Science.gov

Sample records for kinetics parameters variations

  1. Non-Isothermic Chemical Kinetics in the Undergraduate Laboratory: Arrhenius Parameters from Experiments with Hyperbolic Temperature Variation.

    ERIC Educational Resources Information Center

    Salvador, F.; And Others

    1984-01-01

    Describes a method which adapts itself to the characteristics of the kinetics of a chemical reaction in solution, enabling students to determine the Arrhenius parameters with satisfactory accuracy by means of a single non-isothermic experiment. Both activation energy and the preexponential factor values can be obtained by the method. (JN)

  2. Kinetic parameters from thermogravimetric analysis

    NASA Technical Reports Server (NTRS)

    Kiefer, Richard L.

    1993-01-01

    High performance polymeric materials are finding increased use in aerospace applications. Proposed high speed aircraft will require materials to withstand high temperatures in an oxidative atmosphere for long periods of time. It is essential that accurate estimates be made of the performance of these materials at the given conditions of temperature and time. Temperatures of 350 F (177 C) and times of 60,000 to 100,000 hours are anticipated. In order to survey a large number of high performance polymeric materials on a reasonable time scale, some form of accelerated testing must be performed. A knowledge of the rate of a process can be used to predict the lifetime of that process. Thermogravimetric analysis (TGA) has frequently been used to determine kinetic information for degradation reactions in polymeric materials. Flynn and Wall studied a number of methods for using TGA experiments to determine kinetic information in polymer reactions. Kinetic parameters, such as the apparent activation energy and the frequency factor, can be determined in such experiments. Recently, researchers at the McDonnell Douglas Research Laboratory suggested that a graph of the logarithm of the frequency factor against the apparent activation energy can be used to predict long-term thermo-oxidative stability for polymeric materials. Such a graph has been called a kinetic map. In this study, thermogravimetric analyses were performed in air to study the thermo-oxidative degradation of several high performance polymers and to plot their kinetic parameters on a kinetic map.

  3. Photochemical ozone creation potentials for oxygenated volatile organic compounds: sensitivity to variations in kinetic and mechanistic parameters

    NASA Astrophysics Data System (ADS)

    Jenkin, Michael E.; Hayman, Garry D.

    The sensitivity of Photochemical Ozone Creation Potentials (POCP) to a series of systematic variations in the rates and products of reactions of radical intermediates and oxygenated products is investigated for the C 4 alcohols, 1-butanol ( n-butanol) and 2-methyl-1-propanol ( i-butanol), using the recently developed Master Chemical Mechanism (MCM) as the base case. The POCP values are determined from the calculated formation of ozone in the boundary layer over a period of approximately five days along an idealised straight line trajectory, using a photochemical trajectory model and methodology described in detail previously. The results allow the relative impacts on calculated ozone formation of various classes of chemical reaction within the degradation chemistry to be assessed. The calculated POCP is found to be very insensitive to many of the changes investigated. However, it is found to be sensitive to variations in the rate coefficient for the initiating reaction with OH ( kOH), although the sensitivity decreases with increasing kOH. The POCP appears to vary approximately linearly with kOH at low values (i.e. kOH less than ca. 4×10 -13 cm 3 molecule -1 s -1), whereas at high reactivities (i.e. kOH greater than ca. 4×10 -11 cm 3 molecule -1 s -1), the calculated POCP value is comparatively insensitive to the precise value of kOH. The POCP is also very sensitive to mechanistic changes which influence the yields of unreactive oxygenated products (i.e. those with OH reactivities below ca. 10 -12 cm 3 molecule -1 s -1), for example acetone. The propensity of the organic compound to produce organic nitrates (which act as comparatively unreactive reservoirs for free radicals and NO x) also appears to have a notable influence on the calculated POCP. Recently reported information relevant to the degradation of oxygenated VOCs is then used to update the chemical schemes for the 17 alcohols and glycols, 10 ethers and glycol ethers, and 8 esters included in the MCM

  4. Magnetic hyperthermia properties of nanoparticles inside lysosomes using kinetic Monte Carlo simulations: Influence of key parameters and dipolar interactions, and evidence for strong spatial variation of heating power

    NASA Astrophysics Data System (ADS)

    Tan, R. P.; Carrey, J.; Respaud, M.

    2014-12-01

    Understanding the influence of dipolar interactions in magnetic hyperthermia experiments is of crucial importance for fine optimization of nanoparticle (NP) heating power. In this study we use a kinetic Monte Carlo algorithm to calculate hysteresis loops that correctly account for both time and temperature. This algorithm is shown to correctly reproduce the high-frequency hysteresis loop of both superparamagnetic and ferromagnetic NPs without any ad hoc or artificial parameters. The algorithm is easily parallelizable with a good speed-up behavior, which considerably decreases the calculation time on several processors and enables the study of assemblies of several thousands of NPs. The specific absorption rate (SAR) of magnetic NPs dispersed inside spherical lysosomes is studied as a function of several key parameters: volume concentration, applied magnetic field, lysosome size, NP diameter, and anisotropy. The influence of these parameters is illustrated and comprehensively explained. In summary, magnetic interactions increase the coercive field, saturation field, and hysteresis area of major loops. However, for small amplitude magnetic fields such as those used in magnetic hyperthermia, the heating power as a function of concentration can increase, decrease, or display a bell shape, depending on the relationship between the applied magnetic field and the coercive/saturation fields of the NPs. The hysteresis area is found to be well correlated with the parallel or antiparallel nature of the dipolar field acting on each particle. The heating power of a given NP is strongly influenced by a local concentration involving approximately 20 neighbors. Because this local concentration strongly decreases upon approaching the surface, the heating power increases or decreases in the vicinity of the lysosome membrane. The amplitude of variation reaches more than one order of magnitude in certain conditions. This transition occurs on a thickness corresponding to approximately

  5. qPIPSA: Relating enzymatic kinetic parameters and interaction fields

    PubMed Central

    Gabdoulline, Razif R; Stein, Matthias; Wade, Rebecca C

    2007-01-01

    . Outliers may arise due to variation in the importance of different contributions to the kinetic parameters, such as protein stability and conformational changes. The qPIPSA approach can assist in the validation as well as estimation of kinetic parameters, and provide insights into enzyme mechanism. PMID:17919319

  6. Determination of kinetic parameters for biomass combustion.

    PubMed

    Álvarez, A; Pizarro, C; García, R; Bueno, J L; Lavín, A G

    2016-09-01

    The aim of this work is to provide a wide database of kinetic data for the most common biomass by thermogravimetric analysis (TGA) and differential thermogravimetry (DTG). Due to the characteristic parameters of DTG curves, a two-stage reaction model is proposed and the kinetic parameters obtained from model-based methods with energy activation values for first and second stages in the range 1.75·10(4)-1.55·10(5)J/mol and 1.62·10(4)-2.37·10(5)J/mol, respectively. However, it has been found that Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose model-free methods are not suitable to determine the kinetic parameters of biomass combustion since the assumptions of these two methods were not accomplished in the full range of the combustion process. PMID:27233095

  7. Variation of Parameters in Differential Equations (A Variation in Making Sense of Variation of Parameters)

    ERIC Educational Resources Information Center

    Quinn, Terry; Rai, Sanjay

    2012-01-01

    The method of variation of parameters can be found in most undergraduate textbooks on differential equations. The method leads to solutions of the non-homogeneous equation of the form y = u[subscript 1]y[subscript 1] + u[subscript 2]y[subscript 2], a sum of function products using solutions to the homogeneous equation y[subscript 1] and…

  8. The use of automated parameter searches to improve ion channel kinetics for neural modeling.

    PubMed

    Hendrickson, Eric B; Edgerton, Jeremy R; Jaeger, Dieter

    2011-10-01

    The voltage and time dependence of ion channels can be regulated, notably by phosphorylation, interaction with phospholipids, and binding to auxiliary subunits. Many parameter variation studies have set conductance densities free while leaving kinetic channel properties fixed as the experimental constraints on the latter are usually better than on the former. Because individual cells can tightly regulate their ion channel properties, we suggest that kinetic parameters may be profitably set free during model optimization in order to both improve matches to data and refine kinetic parameters. To this end, we analyzed the parameter optimization of reduced models of three electrophysiologically characterized and morphologically reconstructed globus pallidus neurons. We performed two automated searches with different types of free parameters. First, conductance density parameters were set free. Even the best resulting models exhibited unavoidable problems which were due to limitations in our channel kinetics. We next set channel kinetics free for the optimized density matches and obtained significantly improved model performance. Some kinetic parameters consistently shifted to similar new values in multiple runs across three models, suggesting the possibility for tailored improvements to channel models. These results suggest that optimized channel kinetics can improve model matches to experimental voltage traces, particularly for channels characterized under different experimental conditions than recorded data to be matched by a model. The resulting shifts in channel kinetics from the original template provide valuable guidance for future experimental efforts to determine the detailed kinetics of channel isoforms and possible modulated states in particular types of neurons. PMID:21243419

  9. Seasonal variations of haematological parameters in athletes.

    PubMed

    Banfi, Giuseppe; Lundby, Carsten; Robach, Paul; Lippi, Giuseppe

    2011-01-01

    The influence of training and competition workloads is crucial for evaluation of longitudinal haematological data in athletes. There are only a few papers on the variation of haematological parameters during long-lasting periods and, especially, during an entire competitive season. We summarized that some haematological parameters can be influenced by long-term training and competition periods. Haemoglobin (Hb) and haematocrit (Ht) are decreased during the more intense periods of training, throughout the season. In different sport disciplines, the decline of Hb ranges from 3 to 8% during the competition season, while the range of reticulocytes (Ret%) varies from 5 to 21%. Reticulocytes are also decreased after long periods of training and competitions, but their variation is not necessarily associated with that of Hb. The qualitative variations (trend of modifications) of haematological parameters are roughly independent of the sport discipline, but quantitatively (amount of modifications) dependent on sport discipline. The modifications are more evident in cycling, running, swimming than they are in football and rugby. The variations of haematological parameters within the same sport discipline are qualitatively concordant and quantitatively different among separate but consecutive competitive seasons. These findings are described in aerobic and team sports sportsmen. The definition of reliable reference ranges in sportsmen would only be possible by following the best laboratory practices. For antidoping purposes more studies investigating haematological modifications during the season are advisable. PMID:20842374

  10. Obtaining and estimating kinetic parameters from the literature.

    PubMed

    Neves, Susana R

    2011-09-20

    This Teaching Resource provides lecture notes, slides, and a student assignment for a lecture on strategies for the development of mathematical models. Many biological processes can be represented mathematically as systems of ordinary differential equations (ODEs). Simulations with these mathematical models can provide mechanistic insight into the underlying biology of the system. A prerequisite for running simulations, however, is the identification of kinetic parameters that correspond closely with the biological reality. This lecture presents an overview of the steps required for the development of kinetic ODE models and describes experimental methods that can yield kinetic parameters and concentrations of reactants, which are essential for the development of kinetic models. Strategies are provided to extract necessary parameters from published data. The homework assignment requires students to find parameters appropriate for a well-studied biological regulatory system, convert these parameters into appropriate units, and interpret how different values of these parameters may lead to different biological behaviors. PMID:21934111

  11. Obtaining and Estimating Kinetic Parameters from the Literature

    PubMed Central

    Neves, Susana R.

    2014-01-01

    This Teaching Resource provides lecture notes, slides, and a student assignment for a lecture on strategies for the development of mathematical models. Many biological processes can be represented mathematically as systems of ordinary differential equations (ODEs). Simulations with these mathematical models can provide mechanistic insight into the underlying biology of the system. A prerequisite for running simulations, however, is the identification of kinetic parameters that correspond closely with the biological reality. This lecture presents an overview of the steps required for the development of kinetic ODE models and describes experimental methods that can yield kinetic parameters and concentrations of reactants, which are essential for the development of kinetic models. Strategies are provided to extract necessary parameters from published data. The homework assignment requires students to find parameters appropriate for a well-studied biological regulatory system, convert these parameters into appropriate units, and interpret how different values of these parameters may lead to different biological behaviors. PMID:21934111

  12. UPRE method for total variation parameter selection

    SciTech Connect

    Wohlberg, Brendt; Lin, Youzuo

    2008-01-01

    Total Variation (TV) Regularization is an important method for solving a wide variety of inverse problems in image processing. In order to optimize the reconstructed image, it is important to choose the optimal regularization parameter. The Unbiased Predictive Risk Estimator (UPRE) has been shown to give a very good estimate of this parameter for Tikhonov Regularization. In this paper we propose an approach to extend UPRE method to the TV problem. However, applying the extended UPRE is impractical in the case of inverse problems such as de blurring, due to the large scale of the associated linear problem. We also propose an approach to reducing the large scale problem to a small problem, significantly reducing computational requirements while providing a good approximation to the original problem.

  13. Macroscopic Kinetic Effect of Cell-to-Cell Variation in Biochemical Reactions

    NASA Astrophysics Data System (ADS)

    Kim, Pan-Jun; Price, Nathan D.

    2010-04-01

    Genetically identical cells under the same environmental conditions can show strong variations in protein copy numbers due to inherently stochastic events in individual cells. We here develop a theoretical framework to address how variations in enzyme abundance affect the collective kinetics of metabolic reactions observed within a population of cells. Kinetic parameters measured at the cell population level are shown to be systematically deviated from those of single cells, even within populations of homogeneous parameters. Because of these considerations, Michaelis-Menten kinetics can even be inappropriate to apply at the population level. Our findings elucidate a novel origin of discrepancy between in vivo and in vitro kinetics, and offer potential utility for analysis of single-cell metabolomic data.

  14. Kinetic parameters of some tissue equivalent thermoluminescence materials

    NASA Astrophysics Data System (ADS)

    Kitis, G.; Furetta, C.; Prokic, M.; Prokic, V.

    2000-06-01

    The paper reports a study on the kinetic parameters of some thermoluminescent tissue equivalent materials recently prepared in Vinca Institute: Li2B4O7:Mn,Si, Li2B4O7:Cu, Li2B4O7:Cu,In and MgB4O7:Dy,Na. The kinetics parameters have been determined using several methods. The temperature lag effect, which could produce large errors in the parameters' determination when they are determined using high heating rates, has also been taken into consideration.

  15. Estimation of beech pyrolysis kinetic parameters by Shuffled Complex Evolution.

    PubMed

    Ding, Yanming; Wang, Changjian; Chaos, Marcos; Chen, Ruiyu; Lu, Shouxiang

    2016-01-01

    The pyrolysis kinetics of a typical biomass energy feedstock, beech, was investigated based on thermogravimetric analysis over a wide heating rate range from 5K/min to 80K/min. A three-component (corresponding to hemicellulose, cellulose and lignin) parallel decomposition reaction scheme was applied to describe the experimental data. The resulting kinetic reaction model was coupled to an evolutionary optimization algorithm (Shuffled Complex Evolution, SCE) to obtain model parameters. To the authors' knowledge, this is the first study in which SCE has been used in the context of thermogravimetry. The kinetic parameters were simultaneously optimized against data for 10, 20 and 60K/min heating rates, providing excellent fits to experimental data. Furthermore, it was shown that the optimized parameters were applicable to heating rates (5 and 80K/min) beyond those used to generate them. Finally, the predicted results based on optimized parameters were contrasted with those based on the literature. PMID:26551654

  16. Breakdown parameter for kinetic modeling of multiscale gas flows.

    PubMed

    Meng, Jianping; Dongari, Nishanth; Reese, Jason M; Zhang, Yonghao

    2014-06-01

    Multiscale methods built purely on the kinetic theory of gases provide information about the molecular velocity distribution function. It is therefore both important and feasible to establish new breakdown parameters for assessing the appropriateness of a fluid description at the continuum level by utilizing kinetic information rather than macroscopic flow quantities alone. We propose a new kinetic criterion to indirectly assess the errors introduced by a continuum-level description of the gas flow. The analysis, which includes numerical demonstrations, focuses on the validity of the Navier-Stokes-Fourier equations and corresponding kinetic models and reveals that the new criterion can consistently indicate the validity of continuum-level modeling in both low-speed and high-speed flows at different Knudsen numbers. PMID:25019910

  17. Determining crystal growth kinetic parameters using optical fibre sensors

    NASA Astrophysics Data System (ADS)

    Boerkamp, M.; Lamb, D. W.; Lye, P. G.

    2012-12-01

    The capability of an 'intrinsic exposed core optical fibre sensor' (IECOFS) as a monitoring device of scale formation has been evaluated. The IECOFS has been used to measure kinetics parameters of calcium carbonate heterogeneous crystal growth such as the activation energy, the crystal growth rate and the induction time. The IECOFS was able to evaluate crystal growth inhibition through the use of chemical inhibitors.

  18. Least-squares estimation of batch culture kinetic parameters.

    PubMed

    Ong, S L

    1983-10-01

    This article concerns the development of a simple and effective least-squares procedure for estimating the kinetic parameters in Monod expressions from batch culture data. The basic approach employed in this work was to translate the problem of parameter estimation to a mathematical model containing a single decision variable. The resulting model was then solved by an efficient one-dimensional search algorithm which can be adapted to any microcomputer or advanced programmable calculator. The procedure was tested on synthetic data (substrate concentrations) with different types and levels of error. The effect of endogeneous respiration on the estimated values of the kinetic parameters was also assessed. From the results of these analyses the least-squares procedure developed was concluded to be very effective. PMID:18548565

  19. Spectroscopic determination of kinetic parameters for frequency sweeping Alfven eigenmodes

    SciTech Connect

    Lesur, M.; Idomura, Y.; Shinohara, K.; Garbet, X.

    2010-12-15

    A method for analyzing fundamental kinetic plasma parameters, such as linear drive and external damping rate, based on experimental observations of chirping Alfven eigenmodes, is presented. The method, which relies on new semiempirical laws for nonlinear chirping characteristics, consists of fitting procedures between the so-called Berk-Breizman model and the experiment in a quasiperiodic chirping regime. This approach is applied to the toroidicity induced Alfven eigenmode (TAE) on JT-60 Upgrade (JT-60U) [N. Oyama et al., Nucl. Fusion 49, 104007 (2009)], which yields an estimation of the kinetic parameters and suggests the existence of TAEs far from marginal stability. Two collision models are considered, and it is shown that dynamical friction and velocity-space diffusion are essential to reproduce nonlinear features observed in experiments. The results are validated by recovering measured growth and decay of perturbation amplitude and by estimating collision frequencies from experimental equilibrium data.

  20. Variational energy principle for compressible, baroclinic flow. 1: First and second variations of total kinetic action

    NASA Technical Reports Server (NTRS)

    Schmid, L. A.

    1977-01-01

    The case of a cold gas in the absence of external force fields is considered. Since the only energy involved is kinetic energy, the total kinetic action (i.e., the space-time integral of the kinetic energy density) should serve as the total free-energy functional in this case, and as such should be a local minimum for all possible fluctuations about stable flow. This conjecture is tested by calculating explicit, manifestly covariant expressions for the first and second variations of the total kinetic action in the context of Lagrangian kinematics. The general question of the correlation between physical stability and the convexity of any action integral that can be interpreted as the total free-energy functional of the flow is discussed and illustrated for the cases of rectillinear and rotating shearing flows.

  1. Evaluation of kinetic parameters for water soluble crystals by thermo gravimetric analysis

    NASA Astrophysics Data System (ADS)

    Rama, S.; Surendra Dilip, C.; Perumal, Rajesh Narayana

    2015-01-01

    This work elevates the relevance of kinetic parameters of nucleation and thermal decomposition for water soluble crystals. The positive soluble Potassium Dihydrogen Phosphate (KDP) and negative soluble Lithium Sulfate Monohydrate (LSMH) materials were chosen for the kinetic evaluation. The results obtained from the classical nucleation theory are verified with the kinetic parameters which are evaluated from thermo gravimetric analysis. Nucleation parameters of a crystallization process such as interfacial energy (σ), volume free energy (ΔGv), critical energy barrier for nucleation (ΔG*), radius of the critical nucleus (r*) and nucleation rate (J) of the positive (KDP) and negative solubility (LSMH) crystals are determined from the classical nucleation theory of solubility-enthalpy relation. The kinetic parameters viz. the order of reaction, enthalpy, Gibbs free energy of activation, frequency factor, and entropy of activation are obtained from the TG based models viz. Horowitz-Metzger, Coats-Redfern and Piloyan-Novikova. The effect of varying temperature with relative variation on Gibbs free energy for both positive and negative solubility crystals is also discussed. The developed model holds good for both positive and negative solubility crystals.

  2. Vibroacoustic test plan evaluation: Parameter variation study

    NASA Technical Reports Server (NTRS)

    Stahle, C. V.; Gongloef, H. R.

    1976-01-01

    Statistical decision models are shown to provide a viable method of evaluating the cost effectiveness of alternate vibroacoustic test plans and the associated test levels. The methodology developed provides a major step toward the development of a realistic tool to quantitatively tailor test programs to specific payloads. Testing is considered at the no test, component, subassembly, or system level of assembly. Component redundancy and partial loss of flight data are considered. Most and probabilistic costs are considered, and incipient failures resulting from ground tests are treated. Optimums defining both component and assembly test levels are indicated for the modified test plans considered. modeling simplifications must be considered in interpreting the results relative to a particular payload. New parameters introduced were a no test option, flight by flight failure probabilities, and a cost to design components for higher vibration requirements. Parameters varied were the shuttle payload bay internal acoustic environment, the STS launch cost, the component retest/repair cost, and the amount of redundancy in the housekeeping section of the payload reliability model.

  3. Kinetic parameters of composite propellants from thermogravimetric data

    SciTech Connect

    Rao, V.K.; Bardon, M.F.; Stowe, R.A.

    1995-07-01

    This paper presents a method of estimating all three global kinetic parameters, A (preexponential factor), E (energy of activation), and n (reaction order), from the results of a single dynamic (nonisothermal) thermogravimetry (TG) run on a propellant sample. The procedure will also show how satisfactorily pyrolysis of the propellant can be represented by the simple relation of Eq. 4 (d{alpha}/dT = (1{minus}{alpha}){sup n}(A/{phi})e{sup {minus}E/RT}) with constant values of A, E, and n where {alpha} = fractional reaction, T = temperature, {phi} = programmed increase in T, and R = universal gas constant.

  4. [Photosynthetic Parameters Inversion Algorithm Study Based on Chlorophyll Fluorescence Induction Kinetics Curve].

    PubMed

    Qiu, Xiao-han; Zhang, Yu-jun; Yin, Gao-fang; Shi, Chao-yi; Yu, Xiao-ya; Zhao, Nan-jing; Liu, Wen-qing

    2015-08-01

    The fast chlorophyll fluorescence induction curve contains rich information of photosynthesis. It can reflect various information of vegetation, such as, the survival status, the pathological condition and the physiology trends under the stress state. Through the acquisition of algae fluorescence and induced optical signal, the fast phase of chlorophyll fluorescence kinetics curve was fitted. Based on least square fitting method, we introduced adaptive minimum error approaching method for fast multivariate nonlinear regression fitting toward chlorophyll fluorescence kinetics curve. We realized Fo (fixedfluorescent), Fm (maximum fluorescence yield), σPSII (PSII functional absorption cross section) details parameters inversion and the photosynthetic parameters inversion of Chlorella pyrenoidosa. And we also studied physiological variation of Chlorella pyrenoidosa under the stress of Cu(2+). PMID:26672292

  5. On a variational approach to some parameter estimation problems

    NASA Technical Reports Server (NTRS)

    Banks, H. T.

    1985-01-01

    Examples (1-D seismic, large flexible structures, bioturbation, nonlinear population dispersal) in which a variation setting can provide a convenient framework for convergence and stability arguments in parameter estimation problems are considered. Some of these examples are 1-D seismic, large flexible structures, bioturbation, and nonlinear population dispersal. Arguments for convergence and stability via a variational approach of least squares formulations of parameter estimation problems for partial differential equations is one aspect of the problem considered.

  6. Cell population kinetic parameters for acute epidermal reactions in man

    SciTech Connect

    Cohen, L.

    1986-11-01

    Cell population kinetic parameters for acute reactions in squamous epithelium were estimated using available data on skin tolerance doses. Roughly equivalent doses for kilovoltage radiation delivered in equal daily fractions, as reported by F. Ellis (Br. J. Radiol. 15, 348-350 (1942)) and by R. Paterson (The Treatment of Malignant Disease by Radium and X-Rays. Edward Arnold, London, 1948), were combined with data for nonstandard fractionation at longer intervals of 1 or 2 weeks. By analyzing the combined data set, well-determined parameters could be derived. The data show that repopulation, with a potential cell doubling time of about 7 days, must occur in irradiated human skin, though this may possibly be limited to no more than seven doublings. The parameters derived are distinctly different from those associated with late-reacting dose-limiting tissues. The main difference is the steeper initial slope of the computed survival curve, that is a larger J parameter (multitarget model) or a larger alpha component (linear-quadratic model).

  7. Parameter estimation for models of ligninolytic and cellulolytic enzyme kinetics

    SciTech Connect

    Wang, Gangsheng; Post, Wilfred M; Mayes, Melanie; Frerichs, Joshua T; Jagadamma, Sindhu

    2012-01-01

    While soil enzymes have been explicitly included in the soil organic carbon (SOC) decomposition models, there is a serious lack of suitable data for model parameterization. This study provides well-documented enzymatic parameters for application in enzyme-driven SOC decomposition models from a compilation and analysis of published measurements. In particular, we developed appropriate kinetic parameters for five typical ligninolytic and cellulolytic enzymes ( -glucosidase, cellobiohydrolase, endo-glucanase, peroxidase, and phenol oxidase). The kinetic parameters included the maximum specific enzyme activity (Vmax) and half-saturation constant (Km) in the Michaelis-Menten equation. The activation energy (Ea) and the pH optimum and sensitivity (pHopt and pHsen) were also analyzed. pHsen was estimated by fitting an exponential-quadratic function. The Vmax values, often presented in different units under various measurement conditions, were converted into the same units at a reference temperature (20 C) and pHopt. Major conclusions are: (i) Both Vmax and Km were log-normal distributed, with no significant difference in Vmax exhibited between enzymes originating from bacteria or fungi. (ii) No significant difference in Vmax was found between cellulases and ligninases; however, there was significant difference in Km between them. (iii) Ligninases had higher Ea values and lower pHopt than cellulases; average ratio of pHsen to pHopt ranged 0.3 0.4 for the five enzymes, which means that an increase or decrease of 1.1 1.7 pH units from pHopt would reduce Vmax by 50%. (iv) Our analysis indicated that the Vmax values from lab measurements with purified enzymes were 1 2 orders of magnitude higher than those for use in SOC decomposition models under field conditions.

