic...
Patra, Braja N; Majhi, Deola
2015-06-25
Polyaniline was synthesized by the oxidative polymerization method by using ammonium persulfate as an oxidant. The positive charge in the backbone of the polymer was generated by using Potash alum as a dopant. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X-ray fluorescence (XRF), and X-ray diffraction (XRD) techniques were used for characterization of doped polyaniline. The doped polyaniline can be used for selective adsorption of various dyes (selectively sulfonated dyes) from aqueous solution. Adsorption studies regarding the effect of contact time, initial dye concentration, pH, doses of adsorbent, and temperature on adsorption kinetics were investigated. The influence of other anions like Cl(-), NO3(-), and SO4(2-) on the adsorption density of dyes onto doped polyaniline was also explored. Langmuir isotherm and pseudo-second-order kinetics were found to be the most appropriate models to describe the removal of anionic dyes from water through adsorption. Thermodynamic parameters such as free energy (ΔG(0)), enthalpy (ΔH(0)), and entropy (ΔS(0)) changes were also evaluated. The interaction of dyes with doped polyaniline was also investigated by FTIR and UV spectroscopy.
Sharifian, Mohammad Hossain; Mahdavian, Ali Reza; Salehi-Mobarakeh, Hamid
2017-08-15
Chemical bonding between photochromic compounds and polymer matrices will induce several consitions such as photostability, photoreversibility, elimination of dye aggregation, and undesirable negative photochromism. In such polymeric systems, the switching rate and photoisomerization are closely dependent on several parameters like chain flexibility, steric restrictions, polarity, and even proticity of the surrounding medium. Here, copolymerization of a synthesized spiropyran-based monomer with butyl acrylate (BA) and methyl methacrylate (MMA) comonomers was carried out with various compositions of MMA and BA through emulsion polymerization, and the corresponding photoisomerization kinetics were studied. Particle sizes and their distributions were analyzed by dynamic light scattering, and morphologies were investigated by scanning and transmission electron microscopic analyses. The results showed the particles are spherical with diameter 62-82 nm. Differential scanning calorimetric thermograms were employed to determine Tg of the prepared copolymers, which ranged from -23 to 93 °C. The kinetics of photoisomerization was then studied by UV-vis spectroscopy. Finally, a latex containing spiropyran/acrylic copolymer with Tg of about 0 °C and optimum rate of coloration and decoloration was considered in reversible optical data storage studies due to its fast photochromism and good film-formation properties.
Parameter estimation for VLE calculation by global minimization: the genetic algorithm
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V. H. Alvarez
2008-06-01
Full Text Available Vapor-liquid equilibrium calculations require global minimization of deviations in pressure and gas phase compositions. In this work, two versions of a stochastic global optimization technique, the genetic algorithm, the freeware MyGA program, and the modified mMyGA program, are evaluated and compared for vapor-liquid equilibrium problems. Reliable experimental data from the literature on vapor liquid equilibrium for water + formic acid, tert-butanol + 1-butanol and water + 1,2-ethanediol systems were correlated using the Wilson equation for activity coefficients, considering acid association in both liquid and vapor phases. The results show that the modified mMyGA is generally more accurate and reliable than the original MyGA. Next, the mMyGA program is applied to the CO2 + ethanol and CO2 + 1-n-butyl-3-methylimidazolium hexafluorophosphate systems, and the results show a good fit for the data.
Parameter-free calculation of charge-changing cross sections at high energy
Suzuki, Y.; Horiuchi, W.; Terashima, S.; Kanungo, R.; Ameil, F.; Atkinson, J.; Ayyad, Y.; Cortina-Gil, D.; Dillmann, I.; Estradé, A.; Evdokimov, A.; Farinon, F.; Geissel, H.; Guastalla, G.; Janik, R.; Knoebel, R.; Kurcewicz, J.; Litvinov, Yu. A.; Marta, M.; Mostazo, M.; Mukha, I.; Nociforo, C.; Ong, H. J.; Pietri, S.; Prochazka, A.; Scheidenberger, C.; Sitar, B.; Strmen, P.; Takechi, M.; Tanaka, J.; Tanihata, I.; Vargas, J.; Weick, H.; Winfield, J. S.
2016-07-01
Charge-changing cross sections at high energies are expected to provide useful information on nuclear charge radii. No reliable theory to calculate the cross section has yet been available. We develop a formula using Glauber and eikonal approximations and test its validity with recent new data on carbon isotopes measured at around 900 A MeV. We first confirm that our theory reproduces the cross sections of 12,13,14C+12C consistently with the known charge radii. Next we show that the cross sections of C-1912 on a proton target are all well reproduced provided the role of neutrons is accounted for. We also discuss the energy dependence of the charge-changing cross sections.
Feedback of the new RPI Gd resonance parameters seton FUBILA Full MOX poisoned core calculation
Energy Technology Data Exchange (ETDEWEB)
Blaise, P.; Litaize, O. [CEA Cadarache, DEN/DER/SPRC/LEPh, 13 - Saint-Paul-lez-Durance (France)
2009-07-01
Recently, gadolinium cross sections were measured at the Rensselaer Polytechnic Institute (RPI) by Leinweber et al. and differed significantly from current library values. Jeff3.1.1 gadolinium cross sections have currently been modified to include the new measurements, and these data have been processed with NJOY/CALENDF to yield files usable by TRIPOLI4 Monte Carlo code. Fission rates in the gadolinium-poisoned fuel pins of the FUBILA/UGD core pins were increased by 1.4 to 2.0% using the newly produced cross sections, yielding to a better agreement with the experimental values. Earlier reported discrepancies observed in the EOLE integral experiments, between measured and calculated reaction rates in the gadolinium-poisoned pins, might thus be due to inaccurate gadolinium cross sections. (authors)
Calculation of gamma-ray attenuation parameters for locally developed shielding material: Polyboron
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Ripan Biswas
2016-01-01
Full Text Available In the present study, the mass attenuation coefficient (μm has been calculated analytically for a locally developed shielding material, polyboron, and compared with the values obtained from the WinXCom code, a Windows version of the XCOM database at the photon energy range 0.001 MeV–20 MeV. A good agreement has been observed between these two values. The linear attenuation coefficients (μ and relaxation lengths (λ have also been calculated from the obtained μm values and their variations with photon energy have been plotted. For comparison, other four shielding materials- ordinary concrete, pure polyethylene, borated polyethylene and water have also been studied. The obtained result shows that μm, μ and λ strongly depends on the photon energy, chemical composition and density of the shielding materials. The values of μm and μ of polyboron have been found greater than those of pure polyethylene and borated polyethylene but less than those of ordinary concrete and water at low photon energy range; and at the intermediate photon energy range (0.125 MeV–6 MeV, all the sample materials have approximately the same μm values. It has also been noticed that polyboron has the medial relaxation length (λ over the entire photon energy range. The total mass attenuation coefficient (μm and linear attenuation coefficient (μ, Half Value Layer (HVL and Tenth Value Layer (TVL of the five sample materials for some common gamma sources have been worked out and the transmission curves have been plotted. The curves exhibit that the transmission factor of the sample materials decreases with the increase in shielding thickness. The results of this study can be utilized to comprehend the shielding effectiveness of this locally developed material.
Influence of kinetic effects on a sheath potential and divertor plasma parameters in ITER
Energy Technology Data Exchange (ETDEWEB)
Krasheninnikov, S.I.; Soboleva, T.K.; Igitkhanov, Yu.L.; Runov, A.M. (Kurchatov Institute, Moscow (Russian Federation))
1991-01-01
It was already noted that strong inhomogeneity of ITER divertor plasma parameters may be a reason of a pronounced deviation of a sheath potential U[sub d] at a plasma-divertor plate contact from the local value U[sub d][approx]3.5T[sub d] (T[sub d] is an electron temperature in a vicinity of the divertor plate). This effect may badly influence the divertor plates sputtering resulting in a plasma contamination. (author) 6 refs., 5 figs.
Cirelli, Giuseppe Luigi; Consoli, Simona; Juanicó, Marcelo
2009-01-01
The operational parameter MRT%FE, representing the mean residence time of different ages fractions of effluent within a completely mixed reactor, was evaluated and integrated with first order kinetics. The parameter was used to model Escherichia coli concentrations in a municipal wastewater reservoir managed under different operating conditions (continuous and discontinuous). The study was conducted during 2004-2005 in a reservoir receiving effluents from the activated sludge treatment plant of Caltagirone (Eastern Sicily - Italy). The analytical approach is applied to the hydraulic state variables of the system (daily stored volumes, inlet and outlet flows), and the physical-chemical (pH, temperature, EC, TSS, BOD(5), COD) and bacteriological wastewater parameters (E. coli, FC, FS). In order to evaluate the reliability of the proposed approach, predicted E. coli concentrations within the reservoir were compared with measured ones by the correlation coefficient, F-test and Sperman's index. The study included the evaluation of die-off coefficient K(T) (d(-1)), light extinction coefficient K (m(-1)) and their relationships with climatic factors. Results of the study confirm that E. coli removal is related to the fractions of fresh effluent remaining each day within the reservoir with MRT%FE of about 5-8d, significantly lower than the nominal detention time (about 27d). The E. coli die-off coefficient (K(T)) was higher during system discontinuous operations and correlated with incident solar radiation and water temperature.
Hashim, S; Alajerami, Y S M; Ramli, A T; Ghoshal, S K; Saleh, M A; Abdul Kadir, A B; Saripan, M I; Alzimami, K; Bradley, D A; Mhareb, M H A
2014-09-01
Lithium potassium borate (LKB) glasses co-doped with TiO2 and MgO were prepared using the melt quenching technique. The glasses were cut into transparent chips and exposed to gamma rays of (60)Co to study their thermoluminescence (TL) properties. The TL glow curve of the Ti-doped material featured a single prominent peak at 230 °C. Additional incorporation of MgO as a co-activator enhanced the TL intensity threefold. LKB:Ti,Mg is a low-Z material (Z(eff)=8.89) with slow signal fading. Its radiation sensitivity is 12 times lower that the sensitivity of TLD-100. The dose response is linear at doses up to 10(3) Gy. The trap parameters, such as the kinetics order, activation energy, and frequency factor, which are related to the glow peak, were determined using TolAnal software. Copyright © 2014 Elsevier Ltd. All rights reserved.
Kundin, Julia
2017-06-01
The present paper proposes an extension to the phase-field model of Kobayashi, Warren and Carter (KWC) as described in (Warren et al 2002 Acta Mater.) to incorporate the recrystallization process which occurs during heat treatments of alloy systems with predeformed defect structure. The standard KWC model is extended by an additional order parameter for recrystallized grains and describes the general results for the steady-state moving boundary. The simulation results of the initial grain growth and recrystallization process in various systems show that the extended phase-field model is able to describe the influence of the initial grain boundaries on the recrystallization kinetics and to incorporate the misorientation dependency of the low angle grain boundary mobility which strongly influences the orientation distribution in the resulting microstructure.
Reddy, C. J.
1998-01-01
An implementation of the Model Based Parameter Estimation (MBPE) technique is presented for obtaining the frequency response of the Radar Cross Section (RCS) of arbitrarily shaped, three-dimensional perfect electric conductor (PEC) bodies. An Electric Field Integral Equation (EFTE) is solved using the Method of Moments (MoM) to compute the RCS. The electric current is expanded in a rational function and the coefficients of the rational function are obtained using the frequency derivatives of the EFIE. Using the rational function, the electric current on the PEC body is obtained over a frequency band. Using the electric current at different frequencies, RCS of the PEC body is obtained over a wide frequency band. Numerical results for a square plate, a cube, and a sphere are presented over a bandwidth. Good agreement between MBPE and the exact solution over the bandwidth is observed.
Sun, Shuh-Ping; Hsu, Ko-Wen; Chen, Jing-Shyr
2008-05-01
Cosmetic doctor utilizes the position, size and shapes of female's breast to judge whether the breast is under steady-state condition after breast implant plastic surgery. Since, doctor evaluates the breast condition with the subjective discrimination (such as vision, sense of touch) without using the objective physical parameters auxiliary. This study uses the 3D optics scanner editing 3D image to obtain full-scale 3D female breasts image. The CAD system converts the breast position, size and shapes, as the length of the curve between UBL (upper breast line) and NBL (nipple base line), the length of the curve between NBL and LBL (lower breast line), breast volume and breasts congruence rate. The stability after the breast implant plastic surgery is one of the important successful indexes of plastic surgery, so with the continuity analysis the breast curve length, volume and congruence rate can let the doctor really grasp the stability of the breast after plastic surgery.
Cai, Shuang-yu; Wen, Lei; Jin, Ying
2017-10-01
Corrosion kinetic parameters play an important role in researchers' ability to understand and predict corrosion behavior. The corrosion kinetic parameters of structural steel Q345B specimens immersed in 3.5wt% NaCl solution for 1-2 h were determined using linear polarization resistance (LPR), Tafel-curve multiparameter fitting, electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation (EFM) methods. The advantages and disadvantages of each method were investigated and discussed through comparative investigation. Meanwhile, the average corrosion rate was examined using traditional coupon tests. The results showed that the corrosion current density values estimated by EFM at a base frequency of 0.001 Hz and those obtained by Tafel-curve four-parameter fitting (TC4) are similar and consistent with the results of coupon tests. Because of their slight perturbation of the corrosion system, EIS and EFM/TC4 in collaborative application are the recommended techniques for determining the kinetics and the corresponding parameters for the homogeneous corrosion of the naked metal. In our study of the electrochemical kinetics, we obtained much more abundant and accurate electrochemical kinetic parameters through the combined use of different electrochemical methods.
Hafeez Allan Agboola
2014-01-01
Pyrolysis of hydrocarbons and catalytic reforming of naphtha are important processes in petroleum refineries and petrochemical industries as they lead to production of light olefins, high octane gasoline, aromatics and so on. Thus, it is important to investigate their chemical kinetics in order to establish rate expressions or models for their reactions. In this research work, Monte-Carlo Simulation was applied to estimate kinetic parameters of two complex reactions: pyrolysis of n-Eicosane a...
Amanullah, Mohamed Jamal Bin; Adam, Tijjani; Dhahi, Th S.; Mohammed, Mohammed; Hashim, U.; Noriman, N. Z.; Dahham, Omar S.
2017-09-01
Silicon is the most important material in semiconductor industry. As nano-devices shrink in size, the conventional understanding of electronic devices are no longer applicable as quantum effects start to play an important role for the behavior of the device. At the same time, when structures are approaching atomic scale, the precise fabrication by photo-lithographic techniques, for example, are not even applicable. Very often, the fabrication of regular structures rely on self-assembly is susceptible to fluctuations. Therefore, a deeper understanding to exploit the quantum behavior of nano-devices and precise control of building nano-structures are highly desired. Thus, genetic algorithm based on first principle analysis to optimize silicon nanowires electron and elastic properties is proposed. One nanometer (1nm) surface reconstruction by using genetic algorithm combined with ab-initio calculation is proposed. The SiNWs behavior to quasi-direct band gap transition with the decrease size and the band gap properties under different electrical voltage will be determined.
Directory of Open Access Journals (Sweden)
M. H. Denton
2008-03-01
Full Text Available Moments calculated from the ion distributions (~0–40 keV measured by the Cluster Ion Spectrometry (CIS instrument are combined with data from the Cluster Flux Gate Magnetometer (FGM instrument and used to characterise the bulk properties of the plasma in the near-Earth magnetosphere over five years (2001–2005. Results are presented in the form of 2-D xy, xz and yz GSM cuts through the magnetosphere using data obtained from the Cluster Science Data System (CSDS and the Cluster Active Archive (CAA. Analysis reveals the distribution of ~0–40 keV ions in the inner magnetosphere is highly ordered and highly responsive to changes in solar wind velocity. Specifically, elevations in temperature are found to occur across the entire nightside plasma sheet region during times of fast solar wind. We demonstrate that the nightside plasma sheet ion temperature at a downtail distance of ~12 to 19 Earth radii increases by a factor of ~2 during periods of fast solar wind (500–1000 km s−1 compared to periods of slow solar wind (100–400 km s−1. The spatial extent of these increases are shown in the xy, xz and yz GSM planes. The results from the study have implications for modelling studies and simulations of solar-wind/magnetosphere coupling, which ultimately rely on in situ observations of the plasma sheet properties for input/boundary conditions.
Biodegradation of malathion and evaluation of kinetic parameters using three bacterial species
Directory of Open Access Journals (Sweden)
S.R. Geed
2016-12-01
Full Text Available Efficacy of three different bacterial species for biodegradation of malathion and its secondary products have been investigated. The concentration range of malathion under investigation was 25–200 mg⋅L−1. It has been observed that Pseudomonas putida was found to be most efficient for degradation of malathion. The removal of malathion was 72% at its concentration of 125 mg⋅L−1. The optimum parameters were studied for all three bacterial species in batch mode. The average values of Ks and μmax were obtained for all these species for degradation of malathion. Results indicate that P. putida has high degradation potential than Rhodoccocus rhodochrous and Sphingomonas sp. The degradation of P. putida was maximum at concentration of 125 mg⋅L−1, pH and temperature at 7 ± 0.2, 80 °C respectively. Metabolites were obtained using GCMS analysis.
Calculation of DSSC parameters based on ZnO nanorod/TiO2 mesoporous photoanode
Safriani, L.; Nurrida, A.; Mulyana, C.; Susilawati, T.; Bahtiar, A.; Aprilia, A.
2017-07-01
Photoanode of dye sensitized solar cell (DSSC) plays an important role as electron transport media to accept photogenerated electron from excited state of dye. There are several physical properties that are required from photoanode of DSSC. It should be highly transparent, have large surface area, has a conduction band lower than LUMO of dye molecule, has high charge carrier mobility and finally has a good stability in redox electrolyte process. In this work, DSSC with structure FTO/ZnO nanorod/TiO2 mesoporous/Ru-dye/gel electrolyte/ Pt/FTO has been fabricated. In order to modified the structures of photoanode, ZnO nanorod was grown on aluminium doped ZnO seed layer by variation concentration of Al (0 wt%, 0.5 wt% and 1.0 wt%). Zinc nitrate hexahydrate and hexamethylenetetramine used as raw materials for ZnO nanorod growth solution and deposited by self-assembly methods on FTO/Al doped ZnO seed layer. It is then followed by deposition of titania (TiO2) paste by screen printing methods. DSSC parameters i.e. ideally factor (n), series resistance (RS ), and shunt resistance (RSH ) was derived from current density-voltage (I-V) curve using the simplify equation of ideal diode model. The influences of ZnO photoanode structures to the solar cell performance will be completely discussed.
Recommended environmental dose calculation methods and Hanford-specific parameters. Revision 2
Energy Technology Data Exchange (ETDEWEB)
Schreckhise, R.G.; Rhoads, K.; Napier, B.A.; Ramsdell, J.V. [Pacific Northwest Lab., Richland, WA (United States); Davis, J.S. [Westinghouse Hanford Co., Richland, WA (United States)
1993-03-01
This document was developed to support the Hanford Environmental Dose overview Panel (HEDOP). The Panel is responsible for reviewing all assessments of potential doses received by humans and other biota resulting from the actual or possible environmental releases of radioactive and other hazardous materials from facilities and/or operations belonging to the US Department of Energy on the Hanford Site in south-central Washington. This document serves as a guide to be used for developing estimates of potential radiation doses, or other measures of risk or health impacts, to people and other biota in the environs on and around the Hanford Site. It provides information to develop technically sound estimates of exposure (i.e., potential or actual) to humans or other biotic receptors that could result from the environmental transport of potentially harmful materials that have been, or could be, released from Hanford operations or facilities. Parameter values and information that are specific to the Hanford environs as well as other supporting material are included in this document.
Gubchenko, V. M.
2015-12-01
The formation of magnetic structures in moving hot solar coronal plasma and hot collisionless laser-produced plasma, as determined by nonlinear criteria for weak and strong magnetization on the basis of the friction parameter Γ B and Alfven number M A, is considered within the Vlasov and Maxwell equations in the second part of the work. The flow velocities are lower then the thermal electron velocity. The energy and pulse anisotropy parameters of a flow, which determine its electromagnetic properties in the Cherenkov resonance line, are calculated by shape of particle distribution function (PDF). The ratio of these parameters is the Q-factor G V ; it characterizes the electromagnetic properties of a plasma flow and is expressed via the ratio of diamagnetic and resistive current densities or via the ratio of irregular and diamagnetic plasma scales. A particle flow is similar to a conductive medium at G V ≪ 1 and a diamagnetic medium at G V ≫ 1. The following cases are considered. (1) A plasma flow is specified by an isotropic PDF and interacts with distributed magnetization. Expressions for anisotropy parameters are derived, 3D field structures in the tail wake are found, and a possibility of topological reconstruction into a compact state under variation in the parameter G V is shown. (2) A plasma flow is specified by an isotropic PDF; a steady-state diamagnetic current layer, characterized by an anisotropic PDF, is immersed inside it. The system is in the diamagnetic state G ≫ 1. The generalized anisotropy parameter is calculated and a possibility of the excitation of three types of diamagnetic structures with low resistive currents is shown. (3) The nonlinear dynamics of anisotropic quasi-current-free plasma ( G =-1), in which the diamagnetic and resistive current densities locally compensate each other in the phase space of particle velocities, is studied. This dynamics is implemented in the long wavelength limit in plasma with an anisotropic PDF.
Gritsyk, Pavel; Somov, Boris
2016-04-01
The limb white-light solar flare M7.7 class was observed at the 19 July 2012 at 05:58UT by RHESSI, GOES and SDO with high spectral, spatial and temporal resolution. These new data make possible to test modern models of solar flares. The flare, which considered here, locates in the picture plane, so we well see two different hard X-ray sources: footpoint and above-the-loop-top. The loop was observed in whit-light and microwave wavelengths. The key part of the presented work is high accuracy kinetic model, which describe behavior of electrons in the target - solar flare loop. We interpret the footpoint source in approximation of the thick target model with reverse current and above-the-loop-top source - in the thin target approximation. The microwave spectrum in the range from 1 to 50 GHz was calculated. Our results fit well the observational data, particularly so important parameter as hard X-Ray spectral index. But intensity of emission of the coronal source was estimated incorrect, it was low than observed. This problem can be solved by taking into account effects of particles acceleration in the collapsing magnetic trap, when fast electrons receive additional energy without changing the index of their energy spectrum. In the result we have flux ~ 5 1010 erg cm-2 s-1 for electrons with energies more then 15 keV, that ~ 5 times larger then in the case classical thick target model. Accordingly , so high flux of electrons to the Chromosphere provides effective heating of the cold plasma in the target, but the reverse current electric field restrict depth of the electron penetration. Received in this work estimates may be used for interpretation of the solar flare optical source formation and evolution.
Garger, Evgenii K; Meisenberg, Oliver; Odintsov, Oleksiy; Shynkarenko, Viktor; Tschiersch, Jochen
2013-10-15
Nuclear fuel particles of Chernobyl origin are carriers of increased radioactivity (hot particles) and are still present in the atmosphere of the Chernobyl exclusion zone. Workers in the zone may inhale these particles, which makes assessment necessary. The residence time in the lungs and the transfer in the blood of the inhaled radionuclides are crucial for inhalation dose assessment. Therefore, the dissolution of several kinds of nuclear fuel particles from air filters sampled in the Chernobyl exclusion zone was studied. For this purpose filter fragments with hot particles were submersed in simulated lung fluids (SLFs). The activities of the radionuclides (137)Cs, (90)Sr, (239+240)Pu and (241)Am were measured in the SLF and in the residuum of the fragments by radiometric methods after chemical treatment. Soluble fractions as well as dissolution rates of the nuclides were determined. The influence of the genesis of the hot particles, represented by the (137)Cs/(239+240)Pu ratio, on the availability of (137)Cs was demonstrated, whereas the dissolution of (90)Sr, (239+240)Pu and (241)Am proved to be independent of genesis. No difference in the dissolution of (137)Cs and (239+240)Pu was observed for the two applied types of SLF. Increased solubility was found for smaller hot particles. A two-component exponential model was used to describe the dissolution of the nuclides as a function of time. The results were applied for determining individual inhalation dose coefficients for the workers at the Chernobyl construction site. Greater dose coefficients for the respiratory tract and smaller coefficients for the other organs were calculated (compared to ICRP default values). The effective doses were in general lower for the considered radionuclides, for (241)Am even by one order of magnitude. © 2013 Elsevier B.V. All rights reserved.
Structural, electric and kinetic parameters of ternary alloys of GeSbTe
Energy Technology Data Exchange (ETDEWEB)
Morales-Sanchez, E. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Libramiento Norponiente 2000, Ap. Postal 13, Juriquilla, Queretaro, C. P. 76230, (Mexico)]. E-mail: m6007@ciateq.net.mx; Prokhorov, E.F. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Libramiento Norponiente 2000, Ap. Postal 13, Juriquilla, Queretaro, C. P. 76230, (Mexico); Gonzalez-Hernandez, J. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Libramiento Norponiente 2000, Ap. Postal 13, Juriquilla, Queretaro, C. P. 76230, (Mexico); Mendoza-Galvan, A. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Libramiento Norponiente 2000, Ap. Postal 13, Juriquilla, Queretaro, C. P. 76230, (Mexico)
2005-01-03
Thin amorphous films of GeSbTe have been widely employed in the technology used for phase change optical memory or compact disks. In this article, we report on measurements of resistance, transmittance, and X-ray diffraction in thin films with stoichiometric compositions of Ge{sub 1}Sb{sub 4}Te{sub 7}, Ge{sub 1}Sb{sub 2}Te{sub 4}, Ge{sub 2}Sb{sub 2}Te{sub 5}, and Ge{sub 4}Sb{sub 1}Te{sub 5.} The resistivity, lattice constant, and the temperature at which transformation from the amorphous phase to the cubic crystalline structure occurs were calculated for each stoichiometric composition, and the energy activation was determined, applying Kissinger's model. It was found that the Ge{sub 4}Sb{sub 1}Te{sub 5} composition has the highest crystallization temperature (425 K), the highest resistivity (0.178 {omega} cm), the greatest E{sub a} (3.09 eV), and the lowest lattice constant (a=5.975 A) in the cubic phase at 170 deg C.
Dosimetric and kinetic parameters of lithium cadmium borate glasses doped with rare earth ions
Directory of Open Access Journals (Sweden)
J. Anjaiah
2014-10-01
Full Text Available Thermoluminescence (TL characteristics of X-ray irradiated pure and doped with four different rare earth ions (viz., Pr3+, Nd3+, Sm3+ and Eu3+ Li2O–Cdo–B2O3 glasses have been studied in the temperature range 303–573 K; the pure glass has exhibited single TL peak at 466 K. When this glass is doped with different rare earth ions no additional peaks are observed but the glow peak temperature of the existing glow peak shifted gradually towards higher temperatures with gain in intensity of TL light output. The area under the glow curve is found to be maximum for Eu3+ doped glasses. The trap depth parameters associated with the observed TL peaks have been evaluated using Chen's formulae. The possible use of these glasses in radiation dosimetry has been described. The result clearly showed that europium doped cadmium borate glass has a potential to be considered as the thermoluminescence dosimeter.
Energy Technology Data Exchange (ETDEWEB)
Gallegos, A.A. [CICATA-IPN, Legaria 694, Col. Irrigacion, 11500 Mexico D.F. (Mexico); Khaidukov, N.M. [Kurnakov Institute of General and Inorganic Chemistry, Moscow (Russian Federation); Azorin, J. [UAM-I, 09340 Mexico D.F. (Mexico)
2005-07-01
In this work the K{sub 2}Y doped materials with percentages of 0.01 and 0.2 of F{sub 5} and, 0.8 and 0.99 of Tb{sup 3+} were studied to determine the kinetic parameters (activation energy and frequency factor) of TL peaks with the purpose of comparing those sensitive qualities of the materials at the doping with TR and their candidacy for tests of TL dosimetry (linearity of the response with the absorbed dose and the reproducibility of the measures of the dose). The samples were irradiated with a beta source of {sup 90} Sr/{sup 90} Y, to ambient temperature, giving its a dose of 236.6 mGy, later the kinetic parameters with different experimental procedures were determined: isothermal decay to ambient temperature and erased of peaks not desired to greater temperature than the ambient. The glow curves (TL curves) were obtained with an TL analyzer Harshaw 4000, with interface to CPU for the handling of the data of the curves, which were treated with the curve form method and the models of: Chen first approach and Chen modified, corrected Lushchik approach and Grossweiner approach, to calculate the kinetic parameters of the sample. (Author)
Kinetic parameters and intraindividual fluctuations of ochratoxin A plasma levels in humans
Energy Technology Data Exchange (ETDEWEB)
Studer-Rohr, I. [Inst. of Toxicology, Swiss Federal Inst. of Tech. and Univ. of Zurich, Schwerzenbach (Switzerland); Dept. of Food Science, Swiss Federal Inst. of Tech., Zurich (Switzerland); Schlatter, J. [Toxicology Section, Div. of Food Science, Swiss Federal Office of Public Health, Zurich (Switzerland); Dietrich, D.R. [Dept. of Environmental Toxicology, Univ. of Konstanz, Konstanz (Germany); Inst. of Toxicology, Swiss Federal Inst. of Tech. and Univ. of Zurich, Schwerzenbach (Switzerland)
2000-11-01
The mycotoxin ochratoxin A (OTA) is a rodent carcinogen produced by species of the ubiquitous fungal genera Aspergillus and Penicillium. OTA is found in a variety of food items and as a consequence is also found in human plasma (average concentrations found in this study: 0.1-1 ng OTA/ml plasma). To improve the scientific basis for cancer risk assessment the toxicokinetic profile of OTA was studied in one human volunteer following ingestion of 395 ng {sup 3}H-labeled OTA (3.8 {mu}Ci). A two-compartment open model consisting of a central compartment was found to best describe the in vivo data. This two-compartment model consisted of a fast elimination and distribution phase (T{sub 1/2} about 20 h) followed by a slow elimination phase (renal clearance about 0.11 ml/min.) and a calculated plasma half-life of 35.55 days. This half-life was approximately eight times longer than that determined previously in rats. In addition, the intraindividual fluctuation of OTA plasma levels was investigated in eight individuals over a period of 2 months. The concentrations determined ranged between 0.2 and 0.9 ng OTA/ml plasma. The plasma levels in some individuals remained nearly constant over time, while others varied considerably (e.g. increase of 0.4 ng/ml within 3 days, decrease of 0.3 ng/ml within 5 days) during the observation period. This intraindividual fluctuation in OTA plasma levels, which may represent differences in OTA exposure and/or metabolism, as well as the large difference in plasma half-life in humans compared to rats must be taken into consideration when the results of rat cancer study data are extrapolated to humans for risk assessment purposes. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Hein, O.; Jess, A. [Technische Hochschule Aachen (Germany). Inst. fuer Technische Chemie und Makromolekulare Chemie
2000-01-01
The determination of kinetic constants of heterogeneous reactions is usually performed in tubular flow reactors under isothermal and stationary reaction conditions. This is often time-consuming and difficult. For example, in case of strong exothermic reactions, temperature gradients up to the ignition of the fixed-bed are hard to avoid, and therefore expensive reactors with internal or external gas recycle are needed. The effect of ignition can also be used to characterize the reactivity of solid fuels and the activity of catalysts, respectively. A well-known method for a simple, fast and accurate determination of the ignition temperature in a lab-scale tubular flow reactor is already described in literature. Yet, the ignition point method is up to now only used as a qualitative measure for the (relative) reactivity of solid fuels and activity of catalysts. Therefore, an attempt was made to extend this method towards a quantitative characterization of the kinetics of exothermic heterogeneous reaction systems, i.e. for a determination of the activation energy and the preexponential factor. The basic idea is thereby to alter the ignition point by a defined variation of the operation conditions such as particle diameter, heating rate as well as of the composition and flow rate of the reacting gas mixture. The resulting data are then used to calculate the kinetic constants based on the theory of ignition of exothermic reactions. The combustion of different cokes as well as of carbon deposits on a Pt-catalyst were selected as model reactions for gas/solid-reactions. In addition, the oxidation of methane on a Pt-catalyst was investigated. The experiments on the influence of the operation conditions show that the gas composition - in case of combustion of coke the oxygen content - has the strongest influence on the ignition temperature. This method is therefore very suitable to determine kinetic constants. To prove the accuracy of this method, the kinetic data were also
Yang, Jing; Youssef, Mostafa; Yildiz, Bilge
2018-01-01
In this work, we quantify oxygen self-diffusion in monoclinic-phase zirconium oxide as a function of temperature and oxygen partial pressure. A migration barrier of each type of oxygen defect was obtained by first-principles calculations. Random walk theory was used to quantify the diffusivities of oxygen interstitials by using the calculated migration barriers. Kinetic Monte Carlo simulations were used to calculate diffusivities of oxygen vacancies by distinguishing the threefold- and fourfold-coordinated lattice oxygen. By combining the equilibrium defect concentrations obtained in our previous work together with the herein calculated diffusivity of each defect species, we present the resulting oxygen self-diffusion coefficients and the corresponding atomistically resolved transport mechanisms. The predicted effective migration barriers and diffusion prefactors are in reasonable agreement with the experimentally reported values. This work provides insights into oxygen diffusion engineering in Zr O2 -related devices and parametrization for continuum transport modeling.