  8. Kinetic Parameters of Binary Iron/Oxidant Pyrolants

    NASA Astrophysics Data System (ADS)

    Shamsipur, Mojtaba; Mahdi Pourmortazavi, Seied; Fathollahi, Manochehr

    2012-04-01

    The thermal properties of pyrotechnic mixtures containing iron powder as fuel and KNO3, KClO3, and KClO4 as oxidants are reported. The thermogravimetry-differential thermal analysis results for pure components and corresponding pyrotechnic mixtures revealed that the melting point, decomposition temperature, and rate of oxygen releasing of the oxidants have dominant effects on ignition reaction of the pyrotechnic mixtures. The apparent activation energy and activation parameters for the combustion processes were evaluated from the differential scanning calorimetry experiments. Based on the ignition temperatures obtained and the resulting kinetic data, the thermal reactivity of the pyrotechnic mixtures was found to decrease as in the order Fe + KClO3 > Fe + KNO3 > Fe + KClO4.

  9. Pyrolysis of Sawdust, Rice Husk and Sugarcane Bagasse: Kinetic Modeling and Estimation of Kinetic Parameters using Different Optimization Tools

    NASA Astrophysics Data System (ADS)

    Khonde, Ruta Dhanram; Chaurasia, Ashish Subhash

    2015-04-01

    The present study provides the kinetic model to describe the pyrolysis of sawdust, rice-husk and sugarcane bagasse as biomass. The kinetic scheme used for modelling of primary pyrolysis consisting of the two parallel reactions giving gaseous volatiles and solid char. Estimation of kinetic parameters for pyrolysis process has been carried out for temperature range of 773-1,173 K. As there are serious issues regarding non-convergence of some of the methods or solutions converging to local-optima, the proposed kinetic model is optimized to predict the best values of kinetic parameters for the system using three approaches—Two-dimensional surface fitting non-linear regression technique, MS-Excel Solver Tool and COMSOL software. The model predictions are in agreement with experimental data over a wide range of pyrolysis conditions. The estimated value of kinetic parameters are compared with earlier researchers and found to be matching well.

  10. Unscented Kalman filter with parameter identifiability analysis for the estimation of multiple parameters in kinetic models.

    PubMed

    Baker, Syed Murtuza; Poskar, C Hart; Junker, Björn H

    2011-01-01

    In systems biology, experimentally measured parameters are not always available, necessitating the use of computationally based parameter estimation. In order to rely on estimated parameters, it is critical to first determine which parameters can be estimated for a given model and measurement set. This is done with parameter identifiability analysis. A kinetic model of the sucrose accumulation in the sugar cane culm tissue developed by Rohwer et al. was taken as a test case model. What differentiates this approach is the integration of an orthogonal-based local identifiability method into the unscented Kalman filter (UKF), rather than using the more common observability-based method which has inherent limitations. It also introduces a variable step size based on the system uncertainty of the UKF during the sensitivity calculation. This method identified 10 out of 12 parameters as identifiable. These ten parameters were estimated using the UKF, which was run 97 times. Throughout the repetitions the UKF proved to be more consistent than the estimation algorithms used for comparison. PMID:21989173

  11. MPC for LPV systems with bounded parameter variations

    NASA Astrophysics Data System (ADS)

    Jungers, Marc; Oliveira, Ricardo C. L. F.; Peres, Pedro L. D.

    2011-01-01

    This article deals with the model predictive control (MPC) design problem for systems which are linearly dependent on a time-varying parameter. The main novelty is that, motivated by practical issues, the bounds on the rate of variation of the parameters are taken into account in the control design. Moreover, a Lyapunov function depending multiaffinely on the parameters computed at a set of instants of time and a parameter-dependent control gain are used to provide an upper bound to a quadratic performance index. The solution is obtained by means of a semidefinite programming algorithm. Examples illustrate the efficiency of the proposed approach.

  12. Kinetic parameters of uracil dosimeter in simulated extraterrestrial UV radiation

    NASA Astrophysics Data System (ADS)

    Kovács, G.; Gróf, P.; Bérces, A.; Patel, M. R.; Lammer, H.; Rontó, Gy.

    Studies of the solar UV environment on Earth 2.0 Gyr to 3.8 Gyr ago suggest that the terrestrial atmosphere was essentially anoxic, resulting in an ozone column abundance insufficient for protecting the planetary surface in the UV-B (280 nm - 315 nm) and the UV-C (200 nm - 280 nm) ranges. Since, short wavelength solar UV radiation in the UV-B and UV-C range penetrated through the atmosphere to the unprotected early Earth's surface, associated biological consequences may be expected. We discuss experimental data obtained as follows: Radiation sources applied were solar simulator and high power deuterium lamp, the wavelength were adjusted by interference filters (210, 230, 250 nm) and the irradiances were measured by OL754 spectroradiometer. The photo-reverse effect depends highly on the wavelength of the exposed radiation. Shorter wavelength UV radiation of about 200 nm is strongly effective in monomerization, while the longer wavelengths prefer the production of dimerization. In case of polychromatic light, like in space or on a planetary surface which is unprotected by an ozone layer the two processes run parallel. We could demonstrate experimentally, for the case of a uracil thin-layer that the photo-reaction process of the nucleotides can be both dimerization and the reverse process: monomerization. These results are important for the study of solar UV effects on organisms in the early terrestrial environment as well as for the search for life on Mars since we can show that biological harmful effects can also be reduced by shorter wavelength UV radiation, which is of importance in reducing DNA damages provoked by wavelengths longer than about 240 nm. Our earlier results showed that dimerization of the pyrimidin base uracil can be described by a first order kinetics, and this reaction gives the possibility to determine the dose of the UV source applied. This work is a theoretical and experimental approach to the relevant parameters of the first order kinetics.

  13. Pseudohyphal variations of yeasts exposed to specific space flight parameters.

    PubMed

    Volz, P A; Hunter, R L

    1998-01-01

    Phenotypes of Saccharomyces cerevisiae and Rhodotorula rubra exposed to specific parameters of space flight, which were measured both quantitatively and qualitatively, produced variations in pseudohyphal formation. Both the length of the parent and branch psuedohyphal filaments varied according to specific wavelengths and energy levels of UV light exposures when phenotypic isolates were compared with the parent or ground control isolate of each yeast species. PMID:9881461

  14. Additional Investigations of Ice Shape Sensitivity to Parameter Variations

    NASA Technical Reports Server (NTRS)

    Miller, Dean R.; Potapczuk, Mark G.; Langhals, Tammy J.

    2006-01-01

    A second parameter sensitivity study was conducted at the NASA Glenn Research Center's Icing Research Tunnel (IRT) using a 36 in. chord (0.91 m) NACA-0012 airfoil. The objective of this work was to further investigate the feasibility of using ice shape feature changes to define requirements for the simulation and measurement of SLD and appendix C icing conditions. A previous study concluded that it was feasible to use changes in ice shape features (e.g., ice horn angle, ice horn thickness, and ice shape mass) to detect relatively small variations in icing spray condition parameters (LWC, MVD, and temperature). The subject of this current investigation extends the scope of this previous work, by also examining the effect of icing tunnel spray-bar parameter variations (water pressure, air pressure) on ice shape feature changes. The approach was to vary spray-bar water pressure and air pressure, and then evaluate the effects of these parameter changes on the resulting ice shapes. This paper will provide a description of the experimental method, present selected experimental results, and conclude with an evaluation of these results.

  15. Sensitivity of acoustic predictions to variation of input parameters

    NASA Technical Reports Server (NTRS)

    Brentner, Kenneth S.; Burley, Casey L.; Marcolini, Michael A.

    1994-01-01

    Rotor noise prediction codes predict the thickness and loading noise produced by a helicopter rotor, given the blade motion, rotor operating conditions, and fluctuating force distribution over the blade surface. However, the criticality of these various inputs, and their respective effects on the predicted acoustic field, have never been fully addressed. This paper examines the importance of these inputs, and the sensitivity of the acoustic predicitions to a variation of each parameter. The effects of collective and cyclic pitch, as well as coning and cyclic flapping, are presented. Blade loading inputs are examined to determine the necessary spatial and temporal resolution, as well as the importance of the chordwise distribution. The acoustic predictions show regions in the acoustic field where significant errors occur when simplified blade motions or blade loadings are used. An assessment of the variation in the predicted acoustic field is balanced by a consideration of Central Processing Unit (CPU) time necessary for the various approximations.

  16. Sensitivity of acoustic predictions to variation of input parameters

    NASA Technical Reports Server (NTRS)

    Brentner, Kenneth S.; Marcolini, Michael A.; Burley, Casey L.

    1991-01-01

    The noise prediction code WOPWOP predicts the thickness and loading noise produced by a helicopter rotor, given the blade motion, rotor operating conditions, and fluctuating force distribution over the blade surface. However, the criticality of these various inputs, and their respective effects on the predicted acoustic field, have never been fully addressed. This paper examines the importance of these inputs, and the sensitivity of the acoustic predictions to a variation of each parameter. The effects of collective and cyclic pitch, as well as coning and flapping, are presented. Blade loading inputs are examined to determine the necessary spatial and temporal resolution, as well as the importance of the cordwise distribution. The acoustic predictions show regions in the acoustic field where significant errors occur when simplified blade motions or blade loadings are used. An assessment of the variation in the predicted acoustic field is balanced by a consideration of CPU time necessary for the various approximations.

  17. Computation of photovoltaic parameters under lunar temperature variation

    NASA Technical Reports Server (NTRS)

    Dhere, Neelkanth G.; Santiago, James V.

    1993-01-01

    Photovoltaic (PV) arrays with regenerative-fuel-cell energy storage is a prime, power-system candidate for lunar photo-power. The PV module performance decreases at higher temperatures. Surface temperature variations of the moon are extreme, the maximum (noon) temperature being 384 K. The present work utilizes detailed computations of photovoltaic parameters with computer program developed earlier for the computation of optimum bandgaps of single- and two-junction solar cells at different temperatures, and calculates the power output of single and two-junction solar modules under different configurations which constitutes an improvement over the assumption of a linear variation of efficiency with temperature. The program also calculates the necessary PV-array size to satisfy stipulated levels of day- and night-time power consumption.

  18. Describing variations of the Fisher-matrix across parameter space

    NASA Astrophysics Data System (ADS)

    Schäfer, Björn Malte; Reischke, Robert

    2016-08-01

    Forecasts in cosmology, both with Monte Carlo Markov-chain methods and with the Fisher-matrix formalism, depend on the choice of the fiducial model because both the signal strength of any observable and the model non-linearities linking observables to cosmological parameters vary in the general case. In this paper we propose a method for extrapolating Fisher-forecasts across the space of cosmological parameters by constructing a suitable basis. We demonstrate the validity of our method with constraints on a standard dark energy model extrapolated from a ΛCDM-model, as can be expected from two-bin weak lensing tomography with an Euclid-like survey, in the parameter pairs (Ωm, σ8), (Ωm, w0) and (w0, wa). Our numerical results include very accurate extrapolations across a wide range of cosmological parameters in terms of shape, size and orientation of the parameter likelihood, and a decomposition of the change of the likelihood contours into modes, which are straightforward to interpret in a geometrical way. We find that in particular the variation of the dark energy figure of merit is well captured by our formalism.

  19. Parameter Estimates in Differential Equation Models for Chemical Kinetics

    ERIC Educational Resources Information Center

    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…

  20. Differential scanning calorimetry in determining kinetics parameter of Si oxidation

    NASA Astrophysics Data System (ADS)

    Faruque, Sk. Abdul Kader Md.; Chakraborty, Supratic

    2016-05-01

    Differential scanning calorimetry (DSC) technique is employed here to study the oxidation of silicon by solid-gas reaction at a constant heating rate. The diffusion coefficient of oxygen into silicon at 900 °C is estimated from the kinetic equation of 1-dimensional diffusion controlled growth. The diffusion coefficient, D estimated as 4.5 × 10-5 exp (1.01ev/κBT) m2/s, as is in well agreement with the standard value available in literature.

  1. Anisotropic parameter estimation using velocity variation with offset analysis

    SciTech Connect

    Herawati, I.; Saladin, M.; Pranowo, W.; Winardhie, S.; Priyono, A.

    2013-09-09

    Seismic anisotropy is defined as velocity dependent upon angle or offset. Knowledge about anisotropy effect on seismic data is important in amplitude analysis, stacking process and time to depth conversion. Due to this anisotropic effect, reflector can not be flattened using single velocity based on hyperbolic moveout equation. Therefore, after normal moveout correction, there will still be residual moveout that relates to velocity information. This research aims to obtain anisotropic parameters, ε and δ, using two proposed methods. The first method is called velocity variation with offset (VVO) which is based on simplification of weak anisotropy equation. In VVO method, velocity at each offset is calculated and plotted to obtain vertical velocity and parameter δ. The second method is inversion method using linear approach where vertical velocity, δ, and ε is estimated simultaneously. Both methods are tested on synthetic models using ray-tracing forward modelling. Results show that δ value can be estimated appropriately using both methods. Meanwhile, inversion based method give better estimation for obtaining ε value. This study shows that estimation on anisotropic parameters rely on the accuracy of normal moveout velocity, residual moveout and offset to angle transformation.

  2. k-Cone analysis: determining all candidate values for kinetic parameters on a network scale.

    PubMed

    Famili, Iman; Mahadevan, Radhakrishnan; Palsson, Bernhard O

    2005-03-01

    The absence of comprehensive measured kinetic values and the observed inconsistency in the available in vitro kinetic data has hindered the formulation of network-scale kinetic models of biochemical reaction networks. To meet this challenge we present an approach to construct a convex space, termed the k-cone, which contains all the allowable numerical values of the kinetic constants in large-scale biochemical networks. The definition of the k-cone relies on the incorporation of in vivo concentration data and a simplified approach to represent enzyme kinetics within an established constraint-based modeling approach. The k-cone approach was implemented to define the allowable combination of numerical values for a full kinetic model of human red blood cell metabolism and to study its correlated kinetic parameters. The k-cone approach can be used to determine consistency between in vitro measured kinetic values and in vivo concentration and flux measurements when used in a network-scale kinetic model. k-Cone analysis was successful in determining whether in vitro measured kinetic values used in the reconstruction of a kinetic-based model of Saccharomyces cerevisiae central metabolism could reproduce in vivo measurements. Further, the k-cone can be used to determine which numerical values of in vitro measured parameters are required to be changed in a kinetic model if in vivo measured values are not reproduced. k-Cone analysis could identify what minimum number of in vitro determined kinetic parameters needed to be adjusted in the S. cerevisiae model to be consistent with the in vivo data. Applying the k-cone analysis a priori to kinetic model development may reduce the time and effort involved in model building and parameter adjustment. With the recent developments in high-throughput profiling of metabolite concentrations at a whole-cell scale and advances in metabolomics technologies, the k-cone approach presented here may hold the promise for kinetic

  3. k-Cone Analysis: Determining All Candidate Values for Kinetic Parameters on a Network Scale

    PubMed Central

    Famili, Iman; Mahadevan, Radhakrishnan; Palsson, Bernhard O.

    2005-01-01

    The absence of comprehensive measured kinetic values and the observed inconsistency in the available in vitro kinetic data has hindered the formulation of network-scale kinetic models of biochemical reaction networks. To meet this challenge we present an approach to construct a convex space, termed the k-cone, which contains all the allowable numerical values of the kinetic constants in large-scale biochemical networks. The definition of the k-cone relies on the incorporation of in vivo concentration data and a simplified approach to represent enzyme kinetics within an established constraint-based modeling approach. The k-cone approach was implemented to define the allowable combination of numerical values for a full kinetic model of human red blood cell metabolism and to study its correlated kinetic parameters. The k-cone approach can be used to determine consistency between in vitro measured kinetic values and in vivo concentration and flux measurements when used in a network-scale kinetic model. k-Cone analysis was successful in determining whether in vitro measured kinetic values used in the reconstruction of a kinetic-based model of Saccharomyces cerevisiae central metabolism could reproduce in vivo measurements. Further, the k-cone can be used to determine which numerical values of in vitro measured parameters are required to be changed in a kinetic model if in vivo measured values are not reproduced. k-Cone analysis could identify what minimum number of in vitro determined kinetic parameters needed to be adjusted in the S. cerevisiae model to be consistent with the in vivo data. Applying the k-cone analysis a priori to kinetic model development may reduce the time and effort involved in model building and parameter adjustment. With the recent developments in high-throughput profiling of metabolite concentrations at a whole-cell scale and advances in metabolomics technologies, the k-cone approach presented here may hold the promise for kinetic

  4. Estimation of kinetic parameters related to biochemical interactions between hydrogen peroxide and signal transduction proteins

    PubMed Central

    Brito, Paula M.; Antunes, Fernando

    2014-01-01

    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 toward 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 underlie the interplay between oxidative stress and redox signaling responses. PMID:25325054

  5. A Sight on the Variation of Spectral Parameters in GRBs

    SciTech Connect

    Hafizi, Mimoza; Boci, Sonila

    2010-01-21

    Gamma ray bursts (GRBs) are high energy photons detected during a short interval of time. They are signs of the most energetic events in the universe. Photons detected show a non thermal spectrum, very well described by the peak energy and two smoothly connected power laws with different slopes or indices. This spectrum is named Band spectrum and serves actually as the most important source of information on their physical origin. It characterizes not only the overall emission, but also the instantaneous one, found in small successive intervals of time during the event. The time-resolved spectra show an obvious evolution in energy, which is generally accepted and supported by several arguments. There is also some evidence in measuring a kind of evolution in slope parameters, which would be considered as a serious source of information for the physical mechanism. In this work we try to examine the limit in observation bands, which we suspect as a reason for the apparent variation in time of spectral indices. Our work is based on a numeric and certified code. We simulate GRBs assuming synchrotron emission in the internal shocks model. For each time-resolved spectrum we find spectral parameters based on the Band function.

  6. Further examples of seasonal variations of ELF radio propagation parameters

    NASA Astrophysics Data System (ADS)

    Bannister, Peter R.

    1999-01-01

    In this paper we use experimentally determined values of effective attenuation rate, excitation factor, and relative phase velocity, along with the theoretical expressions derived by C. and P. Greifinger, to establish the seasonal variation of representative ionospheric conductivity parameters. These parameters include the reflection heights h0 and h1 (or hE), inverse scale height β, and reference height H. The basis for this analysis is provided by the 1990-1992 76-Hz field strength measurements taken at four land-based ELF monitoring sites established by the U.S. Navy. The source for these measurements was the U.S. Navy's dual-antenna transmitting system (WTF/MTF). The main conclusion of this paper is that the summertime and January nighttime attenuation rates are substantially lower than during other times of the year. This nighttime attenuation rate decrease appears to be mainly due to an increase in the inverse scale height β, rather than to an increase in the reflection heights h0 and hE.

  7. Determining the Kinetic Parameters Characteristic of Microalgal Growth.

    ERIC Educational Resources Information Center

    Martinez Sancho, Maria Eugenie; And Others

    1991-01-01

    An activity in which students obtain a growth curve for algae, identify the exponential and linear growth phases, and calculate the parameters which characterize both phases is described. The procedure, a list of required materials, experimental conditions, analytical technique, and a discussion of the interpretations of individual results are…

  8. Simulation of the interannual variations of aerosols in China: role of variations in meteorological parameters

    NASA Astrophysics Data System (ADS)

    Mu, Q.; Liao, H.

    2014-09-01

    We used the nested grid version of the global three-dimensional Goddard Earth Observing System chemical transport model (GEOS-Chem) to examine the interannual variations (IAVs) of aerosols over heavily polluted regions in China for years 2004-2012. The role of variations in meteorological parameters was quantified by a simulation with fixed anthropogenic emissions at year 2006 levels and changes in meteorological parameters over 2004-2012. Simulated PM2.5 (particles with a diameter of 2.5 μm or less) aerosol concentrations exhibited large IAVs in North China (NC; 32-42° N, 110-120° E), with regionally averaged absolute percent departure from the mean (APDM) values of 17, 14, 14, and 11% in December-January-February (DJF), March-April-May (MAM), June-July-August (JJA), and September-October-November (SON), respectively. Over South China (SC; 22-32° N, 110-120° E), the IAVs in PM2.5 were found to be the largest in JJA, with the regional mean APDM values of 14% in JJA and of about 9% in other seasons. The concentrations of PM2.5 over the Sichuan Basin (SCB; 27-33° N, 102-110° E) were simulated to have the smallest IAVs among the polluted regions examined in this work, with APDM values of 8-9% in all seasons. All aerosol species (sulfate, nitrate, ammonium, black carbon, and organic carbon) were simulated to have the largest IAVs over NC in DJF, corresponding to the large variations in meteorological parameters over NC in this season. Process analyses were performed to identify the key meteorological parameters that determined the IAVs of different aerosol species in different regions. While the variations in temperature and specific humidity, which influenced the gas-phase formation of sulfate, jointly determined the IAVs of sulfate over NC in both DJF and JJA, wind (or convergence of wind) in DJF and precipitation in JJA were the dominant meteorological factors to influence IAVs of sulfate over SC and the SCB. The IAVs in temperature and specific humidity

  9. Validity of repeated initial rise thermoluminescence kinetic parameter determinations

    SciTech Connect

    Kierstead, J.A.; Levy, P.W.

    1990-01-01

    The validity of thermoluminescence (TL) analysis by repeated initial rise measurements has been studied by computer simulation. Thermoluminescence described by 1st Order, 2nd Order, General One Trap and Interactive TL Kinetics was investigated. In the simulation each of the repeated temperature increase and decrease cycles contains a linear temperature increase followed by a decrease appropriate for radiative cooling, i.e. the latter is approximated by a decreasing exponential. The activation energies computed from the simulated emission are readily compared with those used to compute the TL emission. In all cases studied, the repeated initial rise technique provides reliable results only for single peak glow curves or for glow curves containing peaks that do not overlap and, if sufficiently separated, the lowest temperature peak in multipeak curves. Also the temperatures, or temperature cycles corresponding to correct activation energies occur on the low temperature side of the normal glow curve, often well below the peak temperature. A variety of misleading and/or incorrect results an be obtained when the repeated initial rise technique is applied to TL systems that produce overlapping peaks in the usual glow curve. 6 refs., 10 figs.

  10. Simultaneous determination of kinetic and thermodynamic parameters from fast-reaction kinetic measurements.

    PubMed

    Trimm, H H; Ushio, H; Patel, R C

    1981-10-01

    A combined stopped-flow temperature-jump apparatus interfaced with a dedicated microcomputer has been used to study the complexation reaction of iron(III) with thiocyanate in aqueous solution. Kinetic rate-constants (k(f) = 143 l.mole(-1) .sec(-1) from T-jump, k(f) = 150 l.mole(-1) .sec(-1) from stopped flow), equilibrium constants (K = 143 from T-jump, K = 150 from stopped flow) and the thermodynamic enthalpy change (DeltaH(c) = -6.7 kJ/mole) could be independently determined from the simultaneous application of the two techniques. PMID:18962997

  11. Inverse modeling approach for evaluation of kinetic parameters of a biofilm reactor using tabu search.

    PubMed

    Kumar, B Shiva; Venkateswarlu, Ch

    2014-08-01

    The complex nature of biological reactions in biofilm reactors often poses difficulties in analyzing such reactors experimentally. Mathematical models could be very useful for their design and analysis. However, application of biofilm reactor models to practical problems proves somewhat ineffective due to the lack of knowledge of accurate kinetic models and uncertainty in model parameters. In this work, we propose an inverse modeling approach based on tabu search (TS) to estimate the parameters of kinetic and film thickness models. TS is used to estimate these parameters as a consequence of the validation of the mathematical models of the process with the aid of measured data obtained from an experimental fixed-bed anaerobic biofilm reactor involving the treatment of pharmaceutical industry wastewater. The results evaluated for different modeling configurations of varying degrees of complexity illustrate the effectiveness of TS for accurate estimation of kinetic and film thickness model parameters of the biofilm process. The results show that the two-dimensional mathematical model with Edward kinetics (with its optimum parameters as mu(max)rho(s)/Y = 24.57, Ks = 1.352 and Ki = 102.36) and three-parameter film thickness expression (with its estimated parameters as a = 0.289 x 10(-5), b = 1.55 x 10(-4) and c = 15.2 x 10(-6)) better describes the biofilm reactor treating the industry wastewater. PMID:25306783

  12. Influence of the mutable kinetic parameters on the adhesion and debonding of thin viscoelastic films.

    PubMed

    Ghosh, Abir; Bandyopadhyay, Dipankar; Sharma, Ashutosh

    2016-09-01

    Detachment of a surface from a viscoelastic layer, such as a film of glue, engenders bridges between the surfaces until separation. Such surface instabilities arising during contact and detachment of viscoelastic films with rigid contactors have been theoretically explored by linear stability analysis and nonlinear simulations. The contact instabilities of viscoelastic materials are found to manifest in either a 'critical' or a 'dominant' mode in which the former is preferred when the contactor is slowly brought near the film while the latter manifests when the film is 'hard-pressed' against it. The nonlinear analysis considers the movement of contactor during adhesion-debonding cycle, which uncovers that the kinetic parameters can overshadow the thermodynamically predicted area of contact, average force for pull-off, energy of contactor-film separation, and pathways of debonding. Three distinct pathways of debonding - peeling, catastrophic column collapse, and column coalescence, are found to manifest with the variation in the ratio of the elastic to viscous compliances of the viscoelastic film. The study also reveals that in the dominant mode of instability, a smaller length scale with a larger area contact between the contactor and film can develop patterns having aspect ratio ∼10 times larger than the same obtained from elastic film. PMID:27254253

  13. Fuzzy Stochastic Petri Nets for Modeling Biological Systems with Uncertain Kinetic Parameters.

    PubMed

    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. PMID:26910830

  14. Fuzzy Stochastic Petri Nets for Modeling Biological Systems with Uncertain Kinetic Parameters

    PubMed Central

    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. PMID:26910830

  15. Solid State Kinetic Parameters and Chemical Mechanism of the Dehydration of CoCl2.6H2O.

    ERIC Educational Resources Information Center

    Ribas, Joan; And Others

    1988-01-01

    Presents an experimental example illustrating the most common methods for the determination of kinetic parameters. Discusses the different theories and equations to be applied and the mechanism derived from the kinetic results. (CW)

  16. Longitudinal variations in fitting parameters for adult cochlear implant recipients.

    PubMed

    Mosca, F; Grassia, R; Leone, C A

    2014-04-01

    In patients with a cochlear implant (CI), the first critical point in processing auditory information from sound stimuli that leads to comprehension is the interface between the electrode and the cochlear nerve, which is dependent on providing appropriate current input. The purpose of this work was to evaluate the longitudinal differences in psychoacoustic fitting parameters in CI users. We studied 26 profoundly deaf adults, aged between 18 and 58 years, who had been implanted in our department between 2009 and 2011. The lowest current levels that evoked an auditory sensation (T-level) and the highest current levels that did not elicit an uncomfortable loud sensation (C-level) were recorded at the time of activation, approximately 30 days after implantation (mean 28.5 days) (T0), after one month (T1), 3 months (T3), 6 months (T6) and one year (T12). Impedance values were calculated for electrode groups: basal, middle and apical. In all cases, the same model of perimodiolar implant (Cochlear™ Nucleus(®) CI24RE) and the same surgical technique (cochleostomy) were used. The values of T-level and C-level showed significant incremental changes between T0 and T1 and between T1 and T3. T-levels in the basal regions of the cochlea were higher than in other sites. T-levels in the basal turn exhibited higher values consistent with a greater amount of fibrosis, as reported in other studies. Our findings suggest that fitting sessions should be scheduled more frequently during the first three months as indicated by the greater slope of T- and C- level variations during that time frame. PMID:24843221

  17. Variational methods to estimate terrestrial ecosystem model parameters

    NASA Astrophysics Data System (ADS)

    Delahaies, Sylvain; Roulstone, Ian

    2016-04-01

    Carbon is at the basis of the chemistry of life. Its ubiquity in the Earth system is the result of complex recycling processes. Present in the atmosphere in the form of carbon dioxide it is adsorbed by marine and terrestrial ecosystems and stored within living biomass and decaying organic matter. Then soil chemistry and a non negligible amount of time transform the dead matter into fossil fuels. Throughout this cycle, carbon dioxide is released in the atmosphere through respiration and combustion of fossils fuels. Model-data fusion techniques allow us to combine our understanding of these complex processes with an ever-growing amount of observational data to help improving models and predictions. The data assimilation linked ecosystem carbon (DALEC) model is a simple box model simulating the carbon budget allocation for terrestrial ecosystems. Over the last decade several studies have demonstrated the relative merit of various inverse modelling strategies (MCMC, ENKF, 4DVAR) to estimate model parameters and initial carbon stocks for DALEC and to quantify the uncertainty in the predictions. Despite its simplicity, DALEC represents the basic processes at the heart of more sophisticated models of the carbon cycle. Using adjoint based methods we study inverse problems for DALEC with various data streams (8 days MODIS LAI, monthly MODIS LAI, NEE). The framework of constraint optimization allows us to incorporate ecological common sense into the variational framework. We use resolution matrices to study the nature of the inverse problems and to obtain data importance and information content for the different type of data. We study how varying the time step affect the solutions, and we show how "spin up" naturally improves the conditioning of the inverse problems.

  18. A novel method for measuring the concentration of chloroform based on kinetic parameters at atmosphere

    NASA Astrophysics Data System (ADS)

    Wang, Yuguo; Han, Haiyan; Chang, Tao; Liu, Xiuhong; Zhu, Qiaofen; Liu, Feng; Yan, Yongliang; Shen, Chengyin; Chu, Yannan

    2016-06-01

    A novel method is proposed to detect chloroform concentrations based on the kinetic parameters using ion mobility spectrometer with a negative corona discharge ion source operating at atmospheric pressure. Unlike conventional sample introduction mode, in this technique, CHCl3 enters into the drift tube from the end of drift region carried by the drift gas. There are two tails before Cl- and (CHCl3)·Cl- ion peaks, which fit to the ions formed in the drift region. Utilizing the kinetic parameters, concentration for CHCl3 can be calculated. This method not only offers a new way to get concentrations of CHCl3 under atmospheric pressure.

  19. Evaluation of Anaerobic Biofilm Reactor Kinetic Parameters Using Ant Colony Optimization.

    PubMed

    Satya, Eswari Jujjavarapu; Venkateswarlu, Chimmiri

    2013-09-01

    Fixed bed reactors with naturally attached biofilms are increasingly used for anaerobic treatment of industry wastewaters due their effective treatment performance. The complex nature of biological reactions in biofilm processes often poses difficulty in analyzing them experimentally, and mathematical models could be very useful for their design and analysis. However, effective application of biofilm reactor models to practical problems suffers due to the lack of knowledge of accurate kinetic models and uncertainty in model parameters. In this work, an inverse modeling approach based on ant colony optimization is proposed and applied to estimate the kinetic and film thickness model parameters of wastewater treatment process in an anaerobic fixed bed biofilm reactor. Experimental data of pharmaceutical industry wastewater treatment process are used to determine the model parameters as a consequence of the solution of the rigorous mathematical models of the process. Results were evaluated for different modeling configurations derived from the combination of mathematical models, kinetic expressions, and optimization algorithms. Analysis of results showed that the two-dimensional mathematical model with Haldane kinetics better represents the pharmaceutical wastewater treatment in the biofilm reactor. The mathematical and kinetic modeling of this work forms a useful basis for the design and optimization of industry wastewater treating biofilm reactors. PMID:24065871

  20. Evaluation of Anaerobic Biofilm Reactor Kinetic Parameters Using Ant Colony Optimization

    PubMed Central

    Satya, Eswari Jujjavarapu; Venkateswarlu, Chimmiri

    2013-01-01

    Abstract Fixed bed reactors with naturally attached biofilms are increasingly used for anaerobic treatment of industry wastewaters due their effective treatment performance. The complex nature of biological reactions in biofilm processes often poses difficulty in analyzing them experimentally, and mathematical models could be very useful for their design and analysis. However, effective application of biofilm reactor models to practical problems suffers due to the lack of knowledge of accurate kinetic models and uncertainty in model parameters. In this work, an inverse modeling approach based on ant colony optimization is proposed and applied to estimate the kinetic and film thickness model parameters of wastewater treatment process in an anaerobic fixed bed biofilm reactor. Experimental data of pharmaceutical industry wastewater treatment process are used to determine the model parameters as a consequence of the solution of the rigorous mathematical models of the process. Results were evaluated for different modeling configurations derived from the combination of mathematical models, kinetic expressions, and optimization algorithms. Analysis of results showed that the two-dimensional mathematical model with Haldane kinetics better represents the pharmaceutical wastewater treatment in the biofilm reactor. The mathematical and kinetic modeling of this work forms a useful basis for the design and optimization of industry wastewater treating biofilm reactors. PMID:24065871

  1. A Comparison of Isoconversional and Model-Fitting Approaches to Kinetic Parameter Estimation and Application Predictions

    SciTech Connect

    Burnham, A K

    2006-05-17

    Chemical kinetic modeling has been used for many years in process optimization, estimating real-time material performance, and lifetime prediction. Chemists have tended towards developing detailed mechanistic models, while engineers have tended towards global or lumped models. Many, if not most, applications use global models by necessity, since it is impractical or impossible to develop a rigorous mechanistic model. Model fitting acquired a bad name in the thermal analysis community after that community realized a decade after other disciplines that deriving kinetic parameters for an assumed model from a single heating rate produced unreliable and sometimes nonsensical results. In its place, advanced isoconversional methods (1), which have their roots in the Friedman (2) and Ozawa-Flynn-Wall (3) methods of the 1960s, have become increasingly popular. In fact, as pointed out by the ICTAC kinetics project in 2000 (4), valid kinetic parameters can be derived by both isoconversional and model fitting methods as long as a diverse set of thermal histories are used to derive the kinetic parameters. The current paper extends the understanding from that project to give a better appreciation of the strengths and weaknesses of isoconversional and model-fitting approaches. Examples are given from a variety of sources, including the former and current ICTAC round-robin exercises, data sets for materials of interest, and simulated data sets.

  2. Determination of Kinetic Parameters within a Single Nonisothermal On-Flow Experiment by Nanoliter NMR Spectroscopy.

    PubMed

    Gomez, M Victoria; Rodriguez, Antonio M; de la Hoz, Antonio; Jimenez-Marquez, Francisco; Fratila, Raluca M; Barneveld, Peter A; Velders, Aldrik H

    2015-10-20

    Conventional methods to determine the kinetic parameters for a certain reaction require multiple, separate isothermal experiments, resulting in time- and material-consuming processes. Here, an approach to determine the kinetic information within a single nonisothermal on-flow experiment is presented, consuming less than 10 μmol of reagents and having a total measuring time of typically 10 min. This approach makes use of a microfluidic NMR chip hyphenated to a continuous-flow microreactor and is based on the capabilities of the NMR chip to analyze subnanomole quantities of material in the 25 nL detection volume. Importantly, useful data are acquired from the microreactor platform in specific isothermal and nonisothermal frames. A model fitting the experimental data enables rapid determination of kinetic parameters, as demonstrated for a library of isoxazole and pyrazole derivatives. PMID:26383715

  3. The geomagnetic secular variation S parameter: A mathematical artifact

    NASA Astrophysics Data System (ADS)

    Linder, J. M.; Gilder, S. A.

    2011-12-01

    Secular variation, the change in the Earth's magnetic field through time, reflects the energy state of the geodynamo. Secular variation is commonly quantified by the standard deviation of the angular distances of the virtual geomagnetic poles to their mean pole, known as the S value. The S value has long been thought to exhibit latitude dependence [S(λ)] whose origin is widely attributed to a combination of time-varying dipole and non-dipole components. The slope, magnitude and uncertainty of S(λ) are taken as a basis to model the geomagnetic field and understand its evolution. Here we show that variations in S stem from a mathematical aberration of the conversion from directions to poles. A new method to quantify secular variation is proposed.

  4. Kinetic Parameters for the Noncatalyzed and Enzyme-Catalyzed Mutarotation of Glucose Using a Blood Glucometer

    ERIC Educational Resources Information Center

    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…

  5. Combined Yamamoto approach for simultaneous estimation of adsorption isotherm and kinetic parameters in ion-exchange chromatography.

    PubMed

    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. PMID:26306913

  6. Identification of random variation in structures and their parameter estimates.

    SciTech Connect

    Farrar, C. R.; Aumann, R. J.; McCarty, A. A.; Olson, C. C.

    2002-01-01

    Structures that are members of an ensemble of nominally identical systems actually differ due to variations in details among individuals. Furthermore, there are variations in the system response of an individual structure that can be attributed to unmeasured conditions (such as temperature and humidity) that are present during experiments. Finally, noise is present in all measurements of structural excitations and responses. For these reasons, there is always random variation associated with the characterizations of structural dynamic systems, and descriptions of results must be in statistical or probabilistic terms;. This study identifies and assesses the sources and the degrees of randomness in a metric of structural dynamics of a given system through experiments and analysis.

  7. Comparison of gasification kinetics parameters of different types of nuclear graphite

    SciTech Connect

    El-Genk, M. S.; Tournier, J. M. P.

    2012-07-01

    A chemical-reaction kinetics model of nuclear graphite gasification has recently been developed and successfully validated with gasification rate measurements for nuclear graphite grades of IG-110, IG-430, NBG-18 and NBG-25. The model employs 4 elementary chemical reactions with applicable parameters, including the values and Gaussian-like distributions of the specific activation energies, the pre-exponential coefficients for adsorption of oxygen and desorption of CO and CO{sub 2} gases, and the surface area of free active sites. These parameters are determined from the reported measurements of the total gasification and transient weight loss using a multi-parameter optimization algorithm. The determined chemical kinetics parameters for IG-100 and NB-25 are nearly the same, but slightly different from those for NBG-18 and IG-430. The initial specific area of free active sites is inversely proportional to the square root of the mass or volume of the graphite specimens used in experiments. The recommended chemical kinetics parameters in this paper for these grades of nuclear graphite should be applicable to future safety analysis of high-temperature gas cooled reactors in the unlikely event of a massive air ingress accident. (authors)

  8. Thermal kinetic and dielectric parameters of acenaphthene crystal grown by vertical Bridgman technique

    NASA Astrophysics Data System (ADS)

    Karuppusamy, S.; Dinesh Babu, K.; Nirmal Kumar, V.; Gopalakrishnan, R.

    2016-05-01

    The bulk acenaphthene crystal was grown in a single-wall ampoule by vertical Bridgman technique. X-ray diffraction analysis confirmed the orthorhombic crystal system of title compound with space group Pcm21. Thermal behavior of compound was studied using thermogravimetry—differential scanning calorimetry analysis. Thermal kinetic parameters like activation energy, frequency factor, Avrami exponent, reaction rate and degree of conversion were calculated using Kissingers and Ozawa methods under non-isothermal condition for acenaphthene crystal and reported for the first time. The calculated thermal kinetic parameters are presented. Dielectric studies were performed to calculate the dielectric parameters such as dielectric constant, dielectric loss, AC conductivity, and activation energy from Arrhenius plot.

  9. A compilation of rate parameters of water-mineral interaction kinetics for application to geochemical modeling

    USGS Publications Warehouse

    Palandri, James L.; Kharaka, Yousif K.

    2004-01-01

    Geochemical reaction path modeling is useful for rapidly assessing the extent of water-aqueous-gas interactions both in natural systems and in industrial processes. Modeling of some systems, such as those at low temperature with relatively high hydrologic flow rates, or those perturbed by the subsurface injection of industrial waste such as CO2 or H2S, must account for the relatively slow kinetics of mineral-gas-water interactions. We have therefore compiled parameters conforming to a general Arrhenius-type rate equation, for over 70 minerals, including phases from all the major classes of silicates, most carbonates, and many other non-silicates. The compiled dissolution rate constants range from -0.21 log moles m-2 s-1 for halite, to -17.44 log moles m-2 s-1 for kyanite, for conditions far from equilibrium, at 25 ?C, and pH near neutral. These data have been added to a computer code that simulates an infinitely well-stirred batch reactor, allowing computation of mass transfer as a function of time. Actual equilibration rates are expected to be much slower than those predicted by the selected computer code, primarily because actual geochemical processes commonly involve flow through porous or fractured media, wherein the development of concentration gradients in the aqueous phase near mineral surfaces, which results in decreased absolute chemical affinity and slower reaction rates. Further differences between observed and computed reaction rates may occur because of variables beyond the scope of most geochemical simulators, such as variation in grain size, aquifer heterogeneity, preferred fluid flow paths, primary and secondary mineral coatings, and secondary minerals that may lead to decreased porosity and clogged pore throats.

  10. Kinetic parameters for the thermal inactivation of quality-related enzymes in carrots and potatoes.

    PubMed

    Anthon, Gordon E; Barrett, Diane M

    2002-07-01

    Kinetic parameters for the thermal inactivation of several enzymes in carrot and potato homogenates have been determined. In carrots the most heat-resistant activity was polygalacturonase, followed by peroxidase and pectinmethylesterase. In potatoes peroxidase was the most resistant, followed by pectin methylesterase, polyphenol oxidase, and lipoxygenase. There were several notable similarities between the inactivation kinetics in the two vegetables. In both cases peroxidase activity gave simple first-order inactivation kinetics but yielded a curved Arrhenius plot for the temperature dependence. Pectin methylesterase in both commodities consisted of a labile and a resistant form. The relative amounts of the two forms and the temperature dependences for their inactivation were also similar. PMID:12083894

  11. Characterisation of sugar cane straw waste as pozzolanic material for construction: Calcining temperature and kinetic parameters

    SciTech Connect

    Frias, Moises

    2007-07-01

    This paper reports on the influence of calcining temperature (800 and 1000 deg. C) on the pozzolanic activation of sugar cane straw (SCS). The reaction kinetics of SCS ash-lime mixtures were inferred from physicochemical characteristics (X-ray diffraction patterns and thermogravimetry analysis. The fitting of a kinetic-diffusive model to the experimental data (fixed lime versus time) allowed the computing of the kinetic parameters (reaction rate constant) of the pozzolanic reaction. Results obtained confirm that the sugar cane straw ash (SCSA) calcined at 800 and 1000 deg. C have properties indicative of very high pozzolanic activity. No influence of calcining temperature on the pozzolanic activity was observed. Also, no crystalline compounds during the pozzolanic reaction were identified up to 90 days of reaction. Environmental durability and strength of the consequential mortars remain to be assessed.

  12. Systematic variational method for statistical nonlinear state and parameter estimation

    NASA Astrophysics Data System (ADS)

    Ye, Jingxin; Rey, Daniel; Kadakia, Nirag; Eldridge, Michael; Morone, Uriel I.; Rozdeba, Paul; Abarbanel, Henry D. I.; Quinn, John C.

    2015-11-01

    In statistical data assimilation one evaluates the conditional expected values, conditioned on measurements, of interesting quantities on the path of a model through observation and prediction windows. This often requires working with very high dimensional integrals in the discrete time descriptions of the observations and model dynamics, which become functional integrals in the continuous-time limit. Two familiar methods for performing these integrals include (1) Monte Carlo calculations and (2) variational approximations using the method of Laplace plus perturbative corrections to the dominant contributions. We attend here to aspects of the Laplace approximation and develop an annealing method for locating the variational path satisfying the Euler-Lagrange equations that comprises the major contribution to the integrals. This begins with the identification of the minimum action path starting with a situation where the model dynamics is totally unresolved in state space, and the consistent minimum of the variational problem is known. We then proceed to slowly increase the model resolution, seeking to remain in the basin of the minimum action path, until a path that gives the dominant contribution to the integral is identified. After a discussion of some general issues, we give examples of the assimilation process for some simple, instructive models from the geophysical literature. Then we explore a slightly richer model of the same type with two distinct time scales. This is followed by a model characterizing the biophysics of individual neurons.

  13. Systematic variational method for statistical nonlinear state and parameter estimation.

    PubMed

    Ye, Jingxin; Rey, Daniel; Kadakia, Nirag; Eldridge, Michael; Morone, Uriel I; Rozdeba, Paul; Abarbanel, Henry D I; Quinn, John C

    2015-11-01

    In statistical data assimilation one evaluates the conditional expected values, conditioned on measurements, of interesting quantities on the path of a model through observation and prediction windows. This often requires working with very high dimensional integrals in the discrete time descriptions of the observations and model dynamics, which become functional integrals in the continuous-time limit. Two familiar methods for performing these integrals include (1) Monte Carlo calculations and (2) variational approximations using the method of Laplace plus perturbative corrections to the dominant contributions. We attend here to aspects of the Laplace approximation and develop an annealing method for locating the variational path satisfying the Euler-Lagrange equations that comprises the major contribution to the integrals. This begins with the identification of the minimum action path starting with a situation where the model dynamics is totally unresolved in state space, and the consistent minimum of the variational problem is known. We then proceed to slowly increase the model resolution, seeking to remain in the basin of the minimum action path, until a path that gives the dominant contribution to the integral is identified. After a discussion of some general issues, we give examples of the assimilation process for some simple, instructive models from the geophysical literature. Then we explore a slightly richer model of the same type with two distinct time scales. This is followed by a model characterizing the biophysics of individual neurons. PMID:26651756

  14. Study of the kinetic parameters for synthesis and hydrolysis of pharmacologically active salicin isomer catalyzed by baker's yeast maltase

    NASA Astrophysics Data System (ADS)

    Veličković, D. V.; Dimitrijević, A. S.; Bihelović, F. J.; Jankov, R. M.; Milosavić, N.

    2011-12-01

    One of the key elements for understanding enzyme reactions is determination of its kinetic parameters. Since transglucosylation is kinetically controlled reaction, besides the reaction of synthesis, very important is the reaction of enzymatic hydrolysis of created product. Therefore, in this study, kinetic parameters for synthesis and secondary hydrolysis of pharmacologically active α isosalicin by baker's yeast maltase were calculated, and it was shown that specifity of maltase for hydrolysis is approximately 150 times higher then for synthesis.

  15. Thermoluminescence systems with two or more glow peaks described by anomalous kinetic parameters

    SciTech Connect

    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.

  16. A methodology for modeling photocatalytic reactors for indoor pollution control using previously estimated kinetic parameters.

    PubMed

    Passalía, Claudio; Alfano, Orlando M; Brandi, Rodolfo J

    2012-04-15

    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(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%. PMID:22030272

  17. Association between plasma zinc concentration and zinc kinetic parameters in premenopausal women.

    PubMed

    Yokoi, Katsuhiko; Egger, Norman G; Ramanujam, V M Sadagopa; Alcock, Nancy W; Dayal, Hari H; Penland, James G; Sandstead, Harold H

    2003-11-01

    The objective of this study was to measure relationships between plasma zinc (Zn) concentrations and Zn kinetic parameters and to measure relationships of Zn status with taste acuity, food frequency, and hair Zn in humans. The subjects were 33 premenopausal women not taking oral contraceptives and dietary supplements containing iron and Zn. Main outcomes were plasma Zn concentrations, Zn kinetic parameters based on the three-compartment mammillary model using 67Zn as a tracer, electrical taste detection thresholds, and food frequencies. Lower plasma Zn was significantly (P < 0.01) associated with smaller sizes of the central and the lesser peripheral Zn pools, faster disappearance of tracer from plasma, and higher transfer rate constants from the lesser peripheral pool to the central pool and from the central pool to the greater peripheral pool. The break points in the plasma Zn-Zn kinetics relationship were found between 9.94 and 11.5 micromol/l plasma Zn. Smaller size of the lesser peripheral pool was associated with lower frequency of beef consumption and higher frequency of bran breakfast cereal consumption. Hypozincemic women with plasma Zn <10.7 micromol/l or 700 ng/ml had decreased thresholds of electrical stimulation for gustatory nerves. Our results based on Zn kinetics support the conventional cutoff value of plasma Zn (10.7 micromol/l or 700 ng/ml) between normal and low Zn status. PMID:12865259

  18. Diurnal Variation of Meteorological Parameters in the Land Surface Interface

    NASA Astrophysics Data System (ADS)

    Pillai, J. S.

    A pilot land surface processes experiment was conducted at Anand, Gujarat, situated in the western part of India, from April to July 1995. The diurnal variation of air and soil temperature with respect to solar radiation was studied in two selected periods, one in summer and the other during monsoon. It was observed that during summer, there was a considerable lag in the temperature maxima with respect to solar radiation, as compared to the monsoon period. Also, in summer, when there was an increase in wind speed from near zero values in the early morning hours, the soil surface as well as the air temperature minima were raised.

  19. Effects of correlated parameters and uncertainty in electronic-structure-based chemical kinetic modelling.

    PubMed

    Sutton, Jonathan E; Guo, Wei; Katsoulakis, Markos A; Vlachos, Dionisios G

    2016-04-01

    Kinetic models based on first principles are becoming common place in heterogeneous catalysis because of their ability to interpret experimental data, identify the rate-controlling step, guide experiments and predict novel materials. To overcome the tremendous computational cost of estimating parameters of complex networks on metal catalysts, approximate quantum mechanical calculations are employed that render models potentially inaccurate. Here, by introducing correlative global sensitivity analysis and uncertainty quantification, we show that neglecting correlations in the energies of species and reactions can lead to an incorrect identification of influential parameters and key reaction intermediates and reactions. We rationalize why models often underpredict reaction rates and show that, despite the uncertainty being large, the method can, in conjunction with experimental data, identify influential missing reaction pathways and provide insights into the catalyst active site and the kinetic reliability of a model. The method is demonstrated in ethanol steam reforming for hydrogen production for fuel cells. PMID:27001728

  20. An investigation on the catalytic capacity of dolomite in transesterification and the calculation of kinetic parameters.

    PubMed

    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. PMID:24583217

  1. Effects of correlated parameters and uncertainty in electronic-structure-based chemical kinetic modelling

    NASA Astrophysics Data System (ADS)

    Sutton, Jonathan E.; Guo, Wei; Katsoulakis, Markos A.; Vlachos, Dionisios G.

    2016-04-01

    Kinetic models based on first principles are becoming common place in heterogeneous catalysis because of their ability to interpret experimental data, identify the rate-controlling step, guide experiments and predict novel materials. To overcome the tremendous computational cost of estimating parameters of complex networks on metal catalysts, approximate quantum mechanical calculations are employed that render models potentially inaccurate. Here, by introducing correlative global sensitivity analysis and uncertainty quantification, we show that neglecting correlations in the energies of species and reactions can lead to an incorrect identification of influential parameters and key reaction intermediates and reactions. We rationalize why models often underpredict reaction rates and show that, despite the uncertainty being large, the method can, in conjunction with experimental data, identify influential missing reaction pathways and provide insights into the catalyst active site and the kinetic reliability of a model. The method is demonstrated in ethanol steam reforming for hydrogen production for fuel cells.

  2. Nonlinear estimation of Monod growth kinetic parameters from a single substrate depletion curve.

    PubMed Central

    Robinson, J A; Tiedje, J M

    1983-01-01

    Monod growth kinetic parameters were estimated by fitting sigmoidal substrate depletion data to the integrated Monod equation, using nonlinear least-squares analysis. When the initial substrate concentration was in the mixed-order region, nonlinear estimation of simulated data sets containing known measurement errors provided accurate estimates of the mu max, Ks, and Y values used to create these data. Nonlinear regression analysis of sigmoidal substrate depletion data was also evaluated for H2-limited batch growth of Desulfovibrio sp. strain G11. The integrated Monod equation can be more convenient for the estimation of growth kinetic parameters, particularly for gaseous substrates, but it must be recognized that the estimates of mu max, Ks, and Y obtained may be influenced by the growth rate history of the inoculum. PMID:6870238

  3. Preliminary Investigation of Ice Shape Sensitivity to Parameter Variations

    NASA Technical Reports Server (NTRS)

    Miller, Dean R.; Potapczuk, Mark G.; Langhals, Tammy J.