Energy Technology Data Exchange (ETDEWEB)
Bunting, Bruce G [ORNL
2012-10-01
The automotive and engine industries are in a period of very rapid change being driven by new emission standards, new types of after treatment, new combustion strategies, the introduction of new fuels, and drive for increased fuel economy and efficiency. The rapid pace of these changes has put more pressure on the need for modeling of engine combustion and performance, in order to shorten product design and introduction cycles. New combustion strategies include homogeneous charge compression ignition (HCCI), partial-premixed combustion compression ignition (PCCI), and dilute low temperature combustion which are being developed for lower emissions and improved fuel economy. New fuels include bio-fuels such as ethanol or bio-diesel, drop-in bio-derived fuels and those derived from new crude oil sources such as gas-to-liquids, coal-to-liquids, oil sands, oil shale, and wet natural gas. Kinetic modeling of the combustion process for these new combustion regimes and fuels is necessary in order to allow modeling and performance assessment for engine design purposes. In this research covered by this CRADA, ORNL developed and supplied experimental data related to engine performance with new fuels and new combustion strategies along with interpretation and analysis of such data and consulting to Reaction Design, Inc. (RD). RD performed additional analysis of this data in order to extract important parameters and to confirm engine and kinetic models. The data generated was generally published to make it available to the engine and automotive design communities and also to the Reaction Design Model Fuels Consortium (MFC).
Energy Technology Data Exchange (ETDEWEB)
Raposo, Maria, E-mail: mfr@fct.unl.pt; Monteiro Timóteo, Ana Rita; Ribeiro, Paulo A. [CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, UNL, Campus de Caparica, 2829-516 Caparica (Portugal); Ferreira, Quirina [CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, UNL, Campus de Caparica, 2829-516 Caparica (Portugal); Instituto de Telecomunicações, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, P-1049-001 Lisboa (Portugal); Botelho do Rego, Ana Maria [Centro de Química-Física Molecular and IN, Complexo Interdisciplinar, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisboa (Portugal)
2015-09-21
Photo induced birefringent materials can be used to develop optical and conversion energy devices, and consequently, the study of the variables that influences the creation and relaxation of birefringence should be carefully analyzed. In this work, the parameters of birefringence creation and relaxation kinetics curves obtained on layer-by-layer (LBL) films, prepared from azo-polyectrolyte poly[1-[4-(3-carboxy-4 hydroxyphenylazo) benzene sulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) and poly(allylamine hydrochloride)(PAH), are related with the presence of counterions and the degree of ionization of the polyelectrolytes. Those kinetics curves obtained on PAH/PAZO LBL films, prepared from PAH solutions with different pHs and maintaining the pH of PAZO solution constant at pH = 9, were analyzed taking into account the films composition which was characterized by X-ray photoelectron spectroscopy. The creation and relaxation birefringence curves are justified by two processes: one associated to local mobility of the azobenzene with a characteristic time 30 s and intensity constant and other associated with polymeric chains mobility with the characteristic time and intensity decreasing with pH. These results allow us to conclude that the birefringence creation process, associated to local mobility of azobenzenes is independent of the degree of ionization and of number of counterions or co-ions present while the birefringence creation process associated to mobility of chains have its characteristic time and intensity dependent of both degree of ionization and number of counterions. The birefringence relaxation processes are dependent of the degree of ionization. The analysis of the films composition revealed, in addition, the presence of a protonated secondary or tertiary amine revealing that PAZO may have positive charges and consequently a zwitterionic behavior.
Energy Technology Data Exchange (ETDEWEB)
Matei, Iulia; Ionescu, Sorana [Department of Physical Chemistry, Faculty of Chemistry, University of Bucharest, Bd. Regina Elisabeta 4-12, 030018 Bucharest (Romania); Hillebrand, Mihaela, E-mail: mihh@gw-chimie.math.unibuc.ro [Department of Physical Chemistry, Faculty of Chemistry, University of Bucharest, Bd. Regina Elisabeta 4-12, 030018 Bucharest (Romania)
2011-08-15
The interaction between fisetin, an antioxidant and neuroprotective flavonoid, and human serum albumin (HSA) is investigated by means of fluorescence (steady-state, synchronous, time-resolved) and circular dichroism (CD) spectroscopy. The formation of a 1:1 complex with a constant of about 10{sup 5} M{sup -1} was evidenced. Foerster's resonance energy transfer and competitive binding with site markers warfarin and ibuprofen were considered and discussed. Changes in the CD band of HSA indicate a decrease in the {alpha}-helix content upon binding. An induced CD signal for bound fisetin was observed and rationalized in terms of density functional theory calculations. - Highlights: > Fisetin-BSA system was studied by fluorescence spectroscopy. > Binding parameters, association constant and number of sites were estimated. > Binding site of fisetin was identified by competitive experiments. > Conformational changes in HSA and fisetin were evidenced by circular dichroism. > TDDFT calculated CD spectra supported the experimental data.
Kraan, GPB; Dullaart, RPF; Pratt, JJ; Wolthers, BG; de Bruin, R
1997-01-01
The kinetics of cortisol in the serum of 4 healthy men were studied following single i.v. doses of 2 and 0.8 mg of cortisol. The disappearance of cortisol was determined by blood sampling frequently over 2.5 h and analysing the apparently biexponential cortisol decay. The main results, shown as the
Directory of Open Access Journals (Sweden)
Mkrtychev Oleg Vartanovich
Full Text Available In the article the problem of calculation of a construction basis system in case of earthquake is considered taking into account casual properties of basis soil in various points of the soil body. As a stochastic function in the calculation of linearly deformable basis, the deformation module, which accepts different values in the direction x, y, z, was chosen. In the calculation of the system on non-linearly deformable basis as incidentally distributed sizes the following parameters were accepted: deformation module, shear modulus, specific adhesion, angle of internal friction. The authors of the article offer to consider initial seismic influence in the form of casual stationary process. In order to solve such problems modern software systems are proposed that solve differential equations of motion via direct integration with explicit schemes. The calculation in this case will be held on the synthesized accelerograms. A short review of the task solution of the beam lying on elastic basis, which was received by D.N. Sobolev at casual distribution of pastel coefficient in the direction x, is provided in article. In order to define the objective, D.N. Sobolev gives expressions for a population mean and correlation function of stochastic function. As a result of the task solution population means and dispersions of function of movements and its derivatives were received. The problem formulation considered in the article is more complicated, but at the same time important from a practical standpoint.
Energy Technology Data Exchange (ETDEWEB)
Mandlik, Nandkumar, E-mail: ntmandlik@gmail.com [Department of Physics, University of Pune, Ganeshkhind, Pune -411007, India and Department of Physics, Fergusson College, Pune- 411004 (India); Patil, B. J.; Bhoraskar, V. N.; Dhole, S. D. [Department of Physics, University of Pune, Ganeshkhind, Pune -411007 (India); Sahare, P. D. [Department of Physics and Astrophysics, University of Delhi, Delhi- 110007 (India)
2014-04-24
Nanorods of CaSO{sub 4}: Dy having diameter 20 nm and length 200 nm have been synthesized by the chemical coprecipitation method. These samples were irradiated with gamma radiation for the dose varying from 0.1 Gy to 50 kGy and their TL characteristics have been studied. TL dose response shows a linear behavior up to 5 kGy and further saturates with increase in the dose. A Computerized Glow Curve Deconvolution (CGCD) program was used for the analysis of TL glow curves. Trapping parameters for various peaks have been calculated by using CGCD program.
Energy Technology Data Exchange (ETDEWEB)
La Fontaine, M; Bradshaw, T [University of Wisconsin, Madison, Wisconsin (United States); Kubicek, L [University of Florida, Gainesville, Florida (United States); Forrest, L [University of Wisconsin-Madison, Madison, Wisconsin (United States); Jeraj, R [University of Wisconsin, Madison, WI (United States)
2014-06-15
Purpose: Regions of poor perfusion within tumors may be associated with higher hypoxic levels. This study aimed to test this hypothesis by comparing measurements of hypoxia from Cu-ATSM PET to vasculature kinetic parameters from DCE-CT kinetic analysis. Methods: Ten canine patients with sinonasal tumors received one Cu-ATSM PET/CT scan and three DCE-CT scans prior to treatment. Cu-ATSM PET/CT and DCE-CT scans were registered and resampled to matching voxel dimensions. Kinetic analysis was performed on DCE-CT scans and for each patient, the resulting kinetic parameter values from the three DCE-CT scans were averaged together. Cu-ATSM SUVs were spatially correlated (r{sub spatial}) on a voxel-to-voxel basis against the following DCE-CT kinetic parameters: transit time (t{sub 1}), blood flow (F), vasculature fraction (v{sub 1}), and permeability (PS). In addition, whole-tumor comparisons were performed by correlating (r{sub ROI}) the mean Cu-ATSM SUV (SUV{sub mean}) with median kinetic parameter values. Results: The spatial correlations (r{sub spatial}) were poor and ranged from -0.04 to 0.21 for all kinetic parameters. These low spatial correlations may be due to high variability in the DCE-CT kinetic parameter voxel values between scans. In our hypothesis, t{sub 1} was expected to have a positive correlation, while F was expected to have a negative correlation to hypoxia. However, in wholetumor analysis the opposite was found for both t{sub 1} (r{sub ROI} = -0.25) and F (r{sub ROI} = 0.56). PS and v{sub 1} may depict angiogenic responses to hypoxia and found positive correlations to Cu-ATSM SUV for PS (r{sub ROI} = 0.41), and v{sub 1} (r{sub ROI} = 0.57). Conclusion: Low spatial correlations were found between Cu-ATSM uptake and DCE-CT vasculature parameters, implying that poor perfusion is not associated with higher hypoxic regions. Across patients, the most hypoxic tumors tended to have higher blood flow values, which is contrary to our initial hypothesis. Funding
Lumping procedure for a kinetic model of catalytic naphtha reforming
Directory of Open Access Journals (Sweden)
H. M. Arani
2009-12-01
Full Text Available A lumping procedure is developed for obtaining kinetic and thermodynamic parameters of catalytic naphtha reforming. All kinetic and deactivation parameters are estimated from industrial data and thermodynamic parameters are calculated from derived mathematical expressions. The proposed model contains 17 lumps that include the C6 to C8+ hydrocarbon range and 15 reaction pathways. Hougen-Watson Langmuir-Hinshelwood type reaction rate expressions are used for kinetic simulation of catalytic reactions. The kinetic parameters are benchmarked with several sets of plant data and estimated by the SQP optimization method. After calculation of deactivation and kinetic parameters, plant data are compared with model predictions and only minor deviations between experimental and calculated data are generally observed.
Bénichou, O; Chevalier, C; Klafter, J; Meyer, B; Voituriez, R
2010-06-01
It has long been appreciated that the transport properties of molecules can control reaction kinetics. This effect can be characterized by the time it takes a diffusing molecule to reach a target-the first-passage time (FPT). Determining the FPT distribution in realistic confined geometries has until now, however, seemed intractable. Here, we calculate this FPT distribution analytically and show that transport processes as varied as regular diffusion, anomalous diffusion, and diffusion in disordered media and fractals, fall into the same universality classes. Beyond the theoretical aspect, this result changes our views on standard reaction kinetics and we introduce the concept of 'geometry-controlled kinetics'. More precisely, we argue that geometry-and in particular the initial distance between reactants in 'compact' systems-can become a key parameter. These findings could help explain the crucial role that the spatial organization of genes has in transcription kinetics, and more generally the impact of geometry on diffusion-limited reactions.
Directory of Open Access Journals (Sweden)
Henry Arturo Bastidas Mora
2010-05-01
Full Text Available This article presents the properties of electric power networks for use as a channel for transmitting telecommunications signals. It starts by exploring the principles and theoretical basis for calculating power lines’ critical technical parameters, referring in detail to the following primary parameters: inductance, capacitance, conductance and resistance. It then deals with e secondary para- meters (most useful from a telecommunications perspective: characteristic impedance and propagation constant (the attenuation constant being the latter’s real component. Different topologies and low- and medium-tension aerial power line structures are verified; a mathematical model is then proposed to analyse their behaviour at high frequencies, extending to most aerial electric power distribution systems in Colombia. This work includes some of the results from previous research which was known as “U- sing power line telecommunications (PLT technology for designing a solution for accessing the broadband internet in rural areas of Colombia” by the present author and the Pilot University of Colombia. The proposed mathematical model provides a tool for making theoretical calculations applicable to PLT.
Nikezic, D.; Yu, K. N.
2006-01-01
A computer program called TRACK_TEST for calculating parameters (lengths of the major and minor axes) and plotting profiles in nuclear track materials resulted from light-ion irradiation and subsequent chemical etching is described. The programming steps are outlined, including calculations of alpha-particle ranges, determination of the distance along the particle trajectory penetrated by the chemical etchant, calculations of track coordinates, determination of the lengths of the major and minor axes and determination of the contour of the track opening. Descriptions of the program are given, including the built-in V functions for the two commonly employed nuclear track materials commercially known as LR 115 (cellulose nitrate) and CR-39 (poly allyl diglycol carbonate) irradiated by alpha particles. Program summaryTitle of the program:TRACK_TEST Catalogue identifier:ADWT Program obtainable from:CPC Program Library, Queen's University of Belfast, N. Ireland Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADWT Computer:Pentium PC Operating systems:Windows 95+ Programming language:Fortran 90 Memory required to execute with typical data:256 MB No. of lines in distributed program, including test data, etc.: 2739 No. of bytes in distributed program, including test data, etc.:204 526 Distribution format:tar.gz External subprograms used:The entire code must be linked with the MSFLIB library Nature of problem: Fast heavy charged particles (like alpha particles and other light ions etc.) create latent tracks in some dielectric materials. After chemical etching in aqueous NaOH or KOH solutions, these tracks become visible under an optical microscope. The growth of a track is based on the simultaneous actions of the etchant on undamaged regions (with the bulk etch rate V) and along the particle track (with the track etch rate V). Growth of the track is described satisfactorily by these two parameters ( V and V). Several models have been presented in the past describing
Directory of Open Access Journals (Sweden)
Filipović Ivan
2011-01-01
Full Text Available The main role in air/fuel mixture formation at the IC diesel engines has the energy introduced by fuel into the IC engine that is the characteristics of spraying fuel into the combustion chamber. The characteristic can be defined by the spray length, the spray cone angle, the physical and the chemical structure of fuel spray by different sections. Having in mind very complex experimental setups for researching in this field, the mentioned characteristics are mostly analyzed by calculations. There are two methods in the literature, the first based on use of the semi-empirical expressions (correlations and the second, the calculations of spray characteristics by use of very complex mathematical methods. The second method is dominant in the modern literature. The main disadvantage of the calculation methods is a correct definition of real state at the end of the nozzle orifice (real boundary conditions. The majority of the researchers in this field use most frequently the coefficient of total losses inside the injector. This coefficient depends on injector design, as well as depends on the level of fuel energy and fuel energy transformation along the injector. Having in mind the importance of the real boundary conditions, the complex methods for calculation of the fuel spray characteristics should have the calculation of fuel flows inside the injector and the calculation of spray characteristics together. This approach is a very complex numerical problem and there are no existing computer programs with satisfactory calculation results. Analysis of spray characteristics by use of the semi-empirical expressions (correlations is presented in this paper. The special attention is dedicated to the analysis of the constant in the semi-empirical expressions and influence parameters on this constant. Also, the method for definition of realistic boundary condition at the end of the nozzle orifice is presented in the paper. By use of this method completely
Li, An; Ziehr, Jessica L; Johnson, Kenneth A
2017-04-21
Recent studies have demonstrated the dominant role of induced fit in enzyme specificity of HIV reverse transcriptase and many other enzymes. However, relevant thermodynamic parameters are lacking, and equilibrium thermodynamic methods are of no avail because the key parameters can only be determined by kinetic measurement. By modifying KinTek Explorer software, we present a new general method for globally fitting data collected over a range of substrate concentrations and temperatures and apply it to HIV reverse transcriptase. Fluorescence stopped-flow methods were used to record the kinetics of enzyme conformational changes that monitor nucleotide binding and incorporation. The nucleotide concentration dependence was measured at temperatures ranging from 5 to 37 °C, and the raw data were fit globally to derive a single set of rate constants at 37 °C and a set of activation enthalpy terms to account for the kinetics at all other temperatures. This comprehensive analysis afforded thermodynamic parameters for nucleotide binding ( K d , Δ G , Δ H , and Δ S at 37 °C) and kinetic parameters for enzyme conformational changes and chemistry (rate constants and activation enthalpy). Comparisons between wild-type enzyme and a mutant resistant to nucleoside analogs used to treat HIV infections reveal that the ground state binding is weaker and the activation enthalpy for the conformational change step is significantly larger for the mutant. Further studies to explore the structural underpinnings of the observed thermodynamics and kinetics of the conformational change step may help to design better analogs to treat HIV infections and other diseases. Our new method is generally applicable to enzyme and chemical kinetics. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.
Directory of Open Access Journals (Sweden)
Huang Can
2014-08-01
Full Text Available In the present paper, a numerical model combining radiation and conduction for porous materials is developed based on the finite volume method. The model can be used to investigate high-temperature thermal insulations which are widely used in metallic thermal protection systems on reusable launch vehicles and high-temperature fuel cells. The effective thermal conductivities (ECTs which are measured experimentally can hardly be used separately to analyze the heat transfer behaviors of conduction and radiation for high-temperature insulation. By fitting the effective thermal conductivities with experimental data, the equivalent radiation transmittance, absorptivity and reflectivity, as well as a linear function to describe the relationship between temperature and conductivity can be estimated by an inverse problems method. The deviation between the calculated and measured effective thermal conductivities is less than 4%. Using the material parameters so obtained for conduction and radiation, the heat transfer process in multilayer thermal insulation (MTI is calculated and the deviation between the calculated and the measured transient temperatures at a certain depth in the multilayer thermal insulation is less than 6.5%.
van Noorden, C. J.; Bahns, S.; Köhler, A.
1997-01-01
Kinetic parameters of glucose-6-phosphate dehydrogenase (G6PDH) and phosphogluconate dehydrogenase (PGDH) were determined in situ in livers of marine flatfish flounder that were caught in unpolluted areas in the open sea and in the highly polluted river Elbe (Germany). Analysis was performed
Jussier, Delphine; Dubé Morneau, Amélie; Mira de Orduña, Ramón
2006-01-01
Inoculating grape musts with wine yeast and lactic acid bacteria (LAB) concurrently in order to induce simultaneous alcoholic fermentation (AF) and malolactic fermentation (MLF) can be an efficient alternative to overcome potential inhibition of LAB in wines because of high ethanol concentrations and reduced nutrient content. In this study, the simultaneous inoculation of yeast and LAB into must was compared with a traditional vinification protocol, where MLF was induced after completion of AF. For this, two suitable commercial yeast-bacterium combinations were tested in cool-climate Chardonnay must. The time courses of glucose and fructose, acetaldehyde, several organic acids, and nitrogenous compounds were measured along with the final values of other key wine parameters. Sensory evaluation was done after 12 months of storage. The current study could not confirm a negative impact of simultaneous AF/MLF on fermentation success and kinetics or on final wine parameters. While acetic acid concentrations were slightly increased in wines after simultaneous AF/MLF, the differences were of neither practical nor legal significance. No statistically significant differences were found with regard to the final values of pH or total acidity and the concentrations of ethanol, acetaldehyde, glycerol, citric and lactic acids, and the nitrogen compounds arginine, ammonia, urea, citrulline, and ornithine. Sensory evaluation by a semiexpert panel confirmed the similarity of the wines. However, simultaneous inoculation led to considerable reductions in overall fermentation durations. Furthermore, differences of physiological and microbiological relevance were found. Specifically, we report the vinification of "super-dry" wines devoid of glucose and fructose after simultaneous inoculation of yeast and bacteria.
Comparison of dual-echo DSC-MRI- and DCE-MRI-derived contrast agent kinetic parameters.
Quarles, C Chad; Gore, John C; Xu, Lei; Yankeelov, Thomas E
2012-09-01
The application of dynamic susceptibility contrast (DSC) MRI methods to assess brain tumors is often confounded by the extravasation of contrast agent (CA). Disruption of the blood-brain barrier allows CA to leak out of the vasculature leading to additional T(1), T(2) and T(2) relaxation effects in the extravascular space, thereby affecting the signal intensity time course in a complex manner. The goal of this study was to validate a dual-echo DSC-MRI approach that separates and quantifies the T(1) and T(2) contributions to the acquired signal and enables the estimation of the volume transfer constant, K(trans), and the volume fraction of the extravascular extracellular space, v(e). To test the validity of this approach, DSC-MRI- and dynamic contrast enhanced (DCE) MRI-derived K(trans) and v(e) estimates were spatially compared in both 9L and C6 rat brain tumor models. A high degree of correlation (concordance correlation coefficients >0.83, Pearson's r>0.84) and agreement was found between the DSC-MRI- and DCE-MRI-derived measurements. These results indicate that dual-echo DSC-MRI can be used to simultaneously extract reliable DCE-MRI kinetic parameters in brain tumors in addition to conventional blood volume and blood flow metrics. Copyright © 2012 Elsevier Inc. All rights reserved.
Nam, Duck-Hyun; Kang, Ki-Hoon
2013-01-01
By evaluating microbial kinetic parameters of a pilot sludge blanket reactor (SBR) plant operated with an anaerobic sludge holding tank (SHT), it was found that the sludge production was reduced by 63.5%. According to the theory of uncoupling metabolism, the microorganisms were induced to the initial stage of the endogenous phase in SHT, which resulted in the reduction of yield coefficient. For the determination of optimal retention time in SHT without causing a significant decay of microorganisms, ammonia concentration was monitored with time at specific temperature and mixed liquor suspended solids concentrations. In a long-term (>1 yr) operation of the pilot plant, no deterioration of the effluent water quality was observed. Considering phosphorus removal, an extended sludge retention time of 60-70 days (due to the reduced yield coefficient) did not significantly affect the efficiency relative to typical biological nutrient removal (BNR) processes. According to the findings of this study, anaerobic SHT can be applied for BNR processes with reduced production of sludge, and this will help to minimize environmental and economic problems pertaining to the final disposal of sludge.
Yang, Kai-Min; Chiang, Po-Yuan
2017-03-28
Different biological sources of n -3 polyunsaturated fatty acids ( n -3 PUFA) in mainstream commercial products include algae and fish. Lipid oxidation in n -3 PUFA-rich oil is the most important cause of its deterioration. We investigated the kinetic parameters of n -3 PUFA-rich oil during oxidation via Rancimat (at a temperature range of 70~100 °C). This was done on the basis of the Arrhenius equation, which indicates that the activation energies ( E a) for oxidative stability are 82.84-96.98 KJ/mol. The chemical substrates of different oxidative levels resulting from oxidation via Rancimat at 80 °C were evaluated. At the initiation of oxidation, the tocopherols in the oil degraded very quickly, resulting in diminished protection against further oxidation. Then, the degradation of the fatty acids with n -3 PUFA-rich oil was evident because of decreased levels of PUFA along with increased levels of saturated fatty acids (SFA). The quality deterioration from n -3 PUFA-rich oil at the various oxidative levels was analyzed chemometrically. The anisidine value (p-AV, r: 0.92) and total oxidation value (TOTOX, r: 0.91) exhibited a good linear relationship in a principal component analysis (PCA), while oxidative change and a significant quality change to the induction period (IP) were detected through an agglomerative hierarchical cluster (AHC) analysis.
Directory of Open Access Journals (Sweden)
Karina Gomes Angilelli
2017-05-01
Full Text Available A mixture of vegetable oil and animal fat as raw materials was optimized by simplex-centroid mixture design to produce a type of biodiesel with good oxidative stability, flow properties and reaction yield. Further, kinetic and thermodynamic parameters of oxidation reaction were determined by the accelerated method at different temperatures. Biodiesel produced with sodium methoxide as catalyst presented 6.5°C of cloud point, 2.0°C of pour point, and oxidative stability at 110°C equal to 8.98h, with a reaction yield of 96.04%. Activation energy of the oxidation reaction was 81.03 kJ mol-1 for biodiesel produced with sodium hydroxide and 90.51 kJ mol-1 for sodium methoxide. The positive values for DH‡ and DG‡ indicate that the oxidation process is endothermic and endergonic. The less negative DS‡ for biodiesel produced with sodium methoxide (-28.87 JK-1 mol-1 showed that the process of degradation of this biofuel was slower than that produced with NaOH. The mixture of raw materials proposed, transesterified with the methoxide catalyst, resulted in a biofuel that resisted oxidation for longer periods, making unnecessary the addition of antioxidant
Herascu, Nicoleta; Najafi, Mehdi; Amunts, Alexey; Pieper, Jörg; Irrgang, Klaus-Dieter; Picorel, Rafael; Seibert, Michael; Zazubovich, Valter
2011-03-31
The parameters of barrier distributions on the protein energy landscape in the excited electronic state of the pigment/protein system have been determined by means of spectral hole burning for the lowest-energy pigments of CP43 core antenna complex and CP29 minor antenna complex of spinach Photosystem II (PS II) as well as of trimeric and monomeric LHCII complexes transiently associated with the pea Photosystem I (PS I) pool. All of these complexes exhibit sixty to several hundred times lower spectral hole burning yields as compared with molecular glassy solids previously probed by means of the hole growth kinetics measurements. Therefore, the entities (groups of atoms), which participate in conformational changes in protein, appear to be significantly larger and heavier than those in molecular glasses. No evidence of a small (∼1 cm(-1)) spectral shift tier of the spectral diffusion dynamics has been observed. Therefore, our data most likely reflect the true barrier distributions of the intact protein and not those related to the interface or surrounding host. Possible applications of the barrier distributions as well as the assignments of low-energy states of CP29 and LHCII are discussed in light of the above results.
DEFF Research Database (Denmark)
Colding, H; Møller, S; Bentzon, M W
1983-01-01
Ampicillin and gentamicin were administered continuously intravenously to 88 newborn infants using individually calculated dosages. For infants with a mean value of plasma clearance of the antibiotics, it was calculated that the serum ampicillin and gentamicin concentrations would be between 35-5...
Shi, Mingren; Renton, Michael
2011-10-01
Computational simulation models can provide a way of understanding and predicting insect population dynamics and evolution of resistance, but the usefulness of such models depends on generating or estimating the values of key parameters. In this paper, we describe four numerical algorithms generating or estimating key parameters for simulating four different processes within such models. First, we describe a novel method to generate an offspring genotype table for one- or two-locus genetic models for simulating evolution of resistance, and how this method can be extended to create offspring genotype tables for models with more than two loci. Second, we describe how we use a generalized inverse matrix to find a least-squares solution to an over-determined linear system for estimation of parameters in probit models of kill rates. This algorithm can also be used for the estimation of parameters of Freundlich adsorption isotherms. Third, we describe a simple algorithm to randomly select initial frequencies of genotypes either without any special constraints or with some pre-selected frequencies. Also we give a simple method to calculate the "stable" Hardy-Weinberg equilibrium proportions that would result from these initial frequencies. Fourth we describe how the problem of estimating the intrinsic rate of natural increase of a population can be converted to a root-finding problem and how the bisection algorithm can then be used to find the rate. We implemented all these algorithms using MATLAB and Python code; the key statements in both codes consist of only a few commands and are given in the appendices. The results of numerical experiments are also provided to demonstrate that our algorithms are valid and efficient. Copyright © 2011 Elsevier Inc. All rights reserved.
Noé, Laurent
2017-01-01
Spaced seeds, also named gapped q-grams, gapped k-mers, spaced q-grams, have been proven to be more sensitive than contiguous seeds (contiguous q-grams, contiguous k-mers) in nucleic and amino-acid sequences analysis. Initially proposed to detect sequence similarities and to anchor sequence alignments, spaced seeds have more recently been applied in several alignment-free related methods. Unfortunately, spaced seeds need to be initially designed. This task is known to be time-consuming due to the number of spaced seed candidates. Moreover, it can be altered by a set of arbitrary chosen parameters from the probabilistic alignment models used. In this general context, Dominant seeds have been introduced by Mak and Benson (Bioinformatics 25:302-308, 2009) on the Bernoulli model, in order to reduce the number of spaced seed candidates that are further processed in a parameter-free calculation of the sensitivity. We expand the scope of work of Mak and Benson on single and multiple seeds by considering the Hit Integration model of Chung and Park (BMC Bioinform 11:31, 2010), demonstrate that the same dominance definition can be applied, and that a parameter-free study can be performed without any significant additional cost. We also consider two new discrete models, namely the Heaviside and the Dirac models, where lossless seeds can be integrated. From a theoretical standpoint, we establish a generic framework on all the proposed models, by applying a counting semi-ring to quickly compute large polynomial coefficients needed by the dominance filter. From a practical standpoint, we confirm that dominant seeds reduce the set of, either single seeds to thoroughly analyse, or multiple seeds to store. Moreover, in http://bioinfo.cristal.univ-lille.fr/yass/iedera_dominance, we provide a full list of spaced seeds computed on the four aforementioned models, with one (continuous) parameter left free for each model, and with several (discrete) alignment lengths.
Guerra, Nelson Pérez
2017-01-01
A laboratory experiment in which students study the kinetics of the Viscozyme-L-catalyzed hydrolysis of cellulose and starch comparatively was designed for an upper-division biochemistry laboratory. The main objective of this experiment was to provide an opportunity to perform enhanced enzyme kinetics data analysis using appropriate informatics…
Directory of Open Access Journals (Sweden)
Mariya G. Ganchenkova
2015-12-01
Full Text Available Point defects play a key role in many microelectronics technologies. Knowledge of the properties of point defects and characteristics of their behavior during ion-beam synthesis of microstructures for use in silicon devices allows one to optimize the conditions of their production, improve their quality and the electronic properties. In this situation, of valuable help in studying the properties of point defects is numerical modeling, especially with the use of quantum mechanical methods based on density functional theory approach. The paper describes a systematic study of the effect of various quantum–mechanical simulation approximations on the calculated energy parameters of defects as applied to simple point defects in silicon. We demonstrate that the choice of the form of the exchange–correlation functional has the strongest effect on the predicted defect formation energy, whereas the variation of the other considered approximations is of secondary importance for simulation predictions.
Energy Technology Data Exchange (ETDEWEB)
Prat, O. [Max Planck Institute fuer Eisenforschung GmbH, Max Planck Strasse 1, 40237 Duesseldorf (Germany)] [Universidad de Concepcion, Departamento de Ingenieria de Materiales, Edmundo Larenas 270, Concepcion (Chile); Garcia, J., E-mail: jose.garcia@helmholtz-berlin.de [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Rojas, D. [Max Planck Institute fuer Eisenforschung GmbH, Max Planck Strasse 1, 40237 Duesseldorf (Germany); Carrasco, C. [Universidad de Concepcion, Departamento de Ingenieria de Materiales, Edmundo Larenas 270, Concepcion (Chile); Inden, G. [Max Planck Institute fuer Eisenforschung GmbH, Max Planck Strasse 1, 40237 Duesseldorf (Germany)
2010-10-15
The growth kinetics of Laves phase precipitates (type Fe{sub 2}W) in the early stage of creep (650 deg. C for 10,000 h) in two 12% Cr ferrite-martensitic steels has been investigated. In one alloy the Laves phase formed on tempering, while in the second alloy the Laves phase precipitated during creep. Kinetic simulations were performed using the software DICTRA. The particle size of the Laves phase was measured on transmission electron microscopy samples. The equilibrium phase fraction of the Laves phase was reached in the first thousand hours. Simulations of particle growth showed good agreement with the experimental results. Competitive growth between M{sub 23}C{sub 6} and the Laves phase showed that M{sub 23}C{sub 6} carbides reached their equilibrium after 12 days, whereas the Laves phase reached equilibrium after 3 months. Simulations of the influence of the interfacial energy and addition of Co, Cu and Si on Laves phase precipitation are presented.