    2005-01-01

    A parameter sensitivity study was conducted at the NASA Glenn Research Center's Icing Research Tunnel (IRT) using a 36 in. chord (0.91 m) NACA-0012 airfoil. The objective of this preliminary work was to investigate the feasibility of using ice shape feature changes to define requirements for the simulation and measurement of SLD icing conditions. It was desired to identify the minimum change (threshold) in a parameter value, which yielded an observable change in the ice shape. Liquid Water Content (LWC), drop size distribution (MVD), and tunnel static temperature were varied about a nominal value, and the effects of these parameter changes on the resulting ice shapes were documented. The resulting differences in ice shapes were compared on the basis of qualitative and quantitative criteria (e.g., mass, ice horn thickness, ice horn angle, icing limits, and iced area). This paper will provide a description of the experimental method, present selected experimental results, and conclude with an evaluation of these results, followed by a discussion of recommendations for future research.

  4. Semiannual variation of the geomagnetic activity and solar wind parameters

    NASA Astrophysics Data System (ADS)

    Orlando, M.; Moreno, G.; Parisi, M.; Storini, M.

    1993-10-01

    The semiannual variation of the geomagnetic activity is investigated in connection with a large set of solar wind and interplanetary magnetic field data (4494 daily averages from 1965 to 1987). Our analysis confirms that the geomagnetic activity (described by the aa index), is mainly modulated by the southward component of the magnetic field (BS), as suggested by Russell and McPherron. On the other hand, it is also found that the solar wind velocity (V) has a relevant role in this phenomenon. In fact, the amplitude of the aa modulation is best correlated with the function BSV2. We also explore the linkage between the annual trend of aa and the sunspot activity (1868-1989), showing that the modulation of the geomagnetic activity follows a more regular pattern during the descending phase of the solar cycle than during the rising and maximum parts.

  5. [Determination of kinetic parameters lymphocyte populations in cows with chronic lymphocytic leukemia].

    PubMed

    Kuznetsov, V A; Feofanova, T V; Busol, V A; Nikolaeva, N V

    1995-01-01

    We analyzed changes in the number of lymphocytes in the blood of cows with chronic lymphoid leukemia using the Gomperts equation of population dynamics. The parameters of this equation were determined. Coefficients beta and gamma proved to be the most variable. The former reflects the delay and the latter characterizes the maximum rate of growth of the lymphocyte population. According to these parameters, three groups of animals were distinguished with different kinetics of leucosis and different correlations between immuno-hematological indices. PMID:7670356

  6. Reliability of spatiotemporal and kinetic gait parameters determined by a new instrumented treadmill system

    PubMed Central

    2013-01-01

    Background Despite the emerging use of treadmills integrated with pressure platforms as outcome tools in both clinical and research settings, published evidence regarding the measurement properties of these new systems is limited. This study evaluated the within– and between–day repeatability of spatial, temporal and vertical ground reaction force parameters measured by a treadmill system instrumented with a capacitance–based pressure platform. Methods Thirty three healthy adults (mean age, 21.5 ± 2.8 years; height, 168.4 ± 9.9 cm; and mass, 67.8 ± 18.6 kg), walked barefoot on a treadmill system (FDM–THM–S, Zebris Medical GmbH) on three separate occasions. For each testing session, participants set their preferred pace but were blinded to treadmill speed. Spatial (foot rotation, step width, stride and step length), temporal (stride and step times, duration of stance, swing and single and double support) and peak vertical ground reaction force variables were collected over a 30–second capture period, equating to an average of 52 ± 5 steps of steady–state walking. Testing was repeated one week following the initial trial and again, for a third time, 20 minutes later. Repeated measures ANOVAs within a generalized linear modelling framework were used to assess between–session differences in gait parameters. Agreement between gait parameters measured within the same day (session 2 and 3) and between days (session 1 and 2; 1 and 3) were evaluated using the 95% repeatability coefficient. Results There were statistically significant differences in the majority (14/16) of temporal, spatial and kinetic gait parameters over the three test sessions (P < .01). The minimum change that could be detected with 95% confidence ranged between 3% and 17% for temporal parameters, 14% and 33% for spatial parameters, and 4% and 20% for kinetic parameters between days. Within–day repeatability was similar to that observed between days. Temporal

  7. Narrow-track wheeled agricultural tractor parameter variation.

    PubMed

    Guzzomi, A; Rondelli, V

    2013-10-01

    Despite a general consensus among farmers, manufacturers, and researchers that wheeled agricultural tractor design has changed over time, there is little published evidence. There is debate as to whether the standardized rollover protective structure (ROPS) energy and force requirements, based on a tractor reference mass and pertaining to studies conducted more than 40 years ago, are appropriate for modern tractors. This article investigated the physical parameters of 326 modern narrow-track tractors, measured according to OECD Code 6 over 16 years (1993 to 2008 inclusive): 252 (-77%) were fixed-chassis tractors and 74 (-23%) were articulated. To understand the significance of design changes, the data were analyzed with respect to time and as a function of tractor mass. Articulated and fixed-chassis data were treated separately. The time data allowed qualitative analysis, while the mass data allowed quantitative analysis. The parameters show some changes over time and clearly indicate differences between articulated and fixed-chassis types. The parameter changes, along with the differences between types, may have important safety ramifications for ROPS energy absorption requirements, and these aspects are discussed. Regression lines with R2 values were fitted to the mass-related data for fixed-chassis and articulated tractors to determine the suitability of fit. The mass relations also displayed differences between fixed-chassis and articulated tractors. Thus, the most significant recommendation from this study is that the standardized testing procedure for narrow-track wheeled agricultural tractor category should be split into two groups: fixed-chassis and articulated. PMID:24673034

  8. Kinetics of Bacterial Phospholipase C Activity at Micellar Interfaces: Effect of Substrate Aggregate Microstructure and a Model for the Kinetic Parameters

    PubMed Central

    Singh, Jasmeet; Ranganathan, Radha; Hajdu, Joseph

    2009-01-01

    Activity at micellar interfaces of bacterial phospholipase C from Bacillus cereus on phospholipids solubilized in micelles was investigated with the goal of elucidating the role of the interface microstructure and developing further an existing kinetic model. Enzyme kinetics and physicochemical characterization of model substrate aggregates were combined; thus enabling the interpretation of kinetics in the context of the interface. Substrates were diacylphosphatidylcholine of different acyl chain lengths in the form of mixed micelles with dodecyldimethylammoniopropanesulfonate. An early kinetic model, reformulated to reflect the interfacial nature of the kinetics, was applied to the kinetic data. A better method of data treatment is proposed, use of which makes the presence of microstructure effects quite transparent. Models for enzyme-micelle binding and enzyme-lipid binding are developed and expressions incorporating the microstructural properties are derived for the enzyme-micelle dissociation constant KS and the interface Michaelis-Menten constant, KM. Use of these expressions in the interface kinetic model brings excellent agreement between the kinetic data and the model. Numerical values for the thermodynamic and kinetic parameters are determined. Enzyme-lipid binding is found to be an activated process with an acyl chain length dependent free energy of activation that decreases with micelle lipid molar fraction with a coefficient of about −15 RT and correlates with the tightness of molecular packing in the substrate aggregate. Thus the physical insight obtained includes a model for the kinetic parameters that shows that these parameters depend on the substrate concentration and acyl chain length of the lipid. Enzyme-micelle binding is indicated to be hydrophobic and solvent mediated with a dissociation constant of 1.2 mM. PMID:19367944

  9. Optimization of kinetic parameters for the degradation of plasmid DNA in rat plasma

    NASA Astrophysics Data System (ADS)

    Chaudhry, Q. A.

    2014-12-01

    Biotechnology is a rapidly growing area of research work in the field of pharmaceutical sciences. The study of pharmacokinetics of plasmid DNA (pDNA) is an important area of research work. It has been observed that the process of gene delivery faces many troubles on the transport of pDNA towards their target sites. The topoforms of pDNA has been termed as super coiled (S-C), open circular (O-C) and linear (L), the kinetic model of which will be presented in this paper. The kinetic model gives rise to system of ordinary differential equations (ODEs), the exact solution of which has been found. The kinetic parameters, which are responsible for the degradation of super coiled, and the formation of open circular and linear topoforms have a great significance not only in vitro but for modeling of further processes as well, therefore need to be addressed in great detail. For this purpose, global optimization techniques have been adopted, thus finding the optimal results for the said model. The results of the model, while using the optimal parameters, were compared against the measured data, which gives a nice agreement.

  10. Kinetic parameters related to sources and sinks of vibrationally excited OH in the nightglow

    SciTech Connect

    McDade, I.C.; Llewellyn, E.J. )

    1987-07-01

    Kinetic parameters related to vibrational deactivation and chemical removal of vibrationally excited OH radicals in the mesosphere are deduced from ground-based measurements of the mean vibrational distribution of the OH Meinel bands in the nightglow. The derived parameters, which rely on a laboratory measured rate coefficient for the removal of OH(v = 9) by O{sub 2} and a set of relative Meinel band transition probabilities, have been obtained for two limiting Meinel band excitation models that differ in the extent to which single-quantum vibrational deactivation and sudden death' collisional removal processes determine the OH vibrational distribution. It is shown that the OH Meinel band emission can be adequately explained with the deduced parameters and the H + O{sub 3} {yields} OH + O{sub 2} reaction as the only chemical source of vibrationally excited OH. Evidence is presented which suggests that the reaction HO{sub 2} + O {leftrightarrow} HO + O{sub 2} may perhaps be involved as a sink of vibrationally excited OH rather than as a potential source. The deduced kinetic parameters should be particularly useful in future Meinel band studies as they have been obtained from an analysis for which there is no assumption about the very uncertain OH radiative lifetimes.

  11. Variation in the modal parameters of space structures

    NASA Technical Reports Server (NTRS)

    Crawley, Edward F.; Barlow, Mark S.; Van Schoor, Marthinus C.; Bicos, Andrew S.

    1992-01-01

    An analytic and experimental study of gravity and suspension influences on space structural test articles is presented. A modular test article including deployable, erectable, and rotary modules was assembled in three one- and two-dimensional structures. The two deployable modules utilized cable diagonal bracing rather than rigid cross members; within a bay of one of the deployable modules, the cable preload was adjustable. A friction lock was used on the alpha joint to either allow or prohibit rotary motion. Suspension systems with plunge fundamentals of 1, 2, and 5 Hz were used for ground testing to evaluate the influences of suspension stiffness. Assembly and reassembly testing was performed, as was testing on two separate shipsets at two test sites. Trends and statistical variances in modal parameters are presented as a function of force amplitude, joint preload, reassembly, shipset and suspension. Linear finite element modeling of each structure provided analytical results for 0-g unsuspended and 1-g suspended models, which are correlated with the analytical model.

  12. Wind Turbine Response to Analytic Inflow Vortex Parameters Variation: Preprint

    SciTech Connect

    Hand, M. M.; Robinson, M. C.; Balas, M. J.

    2003-11-01

    As larger wind turbines are placed on taller towers, rotors frequently operate in atmospheric conditions that support organized, coherent turbulent structures. It is hypothesized that these structures have a detrimental impact on the blade fatigue life experienced by the wind turbine. These structures are extremely difficult to identify with sophisticated anemometry such as ultra-sonic anemometers. In order to ascertain the idealized worst-case scenario for vortical inflow structures impinging on a wind turbine rotor, we created a simple, analytic vortex model. The Rankine vortex model assumes the vortex core undergoes solid body rotation to avoid a singularity at the vortex center and is surrounded by a 2-dimensional potential flow field. Using the wind turbine as a sensor and the FAST wind turbine dynamics code with limited degrees of freedom, we determined the aerodynamic loads imparted to the wind turbine by the vortex structure. The size, strength, rotational direction, plan e of rotation, and location of the vortex were varied over a wide range of operating parameters. We identified the vortex conformation with the most significant effect on blade root bending moment cycle amplitude. Vortices with radii on the scale of the rotor diameter or smaller caused blade root bending moment cyclic amplitudes that lead to reduced fatigue life. The rotational orientation, clockwise or counter-clockwise produces little difference in the bending moment response. Vortices in the XZ plane produce bending moment amplitudes significantly greater than vortices in the YZ plane. The response to vortices in the inflow is similar for both 2- and 3-blade turbines.

  13. Wind turbine response to parameter variation of analytic inflow vortices

    NASA Astrophysics Data System (ADS)

    Hand, M. Maureen; Robinson, Michael C.; Balas, Mark J.

    2006-05-01

    As larger wind turbines are placed on taller towers, rotors frequently operate in atmospheric conditions that support organized, coherent turbulent structures. It is hypothesized that these structures have a detrimental impact on the blade fatigue life experienced by the wind turbine. These structures are extremely difficult to identify with sophisticated anemometry such as ultrasonic anemometers. This study was performed to identify the vortex characteristics that contribute to high-amplitude cyclic blade loads, assuming that these vortices exist under certain atmospheric conditions. This study does not attempt to demonstrate the existence of these coherent turbulent structures. In order to ascertain the idealized worst-case scenario for vortical inflow structures impinging on a wind turbine rotor, we created a simple, analytic vortex model. The Rankine vortex model assumes that the vortex core undergoes solid body rotation to avoid a singularity at the vortex centre and is surrounded by a two-dimensional potential flow field. Using the wind turbine as a sensor and the FAST wind turbine dynamics code with limited degrees of freedom, we determined the aerodynamic loads imparted to the wind turbine by the vortex structure. We varied the size, strength, rotational direction, plane of rotation, and location of the vortex over a wide range of operating parameters. We identified the vortex conformation with the most significant effect on the blade root bending moment cyclic amplitude. Vortices with radii on the scale of the rotor diameter or smaller caused blade root bending moment cyclic amplitudes that contribute to high damage density. The rotational orientation, clockwise or counter-clockwise, produces little difference in the bending moment response. Vortices in the XZ plane produce bending moment amplitudes significantly greater than vortices in the YZ plane. Published in 2005 by John Wiley & Sons, Ltd.Received: 9 April 2004; Revised: 14 March 2005; Accepted: 19

  14. Evaluation of thermoluminescent kinetics parameters of inorganic dust from the camomile

    NASA Astrophysics Data System (ADS)

    Furetta, C.; Favalli, A.; Zaragoza, E. Cruz; Gomez-Ros, J. M.; Kitis, G.

    The polymineral dust extracted from the camomile herb was exposed to gamma radiation. The glow curves from these polyminerals show a large, single thermoluminiscence (TL) peak, centred at about 440 K. Because the large structure of the glow curves, it seems that the TL signal could be produced by a trap distribution instead of a single level of traps. The kinetic parameters of the glow curves have been accurately analysed using the computerized glow curve deconvolution (CGCD) method applied at different steps during a fading experiment at room temperature (RT). Deconvolution has been performed using a continuous distribution of trapping levels, uniformly distributed, including one additional peak in the high temperature region. This peak has been modelled with second-order kinetics of trap motion.

  15. Examination of parameter variations in the U. S. Navy Global Ensemble

    NASA Astrophysics Data System (ADS)

    Reynolds, Carolyn A.; Ridout, James A.; McLay, Justin G.

    2011-10-01

    The impact of parameter variations on the Navy Operational Global Atmospheric Prediction System ensemble performance is examined, and subsets of ensemble members are used to identify the relative impact of the individual parameters. Two sets of parameter variations are considered. The first set has variations in the parametrization of cumulus convection only. The second set has variations in both convection and boundary layer parametrizations. In the tropics, parameter variations significantly increase ensemble spread in wind and temperature fields, and significantly reduce Brier scores for low-level wind speed and temperature, primarily through improvements to the resolution (the impact in the extratropics is negligible). There are also small but significant improvements in the ensemble mean tropical cyclone track forecasts. For the metrics considered here, the second set of parameter variations outperforms the first set. Examination of the spread within ensemble subsets suggests that the parameter with the biggest overall impact is one that helps to control the convective updraft parcel temperature deficit at cloud base level. Variations in the von Kármán constant significantly increase ensemble spread in the low-level tropical winds near the date line, and in the low-level temperature field throughout the tropics and subtropics.

  16. Identification of the crystallization kinetic parameters of a semi-crystalline polymer by using PVTα measurement

    NASA Astrophysics Data System (ADS)

    Tardif, X.; Sobotka, V.; Boyard, N.; Delaunay, D.

    2011-05-01

    Injection molding is the most widely used process in the plastic industry. In the case of semi-crystalline polymer, crystallization kinetics impacts directly the quality of the piece, both on dimensional and mechanical aspects. The characterization of these kinetics is therefore of primary importance to model the process, in particular during the cooling phase. To be representative, this characterization must be carried out under conditions as close as possible to those encountered in the process: high pressure, high cooling rate, shearing, and potential presence of fibers. However, conventional apparatus such as the differential scanning calorimeter do not allow to reach these conditions. A PVTα apparatus, initially developed in the laboratory for the characterization of thermoset composites, was adapted to identify the crystallization kinetics. The aim of the presented study is to demonstrate the feasibility of the identification. This device allows the molding of a circular sample of 40 mm diameter and 6 mm thick by controlling the applied pressure on the sample and the temperature field on its surfaces. This mold is designed such as heat transfer is 1D within the thickness of the sample. It is equipped with two heat flux sensors to determine the average crystallization rate through the thickness and a displacement sensor for the determination of the volume change. The heat transfer problem between the polymer and the molding cavity is modeled by using a 1D conduction problem with a moving boundary, in which the control volume is a uniform temperature disk with a variable volume, and coupled to a crystallization kinetic model. An inverse method is used to identify the parameters of the crystallization kinetic model by minimizing an objective function based on the difference between the evolutions of the experimental and computed volume of the sample. The first validation of this methodology was to compare the kinetic parameters identified with this apparatus

  17. Effects of Spatial Variations in Packing Fraction on Reactor Physics Parameters in Pebble-Bed Reactors

    SciTech Connect

    William K. Terry; A. M. Ougouag; Farzad Rahnema; Michael Scott McKinley

    2003-04-01

    The well-known spatial variation of packing fraction near the outer boundary of a pebble-bed reactor core is cited. The ramifications of this variation are explored with the MCNP computer code. It is found that the variation has negligible effects on the global reactor physics parameters extracted from the MCNP calculations for use in analysis by diffusion-theory codes, but for local reaction rates the effects of the variation are naturally important. Included is some preliminary work in using first-order perturbation theory for estimating the effect of the spatial variation of packing fraction on the core eigenvalue and the fision density distribution.

  18. Kinetic Parameter Extraction of Square Wave Voltammograms from DNA-Modified Gold Electrodes

    NASA Astrophysics Data System (ADS)

    McWilliams, Marc; Wohlgamuth, Chris; Slinker, Jason

    2012-10-01

    The field of surface bound electrochemistry is important in a variety of applications specifically sensing. A fundamental understanding of the processes involved could help to improve detection limits, optimize rates of detection and direct changes in device design. Accurate extraction of electrochemical kinetic parameters such as the rate constant k and charge transfer coefficient α from cyclic voltammograms can be challenging when confronted with large background currents and relatively weak signals. The commonly used technique of Laviron analysis is both time consuming and somewhat subjective. Square wave voltammetry (SWV) is therefore an ideal alternative method given that it maximizes signal while minimizing capacitive effects. In this experiment kinetic parameters of DNA-modified gold electrodes are obtained from SWV curves through background subtraction followed by nonlinear least squares fitting using a first order quasi-reversible surface process model. The fitting is accomplished using the Nelder-Mead simplex algorithm with standard parameters and a convergence condition of less than 0.0001%. General agreement with experimental data is shown with varying levels of confidence. Difficulties specific to this experiment are discussed as well as the possible benefits of utilizing the Bayesian statistical approach of nested sampling when confronted with multiple peaks of interest and the background source is well defined.

  19. A BAYESIAN METHOD OF ESTIMATING KINETIC PARAMETERS FOR THE INACTIVATION OF CRYPTOSPORIDIUM PARVUM OOCYSTS WITH CHLORINE DIOXIDE AND OZONE

    EPA Science Inventory

    The main objective of this paper is to use Bayesian methods to estimate the kinetic parameters for the inactivation kinetics of Cryptosporidium parvum oocysts with chlorine dioxide or ozone which are characterized by the delayed Chick-Watson model, i.e., a lag phase or shoulder f...

  20. Efficient estimation of dynamic cardiac SPECT kinetic parameters using singular value decomposition reconstruction

    SciTech Connect

    Gulberg, G.T.; Huesman, R.H.; Zeng, G.L. |

    1994-05-01

    Error estimates of time activity curves are necessary to obtain efficient estimates of dynamic of dynamic cardiac SPECT kinetic parameters which are determined using weighted least squares fitting that incorporates these error estimates. In cardiac SPECT, iterative algorithms are used to obtain attenuation corrected reconstructions, and the use of an iterative algorithm makes it difficult to estimate the errors of the estimated reconstruction. An alternate approach is to estimate the reconstruction by solving the system of normal equations using singular value decomposition. This method was applied to dynamic data acquired from a canine study. A canine was injected with 25 mCi of Tc-99m-teboroxime and was imaged using a three-detector SPECT system (Picker PRISM 3000). Sequential 5 sec tomographic acquisitions were acquired for 15 min, allowing both the wash-in and wash-out of teboroxime to be measured. The projection data were reconstructed into 64x64 transaxial slices for each 5 sec acquisition using singular value decomposition to calculate the reconstructed estimate, the variance of the estimate, and the covariance between tissue and blood regions-of-interest. One 4096x4096 singular value decomposition was obtained in 71 hours using a 40 mHz Supper SPARC processor. Tissue and blood time-activity curves were generated from the attenuation corrected transaxial reconstructions. The blood activity curve was generated from a region drawn inside the left ventricle. A two-compartment model was fit to the blood and tissue activity curves to give weighted least squares estimates of blood volume fraction and wash-in and wash-out rate constants specifying teboroxime kinetics for regions of the left ventricular myocardium. As expected the weighted least squares estimates of the kinetic parameters had smaller variances than the unweighted estimates, thus demonstrating more efficient parameter estimation.

  1. Plyometric Long Jump Training With Progressive Loading Improves Kinetic and Kinematic Swimming Start Parameters.

    PubMed

    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. PMID:24531431

  2. Study of inertia welding: the sensitivity of weld configuration and strength to variations in welding parameters

    SciTech Connect

    Mote, M.W.

    1981-12-01

    An experiment is described which is designed to demonstrate the forgiveness of inertia welding, that is, the relative insensitivity of weld strength to variations in energy (rotational speed of parts) and axial force. Although easily observed variations in the welding parameters produced easily observed changes in weldment configuration and changes in dimension (upset), only extremes in parameters produced changes in weld strength. Consequently, process monitoring and product inspection would be sufficient for quality assurance in a production environment.

  3. A robust method for the joint estimation of yield coefficients and kinetic parameters in bioprocess models.

    PubMed

    Vastemans, V; Rooman, M; Bogaerts, Ph

    2009-01-01

    Bioprocess model structures that require nonlinear parameter estimation, thus initialization values, are often subject to poor identification performances because of the uncertainty on those initialization values. Under some conditions on the model structure, it is possible to partially circumvent this problem by an appropriate decoupling of the linear part of the model from the nonlinear part of it. This article provides a procedure to be followed when these structural conditions are not satisfied. An original method for decoupling two sets of parameters, namely, kinetic parameters from maximum growth, production, decay rates, and yield coefficients, is presented. It exhibits the advantage of requiring only initialization of the first subset of parameters. In comparison with a classical nonlinear estimation procedure, in which all the parameters are freed, results show enhanced robustness of model identification with regard to parameter initialization errors. This is illustrated by means of three simulation case studies: a fed-batch Human Embryo Kidney cell cultivation process using a macroscopic reaction scheme description, a process of cyclodextrin-glucanotransferase production by Bacillus circulans, and a process of simultaneous starch saccharification and glucose fermentation to lactic acid by Lactobacillus delbrückii, both based on a Luedeking-Piret model structure. Additionally, perspectives of the presented procedure in the context of systematic bioprocess modeling are promising. PMID:19455623

  4. Calculating kinetics parameters and reactivity changes with continuous-energy Monte Carlo

    SciTech Connect

    Kiedrowski, Brian C; Brown, Forrest B; Wilson, Paul

    2009-01-01

    The iterated fission probability interpretation of the adjoint flux forms the basis for a method to perform adjoint weighting of tally scores in continuous-energy Monte Carlo k-eigenvalue calculations. Applying this approach, adjoint-weighted tallies are developed for two applications: calculating point reactor kinetics parameters and estimating changes in reactivity from perturbations. Calculations are performed in the widely-used production code, MCNP, and the results of both applications are compared with discrete ordinates calculations, experimental measurements, and other Monte Carlo calculations.

  5. Effects of metformin on cell kinetic parameters of MCF-7 breast cancer cells in vitro.

    PubMed

    Topcul, Mehmet; Cetin, Idil

    2015-01-01

    In this study, the antiproliferative effects of the metformin was evaluated on MCF-7 Cells (human breast adenocarcinoma cell line). For this purpose cell kinetic parameters including cell proliferation assay, mitotic index and labelling index analysis were used. 30 μM, 65 μM and 130 μM Metformin doses were applied to cells for 24, 48 and 72 hours. The results showed that there was a significant decrease in cell proliferation, mitotic index and labelling index for all experimental groups (p<0.05) for all applications. PMID:25824763

  6. A Computer Program for the Calculation of Reactivity and Kinetic Parameters by Two-Dimensional Neutron Transport Perturbation Theory.

    Energy Science and Technology Software Center (ESTSC)

    1985-02-01

    Version 00 TP2 is a transport theory code, developed to determine reactivity effects and kinetic parameters such as effective delayed neutron fractions and mean generation time by applying the usual perturbation formalism for two-dimensional geometry.

  7. A Computer Code System for the Calculation of Reactivity and Kinetic Parameters by One-Dimensional Neutron Transport Perturbation Theory.

    Energy Science and Technology Software Center (ESTSC)

    1985-02-01

    Version 00 TP1 is a transport theory code, developed to determine reactivity effects and kinetic parameters such as effective delayed neutron fractions and mean generation time by applying the usual perturbation formalism for one-dimensional geometry.

  8. Large variation in the Rubisco kinetics of diatoms reveals diversity among their carbon-concentrating mechanisms.

    PubMed

    Young, Jodi N; Heureux, Ana M C; Sharwood, Robert E; Rickaby, Rosalind E M; Morel, François M M; Whitney, Spencer M

    2016-05-01

    While marine phytoplankton rival plants in their contribution to global primary productivity, our understanding of their photosynthesis remains rudimentary. In particular, the kinetic diversity of the CO2-fixing enzyme, Rubisco, in phytoplankton remains unknown. Here we quantify the maximum rates of carboxylation (k cat (c)), oxygenation (k cat (o)), Michaelis constants (K m) for CO2 (K C) and O2 (K O), and specificity for CO2 over O2 (SC/O) for Form I Rubisco from 11 diatom species. Diatom Rubisco shows greater variation in K C (23-68 µM), SC/O (57-116mol mol(-1)), and K O (413-2032 µM) relative to plant and algal Rubisco. The broad range of K C values mostly exceed those of C4 plant Rubisco, suggesting that the strength of the carbon-concentrating mechanism (CCM) in diatoms is more diverse, and more effective than previously predicted. The measured k cat (c) for each diatom Rubisco showed less variation (2.1-3.7s(-1)), thus averting the canonical trade-off typically observed between K C and k cat (c) for plant Form I Rubisco. Uniquely, a negative relationship between K C and cellular Rubisco content was found, suggesting variation among diatom species in how they allocate their limited cellular resources between Rubisco synthesis and their CCM. The activation status of Rubisco in each diatom was low, indicating a requirement for Rubisco activase. This work highlights the need to better understand the correlative natural diversity between the Rubisco kinetics and CCM of diatoms and the underpinning mechanistic differences in catalytic chemistry among the Form I Rubisco superfamily. PMID:27129950

  9. Large variation in the Rubisco kinetics of diatoms reveals diversity among their carbon-concentrating mechanisms

    PubMed Central

    Young, Jodi N.; Heureux, Ana M.C.; Sharwood, Robert E.; Rickaby, Rosalind E.M.; Morel, François M.M.; Whitney, Spencer M.

    2016-01-01

    While marine phytoplankton rival plants in their contribution to global primary productivity, our understanding of their photosynthesis remains rudimentary. In particular, the kinetic diversity of the CO2-fixing enzyme, Rubisco, in phytoplankton remains unknown. Here we quantify the maximum rates of carboxylation (k cat c), oxygenation (k cat o), Michaelis constants (K m) for CO2 (K C) and O2 (K O), and specificity for CO2 over O2 (SC/O) for Form I Rubisco from 11 diatom species. Diatom Rubisco shows greater variation in K C (23–68 µM), SC/O (57–116mol mol−1), and K O (413–2032 µM) relative to plant and algal Rubisco. The broad range of K C values mostly exceed those of C4 plant Rubisco, suggesting that the strength of the carbon-concentrating mechanism (CCM) in diatoms is more diverse, and more effective than previously predicted. The measured k cat c for each diatom Rubisco showed less variation (2.1–3.7s−1), thus averting the canonical trade-off typically observed between K C and k cat c for plant Form I Rubisco. Uniquely, a negative relationship between K C and cellular Rubisco content was found, suggesting variation among diatom species in how they allocate their limited cellular resources between Rubisco synthesis and their CCM. The activation status of Rubisco in each diatom was low, indicating a requirement for Rubisco activase. This work highlights the need to better understand the correlative natural diversity between the Rubisco kinetics and CCM of diatoms and the underpinning mechanistic differences in catalytic chemistry among the Form I Rubisco superfamily. PMID:27129950

  10. Determination of the kinetic parameters of BeO using isothermal decay method.

    PubMed

    Azorin Nieto, Juan; Vega, Claudia Azorin; Montalvo, Teodoro Rivera; Cabrera, Eugenio Torijano

    2016-02-01

    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 (ILD) method. The trapping parameters associated with the prominent glow peak of BeO (280°C) are reported using ILD 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. ILD method was used for determining the trapping parameters of BeO. Results obtained applying this method are in good agreement with those obtained using other methods, except in the value of the frequency factor. PMID:26656428

  11. Accounting for the kinetics in order parameter analysis: Lessons from theoretical models and a disordered peptide

    NASA Astrophysics Data System (ADS)

    Berezovska, Ganna; Prada-Gracia, Diego; Mostarda, Stefano; Rao, Francesco

    2012-11-01

    Molecular simulations as well as single molecule experiments have been widely analyzed in terms of order parameters, the latter representing candidate probes for the relevant degrees of freedom. Notwithstanding this approach is very intuitive, mounting evidence showed that such descriptions are inaccurate, leading to ambiguous definitions of states and wrong kinetics. To overcome these limitations a framework making use of order parameter fluctuations in conjunction with complex network analysis is investigated. Derived from recent advances in the analysis of single molecule time traces, this approach takes into account the fluctuations around each time point to distinguish between states that have similar values of the order parameter but different dynamics. Snapshots with similar fluctuations are used as nodes of a transition network, the clusterization of which into states provides accurate Markov-state-models of the system under study. Application of the methodology to theoretical models with a noisy order parameter as well as the dynamics of a disordered peptide illustrates the possibility to build accurate descriptions of molecular processes on the sole basis of order parameter time series without using any supplementary information.

  12. Parameters and kinetics of olive mill wastewater dephenolization by immobilized Rhodotorula glutinis cells.

    PubMed

    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. PMID:25244135

  13. Kinetic parameters of the conversion of methane precursors to methane in a hypereutrophic lake sediment.

    PubMed

    Strayer, R F; Tiedje, J M

    1978-08-01

    The kinetic parameters K(m), V(max), T(t) (turnover time), and v (natural velocity) were determined for H(2) and acetate conversion to methane by Wintergreen Lake sediment, using short-term (a few hours) methods and incubation temperatures of 10 to 14 degrees C. Estimates of the Michaelis-Menten constant, K(m), for both the consumption of hydrogen and the conversion of hydrogen to methane by sediment microflora averaged about 0.024 mumol g of dry sediment. The maximal velocity, V(max), averaged 4.8 mumol of H(2) g h for hydrogen consumption and 0.64 mumol of CH(4) g h for the conversion of hydrogen to methane during the winter. Estimated natural rates of hydrogen consumption and hydrogen conversion to methane could be calculated from the Michaelis-Menten equation and estimates of K(m), V(max), and the in situ dissolved-hydrogen concentration. These results indicate that methane may not be the only fate of hydrogen in the sediment. Among several potential hydrogen donors tested, only formate stimulated the rate of sediment methanogenesis. Formate conversion to methane was so rapid that an accurate estimate of kinetic parameters was not possible. Kinetic experiments using [2-C]acetate and sediments collected in the summer indicated that acetate was being converted to methane at or near the maximal rate. A minimum natural rate of acetate conversion to methane was estimated to be about 110 nmol of CH(4) g h, which was 66% of the V(max) (163 nmol of CH(4) g h). A 15-min preincubation of sediment with 5.0 x 10 atm of hydrogen had a pronounced effect on the kinetic parameters for the conversion of acetate to methane. The acetate pool size, expressed as the term K(m) + S(n) (S(n) is in situ substrate concentration), decreased by 37% and T(t) decreased by 43%. The V(max) remained relatively constant. A preincubation with hydrogen also caused a 37% decrease in the amount of labeled carbon dioxide produced from the metabolism of [U-C]valine by sediment heterotrophs. PMID

  14. Local field potentials in primate motor cortex encode grasp kinetic parameters

    PubMed Central

    Milekovic, Tomislav; Truccolo, Wilson; Grün, Sonja; Riehle, Alexa; Brochier, Thomas

    2015-01-01

    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. PMID:25869861

  15. Local field potentials in primate motor cortex encode grasp kinetic parameters.

    PubMed

    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. PMID:25869861

  16. Optimization of glycerol fed-batch fermentation in different reactor states: a variable kinetic parameter approach.

    PubMed

    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. PMID:12049203

  17. Variation ranges of motion parameters for space debris in the geosynchronous ring

    NASA Astrophysics Data System (ADS)

    Zhao, Chang-Yin; Zhang, Ming-Jiang; Yu, Sheng-Xian; Xiong, Jian-Ning; Zhang, Wei; Zhu, Ting-Lei

    2016-06-01

    We propose a method that uses only one set of known orbital elements to directly determine the motion state and variation ranges of motion parameters, including the inclination, right ascension of the ascending node (RAAN), evolution period of the orbital plane, maximum libration amplitude of the semi-major axis, commensurable angle, libration period and drift period, for space debris in the geosynchronous ring. These variation ranges of motion parameters characterize the evolution of debris quantitatively and illustrate the three-dimensional (3D) variations. Employing the proposed method, we study the motion state and variation ranges of motion parameters for catalogued and uncontrolled space debris with existing two-line element (TLE) data in the geosynchronous ring, and present specific results. We also compare our results with actual observational results derived from long-term TLE historical data, and find that, in the vast majority of cases, our proposed method of determining the motion state and variation ranges of motion parameters via only one set of known orbital elements is effective. In addition, before the elaboration of the variation ranges of motion parameters stated above, we obtain the statistical distribution of space debris in the orbital plane and the daily motion from the TLE historical data. We then derive two mathematical formulae that explain the statistical distribution and daily motion on the basis of the essence of dynamics, which contributes to the characterization of the evolution of debris.

  18. Mathematical model for studying the variation of the electrical parameters in functioning of nonlinear loads

    NASA Astrophysics Data System (ADS)

    Rob, Raluca; Rat, Cezara

    2013-10-01

    This paper presents a study concerning the variation of the most important electrical parameters, measured during the functioning of an electrothermal installation with electromagnetic induction. Two measuring methods are described: the first method consists in using a power and energy quality analyzer and the second uses a data acquisition system that contains an adapting interface and a data acquisition board connected to a computer. In order to compute the electrical parameters, a LabVIEW application was designed. The data acquisition system is able to measure in real time the variation of the parameters and also to save the obtained information.

  19. Variational Formulation of Particle Algorithms for Kinetic E&M Plasma Simulations

    NASA Astrophysics Data System (ADS)

    Stamm, Alexander; Shadwick, Bradley; Evstatiev, Evstati

    2013-10-01

    A rigorous variational method was used to derive a self-consistent set of equations of motion from a discretized Lagrangian to study kinetic plasmas. Discretization of the Lagrangian was performed by reduction of the phase-space distribution function to a collection of finite-sized macro-particles of arbitrary shape and discretization of field quantities onto a spatial grid. The equations of motion were then obtained by demanding the action be stationary. This approach may be used in both lab frame and moving window coordinates, which improve computational efficiency when modeling laser-plasma interactions. The primary advantage of the variational approach is preservation of Lagrangian symmetries, which in our case leads to energy conservation and avoids difficulties with grid heating. Additionally, this approach decouples particle size from grid spacing and relaxes restrictions on particle shape, leading to a decrease in numerical noise. The variational approach also guarantees consistent ordering and is amiable to higher order methods in both space and time. Simulations conducted with the new equations of motion demonstrate the desired energy conservation and a decrease in numerical noise. This work was supported by the U.S. Department of Education grant P200A090156 and by the U.S. Department of Energy under Contract No. DE-FG02-08ER55000.

  20. Chemical kinetics parameters and model validation for the gasification of PCEA nuclear graphite

    SciTech Connect

    El-Genk, Mohamed S; Tournier, Jean-Michel; Contescu, Cristian I

    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%.

  1. The role of test parameters on the kinetics and thermodynamics of glass leaching. [None

    SciTech Connect

    Jantzen, C M

    1988-01-01

    The relative durabilities of nuclear waste, natural, and ancient glasses have been assessed by standard laboratory leach tests. Different test conditions result in different glass surface areas (SA), leachant volumes (V), and test durations (t). Leachate concentrations are known to be a parabolic function of the kinetic test parameter SAV/center dot/t. Based on durability experiments of glass monoliths at low (SAV)/center dot/ glass durability has been shown to be a logarithmic function of the thermodynamic hydration free energy, ..delta..G/sub hyd/. The thermodynamic hydration free energy, ..delta..G/sub hyd/, can be calculated from glass composition and solution pH. In the repository environment high effective glass surface areas to solution volume ratios may occur as a result of slow groundwater flow rates. The application of hydration thermodynamics to crushed glass, high (SAV)/center dot/t, durability tests has been demonstrated. The relative contributions of the kinetic test parameters, (SAV)/center dot/t, and the thermodynamic parameter, ..delta..G/sub hyd/, have been shown to define a plane in ..delta..G/sub hyd/-concentration-(SAV)/center dot/t space. At constant test conditions, e.g. constant (SAV/center dot/t, the intersection with this surface indicates that all /delta G//sub hyd/-concentration plots should have similar slopes and predict the same relative durabilities for various glasses as a function of glass composition. Using this approach, the durability of nuclear waste glasses has been interpolated to be -- 10/sup 6/ years and no less than 10/sup 3/ years. 28 refs., 24 figs.

  2. {sup 82}Rb kinetic parameter variability due to depth of anesthesia in the anesthetized canine

    SciTech Connect

    Coxson, P.G.; Brennan, K.M.; Yang, L.

    1995-05-01

    The effect of {open_quotes}depth of anesthesia{close_quotes} on {sup 82}Rb kinetic parameter estimates in the myocardium was tested in a series of replicated studies on six dogs using the Donner 600-Crystal Positron Tomograph. A single lateral slice through the myocardium was imaged following each of four successive injections of {sup 82}Rb. For three of the injections the animals were lightly anesthetized (mean blood pressure about 90 mmHg). For the second injection, the amount of anesthetic was increased until blood pressure dipped to about 70 mHg. The fourth injection was preceded by an infusion of dipyridamole to induce a stress-state. The entire sequence was repeated at least twice with each of the six animals. A two compartment model with parameters k{sub 1} (uptake rate), k{sub 2} (wash-out rate), and f{sub v} (vascular fraction) was fit to the data. There was a consistent finding of a 20% to 30% decrease in k{sub 1} during the deeply anesthetized state compared with the two lightly anesthetized rest states. Analysis of variance showed that the difference observed is significant, though small in comparison with the difference between the rest and stress states (60% to 160% increase). The difference between the two lightly anesthetized states was not significant. Kinetic PET studies using dogs are routinely carried out with the animal anesthetized. Depth of anesthesia has been suspected as as source of variability in parameter estimates, but this conjecture has not previously been systematically investigated. These studies at extremes in the depth of anesthesia show a small but predictable effect on the uptake k{sub 1} of {sup 82}Rb.

  3. Kinetic modeling of molecular motors: pause model and parameter determination from single-molecule experiments

    NASA Astrophysics Data System (ADS)

    Morin, José A.; Ibarra, Borja; Cao, Francisco J.

    2016-05-01

    Single-molecule manipulation experiments of molecular motors provide essential information about the rate and conformational changes of the steps of the reaction located along the manipulation coordinate. This information is not always sufficient to define a particular kinetic cycle. Recent single-molecule experiments with optical tweezers showed that the DNA unwinding activity of a Phi29 DNA polymerase mutant presents a complex pause behavior, which includes short and long pauses. Here we show that different kinetic models, considering different connections between the active and the pause states, can explain the experimental pause behavior. Both the two independent pause model and the two connected pause model are able to describe the pause behavior of a mutated Phi29 DNA polymerase observed in an optical tweezers single-molecule experiment. For the two independent pause model all parameters are fixed by the observed data, while for the more general two connected pause model there is a range of values of the parameters compatible with the observed data (which can be expressed in terms of two of the rates and their force dependencies). This general model includes models with indirect entry and exit to the long-pause state, and also models with cycling in both directions. Additionally, assuming that detailed balance is verified, which forbids cycling, this reduces the ranges of the values of the parameters (which can then be expressed in terms of one rate and its force dependency). The resulting model interpolates between the independent pause model and the indirect entry and exit to the long-pause state model

  4. Evaluation of the interindividual human variation in bioactivation of methyleugenol using physiologically based kinetic modeling and Monte Carlo simulations.

    PubMed

    Al-Subeihi, Ala A A; Alhusainy, Wasma; Kiwamoto, Reiko; Spenkelink, Bert; van Bladeren, Peter J; Rietjens, Ivonne M C M; Punt, Ans

    2015-03-01

    The present study aims at predicting the level of formation of the ultimate carcinogenic metabolite of methyleugenol, 1'-sulfooxymethyleugenol, in the human population by taking variability in key bioactivation and detoxification reactions into account using Monte Carlo simulations. Depending on the metabolic route, variation was simulated based on kinetic constants obtained from incubations with a range of individual human liver fractions or by combining kinetic constants obtained for specific isoenzymes with literature reported human variation in the activity of these enzymes. The results of the study indicate that formation of 1'-sulfooxymethyleugenol is predominantly affected by variation in i) P450 1A2-catalyzed bioactivation of methyleugenol to 1'-hydroxymethyleugenol, ii) P450 2B6-catalyzed epoxidation of methyleugenol, iii) the apparent kinetic constants for oxidation of 1'-hydroxymethyleugenol, and iv) the apparent kinetic constants for sulfation of 1'-hydroxymethyleugenol. Based on the Monte Carlo simulations a so-called chemical-specific adjustment factor (CSAF) for intraspecies variation could be derived by dividing different percentiles by the 50th percentile of the predicted population distribution for 1'-sulfooxymethyleugenol formation. The obtained CSAF value at the 90th percentile was 3.2, indicating that the default uncertainty factor of 3.16 for human variability in kinetics may adequately cover the variation within 90% of the population. Covering 99% of the population requires a larger uncertainty factor of 6.4. In conclusion, the results showed that adequate predictions on interindividual human variation can be made with Monte Carlo-based PBK modeling. For methyleugenol this variation was observed to be in line with the default variation generally assumed in risk assessment. PMID:25549870

  5. An identification algorithm of model kinetic parameters of the interfacial layer growth in fiber composites

    NASA Astrophysics Data System (ADS)

    Zubov, V.; Lurie, S.; Solyaev, Y.

    2016-04-01

    This paper considers the identification algorithm of parameters included in a parabolic law that is often used to predict the time dependence of the thickness of the interfacial layers in the structure of composite materials based on a metal matrix. The incubation period of the process and the speed of reaction and pressure are taken into account. The proposed algorithm of identification is based on the introduction of a minimized objective function of a special kind. The problem of identification of unknown parameters in the parabolic law is formulated in a variational form. The authors of the paper have determined the desired parameters, under which the objective function has a minimum value. It is shown that on the basis of four known experimental values of the interfacial layer thickness, corresponding to different values of temperature, pressure and the time of the interfacial layer growth, it is possible to identified four model parameters. They are the activation energy, a pre-exponential parameter, the delay time of the start of the interfacial layer formation, and the parameter determining the pressure effect on the rate of interfacial layer growth. The stability of the proposed identification algorithm is also studied.

  6. Seasonal, diurnal and vertical variation in photosynthetic parameters in Phyllostachys humilis bamboo plants.

    PubMed

    Van Goethem, Davina; Potters, Geert; De Smedt, Sebastiaan; Gu, Lianhong; Samson, Roeland

    2014-06-01

    In recent years, temperate bamboo species have been introduced in Europe for multiple uses such as renewable bio-based materials (wood, composites, fibres, biochemicals…) and numerous ecological functions (soil and water conservation, erosion control, phytoremediation…). Despite their interesting potential, little is known on the ecophysiology of these plants in their new habitat. Therefore, we studied gas exchange parameters on a full soil bamboo plantation of Phyllostachys humilis on a test field in Ireland (Europe). We evaluated the seasonal, diurnal and vertical variation of the parameters of two commonly used photosynthetic models, i.e. the light response curve (LRC) model and the model of Farquhar, von Caemmerer and Berry (FvCB). Furthermore, we tested if there were environmental effects on the photosynthetic parameters of these models and if a correlation between photosynthetic parameters and fluorescence parameters was present, fluorescence parameters can be easily and fast determined. Our results show that the gas exchange parameters do not vary diurnally or vertically. Only seasonal variations were found and should, therefore, be taken into account when using the LRC or FvCB model when modelling canopy growth. Therefore, a big-leaf model or a sunlit-shade model can be used for modelling bamboo growth in Western Europe. There is no straightforward relation between environmental variables and the photosynthetic parameters. Although fluorescence parameters showed a correlation with the photosynthetic parameters, application of such correlation may be limited. PMID:24585025

  7. A new multi-wavelength model-based method for determination of enzyme kinetic parameters.

    PubMed

    Sorouraddin, Mohammad-Hossein; Amini, Kaveh; Naseri, Abdolhossein; Vallipour, Javad; Hanaee, Jalal; Rashidi, Mohammad-Reza

    2010-09-01

    Lineweaver-Burk plot analysis is the most widely used method to determine enzyme kinetic parameters. In the spectrophotometric determination of enzyme activity using the Lineweaver-Burk plot, it is necessary to find a wavelength at which only the substrate or the product has absorbance without any spectroscopic interference of the other reaction components. Moreover, in this method, different initial concentrations of the substrate should be used to obtain the initial velocities required for Lineweaver-Burk plot analysis. In the present work, a multi-wavelength model-based method has been developed and validated to determine Michaelis-Menten constants for some enzyme reactions. In this method, a selective wavelength region and several experiments with different initial concentrations of the substrate are not required. The absorbance data of the kinetic assays are fitted by non-linear regression coupled to the numeric integration of the related differential equation. To indicate the applicability of the proposed method, the Michaelis-Menten constants for the oxidation of phenanthridine, 6-deoxypenciclovir and xanthine by molybdenum hydroxylases were determined using only a single initial concentration of the substrate, regardless of any spectral overlap. PMID:20826949

  8. Kinetic study of the anaerobic biodegradation of alkyl polyglucosides and the influence of their structural parameters.

    PubMed

    Ríos, Francisco; Fernández-Arteaga, Alejandro; Lechuga, Manuela; Jurado, Encarnación; Fernández-Serrano, Mercedes

    2016-05-01

    This paper reports a study of the anaerobic biodegradation of non-ionic surfactants alkyl polyglucosides applying the method by measurement of the biogas production in digested sludge. Three alkyl polyglucosides with different length alkyl chain and degree of polymerization of the glucose units were tested. The influence of their structural parameters was evaluated, and the characteristics parameters of the anaerobic biodegradation were determined. Results show that alkyl polyglucosides, at the standard initial concentration of 100 mgC L(-1), are not completely biodegradable in anaerobic conditions because they inhibit the biogas production. The alkyl polyglucoside having the shortest alkyl chain showed the fastest biodegradability and reached the higher percentage of final mineralization. The anaerobic process was well adjusted to a pseudo first-order equation using the carbon produced as gas during the test; also, kinetics parameters and a global rate constant for all the involved metabolic process were determined. This modeling is helpful to evaluate the biodegradation or the persistence of alkyl polyglucosides under anaerobic conditions in the environment and in the wastewater treatment. PMID:26820643

  9. Kinetics of surface segregation in metallic alloys with first-principles interaction parameters

    SciTech Connect

    Wille, L.T. |; Ouannasser, S.; Dreysse, H.

    1996-12-31

    The authors report the results of Monte Carlo simulations of the kinetics of surface segregation at the (001) face of CuNi and MoW alloys. These two systems were selected because they are based on different lattice structures and show contrasting segregation behavior: CuNi exhibits a monotonic profile, while that of MoW is oscillatory. To describe the energetics they have determined a set of effective cluster interactions (ECI) which govern the ordering or clustering tendencies of these alloys. The ECI were obtained by means of tight-binding electronic structure calculations in which no adjustable or experimentally determined parameters were used. Equilibrium segregation profiles are calculated and a series of quenches are performed. The layer concentrations are studied as a function of time and the existence of metastable phases in the surface region is investigated.

  10. Characterization of DuPont photopolymer: determination of kinetic parameters in a diffusion model

    NASA Astrophysics Data System (ADS)

    Moreau, Vincent; Renotte, Yvon; Lion, Yves

    2002-06-01

    We investigate the recording dynamics of Omnidex photopolymer film from DuPont. We use a reviewed version of the diffusion model proposed by Zhao and Mouroulis [J. Mod. Opt. 41, 1929 (1994)] in order to describe the recording response that combined photopolymerization and free-monomer diffusion process. Two different experiments are detailed that lead to the determination of material kinetic parameters. These values are introduced in the numerical model to provide quantitative simulations of a grating formation under various holographic exposures. Theoretical results are experimentally checked as a validation of the model. We extend its applications to several secondary investigations, such as volume-shrinkage influence on refractive-index distribution and spectral selectivity of reflection gratings. This study improves the understanding of the recording process and consequently allows to build more accurate holographic components in this material to be built.

  11. Sensitivity of natural gas HCCI combustion to fuel and operating parameters using detailed kinetic modeling

    SciTech Connect

    Aceves, S; Dibble, R; Flowers, D; Smith, J R; Westbrook, C K

    1999-07-19

    This paper uses the HCT (Hydrodynamics, Chemistry and Transport) chemical kinetics code to analyze natural gas HCCI combustion in an engine. The HCT code has been modified to better represent the conditions existing inside an engine, including a wall heat transfer correlation. Combustion control and low power output per displacement remain as two of the biggest challenges to obtaining satisfactory performance out of an HCCI engine, and these are addressed in this paper. The paper considers the effect of natural gas composition on HCCI combustion, and then explores three control strategies for HCCI engines: DME (dimethyl ether) addition, intake heating and hot EGR addition. The results show that HCCI combustion is sensitive to natural gas composition, and an active control may be required to compensate for possible changes in composition. The three control strategies being considered have a significant effect in changing the combustion parameters for the engine, and should be able to control HCCI combustion.