Singla, Mallika; Rasmussen, Morten Lund; Hashemi, Hamid; Wu, Hao; Glarborg, Peter; Pelucchi, Matteo; Faravelli, Tiziano; Marshall, Paul
2018-01-24
Limitations in current hot gas cleaning methods for chlorine species from biomass gasification may be a challenge for end use such as gas turbines, engines, and fuel cells, all requiring very low levels of chlorine. During devolatilization of biomass, chlorine is released partly as methyl chloride. In the present work, the thermal conversion of CH 3 Cl under gasification conditions was investigated. A detailed chemical kinetic model for pyrolysis and oxidation of methyl chloride was developed and validated against selected experimental data from the literature. Key reactions of CH 2 Cl with O 2 and C 2 H 4 for which data are scarce were studied by ab initio methods. The model was used to analyze the fate of methyl chloride in gasification processes. The results indicate that CH 3 Cl emissions will be negligible for most gasification technologies, but could be a concern for fluidized bed gasifiers, in particular in low-temperature gasification. The present work illustrates how ab initio theory and chemical kinetic modeling can help to resolve emission issues for thermal processes in industrial scale.
Rasmussen, Troels Hels; Wang, Yang Min; Kjærgaard, Thomas; Kristensen, Kasper
2016-05-01
We augment the recently introduced same number of optimized parameters (SNOOP) scheme [K. Kristensen et al., J. Chem. Phys. 142, 114116 (2015)] for calculating interaction energies of molecular dimers with an F12 correction and generalize the method to enable the determination of interaction energies of general molecular clusters. The SNOOP, uncorrected (UC), and counterpoise (CP) schemes with/without an F12 correction are compared for the S22 test set of Jurečka et al. [Phys. Chem. Chem. Phys. 8, 1985 (2006)]—which consists of 22 molecular dimers of biological importance—and for water and methane molecular clusters. The calculations have been performed using the Resolution of the Identity second-order Møller-Plesset perturbation theory method. We conclude from the results that the SNOOP scheme generally yields interaction energies closer to the complete basis set limit value than the UC and CP approaches, regardless of whether the F12 correction is applied or not. Specifically, using the SNOOP scheme with an F12 correction yields the computationally most efficient way of achieving accurate results at low basis set levels. These conclusions hold both for molecular dimers and more general molecular clusters.
Feshin, V. P.; Feshina, E. V.
2012-03-01
The results of ab initio calculations at the RHF/6-31G(d) and MP2/6-31G(d) levels of two stable structures of the 4-(trichlorgermyl)butan-2-one molecule with total optimization of their geometry have been represented. The structure with pentacoordinated Ge atom is energetically more advantageous as compared with that with tetracoordinated one. Using these results, the 35Cl nuclear quadrupole resonance (NQR) frequencies and asymmetry parameters of the electric field gradient (EFG) at the 35Cl nuclei in molecule with pentacoordinated Ge atom have been assessed, the frequencies satisfactorily agreeing with experimental data. Calculations at the RHF/6-31G(d) level have been performed also at various Ge⋯O distances. It has been demonstrated that convergence of the Ge and O coordination centers leads to the increase of positive charge at the Ge coordination center and of negative charge at the O coordination center, at that, electron density from the Ge atom shifts mainly to the axial Cl atom and from the C atom of carbonyl group - to its O atom. The electron density transfer from the O to Ge atom does not occur.
Directory of Open Access Journals (Sweden)
KHARKHARDIN Anatoly Nikolaevich
2016-08-01
Full Text Available Fiber reinforcement is the process of introduction of fibers of different origins into binding system to enhance strength, stress-strain behavior of products and structures. Maximal effect of reinforcing process is possible when optimal parameters (length and consumption of fibre are determined. Moreover one need to consider particle-size composition and hardening process of binding system. In this paper the critical length of natural and sinthesized fibres as well as minimally required content in cellular systems is calculated with the mathematical apparatus of structural topology. As an example the foam concrete based on cement-free nanostructured binder with basalt fibre and microreinforcing constructional polymeric fibre is studied. Fiber diameter, refined with microstructure analysis, accomplished by SEM-microscopy and experimentally determined packing density in loose and compact state are applied as input parameters. Measurement of the fibre topological characteristics with acceptable is accomplished according to material porosity and pore size. So the minimal effective fibre length taking into account homogeneous distribution in bulk of composite matrix is less of 1 mm; minimal fibre consumption is 0,2–0,5 (by wt. %. Irrational optimization leads to unreasonable cost growth of final materials as well as formation of balling inclusions that negatively affects on final performance of composite.
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Shane Stimpson
2017-09-01
Full Text Available An essential component of the neutron transport solver is the resonance self-shielding calculation used to determine equivalence cross sections. The neutron transport code, MPACT, is currently using the subgroup self-shielding method, in which the method of characteristics (MOC is used to solve purely absorbing fixed-source problems. Recent efforts incorporating multigroup kernels to the MOC solvers in MPACT have reduced runtime by roughly 2×. Applying the same concepts for self-shielding and developing a novel lumped parameter approach to MOC, substantial improvements have also been made to the self-shielding computational efficiency without sacrificing any accuracy. These new multigroup and lumped parameter capabilities have been demonstrated on two test cases: (1 a single lattice with quarter symmetry known as VERA (Virtual Environment for Reactor Applications Progression Problem 2a and (2 a two-dimensional quarter-core slice known as Problem 5a-2D. From these cases, self-shielding computational time was reduced by roughly 3–4×, with a corresponding 15–20% increase in overall memory burden. An azimuthal angle sensitivity study also shows that only half as many angles are needed, yielding an additional speedup of 2×. In total, the improvements yield roughly a 7–8× speedup. Given these performance benefits, these approaches have been adopted as the default in MPACT.
Navarro, F; Harouna, S; Calvo, M; Pérez, M D; Sánchez, L
2015-07-01
Lactoferrin is a protein with important biological functions that can be obtained from milk and by-products derived from the dairy industry, such as whey. Although bovine lactoferrin has been extensively studied, ovine lactoferrin is not quite as well known. In the present study, the effect of several heat treatments in 3 different media, over a temperature range from 66 to 75°C, has been studied on lactoferrin isolated from sheep milk. Denaturation of lactoferrin was determined by measuring its immunoreactivity with specific polyclonal antibodies. Kinetic and thermodynamic parameters obtained indicate that lactoferrin denatures by heat more rapidly in whey than in phosphate buffer or milk. The value of activation energy found for the denaturation process of lactoferrin when treated in whey is higher (390kJ/mol) than that obtained in milk (194kJ/mol) or phosphate buffer (179kJ/mol). This indicates that a great amount of energy is necessary to start denaturation of ovine lactoferrin, probably due to the interaction of this protein with other whey proteins. The changes in the hydrophobicity of lactoferrin after heat treatments were determined by fluorescence measurement using acrylamide. The decrease in the hydrophobicity constant was very small for the treatments from 66 to 75°C, up to 20min, which indicates that lactoferrin conformation did not experienced a great change. The results obtained in this study permit the prediction of behavior of ovine lactoferrin under several heat treatments and show that high-temperature, short-time pasteurization (72°C, 15 s) does not cause loss of its immunoreactivity and, consequently, would not affect its conformation and biological activity. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
DEFF Research Database (Denmark)
Dahl Steffensen, Karina
2011-01-01
Background: Although CA125 kinetic profiles may be related with relapse risk in ovarian cancer patients treated with chemotherapy, no reliable kinetic parameters have been reported. Mathematical modeling may help describe CA125 decline dynamically and determine parameters predictive of relapse...... constant (BETA); CA 125 tumor production (KIN); tumor decay rate constant (KOUT) and treatment indirect effect (Emax relationships with A and A50) “d[CA125]/dt=(KIN* exp [BETA*t]) * (1 - [A/{A+A50}]) – KOUT * (CA125)” where t is time. The predictive values of KIN; KOUT; BETA and A50 estimated during...... treatment arms. Using multivariate analysis adjusted on treatment arms, 4 independent predictive factors of PFS remained significant: BETA (HR=1.35, pmathematical equations describing CA125...
DEFF Research Database (Denmark)
Singla, Mallika; Rasmussen, Morten Lund; Hashemi, Hamid
2018-01-01
Limitations in current hot gas cleaning methods for chlorine species from biomass gasification may be a challenge for end use such as gas turbines, engines, and fuel cells, all requiring very low levels of chlorine. During devolatilization of biomass, chlorine is released partly as methyl chloride....... In the present work, the thermal conversion of CH3Cl under gasification conditions was investigated. A detailed chemical kinetic model for pyrolysis and oxidation of methyl chloride was developed and validated against selected experimental data from the literature. Key reactions of CH2Cl with O2 and C2H4...... for which data are scarce were studied by ab initio methods. The model was used to analyze the fate of methyl chloride in gasification processes. The results indicate that CH3Cl emissions will be negligible for most gasification technologies, but could be a concern for fluidized bed gasifiers, in particular...
Vardi-Kilshtain, Alexandra; Azuri, Asaf; Major, Dan Thomas
2012-02-05
A convenient approach to compute kinetic isotope effects (KIEs) in condensed phase chemical reactions is via path integrals (PIs). Usually, the primitive approximation is used in PI simulations, although such quantum simulations are computationally demanding. The efficiency of PI simulations may be greatly improved, if higher-order Trotter factorizations of the density matrix operator are used. In this study, we use a higher-order PI method, in conjunction with mass-perturbation, to compute heavy-atom KIE in the decarboxylation of orotic acid in explicit sulfolane solvent. The results are in good agreement with experiment and show that the mass-perturbation higher-order Trotter factorization provides a practical approach for computing condensed phase heavy-atom KIE. Copyright © 2011 Wiley Periodicals, Inc.
Kusic, Hrvoje; Juretic, Daria; Koprivanac, Natalija; Marin, Vedrana; Božić, Ana Lončarić
2011-01-30
Three photooxidation processes, UV/H(2)O(2), UV/S(2)O(8)(2-) and UV/O(3) were applied to the treatment of model wastewater containing non-biodegradable organic pollutant, azo dye Acid Orange 7 (AO7). Dye degradation was monitored using UV/VIS and total organic carbon (TOC) analysis, determining decolorization, the degradation/formation of naphthalene and benzene structured AO7 by-products, and the mineralization of model wastewater. The water quality during the treatment was evaluated on the bases of ecological parameters: chemical (COD) and biochemical (BOD(5)) oxygen demand and toxicity on Vibrio fischeri determining the EC(50) value. The main goals of the study were to develop an appropriate mathematic model (MM) predicting the behavior of the systems under investigation, and to evaluate the toxicity and biodegradability of the model wastewater during treatments. MM developed showed a high accuracy in predicting the degradation of AO7 when considering the following observed parameters: decolorization, formation/degradation of by-products and mineralization. Good agreement of the data predicted and the empirically obtained was confirmed by calculated standard deviations. The biodegradability of model wastewater was significantly improved by three processes after mineralizing a half of the initially present organic content. The toxicity AO7 model wastewater was decreased as well. The differences in monitored ecological parameters during the treatment indicated the formation of different by-products of dye degradation regarding the oxidant type applied. Copyright © 2010 Elsevier B.V. All rights reserved.
Zhang, Hui; Zhang, Xin; Truhlar, Donald G; Xu, Xuefei
2017-11-30
The reaction between H and benzene is a prototype for reactions of radicals with aromatic hydrocarbons. Here we report calculations of the reaction rate constants and the branching ratios of the two channels of the reaction (H addition and H abstraction) over a wide temperature and pressure range. Our calculations, obtained with an accurate potential energy surface, are based on variational transition-state theory for the high-pressure limit of the addition reaction and for the abstraction reaction and on system-specific quantum Rice-Ramsperger-Kassel theory calibrated by variational transition-state theory for pressure effects on the addition reaction. The latter is a very convenient way to include variational effects, corner-cutting tunneling, and anharmonicity in falloff calculations. Our results are in very good agreement with the limited experimental data and show the importance of including pressure effects in the temperature interval where the mechanism changes from addition to abstraction. We found a negative temperature effect of the total reaction rate constants at 1 atm pressure in the temperature region where experimental data are missing and accurate theoretical data were previously missing as well. We also calculated the H + C 6 H 6 /C 6 D 6 and D + C 6 H 6 /C 6 D 6 kinetic isotope effects, and we compared our H + C 6 H 6 results to previous theoretical data for H + toluene. We report a very novel nonmonotonic dependence of the kinetic isotope effect on temperature. A particularly striking effect is the prediction of a negative temperature dependence of the total rate constant over 300-500 K wide temperature ranges, depending on the pressure but generally in the range from 600 to 1700 K, which includes the temperature range of ignition in gasoline engines, which is important because aromatics are important components of common fuels.
Energy Technology Data Exchange (ETDEWEB)
London, R.E.; Avitabile, J.
1978-11-08
/sup 13/C NMR relaxation parameters, T/sub 1/, T/sub 2/, and NOE, have been calculated based on a model assuming internal rotational diffusion subject to boundary conditions limiting the range of motion. Numerical results are presented as a function of diffusion coefficients D/sub 0/ and D/sub i/ and angle ..beta.. defined as in the free internal rotation calculation, as well as 2theta, the allowed range of motion. Relaxation times vary from values expected in the absence of internal motion to values slightly below those calculated using the free internal rotation model as the range is increased from 0 to 360/sup 0/. The discrepancy in the latter comparison arises from the boundary condition preventing diffusion from 180/sup +/ to 180/sup -/. Changes in T/sub 2/ are typically monotonic or nearly monotonic as a function of theta; however, changes in T/sub 1/ and NOE values are markedly nonmonotonic for D/sub 0/ approx. < 10/sup 6/ s/sup -1/ and for certain values of D/sub i/. Criteria for the applicability of the present calculations to the analysis of /sup 13/C NMR relaxation data obtained in studies of macromolecules undergoing restricted internal motion have been suggested. The results have been generalized to the case of multiple internal rotations, specifically for the problem of one free and one restricted diffusional process. In general, two types of rotation are not commutative. This model has been applied to relaxation data recently obtained for the methionine methyl resonances of specifically /sup 13/C-labeled dihydrofolate reductase obtained from S. faecium. The results indicate that the data can be readily explained by assuming rapid free internal diffusion about the S--CH/sub 3/ bond and restricted internal diffusion about the CH/sub 2/--S bond of methionine, such that for the broadest resonances the motional range is restricted to approx. 90/sup 0/ and for the sharpest resonances the range is >180/sup 0/. Restriction of the motion allows a
Directory of Open Access Journals (Sweden)
Dániel Radva
2011-01-01
Full Text Available The activity of enzymes after the immobilization by weak interactions such as adsorption or adsorption followed by a cross-linking reaction can change easily not only during further application but during the activity measured via desorption and/or inactivation of enzymes. The changes in activity could be a consequence of the interactions between the enzyme and support. In this work a quick and efficient method is developed that permits studying of the strength and properties of the forces between the enzymes and support by examining the kinetics of desorption and/or inactivation. Applying this new cyclic kinetic desorption method, the effect of reaction parameters on immobilization could also be studied. The efficiency of this method was tested for optimizing the parameters for immobilization of β-glucosidase on Amberlite IRA 900 anion exchange resin by an adsorption followed by a cross-linking with glutaraldehyde to form potential preparation for food industry. The following parameters were chosen: concentration (0.10 M of the buffer (sodium acetate, pH=5.5 and the ratio of carrier to enzyme (10:1 for the adsorption step, then the time of treatment (1 min and concentration (0.25, by mass per volume of glutaraldehyde for the cross-linking by using the kinetic desorption method. The activity of this preparation was 57 μmol/(min·g in respect of dry resin. It was established that the effect of different parameters on this enzyme immobilization could be characterized by the new cyclic kinetic desorption method in a quick and efficient way; furthermore, it permitted separate testing of the effect of parameters on the adsorption and cross-linking processes.
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Dilip K. Rajak
2017-12-01
Full Text Available Dry grinding of Class F fly ash (FA was carried out using the planetary ball mill to obtain mechanically activated nanostructured FA particles. The resulting FA powders were characterized for (i particle size: dynamic light scattering and sieve analyzer, (ii specific surface area: BET-analyzer, (iii structure: X-ray diffractometer, (iv chemical composition: field emission scanning electron microscope with the electron diffraction spectrum analyzer and x-ray fluorescence analyzer, and (v aggregation and shape of the particles: Fourier-transformed infra-red spectrometer and scanning electron microscope. A significant enhancement in surface and bulk properties of milled FA was obtained over fresh FA. The breakage parameters (i.e., the specific rate of breakage and primary breakage distribution function of FA were determined by the direct experimental method using the narrowly-sized fraction of FA over the short grinding period under identical milling environment. A relatively simple back-calculation method was employed to determine above breakage parameters of FA also using time-variant milling data that were obtained after the grinding of distributed-sized FA feed. The parameters obtained from the direct experimental and back-calculation method yielded comparative milling simulation results with the acceptable accuracy. Keywords: Planetary ball mill, Fly ash, Population balance model, Direct- and back-calculation method, Breakage parameters, Parameter optimization
Tesmar, Aleksandra; Wyrzykowski, Dariusz; Muñoz, Eva; Pilarski, Bogusław; Pranczk, Joanna; Jacewicz, Dagmara; Chmurzyński, Lech
2017-04-01
The influence of the different side chain residues on the thermodynamic and kinetic parameters for complexation reactions of the Co 2 + and Ni 2 + ions has been investigated by using the isothermal titration calorimetry (ITC) technique supported by potentiometric titration data. The study was concerned with the 2 common tripodal aminocarboxylate ligands, namely, nitrilotriacetic acid and N-(2-hydroxyethyl) iminodiacetic acid. Calorimetric measurements (ITC) were run in the 2-(N-morpholino)ethanesulfonic acid hydrate (2-(N-morpholino) ethanesulfonic acid), piperazine-N,N'-bis(2-ethanesulfonic acid), and dimethylarsenic acid buffers (0.1 mol L -1 , pH 6) at 298.15 K. The quantification of the metal-buffer interactions and their incorporation into the ITC data analysis enabled to obtain the pH-independent and buffer-independent thermodynamic parameters (K, ΔG, ΔH, and ΔS) for the reactions under study. Furthermore, the kinITC method was applied to obtain kinetic information on complexation reactions from the ITC data. Correlations, based on kinetic and thermodynamic data, between the kinetics of formation of Co 2 + and Ni 2 + complexes and their thermodynamic stabilities are discussed. Copyright © 2016 John Wiley & Sons, Ltd.
Bertoldi, Dalía S.; Ramos, Susana B.; Guillermet, Armando Fernández
2017-08-01
We present a theoretical analysis of the equation of state (EOS) of metals using a quasi-harmonic Einstein model with a dimensionless cohesive energy versus distance function (F(z)) involving the Wigner-Seitz radius and a material-dependent scaling length, as suggested in classical works by Rose, Ferrante, Smith and collaborators. Using this model, and ;universal; values for the function and its first and second derivatives at the equilibrium distance (z=0), three general interrelations between EOS parameters and the cohesive energy are obtained. The first correlation involves the bulk modulus, and the second, the thermal expansion coefficient. In order to test these results an extensive database is developed, which involves available experimental data, and results of current ab initio density-functional-theory calculations using the VASP code. In particular, the 0 K values for volume, bulk modulus, its pressure derivative, and the cohesive energy of 27 elements belonging to the first (Sc, Ti, V, Cr, Fe, Co, Ni, Cu, Zn), second (Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd) and third (Hf, Ta, W, Re, Os, Ir, Pt, Au) transition row of the Periodic Table are calculated ab initio and used to test the present results. The third correlation obtained, allows an evaluation of the third derivative of F(z) at z=0 for the current elements. With this new information, a discussion is presented of the possibility of finding a ;universal; F(z) versus z function able to account accurately for the pressure derivative of the bulk modulus of the transition elements.
Hsieh, Po-Fan; Wang, Yu-De; Huang, Chi-Ping; Wu, Hsi-Chin; Yang, Che-Rei; Chen, Guang-Heng; Chang, Chao-Hsiang
2016-07-01
We proposed a mathematical formula to calculate contact surface area between a tumor and renal parenchyma. We examined the applicability of using contact surface area to predict renal function after partial nephrectomy. We performed this retrospective study in patients who underwent partial nephrectomy between January 2012 and December 2014. Based on abdominopelvic computerized tomography or magnetic resonance imaging, we calculated the contact surface area using the formula (2*π*radius*depth) developed by integral calculus. We then evaluated the correlation between contact surface area and perioperative parameters, and compared contact surface area and R.E.N.A.L. (Radius/Exophytic/endophytic/Nearness to collecting system/Anterior/Location) score in predicting a reduction in renal function. Overall 35, 26 and 45 patients underwent partial nephrectomy with open, laparoscopic and robotic approaches, respectively. Mean ± SD contact surface area was 30.7±26.1 cm(2) and median (IQR) R.E.N.A.L. score was 7 (2.25). Spearman correlation analysis showed that contact surface area was significantly associated with estimated blood loss (p=0.04), operative time (p=0.04) and percent change in estimated glomerular filtration rate (p filtration rate (p filtration rate compared to R.E.N.A.L. score (AUC 0.86 vs 0.69). Using this simple mathematical method, contact surface area was associated with surgical outcomes. Compared to R.E.N.A.L. score, contact surface area was a better predictor of functional change after partial nephrectomy. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.
Morozova, E.; Kulikova, V.; Yashin, D.; Anufrieva, N.; Anisimova, N.; Revtovich, S.; Kotlov, M.; Belyi, Y.; Pokrovsky, V.; Demidkina, T.
2013-01-01
The steady-state kinetic parameters of pyridoxal 5?-phosphate-dependent recombinant methionine ? -lyase from three pathogenic bacteria, Clostridium tetani, Clostridium sporogenes, and Porphyromonas gingivalis, were determined in ?- and ?-elimination reactions. The enzyme from C. sporogenes is characterized by the highest catalytic efficiency in the ?-elimination reaction of L-methionine. It was demonstrated that the enzyme from these three sources exists as a tetramer. The N-terminal poly-his...
Saturno, J; Blanco, L; Salas, M; Esteban, J A
1995-12-29
Amino acids Tyr254 and Tyr390 of phi 29 DNA polymerase belong to one of the most conserved regions in eukaryotic-type DNA polymerases. In this paper we report a mutational study of these two residues to address their role in nucleotide selection. This study was carried out by means of a new kinetic analysis that takes advantage of the competition between DNA polymerization and 3'-->5' exonuclease activity to measure the Km values for correct and incorrect nucleotides in steady-state conditions. This method is valid for any 3'-->5' exonuclease-containing DNA polymerase, without any restriction concerning catalytic rates of nucleotide incorporation. The results showed that the discrimination factor achieved by phi 29 DNA polymerase in the nucleotide binding step of DNA polymerization is 2.4 x 10(3), that is, a wrong nucleotide is bound with a 2.4 x 10(3)-fold lower affinity than the correct one. Mutants Y254F, Y390F, and Y390S showed discrimination values of 7.0 x 10(2), > 1.9 x 10(3), and 2.9 x 10(2), respectively. The reduced accuracy of nucleotide binding produced by mutations Y254F and Y390S lead us to propose that phi 29 DNA polymerase residues Tyr254 and Tyr390, highly conserved in eukaryotic-type DNA polymerases, are involved in nucleotide binding selection, thus playing a crucial role in the fidelity of DNA replication. Comparison of the discrimination factors of mutants Y390S and Y390F strongly suggests that the phenyl ring of Tyr390 is directly involved in checking base-pairing correctness of the incoming nucleotide.
Wardak, Mirwais; Schiepers, Christiaan; Dahlbom, Magnus; Cloughesy, Timothy; Chen, Wei; Satyamurthy, Nagichettiar; Czernin, Johannes; Phelps, Michael E.; Huang, Sung-Cheng
2011-01-01
Purpose The primary objective of this study was to investigate if changes in 18F-FLT kinetic parameters, taken at an early stage after start of therapy, could predict overall survival (OS) and progression-free survival (PFS) in patients with recurrent malignant glioma undergoing treatment with bevacizumab and irinotecan. Experimental Design High-grade recurrent brain tumors were investigated in 18 patients (8M, 10F), 26-76 yr. Each had 3 dynamic PET studies: at baseline, and after 2 weeks, and 6 weeks from the start of treatment. 2.0 MBq/kg of 18F-FLT was injected intravenously and dynamic PET images acquired for 1 hr. Factor analysis generated factor images from which blood and tumor uptake curves were derived. A 3-compartment, 2-tissue model was applied to estimate the tumor 18F-FLT kinetic rate constants using a metabolite and partial volume corrected input function. Different combinations of predictor variables were exhaustively searched in a discriminant function to accurately classify patients into their known OS and PFS groups. A leave-one-out cross-validation technique was used to assess the generalizability of the model predictions. Results In this study population, changes in single parameters such as standardized uptake value or influx rate constant did not accurately classify patients into their respective OS groups (Discriminant analysis using changes in 18F-FLT kinetic parameters early during treatment appears to be a powerful method for evaluating the efficacy of therapeutic regimens. PMID:21868765
Gonzalez, Dayana; Mebel, Alexander
2016-03-01
It has been recently shown that Titan provides a unique perspective in our solar system: its atmosphere is comparable to a model of prebiotic Earth's. Provided the organic cationic and anionic molecular species identified by the Cassini spacecraft, this research characterizes reaction pathways for the reactions of methyl derivatives of the cyclopropenyl cation, the methyl cation with methyl- and dimethyl-acetylene, and reactions of resonance structures of protonated acrylonitrile with CH2NH. Isomerization and dissociation reactions involving methyl-cyclopropenyl cations, the perinaphthenyl cation and anion, and cations of pyrimidine and purine precursors of nucleobases will be examined to locate reaction pathways, intermediates, transition states, and products of the reactions. Gaussian '09 software is used for ab initio calculations to map out the PES. Geometry optimizations and vibrational frequency computations are preformed via the double-hybrid density functional B2PLYP-D3. Single-point energies are refined by use of the explicitly-correlated coupled-cluster CCSD(T)-F12 method. Rate constants are calculated using microcanonical RRKM theory, and pressure effects evaluated used the Master Equation approach; these allow for prediction of absolute rate constants and product branching ratios at different pressures and temperatures.
Energy Technology Data Exchange (ETDEWEB)
Aliaga, Maria J.; Caturla, Maria J. [Facultad de Ciencias, Department Fisica Aplicada, Fase II, Universidad de Alicante, 03690, Alicante (Spain); Dopico, Ignacio; Martin-Bragado, Ignacio [IMDEA Materials Institute, C/Eric Kandel 2, 28906, Getafe, Madrid (Spain)
2016-11-15
The influence of surfaces on the evolution of damage of irradiated Fe is studied using object kinetic Monte Carlo with input from molecular dynamics simulations and ab initio calculations. Two effects are analysed: the influence of traps and the initial distribution of damage in the cascade. These simulations show that for a trap concentration of around 100 appm, there are no significant differences between defect concentrations in bulk and thin films. However, the initial distribution of defects plays an important role not only on total defect concentration but also on defect type, for the model used in this study. Damage produced by a 100 keV Fe ion impinging a Fe thin film. Blue (dark) spheres are self-interstitials, red (light) spheres are vacancies. (copyright 2016 The Authors/Employers. Phys. Status Solidi A published by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Wang, Wenji; Zhao, Yi
2012-12-07
Thermal rate constants for the title reaction are calculated by using the quantum instanton approximation within the full dimensional Cartesian coordinates. The results reveal that the quantum effect is remarkable for the reaction at both low and high temperatures, and the obtained rates are in good agreement with experimental measurements at high temperatures. Compared to the harmonic approximation, the torsional anharmonic effect of the internal rotation has a little influence on the rates at low temperatures, however, it enhances the rate by about 20% at 1000 K. In addition, the free energy barriers for the isotopic reactions and the temperature dependence of kinetic isotope effects are also investigated. Generally speaking, for the title reaction, the replacement of OH with OD will reduce the free energy barrier, while substituting D for H (connected to C) will increase the free energy barrier.
Directory of Open Access Journals (Sweden)
R.V. Zaitsev
2016-09-01
Full Text Available Purpose. To ensure maximum production of electric power by photovoltaic vacilities, in addition to using highly efficient photovoltaic modules equipped with solar radiation concentrators must use a highly effective power take-off system. This paper is inscribed to solving the problem of a highly efficient and economic power take-off system development. Methodology. To solving the problem, we implemented three stages. On the first stage examines the dependence of electrical power from the intensity of the incident solar radiation. Based on this, the second stage is calculated the DC-DC converter resonant circuit and its working parameters, and developed circuit diagram of DC-DC converter. On the third stage, we carry out an analysis of power take-off system with step up DC-DC converter working. Results. In this paper, we carry out the analysis of working efficiency for photovoltaic facility power take-off system with step-up boost converter. The result of such analysis show that the efficiency of such system in a wide range of photovoltaic energy module illumination power is at 0.92, whereas the efficiency of classic power take-off systems does not exceed 0.70. Achieved results allow designing a circuit scheme of a controlled bridge resonant step-up converter with digital control. Proposed scheme will ensure reliable operation, fast and accurate location point of maximum power and conversion efficiency up to 0.96. Originality. Novelty of proposed power take-off system solution constitute in implementation of circuit with DC-DC converters, which as it shown by results of carrying out modeling is the most effective. Practical value. Practical implementation of proposed power take-off system design will allow reducing losses in connective wires and increasing the efficiency of such a system up to 92.5% in wide range of photovoltaic energy modules illumination.
Ismail, Ahmad Muhaimin; Mohamad, Mohd Saberi; Abdul Majid, Hairudin; Abas, Khairul Hamimah; Deris, Safaai; Zaki, Nazar; Mohd Hashim, Siti Zaiton; Ibrahim, Zuwairie; Remli, Muhammad Akmal
2017-09-23
Mathematical modelling is fundamental to understand the dynamic behavior and regulation of the biochemical metabolisms and pathways that are found in biological systems. Pathways are used to describe complex processes that involve many parameters. It is important to have an accurate and complete set of parameters that describe the characteristics of a given model. However, measuring these parameters is typically difficult and even impossible in some cases. Furthermore, the experimental data are often incomplete and also suffer from experimental noise. These shortcomings make it challenging to identify the best-fit parameters that can represent the actual biological processes involved in biological systems. Computational approaches are required to estimate these parameters. The estimation is converted into multimodal optimization problems that require a global optimization algorithm that can avoid local solutions. These local solutions can lead to a bad fit when calibrating with a model. Although the model itself can potentially match a set of experimental data, a high-performance estimation algorithm is required to improve the quality of the solutions. This paper describes an improved hybrid of particle swarm optimization and the gravitational search algorithm (IPSOGSA) to improve the efficiency of a global optimum (the best set of kinetic parameter values) search. The findings suggest that the proposed algorithm is capable of narrowing down the search space by exploiting the feasible solution areas. Hence, the proposed algorithm is able to achieve a near-optimal set of parameters at a fast convergence speed. The proposed algorithm was tested and evaluated based on two aspartate pathways that were obtained from the BioModels Database. The results show that the proposed algorithm outperformed other standard optimization algorithms in terms of accuracy and near-optimal kinetic parameter estimation. Nevertheless, the proposed algorithm is only expected to work well in
Malamis, S; Katsou, E
2013-05-15
Adsorption and ion exchange can be effectively employed for the treatment of metal-contaminated wastewater streams. The use of low-cost materials as sorbents increases the competitive advantage of the process. Natural and modified minerals have been extensively employed for the removal of nickel and zinc from water and wastewater. This work critically reviews existing knowledge and research on the uptake of nickel and zinc by natural and modified zeolite, bentonite and vermiculite. It focuses on the examination of different parameters affecting the process, system kinetics and equilibrium conditions. The process parameters under investigation are the initial metal concentration, ionic strength, solution pH, adsorbent type, grain size and concentration, temperature, agitation speed, presence of competing ions in the solution and type of adsorbate. The system's performance is evaluated with respect to the overall metal removal and the adsorption capacity. Furthermore, research works comparing the process kinetics with existing reaction kinetic and diffusion models are reviewed as well as works examining the performance of isotherm models against the experimental equilibrium data. Copyright © 2013. Published by Elsevier B.V.
Directory of Open Access Journals (Sweden)
M. KHODABANDEH
2011-03-01
Full Text Available A kinetic model for Cupriavidus necator in batch culture using glucose, fructose and molasses as carbon sources was obtained. The experimental data was also fitted with the modified logistic equation that can provide adequate description for PHB synthesized by C. necator. The Lineweaver-Burk plot defined biokinetic coefficients which were described by a simplified Monod’s rate model. The specific growth rates, μmax and the Monod constants, Ks, for various substrates such as glucose, fructose and molasses were 0.18, 1.25, 0.42 h-1 and 107.53, 30.342 and 188.16 g/l, respectively. The kinetic constants were evaluated on the basis of non-linear regression solved using MATLAB soft¬ware. Good agreement was found between the experimental and the predicted values, which indicated that the model with differential equations would describe fermentation process for the PHB formation.
Energy Technology Data Exchange (ETDEWEB)
Naumov, V.A.; Gavrilov, L.I.
1979-11-01
In a continuing study of the kinetics of the Sabatier reaction, Soviet researchers applied a thermokinetic method to determine the activation energy and the order of the reaction rate with respect to CO/sub 2/ and H/sub 2/ in the hydrogenation of CO/sub 2/ to CH/sub 4/ and H/sub 2/O over a nickel catalyst. The results agree with earlier conclusions that with large H/sub 2//CO/sub 2/ ratios and temperatures less than 520/sup 0/F (270/sup 0/C), the kinetics of the reaction follow an equation of the first order with respect to CO/sub 2/. The values of the activation energy obtained by three kinetic methods agree reasonably well: thermokinetic, 100.9 Btu (106.4 kj)/mol; flow-through/circulating, 107.2 Btu (113.1 kj)/mol; flow-though differential, 102.1 Btu (107.7 kj)/mol.
Determination of Kinetic Parameters for Methane Oxidation over Pt/γ-Al2O3 in a Fixed-Bed Reactor
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Vita Wonoputri
2013-07-01
Full Text Available This paper describes akinetic study for the determination of the kinetic parameters of lean methane emission oxidation over Pt/γ-Al2O3 in a dedicated laboratory scale fixed bed reactor. A model ofthemechanistic reaction kinetic parameters has been developed. The reaction rate model was determined using therate-limiting step method, which was integrated and optimized to find the most suitable model and parameters. Based on this study, the Langmuir-Hinshelwood reaction rate model with the best correlationis the one where the rate-limiting step is thesurface reaction between methane and one adsorbed oxygen atom. The pre-exponential factor and activation energy were 9.19 x 105 and 92.04 kJ/mol, while the methane and oxygen adsorption entropy and enthalpy were –17.46 J/mol.K, –2739.36 J/mol,–16.34 J/mol.K, and –6157.09 J/mol, respectively.
Owhondah, Raymond O; Walker, Mark; Ma, Lin; Nimmo, Bill; Ingham, Derek B; Poggio, Davide; Pourkashanian, Mohamed
2016-06-01
Biochemical reactions occurring during anaerobic digestion have been modelled using reaction kinetic equations such as first-order, Contois and Monod which are then combined to form mechanistic models. This work considers models which include between one and three biochemical reactions to investigate if the choice of the reaction rate equation, complexity of the model structure as well as the inclusion of inhibition plays a key role in the ability of the model to describe the methane production from the semi-continuous anaerobic digestion of green waste (GW) and food waste (FW). A parameter estimation method was used to investigate the most important phenomena influencing the biogas production process. Experimental data were used to numerically estimate the model parameters and the quality of fit was quantified. Results obtained reveal that the model structure (i.e. number of reactions, inhibition) has a much stronger influence on the quality of fit compared with the choice of kinetic rate equations. In the case of GW there was only a marginal improvement when moving from a one to two reaction model, and none with inclusion of inhibition or three reactions. However, the behaviour of FW digestion was more complex and required either a two or three reaction model with inhibition functions for both ammonia and volatile fatty acids. Parameter values for the best fitting models are given for use by other authors.
Cheng, Tao; Xiao, Hai; Goddard, William A
2017-02-21
A critical step toward the rational design of new catalysts that achieve selective and efficient reduction of CO2 to specific hydrocarbons and oxygenates is to determine the detailed reaction mechanism including kinetics and product selectivity as a function of pH and applied potential for known systems. To accomplish this, we apply ab initio molecular metadynamics simulations (AIMμD) for the water/Cu(100) system with five layers of the explicit solvent under a potential of -0.59 V [reversible hydrogen electrode (RHE)] at pH 7 and compare with experiment. From these free-energy calculations, we determined the kinetics and pathways for major products (ethylene and methane) and minor products (ethanol, glyoxal, glycolaldehyde, ethylene glycol, acetaldehyde, ethane, and methanol). For an applied potential (U) greater than -0.6 V (RHE) ethylene, the major product, is produced via the Eley-Rideal (ER) mechanism using H2O + e- The rate-determining step (RDS) is C-C coupling of two CO, with ΔG‡ = 0.69 eV. For an applied potential less than -0.60 V (RHE), the rate of ethylene formation decreases, mainly due to the loss of CO surface sites, which are replaced by H*. The reappearance of C2H4 along with CH4 at U less than -0.85 V arises from *CHO formation produced via an ER process of H* with nonadsorbed CO (a unique result). This *CHO is the common intermediate for the formation of both CH4 and C2H4 These results suggest that, to obtain hydrocarbon products selectively and efficiency at pH 7, we need to increase the CO concentration by changing the solvent or alloying the surface.
DEFF Research Database (Denmark)
Steffansen, Bente; El-Sayed, F
Previously, we have suggested estrone-1-sulfate (E1S) to be intercalated into the phospholipid membrane 1,2-dipalmitoyl-sn-glycero-3-phospho-choline (DPPC). The overall hypothesis of the present study was that E1S intercalation in the cell membrane of Caco-2 cells may changes the functionality...... of membrane transporters. The aim was therefore to investigate if addition of E1S to the growth medium of Caco-2 cells before but not during the influx study, change the kinetic parameters of transporter-mediated influx of taurine and glutamate by respective TAUT and EAAT transporters. The results show that 4...
Mellado, Maria Candida M; Mena, Jimmy A; Lopes, António; Ramírez, Octavio T; Carrondo, Manuel J T; Palomares, Laura A; Alves, Paula M
2009-11-01
Virus-like particles constitute potentially relevant vaccine candidates. Nevertheless, their behavior in vitro and assembly process needs to be understood in order to improve their yield and quality. In this study we aimed at addressing these issues and for that purpose triple- and double-layered rotavirus-like particles (TLP 2/6/7 and DLP 2/6, respectively) size and zeta potential were measured using dynamic light scattering at different physicochemical conditions, namely pH, ionic strength, and temperature. Both TLP and DLP were stable within a pH range of 3-7 and at 5-25 degrees C. Aggregation occurred at 35-45 degrees C and their disassembly became evident at 65 degrees C. The isoelectric points of TLP and DLP were 3.0 and 3.8, respectively. In vitro kinetics of TLP disassembly was monitored. Ionic strength, temperature, and the chelating agent employed determined disassembly kinetics. Glycerol (10%) stabilized TLP by preventing its disassembly. Disassembled TLP was able to reassemble by dialysis at high calcium conditions. VP7 monomers were added to DLP in the presence of calcium to follow in vitro TLP assembly kinetics; its assembly rate being mostly affected by pH. Finally, DLP and TLP were found to coexist under certain conditions as determined from all reaction products analyzed by capillary electrophoresis. Overall, these results contribute to the design of new strategies for the improvement of TLP yield and quality by reducing the VP7 detachment from TLP. Copyright 2009 Wiley Periodicals, Inc.
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Hreha Pavol
2015-06-01
Full Text Available The paper deals with a study of relations between the measured Ra, Rq, Rz surface roughness parameters, the traverse speed of cutting head v and the vibration parameters, PtP, RMS, vRa, generated during abrasive water jet cutting of the AISI 309 stainless steel. Equations for prediction of the surface roughness parameters were derived according to the vibration parameter and the traverse speed of cutting head. Accuracy of the equations is described according to the Euclidean distances. The results are suitable for an on-line control model simulating abrasive water jet cutting and machining using an accompanying physical phenomenon for the process control which eliminates intervention of the operator.
Song, Minsu; Kim, Jonghyun
2017-07-12
For healthcare and clinical use, ambulatory gait monitoring systems using inertial sensors have been developed to estimate the user gait parameters, such as walking speed, stride time, and stride length. However, to adapt the systems effectively to daily-life activities, they need to be able to classify the gait activities of daily-life to obtain the parameters for each activity. In this study, we propose a simple classification algorithm based on a single inertial sensor for ease of use, which classifies three major gait activities: leveled walk, ramp walk, and stair walk. The classification can be performed with gait parameter estimation simultaneously. The developed system that includes classification and parameter estimation algorithms was evaluated with eight healthy subjects within a gait lab and on an outdoor daily-life walking course. The results showed that the estimated gait parameters were comparable to existing studies (range of walking speed root mean square error (RMSE): 0.059-0.129 m/s), and the classification accuracy was sufficiently high for all three gait activities: 98.5 % for the indoor gait lab experiment and 95.5 % for the outdoor complex daily-life walking course experiment. The proposed system is simple and effective for daily-life gait analysis, including gait activity classification and gait parameter estimation. for each activity.
National Research Council Canada - National Science Library
Anand V. Metre; Kaushik Nath
2015-01-01
...) catalyst was studied. The effects of various physico-chemical parameters such as temperature, PFAD to methanol molar ratio and amount of catalyst on the conversion of biodiesel were investigated...
Garcia-Comas, Maya; Lopez-Puertas, M.; Funke, B.; Bermejo-Pantaleon, D.; Marshall, Benjamin T.; Mertens, Christopher J.; Remsberg, Ellis E.; Mlynczak, Martin G.; Gordley, L. L.; Russell, James M.
2008-01-01
The vast set of near global and continuous atmospheric measurements made by the SABER instrument since 2002, including daytime and nighttime kinetic temperature (T(sub k)) from 20 to 105 km, is available to the scientific community. The temperature is retrieved from SABER measurements of the atmospheric 15 micron CO2 limb emission. This emission separates from local thermodynamic equilibrium (LTE) conditions in the rarefied mesosphere and thermosphere, making it necessary to consider the CO2 vibrational state non-LTE populations in the retrieval algorithm above 70 km. Those populations depend on kinetic parameters describing the rate at which energy exchange between atmospheric molecules take place, but some of these collisional rates are not well known. We consider current uncertainties in the rates of quenching of CO2 (v2 ) by N2 , O2 and O, and the CO2 (v2 ) vibrational-vibrational exchange to estimate their impact on SABER T(sub k) for different atmospheric conditions. The T(sub k) is more sensitive to the uncertainty in the latter two and their effects depend on altitude. The T(sub k) combined systematic error due to non-LTE kinetic parameters does not exceed +/- 1.5 K below 95 km and +/- 4-5 K at 100 km for most latitudes and seasons (except for polar summer) if the Tk profile does not have pronounced vertical structure. The error is +/- 3 K at 80 km, +/- 6 K at 84 km and +/- 18 K at 100 km under the less favourable polar summer conditions. For strong temperature inversion layers, the errors reach +/- 3 K at 82 km and +/- 8 K at 90 km. This particularly affects tide amplitude estimates, with errors of up to +/- 3 K.
Tunali, Sibel; Ozcan, Adnan; Kaynak, Zerrin; Ozcan, A Safa; Akar, Tamer
2007-04-01
In the present study, biosorption of Acid Red 57 (AR57) onto a waste biomass of Phaseolus vulgaris L. was investigated by varying pH, contact time, biosorbent concentration and temperature, to determine the equilibrium, thermodynamic and kinetic parameters. The AR57 biosorption was fast, and equilibrium was attained within 20 min. Biosorption equilibrium data fit the Langmuir isotherm model well with high correlation coefficients. According to Langmuir isotherm model the maximum biosorption capacity of Phaseolus vulgaris L. for AR57 dye was determined as 4.09 x 10(- 4) mol g(- 1) or 215.13 mg g(- 1) at 20 degrees C. The thermodynamic parameters (Gibbs free energy, enthalpy and entropy) for the biosorption of AR57 were indicated that the biosorption was spontaneous and exothermic in nature. The pseudo-second-order kinetic model agrees well with the dynamic behavior of the biosorption of AR57 onto P. vulgaris L., under various temperatures. The removal efficiency of the biomass was also examined in real textile wastewater.
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V.I. Milykh
2016-03-01
Full Text Available The theoretical bases of calculation of electromagnetic quantities and time-phase relationship are presented for the turbo-generators. This is done by numerical calculations of the magnetic field in the software environment package FEMM (Finite Element Method Magnetics. A program which controls calculations and organizes the issuance of the results to a text file is created on the algorithmic language Lua. The program is universal in terms of a turbo-generator models, as well as steady-state modes of their work with a minimum of input data. The exciting current of the rotor and the phase currents of three-phase stator winding in accordance with their initial phase are given for the calculation of the magnetic field. The key function for the analysis of electromagnetic parameters is the calculated angular function of the magnetic flux phase stator winding. The expansion in the harmonic series is carried out and amplitude and initial phase are received for this function. Next, the phase EMF and voltage, phase shifts between all values, active power, electromagnetic torque, the magnetic flux in the gap and other parameters are determined. The presented Lua script is a prototype for a similar calculation software of electric machines of other types.
Jafri, Lena; Khan, Aysha Habib; Azeem, Saba
2013-01-01
To determine the concentration of ionized calcium (iCa) collected in lithium heparin and gel tubes and to correlate the measured iCa with calculated iCa. Anaerobic fasting blood samples were simultaneously collected from healthy laboratory workers in lithium-heparin and gel tubes. iCa, pH, total calcium (CaT), total protein and albumin were measured. Ionized Ca was calculated with albumin and globulin values using an appropriate formula. Mean iCa in gel tubes showed a positive constant bias o...
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Henry Bastidas Mora
2011-09-01
Full Text Available This article presents an analysis of electrical distribution theory for 60Hz-lines operating at low voltage, particularly underground lines and residential indoor installations. Such distribution lines’ behaviour is observed as a function of frequency to consider any advantages regarding the potential use of power transmission lines (PTL for transmitting telecommunication signals. A method for computing the secondary parameters is proposed which has been based on the primary parameters, namely inductance, capacitance, conductance and resistance. The secondary parameters so obtained were characteristic impedance, propagation constant (together with its real value and the attenuation constant. Conductor configurations, insulation materials and gauges commonly used in Colombia were verified for such low-voltage lines. A mathematical model is proposed as a theoretical tool for analysing and predicting characteristic impedance pattern and the attenuations which occur at high frequencies, thereby complementing our group’s previous work. Conclusions are drawn, together with a perspective regarding future work and applications.
Kuo, Chao-Yin; Wu, Chung-Hsin; Wu, Jane-Yii
2008-11-15
This study examined the feasibility of removing direct dyes C.I. Direct Yellow 86 (DY86) and C.I. Direct Red 224 (DR224) from aqueous solutions using carbon nanotubes (CNTs). The effects of dye concentration, CNT dosage, ionic strength and temperature on adsorption of direct dyes by CNTs were also evaluated. Pseudo second-order, intraparticle diffusion and Bangham models were adopted to evaluate experimental data and thereby elucidate the kinetic adsorption process. Additionally, this study used the Langmuir, Freundlich, Dubinin and Radushkevich (D-R) and Temkin isotherms to describe equilibrium adsorption. The adsorption percentage of direct dyes increased as CNTs dosage, NaCl addition and temperature increased. Conversely, the adsorption percentage of direct dyes decreased as dye concentration increased. The pseudo second-order model best represented adsorption kinetics. Based on the regressions of intraparticle diffusion and Bangham models, experimental data suggest that the adsorption of direct dyes onto CNTs involved intraparticle diffusion, but that was not the only rate-controlling step. The equilibrium adsorption of DR86 is best fitted in the Freundlich isotherm and that of DR224 was best fitted in the D-R isotherm. The capacity of CNTs to adsorb DY86 and DR224 was 56.2 and 61.3 mg/g, respectively. For DY86, enthalpy (DeltaH(0)) and entropy (DeltaS(0)) were 13.69 kJ/mol and 139.51 J/mol K, respectively, and those for DR224 were 24.29 kJ/mol and 172.06 J/mol K, respectively. The values of DeltaH(0), DeltaG(0) and E all indicate that the adsorption of direct dyes onto CNTs was a physisorption process.
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Zhukov Ilya S.
2016-01-01
Full Text Available On the basis of obtained analytical estimate of characteristics of hybrid solid-propellant rocket engine verification of earlier developed physical and mathematical model of processes in a hybrid solid-propellant rocket engine for quasi-steady-state flow regime was performed. Comparative analysis of calculated and analytical data indicated satisfactory comparability of simulation results.
Energy Technology Data Exchange (ETDEWEB)
Sotiropoulou, Maria [INRASTES, NCSR ' ' Demokritos' ' , Environmental Radioactivity Laboratory, Athens (Greece); Aristotle University of Thessaloniki, Atomic and Nuclear Physics Laboratory, Thessaloniki (Greece); Florou, Heleny [INRASTES, NCSR ' ' Demokritos' ' , Environmental Radioactivity Laboratory, Athens (Greece); Kitis, Georgios [Aristotle University of Thessaloniki, Atomic and Nuclear Physics Laboratory, Thessaloniki (Greece)
2017-11-15
The substantial complexity in ecosystem-radionuclide interactions is difficult to be represented in terms of radiological doses. Thus, radiological dose assessment tools use typical exposure situations for generalized organisms and ecosystems. In the present study, site-specific data and radioactivity measurements of terrestrial organisms (grass and herbivore mammals) and abiotic components (soil) are provided. The retrieved data are used in combination with the ERICA Assessment Tool for calculation of radiological parameters. The process of radionuclide transfer within ecosystem components is represented using concentration ratios (CRs), while for the calculation of dose rates the dose conversion coefficient (DCC) methodology is applied. Comparative assessments are performed between the generic and assessment-specific radiological parameters and between the resulting dose rates. Significant differences were observed between CRs calculated in this study and those reported in the literature for cesium and thorium, which can easily be explained. On the other hand, CRs calculated for radium are in very good agreement with those reported in the literature. The DCCs exhibited some small differences between the reference and the assessment-specific organism due to mass differences. The differences were observed for internal and external dose rates, but they were less pronounced for total dose rates which are typically used in the assessment of radiological impact. The results of the current work can serve as a basis for further studies of the radiological parameters in environments that have not been studied yet. (orig.)
Kulkarni, Arun Venkatesh
Pi-nuclear scattering calculations that use multiple scattering usually require the knowledge not only of the pi-nucleon interaction in free space but also its modification inside a nuclear medium. A relativistic 3-Body model consisting of the pion, the i^ {rm th}-nucleon and the residual nucleus also called the core, is developed. In this model the nucleon core separation in co-ordinate space is approximated by the separation between the center of mass of the pi-i^{rm th} nucleon subsystem called the Composite, and the core. The instant form of dynamics was employed to introduce interactions between the pion and the nucleon and between the pi N Composite and the Core. The Composite-Core Hamiltonian is assumed to admit no bound states. The relativistic 3-Body total Hamiltonian is then diagonalized by nested-separable eigenfunctions. This diagonalization allows the construction of an expression for matrix elements of the medium modified pi N scattering operator tau_ {i} in the lab frame in terms of the CM pi N free space t-matrix elements. Terms that are quadratic in the pi N t -matrix elements in this expression are neglected. The Sequential Single Charge eXchange (SSCX) mechanism contribution to inclusive pi- ^4He Double Charge eXchange (DCX) is calculated using only the double scattering term of the Watson multiple scattering series. The tau-matrix elements obtained from the 3-Body model are used for the first scattering. It contains explicit dependance upon the matrix elements of the Composite-Core scattering operator t_{pi N-C}. This explicit dependance is ignored in the second scattering. The pole of the intermediate pion Green function is fixed from 3-Body model considerations and the requirement that pion be on the mass shell at the pole. The calculated inclusive cross sections {{d^2sigma}over{d Omega dT_pi}} are compared with the Kinney et al. experimental results and essential agreement with the spectrum for incident pion kinetic energy T_sp{pi}{rm In
Energy Technology Data Exchange (ETDEWEB)
Tol, J.B.A. van; Stevens, R.M.M.; Veldhuizen, W.J.; Jongejan, J.A.; Duine, J.A. [Delft Univ. of Technology (Netherlands)
1995-07-05
When it is assumed that organic solvents do not interfere with the binding process nor with the catalytic mechanism, the contribution of substrate-solvent interactions to enzyme kinetics can be accounted for by just replacing substrate concentrations in the equations by thermodynamic activities. It appears from the transformation that only the affinity parameters (K{sub m},k{sub sp}) are affected by this. Thus, in theory, the values of these corrected, intrinsic parameters (K{sub m}{sup int}, k{sub sp}{sup int}) and the maximal rate (V{sub 1}) should be equal for all media. This was tested for hydrolysis, transesterification, and esterification reactions catalyzed by pig pancreas lipase and Pseudomonas cepacia lipase in various organic solvents. Correction was carried out via experimentally determined activity coefficients for the substrates in these solvents or, if not feasible, from values in data bases. However, although the kinetic performances of each enzyme in the solvents became much more similar after correction, differences still remained. Analysis of the enzyme suspensions revealed massive particles, which explains the low activity of enzymes in organic solvents. However, no correlation was found between estimates of the amount of catalytically available enzyme (present at the surface of suspended particles or immobilized on beads) and the maximal rates observed. Moreover, the solvents had similar effects on the intrinsic parameters of suspended and immobilized enzyme. The possible causes for the effects of the solvents on the catalytic performance of the enzymes, remaining after correction for solvent-substrate interactions and the amount of participating enzyme, are discussed with respect to the premises on which the correction method is based.
Li, Yuhui; Zhang, Shancai
2004-01-01
The high-gain harmonic generation (HGHG) free-electron laser (FEL) is an important candidate for a fourth-generation light source. Lots of theoretical work has been performed. Recently a further 1D theory about HGHG FEL has been developed. It considers the effects of different parameters for the whole process. An initial program based on this theory has been made. In this paper, a brief comparison of the results from this 1D program and from TDA (3D code) is discussed. It also analyses the parameters for Shanghai deep ultra violate free-electron laser source (SDUV-FEL), including electron beam energy spread, seed laser power, strength of dispersion section etc.
Energy Technology Data Exchange (ETDEWEB)
Bell, J.E.; Leone, A.; Bell, E.T.
1986-05-01
A glucosyltransferase, forming a predominantly al-6 linked glucan, was partially purified from the culture filtrate of S. mutans GS-5. The kinetic properties of the enzyme, assessed using the transfer of /sup 14/C glucose from sucrose into total glucan, were studied at pH values from pH 3.5 to 6.5. From the dependence of km on pH, a group with pKa = 5.5 must be protonated to maximize substrate binding. From plots of V/sub max/ vs pH two groups, with pKa's of 4.5 and 5.5 were indicated. The results suggest the involvement of either two carboxyl groups (one protonated, one unprotonated in the native enzyme) or a carboxyl group (unprotonated) and some other protonated group such as histidine, cysteine. Chemical modification studies showed that Diethylyrocarbonate (histidine specific) had no effect on enzyme activity while modification with p-phydroxy-mercuribenzoate or iodoacetic acid (sulfhydryl reactive) and carbodimide reagents (carboxyl specific) resulted in almost complete inactivation. Activity loss was dependent upon time of incubation and reagent concentration. The disaccharide lylose, (shown to be an inhibitor of the enzyme with similar affinity to sucrose) offers no protection against modification by the sulfhydryl reactive reagents.
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José E. Resende
2014-01-01
Full Text Available One serious consequence of the current consumer society is the transformation of the environment into a waste receptacle arising from human activities. Because of the potential toxic effects of chromium solid waste containing this metal there are grounds for serious concern for the tanning and leather processing industry. The application of tannery waste as organic fertilizer has led to extensive contamination by chromium in agricultural areas and may cause the accumulation of this metal in soils and plants. This work evaluated the extraction of Cr+3 and Cr+6 contained in solid waste from the leather industry through density functional theory (DFT calculations. The Gibbs free energy calculations reveal that the chelator ethylenediaminetetraacetic acid (EDTA forms more stable complexes with metal ions of chromium compared with the structures of the complexes [Cr(NTA(H2O2] and [Cr-collagen], the latter used to simulate the protein bound chrome leather.
One- and two-center ETF-integrals of first order in relativistic calculation of NMR parameters
Slevinsky, R. M.; Temga, T.; Mouattamid, M.; Safouhi, H.
2010-06-01
The present work focuses on the analytical and numerical developments of first-order integrals involved in the relativistic calculation of the shielding tensor using exponential-type functions as a basis set of atomic orbitals. For the analytical development, we use the Fourier integral transformation and practical properties of spherical harmonics and the Rayleigh expansion of the plane wavefunctions. The Fourier transforms of the operators were derived in previous work and they are used for analytical development. In both the one- and two-center integrals, Cauchy's residue theorem is used in the final developments of the analytical expressions, which are shown to be accurate to machine precision.
Wibowo, Scheling; Grauwet, Tara; Santiago, Jihan Santanina; Tomic, Jovana; Vervoort, Liesbeth; Hendrickx, Marc; Van Loey, Ann
2015-11-15
In view of understanding colour instability of pasteurised orange juice during storage, to the best of our knowledge, this study reports for the first time in a systematic and quantitative way on a range of changes in specific quality parameters as a function of time and as well as temperature (20-42 °C). A zero-order (°Brix, fructose, glucose), a first-order (vitamin C), a second-order (sucrose) and a fractional conversion model (oxygen) were selected to model the evolution of the parameters between parentheses. Activation energies ranged from 22 to 136 kJ mol(-1), HMF formation being the most temperature sensitive. High correlations were found between sugars, ascorbic acid, their degradation products (furfural and HMF) and total colour difference (ΔE(∗)). Based on PLS regression, the importance of the quality parameters for colour degradation was ranked relatively among each other: the acid-catalysed degradation of sugars and ascorbic acid degradation reactions appeared to be important for browning development in pasteurised orange juice during ambient storage. Copyright © 2015 Elsevier Ltd. All rights reserved.
Foda, Khaled; Abdeldaeim, Hussein; Youssif, Mohamed; Assem, Akram
2013-11-01
To define the parameters that accompanied a successful extracorporeal shock wave lithotripsy (ESWL), namely the number of shock waves (SWs), expulsion time (ET), mean stone density (MSD), and the skin-to-stone distance (SSD). A total of 368 patients diagnosed with renal calculi using noncontrast computerized tomography had their MSD, diameter, and SSD recorded. All patients were treated using a Siemens lithotripter. ESWL success meant a stone-free status or presence of residual fragments 934 HUs and SSD >99 mm. The required number of SWs and the expected ET can be anticipated. Copyright © 2013 Elsevier Inc. All rights reserved.
Kang, Sang-Won; Suh, Tae-Suk; Chung, Jin-Beom; Eom, Keun-Yong; Song, Changhoon; Kim, In-Ah; Kim, Jae-Sung; Lee, Jeong-Woo; Cho, Woong
2017-02-01
The purpose of this study was to evaluate the impact of dosimetric and radiobiological parameters on treatment plans by using different dose-calculation algorithms and delivery-beam modes for prostate stereotactic body radiation therapy using an endorectal balloon. For 20 patients with prostate cancer, stereotactic body radiation therapy (SBRT) plans were generated by using a 10-MV photon beam with flattening filter (FF) and flattening-filter-free (FFF) modes. The total treatment dose prescribed was 42.7 Gy in 7 fractions to cover at least 95% of the planning target volume (PTV) with 95% of the prescribed dose. The dose computation was initially performed using an anisotropic analytical algorithm (AAA) in the Eclipse treatment planning system (Varian Medical Systems, Palo Alto, CA) and was then re-calculated using Acuros XB (AXB V. 11.0.34) with the same monitor units and multileaf collimator files. The dosimetric and the radiobiological parameters for the PTV and organs at risk (OARs) were analyzed from the dose-volume histogram. An obvious difference in dosimetric parameters between the AAA and the AXB plans was observed in the PTV and rectum. Doses to the PTV, excluding the maximum dose, were always higher in the AAA plans than in the AXB plans. However, doses to the other OARs were similar in both algorithm plans. In addition, no difference was observed in the dosimetric parameters for different delivery-beam modes when using the same algorithm to generate plans. As a result of the dosimetric parameters, the radiobiological parameters for the two algorithm plans presented an apparent difference in the PTV and the rectum. The average tumor control probability of the AAA plans was higher than that of the AXB plans. The average normal tissue complication probability (NTCP) to rectum was lower in the AXB plans than in the AAA plans. The AAA and the AXB plans yielded very similar NTCPs for the other OARs. In plans using the same algorithms, the NTCPs for delivery
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Tait, Steven L.; Dohnalek, Zdenek; Campbell, Charles T.; Kay, Bruce D.
2006-12-21
We have measured the desorption of seven small n-alkanes (CNH2N+2, N = 1-4, 6, 8, 10) from the Pt(111) and C(0001) surfaces by temperature programmed desorption. We compare these results to our recent study of the desorption kinetics of these molecules on MgO(100) [J. Chem. Phys. 122, 164708 (2005)]. There we showed an increase in the desorption pre-exponential factor by several orders of magnitude with increasing n-alkane chain length and a linear desorption energy scaling with a small y-intercept value. We suggest that the significant increase in desorption prefactor with chain length is not particular to the MgO(100) surface, but is a general effect for desorption of the small n-alkanes. This argument is supported by statistical mechanical arguments for the increase in the entropy gain of the molecules upon desorption. In this work, we demonstrate that this hypothesis holds true on both a metal surface and a graphite surface. We observe an increase in prefactor by five orders of magnitude over the range of n-alkane chain lengths studied here. On each surface, the desorption energies of the n-alkanes are found to increase linearly with the molecule chain length and have a small y-intercept value. Prior results of other groups have yielded a linear desorption energy scaling with chain length that has unphysically large y-intercept values. We demonstrate that by allowing the prefactor to increase according to our model, a reanalysis of their data resolves this y-intercept problem to some degree.
LeMaster, Clifford; LeMaster, Carole; Greenwood, Benjamin; Butler, Drew; Cassidy, Keanan; Prince, Jonathan
2017-10-01
Rate constants obtained from total line-shape analysis of five temperature-dependent gas-phase NMR spectra of perfluoroazapropene yielded the kinetic barrier to internal isomerization: G‡298 = 66.9 (0.4) kJ mol-1. Five temperature-dependent liquid spectra (5 mol% in CDCl3) yielded G‡298 = 67.4 (0.8) kJ mol-1. Ab initio calculations performed using the compound methods Complete Basis Set (CBS-4M, QB3, APNO), Gaussian (G1-4), and Weizmann (W1U, WBD) gave results consistent with a transition state corresponding to nitrogen inversion. The values that best matched the experimental G‡298 value for each compound method were 63.9 kJ mol-1 (CBS-APNO), 66.1 kJ mol-1 (G2), and 65.6 kJ mol-1 (W1BD).
THERMODYNAMIC AND KINETIC PARAMETERS OF MIXTURES DESULFURIZING THE MADE WITH CaO, MgO, SiO2 AND CaF2
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Felipe Nylo de Aguiar
2012-09-01
Full Text Available This paper presents an analysis of the kinetics and thermodynamics of marble residue mixtures utilisation on desulfurization of pig iron. The desulfurization was carried out using lime, marble residue, fluorite and pig iron. Different mixtures of these materials were added into a bath of pig iron at 1,450°C. Metal samples were collected via vacuum samplers at times of 5, 10, 15, 20 and 30 minutes, in order to check the variation of sulfur content. Based on the results of chemical analysis of the metal and the desulfurizer mixture, the sulfide capacity of mixtures, the sulfur partition coefficient and the sulfur mass transport coefficient values were calculated.The results show the technical feasibility of using marble waste as desulfurizer agent.