  12. Optimization of Process Parameters and Kinetic Model of Enzymatic Extraction of Polyphenols from Lonicerae Flos

    PubMed Central

    Kong, Fansheng; Yu, Shujuan; Bi, Yongguang; Huang, Xiaojun; Huang, Mengqian

    2016-01-01

    Objective: To optimize and verify the cellulase extraction of polyphenols from honeysuckle and provide a reference for enzymatic extracting polyphenols from honeysuckle. Materials and Methods: The uniform design was used According to Fick's first law and kinetic model, fitting analysis of the dynamic process of enzymatic extracting polyphenols was conducted. Results: The optimum enzymatic extraction parameters for polyphenols from honeysuckle are found to be 80% (v/v) of alcohol, 35:1 (mL/g) of liquid-solid ratio, 80°C of extraction temperature, 8.5 of pH, 6.0 mg of enzyme levels, and 130 min of extraction time. Under the optimal conditions, the extraction rate of polyphenols was 3.03%. The kinetic experiments indicated kinetic equation had a good linear relationship with t even under the conditions of different levels of enzyme and temperature, which means fitting curve tallies well with the experimental values. Conclusion: The results of quantification showed that the results provide a reference for enzymatic extracting polyphenols from honeysuckle. SUMMARY Lonicerae flos (Lonicera japonica Thunb.) is a material of traditional Chinese medicine and healthy drinks, of which active compounds mainly is polyphenols. At present, plant polyphenols are the hotspots centents of food, cosmetic and medicine, because it has strong bioactivity. Several traditional methods are available for the extraction of plant polyphenols including impregnation, solvent extraction, ultrasonic extraction, hot-water extraction, alkaline dilute alcohol or alkaline water extraction, microwave extraction and Supercritical CO2 extraction. But now, an increasing number of research on using cellulase to extract active ingredients from plants. Enzymatic method is widely used for enzyme have excellent properties of high reaction efficiency and specificity, moderate reaction conditions, shorter extraction time and easier to control, less damage to the active ingredient. At present, the enzymatic

  13. Kinetic and temporospatial parameters in male and female cats walking over a pressure sensing walkway

    PubMed Central

    2013-01-01

    Background Several factors may influence kinetic data measurements, including body conformation and body mass. In addition, gender differences in gait pattern have been observed in healthy humans. Therefore, the aim of this study was to compare the kinetic and temporospatial parameters in clinically healthy male and female cats using a pressure-sensitive walkway. Eighteen crossbreed adult cats were divided into two groups: G1 had ten male cats (nine neutered) aged from 1 to 4 years and body mass 3.1-6.8 kg; G2 had eight spayed female cats, aged from 1 to 6 years and body mass 3.3-4.75 kg. The data from the first five valid trials were collected for each cat. A trial was considered valid if the cat maintained a velocity between 0.54-0.74 m/s and acceleration from -0.20 to 0.20 m/s2. The peak vertical force (PVF), vertical impulse (VI), gait cycle time, stance time, swing time, stride length, and percentage body weight distribution among the four limbs were determined. In addition, the lengths of each forelimb and each hind limb were measured using a tape with the animal standing. Results No significant differences were observed in each group in either the forelimbs or the hind limbs or between the left and right sides for any of the variables. For both groups, the PVF (%BW), the VI, and the percentage body weight distribution were higher at the forelimbs than the hind limbs. The stride length was larger for males; however, the other kinetic and temporospatial variables did not show any statistically significant differences between the groups. The lengths of the forelimbs and hind limbs were larger in the male cats. There was a significant moderate positive correlation between the stride length and the length of the limbs. Conclusions In conclusion, the only difference observed between male and female cats was the stride length, and this was due to the greater body size of male cats. This difference did not affect other temporospatial or kinetics variables

  14. Sensitivity of tire response to variations in material and geometric parameters

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K.; Tanner, John A.; Peters, Jeanne M.

    1992-01-01

    A computational procedure is presented for evaluating the analytic sensitivity derivatives of the tire response with respect to material and geometric parameters of the tire. The tire is modeled by using a two-dimensional laminated anisotropic shell theory with the effects of variation in material and geometric parameters included. The computational procedure is applied to the case of uniform inflation pressure on the Space Shuttle nose-gear tire when subjected to uniform inflation pressure. Numerical results are presented showing the sensitivity of the different response quantities to variations in the material characteristics of both the cord and the rubber.

  15. Simulation of the interannual variations of tropospheric ozone over China: Roles of variations in meteorological parameters and anthropogenic emissions

    NASA Astrophysics Data System (ADS)

    Lou, Sijia; Liao, Hong; Yang, Yang; Mu, Qing

    2015-12-01

    We quantify the interannual variations (IAVs) of tropospheric O3 over China for the years 2004-2012 by using the one-way nested-grid version of the global three-dimensional Goddard Earth Observing System chemical transport model (GEOS-Chem). The roles of variations in meteorological fields and anthropogenic emissions of O3 precursors are examined separately and together through sensitivity simulations. With variations in both meteorological parameters and emissions, simulated seasonal mean surface-layer O3 concentrations over North China (NC, 110-120°E, 32-42°N) exhibit the largest IAVs in June-July-August (JJA). The regionally averaged absolute percent departure from the mean (APDM) values over NC are 0.7%, 3.2%, 3.9%, and 2.1% in December-January-February (DJF), March-April-May (MAM), and September-October-November (SON), respectively. Over South China (SC, 110-120°E, 22-32°N), the IAVs of O3 are found maximum in MAM, and minimum in JJA; the APDM values are 2.7%, 3.7%, 1.4%, and 2.6% in DJF, MAM, JJA, and SON, respectively. With respect to the IAVs of O3 over the Sichuan Basin (SCB, 102-110°E, 27-33°N), the APDM values are simulated to be 2.7-3.8% throughout the year. The IAVs in surface-layer O3 by variations in meteorological fields are simulated to be larger than those by variations in anthropogenic emissions throughout the year in NC and SC except for JJA in SC. The relatively more important role of variations in anthropogenic emissions is simulated in SCB in all seasons. Process analyses are performed to identify key meteorological parameters that influence the IAVs of O3 over NC, SC, and SCB. Over all of these regions, variations in winds are found to have the largest impact on the IAVs of O3, followed by those in temperature and specific humidity. Considering that the APDM values represent the IAVs averaged over 2004-2012, the magnitudes of IAVs of O3 for specific years can be more significant than the numbers reported here. Our results have

  16. Stochastic modelling of daily rainfall in Nigeria: intra-annual variation of model parameters

    NASA Astrophysics Data System (ADS)

    Jimoh, O. D.; Webster, P.

    1999-09-01

    A Markov model of order 1 may be used to describe the occurrence of wet and dry days in Nigeria. Such models feature two parameter sets; P01 to characterise the probability of a wet day following a dry day and P11 to characterise the probability of a wet day following a wet day. The model parameter sets, when estimated from historical records, are characterised by a distinctive seasonal behaviour. However, the comparison of this seasonal behaviour between rainfall stations is hampered by the noise reflecting the high variability of parameters on successive days. The first part of this article is concerned with methods for smoothing these inherently noisy parameter sets. Smoothing has been approached using Fourier series, averaging techniques, or a combination thereof. It has been found that different methods generally perform well with respect to estimation of the average number of wet events and the frequency duration curves of wet and dry events. Parameterisation of the P01 parameter set is more successful than the P11 in view of the relatively small number of wet events lasting two or more days. The second part of the article is concerned with describing the regional variation in smoothed parameter sets. There is a systematic variation in the P01 parameter set as one moves northwards. In contrast, there is limited regional variation in the P11 set. Although this regional variation in P01 appears to be related to the gradual movement of the Inter Tropical Convergence Zone, the contrasting behaviour of the two parameter sets is difficult to explain on physical grounds.

  17. Study of kinetic parameters in a mechanistic model for bioethanol production through a screening technique and optimization.

    PubMed

    de Andrade, Rafael Ramos; Rivera, Elmer Ccopa; Atala, Daniel I P; Filho, Rubens Maciel; Filho, Francisco Maugeri; Costa, Aline C

    2009-08-01

    The accurate description of the kinetics and robust modeling of biotechnological processes can only be achieved by incorporating reliable methodologies to easily update the model when there are changes in operational conditions. The purpose of this work is to provide a systematic approach with which to perform model parameters screening and updating in biotechnological processes. Batch experiments are performed to develop a mechanistic model, considering the effect of temperature on the kinetics, and further experiments (batch fermentations using sugar cane molasses from a different harvest) are used to validate the effectiveness of screening before parameters updating. The reduction in the number of kinetic parameters to be re-estimated enabled by the screening procedure reduces significantly the complexity of the optimization, which makes the updating procedure to be significantly quicker, while resulting in accurate performance of the updated model. PMID:19125302

  18. Evaluation of the interindividual human variation in bioactivation of methyleugenol using physiologically based kinetic modeling and Monte Carlo simulations

    SciTech Connect

    Al-Subeihi, Ala' A.A.; Alhusainy, Wasma; Kiwamoto, Reiko; Spenkelink, Bert; Bladeren, Peter J. van; Rietjens, Ivonne M.C.M.; Punt, Ans

    2015-03-01

    The present study aims at predicting the level of formation of the ultimate carcinogenic metabolite of methyleugenol, 1′-sulfooxymethyleugenol, in the human population by taking variability in key bioactivation and detoxification reactions into account using Monte Carlo simulations. Depending on the metabolic route, variation was simulated based on kinetic constants obtained from incubations with a range of individual human liver fractions or by combining kinetic constants obtained for specific isoenzymes with literature reported human variation in the activity of these enzymes. The results of the study indicate that formation of 1′-sulfooxymethyleugenol is predominantly affected by variation in i) P450 1A2-catalyzed bioactivation of methyleugenol to 1′-hydroxymethyleugenol, ii) P450 2B6-catalyzed epoxidation of methyleugenol, iii) the apparent kinetic constants for oxidation of 1′-hydroxymethyleugenol, and iv) the apparent kinetic constants for sulfation of 1′-hydroxymethyleugenol. Based on the Monte Carlo simulations a so-called chemical-specific adjustment factor (CSAF) for intraspecies variation could be derived by dividing different percentiles by the 50th percentile of the predicted population distribution for 1′-sulfooxymethyleugenol formation. The obtained CSAF value at the 90th percentile was 3.2, indicating that the default uncertainty factor of 3.16 for human variability in kinetics may adequately cover the variation within 90% of the population. Covering 99% of the population requires a larger uncertainty factor of 6.4. In conclusion, the results showed that adequate predictions on interindividual human variation can be made with Monte Carlo-based PBK modeling. For methyleugenol this variation was observed to be in line with the default variation generally assumed in risk assessment. - Highlights: • Interindividual human differences in methyleugenol bioactivation were simulated. • This was done using in vitro incubations, PBK modeling

  19. A new methodology to determine kinetic parameters for one- and two-step chemical models

    NASA Technical Reports Server (NTRS)

    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.

  20. Turbulence intensity and turbulent kinetic energy parameters over a heterogeneous terrain of Loess Plateau

    NASA Astrophysics Data System (ADS)

    Yue, Ping; Zhang, Qiang; Wang, Runyuan; Li, Yaohui; Wang, Sheng

    2015-09-01

    A deep understanding of turbulence structure is important for investigating the characteristics of the atmospheric boundary layer, especially over heterogeneous terrain. In the present study, turbulence intensity and turbulent kinetic energy (TKE) parameters are analyzed for different conditions with respect to stability, wind direction and wind speed over a valley region of the Loess Plateau of China during December 2003 and January 2004. The purpose of the study is to examine whether the observed turbulence intensity and TKE parameters satisfy Monin-Obukhov similarity theory (MOST), and analyze the wind shear effect on, and thermal buoyancy function of, the TKE, despite the terrain heterogeneity. The results demonstrate that the normalized intensity of turbulence follows MOST for all stability in the horizontal and vertical directions, as well as the normalized TKE in the horizontal direction. The shear effect of the wind speed in the Loess Plateau region is strong in winter and could enhance turbulence for all stability conditions. During daytime, the buoyancy and shear effect together constitute the generation of TKE under unstable conditions. At night, the contribution of buoyancy to TKE is relatively small, and mechanical shearing is the main production form of turbulence.

  1. Modeling kinetic rate variation in third generation DNA sequencing data to detect putative modifications to DNA bases.

    PubMed

    Schadt, Eric E; Banerjee, Onureena; Fang, Gang; Feng, Zhixing; Wong, Wing H; Zhang, Xuegong; Kislyuk, Andrey; Clark, Tyson A; Luong, Khai; Keren-Paz, Alona; Chess, Andrew; Kumar, Vipin; Chen-Plotkin, Alice; Sondheimer, Neal; Korlach, Jonas; Kasarskis, Andrew

    2013-01-01

    Current generation DNA sequencing instruments are moving closer to seamlessly sequencing genomes of entire populations as a routine part of scientific investigation. However, while significant inroads have been made identifying small nucleotide variation and structural variations in DNA that impact phenotypes of interest, progress has not been as dramatic regarding epigenetic changes and base-level damage to DNA, largely due to technological limitations in assaying all known and unknown types of modifications at genome scale. Recently, single-molecule real time (SMRT) sequencing has been reported to identify kinetic variation (KV) events that have been demonstrated to reflect epigenetic changes of every known type, providing a path forward for detecting base modifications as a routine part of sequencing. However, to date no statistical framework has been proposed to enhance the power to detect these events while also controlling for false-positive events. By modeling enzyme kinetics in the neighborhood of an arbitrary location in a genomic region of interest as a conditional random field, we provide a statistical framework for incorporating kinetic information at a test position of interest as well as at neighboring sites that help enhance the power to detect KV events. The performance of this and related models is explored, with the best-performing model applied to plasmid DNA isolated from Escherichia coli and mitochondrial DNA isolated from human brain tissue. We highlight widespread kinetic variation events, some of which strongly associate with known modification events, while others represent putative chemically modified sites of unknown types. PMID:23093720

  2. A theoretical model of phase changes of a klystron due to variation of operating parameters

    NASA Technical Reports Server (NTRS)

    Kupiszewski, A.

    1980-01-01

    A mathematical model for phase changes of the VA-876 CW klystron amplifier output is presented and variations of several operating parameters are considered. The theoretical approach to the problem is based upon a gridded gap modeling with inclusion of a second order correction term so that actual gap geometry is reflected in the formulation. Physical measurements are contrasted to theoretical calculations.

  3. Diurnal variation of oxygen and carbonate system parameters in Tampa Bay and Florida Bay

    USGS Publications Warehouse

    Yates, K.K.; Dufore, C.; Smiley, N.; Jackson, C.; Halley, R.B.

    2007-01-01

    Oxygen and carbonate system parameters were measured, in situ, over diurnal cycles in Tampa Bay and Florida Bay, Florida. All system parameters showed distinct diurnal trends in Tampa Bay with an average range of diurnal variation of 39.1 μmol kg− 1 for total alkalinity, 165.1 μmol kg− 1 for total CO2, 0.22 for pH, 0.093 mmol L− 1 for dissolved oxygen, and 218.1 μatm for pCO2. Average range of diurnal variation for system parameters in Tampa Bay was 73% to 93% of the seasonal range of variability for dissolved oxygen and pH. All system parameters measured in Florida Bay showed distinct variation over diurnal time-scales. However, clear diurnal trends were less evident. The average range of diurnal variability in Florida Bay was 62.8 μmol kg− 1 for total alkalinity, 130.4 μmol kg− 1 for total CO2, 0.13 for pH, 0.053 mmol L− 1 for dissolved oxygen, and 139.8 μatm for pCO2. The average range of diurnal variation was 14% to 102% of the seasonal ranges for these parameters. Diurnal variability in system parameters was most influenced by primary productivity and respiration of benthic communities in Tampa Bay, and by precipitation and dissolution of calcium carbonate in Florida Bay. Our data indicate that use of seasonal data sets without careful consideration of diurnal variability may impart significant error in calculations of annual carbon and oxygen budgets. These observations reinforce the need for higher temporal resolution measurements of oxygen and carbon system parameters in coastal ecosystems.

  4. Study of variation in human upper body parameters and motion for use in robotics based simulation.

    PubMed

    Lura, Derek J; Carey, Stephanie L; Dubey, Rajiv V

    2013-01-01

    This paper reviews the variations in human upper body motion of subjects completing activities of daily living. This study was completed to serve as a reference to evaluate the quality of simulated of human motion. In this paper we define the variation in motion as the variation in subjects' parameters (link lengths), joint angles, and hand positions, for a given task. All of these variations are related by forward kinematic equations. Motion data from eight healthy right hand dominant adults performing three activities of daily living (brushing hair, drinking from a cup, and opening a door) were collected using an eight camera Vicon motion analysis system. Subject parameters were calculated using relative positions of functional joint center locations between segments. Joint angles were calculated by Euler angle rotations between body segments. Hand position was defined as the origin of the hand frame relative to the pelvis frame. The variance of recorded human motion was analyzed based on the standard deviations of subject parameters, joint angles, and hand positions. Variances in joint angles were found to be similar in magnitude to root mean squared error of kinematics based motion simulation. To evaluate the relative variance, the forward kinematic solutions of the trials were found after removing subject parameter variance and reducing joint angle variance. The variance in the forward kinematic solution was then compared to the recorded hand position variance. Reductions in subject parameter and joint angle variance produced a proportionally much smaller reduction in the calculated hand position variance. Using the average instead of individual subject parameters had only a small impact on hand position variance. Modifying joint angles to reduce variance had a greater impact on the calculated hand position variance than using average subject parameters, but was still a relatively small change. Future work will focus on using these results to create formalized

  5. Reflectance of vegetation, soil, and water. [effects of measurable plant parameters on multispectral signal variations

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L. (Principal Investigator)

    1974-01-01

    The author has identified the following significant results. Reflectance of crop residues, that are important in reducing wind and water erosion, was more often different from bare soil in band 4 than in bands 5, 6, or 7. The plant parameters leaf area index, plant population, plant cover, and plant height explained 95.9 percent of the variation in band 7 (reflective infrared) digital counts for cotton and 78.2 percent of the variation in digital counts for the combined crops sorghum and corn; hence, measurable plant parameters explain most of the signal variation recorded for corpland. Leaf area index and plant population are both highly correlated with crop yields; since plant population can be readily measured (or possibly inferred from seeding rates), it is useful measurement for calibrating ERTS-type MSS digital data in terms of yield.

  6. Computer controlled automated assay for comprehensive studies of enzyme kinetic parameters.

    PubMed

    Bonowski, Felix; Kitanovic, Ana; Ruoff, Peter; Holzwarth, Jinda; Kitanovic, Igor; Bui, Van Ngoc; Lederer, Elke; Wölfl, Stefan

    2010-01-01

    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-sites at the

  7. Variational cross-validation of slow dynamical modes in molecular kinetics

    PubMed Central

    Pande, Vijay S.

    2015-01-01

    Markov state models are a widely used method for approximating the eigenspectrum of the molecular dynamics propagator, yielding insight into the long-timescale statistical kinetics and slow dynamical modes of biomolecular systems. However, the lack of a unified theoretical framework for choosing between alternative models has hampered progress, especially for non-experts applying these methods to novel biological systems. Here, we consider cross-validation with a new objective function for estimators of these slow dynamical modes, a generalized matrix Rayleigh quotient (GMRQ), which measures the ability of a rank-m projection operator to capture the slow subspace of the system. It is shown that a variational theorem bounds the GMRQ from above by the sum of the first m eigenvalues of the system’s propagator, but that this bound can be violated when the requisite matrix elements are estimated subject to statistical uncertainty. This overfitting can be detected and avoided through cross-validation. These result make it possible to construct Markov state models for protein dynamics in a way that appropriately captures the tradeoff between systematic and statistical errors. PMID:25833563

  8. Thermodynamic, Kinetic, and Equilibrium Parameters for the Removal of Lead and Cadmium from Aqueous Solutions with Calcium Alginate Beads

    PubMed Central

    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 (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. PMID:24587740

  9. Daily, monthly and seasonal variation in PSA levels and the association with weather parameters.

    PubMed

    Connolly, D; van Leeuwen, P J; Bailie, J; Black, A; Murray, L J; Keane, P F; Gavin, A

    2011-03-01

    PSA levels have shown daily and seasonal variation, although data are conflicting regarding the season with higher PSA levels and the clinical relevance of this. We assessed the correlation of total PSA levels with meteorological data on a daily, weekly, monthly and seasonal basis. Data from 53,224 men aged 45-74 years, with an initial PSA <10.0 ng ml(-1) were correlated with temperature (°C), duration of bright sunshine (hours) and rainfall (mm). There was seasonal variation in PSA levels, with median PSA being higher in spring compared with other seasons (1.18 vs 1.10 ng ml(-1), P = 0.004). Seasonal variation was not apparent when PSA levels were age-adjusted (P = 0.112). Total PSA was not correlated with daily, weekly or monthly hours of sunshine, rainfall or mean temperature. In contrast, age-adjusted PSA varied with weekday, with higher PSA levels on Thursday and Friday compared with other days (1.16 vs 1.10 ng ml(-1), respectively). On multivariate analysis, only age predicted for PSA levels >3.0 ng ml(-1). In conclusion, PSA levels did show seasonal variation, although there was no direct correlation between PSA and any meteorological parameter. The degree of seasonal variation is small and the decision to proceed to prostate biopsy should be independent of season or weather parameters. PMID:20975738

  10. High frequency variations of Earth Rotation Parameters from GPS and GLONASS observations.

    PubMed

    Wei, Erhu; Jin, Shuanggen; Wan, Lihua; Liu, Wenjie; Yang, Yali; Hu, Zhenghong

    2015-01-01

    The Earth's rotation undergoes changes with the influence of geophysical factors, such as Earth's surface fluid mass redistribution of the atmosphere, ocean and hydrology. However, variations of Earth Rotation Parameters (ERP) are still not well understood, particularly the short-period variations (e.g., diurnal and semi-diurnal variations) and their causes. In this paper, the hourly time series of Earth Rotation Parameters are estimated using Global Positioning System (GPS), Global Navigation Satellite System (GLONASS), and combining GPS and GLONASS data collected from nearly 80 sites from 1 November 2012 to 10 April 2014. These new observations with combining different satellite systems can help to decorrelate orbit biases and ERP, which improve estimation of ERP. The high frequency variations of ERP are analyzed using a de-trending method. The maximum of total diurnal and semidiurnal variations are within one milli-arcseconds (mas) in Polar Motion (PM) and 0.5 milli-seconds (ms) in UT1-UTC. The semidiurnal and diurnal variations are mainly related to the ocean tides. Furthermore, the impacts of satellite orbit and time interval used to determinate ERP on the amplitudes of tidal terms are analyzed. We obtain some small terms that are not described in the ocean tide model of the IERS Conventions 2010, which may be caused by the strategies and models we used or the signal noises as well as artifacts. In addition, there are also small differences on the amplitudes between our results and IERS convention. This might be a result of other geophysical excitations, such as the high-frequency variations in atmospheric angular momentum (AAM) and hydrological angular momentum (HAM), which needs more detailed analysis with more geophysical data in the future. PMID:25635416

  11. High Frequency Variations of Earth Rotation Parameters from GPS and GLONASS Observations

    PubMed Central

    Wei, Erhu; Jin, Shuanggen; Wan, Lihua; Liu, Wenjie; Yang, Yali; Hu, Zhenghong

    2015-01-01

    The Earth's rotation undergoes changes with the influence of geophysical factors, such as Earth's surface fluid mass redistribution of the atmosphere, ocean and hydrology. However, variations of Earth Rotation Parameters (ERP) are still not well understood, particularly the short-period variations (e.g., diurnal and semi-diurnal variations) and their causes. In this paper, the hourly time series of Earth Rotation Parameters are estimated using Global Positioning System (GPS), Global Navigation Satellite System (GLONASS), and combining GPS and GLONASS data collected from nearly 80 sites from 1 November 2012 to 10 April 2014. These new observations with combining different satellite systems can help to decorrelate orbit biases and ERP, which improve estimation of ERP. The high frequency variations of ERP are analyzed using a de-trending method. The maximum of total diurnal and semidiurnal variations are within one milli-arcseconds (mas) in Polar Motion (PM) and 0.5 milli-seconds (ms) in UT1-UTC. The semidiurnal and diurnal variations are mainly related to the ocean tides. Furthermore, the impacts of satellite orbit and time interval used to determinate ERP on the amplitudes of tidal terms are analyzed. We obtain some small terms that are not described in the ocean tide model of the IERS Conventions 2010, which may be caused by the strategies and models we used or the signal noises as well as artifacts. In addition, there are also small differences on the amplitudes between our results and IERS convention. This might be a result of other geophysical excitations, such as the high-frequency variations in atmospheric angular momentum (AAM) and hydrological angular momentum (HAM), which needs more detailed analysis with more geophysical data in the future. PMID:25635416

  12. Re-examination of safety parameters using kinetic theory of nano-granular flows

    NASA Astrophysics Data System (ADS)

    Bouillard, Jacques Xavier; Marchal, Philippe; Henry, François; Vignes, Alexis; Dufaud, Olivier; Perrin, Laurent; Plasari, Edouard

    2011-07-01

    The origin of the kinetic theory of granular flow was originally credited to Bagnold [1]. By using a very primitive expression of the particle collision frequency, he derived an expression for the repulsive pressure of the particles in uniform shear flows. His repulsive pressure was proportional to the square of the velocity gradient and the particle diameter and directly proportional to the particle density. This theory was later extended by Savage [2] and Gidaspow [3]. Such theories provide insight on the dependence of the viscosity, and various moduli (elastic, non elastic, viscous...) in terms of the granular temperature and the associated shear-rates. Until recently, such parameters were difficult to measure because of the lack of specifically designed equipment. This challenge was successfully taken up and resolved by P. Marchal of ENSIC who designed a new rheometer for powders (figure 1). This equipment can put in evidence the importance of the granular temperature on the elastic and viscous behaviors of the granular flows. Such rheological behavior is important in risk analysis for nanopowders, because as the nanopowder may be subjected to process shear rates and stresses, its structural and topological changes, in terms of the transformation of agglomerates into primary nanoparticles, have strong impacts on emission factors of nanosized particles that can be released in the environment or into a workplace from such dense-phase nanopowder processes. Such transformation can be analyzed by studying the nano-granular rheological signature of the system. Such risk assessment approach using these new fundamental rheological safety parameters is described in this paper.

  13. [Comparison of kinematic and kinetic parameters between the locomotion patterns in nordic walking, walking and running].

    PubMed

    Kleindienst, F I; Michel, K J; Schwarz, J; Krabbe, B

    2006-03-01

    Based on a higher cardio-pulmonary and cardio-vascular benefit and a promised reduction of mechanical load of the musculoskeletal system Nordic Walking (NW) shows an increased market potential. The present study should investigate whether there are biomechanical differences between the locomotion patterns NW, walking and running. Moreover possible resultant load differences should be determined. Eleven subjects, who were already experienced with the NW-technique, participated in this experiment. The kinematic data were collected using two high-speed camera systems from posterior and from lateral at the same time. Simultaneously the ground reaction forces were recorded. The kinematic and the kinetic data reveal differences between the three analyzed locomotion patterns. For NW as well as walking the mechanical load of the lower extremity is lower compared to running. None of the kinematic parameters suggest a "physiological benefit" of NW compared to walking. Moreover NW shows higher vertical and horizontal forces during landing. Exclusively the lower vertical force peak during push off indicates a lower mechanical load for NW in comparison to walking. Consequently it is questionable is NW -- based on its promised "biomechanical benefits" compared to walking -- should be still recommended for overweight people and for people with existing musculoskeletal problems of the lower limb. PMID:16544213

  14. Isopeptidase activity of human transglutaminase 2: disconnection from transamidation and characterization by kinetic parameters.