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Niancheng Zhou
2014-08-01
Full Text Available The influence of electric vehicle charging stations on power grid harmonics is becoming increasingly significant as their presence continues to grow. This paper studies the operational principles of the charging current in the continuous and discontinuous modes for a three-phase uncontrolled rectification charger with a passive power factor correction link, which is affected by the charging power. A parameter estimation method is proposed for the equivalent circuit of the charger by using the measured characteristic AC (Alternating Current voltage and current data combined with the charging circuit constraints in the conduction process, and this method is verified using an experimental platform. The sensitivity of the current harmonics to the changes in the parameters is analyzed. An analytical harmonic model of the charging station is created by separating the chargers into groups by type. Then, the harmonic current amplification caused by the shunt active power filter is researched, and the analytical formula for the overload factor is derived to further correct the capacity of the shunt active power filter. Finally, this method is validated through a field test of a charging station.
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Chuan Wang
2013-01-01
Full Text Available In order to improve the efficiency of stainless steel stamping multistage pump, quadratic regression orthogonal test, hydraulic design, and computational fluid dynamics (CFD are used to analyze the effect of pump geometric parameters. Sixteen impellers are designed based on the quadratic regression orthogonal test, which have three factors including impeller outlet slope, impeller blade outlet stagger angle, and impeller blade outlet width. Through quadratic regression equation, the function relationship between efficiency values and three factors is established. The optimal combination of geometric parameters is found through the analysis of the regression equation. To further study the influence of blade thickness on the performance of multistage pump, numerical simulations of multistage pump with different blade thicknesses are carried out. The influence law of blade thickness on pump performance is built from the external characteristics and internal flow field. In conclusion, with the increase of blade thickness, the best efficiency point of the pump shifts to the small flow rate direction, and the vortex regions inside the pump at rated flow gradually increase, which is the main reason that pump efficiency decreases along with the increase of the blade thickness at rated flow.
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Fátima Resende Luiz Fia
2012-03-01
Full Text Available The objective of this study was to evaluate the performance of constructed wetland systems (SACs for treatment of swine wastewater (ARS under different organic loads (TCOA, and obtain kinetic parameters for sizing of the SACs. The SACs consisted of two tanks measuring 0.40 x 0.10 x 0.15 m, constructed of glass and filled with a 0.13 m layer of pea gravel; these were installed within a BOD incubator to maintain a 20°C temperature. The SACs were not cultivated and were submitted to average TCOA concentrations of 246 (SAC1 and 328 kg ha-1 day-1 of BOD (SAC2 for 51 days. With regard to the removal of organic matter, in the form of TSS, BOD and COD, no statistical difference was verified (p > 0.05 between the SACs, being that the average removal efficiencies for the referred variables in SAC1 and SAC2 were 68 and 76%, 66 and 73%, and 55 and 58%, respectively. The models proposed by Brasil et al. (2007 and Kadlec and Wallace (2008 presented good fit and adequately described the kinetics of organic matter removal (BOD and COD from the evaluated systems, generally presenting R2 greater than 99%.
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Smith, Gary L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2016-09-06
This report refers to or contains K_{g} values for glasses LAWA44, LAWB45 and LAWC22 affected by calculations errors as identified by Papathanassiu et al. (2011). The corrected K_{g} values are reported in an erratum included in the revised version of the original report. The revised report can be referenced as follows: Pierce E. M. et al. (2004) Waste Form Release Data Package for the 2005 Integrated Disposal Facility Performance Assessment. PNNL-14805 Rev. 0 Erratum. Pacific Northwest National Laboratory, Richland, WA, USA.
Zhao, Yu-Chen; Liu, Jiang-Fan; Song, Zhong-Guo; Xi, Xiao-Li
2014-12-01
Multi-needle zinc oxide whisker (M-ZnOw) includes tetrapod-needle ZnOw (T-ZnOw), flower-shaped ZnOw, and other similar ZnOw architectures. The unique three-dimensional (3D) and multi-needle-shaped structures give the special performance of M-ZnOw, but make it difficult to calculate the effective electromagnetic parameters of M-ZnOw composites. In this paper, based on the equivalent spherical particle and the strong fluctuation theory, three different closed-form expressions are presented to calculate the effective electromagnetic parameters of M-ZnOw composites. To start with, because of the macroscopic isotropic nature of M-ZnOw composites and lossy properties of M-ZnOw itself, an equivalent spherical particle is introduced in the scheme to simplify the unique microscopic structures of M-ZnOw, and the possible limitations of the presented equivalent spherical particle are discussed qualitatively. In addition, different closed-form expressions to calculate the effective electromagnetic parameter are obtained by means of representing the physical situations of conductive network as different correlation functions in the strong fluctuation theory. Finally, the effective permeability of a T-ZnOw/Fe - paraffin composite is calculated by these three expressions in 2-18 GHz frequency range. Very good agreement between the calculated and experimental results on one hand verifies the rationality of presented expressions, and on the other hand indicates that the correlation function plays an important role in improving the performance of the presented expression.
Martínez-Morillo, Eduardo; García, Belén Prieto; Calvo, Francisco Moreno; Alvarez, Francisco V
2012-03-01
To evaluate the population parameters applied to the calculation of risk for Down syndrome (DS) in the first trimester screening (FTS) and the comparison of performance obtained including or excluding maternal age from the mathematical algorithm. Three different calculation engines for prenatal risk of DS were developed on the basis of the population parameters from the Serum, Urine and Ultrasound Screening Study, the Fetal Medicine Foundation, and a combination of both of them. These calculators were evaluated in 14,645 first trimester pregnant women, including 59 DS affected fetuses, comparing their performance with that obtained by our commercial software Elipse® (Perkin Elmer Life and Analytical Sciences, Turku, Finland). Advanced first trimester screening (AFS) strategy was also analyzed, and a hybrid strategy (FTS + AFS) was evaluated. By selecting population parameters from the Serum, Urine and Ultrasound Screening Study, the detection rate increased from 76% (Elipse) to 86% with a small increase in the false positive rate (FPR), from 3.3% to 3.7%, respectively. DS screening performance significantly improved by using the hybrid strategy (AFS in pregnant women under 35 years and FTS in pregnant women over 35 years), with a 92% detection rate (FPR: 3.9%). In the present study, a new hybrid screening strategy has been proposed to achieve DS detection rates higher than 90%, for a convenient <4% FPR. © 2012 John Wiley & Sons, Ltd.
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Stepanenko E. I.
2016-09-01
Full Text Available The dependence of water activity on basic physical and chemical characteristics of salted fish products with intermediate moisture has been defined. During the research the product quality has been assessed by the organoleptic method; determination of the water mass fraction has been carried out by the drying method; the salt mass fraction – by the argentometric method; water activity has been measured by a cooled mirror dew-point sensor. Based on experimental data the dependence of Aw on concentration of sodium chloride in the salt semi-finished products of pollock (Theragra chalcogramma, Atlantic herring (Clupea harengus, Baltic cod (Gadus morhua callarias, blue whiting (Micromesistius, pink salmon (Oncorhynchus gorbuscha, horse mackerel (Trachurus trachurus has been established. The empirical formula showing the correlation of the parameter (Aw with mass fraction of sodium chloride and water has been derived; on its basis it is possible to calculate the parameters of semi-finished product in order to obtain a final minced salt product of intermediate moisture with desired microbial stability upon storage. The relations between the salt mass fraction and water mass fraction excluding bacterial spoilage and mold growth has been determined, they make up S ≥ 0,135 ∙ W and S ≥ 0,34 ∙ W respectively, where S – the mass fraction of salt, %, W – the mass fraction of water, %. An example of calculating the required dosage of sodium chloride in the semi-finished minced salmon has been described to produce the finished product with the exactly given values of humidity and water activity. During the process of minced salted fish products' dehydration the basic physical and chemical parameters – the mass fraction of salt and water affecting the water activity (Aw – have been changing. Determination of these parameters' relationship provides the ability to predict the qualitative changes of salted fish products of intermediate moisture
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Agafonova, Evgeniia V., E-mail: agafonova.ev@samgtu.ru [Samara State Technical University, Molodogvardeyskaya 244, 443100 Samara (Russian Federation); Moshchenskiy, Yuriy V. [Samara State Technical University, Molodogvardeyskaya 244, 443100 Samara (Russian Federation); Tkachenko, Mikhail L., E-mail: tka-mikhail@yandex.ru [Samara State Medical University, Chapaevskaya 89, 443099 Samara (Russian Federation)
2014-03-01
Highlights: • The system clarithromycin–metronidazole is a system with a simple eutectic. • The eutectic melting temperature for the system clarithromycin–metronidazole is 155.2 ± 0.5 °C and it is not changed by varying the composition of the system. • The DSC curve for the composition of 89:11 mol or 64.9:35.1 wt% corresponds to the eutectic (or the invariant) composition for the system clarithromycin–metronidazole. - Abstract: In this study melting thermodynamic characteristics of clarithromycin and metronidazole as individual substances were investigated by DSC method. It was found that the binary system of clarithromycin and metronidazole is a system with simple eutectic. Composition, melting temperature and the heat of fusion of the eutectic were determined by calculation and experimental methods.
Behrens, F; Mackeben, M; Schröder-Preikschat, W
2010-08-01
This analysis of time series of eye movements is a saccade-detection algorithm that is based on an earlier algorithm. It achieves substantial improvements by using an adaptive-threshold model instead of fixed thresholds and using the eye-movement acceleration signal. This has four advantages: (1) Adaptive thresholds are calculated automatically from the preceding acceleration data for detecting the beginning of a saccade, and thresholds are modified during the saccade. (2) The monotonicity of the position signal during the saccade, together with the acceleration with respect to the thresholds, is used to reliably determine the end of the saccade. (3) This allows differentiation between saccades following the main-sequence and non-main-sequence saccades. (4) Artifacts of various kinds can be detected and eliminated. The algorithm is demonstrated by applying it to human eye movement data (obtained by EOG) recorded during driving a car. A second demonstration of the algorithm detects microsleep episodes in eye movement data.
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Zhang Rui; Franz, Jan; Tennyson, Jonathan [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Baluja, K L, E-mail: j.tennyson@ucl.ac.uk [Department of Physics and Astrophysics University of Delhi, Delhi 110 007 (India)
2011-01-14
The molecular R-matrix with pseudo-states (MRMPS) method is employed to study positron collisions with H{sub 2}. The calculations employ pseudo-continuum orbital sets containing up to h (l = 5) functions. Use of these high l functions is found to give converged eigenphase sums. Below the positronium formation threshold, the calculated cross sections agree with other high-accuracy theories and generally with the measurements. Calculation of the positron annihilation parameter Z{sub eff} with the MRMPS wavefunctions gives values significantly higher than other R-matrix wavefunctions but still do not completely converge with h functions. Extrapolation to higher l-values leads to a predicted value of Z{sub eff} for H{sub 2} of about 10.4. The MRMPS method is both completely general and ab initio; it can therefore be applied to positron collisions with other molecular targets.
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L Mousavi Seresht
2014-01-01
Full Text Available Background : Appropriate determination of tidal volume (VT is important for preventing ventilation induced lung injury. We compared hemodynamic and respiratory parameters in two conditions of receiving VTs calculated by using body weight (BW, which was estimated by measured height (HBW or demi-span based body weight (DBW. Materials and Methods : This controlled-trial was conducted in St. Alzahra Hospital in 2009 on American Society of Anesthesiologists (ASA I and II, 18-65-years-old patients. Standing height and weight were measured and then height was calculated using demi-span method. BW and VT were calculated with acute respiratory distress syndrome-net formula. Patients were randomized and then crossed to receive ventilation with both calculated VTs for 20 min. Hemodynamic and respiratory parameters were analyzed with SPSS version 20.0 using univariate and multivariate analyses. Results : Forty nine patients were studied. Demi-span based body weight and thus VT (DTV were lower than Height based body weight and VT (HTV (P = 0.028, in male patients (P = 0.005. Difference was observed in peak airway pressure (PAP and airway resistance (AR changes with higher PAP and AR at 20 min after receiving HTV compared with DTV. Conclusions : Estimated VT based on measured height is higher than that based on demi-span and this difference exists only in females, and this higher VT results higher airway pressures during mechanical ventilation.
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Mahsa Ghovvati
2016-03-01
Full Text Available Almost all optimization techniques are restricted by the problems' dimensions and large search spaces. This research focuses on a special hybrid method combining two meta-heuristic techniques, genetic algorithms (GA and particle swarm optimization (PSO that aims at overcoming this issue. This method investigates the potential impact of constraints (or the feasible regions on the search pattern of GA and PSO. The proposed algorithm was applied for parameter estimation of batch fermentation process for alkaline protease production by Bacillus licheniformis in submerged culture. Furthermore, a comparison of proposed hybrid GA/PSO with pure GA and pure PSO was carried out. The results revealed that combination of these two meta-heuristic algorithms speeds up the search (about two-fold faster in comparison to pure algorithms, since it benefits from synergy. Hence, the proposed method can be considered as an applicable method for parameter estimation of biological models in particular for large search space problems. Also, it was concluded that PSO has a slightly better performance and possesses better convergence and computational time than GA.
Fontes, R; Ribeiro, J M; Sillero, A
2000-01-01
A combined analysis of enzyme inhibition and activation is presented, based on a rapid equilibrium model assumption in which one molecule of enzyme binds one molecule of substrate (S) and/or one molecule of a modifier X. The modifier acts as activator (essential or non-essential), as inhibitor (total or partial), or has no effect on the reaction rate (v), depending on the values of the equilibrium constants, the rate constants of the limiting velocity steps, and the concentration of substrate ([S]). Different possibilities have been analyzed from an equation written to emphasize that v = f([X]) is, in general and at a fixed [S], a hyperbolic function. Formulas for Su (the value of [S], different from zero, at which v is unaffected by the modifier) and v(su) (v at that particular [S]) were deduced. In Lineweaver-Burk plots, the straight lines related to different [X] generally cross in a point (P) with coordinates (Su, v(su)). In certain cases, point P is located in the first quadrant which implies that X acts as activator, as inhibitor, or has no effect, depending on [S]. Furthermore, we discuss: (1) the apparent Vmax and Km displayed by the enzyme in different situations; (2) the degree of effect (inhibition or activation) observed at different concentrations of substrate and modifier; (3) the concept of Ke, a parameter that depends on the concentration of substrate and helps to evaluate the effect of the modifier: it equals the value of [X] at which the increase or decrease in the reaction rate is half of that achieved at saturating [X]. Equations were deduced for the general case and for particular situations, and used to obtain computer-drawn graphs that are presented and discussed. Formulas for apparent Vmax, Km and Ke have been written in a way making it evident that these parameters can be expressed as pondered means.
Deboosere, N; Legeay, O; Caudrelier, Y; Lange, M
2004-05-15
While thermal destruction of pathogenic bacteria has been thoroughly studied in food industry, heat inactivation of viruses in food has been poorly investigated. Experiments were carried out to characterize the effects of controlled physical and chemical characteristics of a food matrix upon heat resistance parameters (D and z values) of hepatitis A virus (HAV), taken as model because of its reported heat resistance. Sucrose content (28-52 degrees Brix), calcium concentration (90-1700 mg kg(-1)) and pH (3.3-4.3) were selected for possible influence on thermal inactivation of HAV in strawberry mashes and thus included in an experimental design according to a Doehlert matrix. Use of this design not only allowed to detect and quantify the direct influence of sucrose concentration upon the D85 degrees C value to be higher than the one of pH, but also to reveal a sucrose concentration/pH specific interaction, while no effect of calcium concentration was evidenced. Although the model cannot be directly used to predict heat resistance in real fruit systems, because of differences observed between predicted and measured D85 degrees C values, it is useful for predicting the trends and relative changes in D values due to sucrose concentration and pH variations. Results suggested possible effects of other constituents of strawberry products on heat resistance of HAV and confirmed the importance of experimental validation of any model-derived process. Nevertheless, such a modelling approach using response surface methodology provides a rapid answer to heat resistance evaluation of a food-borne virus as a function of specific physical and chemical parameters of specific food products. Copyright 2003 Elsevier B.V.
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M. H. Denton
2008-03-01
Full Text Available Moments calculated from the ion distributions (~0–40 keV measured by the Cluster Ion Spectrometry (CIS instrument are combined with data from the Cluster Flux Gate Magnetometer (FGM instrument and used to characterise the bulk properties of the plasma in the near-Earth magnetosphere over five years (2001–2005. Results are presented in the form of 2-D xy, xz and yz GSM cuts through the magnetosphere using data obtained from the Cluster Science Data System (CSDS and the Cluster Active Archive (CAA. Analysis reveals the distribution of ~0–40 keV ions in the inner magnetosphere is highly ordered and highly responsive to changes in solar wind velocity. Specifically, elevations in temperature are found to occur across the entire nightside plasma sheet region during times of fast solar wind. We demonstrate that the nightside plasma sheet ion temperature at a downtail distance of ~12 to 19 Earth radii increases by a factor of ~2 during periods of fast solar wind (500–1000 km s^{−1} compared to periods of slow solar wind (100–400 km s^{−1}. The spatial extent of these increases are shown in the xy, xz and yz GSM planes. The results from the study have implications for modelling studies and simulations of solar-wind/magnetosphere coupling, which ultimately rely on in situ observations of the plasma sheet properties for input/boundary conditions.
Mahieux, Arnaud; Goldstein, David B.; Varghese, Philip; Trafton, Laurence M.
2017-10-01
The vapor and particulate plumes arising from the southern polar regions of Enceladus are a key signature of what lies below the surface. Multiple Cassini instruments (INMS, CDA, CAPS, MAG, UVIS, VIMS, ISS) measured the gas-particle plume over the warm Tiger Stripe region and there have been several close flybys. Numerous observations also exist of the near-vent regions in the visible and the IR. The most likely source for these extensive geysers is a subsurface liquid reservoir of somewhat saline water and other volatiles boiling off through crevasse-like conduits into the vacuum of space.In this work, we use a DSMC code to simulate the plume as it exits a vent, considering axisymmetric conditions, in a vertical domain extending up to 10 km. Above 10 km altitude, the flow is collisionless and well modeled in a separate free molecular code. We perform a DSMC parametric and sensitivity study of the following vent parameters: vent diameter, outgassed flow density, water gas/water ice mass flow ratio, gas and ice speed, and ice grain diameter. We build parametric expressions of the plume characteristics at the 10 km upper boundary (number density, temperature, velocity) that will be used in a Bayesian inversion algorithm in order to constrain source conditions from fits to plume observations by various instruments on board the Cassini spacecraft and assess the parametric sensitivity study.
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Hassan Maktuff Jaber Al-Ta'ii
2015-02-01
Full Text Available Many types of materials such as inorganic semiconductors have been employed as detectors for nuclear radiation, the importance of which has increased significantly due to recent nuclear catastrophes. Despite the many advantages of this type of materials, the ability to measure direct cellular or biological responses to radiation might improve detector sensitivity. In this context, semiconducting organic materials such as deoxyribonucleic acid or DNA have been studied in recent years. This was established by studying the varying electronic properties of DNA-metal or semiconductor junctions when exposed to radiation. In this work, we investigated the electronics of aluminium (Al/DNA/silicon (Si rectifying junctions using their current-voltage (I-V characteristics when exposed to alpha radiation. Diode parameters such as ideality factor, barrier height and series resistance were determined for different irradiation times. The observed results show significant changes with exposure time or total dosage received. An increased deviation from ideal diode conditions (7.2 to 18.0 was observed when they were bombarded with alpha particles for up to 40 min. Using the conventional technique, barrier height values were observed to generally increase after 2, 6, 10, 20 and 30 min of radiation. The same trend was seen in the values of the series resistance (0.5889–1.423 Ω for 2–8 min. These changes in the electronic properties of the DNA/Si junctions could therefore be utilized in the construction of sensitive alpha particle detectors.
Aral, Serdar; Beşe, Ayşe Vildan
2016-11-01
Thin layer drying characteristics and physicochemical properties of hawthorn fruit (Crataegus spp.) were investigated using a convective dryer at air temperatures 50, 60 and 70°C and air velocities of 0.5, 0.9 and 1.3m/s. The drying process of hawthorn took place in the falling rate period, and the drying time decreased with increasing air temperature and velocity. The experimental data obtained during the drying process were fitted to eleven different mathematical models. The Midilli et al.'s model was found to be the best appropriate model for explaining the drying behavior of hawthorn fruit. Effective moisture diffusion coefficients (Deff) were calculated by Fick's diffusion model and their values varied from 2.34×10(-10)m(2)/s to 2.09×10(-9)m(2)/s. An Arrhenius-type equation was applied to determine the activation energies. While the shrinkage decreased, the rehydration ratio increased with increasing air temperature and air velocity. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Uddin, M.N. [Department of Physics, Jahangirnagar University, Dhaka (Bangladesh); Sarker, M.M. [Reactor Physics and Engineering Division, Institute of Nuclear Science and Technology, Atomic Energy Research Establishment, Savar, GPO Box 3787, Dhaka 1000 (Bangladesh); Khan, M.J.H. [Reactor Physics and Engineering Division, Institute of Nuclear Science and Technology, Atomic Energy Research Establishment, Savar, GPO Box 3787, Dhaka 1000 (Bangladesh)], E-mail: jahirulkhan@yahoo.com; Islam, S.M.A. [Department of Physics, Jahangirnagar University, Dhaka (Bangladesh)
2009-10-15
The aim of this paper is to present the validation of evaluated nuclear data files CENDL-2.2 and JEFF-3.1.1 through the analysis of the integral parameters of TRX and BAPL benchmark lattices of thermal reactors for neutronics analysis of TRIGA Mark-II Research Reactor at AERE, Bangladesh. In this process, the 69-group cross-section library for lattice code WIMS was generated using the basic evaluated nuclear data files CENDL-2.2 and JEFF-3.1.1 with the help of nuclear data processing code NJOY99.0. Integral measurements on the thermal reactor lattices TRX-1, TRX-2, BAPL-UO{sub 2}-1, BAPL-UO{sub 2}-2 and BAPL-UO{sub 2}-3 served as standard benchmarks for testing nuclear data files and have also been selected for this analysis. The integral parameters of the said lattices were calculated using the lattice transport code WIMSD-5B based on the generated 69-group cross-section library. The calculated integral parameters were compared to the measured values as well as the results of Monte Carlo Code MCNP. It was found that in most cases, the values of integral parameters show a good agreement with the experiment and MCNP results. Besides, the group constants in WIMS format for the isotopes U-235 and U-238 between two data files have been compared using WIMS library utility code WILLIE and it was found that the group constants are identical with very insignificant difference. Therefore, this analysis reflects the validation of evaluated nuclear data files CENDL-2.2 and JEFF-3.1.1 through benchmarking the integral parameters of TRX and BAPL lattices and can also be essential to implement further neutronic analysis of TRIGA Mark-II research reactor at AERE, Dhaka, Bangladesh.
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Mojtaba Ahmadi
2016-11-01
Full Text Available The aqueous degradation of Reactive Yellow 84 (RY84 by potassium peroxydisulfate (K2S2O8 has been studied in laboratory scale experiments. The effect of the initial concentrations of potassium peroxydisulfate and RY84, pH and temperature on RY84 degradation were also examined. Experimental data were analyzed using first and second-order kinetics. The degradation kinetics of RY84 of the potassium peroxydisulfate process followed the second-order reaction kinetics. These rate constants have an extreme values similar to of 9.493 mM−1min−1 at a peroxydisulfate dose of 4 mmol/L. Thermodynamic parameters such as activation (Ea and Gibbs free energy (ΔG° were also evaluated. The negative value of ΔGo and Ea shows the spontaneous reaction natural conditions and exothermic nature.
A kinetic model of reversion type cure for rubber compounds
Energy Technology Data Exchange (ETDEWEB)
Han, I.S.; Chung, C.B.; Kang, S.J.; Kim, S.J. [Chonnam National University, Kwangju (Korea, Republic of); Jung, H.C. [Research and Development Center of Kumho Tire Co., Ltd., Kwangju (Korea, Republic of)
1998-03-01
A cure kinetic model was presented to explain the reversion and the induction period commonly found in the vulcanization of rubber compounds. The model has three kinetic rate constants and one induction time which should be determined on the basis of isothermal rheometer curves. The torque curves calculated using the estimated parameters showed an excellent agreement with the measured curves for two rubber samples. An Arrhenius type relation was adopted to account for the temperature dependence of each kinetic parameter, and the corresponding Arrhenius plot showed very good linearity. It was shown that the proposed model can be used for predicting the state of cure for rubber compounds which undergo nonisothermal cure steps.
Directory of Open Access Journals (Sweden)
Raziyeh Zandipak
2016-02-01
Full Text Available Background: Among different pollutants released into the environment, dyes are considered as one of the most dangerous contaminants. In recent years, magnetic nanomaterials have attracted much attention for their dye removal capacity. The aim of this study was to explore the adsorption kinetics of an anionic dye (Reactive Orange 13 (RO by NiFe2O4 nanoparticles (NiFe2O4 NPs under various conditions. Methods: NiFe2O4 nanoparticles (NiFe2O4 NPs were prepared and characterized by X-ray diffraction (XRD, transmission electronic microscopy (TEM, pHpzc and BET methods. The adsorption characteristics of the NiFe2O4 NPs adsorbent were examined using Reactive Orange 13 as an adsorbate. The influences of parameters including pH, dose of adsorbent and contact time were investigated to find the optimum adsorption conditions. Results: Decreasing solution pH and increasing contact time were favorable for improving adsorption efficiency. The kinetic and isotherm data of RO adsorption on NiFe2O4 NPs were well fitted by pseudo-second-order and Langmuir models, respectively. Conclusion: The maximal adsorption capacity of RO was 243.9 mg g-1 at 25◦C and pH 3.0 and the adsorption of RO on the NiFe2O4 NPs follows a monolayer coverage model. NiFe2O4 NPs might be an effective and potential adsorbent for removing anionic dyes from aqueous solutions.
Ratelle, Mylène; Coté, Jonathan; Bouchard, Michèle
2015-12-01
Biomonitoring of pyrethroid exposure is largely conducted but human toxicokinetics has not been fully documented. This is essential for a proper interpretation of biomonitoring data. Time profiles and toxicokinetic parameters of key biomarkers of exposure to cypermethrin in orally exposed volunteers have been documented and compared with previously available kinetic data following permethrin dosing. Six volunteers ingested 0.1 mg kg(-1) bodyweight of cypermethrin acutely. The same volunteers were exposed to permethrin earlier. Blood samples were taken over 72 h after treatment and complete timed urine voids were collected over 84 h postdosing. Cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acids (trans- and cis-DCCA) and 3-phenoxybenzoic acid (3-PBA) metabolites, common to both cypermethrin and permethrin, were quantified. Blood and urinary time courses of all three metabolites were similar following cypermethrin and permethrin exposure. Plasma levels of metabolites reached peak values on average ≈ 5-7 h post-dosing; the elimination phase showed mean apparent half-lives (t½ ) for trans-DCCA, cis-DCCA and 3-PBA of 5.1, 6.9 and 9.2 h, respectively, following cypermethrin treatment as compared to 7.1, 6.2 and 6.5 h after permethrin dosing. Corresponding mean values obtained from urinary rate time courses were peak values at ≈ 9 h post-dosing and apparent elimination t½ of 6.3, 6.4 and 6.4 h for trans-DCCA, cis-DCCA and 3-PBA, respectively, following cypermethrin treatment as compared to 5.4, 4.5 and 5.7 h after permethrin dosing. These data confirm that the kinetics of cypermethrin is similar to that of permethrin in humans and that their common biomarkers of exposure may be used for an overall assessment of exposure. Copyright © 2015 John Wiley & Sons, Ltd.
Bisetti, Fabrizio
2014-01-02
The effects of an electric field on the collision rates, energy exchanges and transport properties of electrons in premixed flames are investigated via solutions to the Boltzmann kinetic equation. The case of high electric field strength, which results in high-energy, non-thermal electrons, is analysed in detail at sub-breakdown conditions. The rates of inelastic collisions and the energy exchange between electrons and neutrals in the reaction zone of the flame are characterised quantitatively. The analysis includes attachment, ionisation, impact dissociation, and vibrational and electronic excitation processes. Our results suggest that Townsend breakdown occurs for E/N = 140 Td. Vibrational excitation is the dominant process up to breakdown, despite important rates of electronic excitation of CO, CO2 and N2 as well as impact dissociation of O2 being apparent from 50 Td onwards. Ohmic heating in the reaction zone is found to be negligible (less than 2% of peak heat release rate) up to breakdown field strengths for realistic electron densities equal to 1010 cm-3. The observed trends are largely independent of equivalence ratio. In the non-thermal regime, electron transport coefficients are insensitive to mixture composition and approximately constant across the flame, but are highly dependent on the electric field strength. In the thermal limit, kinetic parameters and transport coefficients vary substantially across the flame due to the spatially inhomogeneous concentration of water vapour. A practical approach for identifying the plasma regime (thermal versus non-thermal) in studies of electric field effects on flames is proposed. © 2014 Taylor & Francis.
Pradines, B; Arras, R.; Calmels, L
2017-01-01
We present an ab initio study of the influence of the tetragonal distortion, on the static and dynamic (Gilbert damping parameter) magnetic properties of a Co2MnSi crystal. This tetragonal distortion can for instance be due to strain, when Co2MnSi is grown on a substrate with a small lattice mismatch. Using fully relativistic Korringa-Kohn-Rostoker (KKR) calculations, in conjunction with the coherent potential approximation (CPA) to describe atomic disorder and the linear response formalism t...
Directory of Open Access Journals (Sweden)
Mitchell Schulte
2009-06-01
Full Text Available The citric acid cycle (CAC is the central pathway of energy transfer for many organisms, and understanding the origin of this pathway may provide insight into the origins of metabolism. In order to assess the thermodynamics of this key pathway for microorganisms that inhabit a wide variety of environments, especially those found in high temperature environments, we have calculated the properties and parameters for the revised Helgeson-Kirkham-Flowers equation of state for the major components of the CAC. While a significant amount of data is not available for many of the constituents of this fundamental pathway, methods exist that allow estimation of these missing data.
Energy Technology Data Exchange (ETDEWEB)
Santos, Rubens Souza dos [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil); Martinez, Aquilino Senra; Alvim, Antonio Carlos Marques [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear
2002-07-01
In this work is presented a methodology which focuses the distribution of neutron absorber rods in nuclear reactor power plants, for utilizing in space kinetic calculations, principally in the cluster ejection transients of control rods. A numerical model for macroscopic constant calculations based on the knowledge of the neutron flux without the control rods is proposed, as alternative to the analytical models, based on the hypothesis of the null current on the cell super boundaries. The proposed model in this work has itself showed adequate to deal with problems with strong space dependence, once that the model showed consistence in the global average built in the analytical model. (author)
Luquot, L.; Hebert, V.; Rodriguez, O.
2015-11-01
The aim of this study is to compare the structural, geometrical and transport parameters of a limestone rock sample determined by X-ray microtomography (XMT) images and laboratory experiments. Total and effective porosity, surface-to-volume ratio, pore size distribution, permeability, tortuosity and effective diffusion coefficient have been estimated. Sensitivity analyses of the segmentation parameters have been performed. The limestone rock sample studied here have been characterized using both approaches before and after a reactive percolation experiment. Strong dissolution process occured during the percolation, promoting a wormhole formation. This strong heterogeneity formed after the percolation step allows to apply our methodology to two different samples and enhance the use of experimental techniques or XMT images depending on the rock heterogeneity. We established that for most of the parameters calculated here, the values obtained by computing XMT images are in agreement with the classical laboratory measurements. We demonstrated that the computational porosity is more informative than the laboratory one. We observed that pore size distributions obtained by XMT images and laboratory experiments are slightly different but complementary. Regarding the effective diffusion coefficient, we concluded that both approaches are valuable and give similar results. Nevertheless, we wrapped up that computing XMT images to determine transport, geometrical and petrophysical parameters provides similar results than the one measured at the laboratory but with much shorter durations.