    PubMed

    Király, Róbert; Thangaraju, Kiruphagaran; Nagy, Zsófia; Collighan, Russell; Nemes, Zoltán; Griffin, Martin; Fésüs, László

    2016-01-01

    Transglutaminase 2 (TG2) is a multifunctional protein with diverse catalytic activities and biological roles. Its best studied function is the Ca(2+)-dependent transamidase activity leading to formation of γ-glutamyl-ε-lysine isopeptide crosslinks between proteins and γ-glutamyl-amine derivatives. TG2 has a poorly studied isopeptidase activity cleaving these bonds. We have developed and characterised TG2 mutants which are significantly deficient in transamidase activity while have normal or increased isopeptidase activity (W332F) and vice versa (W278F). The W332F mutation led to significant changes of both the K m and the V max kinetic parameters of the isopeptidase reaction of TG2 while its calcium and GTP sensitivity was similar to the wild-type enzyme. The W278F mutation resulted in six times elevated amine incorporating transamidase activity demonstrating the regulatory significance of W278 and W332 in TG2 and that mutations can change opposed activities located at the same active site. The further application of our results in cellular systems may help to understand TG2-driven physiological and pathological processes better and lead to novel therapeutic approaches where an increased amount of crosslinked proteins correlates with the manifestation of degenerative disorders. PMID:26250429

  15. Rate Equations and Kinetic Parameters of the Reactions Involved in Pyrite Oxidation by Thiobacillus ferrooxidans.

    PubMed

    Lizama, H M; Suzuki, I

    1989-11-01

    Rate equations and kinetic parameters were obtained for various reactions involved in the bacterial oxidation of pyrite. The rate constants were 3.5 muM Fe per min per FeS(2) percent pulp density for the spontaneous pyrite dissolution, 10 muM Fe per min per mM Fe for the indirect leaching with Fe, 90 muM O(2) per min per mg of wet cells per ml for the Thiobacillus ferrooxidans oxidation of washed pyrite, and 250 muM O(2) per min per mg of wet cells per ml for the T. ferrooxidans oxidation of unwashed pyrite. The K(m) values for pyrite concentration were similar and were 1.9, 2.5, and 2.75% pulp density for indirect leaching, washed pyrite oxidation by T. ferrooxidans, and unwashed pyrite oxidation by T. ferrooxidans, respectively. The last reaction was competitively inhibited by increasing concentrations of cells, with a K(i) value of 0.13 mg of wet cells per ml. T. ferrooxidans cells also increased the rate of Fe production from Fe plus pyrite. PMID:16348054

  16. Effects of heating rate on slow pyrolysis behavior, kinetic parameters and products properties of moso bamboo.

    PubMed

    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. PMID:25063973

  17. A study of line widths and kinetic parameters of ions in the solar corona

    NASA Astrophysics Data System (ADS)

    Zhao, G. Q.; Wu, D. J.; Wang, C. B.

    2014-10-01

    Solar extreme-ultraviolet (EUV) lines emitted by highly charged ions have been extensively studied to discuss the issue of coronal heating and solar wind acceleration. Based on observations of the polar corona by the SUMER/SOHO spectrometer, this paper investigates the relation between the line widths and kinetic parameters of ions. It is shown that there exists a strongly linear correlation between two variables ( σ/ λ)2 and M -1, where σ, λ and M are the half-width of the observed line profile at , the wavelength and the ion mass, respectively. The Pearson product-moment correlation coefficients exceed 0.9. This finding tends to suggest that the ions from a given height of polar corona have a common temperature and a common non-thermal velocity in terms of existing equation. The temperature and non-thermal velocity are obtained by linear least-square fit. The temperature is around 2.8 MK at heights of 57″ and 102″. The non-thermal velocity is typical 21.6 km s-1 at height of 57″ and 25.2 km s-1 at height of 102″.

  18. Determination of the kinetic parameters of the CALIBAN metallic core reactor from stochastic neutron measurements

    SciTech Connect

    Casoli, P.; Authier, N.; Chapelle, A.

    2012-07-01

    Several experimental devices are operated by the Criticality and Neutron Science Research Dept. of the CEA Valduc Laboratory. One of these is the Caliban metallic core reactor. The purpose of this study is to develop and perform experiments allowing to determinate some of fundamental kinetic parameters of the reactor. The prompt neutron decay constant and particularly its value at criticality can be measured with reactor noise techniques such as Rossi-{alpha} and Feynman variance-to-mean methods. Subcritical, critical, and even supercritical experiments were performed. Fission chambers detectors were put nearby the core and measurements were analyzed with the Rossi-{alpha} technique. A new value of the prompt neutron decay constant at criticality was determined, which allows, using the Nelson number method, new evaluations of the effective delayed neutron fraction and the in core neutron lifetime. As an introduction of this paper, some motivations of this work are given in part 1. In part 2, principles of the noise measurements experiments performed at the CEA Valduc Laboratory are reminded. The Caliban reactor is described in part 3. Stochastic neutron measurements analysis techniques used in this study are then presented in part 4. Results of fission chamber experiments are summarized in part 5. Part 6 is devoted to the current work, improvement of the experimental device using He 3 neutron detectors and first results obtained with it. Finally, conclusions and perspectives are given in part 7. (authors)

  19. Quantification of kinetic parameters for heterotrophic bacteria via respirometry in a hybrid reactor.

    PubMed

    Trapani, Daniele Di; Mannina, Giorgio; Torregrossa, Michele; Viviani, Gaspare

    2010-01-01

    Over the last decade new technologies are emerging even more for wastewater treatment. Among the new technologies, a recent possible solution regards Moving Bed Biofilm Reactors (MBBRs) that represent an effective alternative to conventional processes. More specifically such systems consist in the introduction of plastic elements inside the aerobic reactor as carrier material for the growth of attached biomass. Recently, one of the mostly used alternatives is to couple the Moving Bed Biofilm Reactor (MBBR) process with the conventional activated sludge process, and the resulting process is usually called HMBBR (Hybrid MBBR). In the MBBR process the biofilm grows attached on small plastic elements that are kept in constant motion throughout the entire volume of the reactor. Indeed, in such a system, a competition between the two biomasses, suspended and attached, can arise for the availability of the substrates, leading, as a consequence, to a modification in the biokinetic parameters of the two biomasses, compared to that of a pure suspended or attached biomass process. This paper presents the first results of a study aimed at estimating the kinetic heterotrophic constants in a HMBBR pilot plant using respirometric techniques. The pilot plant was built at the Acqua dei Corsari (Palermo) wastewater treatment plant and consisted of two parallel lines realized in a pre-anoxic scheme, in one of which the carrier material was added to the aerobic reactor with a filling ratio of 30%. PMID:20371934

  20. The Effect of Kinetic Properties on Statistical Variations of Ultrasound Signals Backscattered from Flowing Blood

    NASA Astrophysics Data System (ADS)

    Huang, Chih-Chung; Lin, Yi-Hsun; Wang, Shyh-Hau

    2009-02-01

    Yet very little is known about the effect of “black hole” (BH) phenomenon on backscattering signal statistics under the laminar flow. To further explore this issue, measurements were performed from the porcine blood (with hematocrits of 20 and 50%) circulating in a mock flow loop under various steady flows at velocities ranged from 15 to 122 mm/s using a 10 MHz ultrasonic transducer. Results showed that the BH was apparent for the 50% blood flowing at a low velocity. The BH tended to be decreased with the increase of flow velocity and that it was hardly observed from the 20% blood. The probability density function of signals backscattered from blood tended to distribute as pre-Rayleigh statistics and the Nakagami parameter was less than 1. The spatial distribution of red cell aggregation in the flow tube is a predominant factor leading to statistical variations of ultrasonic backscattering in the flowing blood.

  1. Modeling the sorption kinetic of metsulfuron-methyl on Andisols and Ultisols volcanic ash-derived soils: kinetics parameters and solute transport mechanisms.

    PubMed

    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. PMID:20399011

  2. The diurnal variation of E-F valley parameters from incoherent scatter measurements at Arecibo

    NASA Astrophysics Data System (ADS)

    Mahajan, K. K.; Sethi, N. K.; Pandey, V. K.

    1997-01-01

    The size and shape of the valley region between E and F layers is studied for nighttime conditions by using high resolution electron density profiles measured by the incoherent scatter radar at Arecibo, Puerto Rico, (18.3 degN,66.7 degW). Important valley parameters like width, depth and height of the valley minimum are derived from these measurements. By combining these nighttime results with our earlier daytime model (Mahajan, et. al, 1994), we now present a model for the full diurnal variation of the E-F valley parameters. Comparison with IRI-90 indicates significant differences between our model and the IRI valley model.

  3. Seasonal variations of the humoral immune parameters of European sea bass (Dicentrarchus labrax L.).

    PubMed

    Valero, Yulema; García-Alcázar, Alicia; Esteban, M Ángeles; Cuesta, Alberto; Chaves-Pozo, Elena

    2014-08-01

    Seasonal cycles, mainly due to great variations in the light duration and temperature, are important and modulate several aspects of the animal behavior. In the case of poikilotherms animals such as fish this is very relevant. Thus, temperature changes fish immunity and affects disease resistance. We evaluate in this work the season variations of the European sea bass (Dicentrarchus labrax) humoral innate parameters focusing on winter months, at which the culture of this specie is more difficult. Our results showed that not all the innate immune parameters are depressed by low temperatures. Moreover, some of them are more dependent than others to the season and both temperature and photoperiod are operating together. PMID:24852342

  4. Functional genomics of intraspecific variation in carbon and phosphorus kinetics in Daphnia.

    PubMed

    Chowdhury, Priyanka Roy; Lopez, Jacqueline A; Weider, Lawrence J; Colbourne, John K; Jeyasingh, Punidan D

    2014-08-01

    Understanding how the genome interacts with the environment to produce a diversity of phenotypes is a central challenge in biology. However, we know little about how traits involved in nutrient processing interact with key ecological parameters, such as the supply of mineral nutrients, particularly in animals. The framework of ecological stoichiometry uses information on the content of key elements such as carbon (C) and phosphorus (P) in individuals to predict the success of species. Nevertheless, intraspecific variation in content and the underlying mechanisms that generate such variation has been poorly explored. We studied two genotypes (G1 and G2) of Daphnia pulex that exhibit striking genotype × environment (G × E) interaction in response to shifts in dietary stoichiometry (C:P). G1 had higher fitness under C:P ∼ 100 diet, while G2 performed better in C:P ∼ 800. Dual (14) C/(33) P radiotracer assays show that G1 was more efficient in C processing, while G2 was more efficient in P use. Microarrays revealed that after 3 days of incubation, the genotypes differentially expressed ∼ 25% (7,224) of the total genes on the array under C:P ∼ 100 diet, and ∼ 30% (8,880) of genes under C:P ∼ 800. These results indicate large differences in C and P use between two coexisting genotypes. Importantly, such physiological differences can arise via differential expression of the genome due to alterations in dietary stoichiometry. Basic frameworks such as ecological stoichiometry enable integration of physiological and transcriptomic data, and represent initial steps toward understanding the interplay between fundamental ecological parameters such as nutrient supply and important evolutionary processes such as G × E interactions. PMID:24838198

  5. Effects of variation of environmental parameters on the performance of Resistive Plate Chamber detectors

    NASA Astrophysics Data System (ADS)

    Meghna, K. K.; Biswas, S.; Jash, A.; Chattopadhyay, S.; Saha, S.

    2016-04-01

    Performance of single gap Resistive Plate Chamber (RPC) detectors is investigated under variation of environmental parameters, such as temperature and relative humidity. Operational characteristics of the RPCs depend on both the environmental temperature and the relative humidity. Sensitivity to such dependence is found to be more on temperature rather than the relative humidity. Qualitative interpretation of some of the results obtained is given based on the known properties of the electrode materials and gases used in the detectors.

  6. Diurnal and seasonal variations in the Schumann resonance parameters observed at Chinese observatories

    NASA Astrophysics Data System (ADS)

    Zhou, Hongjuan; Yu, Haiyan; Cao, Bingxia; Qiao, Xiaolin

    2013-06-01

    The Schumann resonances (SRs) are of great significance for probing the global circuit. The diurnal and seasonal variations in mode amplitudes and frequencies of the first four modes of SR magnetic components based on 2 years measurements at the stations located in China are firstly presented here. The frequencies of all the four modes have their maxima during boreal winter and minima during summer, while the mode amplitudes change oppositely. The variations of both frequencies and amplitudes show their strong relationships with the lighting activity in south-east Asia (0800 UT) which is the nearest source to the observatories in China, while the other sources in Africa (1400 UT) and South America (2000 UT) have less effects on the mode amplitudes of both magnetic components. The effect of day-night asymmetry on SR parameters is estimated by a 3D-FDTD model of the Earth-ionosphere cavity with a single pulse traveling around the equator in a day. Two models of the Earth-ionosphere cavity, namely, a symmetric cavity and a cavity with day-night asymmetric conductivity profile are exploited. It is clear that the minima in the diurnal patterns of the mode frequencies near local sunrise/sunset times are mainly related to the migrations of the global lighting activity, not the day-night ionosphere asymmetry. Moreover, it is concluded that the ionosphere-induced variations of SR parameters including mode frequencies and amplitudes are much smaller than the variations resulting from lighting activity.

  7. Haematology and Serum Biochemistry Parameters and Variations in the Eurasian Beaver (Castor fiber).

    PubMed

    Girling, Simon J; Campbell-Palmer, Roisin; Pizzi, Romain; Fraser, Mary A; Cracknell, Jonathan; Arnemo, Jon; Rosell, Frank

    2015-01-01

    Haematology parameters (N = 24) and serum biochemistry parameters (N = 35) were determined for wild Eurasian beavers (Castor fiber), between 6 months - 12 years old. Of the population tested in this study, N = 18 Eurasian beavers were from Norway and N = 17 originating from Bavaria but now living extensively in a reserve in England. All blood samples were collected from beavers via the ventral tail vein. All beavers were chemically restrained using inhalant isoflurane in 100% oxygen prior to blood sampling. Results were determined for haematological and serum biochemical parameters for the species and were compared between the two different populations with differences in means estimated and significant differences being noted. Standard blood parameters for the Eurasian beaver were determined and their ranges characterised using percentiles. Whilst the majority of blood parameters between the two populations showed no significant variation, haemoglobin, packed cell volume, mean cell haemoglobin and white blood cell counts showed significantly greater values (p<0.01) in the Bavarian origin population than the Norwegian; neutrophil counts, alpha 2 globulins, cholesterol, sodium: potassium ratios and phosphorus levels showed significantly (p<0.05) greater values in Bavarian versus Norwegian; and potassium, bile acids, gamma globulins, urea, creatinine and total calcium values levels showed significantly (p<0.05) greater values in Norwegian versus Bavarian relict populations. No significant differences were noted between male and female beavers or between sexually immature (<3 years old) and sexually mature (≥3 years old) beavers in the animals sampled. With Eurasian beaver reintroduction encouraged by legislation throughout Europe, knowledge of baseline blood values for the species and any variations therein is essential when assessing their health and welfare and the success or failure of any reintroduction program. This is the first study to produce base

  8. Fuzzy C-mean clustering on kinetic parameter estimation with generalized linear least square algorithm in SPECT

    NASA Astrophysics Data System (ADS)

    Choi, Hon-Chit; Wen, Lingfeng; Eberl, Stefan; Feng, Dagan

    2006-03-01

    Dynamic Single Photon Emission Computed Tomography (SPECT) has the potential to quantitatively estimate physiological parameters by fitting compartment models to the tracer kinetics. The generalized linear least square method (GLLS) is an efficient method to estimate unbiased kinetic parameters and parametric images. However, due to the low sensitivity of SPECT, noisy data can cause voxel-wise parameter estimation by GLLS to fail. Fuzzy C-Mean (FCM) clustering and modified FCM, which also utilizes information from the immediate neighboring voxels, are proposed to improve the voxel-wise parameter estimation of GLLS. Monte Carlo simulations were performed to generate dynamic SPECT data with different noise levels and processed by general and modified FCM clustering. Parametric images were estimated by Logan and Yokoi graphical analysis and GLLS. The influx rate (K I), volume of distribution (V d) were estimated for the cerebellum, thalamus and frontal cortex. Our results show that (1) FCM reduces the bias and improves the reliability of parameter estimates for noisy data, (2) GLLS provides estimates of micro parameters (K I-k 4) as well as macro parameters, such as volume of distribution (Vd) and binding potential (BP I & BP II) and (3) FCM clustering incorporating neighboring voxel information does not improve the parameter estimates, but improves noise in the parametric images. These findings indicated that it is desirable for pre-segmentation with traditional FCM clustering to generate voxel-wise parametric images with GLLS from dynamic SPECT data.

  9. Kinetic and mass transfer parameters of maltotriose hydrolysis catalyzed by glucoamylase immobilized on macroporous silica and wrapped in pectin gel.

    PubMed

    Gonçalves, L R; Suzuki, G S; Giordano, R C; Giordano, R L

    2001-01-01

    Kinetic and mass transport parameters were estimated for maltotriose hydrolysis using glucoamylase immobilized on macroporous silica and wrapped in pectin gel at 30 degrees C. Free enzyme assays were used to obtain the intrinsic kinetic parameters of a Michaelis-Menten equation, with product inhibition by glucose. The uptake method, based on transient experimental data, was employed in the estimation of mass transfer parameters. Effective diffusivities of maltotriose in pectin gel were estimated by fitting a classical diffusion model to experimental data of maltotriose diffusion into particles of pectin gel in the absence of silica. The effective diffusivities of maltotriose in silica were obtained after fitting a bidisperse model to experimental data of maltotriose hydrolysis using glucoamylase immobilized in silica and wrapped in pectin gel. PMID:11963897

  10. Evaluation of kinetic parameters for enzymatic interesterification synthesis of L-ascorbyl lactate by response surface methodology.

    PubMed

    Gao, Jing; Jiang, Yanjun; Huang, Zhihong; Zhou, Liya

    2007-02-01

    The kinetics of lipase-catalyzed interesterification synthesis of L-ascorbyl lactate was studied. To determine the enzyme kinetic constants of the interesterification, a three-factor and five-level central composite design was used. The factors studied were ethyl lactate concentration, reaction temperature (T), and water content (w). Moreover, a statistical approach called the response surface method (RSM) was used to predict the kinetic constants. Finally, the relationships between the kinetic constants (Vm and Km) and the reaction parameters (T and w) were obtained. To assess the accuracy of the RSM approach for determining Vm and Km, detailed validation experiments were carried out by the conventional approach at four different reaction parameters(35 degrees C, 10 microL; 45 degrees C, 20 microL; 55 degrees C, 15 microL; 65 degrees C, 18 microL). The results indicated that the RSM approach gave reasonable results for the determination of Vm and Km in the range of tested parameters. PMID:17496337

  11. Kinetic parameters for nutrient enhanced crude oil biodegradation in intertidal marine sediments.

    PubMed

    Singh, Arvind K; Sherry, Angela; Gray, Neil D; Jones, D Martin; Bowler, Bernard F J; Head, Ian M

    2014-01-01

    Availability of inorganic nutrients, particularly nitrogen and phosphorous, is often a primary control on crude oil hydrocarbon degradation in marine systems. Many studies have empirically determined optimum levels of inorganic N and P for stimulation of hydrocarbon degradation. Nevertheless, there is a paucity of information on fundamental kinetic parameters for nutrient enhanced crude oil biodegradation that can be used to model the fate of crude oil in bioremediation programmes that use inorganic nutrient addition to stimulate oil biodegradation. Here we report fundamental kinetic parameters (Ks and qmax) for nitrate- and phosphate-stimulated crude oil biodegradation under nutrient limited conditions and with respect to crude oil, under conditions where N and P are not limiting. In the marine sediments studied, crude oil degradation was limited by both N and P availability. In sediments treated with 12.5 mg/g of oil but with no addition of N and P, hydrocarbon degradation rates, assessed on the basis of CO2 production, were 1.10 ± 0.03 μmol CO2/g wet sediment/day which were comparable to rates of CO2 production in sediments to which no oil was added (1.05 ± 0.27 μmol CO2/g wet sediment/day). When inorganic nitrogen was added alone maximum rates of CO2 production measured were 4.25 ± 0.91 μmol CO2/g wet sediment/day. However, when the same levels of inorganic nitrogen were added in the presence of 0.5% P w/w of oil (1.6 μmol P/g wet sediment) maximum rates of measured CO2 production increased more than four-fold to 18.40 ± 1.04 μmol CO2/g wet sediment/day. Ks and qmax estimates for inorganic N (in the form of sodium nitrate) when P was not limiting were 1.99 ± 0.86 μmol/g wet sediment and 16.16 ± 1.28 μmol CO2/g wet sediment/day respectively. The corresponding values for P were 63 ± 95 nmol/g wet sediment and 12.05 ± 1.31 μmol CO2/g wet sediment/day. The qmax values with respect to N and P were not significantly different (P < 0.05). When N and P

  12. Kinetic parameters for nutrient enhanced crude oil biodegradation in intertidal marine sediments

    PubMed Central

    Singh, Arvind K.; Sherry, Angela; Gray, Neil D.; Jones, D. Martin; Bowler, Bernard F. J.; Head, Ian M.

    2014-01-01

    Availability of inorganic nutrients, particularly nitrogen and phosphorous, is often a primary control on crude oil hydrocarbon degradation in marine systems. Many studies have empirically determined optimum levels of inorganic N and P for stimulation of hydrocarbon degradation. Nevertheless, there is a paucity of information on fundamental kinetic parameters for nutrient enhanced crude oil biodegradation that can be used to model the fate of crude oil in bioremediation programmes that use inorganic nutrient addition to stimulate oil biodegradation. Here we report fundamental kinetic parameters (Ks and qmax) for nitrate- and phosphate-stimulated crude oil biodegradation under nutrient limited conditions and with respect to crude oil, under conditions where N and P are not limiting. In the marine sediments studied, crude oil degradation was limited by both N and P availability. In sediments treated with 12.5 mg/g of oil but with no addition of N and P, hydrocarbon degradation rates, assessed on the basis of CO2 production, were 1.10 ± 0.03 μmol CO2/g wet sediment/day which were comparable to rates of CO2 production in sediments to which no oil was added (1.05 ± 0.27 μmol CO2/g wet sediment/day). When inorganic nitrogen was added alone maximum rates of CO2 production measured were 4.25 ± 0.91 μmol CO2/g wet sediment/day. However, when the same levels of inorganic nitrogen were added in the presence of 0.5% P w/w of oil (1.6 μmol P/g wet sediment) maximum rates of measured CO2 production increased more than four-fold to 18.40 ± 1.04 μmol CO2/g wet sediment/day. Ks and qmax estimates for inorganic N (in the form of sodium nitrate) when P was not limiting were 1.99 ± 0.86 μmol/g wet sediment and 16.16 ± 1.28 μmol CO2/g wet sediment/day respectively. The corresponding values for P were 63 ± 95 nmol/g wet sediment and 12.05 ± 1.31 μmol CO2/g wet sediment/day. The qmax values with respect to N and P were not significantly different (P < 0.05). When N and P

  13. Interaction between chitosan and uranyl ions. Role of physical and physicochemical parameters on the kinetics of sorption

    SciTech Connect

    Piron, E. |; Accominotti, M.; Domard, A.

    1997-03-19

    This work corresponds to the first part of our studies on the interactions between chitosan particles dispersed in water and uranyl ions. The measurements were obtained by ICP, and we considered the role of various physical and physicochemical parameters related to chitosan. We showed that the crystallinity, the particle dimensions, and the swelling in water of chitosan are parameters which are connected together and govern the kinetic laws of metal diffusion and sorption. The molecular mobility of the polymer chains is then essential parameter. 31 refs., 5 figs., 3 tabs.

  14. Tolerable Variation in Item Parameter Estimates for Linear and Adaptive Computer-Based Testing. Research Report No. 04-28

    ERIC Educational Resources Information Center

    Rizavi, Saba; Way, Walter D.; Davey, Tim; Herbert, Erin

    2004-01-01

    Item parameter estimates vary for a variety of reasons, including estimation error, characteristics of the examinee samples, and context effects (e.g., item location effects, section location effects, etc.). Although we expect variation based on theory, there is reason to believe that observed variation in item parameter estimates exceeds what…

  15. Investigation of thermoluminescence and kinetic parameters of CaMgB2O5: Dy3+ nanophosphor

    NASA Astrophysics Data System (ADS)

    Manhas, M.; Kumar, Vinay; Ntwaeaborwa, O. M.; Swart, H. C.

    2016-05-01

    In this paper, thermoluminescence (TL) properties of Dy3+ (1.5 mol %) doped CaMgB2O5 nanophosphor after being exposed to ultraviolet (UV) radiations (λ=254nm) were investigated. In UV exposed samples, the thermoluminescence glow curve consists of a broad glow peak located at 380 K with a small shoulder at 507 K. A shift in glow peak temperature from 367 K to 380 K after the UV exposure for 80 min was observed, which clearly shows that glow peaks follow the second order kinetics. The TL intensity of the peaks increases with an increase in the exposure time of UV rays (10-180 min). The TL Anal program was used to analyze the glow curve. The kinetic parameters such as activation energy (E), the frequency factor (s) and the order of kinetics (b) were calculated for CaMgB2O5: Dy3+ nanophosphors.

  16. A new approach to relate kinetic parameters, composition and temperatures of igneous minerals: the case of Villarrica Volcano 1971 eruption

    NASA Astrophysics Data System (ADS)

    Contreras, C.; Parada, M. A.; Morgado, E. E.; Castruccio, A.