Luquot, Linda; Hebert, Vanessa; Rodriguez, Olivier
2016-03-01
The aim of this study is to compare the structural, geometrical and transport parameters of a limestone rock sample determined by X-ray microtomography (XMT) images and laboratory experiments. Total and effective porosity, pore-size distribution, tortuosity, and effective diffusion coefficient have been estimated. Sensitivity analyses of the segmentation parameters have been performed. The limestone rock sample studied here has been characterized using both approaches before and after a reactive percolation experiment. Strong dissolution process occurred during the percolation, promoting a wormhole formation. This strong heterogeneity formed after the percolation step allows us to apply our methodology to two different samples and enhance the use of experimental techniques or XMT images depending on the rock heterogeneity. We established that for most of the parameters calculated here, the values obtained by computing XMT images are in agreement with the classical laboratory measurements. We demonstrated that the computational porosity is more informative than the laboratory measurement. We observed that pore-size distributions obtained by XMT images and laboratory experiments are slightly different but complementary. Regarding the effective diffusion coefficient, we concluded that both approaches are valuable and give similar results. Nevertheless, we concluded that computing XMT images to determine transport, geometrical, and petrophysical parameters provide similar results to those measured at the laboratory but with much shorter durations.
Lysenko, Vladimir
2012-05-01
Residual chlorophyll in chlorophyll-deficient (albino) areas of variegated leaves of Ficus benjamina originates from guard cell chloroplasts. Photosynthetic features of green and albino sectors of F. benjamina were studied by imaging the distribution of the fluorescence decrease ratio Rfd within a leaf calculated from maximum (Fm) and steady-state leaf chlorophyll fluorescence (Fs) at 690 and 740 nm. Local areas of albino sectors demonstrated an abnormally high Rfd(740)/Rfd(690) ratio. Fluorescence transients excited in albino sectors at red (640 and 690 nm) wavelengths showed an abrupt decrease of the Rfd values (0.4 and 0.1, correspondingly) as compared with those excited at blue wavelengths (1.7-2.4). This "Red Drop" was not observed for green sectors. Normal and chlorophyll-deficient leaf sectors of F. benjamina were also tested for linear and cyclic electron transport in thylakoids. The tests have been performed studying fluorescence at a steady-state phase with CO(2)-excess impulse feeding, photoacoustic signal generated by pulse light source at wavelengths selectively exciting PSI, fluorescence kinetics under anaerobiosis and fluorescence changes observed by dual-wavelength excitation method. The data obtained for albino sectors strongly suggest the possibility of a cyclic electron transport simultaneously occurring in guard cell thylakoids around photosystems I and II under blue light, whereas linear electron transport is absent or insufficient.
Dioguardi, Fabio; Dellino, Pierfrancesco
2014-05-01
PYFLOW is a computer code designed for quantifying the hazard related to Dilute Pyroclastic Density Currents (DPDC). DPDCs are multiphase flows that form during explosive volcanic eruptions. They are the major source of hazard related to volcanic eruptions, as they exert a significant stress over buildings and transport significant amounts of volcanic ash, which is hot and unbreathable. The program calculates the DPDC's impact parameters (e.g. dynamic pressure and particle volumetric concentration) and is founded on the turbulent boundary layer theory adapted to a multiphase framework. Fluid-dynamic variables are searched with a probabilistic approach, meaning that for each variable the average, maximum and minimum solutions are calculated. From these values, PYFLOW creates probability functions that allow to calculate the parameter at a given percentile. The code is written in Fortran 90 and can be compiled and installed on Windows, Mac OS X, Linux operating systems (OS). A User's manual is provided, explaining the details of the theoretical background, the setup and running procedure and the input data. The model inputs are DPDC deposits data, e.g. particle grainsize, layer thickness, particles shape factor and density. PYFLOW reads input data from a specifically designed input file or from the user's direct typing by command lines. Guidelines for writing input data are also contained in the package. PYFLOW guides the user at each step of execution, asking for additional data and inputs. The program is a tool for DPDC hazard assessment and, as an example, an application to the DPDC deposits of the Agnano-Monte Spina eruption (4.1 ky BP) at Campi Flegrei (Italy) is presented.
Bandura, A V; Sofo, J O; Kubicki, J D
2006-04-27
Plane-wave density functional theory (DFT-PW) calculations were performed on bulk SnO2 (cassiterite) and the (100), (110), (001), and (101) surfaces with and without H2O present. A classical interatomic force field has been developed to describe bulk SnO2 and SnO2-H2O surface interactions. Periodic density functional theory calculations using the program VASP (Kresse et al., 1996) and molecular cluster calculations using Gaussian 03 (Frisch et al., 2003) were used to derive the parametrization of the force field. The program GULP (Gale, 1997) was used to optimize parameters to reproduce experimental and ab initio results. The experimental crystal structure and elastic constants of SnO2 are reproduced reasonably well with the force field. Furthermore, surface atom relaxations and structures of adsorbed H2O molecules agree well between the ab initio and force field predictions. H2O addition above that required to form a monolayer results in consistent structures between the DFT-PW and classical force field results as well.
Sugawara, Hirotake
2017-04-01
A propagator method (PM), a numerical technique to solve the Boltzmann equation (BE) for the electron velocity or energy distribution function (EVDF/EEDF) of electron swarms in gases, was customized to obtain the equilibrium solution quickly. The PM calculates the number of electrons in cells defined in velocity space using an operator called the propagator or Green’s function. The propagator represents the intercellular transfer of electrons corresponding to the electron velocity change due to the acceleration by the electric field and the collisional events with gas molecules. The relaxation of the EVDF to its drift equilibrium solution proceeds with iterative propagator operations for the EVDF. Merits of the PM are that the series expansion of the EVDF as done in the BE analyses is not required and that time evolution of the electron swarm can be observed if necessary. On the other hand, in case only the equilibrium solution of the EVDF is wanted, the relaxation can be accelerated numerically. A demonstration achieved a shortening of the computational time by about three orders of magnitude. Furthermore, this scheme was applied to calculations of a set of electron transport parameters required in fluid-model simulations, i.e. the effective ionization frequency, the centroid drift velocity and the longitudinal diffusion coefficient, using the zeroth-, first- and second-order moment equations derived from the BE. A detailed description on the PM calculation was presented.
Energy Technology Data Exchange (ETDEWEB)
Marie, S. [CEA Saclay, DEN/DM2S/SEMT/LISN, 91191 Gif sur Yvette Cedex (France)], E-mail: stephane.marie@cea.fr; Chapuliot, S.; Kayser, Y. [CEA Saclay, DEN/DM2S/SEMT/LISN, 91191 Gif sur Yvette Cedex (France); Lacire, M.H. [CEA Saclay, DEN/DDIN, 91191 Gif sur Yvette Cedex (France); Drubay, B. [CEA Saclay, DEN/DM2S/SEMT/LISN, 91191 Gif sur Yvette Cedex (France); Barthelet, B. [EDF/EPN, Site Cap Ampere, 1 Place Pleyel 93207, Saint Denis Cedex 1 (France); Le Delliou, P. [EDF Pole Industrie - Division R and D, Site des Renardieres, Route de Sens, Ecuelles, 77250 Moret sur Loing Cedex (France); Rougier, V. [EDF/UTO, SIS/GAM, 6, Avenue Montaigne, 93192 Noisy le Grand (France); Naudin, C. [EDF/SEPTEN, 12-14, avenue Dutrievoz, 69628 Villeurbanne Cedex (France); Gilles, P.; Triay, M. [AREVA ANP, Tour AREVA, 92084 Paris La Defense Cedex 16 (France)
2007-10-15
Two French nuclear codes include flaw assessment procedures: the RSE-M Code 'Rules for In-service Inspection of Nuclear Power Plant Components' and the RCC-MR code 'Design and Construction rules for mechanical components of FBR nuclear islands and high temperature applications'. Development of analytical methods has been made for the last 10 years through a collaboration between CEA, EDF and AREVA-NP, and through R and D actions involving CEA and IRSN. These activities have led to unification of the common methods of the two codes. The calculation of fracture mechanics parameters, and in particular the stress intensity factor K{sub I} and the J integral, has been widely developed for industrial configurations. All the developments have been integrated in the 2005 edition of RSE-M and in 2007 edition of RCC-MR. This series of papers is composed of five parts: the first presents an overview of the methods proposed in the RCC-MR and RSE-M codes. Parts II-IV provide compendia for specific components. The geometries are plates (part II), pipes (part III) and elbows (part IV). Part V presents validation of the methods, with details on their accuracy. This paper presents the stress intensity factor and J calculation for cracked elbows. General data applicable for all defect geometries are first presented, and then, compendia for K{sub I} and {sigma}{sub ref} calculations are provided for the available defect geometries.
Energy Technology Data Exchange (ETDEWEB)
Yusan, Sabriye; Aslani, Mahmut A.A.; Aytas, Sule [Ege Univ., Izmir (Turkey). Inst. of Nuclear Sciences; Bampaiti, Anastasia; Noli, Fotini [Aristotle University of Thessaloniki (Greece). Dept. of Chemistry; Erenturk, Sema [Istanbul Technical Univ., Ayazaga Campus, Maslak-Istanbul (Turkey). Energy Inst.
2016-11-01
In this study, for the first time ZnO nanoparticles and diatomite-supported ZnO nanocomposite have been utilized as adsorbent for the removal of Th(IV) ions from aqueous solutions under different experimental conditions. The Langmuir, Freundlich, Temkin and Dubinin- Radushkevich (D-R) isotherms were used to analyze the equilibrium data. The sorption equilibrium data were fitted well to the Langmuir isotherm with maximum sorption capacities values was found to be 1.105 mmol/g and 0.320 mmol/g for ZnO nanoparticles and diatomite supported ZnO nanocomposite, respectively. Pseudo-first and pseudo-second order equations, Intraparticle diffusion and Bangham's models were considered to evaluate the rate parameters and sorption mechanism. Sorption kinetics were better reproduced by the pseudo-second order model (R{sup 2} > 0.999), with an activation energy (E{sub a}) of +99.74 kJ/mol and +62.95 kJ/mol for ZnO nanoparticles and diatomite-supported ZnO nanocomposite, respectively. In order to specify the type of sorption reaction, thermodynamic parameters were also determined. The evaluated ΔG* and ΔH* indicate the non-spontaneous and endothermic nature of the reactions. The results of this work suggest that both of the used materials are fast and effective adsorbents for removing Th(IV) from aqueous solutions and chemical sorption plays a role in controlling the sorption rate.
Zhang, Xiaotao; Hao, Yinan; Wang, Ximing; Chen, Zhangjing
2017-04-01
Xanthoceras Sorbifolia Bunge hull activated carbon (XSA) was prepared and characterized by Brunauer-Emmett-Teller analysis, scanning electron microscopy and energy dispersive X-ray (EDX) spectroscopy. The ability of XSA as an adsorbent was investigated for the removal of the iron group ions Fe(III), Co(II), and Ni(II) from aqueous solution. Optimum adsorption parameters were determined based on the initial concentrations of the iron group ions, pH, adsorption temperature, and adsorption time in adsorption studies. The maximum monolayer adsorption capacities were 241.13 mg/g for Fe(III), 126.05 mg/g for Co(II), and 187.96 mg/g for Ni(II), respectively. Adsorption kinetics and isotherms showed that the adsorption process best fitted the nonlinear pseudo-second-order and Langmuir models, and the affinity of the ions for XSA decreased as follows: Fe(III) > Ni(II) > Co(II). Regeneration studies indicated that XSA could be used after several consecutive adsorption/desorption cycles using HNO3. Fourier transform infrared and EDX spectra revealed the chemical adsorption value of XSA as an adsorbent for removing iron group ions from aqueous solutions.
Huang, Limao; Liu, Jingyong; He, Yao; Sun, Shuiyu; Chen, Jiacong; Sun, Jian; Chang, KenLin; Kuo, Jiahong; Ning, Xun'an
2016-10-01
Thermodynamics and kinetics of sewage sludge (SS) and water hyacinth (WH) co-combustion as a blend fuel (SW) for bioenergy production were studied through thermogravimetric analysis. In CO2/O2 atmosphere, the combustion performance of SS added with 10-40wt.% WH was improved 1-1.97 times as revealed by the comprehensive combustion characteristic index (CCI). The conversion of SW in different atmospheres was identified and their thermodynamic parameters (ΔH,ΔS,ΔG) were obtained. As the oxygen concentration increased from 20% to 70%, the ignition temperature of SW decreased from 243.1°C to 240.3°C, and the maximum weight loss rate and CCI increased from 5.70%·min(-1) to 7.26%·min(-1) and from 4.913%(2)·K(-3)·min(-2) to 6.327%(2)·K(-3)·min(-2), respectively, which corresponded to the variation in ΔS and ΔG. The lowest activation energy (Ea) of SW was obtained in CO2/O2=7/3 atmosphere. Copyright © 2016 Elsevier Ltd. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Gamlin, C.D.; Dutta, N.K.; Roy Choudhury, N.; Matisons, J. [Ian Wark Research Institute, University of South Australia, SA 5095 Mawson Lakes (Australia); Kehoe, D. [Castrol Australia Pty. Ltd., NSW 2161 Guildford (Australia)
2002-09-15
Multigrade engine oils used in today's sophisticated engines are carefully engineered products. Different ingredients, such as viscosity index improvers, dispersants, antioxidants, detergents, antiwear agents, pour point depressants, etc. are added to the base oils to improve their performance as lubricants, significantly. However, the ultimate performance of the lubricant principally depends on the quality of the base oil. Therefore, understanding the degradation behaviour of the base oil is of significant importance. In this study, the kinetic parameters of the decomposition of different types and grades of base oils (all-natural, fully synthetic and semi-synthetic) have been investigated in detail by conventional and isothermal thermogravimetric analyses (TGA) as well as modulated TGA (MTGA{sup registered}). Pressure DSC (PDSC) has been employed to evaluate the spontaneous ignition and oxidative degradation behaviour of the base oils. Base oils with higher viscosity within the same grade tend to degrade at higher temperatures. It appears that the degradation of the oils studied can be modelled by an nth-order mechanism and have similar activation energies of degradation under an inert atmosphere. The all-natural base oil ALOR100 is more resistant to oxidation than the semi-synthetic Yubase4 and fully synthetic PAO4 due to the presence of naturally occurring antioxidants.
Morozova, E A; Kulikova, V V; Yashin, D V; Anufrieva, N V; Anisimova, N Y; Revtovich, S V; Kotlov, M I; Belyi, Y F; Pokrovsky, V S; Demidkina, T V
2013-07-01
The steady-state kinetic parameters of pyridoxal 5'-phosphate-dependent recombinant methionine γ -lyase from three pathogenic bacteria, Clostridium tetani, Clostridium sporogenes, and Porphyromonas gingivalis, were determined in β- and γ-elimination reactions. The enzyme from C. sporogenes is characterized by the highest catalytic efficiency in the γ-elimination reaction of L-methionine. It was demonstrated that the enzyme from these three sources exists as a tetramer. The N-terminal poly-histidine fragment of three recombinant enzymes influences their catalytic activity and facilitates the aggregation of monomers to yield dimeric forms under denaturing conditions. The cytotoxicity of methionine γ-lyase from C. sporogenes and C. tetani in comparison with Citrobacter freundii was evaluated using K562, PC-3, LnCap, MCF7, SKOV-3, and L5178y tumor cell lines. K562 (IC50=0.4-1.3 U/ml), PC-3 (IC50=0.1-0.4 U/ml), and MCF7 (IC50=0.04-3.2 U/ml) turned out to be the most sensitive cell lines.
Tseng, Jo-Ming; Lin, Chun-Ping; Huang, Sheng-Tien; Hsu, Johnson
2011-09-15
Over the past 30 years, the field of thermal analysis of organic peroxides has become an important issue in chemical engineering departments, safety departments, and in companies working with polymerization, petrifaction process, and so on. The contributions of thermal analysis to the evaluation and prediction of the runaway reactions have been important for decreasing or preventing a hazard, such as fire or explosion accident. This study was carried out using differential scanning calorimetry (DSC) to evaluate the kinetic and safety parameters in isothermal and non-isothermal conditions, for instance, temperature of no return (T(NR)), self accelerating decomposition temperature (SADT), time to maximum rate (TMR), activation energy (E(a)), frequency factor (A), reaction order (n), and reaction heat (ΔH), in terms of the hazardous material of 1,1,-di-(tert-butylperoxy)-3,3,5-trimethylcyclohexane (TMCH) 88 mass%. On the basis of this study, we demonstrated that TMCH 88 mass% must be well controlled in the manufacturing process due to the unstable structure of O-O, which releases a great quantity of heat, higher than 1300 J/g under decomposition. Results of this study could contribute to the relevant plants adopting TMCH 88mass% in a process, in order to prevent a fire or explosion accident from happening. Copyright © 2011 Elsevier B.V. All rights reserved.
Salwiński, Aleksander; Delépée, Raphaël; Maunit, Benoît
2011-12-15
A mass spectrometry (MS)-based methodology for enzymatic assay in equilibrium conditions was designed and evaluated. This on-line assay involves the introduction of a continuous-flow step gradient (CFSG) of a substrate solution in the column containing immobilized enzyme and the simultaneous tracking of the product formation. We showed that the constant concentration of substrate in the entire bioreactor for an appropriate duration ensures the equilibration of the studied enzyme (mushroom tyrosinase). Under these conditions, it was demonstrated also that the kinetic and enzymatic parameters (Michaelis-Menten constant, K(M) , the maximal specific activity, SA(max)) are independent of the flow rate of the mobile phase. The feasibility of the mentioned approach for inhibitory tests was also investigated. The coupling of the mass spectrometer to the bio-reactor allows the selective monitoring of the enzymatic reaction products and increases their detection level. Very high sensitivity, 500 pmol/min/column, and selective monitoring of the products of the enzymatic reaction are allowed by MS detection. The methodology developed here constitutes a sensitive analytical tool to study enzymes requiring long equilibration times. Copyright © 2011 John Wiley & Sons, Ltd.
Magleby, K L; Weiss, D S
1990-12-01
Analysis of currents recorded from single channels is complicated by the limited time resolution (filtering) of the data which can prevent the detection of brief intervals. Although a number of approaches have been used to correct for the undetected intervals (missed events) when identifying kinetic models and estimating parameters, none of them provide a general method which takes into account the true effects of noise and limited time resolution. This paper presents such a method. The approach is to use simulated single-channel currents to incorporate the true effects of filtering and noise on missed events and interval durations. The simulated currents are then analyzed in a manner identical to that used to analyze the experimental currents. An iterative search process using likelihood comparison of two-dimensional dwell-time distributions obtained from the simulated and experimental single-channel currents then allows the most likely rate constants to be determined. The large errors and false solutions that can result from the more typically applied assumptions of no noise and an absolute dead time (idealized filtering) are excluded by the iterative simulation method, and the correlation information contained in the two-dimensional distributions should increase the ability to distinguish among different gating mechanisms. The iterative simulation method is generally applicable to channels which typically open to a single conductance level. For these channels the method places no restrictions on the proposed gating mechanism or the form of the predicted dwell-time distributions.
Energy Technology Data Exchange (ETDEWEB)
Eoh, Jae Hyuk; Sim, Yoon Sub; Kim, Seong O
2004-01-01
The conceptual design of a sodium cooled liquid metal reactor, KALIMER (Korea Advanced LIquid MEtal Reactor) of which electric power is 150 MWe, has performed. A revised design concept up-rating electric capacity to 600 MWe, named as KALIMER-600, has been currently developed. The Residual Heat Removal (RHR) system under a loss of normal heat sink accident of KALIMER-600 is characterized by the concept of PDRC (Passive Decay heat Removal Circuit) and it has superiority in the aspect that an enough decay heat removal capacity can be provided and any additional consideration associated with the core thermal power increase can also be neglected since it uses a very simple concept of direct reactor pool cooling. In this regard, a proper method for setting up the steady state design parameters at the design point of PDRC system should be required to secure a sufficient decay heat removal capacity of the RHR system in KALIMER-600. This study describes developing procedure of two different methods for determining the design parameters of PDRC system. They are the rough and the detail analysis method, and the methods have a mutual complementary nature. On the basis of the relationship between the various design parameters produced by using the developed methods, overall characteristics of PDRC system corresponding to the variations of system design parameters have been investigated, and more detail calculations are carried out using the results of the investigations such as the variations of the temperature, pressure loss, mass flowrate and UA values in each heat transfer circuit or heat exchanger in PDRC system. This report also provides the brief procedure of a computational programming for the detail analysis method and, using the computational routine, it is expected that an expansion of applicability to flexibly cope with a design change of PDRC system in KALIMER-600 is possible.
Learning Chemical Kinetics with Spreadsheets.
Blickensderfer, Roger
1990-01-01
Presented are several simple kinetic systems together with the spreadsheets used to solve them. A set of exercises in chemical kinetics appropriate for an introductory course in physical chemistry is given. Error propagation calculations with experimental data are illustrated. (CW)
Energy Technology Data Exchange (ETDEWEB)
Reynolds, J. M.; Lopez-Bruna, D.
2009-12-11
This report is the third of a series [Informes Tecnicos Ciemat 1165 y 1172] devoted to the development of a new numerical code to solve the guiding center equation for electrons and ions in toroidal plasmas. Two calculation meshes corresponding to axisymmetric tokamaks are now prepared and the kinetic equation is expanded so the standard terms of neoclassical theory --fi rst order terms in the Larmor radius expansion-- can be identified, restricting the calculations correspondingly. Using model density and temperature profiles for the plasma, several convergence test are performed depending on the calculation meshes and the expansions of the distribution function; then the results are compared with the theory [Hinton and Hazeltine, Rev. Mod. Phys. (1976)]. (Author) 18 refs.
Smiljanić, J.; Žeželj, M.; Milanović, V.; Radovanović, J.; Stanković, I.
2014-03-01
A strong magnetic field applied along the growth direction of a quantum cascade laser (QCL) active region gives rise to a spectrum of discrete energy states, the Landau levels. By combining quantum engineering of a QCL with a static magnetic field, we can selectively inhibit/enhance non-radiative electron relaxation process between the relevant Landau levels of a triple quantum well and realize a tunable surface emitting device. An efficient numerical algorithm implementation is presented of optimization of GaAs/AlGaAs QCL region parameters and calculation of output properties in the magnetic field. Both theoretical analysis and MATLAB implementation are given for LO-phonon and interface roughness scattering mechanisms on the operation of QCL. At elevated temperatures, electrons in the relevant laser states absorb/emit more LO-phonons which results in reduction of the optical gain. The decrease in the optical gain is moderated by the occurrence of interface roughness scattering, which remains unchanged with increasing temperature. Using the calculated scattering rates as input data, rate equations can be solved and population inversion and the optical gain obtained. Incorporation of the interface roughness scattering mechanism into the model did not create new resonant peaks of the optical gain. However, it resulted in shifting the existing peaks positions and overall reduction of the optical gain. Catalogue identifier: AERL_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AERL_v1_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 37763 No. of bytes in distributed program, including test data, etc.: 2757956 Distribution format: tar.gz Programming language: MATLAB. Computer: Any capable of running MATLAB version R2010a or higher. Operating system: Any platform
Moore-Russo, Deborah A.; Cortes-Figueroa, Jose E.; Schuman, Michael J.
2006-01-01
The use of Calculator-Based Laboratory (CBL) technology, the graphing calculator, and the cooling and heating of water to model the behavior of consecutive first-order reactions is presented, where B is the reactant, I is the intermediate, and P is the product for an in-class demonstration. The activity demonstrates the spontaneous and consecutive…
Directory of Open Access Journals (Sweden)
Ioana Dana Pandur
2012-05-01
Full Text Available Oxitocyn has been used to improve reproductive performance in swine, especially farrowing rate and litter size. The objective of this study was to investigated whether the main reproduction parameters calculated for sows improves when Oxytocin (Oxitocyn®; 10 U.I./ml was added to diluted semen. The scope of this experiment was to test the efficiency of adding oxitocyn in the diluted semen tubes over the main reproduction parameters (fecundity rate, gestation rate, farrowing rate and litter size for Large White sows. Sows from one large production unit were artificially inseminated; semen was either enriched with oxitocyn (group 1, n=315, either untreated (group 2, n=351. Fecundity rate, gestation rate, farrowing rate and litter size were recorded. After adding 0.4 ml oxitocyn to diluted semen right before artificial insemination of Large White sows, fecundity rate was 80.95%, while the group inseminated with untreated semen had a fecundity rate of 74.93%, the difference being statically uninsured. Regarding the gestation rate, for the experimental group was 78.10%, while for the control group was 70.09%, this difference being significant (p<0.05. The farrowing rate calculated for the experimental group was 76.19%, while for the control group was 68.95 %, this difference being also significant (p<0.05. Litter size was 13.36 piglets/sow for the experimental group, with 1.18 piglets/sow higher than for the control group (12.18 piglets/sow, this difference being very significant (p<0.001.
Energy Technology Data Exchange (ETDEWEB)
Marie, S. [CEA Saclay, DEN/DM2S/SEMT/LISN, 91191 Gif sur Yvette Cedex (France)], E-mail: stephane.marie@cea.fr; Chapuliot, S.; Kayser, Y. [CEA Saclay, DEN/DM2S/SEMT/LISN, 91191 Gif sur Yvette Cedex (France); Lacire, M.H. [CEA Saclay, DEN/DDIN, 91191 Gif sur Yvette Cedex (France); Drubay, B. [CEA Saclay, DEN/DM2S/SEMT/LISN, 91191 Gif sur Yvette Cedex (France); Barthelet, B. [EDF/EPN, Site Cap Ampere, 1 place Pleyel 93207, Saint Denis Cedex 1 (France); Le Delliou, P. [EDF Pole Industrie-Division R and D, Site des Renardieres, Route de Sens, Ecuelles, 77250 Moret sur Loing Cedex (France); Rougier, V. [EDF/UTO SIS/GAM, 6, avenue Montaigne, 93192 Noisy le Grand (France); Naudin, C. [EDF/SEPTEN, 12-14, avenue Dutrievoz, 69628 Villeurbanne Cedex (France); Gilles, P.; Triay, M. [AREVA ANP, Tour AREVA, 92084 Paris La Defense Cedex 16 (France)
2007-10-15
French nuclear codes include flaw assessment procedures: the RSE-M Code 'Rules for In-service Inspection of Nuclear Power Plant Components' and the RCC-MR code 'Design and Construction rules for mechanical components of FBR nuclear islands and high temperature applications'. An important effort of development of these analytical methods has been made for the last 10 years in the frame of a collaboration between CEA, EDF and AREVA-NP, and in the frame of R and D actions involving CEA and IRSN. These activities have led to a unification of the common methods of the two codes. The calculation of fracture mechanics parameters, and in particular the stress intensity factor K{sub I} and the J integral, has been widely developed for industrial configurations. All the developments have been integrated in the 2005 edition of RSE-M and in the 2007 edition of RCC-MR. This series of articles is composed of 5 parts: the first part presents an overview of the methods proposed in the RCC-MR and RSE-M codes. Parts II-IV provide compendia for specific components. The geometries are plates (part II), pipes (part III) and elbows (part IV). Finally, part V presents the validation elements of the methods, with details on the process followed for the development and evaluation of the accuracy of the proposed analytical methods. This second article in the series presents all details for the stress intensity factor and J calculations for cracked plates. General data applicable for all defect geometries are first presented, and then, available defect geometries where compendia for K{sub I} and {sigma}{sub ref} calculation are provided are given.
Energy Technology Data Exchange (ETDEWEB)
Marie, S. [CEA Saclay, DEN/DM2S/SEMT/LISN, 91191 Gif sur Yvette Cedex (France)], E-mail: stephane.marie@cea.fr; Chapuliot, S.; Kayser, Y. [CEA Saclay, DEN/DM2S/SEMT/LISN, 91191 Gif sur Yvette Cedex (France); Lacire, M.H. [CEA Saclay, DEN/DDIN, 91191 Gif sur Yvette Cedex (France); Drubay, B. [CEA Saclay, DEN/DM2S/SEMT/LISN, 91191 Gif sur Yvette Cedex (France); Barthelet, B. [EDF/EPN, Site Cap Ampere, 1 place Pleyel 93207, Saint Denis Cedex 1 (France); Le Delliou, P. [EDF Pole Industrie-Division R and D, Site des Renardieres, Route de Sens, Ecuelles, 77250 Moret sur Loing Cedex (France); Rougier, V. [EDF/UTO SIS/GAM, 6, avenue Montaigne, 93192 Noisy le Grand (France); Naudin, C. [EDF/SEPTEN, 12-14, Avenue Dutrievoz, 69628 Villeurbanne Cedex (France); Gilles, P.; Triay, M. [AREVA ANP, Tour AREVA, 92084 Paris La Defense Cedex 16 (France)
2007-10-15
French nuclear codes include flaw assessment procedures: the RSE-M Code 'Rules for In-service Inspection of Nuclear Power Plant Components' and the RCC-MR code 'Design and Construction rules for mechanical components of FBR nuclear islands and high-temperature applications'. An important effort of development of these analytical methods has been made for the last 10 years in the frame of collaboration between CEA, EDF and AREVA-NP, and in the frame of R and D actions involving CEA and IRSN. These activities have led to a unification of the common methods of the two codes. The calculation of fracture mechanics parameters, and in particular the stress-intensity factor K{sub I} and the J integral, has been widely developed for industrial configurations. All the developments have been integrated in the 2005 edition of the RSE-M and in the 2007 edition of the RCC-MR. This series of articles is composed of 5 parts: the first part presents an overview of the methods proposed in the RCC-MR and RSE-M codes. Parts II-IV provide compendia for specific components. The geometries are plates (part II), pipes (part III) and elbows (part IV). Part V presents validation, with details on the accuracy of the proposed analytical method. This third part in the series presents details of the stress intensity factor and J calculations for cracked pipes. General data applicable for all defect geometries are first presented, and then, compendia for K{sub I} and {sigma}{sub ref} calculations are provided for specific cases.
Directory of Open Access Journals (Sweden)
Boris Fomin
2012-10-01
Full Text Available This paper presents a new version of radiative transfer model called the Fast Line-by-Line Model (FLBLM, which is based on the Line-by-Line (LbL and Monte Carlo (MC methods and rigorously treats particulate and molecular scattering alongside absorption. The advantage of this model consists in the use of the line-by-line model that allows for the computing of high-resolution spectra quite quickly. We have developed the model by taking into account the polarization state of light and carried out some validations by comparison against benchmark results. FLBLM calculates the Stokes parameters spectra of shortwave radiation in vertically inhomogeneous atmospheres. This update makes the model applicable for the assessment of cloud and aerosol influence on radiances as measured by the SW high-resolution polarization spectrometers. In sample results we demonstrate that the high-resolution spectra of the Stokes parameters contain more detailed information about clouds and aerosols than the medium- and low-resolution spectra wherein lines are not resolved. The presented model is rapid enough for many practical applications (e.g., validations and might be useful especially for the remote sensing. FLBLM is suitable for development of the reliable technique for retrieval of optical and microphysical properties of clouds and aerosols from high-resolution satellites data.
Ramalingam, Chidambaram
2015-01-01
This study is focused on the possible use of Ceratocystis paradoxa MSR2 native biomass for Cr(VI) biosorption. The influence of experimental parameters such as initial pH, temperature, biomass dosage, initial Cr(VI) concentration and contact time were optimized using batch systems as well as response surface methodology (RSM). Maximum Cr(VI) removal of 68.72% was achieved, at an optimal condition of biomass dosage 2g L−1, initial Cr(VI) concentration of 62.5 mg L−1 and contact time of 60 min. The closeness of the experimental and the predicted values exhibit the success of RSM. The biosorption mechanism of MSR2 biosorbent was well described by Langmuir isotherm and a pseudo second order kinetic model, with a high regression coefficient. The thermodynamic study also revealed the spontaneity and exothermic nature of the process. The surface characterization using FT-IR analysis revealed the involvement of amine, carbonyl and carboxyl groups in the biosorption process. Additionally, desorption efficiency of 92% was found with 0.1 M HNO3. The Cr(VI) removal efficiency, increased with increase in metal ion concentration, biomass concentration, temperature but with a decrease in pH. The size of the MSR2 biosorbent material was found to be 80 μm using particle size analyzer. Atomic force microscopy (AFM) visualizes the distribution of Cr(VI) on the biosorbent binding sites with alterations in the MSR2 surface structure. The SEM-EDAX analysis was also used to evaluate the binding characteristics of MSR2 strain with Cr(VI) metals. The mechanism of Cr(VI) removal of MSR2 biomass has also been proposed. PMID:25822726
Melhus, Christopher S; Rivard, Mark J
2006-06-01
Underlying characteristics in brachytherapy dosimetry parameters for medical radionuclides 137Cs, 125I, 192Ir, 103Pd, and 169Yb were examined using Monte Carlo methods. Sources were modeled as unencapsulated point or line sources in liquid water to negate variations due to materials and construction. Importance of phantom size, mode of radiation transport physics--i.e., photon transport only or coupled photon:electron transport, phantom material, volume averaging, and Monte Carlo tally type were studied. For noninfinite media, g(r) was found to degrade as r approached R, the phantom radius. MCNP5 results were in agreement with those published using GEANT4. Brachytherapy dosimetry parameters calculated using coupled photon:electron radiation transport simulations did not differ significantly from those using photon transport only. Dose distributions from low-energy photon-emitting radionuclides 125I and 103Pd were sensitive to phantom material by upto a factor of 1.4 and 2.0, respectively, between tissue-equivalent materials and water at r =9 cm. In comparison, high-energy photons from 137Cs, 192Ir, and 169Yb demonstrated +/- 5% differences in dose distributions between water and tissue substitutes at r=20 cm. Similarly, volume-averaging effects were found to be more significant for low-energy radionuclides. When modeling line sources with L F4 track-length estimators were employed to determine brachytherapy dosimetry parameters. F6 was found to be necessary for g(r), while both tallies provided equivalent results for F(r, theta).
DEFF Research Database (Denmark)
Sales-Cruz, Mauricio; Heitzig, Martina; Cameron, Ian
2011-01-01
In this chapter the importance of parameter estimation in model development is illustrated through various applications related to reaction systems. In particular, rate constants in a reaction system are obtained through parameter estimation methods. These approaches often require the application...... of optimisation techniques coupled with dynamic solution of the underlying model. Linear and nonlinear approaches to parameter estimation are investigated. There is also the application of maximum likelihood principles in the estimation of parameters, as well as the use of orthogonal collocation to generate a set...... of algebraic equations as the basis for parameter estimation.These approaches are illustrated using estimations of kinetic constants from reaction system models....
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Perez Manes, Jorge
2013-02-26
This dissertation contributes to the development of high-fidelity coupled neutron kinetic and thermal hydraulic simulation tools with high resolution of the spatial discretization of the involved domains for the analysis of Light Water Reactors transient scenarios.
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Anspaugh, L. R.; Napier, Bruce A.
2009-10-23
This brief report documents the selection of parameters needed to support individual-dose calculations from 131I released into the environment with gaseous effluents from the Mayak Production Association.
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Rodriguez, M.
1997-07-01
The treatment for some thyroid carcinomas involves surgically removing the thyroid gland and administering the radiopharmaceutical Sodium iodide-{sup 131}I (NaI). A diagnostic dose of NaI is given to the patient to determine if remnant tissue from the gland remains or larger doses are administered in order to treat the malignant tissue. Past research regarding NaI uptake and retention in euthyroid individuals (normal functioning thyroid) reveal that radioiodine concentrates mainly in the thyroid tissue and the remaining material is excreted from the body. The majority of radioiodine in athyroid (without thyroid) individuals is also eliminated from the body; however, there has been recent evidence of a long-term retention phase for individuals with no radioiodine concentrating tissue. The general purpose of this study was to develop a kinetic model and estimate the absorbed dose to athyroid individuals regarding the distribution and retention of NaI.
Sun, Yuzhen; Pan, Wenxiao; Lin, Yuan; Fu, Jianjie; Zhang, Aiqian
2016-01-01
Short-chain chlorinated paraffins (SCCPs) are still controversial candidates for inclusion in the Stockholm Convention. The inherent mixture nature of SCCPs makes it rather difficult to explore their environmental behaviors. A virtual molecule library of 42,720 C10-SCCP congeners covering the full structure spectrum was constructed. We explored the structural effects on the thermodynamic parameters and environmental degradability of C10-SCCPs through semi-empirical quantum chemical calculations. The thermodynamic properties were acquired using the AM1 method, and frontier molecular orbital analysis was carried out to obtain the E(HOMO), E(LUMO) and E(LUMO)-E(HOMO) for degradability exploration at the same level. The influence of the chlorination degree (N(Cl)) on the relative stability and environmental degradation was elucidated. A novel structural descriptor, μ, was proposed to measure the dispersion of the chlorine atoms within a molecule. There were significant correlations between thermodynamic values and N(Cl), while the reported N(Cl)-dependent pollution profile of C10-SCCPs in environmental samples was basically consistent with the predicted order of formation stability of C10-SCCP congeners. In addition, isomers with large μ showed higher relative stability than those with small μ. This could be further verified by the relationship between μ and the reactivity of nucleophilic substitution and OH attack respectively. The C10-SCCP congeners with less Cl substitution and lower dispersion degree are susceptible to environmental degradation via nucleophilic substitution and hydroxyl radical attack, while direct photolysis of C10-SCCP congeners cannot readily occur due to the large E(LUMO)-E(HOMO) values. The chlorination effect and the conclusions were further checked with appropriate density functional theory (DFT) calculations. Copyright © 2015. Published by Elsevier B.V.
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Marie, S. [CEA Saclay, DEN/DM2S/SEMT/LISN, 91191 Gif sur Yvette Cedex (France)], E-mail: stephane.marie@cea.fr; Chapuliot, S.; Kayser, Y. [CEA Saclay, DEN/DM2S/SEMT/LISN, 91191 Gif sur Yvette Cedex (France); Lacire, M.H. [CEA Saclay, DEN/DDIN, 91191 Gif sur Yvette Cedex (France); Drubay, B. [CEA Saclay, DEN/DM2S/SEMT/LISN, 91191 Gif sur Yvette Cedex (France); Barthelet, B. [EDF/EPN, Site Cap Ampere, 1 place Pleyel 93207, Saint Denis Cedex 1 (France); Le Delliou, P. [EDF Pole Industrie-Division R and D, Site des Renardieres, Route de Sens, Ecuelles, 77250 Moret sur Loing Cedex (France); Rougier, V. [EDF/UTO SIS/GAM, 6, avenue Montaigne, 93192 Noisy le Grand (France); Naudin, C. [EDF/SEPTEN, 12-14, avenue Dutrievoz, 69628 Villeurbanne Cedex (France); Gilles, P.; Triay, M. [AREVA ANP, Tour AREVA, 92084 Paris La Defense Cedex 16 (France)
2007-10-15
Two French nuclear codes include flaw assessment procedures: the RSE-M code 'Rules for In-service Inspection of Nuclear Power Plant Components' and the RCC-MR code 'Design and Construction rules for mechanical components of FBR nuclear islands and high temperature applications'. An important effort of development of these analytical methods has been made for the last 10 years in the frame of a collaboration between CEA, EDF and AREVA-NP, and in the frame of R and D actions involving CEA and IRSN. These activities have led to a unification of the common methods of the two codes. The calculation of fracture mechanics parameters, and in particular the stress intensity factor K{sub I} and the J integral, has been widely developed for industrial configurations. All developments have been integrated in the 2005 edition of RSE-M and in the 2007 edition of RCC-MR. This series of articles is composed of five parts: this first one presents an overview of the methods proposed in the RCC-MR and RSE-M codes. Parts II-IV provide compendia for specific components: plates (part II), pipes (part III) and elbows (part IV). Finally, part V presents the validation elements of the methods, with details on the process followed for their development and on evaluation of the accuracy of the proposed analytical methods. This first article of the series presents an overview of the calculation of K{sub I} and J in these two codes and describes briefly the defect assessment analyses. Specific details in the Appendix A16 of RCC-MR (LBB procedure and creep analyses) are also introduced in this article.
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Zhen, X; Chen, H; Liao, Y; Zhou, L [Southern Medical University, Guangzhou, Guangdong (China); Hrycushko, B; Albuquerque, K; Gu, X [UT Southwestern Medical Center, Dallas, TX (United States)
2016-06-15
Purpose: To study the feasibility of employing deformable registration methods for accurate rectum dose volume parameters calculation and their potentials in revealing rectum dose-toxicity between complication and non-complication cervical cancer patients with brachytherapy treatment. Method and Materials: Data from 60 patients treated with BT including planning images, treatment plans, and follow-up clinical exam were retrospectively collected. Among them, 12 patients complained about hematochezia were further examined with colonoscopy and scored as Grade 1–3 complication (CP). Meanwhile, another 12 non-complication (NCP) patients were selected as a reference group. To seek for potential gains in rectum toxicity prediction when fractional anatomical deformations are account for, the rectum dose volume parameters D0.1/1/2cc of the selected patients were retrospectively computed by three different approaches: the simple “worstcase scenario” (WS) addition method, an intensity-based deformable image registration (DIR) algorithm-Demons, and a more accurate, recent developed local topology preserved non-rigid point matching algorithm (TOP). Statistical significance of the differences between rectum doses of the CP group and the NCP group were tested by a two-tailed t-test and results were considered to be statistically significant if p < 0.05. Results: For the D0.1cc, no statistical differences are found between the CP and NCP group in all three methods. For the D1cc, dose difference is not detected by the WS method, however, statistical differences between the two groups are observed by both Demons and TOP, and more evident in TOP. For the D2cc, the CP and NCP cases are statistically significance of the difference for all three methods but more pronounced with TOP. Conclusion: In this study, we calculated the rectum D0.1/1/2cc by simple WS addition and two DIR methods and seek for gains in rectum toxicity prediction. The results favor the claim that accurate dose
Ghose, Arup K; Ott, Gregory R; Hudkins, Robert L
2017-01-18
At the discovery stage, it is important to understand the drug design concepts for a CNS drug compared to those for a non-CNS drug. Previously, we published on ideal CNS drug property space and defined in detail the physicochemical property distribution of CNS versus non-CNS oral drugs, the application of radar charting (a graphical representation of multiple physicochemical properties used during CNS lead optimization), and a recursive partition classification tree to differentiate between CNS- and non-CNS drugs. The objective of the present study was to further understand the differentiation of physicochemical properties between CNS and non-CNS oral drugs by the development and application of a new CNS scoring scheme: Technically Extended MultiParameter Optimization (TEMPO). In this multiparameter method, we identified eight key physicochemical properties critical for accurately assessing CNS druggability: (1) number of basic amines, (2) carbon-heteroatom (non-carbon, non-hydrogen) ratio, (3) number of aromatic rings, (4) number of chains, (5) number of rotatable bonds, (6) number of H-acceptors, (7) computed octanol/water partition coefficient (AlogP), and (8) number of nonconjugated C atoms in nonaromatic rings. Significant features of the CNS-TEMPO penalty score are the extension of the multiparameter approach to generate an accurate weight factor for each physicochemical property, the use of limits on both sides of the computed property space range during the penalty calculation, and the classification of CNS and non-CNS drug scores. CNS-TEMPO significantly outperformed CNS-MPO and the Schrödinger QikProp CNS parameter (QP_CNS) in evaluating CNS drugs and has been extensively applied in support of CNS lead optimization programs.
Vidal, E; Yokomi, R K; Moreno, A; Bertolini, E; Cambra, M
2012-01-01
Citrus tristeza virus (CTV) is one of the most important virus diseases that affect citrus. Control of CTV is achieved by grafting selected virus-free citrus scions onto CTV-tolerant or -resistant rootstocks. Quarantine and certification programs are essential for avoiding the entry and propagation of severe strains of CTV. Citrus nurseries in Spain and central California (United States) maintain zero-tolerance policies for CTV that require sensitive, specific, and reliable pathogen-detection methods. Tissue-print (TP) real-time reverse-transcriptase polymerase chain reaction (RT-PCR) assay was compared with the validated TP enzyme-linked immunosorbent assay (ELISA), using the CTV-specific monoclonal antibodies 3DF1 and 3CA5, for CTV detection. In total, 1,395 samples from healthy and CTV-infected nursery and mature tree plants were analyzed with both methods. The total agreement between both detection methods was substantial (Cohen's kappa index of 0.77 ± 0.03). The diagnostic parameters of each technique (i.e., the sensitivity, specificity, and likelihood ratios) were evaluated in a second test involving 658 Citrus macrophylla nursery plants. Mexican lime indexing was used to evaluate samples with discrepant results in the analysis. For TP-ELISA, a sensitivity of 0.8015, a specificity of 0.9963, and a positive and negative likelihood ratio of 216.42 and 0.199, respectively, were estimated. For TP real-time RT-PCR, a sensitivity of 0.9820, a specificity of 0.8519, and a positive and negative likelihood ratio of 6.63 and 0.021, respectively, were estimated. These diagnostic parameters show that TP real-time RT-PCR was the most sensitive technique, whereas TP-ELISA showed the highest specificity, validating the use of the molecular technique for routine CTV-detection purposes. In addition, our results show that the combination of both techniques can accurately substitute for the conventional biological Mexican lime index for the detection of CTV. The calculation of
Fatima, Bilqees; Ali, Sikander
2012-01-01
Sixteen different mould cultures viz. Aspergillus, Alternaria, Arthroderma, Trichoderma, Fusarium, Penicillium, Rhizopus and Chochliobolus were isolated from the soil samples of Qatar by serial dilution method. The preliminary screening of isolates was done by selecting initial colonies showing relatively bigger zones of starch hydrolysis on nutrient agar plates. The isolates were then subjected to secondary screening by submerged fermentation (SmF). The 1,4-α-D-glucan glucohydrolase (GGH) activity ranged from 1.906-12.675 U/ml/min. The product yield was analysed in dependence of mycelial morphology, biomass level and protein content. The isolate Aspergillus oryzae llB-6 which gave maximum enzyme production was incubated in M3 medium containing 20 g/l starch, 10 g/l lactose, 8.5 g/l yeast extract, 6 g/l corn steep liquor (CSL), 1.2 g/l MgSO4.7H2O, 1.3 g/l NH4Cl, 0.6 g/l CaCl2.2H2O, pH 5 at 30±2°C and 200 rpm. On the basis of kinetic variables, notably Qp (0.058±0.01(a) U/g/h), Yp/s (0.308±0.03(ab) U/g) and qp (0.210±0.032(abc) U/g fungal biomass/h), A. oryzae IIB-6 was found to be a hyper producer of GGH (LSD 0.0345) compared to A. kawachii IIB-2. A noticeable enhancement in enzyme activity of over 30% was observed (13.917±1.01 U/ml/min) when the process parameters viz. cultural conditions (pH 5, incubation period 72 h) and nutritional requirements (6 g/l CSL, 9.5 g/l yeast extract, 10 g/l starch, 20 g/l lactose) were further optimized using a 2-factorial Plackett-Burman design. The model terms were found to be highly significant (HS, p≤0.05), indicating the potential utility of the culture (dof~3).
A comparative study of kinetics of nuclear reactors
Directory of Open Access Journals (Sweden)
Obaidurrahman Khalilurrahman
2009-01-01
Full Text Available The paper deals with the study of reactivity initiated transients to investigate major differences in the kinetics behavior of various reactor systems under different operating conditions. The article also states guidelines to determine the safety limits on reactivity insertion rates. Three systems, light water reactors (pressurized water reactors, heavy water reactors (pressurized heavy water reactors, and fast breeder reactors are considered for the sake of analysis. The upper safe limits for reactivity insertion rate in these reactor systems are determined. The analyses of transients are performed by a point kinetics computer code, PKOK. A simple but accurate method for accounting total reactivity feedback in kinetics calculations is suggested and used. Parameters governing the kinetics behavior of the core are studied under different core states. A few guidelines are discussed to project the possible kinetics trends in the next generation reactors.
Adsorption kinetics of methyl violet onto perlite.
Doğan, Mehmet; Alkan, Mahir
2003-01-01
This study examines adsorption kinetics and activation parameters of methyl violet on perlite. The effect of process parameters like contact time, concentration of dye, temperature and pH on the extent of methyl violet adsorption from solution has been investigated. Results of the kinetic studies show that the adsorption reaction is first order with respect to dye solution concentration with activation energy of 13.2 kJ mol(-1). This low activation energy value indicates that the adsorption reaction is diffusion controlled. The activation parameters using Arrhenius and Eyring equations have been calculated. Adsorption increases with increase of variables such as contact time, initial dye concentration, temperature and pH.
Predoi-Cross, A.; Malathy Devi, V.; Sutradhar, P.; Sinyakova, T.; Buldyreva, J.; Sung, K.; Smith, M. A. H.; Mantz, A. W.
2016-07-01
This paper presents the results of a spectroscopic line shape study of self- and nitrogen-broadened 12CH3D transitions in the ν3 and ν5 bands in the Triad region. We combined five pure gas spectra with eighteen spectra of lean mixtures of 12CH3D and nitrogen, all recorded with a Bruker IFS-125 HR Fourier transform spectrometer. The spectra have been analyzed simultaneously using a multispectrum nonlinear least squares fitting technique. N2-broadened line parameters for 184 transitions in the ν3 band and 205 transitions in the ν5 band were measured. In addition, line positions and line intensities were measured for 168 transitions in the ν3 band and 214 transitions in the ν5 band. We have observed 10 instances of weak line mixing corresponding to K″=3 A1 or A2 transitions. Comparisons were made for the N2-broadening coefficients and associated temperature exponents with corresponding values calculated using a semi-classical Robert Bonamy type formalism that involved an inter-molecular potential with terms corresponding to short- and long-range interactions, and exact classical molecular trajectories. The theoretical N2-broadened coefficients are overestimated for high J values, but are in good agreement with the experimental values for small and middle range J values.
Garcia, F.; Mesa, J.; Arruda-Neto, J. D. T.; Helene, O.; Vanin, V.; Milian, F.; Deppman, A.; Rodrigues, T. E.; Rodriguez, O.
2007-03-01
The code STATFLUX, implementing a new and simple statistical procedure for the calculation of transfer coefficients in radionuclide transport to animals and plants, is proposed. The method is based on the general multiple-compartment model, which uses a system of linear equations involving geometrical volume considerations. Flow parameters were estimated by employing two different least-squares procedures: Derivative and Gauss-Marquardt methods, with the available experimental data of radionuclide concentrations as the input functions of time. The solution of the inverse problem, which relates a given set of flow parameter with the time evolution of concentration functions, is achieved via a Monte Carlo simulation procedure. Program summaryTitle of program:STATFLUX Catalogue identifier:ADYS_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADYS_v1_0 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions: none Computer for which the program is designed and others on which it has been tested:Micro-computer with Intel Pentium III, 3.0 GHz Installation:Laboratory of Linear Accelerator, Department of Experimental Physics, University of São Paulo, Brazil Operating system:Windows 2000 and Windows XP Programming language used:Fortran-77 as implemented in Microsoft Fortran 4.0. NOTE: Microsoft Fortran includes non-standard features which are used in this program. Standard Fortran compilers such as, g77, f77, ifort and NAG95, are not able to compile the code and therefore it has not been possible for the CPC Program Library to test the program. Memory required to execute with typical data:8 Mbytes of RAM memory and 100 MB of Hard disk memory No. of bits in a word:16 No. of lines in distributed program, including test data, etc.:6912 No. of bytes in distributed program, including test data, etc.:229 541 Distribution format:tar.gz Nature of the physical problem:The investigation of transport mechanisms for
Energy Technology Data Exchange (ETDEWEB)
Marie, S. [CEA Saclay, DEN/DM2S/SEMT/LISN, 91191 Gif sur Yvette Cedex (France)], E-mail: stephane.marie@cea.fr; Chapuliot, S.; Kayser, Y. [CEA Saclay, DEN/DM2S/SEMT/LISN, 91191 Gif sur Yvette Cedex (France); Lacire, M.H. [CEA Saclay, DEN/DDIN, 91191 Gif sur Yvette Cedex (France); Drubay, B. [CEA Saclay, DEN/DM2S/SEMT/LISN, 91191 Gif sur Yvette Cedex (France); Barthelet, B. [EDF/EPN, Site Cap Ampere, 1 place Pleyel 93207, Saint Denis Cedex 1 (France); Le Delliou, P. [EDF Pole Industrie-Division R and D, Site des Renardieres, Route de Sens, Ecuelles, 77250 Moret sur Loing Cedex (France); Rougier, V. [EDF/UTO, SIS/GAM, 6, avenue Montaigne, 93192 Noisy le Grand (France); Naudin, C. [EDF/SEPTEN, 12-14, avenue Dutrievoz, 69628 Villeurbanne Cedex (France); Gilles, P.; Triay, M. [AREVA ANP, Tour AREVA, 92084 Paris La Defense Cedex 16 (France)
2007-10-15
French nuclear codes include flaw assessment procedures: the RSE-M Code 'Rules for In-service Inspection of Nuclear Power Plant Components' and the RCC-MR code 'Design and Construction Rules for Mechanical Components of FBR Nuclear Islands and High Temperature Applications'. Development of analytical methods has been made for the last 10 years in the framework of a collaboration between CEA, EDF and AREVA-NP, and by R and D actions involving CEA and IRSN. These activities have led to a unification of the common methods of the two codes. The calculation of fracture mechanics parameters, in particular the stress intensity factor K{sub I} and the J integral, has been widely developed for industrial configurations. All the developments have been integrated in the 2005 edition of RSE-M and in 2007 edition of RCC-MR. This series of articles consists of 5 parts: the first part presents an overview of the methods proposed in the RCC-MR and RSE-M codes. Parts II-IV provide the compendia for specific components. The geometries are plates (part II), pipes (part III) and elbows (part IV). This part presents validation of the methods, with details on the process followed for their development and of the evaluation accuracy of the proposed analytical methods.
Ito, Hiroshi; Ikoma, Yoko; Seki, Chie; Kimura, Yasuyuki; Kawaguchi, Hiroshi; Takuwa, Hiroyuki; Ichise, Masanori; Suhara, Tetsuya; Kanno, Iwao
2017-05-01
Objectives In PET studies for neuroreceptors, tracer kinetics are described by the two-tissue compartment model (2-TCM), and binding parameters, including the total distribution volume (V T ), non-displaceable distribution volume (V ND ), and binding potential (BP ND ), can be determined from model parameters estimated by kinetic analysis. The stability of binding parameter estimates depends on the kinetic characteristics of radioligands. To describe these kinetic characteristics, we previously developed a two-phase graphic plot analysis in which V ND and V T can be estimated from the x-intercept of regression lines for early and delayed phases, respectively. In this study, we applied this graphic plot analysis to visual evaluation of the kinetic characteristics of radioligands for neuroreceptors, and investigated a relationship between the shape of these graphic plots and the stability of binding parameters estimated by the kinetic analysis with 2-TCM in simulated brain tissue time-activity curves (TACs) with various binding parameters. Methods 90-min TACs were generated with the arterial input function and assumed kinetic parameters according to 2-TCM. Graphic plot analysis was applied to these simulated TACs, and the curvature of the plot for each TAC was evaluated visually. TACs with several noise levels were also generated with various kinetic parameters, and the bias and variation of binding parameters estimated by kinetic analysis were calculated in each TAC. These bias and variation were compared with the shape of graphic plots. Results The graphic plots showed larger curvature for TACs with higher specific binding and slower dissociation of specific binding. The quartile deviations of V ND and BP ND determined by kinetic analysis were smaller for radioligands with slow dissociation. Conclusions The larger curvature of graphic plots for radioligands with slow dissociation might indicate a stable determination of V ND and BP ND by kinetic analysis. For
A sequential method to analyze the kinetics of biomass pyrolysis.
Huang, Y F; Kuan, W H; Chiueh, P T; Lo, S L
2011-10-01
The kinetics of biomass pyrolysis was studied via a sequential method including two stages. Stage one is to analyze the kinetics of biomass pyrolysis and starts with the determination of unreacted fraction of sample at the maximum reaction rate, (1-α)(m). Stage two provides a way to simulate the reaction rate profile and to verify the appropriateness of kinetic parameters calculated in the previous stage. Filter paper, xylan, and alkali lignin were used as representatives of cellulose, hemicellulose, and lignin whose pyrolysis was analyzed with the assumption of the orders of reaction being 1, 2, and 3, respectively. For most of the biomass pyrolysis, kinetic parameters were properly determined and reaction rate profiles were adequately simulated by regarding the order of reaction as 1. This new method should be applicable to most of the biomass pyrolysis and similar reactions whose (1-α)(m) is acquirable, representative, and reliable. Copyright © 2011 Elsevier Ltd. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Alca Ruiz, F.
1982-07-01
In this report one distribution of neutron counts obtained by a detector placed in a reactor is studied in order to be used in the determination of reactor kinetic parameters such as {beta}/{lambda} and reactivities. The parameters accuracy from this new method is compared with the Feynman and Mogilner method, based too in Reactor Neutron Noise Analysis. These three methods have been applied to JEN-2 reactor and the better accuracy and faster collection of experimental data give some interest to the new method which only requires a good footing code. (Author) 68 refs.
Batı, Mehmet; Ertaş, Mehmet
2017-05-01
The hysteresis properties of a kinetic mixed spin (1/2, 1) Ising ferrimagnetic system on a hexagonal lattice are studied by means of the dynamic mean field theory. In the present study, the effects of the nearest-neighbor interaction, temperature, frequency of oscillating magnetic field and the exchange anisotropy on the hysteresis properties of the kinetic system are discussed in detail. A number of interesting phenomena such as the shape of hysteresis loops with one, two, three and inverted-hysteresis/proteresis (butterfly shape hysteresis) have been obtained. Finally, the obtained results are compared with some experimental and theoretical results and a qualitatively good agreement is found.
Energy Technology Data Exchange (ETDEWEB)
Batı, Mehmet, E-mail: mehmet.bati@erdogan.edu.tr [Department of Physics, Recep Tayyip Erdoğan University, 53100 Rize (Turkey); Ertaş, Mehmet [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)
2017-05-15
The hysteresis properties of a kinetic mixed spin (1/2, 1) Ising ferrimagnetic system on a hexagonal lattice are studied by means of the dynamic mean field theory. In the present study, the effects of the nearest-neighbor interaction, temperature, frequency of oscillating magnetic field and the exchange anisotropy on the hysteresis properties of the kinetic system are discussed in detail. A number of interesting phenomena such as the shape of hysteresis loops with one, two, three and inverted-hysteresis/proteresis (butterfly shape hysteresis) have been obtained. Finally, the obtained results are compared with some experimental and theoretical results and a qualitatively good agreement is found.
Kinetics of transesterification of methyl acetate and n-octanol catalyzed by cation exchange resins
Energy Technology Data Exchange (ETDEWEB)
Liu, Yong; Gao, Li; Li, Xiying; Mao, Liqun [Henan University, Kaifeng (China); Wei, Min [Henan University of Technology, Zhengzhou (China)
2013-05-15
The transesterification kinetics of methyl acetate with n-octanol to octyl acetate and methanol were studied using Amberlyst 15 as catalyst in a batch stirred reactor. The influence of the agitation speed, particle size, temperature, catalyst loading, and initial reactants molar ratio was investigated in detail. A pseudo-homogeneous (PH) kinetic model was applied to correlate the experimental data in the temperature range of 313.15 K to 328.15 K. The estimated kinetic parameters made the calculated results in good agreement with the experimental data. A kinetic model describing the transesterification reaction catalyzed by cation exchange resins was developed.
Miyata, Tatsuhiko; Ikuta, Yasuhiro; Hirata, Fumio
2010-07-28
This article proposes a free energy calculation method based on the molecular dynamics simulation combined with the three dimensional reference interaction site model theory. This study employs the free energy perturbation (FEP) and the thermodynamic integration (TDI) along the coupling parameters to control the interaction potential. To illustrate the method, we applied it to a complex formation process in aqueous solutions between a crown ether molecule 18-Crown-6 (18C6) and a potassium ion as one of the simplest model systems. Two coupling parameters were introduced to switch the Lennard-Jones potential and the Coulomb potential separately. We tested two coupling procedures: one is a "sequential-coupling" to couple the Lennard-Jones interaction followed by the Coulomb coupling, and the other is a "mixed-coupling" to couple both the Lennard-Jones and the Coulomb interactions together as much as possible. The sequential-coupling both for FEP and TDI turned out to be accurate and easily handled since it was numerically well-behaved. Furthermore, it was found that the sequential-coupling had relatively small statistical errors. TDI along the mixed-coupling integral path was to be carried out carefully, paying attention to a numerical behavior of the integrand. The present model system exhibited a nonmonotonic behavior in the integrands for TDI along the mixed-coupling integral path and also showed a relatively large statistical error. A coincidence within a statistical error was obtained among the results of the free energy differences evaluated by FEP, TDI with the sequential-coupling, and TDI with the mixed-coupling. The last one is most attractive in terms of the computer power and is accurate enough if one uses a proper set of windows, taking the numerical behavior of the integrands into account. TDI along the sequential-coupling integral path would be the most convenient among the methods we tested, since it seemed to be well-balanced between the computational
Erbium hydride thermal desorption : controlling kinetics.
Energy Technology Data Exchange (ETDEWEB)
Ferrizz, Robert Matthew
2007-08-01
Thermal desorption spectroscopy (TDS) is used to study the decomposition kinetics of erbium hydride thin films. The TDS results presented in this report show that hydride film processing parameters directly impact thermal stability. Issues to be addressed include desorption kinetics for dihydrides and trihydrides, and the effect of film growth parameters, loading parameters, and substrate selection on desorption kinetics.
Energy Technology Data Exchange (ETDEWEB)
Alario, F.; Bamberger, A.; Benjelloun-Dabaghi, Z. [Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France)
1998-03-01
This article is an overview of the work carried out together by the DIMA and the Cinetique et Catalyse division of the Institut francais du petrole. It is a new mathematical approach to validate a kinetic formalization: the n-heptane dehydrocyclization which is an important reaction of the catalytic reforming. (authors) 5 refs.
Hellmann, Robert; Bich, Eckard; Vesovic, Velisa
2016-04-07
The thermal conductivity of low-density CH4-N2 gas mixtures has been calculated by means of the classical trajectory method using state-of-the-art intermolecular potential energy surfaces for the CH4-CH4, N2-N2, and CH4-N2 interactions. Results are reported in the temperature range from 70 K to 1200 K. Since the thermal conductivity is influenced by the vibrational degrees of freedom of the molecules, which are not included in the rigid-rotor classical trajectory computations, a new correction scheme to account for vibrational degrees of freedom in a dilute gas mixture is presented. The calculations show that the vibrational contribution at the highest temperature studied amounts to 46% of the total thermal conductivity of an equimolar mixture compared to 13% for pure nitrogen and 58% for pure methane. The agreement with the available experimental thermal conductivity data at room temperature is good, within ±1.4%, whereas at higher temperatures, larger deviations up to 4.5% are observed, which can be tentatively attributed to deteriorating performance of the measuring technique employed. Results are also reported for the magnitude and temperature dependence of the rotational collision number, Z(rot), for CH4 relaxing in collisions with N2 and for N2 relaxing in collisions with CH4. Both collision numbers increase with temperature, with the former being consistently about twice the value of the latter.
Energy Technology Data Exchange (ETDEWEB)
Reynolds, J. M.; Lopez-Bruna, D.
2009-12-11
This report is the first of a series dedicated to the numerical calculation of the evolution of fusion plasmas in general toroidal geometry, including TJ-II plasmas. A kinetic treatment has been chosen: the evolution equation of the distribution function of one or several plasma species is solved in guiding center coordinates. The distribution function is written as a Maxwellian one modulated by polynomial series in the kinetic coordinates with no other approximations than those of the guiding center itself and the computation capabilities. The code allows also for the inclusion of the three-dimensional electrostatic potential in a self-consistent manner, but the initial objective has been set to solving only the neoclassical transport. A high order conservative method (Spectral Difference Method) has been chosen in order to discretized the equation for its numerical solution. In this first report, in addition to justifying the work, the evolution equation and its approximations are described, as well as the baseline of the numerical procedures. (Author) 28 refs.
Bahamondes, Carola; Wilson, Lorena; Guzmán, Fanny; Illanes, Andrés
2017-12-01
The synthesis of the dipeptide N-benzoyl-l-tyrosine-l-argininamide (BTAA) was conducted under kinetic control with N-benzoyl-l-tyrosine ethyl ester as acyl donor and argininamide as nucleophile using immobilized α-chymotrypsin as catalyst. Using a mathematical procedure, the kinetic constants corresponding to the proposed mechanism of peptide synthesis were determined in three different cosolvent media, namely, ethanol, diglyme and acetonitrile. These constants were used for evaluating the selectivity of glyoxyl-agarose immobilized α-chymotrypsin in the synthesis of BTAA by determining the ratios of synthesis to hydrolysis rates. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.
Owhondah, R.; Walker, M.; Ma, L.; Nimmo, W.; Ingham, D.B.; Poggio, D.; Pourkashanian, M.
2016-01-01
Biochemical reactions occurring during anaerobic digestion have been modelled using reaction kinetic equations such as first-order, Contois and Monod which are then combined to form mechanistic models. This work considers models which include between one and three biochemical reactions to investigate if the choice of the reaction rate equation, complexity of the model structure as well as the inclusion of inhibition plays a key role in the ability of the model to describe the methane producti...
Energy Technology Data Exchange (ETDEWEB)
Li, L. H.; Hu, L.; Yang, S. J.; Wang, W. L.; Wei, B., E-mail: bbwei@nwpu.edu.cn [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China)
2016-01-21
The thermodynamic properties, including the density, volume expansion coefficient, ratio of specific heat to emissivity of intermetallic Ni{sub 7}Zr{sub 2} alloy, have been measured using the non-contact electrostatic levitation technique. These properties vary linearly with temperature at solid and liquid states, even down to the obtained maximum undercooling of 317 K. The enthalpy, glass transition, diffusion coefficient, shear viscosity, and surface tension were obtained by using molecular dynamics simulations. Ni{sub 7}Zr{sub 2} has a relatively poor glass forming ability, and the glass transition temperature is determined as 1026 K. The inter-diffusivity of Ni{sub 7}Zr{sub 2} alloy fitted by Vogel–Fulcher–Tammann law yields a fragility parameter of 8.49, which indicates the fragile nature of this alloy. Due to the competition of increased thermodynamic driving force and decreased atomic diffusion, the dendrite growth velocity of Ni{sub 7}Zr{sub 2} compound exhibits double-exponential relationship to the undercooling. The maximum growth velocity is predicted to be 0.45 m s{sup −1} at the undercooling of 335 K. Theoretical analysis reveals that the dendrite growth is a diffusion-controlled process and the atomic diffusion speed is only 2.0 m s{sup −1}.
Energy Technology Data Exchange (ETDEWEB)
Sengupta, Arijit, E-mail: arijita@barc.gov.in [Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Fang, Yuyu; Yuan, Xiangyang; Yuan, Lihua [Key Laboratory for Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, College of Chemistry, Sichuan University, Chengdu 610064 (China)
2015-10-15
An attempt was made to understand the complexation of Eu{sup 3+} with structurally modified CMPO-functionalized pillararenes by luminescence spectroscopy. Formation of single species with different numbers of inner sphere water molecules was found to be present for all the complexes. On increasing spacer length between ligating moieties and supramolecular pillararenes, the stereo-chemical crowding around ligating oxygen decreased. Therefore, strong covalent metal–oxygen bond was formed which was reflected in the increasing trend of the computed Ω{sub 2} values (Judd–Offelt parameter): LI (4.66×10{sup −20})
van den Berg, J.W.A.
1984-01-01
Application of UNIFAC computer calculations to polymer solutions does not seem to make sense because of the value of the solvent activity: close to 1.000 over a considerable range of concentrations (up to 90% of polymer). A simple procedure is proposed to calculate solvent activity coefficients, and
Directory of Open Access Journals (Sweden)
Nancy Acelas Soto
2010-01-01
Full Text Available The study of pyrolysis is gaining increasing importance, since it is the first step in the gasification or combustion process. In this study, pyrolysis experiments of cypress pine were carried out in a thermogravimetric analyzer at six different heating rates between 5 and 40 ºC / min. Kinetics parameters of pine were determined from TGA by using the differential and the maximum speed methods. Additionally, the distribution of activation energies was also carried out finding the values of 113.57 and 157.32 kJ/mol, which are in the range of activation energies reported for hemicellulose and cellulose, respectively, main components of wood.
Meana-Pañeda, Rubén; Truhlar, Donald G; Fernández-Ramos, Antonio
2011-03-07
We report a detailed theoretical study of the hydrogen abstraction reaction from methanol by atomic hydrogen. The study includes the analysis of thermal rate constants, branching ratios, and kinetic isotope effects. Specifically, we have performed high-level computations at the MC3BB level together with direct dynamics calculations by canonical variational transition state theory (CVT) with the microcanonically optimized multidimensional tunneling (μOMT) transmission coefficient (CVT/μOMT) to study both the CH(3)OH+H→CH(2)OH+H(2) (R1) reaction and the CH(3)OH+H→CH(3)O+H(2) (R2) reaction. The CVT/μOMT calculations show that reaction R1 dominates in the whole range 298≤T (K)≤2500 and that anharmonic effects on the torsional mode about the C-O bond are important, mainly at high temperatures. The activation energy for the total reaction sum of R1 and R2 reactions changes substantially with temperature and, therefore, the use of straight-line Arrhenius plots is not valid. We recommend the use of new expressions for the total R1 + R2 reaction and for the R1 and R2 individual reactions. © 2011 American Institute of Physics.
Berezhkovskiy, Leonid M
2009-02-01
The equation for the calculation of mean residence time of drug in plasma, t(p), is obtained. It is shown that the previously suggested calculation of t(p) considerably overestimates the true value in most cases. It is suggested that due to the possible initial (before establishing the uniform drug mixing in plasma) fast elimination of drug, the commonly calculated total body clearance (Cl = D/AUC) may substantially overestimate the clearance in the linear range of elimination of well-stirred drug. This would result in the high in vivo Cl values that are not supported by the in vitro studies of drug metabolism and stability in tissues. It is shown that the mean residence time of drug in the body, volumes of distribution, oral bioavailability and distribution clearance estimated with the account of initial drug distribution and elimination, may substantially deviate from the values obtained by the traditional calculations.
DEFF Research Database (Denmark)
van Leeuwen, Theo; Djonov, Emilia
2014-01-01
After discussing broad cultural drivers behind the development of kinetic typography, the chapter outlines an approach to analysing kinetic typography which is based on Halliday's theory of transitivity, as applied by Kress and Van Leeuwen to visual images....
Energy Technology Data Exchange (ETDEWEB)
Sogn, T.A.; Stuanes, A.O.; Abrahamsen, G.
1996-01-01
The conference paper deals with the accumulation of nitrogen in forests in Norway. The level of accumulation is a critical factor for the calculation of load limits. The paper compares the average rapidity values of accumulation since the last glacial age with the calculated values from the more short-lasting period based on data from surveying programs of the State Pollution Control Authority, manuring experiments, and other relevant research programs in this field. 8 refs., 1 fig., 1 tab.
Energy Technology Data Exchange (ETDEWEB)
Basurto G, B.S
2002-07-01
The objective of this work, is the one of determining the kinetic parameters of the dosemeter of LiF: Mg, Cu, P + Ptfe; starting from the curves Tl obtained at being irradiated with alpha radiation ({alpha}), beta ({beta}) and gamma ({gamma}). As like to compare its sensitivity with each radiation type, considering the sensitivity of the TLD-100 as the unit. In the Chapter 1, the fundamental structure of the matter is described, making emphasis in the different radiation types, and their interaction with this. In the Chapter 2, the units are described but used in the dosimetry of the radiation. In the Chapter 3, the basic concepts of the phenomenon of Tl are described and those are explained characteristic of the deconvolution method to determine the kinetics of the one phenomenon. In the Chapter 4, the methodology is detailed that was used in the elaboration of this thesis work, describing the material Tl that were considered like reference, as well as the sources of ionizing radiation, with those that the dosemeters were irradiated and the equipment in the one that the curves Tl was obtained. Reference is made to the software used to carry out the deconvolution of the curves Tl that were obtained in the one experimental development. In the Chapter 5, the obtained results of this study are presented, showing the tables of homogenization of dosemeters and the reading of the same one; they are observed the curves Tl obtained to different radiation doses (alpha, beta and gamma), the intensity Tl in function of the dose. Also they are tabulated, the obtained results in the kinetic parameters of the three different study materials (TLD-100H, USA; TLD-100, USA and LiF: Mg, Cu, P + Ptfe developed in the l.N.l.N). They are analyzed shortly for each material Tl their sensitivity to the ionizing radiation as well as their kinetic parameters. The obtained results showed that the Tl dosemeters of LiF: Mg,Cu,P + Ptfe, they presented a bigger sensitivity that the TLD-100 when
Kinetic parameters as determinants of vertical jump performance. DOI: 10.5007/1980-0037.2012v14n1p41
Saray Giovana dos Santos; Daniele Detanico; Juliano Dal pupo
2012-01-01
The aim of this study was to identify force and velocity parameters related to vertical jump performance in counter movement jump (CMJ) and squat jump (SJ), and to compare these parameters between sprint runners and volleyball players. Twenty-four male athletes (12 regional/national-level sprint runners and 12 national-level volleyball players) participated in this study. The athletes performed CMJ and SJ on a force platform. The following variables were analyzed: jump performance (jump heigh...
Kinetic parameters as determinants of vertical jump performance. DOI: 10.5007/1980-0037.2012v14n1p41
Juliano Dal pupo; Daniele Detanico; Saray Giovana dos Santos
2011-01-01
The aim of this study was to identify force and velocity parameters related to vertical jump performance in counter movement jump (CMJ) and squat jump (SJ), and to compare these parameters between sprint runners and volleyball players. Twenty-four male athletes (12 regional/national-level sprint runners and 12 national-level volleyball players) participated in this study. The athletes performed CMJ and SJ on a force platform. The following variables were analyzed: jump performance (jump heigh...
Kinzer-Ursem, Tamara L; Linderman, Jennifer J
2007-01-01
G protein–coupled receptors (GPCRs) exist in multiple dynamic states (e.g., ligand-bound, inactive, G protein–coupled) that influence G protein activation and ultimately response generation. In quantitative models of GPCR signaling that incorporate these varied states, parameter values are often uncharacterized or varied over large ranges, making identification of important parameters and signaling outcomes difficult to intuit. Here we identify the ligand- and cell-specific parameters that are important determinants of cell-response behavior in a dynamic model of GPCR signaling using parameter variation and sensitivity analysis. The character of response (i.e., positive/neutral/inverse agonism) is, not surprisingly, significantly influenced by a ligand's ability to bias the receptor into an active conformation. We also find that several cell-specific parameters, including the ratio of active to inactive receptor species, the rate constant for G protein activation, and expression levels of receptors and G proteins also dramatically influence agonism. Expressing either receptor or G protein in numbers several fold above or below endogenous levels may result in system behavior inconsistent with that measured in endogenous systems. Finally, small variations in cell-specific parameters identified by sensitivity analysis as significant determinants of response behavior are found to change ligand-induced responses from positive to negative, a phenomenon termed protean agonism. Our findings offer an explanation for protean agonism reported in β2--adrenergic and α2A-adrenergic receptor systems. PMID:17222056
Energy Technology Data Exchange (ETDEWEB)
Kumar, A. [Department of Physics, Ramjas College, University of Delhi, Delhi 110007 (India); Kumar, P. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Tripathy, M.R. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Arora, A.K. [Keshav Mahavidyalaya, University of Delhi, Keshavpuram, Delhi 110035 (India); Tandon, R.P. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)]. E-mail: rptandon9@physics.du.ac.in
2006-06-10
The effect of {gamma}-irradiation on oxygen content and kinetic parameters of high temperature ceramic Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO) superconductor have been investigated. The bulk samples prepared by the standard solid-state method were irradiated by {gamma}-rays of different dose in the range of 5.04 x 10{sup 3} to 4.23 x 10{sup 7} (R) at room temperature. The effects of irradiation on surface morphology viz. grain size, porosity and the presence of some impurity phases have been studied by scanning electron microscopy (SEM). The changes in transition temperature (T {sub c}) and the drop in T {sub c} ({delta}T) have been discussed in terms of change in oxygen value (O-value) in unirradiated and irradiated samples due to out-diffusion of oxygen. The oxygen contents {delta} for both the unirradiated and irradiated samples have been precisely determined by standard iodometric titration technique. The kinetic parameters viz. order of reaction (n) and activation energy (|{delta}E|) for both the samples have been precisely estimated by thermo gravimetric analysis (TGA). The effect of {gamma}-irradiation on irradiated samples has been studied by Infrared (IR)-spectroscopy.
Manjunath, S V; Kumar, S Mathava; Ngo, Huu Hao; Guo, Wenshan
2017-12-06
Metronidazole (MNZ) removal by two adsorbents, i.e., concrete-containing graphene (CG) and powder-activated carbon (PAC), was investigated via batch-mode experiments and the outcomes were used to analyze the kinetics, equilibrium and thermodynamics of MNZ adsorption. MNZ sorption on CG and PAC has followed the pseudo-second-order kinetic model, and the thermodynamic parameters revealed that MNZ adsorption was spontaneous on PAC and non-spontaneous on CG. Subsequently, two-parameter isotherm models, i.e., Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Elovich models, were applied to evaluate the MNZ adsorption capacity. The maximum MNZ adsorption capacities ([Formula: see text]) of PAC and CG were found to be between 25.5-32.8 mg/g and 0.41-0.002 mg/g, respectively. Subsequently, the effects of pH, temperature and adsorbent dosage on MNZ adsorption were evaluated by a central composite design (CCD) approach. The CCD experiments have pointed out the complete removal of MNZ at a much lower PAC dosage by increasing the system temperature (i.e., from 20°C to 40°C). On the other hand, a desorption experiment has shown 3.5% and 1.7% MNZ removal from the surface of PAC and CG, respectively, which was insignificant compared to the sorbed MNZ on the surface by adsorption. The overall findings indicate that PAC and CG with higher graphene content could be useful in MNZ removal from aqueous systems.
Energy Technology Data Exchange (ETDEWEB)
Nasir, Rubina; Mirza, Nasir M. [Dept. of, Physics, Air University, Islamabad (Pakistan); Mirza, Sikander M. [Dept. of, Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Sciences, Post Office Nilore, Islamabad (Pakistan)
2017-06-15
This work looks at the effect of changes in kinetic parameters on simultaneous reactivity insertions and beam tube flooding in a typical material testing reactor-type research reactor with low enriched high density (U{sub 3}Si{sub 2}-Al) fuel. Using a modified PARET code, various ramp reactivity insertions (from $0.1/0.5 s to $1.3/0.5 s) plus beam tube flooding ($0.5/0.25 s) accidents under uncontrolled conditions were analyzed to find their effects on peak power, net reactivity, and temperature. Then, the effects of changes in kinetic parameters including the Doppler coefficient, prompt neutron lifetime, and delayed neutron fractions on simultaneous reactivity insertion and beam tube flooding accidents were analyzed. Results show that the power peak values are significantly sensitive to the Doppler coefficient of the system in coupled accidents. The material testing reactor-type system under such a coupled accident is not very sensitive to changes in the prompt neutron life time; the core under such a coupled transient is not very sensitive to changes in the effective delayed neutron fraction.
Directory of Open Access Journals (Sweden)
Ivan Škiljaica
2015-06-01
Full Text Available Exploitation and technical parameters of a ship are very important qualitative characteristics which determine the efficiency of the use of any kind of transportation vessels both for pushboats and for pushed convoys as a whole. Some of the most important exploitation and technical parameters are: parameter of transport efficiency, tonnage quality parameter, and thrust output of propeller. The complexity of these parameters can be seen from the fact that they present the values of achieved payload-distance during transportation of cargo in the unit of time per unit of installed (or effective power of propelling engines of ships. The most reliable means for determining the transport efficiency is the method of testing in actual navigating conditions, which is conducted in order to determine exact technical characteristics of propelling engines of pushboats, and to determine drawbacks in their work and to increase their thrust and speed characteristics. This paper will present the process of choosing the size, shape, and number of barges in the convoy based on experiments conducted on a pushboat whose propelling engines have installed power 3×809.6 kW (3×1,100 HP. Obtained results are based on presumption that the total resistance of a pushed convoy is equal to the total thrust achieved by the ship’s propelling complex.
DEFF Research Database (Denmark)
Sauer, Stephan P. A.; Paidarová, Ivana; Oddershede, Jens
2011-01-01
The vibrational g factor, that is, the nonadiabatic correction to the vibrational reduced mass, of LiH has been calculated for internuclear distances over a wide range. Based on multiconfigurational wave functions with a large complete active space and an extended set of gaussian type basis...... functions, these calculations yielded also the rotational g factor, the electric dipolar moment, and its gradient with internuclear distance for LiH in its electronic ground state X (1)Sigma(+). The vibrational g factor g(v) exhibits a pronounced minimum near internuclear distance R = 3.65 x 10(-10) m...
Kinetic study of Mongolian coals by thermal analysis
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Jargalmaa S
2018-02-01
Full Text Available Thermal analysis was used for the thermal characterization of the coal samples. The experiments were performed to study the pyrolysis and gasification kinetics of typical Mongolian brown coals. Low rank coals from Shivee ovoo, Ulaan ovoo, Aduun chuluun and Baganuur deposits have been investigated. Coal samples were heated in the thermogravimetric apparatus under argon at a temperature ranges of 25-1020ºC with heating rates of 10, 20, 30 and 40ºC/min. Thermogravimetry (TG and derivative thermogravimetry (DTG were performed to measure weight changes and rates of weight losses used for calculating the kinetic parameters. The activation energy (Ea was calculated from the experimental results by using an Arrhenius type kinetic model.
Gangadhara; Ramesh Kumar, Parigi; Prakash, Vishweshwaraiah
2008-12-01
Invertase (beta-D -fructofuranoside fructohydrolase-E.C. 3.2.1.26) is a sucrose hydrolyzing enzyme found in microbial, plant and animal sources. Invertase from Candida utilis is a dimeric glycoprotein composed of two identical monomer subunits with an apparent molecular mass of 150 kDa. We investigated the mechanism of stabilization of invertase with polyols (glycerol, xylitol, and sorbitol). Activity, thermodynamic and kinetic measurements of invertase were performed as a function of polyol concentration and showed that polyols act as very effective stabilizing agents. The result from the solvent-invertase interaction shows preferential exclusion of the polyols from the protein domain leading to preferential hydration of protein. Apparent thermal denaturation temperature of the protein (T ( m )) rose from 75 degrees C to a maximum of 85 degrees C in 30% glycerol. The stabilization has been attributed to the preferential hydration of the enzyme.
Energy Technology Data Exchange (ETDEWEB)
Takeshita, E.V.; Krause, B.B.; Ulson de Souza, A.A.; Guelli U. Souza, S.M.A. [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Quimica e Engenharia de Alimentos]. E-mail: selene@enq.ufsc.br
2003-07-01
The objective of this work is to simulate a discharge and biodegradation of soluble products proceeding from one of the some ramifications of the Petroleum Industry in rivers. The one-dimensional model in transient regime is used to represent the mass transfer process in the river. A discharge with five species (isopropanol, acetone, methanol, phenol and LAS), gotten for petrochemical process, is simulated and the concentration profiles are obtained. The effect of the biodegradation on the concentration profile of these pollutants is verified. The kinetic models of Monod, Haldane and first-order are used to obtain the concentration profile in rivers. It is studied the influence of the temperature on biodegradation of these petrochemical products. (author)
Energy Technology Data Exchange (ETDEWEB)
Shuaibov, A. K.; Grabovaya, I. A.; Minya, A. I.; Homoki, Z. T. [Uzhgorod National University (Ukraine); Kalyuzhnaya, A. G.; Shchedrin, A. I. [National Academy of Sciences of Ukraine, Institute of Physics (Ukraine)
2011-03-15
A kinetic model of the processes occurring in the plasma of a high-power low-pressure gas-discharge lamp is presented, and the output characteristics of the lamp are described. The lamp is excited by a longitudinal glow discharge and emits the I{sub 2}(D Prime -A Prime ) 342-nm and XeI(B-X) 253-nm bands and the 206.2-nm spectral line of atomic iodine. When the emitter operates in a sealed-off mode on the p(He): p(Xe): p(I{sub 2}) = 400: 120: (100-200) Pa mixture, the fractions of the UV radiation power of iodine atoms, exciplex molecules of xenon iodide, and iodine molecules comprise 55, 10, and 35%, respectively. At the optimal partial pressure, the maximum total radiation power of the lamp reaches 37 W, the energy efficiency being about 15%.
Directory of Open Access Journals (Sweden)
Zul Adlan Mohd Hir
2017-10-01
Full Text Available A facile and effective technique to immobilize photocatalyst nanoparticles by incorporating zinc oxide (ZnO into polyethersulfone polymeric films by means of a phase inversion technique is reported. The degradation study of methyl orange (MO dye was performed using a series of ZnO-embedded polymer hybrid systems. The photoactivity of the films increased in parallel with increased ZnO loading up to 17 wt%. The photodegradation process followed a pseudo first-order kinetics with an achievement of almost 100% MO removal in original conditions. The PZ-17 film demonstrated an excellent and comparable degradation performance up to five cycles, signifying the reliability of the film photocatalyst against ultraviolet irradiation and degradation.
Directory of Open Access Journals (Sweden)
Seung-Kyo Oh
2013-01-01
Full Text Available The three-parameter Lennard-Jones (12-6 potential function is proposed to calculate thermodynamic property (second virial coefficient and transport properties (viscosity, thermal conductivity, and diffusion coefficient of noble gases (He, Ne, Ar, Kr, and Xe and their mixtures at low density. Empirical modification is made by introducing a reduced temperature-correction parameter τ to the Lennard-Jones potential function for this purpose. Potential parameters (σ, ε, and τ are determined individually for each species when the second virial coefficient and viscosity data are fitted together within the experimental uncertainties. Calculated thermodynamic and transport properties are compared with experimental data by using a single set of parameters. The present study yields parameter sets that have more physical significance than those of second virial coefficient methods and is more discriminative than the existing transport property methods in most cases of pure gases and of gas mixtures. In particular, the proposed model is proved with better results than those of the two-parameter Lennard-Jones (12-6 potential, Kihara Potential with group contribution concepts, and other existing methods.
Energy Technology Data Exchange (ETDEWEB)
Furmaniak, Sylwester; Terzyk, Artur P; Gauden, Piotr A [Department of Chemistry, Physicochemistry of Carbon Materials Research Group, N Copernicus University, Gagarin Street 7, 87-100 Torun (Poland); Kowalczyk, Piotr [Nanochemistry Research Institute, Curtin University, PO Box U1987, Perth, WA 6845 (Australia); Harris, Peter J F, E-mail: aterzyk@chem.uni.torun.pl [Centre for Advanced Microscopy, University of Reading, Whiteknights, Reading RG6 6AF (United Kingdom)
2011-10-05
Using grand canonical Monte Carlo simulation we show, for the first time, the influence of the carbon porosity and surface oxidation on the parameters of the Dubinin-Astakhov (DA) adsorption isotherm equation. We conclude that upon carbon surface oxidation, the adsorption decreases for all carbons studied. Moreover, the parameters of the DA model depend on the number of surface oxygen groups. That is why in the case of carbons containing surface polar groups, SF{sub 6} adsorption isotherm data cannot be used for characterization of the porosity. (paper)
Energy Technology Data Exchange (ETDEWEB)
Galindo G, I. F.; Vergara del C, J. A.; Galvan A, S. J. [Instituto Nacional de Electricidad y Energias Limpias, Reforma 113, Col. Palmira, 62490 Cuernavaca, Morelos (Mexico); Tijerina S, F., E-mail: francisco.tijerina@cfe.gob.mx [CFE, Central Nucleoelectrica Laguna Verde, Carretera Federal Cardel-Nautla Km 42.5, 91476 Municipio Alto Lucero, Veracruz (Mexico)
2016-09-15
The use of specialized codes to estimate the radiation dose projection to an emergency postulated event at a nuclear power plant requires that certain plant data be available according to the event being simulated. The calculation of the possible radiological release is the critical activity to carry out the emergency actions. However, not all of the plant data required are obtained directly from the plant but need to be calculated. In this paper we present a computational tool that calculates the plant data required to use the radiological dose estimation codes. The tool provides the required information when there is a gas emergency venting event in the primary containment atmosphere, whether well or dry well and also calculates the time in which the spent fuel pool would be discovered in the event of a leak of water on some of the walls or floor of the pool. The tool developed has mathematical models for the processes involved such as: compressible flow in pipes considering area change and for constant area, taking into account the effects of friction and for the case of the spent fuel pool hydraulic models to calculate the time in which a container is emptied. The models implemented in the tool are validated with data from the literature for simulated cases. The results with the tool are very similar to those of reference. This tool will also be very supportive so that in postulated emergency cases can use the radiological dose estimation codes to adequately and efficiently determine the actions to be taken in a way that affects as little as possible. (Author)
Zhang, Hongming; Wei, Jicheng; Yang, Qinke; Baartman, Jantiene E.M.; Gai, Lingtong; Yang, Xiaomei; Li, Shu Qin; Yu, Jiantao; Ritsema, Coen J.; Geissen, Violette
2017-01-01
The Universal Soil Loss Equation (USLE) and its revised version (RUSLE) are often used to estimate soil erosion at regional landscape scales. USLE/RUSLE contain parameters for slope length factor (L) and slope steepness factor (S), usually combined as LS. However a major limitation is the difficulty
Chemical, physical, and theoretical kinetics of an ultrafast folding protein.
Kubelka, Jan; Henry, Eric R; Cellmer, Troy; Hofrichter, James; Eaton, William A
2008-12-02
An extensive set of equilibrium and kinetic data is presented and analyzed for an ultrafast folding protein--the villin subdomain. The equilibrium data consist of the excess heat capacity, tryptophan fluorescence quantum yield, and natural circular-dichroism spectrum as a function of temperature, and the kinetic data consist of time courses of the quantum yield from nanosecond-laser temperature-jump experiments. The data are well fit with three kinds of models--a three-state chemical-kinetics model, a physical-kinetics model, and an Ising-like theoretical model that considers 10(5) possible conformations (microstates). In both the physical-kinetics and theoretical models, folding is described as diffusion on a one-dimensional free-energy surface. In the physical-kinetics model the reaction coordinate is unspecified, whereas in the theoretical model, order parameters, either the fraction of native contacts or the number of native residues, are used as reaction coordinates. The validity of these two reaction coordinates is demonstrated from calculation of the splitting probability from the rate matrix of the master equation for all 10(5) microstates. The analysis of the data on site-directed mutants using the chemical-kinetics model provides information on the structure of the transition-state ensemble; the physical-kinetics model allows an estimate of the height of the free-energy barrier separating the folded and unfolded states; and the theoretical model provides a detailed picture of the free-energy surface and a residue-by-residue description of the evolution of the folded structure, yet contains many fewer adjustable parameters than either the chemical- or physical-kinetics models.
Directory of Open Access Journals (Sweden)
Patsyuk V.
2015-12-01
Full Text Available The paper studies the problem of calculating the electric field of the 110kV electric lines of CSCPL (Controlled Self Compensating Power Lines type. The potential of electrical conductors is determined by a system of equations for voltages taking into account there phase shift at every moment of time. set of values of the voltages in the system, taking into account the phase shift of the voltage vectors in time. We dispose the possibilities that ensure to calculate the linear values of capacity and inductance of the line knowing the electric field characteristics for a given geometry. The electric line with the horizontal placement of wires is studied. The repartition of the electric field for the limited domain of a square with sides of 100x100 m, the edges of which have zero values of potential is determined. To obtain a numerical solution of Dirichlet formulated problem we will consider the domain as a set of small triangles. As the approximate solution of the formulated problem, we will consider the piecewise-defined function , which must be continuous in the domain and of linear nature on each triangle . To calculate the electric fields when changing the phase shifting angle for voltages of conductors displaced close to each other in the 0-1800 frequency band and of different values of discretization time on the period of fundamental wave of voltage, the method of finite volumes has been used. The results of numerical calculation of the character of repartition of the potential in the field of the line for different values of time and of a phase shift of the vectors of applied voltages to the conductors of close phases for the 110 kV line of CSCPL type have been showed.
Pal, Partha P.; Manam, J.
2013-07-01
This paper reports the detail description of the structural and thermoluminescence of the RE3+-doped (RE=Eu, Tb) ZnO nanorods prepared by adopting co-precipitation method. Formation of as synthesized ZnO nanorods were confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD pattern showed monophasic nature of the as prepared ZnO doped with Eu3+ and Tb3+ ions. The SEM image elaborates the nanorod morphology of RE3+ doped ZnO with diameter ranging between 60-90 nm and length between 600-900 nm. The thermoluminescence spectra of the X-ray irradiated ZnO:Eu3+ and ZnO:Tb3+ show the prominent peak for the broad glow curve peaked at 365 °C and 350 °C, respectively, which have been generated via the recombination of the released electrons from the traps upon thermal stimulation. The peaks are found to obey first order kinetics and the activation energy for the ZnO:Eu3+ and ZnO:Tb3+ samples, estimated via isothermal luminescence glow peak decay method, are found to be 0.8 eV and 0.9 eV respectively. Furthermore, the TL dose response and reproducibility were also studied in details, which could be very useful to establish the potentiality of the present phosphors in the field of radiation dosimetry.
Directory of Open Access Journals (Sweden)
Borikar, D. K.
2006-01-01
Full Text Available The electrodeposition of nickel from nickel sulphate bath was studied in ammonia medium. The electrolytic conditions for nickel deposition was optimized at room temperature. The effect of acetone on current efficiency, morphology, stability and particle size of deposited nickel powder was studied. The effect of organic additive Tribenzyl ammonium chloride (TBAC on the morphology of nickel powder was also studied. The kinetics of electrodeposition was studied and the results were utilized in developing mathematical model. During electrodeposition the current efficiency was found to increase with increase in acetone concentration up to 15% V/V in bath solution. On further increase of acetone concentration in bath solution current efficiency decreases. The stability of the electrowon deposited nickel powder was found to be in the range of 85 to 89 %. Powder morphology was found to be dentritic, porous and irregular. The morphology was also found to be underdeveloped dentritic to rounded aggregate as the concentration of organic additive TBAC increases. The average particle size of the deposited powder was found to be decreasing as the concentration of the acetone increases. The average size of the particle is in the range of 13-16 m.
Báez, María E; Fuentes, Edwar; Espinoza, Jeannette
2013-07-03
Atrazine sorption was studied in six Andisol and Ultisol soils. Humic and fulvic acids and humin contributions were established. Sorption on soils was well described by the Freundlich model. Kf values ranged from 2.2-15.6 μg(1-1/n)mL(1/n)g⁻¹. The relevance of humic acid and humin was deduced from isotherm and kinetics experiments. KOC values varied between 221 and 679 mLg⁻¹ for these fractions. Fulvic acid presented low binding capacity. Sorption was controlled by instantaneous equilibrium followed by a time-dependent phase. The Elovich equation, intraparticle diffusion model, and a two-site nonequilibrium model allowed us to conclude that (i) there are two rate-limited phases in Andisols related to intrasorbent diffusion in organic matter and retarded intraparticle diffusion in the organo-mineral complex and that (ii) there is one rate-limited phase in Ultisols attributed to the mineral composition. The lower organic matter content of Ultisols and the slower sorption rate and mechanisms involved must be considered to assess the leaching behavior of atrazine.
Energy Technology Data Exchange (ETDEWEB)
Crus, Maria Ursulina de L. [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), Sao Paulo, SP (Brazil)]. E-mail: lirusbr@yahoo.com.br; Nascimento, Claudio A.O. [Sao Paulo Univ., SP (Brazil). Escola Politecnica. Dept. de Engenharia Quimica]. E-mail: oller@usp.br; Migliavacca, Sylvana C.P. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: scavedon@net.ipen.br
2005-07-01
The neural network model for the prediction and optimization of the separation parameters of a gas centrifuge for uranium enrichment has been proved to be an efficient tool. But it requires a reliable data base and an extensive knowledge of the experimenter to define the input and output variables. In the present work, the authors use a hybrid neural network phenomenological approach to model the separative parameters of a gas centrifuge. The neural network part of the model is constituted of a feed forward neural network, trained with the back-propagation algorithm that receives the input data and calculates the internal parameters that can not be measured experimentally, for the phenomenological part of the model. This last one, receives the input data plus the internal parameters