    2014-12-01

    This contribution provides a new approach to calculate the plagioclase composition of a given igneous rock based on kinetics parameters of crystallization obtained from CSD analyses of plagioclase. The procedure we use includes the following steps: 1) determination of the effective rates of crystal growth and nucleation based on the maximum time interval of mineral crystallization obtained from the CSD segment with the minimum slope and extrapolated to rest of the segments; 2) calculation of the total crystallization time; 3) determination of the time-dependent variation of plagioclase volume fraction based on crystal population density and CSD slopes; 4) calculation of the ideal rates of crystal growth and nucleation; 5) determination of temperature of plagioclase crystallization as a function of the ideal crystal growth rate; 6) determination of plagioclase composition as a function of the ideal crystal growth rate. We apply our model for plagioclase of 17 samples of The Villarrica Volcano 1971 eruption lava flow. All CSD show two segments with a break at 0.3 mm. The first segment is interpreted as the syn-eruptive crystallization and the second as the within-reservoir crystallization. An interval of 1.5 years as a maximum crystallization time for the syn-eruptive stage was estimated from Cashman's (1993) expression. Crystal growth rates in the reservoir stage took place during two stages. The first stage varies from 10^-8.9 to 10^-9.4 mm s-1 and the second one varied from 10^-9.4 to 10^-9.1 mm s-1. Finally, the crystal growth rate as high as 10^-7.8 mm s-1 were estimated for the syn-eruptive stage. Nucleation rates varies exponentially from 10^-13 to 10^-8 s-1 in the reservoir stage and from 10^-8 to 10^-1 s^-1 in the syn-eruptive stage. The total crystallization interval varies from 120 to 390 years. A mean total volume fraction of plagioclase of 0.55 was obtained (0.98 for all minerals) whereas a mean value of 0.054 was obtained at the onset of the eruption (0

  17. Determination of char combustion kinetics parameters: Comparison of point detector and imaging-based particle-sizing pyrometry

    NASA Astrophysics Data System (ADS)

    Schiemann, Martin; Geier, Manfred; Shaddix, Christopher R.; Vorobiev, Nikita; Scherer, Viktor

    2014-07-01

    In this study, the char burnout characteristics of two German coals (a lignite and a high-volatile bituminous coal) were investigated using two different experimental configurations and optical techniques in two distinct laboratories for measurement of temperature and size of burning particles. The optical diagnostic hardware is quite different in the two systems, but both perform two-color pyrometry and optical sizing measurements on individual particles burning in isolation from each other in high-temperature laminar flows to characterize the char consumption kinetics. The performance of the specialized systems is compared for two different combustion atmospheres (with 6.6 and 12 vol.% O2) and gas temperatures between 1700 and 1800 K. The measured particle temperatures and diameters are converted to char burning rate parameters for several residence times during the course of the particles' burnout. The results confirm that comparable results are obtained with the two configurations, although higher levels of variability in the measured data were observed in the imaging-based pyrometer setup. Corresponding uncertainties in kinetics parameters were larger, and appear to be more sensitive to systematic measurement errors when lower oxygen contents are used in the experiments. Consequently, burnout experiments in environments with sufficiently high O2 contents may be used to measure reliable char burning kinetics rates. Based on simulation results for the two coals, O2 concentrations in the range 10%-30% are recommended for kinetic rate measurements on 100 μm particles.

  18. Arsenic Species in Chicken Breast: Temporal Variations of Metabolites, Elimination Kinetics, and Residual Concentrations

    PubMed Central

    Liu, Qingqing; Peng, Hanyong; Lu, Xiufen; Zuidhof, Martin J.; Li, Xing-Fang; Le, X. Chris

    2016-01-01

    Background: Chicken meat has the highest per capita consumption among all meat types in North America. The practice of feeding 3-nitro-4-hydroxyphenylarsonic acid (Roxarsone, Rox) to chickens lasted for more than 60 years. However, the fate of Rox and arsenic metabolites remaining in chicken are poorly understood. Objectives: We aimed to determine the elimination of Rox and metabolites from chickens and quantify the remaining arsenic species in chicken meat, providing necessary information for meaningful exposure assessment. Methods: We have conducted a 35-day feeding experiment involving 1,600 chickens, of which half were control and the other half were fed a Rox-supplemented diet for the first 28 days and then a Rox-free diet for the final 7 days. We quantified the concentrations of individual arsenic species in the breast meat of 229 chickens. Results: Rox, arsenobetaine, arsenite, monomethylarsonic acid, dimethylarsinic acid, and a new arsenic metabolite, were detected in breast meat from chickens fed Rox. The concentrations of arsenic species, except arsenobetaine, were significantly higher in the Rox-fed than in the control chickens. The half-lives of elimination of these arsenic species were 0.4–1 day. Seven days after termination of Rox feeding, the concentrations of arsenite (3.1 μg/kg), Rox (0.4 μg/kg), and a new arsenic metabolite (0.8 μg/kg) were significantly higher in the Rox-fed chickens than in the control. Conclusion: Feeding of Rox to chickens increased the concentrations of five arsenic species in breast meat. Although most arsenic species were excreted rapidly when the feeding of Rox stopped, arsenic species remaining in the Rox-fed chickens were higher than the background levels. Citation: Liu Q, Peng H, Lu X, Zuidhof MJ, Li XF, Le XC. 2016. Arsenic species in chicken breast: temporal variations of metabolites, elimination kinetics, and residual concentrations. Environ Health Perspect 124:1174–1181; http://dx.doi.org/10.1289/ehp

  19. Simulations of a epidemic model with parameters variation analysis for the dengue fever

    NASA Astrophysics Data System (ADS)

    Jardim, C. L. T. F.; Prates, D. B.; Silva, J. M.; Ferreira, L. A. F.; Kritz, M. V.

    2015-09-01

    Mathematical models can be widely found in the literature for describing and analyzing epidemics. The models that use differential equations to represent mathematically such description are specially sensible to parameters involved in the modelling. In this work, an already developed model, called SIR, is analyzed when applied to a scenario of a dengue fever epidemic. Such choice is powered by the existence of useful tools presented by a variation of this original model, which allow an inclusion of different aspects of the dengue fever disease, as its seasonal characteristics, the presence of more than one strain of the vector and of the biological factor of cross-immunity. The analysis and results interpretation are performed through numerical solutions of the model in question, and a special attention is given to the different solutions generated by the use of different values for the parameters present in this model. Slight variations are performed either dynamically or statically in those parameters, mimicking hypothesized changes in the biological scenario of this simulation and providing a source of evaluation of how those changes would affect the outcomes of the epidemic in a population.

  20. An alternating direction algorithm for total variation reconstruction of distributed parameters.

    PubMed

    Brás, Nuno B; Bioucas-Dias, J; Martins, Raul C; Serra, A C

    2012-06-01

    Augmented Lagrangian variational formulations and alternating optimization have been adopted to solve distributed parameter estimation problems. The alternating direction method of multipliers (ADMM) is one of such formulations/optimization methods. Very recently, the number of applications of the ADMM, or variants of it, to solve inverse problems in image and signal processing has increased at an exponential rate. The reason for this interest is that ADMM decomposes a difficult optimization problem into a sequence of much simpler problems. In this paper, we use the ADMM to reconstruct piecewise-smooth distributed parameters of elliptical partial differential equations from noisy and linear (blurred) observations of the underlying field. The distributed parameters are estimated by solving an inverse problem with total variation (TV) regularization. The proposed instance of the ADMM solves, in each iteration, an l(2) and a decoupled l(2) - l(1) optimization problems. An operator splitting is used to simplify the treatment of the TV regularizer, avoiding its smooth approximation and yielding a simple yet effective ADMM reconstruction method compared with previously proposed approaches. The competitiveness of the proposed method, with respect to the state-of-the-art, is illustrated in simulated 1-D and 2-D elliptical equation problems, which are representative of many real applications. PMID:22345538

  1. Sensitivity analysis and parameter estimation for distributed hydrological modeling: potential of variational methods

    NASA Astrophysics Data System (ADS)

    Castaings, W.; Dartus, D.; Le Dimet, F.-X.; Saulnier, G.-M.

    2009-04-01

    Variational methods are widely used for the analysis and control of computationally intensive spatially distributed systems. In particular, the adjoint state method enables a very efficient calculation of the derivatives of an objective function (response function to be analysed or cost function to be optimised) with respect to model inputs. In this contribution, it is shown that the potential of variational methods for distributed catchment scale hydrology should be considered. A distributed flash flood model, coupling kinematic wave overland flow and Green Ampt infiltration, is applied to a small catchment of the Thoré basin and used as a relatively simple (synthetic observations) but didactic application case. It is shown that forward and adjoint sensitivity analysis provide a local but extensive insight on the relation between the assigned model parameters and the simulated hydrological response. Spatially distributed parameter sensitivities can be obtained for a very modest calculation effort (~6 times the computing time of a single model run) and the singular value decomposition (SVD) of the Jacobian matrix provides an interesting perspective for the analysis of the rainfall-runoff relation. For the estimation of model parameters, adjoint-based derivatives were found exceedingly efficient in driving a bound-constrained quasi-Newton algorithm. The reference parameter set is retrieved independently from the optimization initial condition when the very common dimension reduction strategy (i.e. scalar multipliers) is adopted. Furthermore, the sensitivity analysis results suggest that most of the variability in this high-dimensional parameter space can be captured with a few orthogonal directions. A parametrization based on the SVD leading singular vectors was found very promising but should be combined with another regularization strategy in order to prevent overfitting.

  2. Study of gain variation as a function of physical parameters of GEM foil

    NASA Astrophysics Data System (ADS)

    Das, Supriya

    2016-07-01

    The ALICE experiment at LHC has planned to upgrade the TPC by replacing the MWPC with GEM based detecting elements to restrict the IBF to a tolerable value. However the variation of the gain as a function of physical parameters of industrially produced large size GEM foils is needed to be studied as a part of the QA procedure for the detector. The size of the electron avalanche and consequently the gain for GEM based detectors depend on the electric field distribution inside the holes. Geometry of a hole plays an important role in defining the electric field inside it. In this work we have studied the variation of the gain as a function of the hole diameters using Garfield++ simulation package.

  3. Long-period variations of wind parameters in the mesopause region and the solar cycle dependence

    NASA Technical Reports Server (NTRS)

    Greisiger, K. M.; Schminder, R.; Kuerschner, D.

    1987-01-01

    The solar cycle dependence of wind parameters below 100 km on the basis of long term continuous ionospheric drift measurements in the low frequency range is discussed. For the meridional prevailing wind no significant variation was found. The same comparison as for winter was done for summer where the previous investigations gave no correlation. Now the radar meteor wind measurement values, too, showed a significant negative correlation of the zonal prevailing wind with solar activity for the years 1976 to 1983. The ionospheric drift measurement results of Collm have the same tendency but a larger dispersion due to the lower accuracy of the harmonic analysis because of the shorter daily measuring interval in summer. Continuous wind observations in the upper mesopause region over more than 20 years revealed distinct long term variations, the origin of which cannot be explained with the present knowledge.

  4. Temporal variation of tidal parameters in superconducting gravimeter time-series

    NASA Astrophysics Data System (ADS)

    Meurers, Bruno; Van Camp, Michel; Francis, Olivier; Pálinkáš, Vojtech

    2016-04-01

    Analysing independent 1-yr data sets of 10 European superconducting gravimeters (SG) reveals statistically significant temporal variations of M2 tidal parameters. Both common short-term (<2 yr) and long-term (>2 yr) features are identified in all SG time-series but one. The averaged variations of the amplitude factor are about 0.2‰. The path of load vector variations equivalent to the temporal changes of tidal parameters suggests the presence of an 8.85 yr modulation (lunar perigee). The tidal waves having the potential to modulate M2 with this period belong to the 3rd degree constituents. Their amplitude factors turn out to be much closer to body tide model predictions than that of the main 2nd degree M2, which indicates ocean loading for 3rd degree waves to be less prominent than for 2nd degree waves within the M2 group. These two different responses to the loading suggest that the observed modulation is more due to insufficient frequency resolution of limited time-series rather than to time variable loading. Presently, SG gravity time-series are still too short to prove if time variable loading processes are involved too as in case of the annual M2 modulation known to appear for analysis intervals of less than 1 yr. Whatever the variations are caused by, they provide the upper accuracy limit for earth model validation and permit estimating the temporal stability of SG scale factors and assessing the quality of gravity time-series.

  5. Linear and nonlinear response to parameter variations in a mesoscale model

    NASA Astrophysics Data System (ADS)

    Hacker, J.; Snyder, C.

    2009-04-01

    simple lagged-regression techniques. Only one of the parameters that are perturbed leads to noticeable changes in model bias. The response to each parameter is different in magnitude and direction in the model state space; it does not simply follow a common sensitivity pattern. We deduce a nonlinear response from lack of measurable linear sensitivity and also by noting departures from statistical normality in the response. We argue that a linear relationship between parameters and predictions is potentially useful for parameter estimation via data assimilation. The fact that this linear relationship varies in space and time suggests that the parameters themselves should be spatially and temporally varying. Parameters can then be treated as unobserved variables with spatial and temporal scales inferred from the scales of variation of the parameter-state relationships. One implication for ensemble data assimilation, for example, is that the number of ensemble members may need to be large, or some form of localization may need to be imposed, to effectively estimate parameters.

  6. Fourier domain closed-form formulas for estimation of kinetic parameters in reversible multi-compartment models

    PubMed Central

    2012-01-01

    Background Compared with static imaging, dynamic emission computed tomographic imaging with compartment modeling can quantify in vivo physiologic processes, providing useful information about molecular disease processes. Dynamic imaging involves estimation of kinetic rate parameters. For multi-compartment models, kinetic parameter estimation can be computationally demanding and problematic with local minima. Methods This paper offers a new perspective to the compartment model fitting problem where Fourier linear system theory is applied to derive closed-form formulas for estimating kinetic parameters for the two-compartment model. The proposed Fourier domain estimation method provides a unique solution, and offers very different noise response as compared to traditional non-linear chi-squared minimization techniques. Results The unique feature of the proposed Fourier domain method is that only low frequency components are used for kinetic parameter estimation, where the DC (i.e., the zero frequency) component in the data is treated as the most important information, and high frequency components that tend to be corrupted by statistical noise are discarded. Computer simulations show that the proposed method is robust without having to specify the initial condition. The resultant solution can be fine tuned using the traditional iterative method. Conclusions The proposed Fourier-domain estimation method has closed-form formulas. The proposed Fourier-domain curve-fitting method does not require an initial condition, it minimizes a quadratic objective function and a closed-form solution can be obtained. The noise is easier to control, simply by discarding the high frequency components, and emphasizing the DC component. PMID:22995548

  7. Variation of photon interaction parameters with energy for some Cu-Pb alloys

    SciTech Connect

    Singh, Tejbir Kaur, Sarpreet; Kaur, Parminder; Kaur, Harvinder; Singh, Parjit S.

    2015-08-28

    Various photon interaction parameters (mass attenuation coefficients, effective atomic numbers and effective electron numbers) have been computed for different compositions of Cu-Pb alloys in the wide energy regime of 1 keV to 100 GeV. The mass attenuation coefficients have been computed using mixture rule with the help of WinXCom (mass attenuation coefficient database for elements). The variation of mass attenuation coefficients, effective atomic numbers and electron density has been analysed and discussed in terms of dominance of different photon interaction processes viz. Compton scattering, photoelectric effect and pair production.

  8. A normalized wave number variation parameter for acoustic black hole design.

    PubMed

    Feurtado, Philip A; Conlon, Stephen C; Semperlotti, Fabio

    2014-08-01

    In recent years, the concept of the Acoustic Black Hole has been developed as an efficient passive, lightweight absorber of bending waves in plates and beams. Theory predicts greater absorption for a higher thickness taper power. However, a higher taper power also increases the violation of an underlying theory smoothness assumption. This paper explores the effects of high taper power on the reflection coefficient and spatial change in wave number and discusses the normalized wave number variation as a spatial design parameter for performance, assessment, and optimization. PMID:25096139

  9. Variation of photon interaction parameters with energy for some Cu-Pb alloys

    NASA Astrophysics Data System (ADS)

    Singh, Tejbir; Kaur, Sarpreet; Kaur, Parminder; Kaur, Harvinder; Singh, Parjit S.

    2015-08-01

    Various photon interaction parameters (mass attenuation coefficients, effective atomic numbers and effective electron numbers) have been computed for different compositions of Cu-Pb alloys in the wide energy regime of 1 keV to 100 GeV. The mass attenuation coefficients have been computed using mixture rule with the help of WinXCom (mass attenuation coefficient database for elements). The variation of mass attenuation coefficients, effective atomic numbers and electron density has been analysed and discussed in terms of dominance of different photon interaction processes viz. Compton scattering, photoelectric effect and pair production.

  10. Monoculture parameters successfully predict coculture growth kinetics of Bacteroides thetaiotaomicron and two Bifidobacterium strains.

    PubMed

    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. PMID:25282609

  11. Effects of Multiple-Bond Ruptures on Kinetic Parameters Extracted from Force Spectroscopy Measurements: Revisiting Biotin-Streptavidin Interactions

    PubMed Central

    Guo, Senli; Ray, Chad; Kirkpatrick, Andrea; Lad, Nimit; Akhremitchev, Boris B.

    2008-01-01

    Force spectroscopy measurements of the rupture of the molecular bond between biotin and streptavidin often results in a wide distribution of rupture forces. We attribute the long tail of high rupture forces to the nearly simultaneous rupture of more than one molecular bond. To decrease the number of possible bonds, we employed hydrophilic polymeric tethers to attach biotin molecules to the atomic force microscope probe. It is shown that the measured distributions of rupture forces still contain high forces that cannot be described by the forced dissociation from a deep potential well. We employed a recently developed analytical model of simultaneous rupture of two bonds connected by polymer tethers with uneven length to fit the measured distributions. The resulting kinetic parameters agree with the energy landscape predicted by molecular dynamics simulations. It is demonstrated that when more than one molecular bond might rupture during the pulling measurements there is a noise-limited range of probe velocities where the kinetic parameters measured by force spectroscopy correspond to the true energy landscape. Outside this range of velocities, the kinetic parameters extracted by using the standard most probable force approach might be interpreted as artificial energy barriers that are not present in the actual energy landscape. Factors that affect the range of useful velocities are discussed. PMID:18621812

  12. Anthropometric Indices Associated with Variation in Cardiovascular Parameters among Primary School Pupils in Ile-Ife

    PubMed Central

    Abiodun, Adedeji G.; Egwu, Michael O.; Adedoyin, Rufus A.

    2011-01-01

    Purpose. This study investigated the anthropometric indices associated with variations in cardiovascular parameters among primary school pupils in Ile-Ife. Method. One thousand and twenty-six pupils (age range 6–14 years, mean age 10.12 years) from ten schools were recruited with parents' informed consent. Anthropometric (Height (Ht), Weight (Wt), Abdominal Circumference (AC)) and cardiovascular (Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Heart Rate (HR)) parameters were measured using standard instruments and procedures. Blood pressure (BP) was measured after ten minutes of quiet sitting. Body Mass Index (BMI), Rate Pressure Product (RPP) and Pulse Pressure (PP) were estimated. Results. Age, Ht, Wt, BMI, and AC correlated significantly (P < .01) with BP and PP. AC and BMI were predictors of BP, HR, RPP, and PP. Conclusion. Significant correlations exist between age, Ht, Wt, BMI, AC, and BP with weight being a more viable predictor of SBP and age a more viable predictor of DBP. PMID:21747972

  13. Atmospheric and ionospheric electrical parameter variations inferred from sub - ionospheric seismo - electromagnetic VLF/LF observations

    NASA Astrophysics Data System (ADS)

    Schwingenschuh, K.; Eichelberger, H. U.; Besser, B. P.; Prattes, G.; Boudjada, M. Y.; Stangl, G.; Wolbang, D.; Rozhnoi, A.; Solovieva, M.; Biagi, P. F.; Friedrich, M.; Biernat, H.; Hayakawa, M.

    2012-04-01

    Subionospheric VLF/LF radio links are an essential tool to investigate seismo - electromagnetic phenomena. The propagation of very low (VLF) and low frequency (LF) frequency radio waves is mainly controlled by the index of refraction and electrical conductivity in the waveguide between the surface and the ionosphere. These parameters can be disturbed during seismic active periods by the lithospheric - atmospheric - ionospheric coupling. The signals of various navigational and time service transmitters are received by a European network of VLF/LF receivers. Several methods have been developed to analyse the received VLF/LF amplitude and phase in order to get information on the seismic activity along the radio path. We present a simple model for the estimation of the VLF/LF radio wave propagation parameters using mainly the amplitude observations of receivers in Italy, Austria and Russia. The main emphasis is on the L'Aquila earthquake from April 2009 with a magnitude of 6.3. This event has been observed with ground based VLF/LF radio links as well as with satellite VLF receivers. The influence of the electrophysical parameters in the immediate vicinity of the active-seismic region on ionospheric parameters is a hot debated issue, where definite physical answers are still expected to be found. Its consequences for the VLF/LF propagation in the sub-ionospheric waveguide are theoretically not well understood up to now, although empirically the issue is well established. For the analysis of pre-seismic activity the systematic variation of the terminator time (TT) and the night time amplitude variations (residual method) seem to be an important indicator. Therefore we studied theoretically the propagation and the influence of ionospheric parameter changes on the VLF/LF mode conversion at the solar terminator and near the seismic region. Our method is based on analytical models of Ledinegg et al. (1982). In particular, we will present prelininary results of the influence

  14. A multiscale variational approach to the kinetics of viscous classical liquids: The coarse-grained mean field approximation

    SciTech Connect

    Sereda, Yuriy V.; Ortoleva, Peter J.

    2014-04-07

    A closed kinetic equation for the single-particle density of a viscous simple liquid is derived using a variational method for the Liouville equation and a coarse-grained mean-field (CGMF) ansatz. The CGMF ansatz is based on the notion that during the characteristic time of deformation a given particle interacts with many others so that it experiences an average interaction. A trial function for the N-particle probability density is constructed using a multiscale perturbation method and the CGMF ansatz is applied to it. The multiscale perturbation scheme is based on the ratio of the average nearest-neighbor atom distance to the total size of the assembly. A constraint on the initial condition is discovered which guarantees that the kinetic equation is mass-conserving and closed in the single-particle density. The kinetic equation has much of the character of the Vlasov equation except that true viscous, and not Landau, damping is accounted for. The theory captures condensation kinetics and takes much of the character of the Gross-Pitaevskii equation in the weak-gradient short-range force limit.

  15. Quantifying the performance of in vivo portal dosimetry in detecting four types of treatment parameter variations

    SciTech Connect

    Bojechko, C.; Ford, E. C.

    2015-12-15

    Purpose: To quantify the ability of electronic portal imaging device (EPID) dosimetry used during treatment (in vivo) in detecting variations that can occur in the course of patient treatment. Methods: Images of transmitted radiation from in vivo EPID measurements were converted to a 2D planar dose at isocenter and compared to the treatment planning dose using a prototype software system. Using the treatment planning system (TPS), four different types of variability were modeled: overall dose scaling, shifting the positions of the multileaf collimator (MLC) leaves, shifting of the patient position, and changes in the patient body contour. The gamma pass rate was calculated for the modified and unmodified plans and used to construct a receiver operator characteristic (ROC) curve to assess the detectability of the different parameter variations. The detectability is given by the area under the ROC curve (AUC). The TPS was also used to calculate the impact of the variations on the target dose–volume histogram. Results: Nine intensity modulation radiation therapy plans were measured for four different anatomical sites consisting of 70 separate fields. Results show that in vivo EPID dosimetry was most sensitive to variations in the machine output, AUC = 0.70 − 0.94, changes in patient body habitus, AUC = 0.67 − 0.88, and systematic shifts in the MLC bank positions, AUC = 0.59 − 0.82. These deviations are expected to have a relatively small clinical impact [planning target volume (PTV) D{sub 99} change <7%]. Larger variations have even higher detectability. Displacements in the patient’s position and random variations in MLC leaf positions were not readily detectable, AUC < 0.64. The D{sub 99} of the PTV changed by up to 57% for the patient position shifts considered here. Conclusions: In vivo EPID dosimetry is able to detect relatively small variations in overall dose, systematic shifts of the MLC’s, and changes in the patient habitus. Shifts in the

  16. Variational estimation of process parameters in a simplified atmospheric general circulation model

    NASA Astrophysics Data System (ADS)

    Lv, Guokun; Koehl, Armin; Stammer, Detlef

    2016-04-01

    Parameterizations are used to simulate effects of unresolved sub-grid-scale processes in current state-of-the-art climate model. The values of the process parameters, which determine the model's climatology, are usually manually adjusted to reduce the difference of model mean state to the observed climatology. This process requires detailed knowledge of the model and its parameterizations. In this work, a variational method was used to estimate process parameters in the Planet Simulator (PlaSim). The adjoint code was generated using automatic differentiation of the source code. Some hydrological processes were switched off to remove the influence of zero-order discontinuities. In addition, the nonlinearity of the model limits the feasible assimilation window to about 1day, which is too short to tune the model's climatology. To extend the feasible assimilation window, nudging terms for all state variables were added to the model's equations, which essentially suppress all unstable directions. In identical twin experiments, we found that the feasible assimilation window could be extended to over 1-year and accurate parameters could be retrieved. Although the nudging terms transform to a damping of the adjoint variables and therefore tend to erases the information of the data over time, assimilating climatological information is shown to provide sufficient information on the parameters. Moreover, the mechanism of this regularization is discussed.

  17. An analytical method for Mathieu oscillator based on method of variation of parameter

    NASA Astrophysics Data System (ADS)

    Li, Xianghong; Hou, Jingyu; Chen, Jufeng

    2016-08-01

    A simple, but very accurate analytical method for forced Mathieu oscillator is proposed, the idea of which is based on the method of variation of parameter. Assuming that the time-varying parameter in Mathieu oscillator is constant, one could easily obtain its accurately analytical solution. Then the approximately analytical solution for Mathieu oscillator could be established after substituting periodical time-varying parameter for the constant one in the obtained accurate analytical solution. In order to certify the correctness and precision of the proposed analytical method, the first-order and ninth-order approximation solutions by harmonic balance method (HBM) are also presented. The comparisons between the results by the proposed method with those by the numerical simulation and HBM verify that the results by the proposed analytical method agree very well with those by the numerical simulation. Moreover, the precision of the proposed new analytical method is not only higher than the approximation solution by first-order HBM, but also better than the approximation solution by the ninth-order HBM in large ranges of system parameters.

  18. Vibration control of an MR vehicle suspension system considering both hysteretic behavior and parameter variation

    NASA Astrophysics Data System (ADS)

    Choi, Seung-Bok; Seong, Min-Sang; Ha, Sung-Hoon

    2009-12-01

    This paper presents vibration control responses of a controllable magnetorheological (MR) suspension system considering the two most important characteristics of the system; the field-dependent hysteretic behavior of the MR damper and the parameter variation of the suspension. In order to achieve this goal, a cylindrical MR damper which is applicable to a middle-sized passenger car is designed and manufactured. After verifying the damping force controllability, the field-dependent hysteretic behavior of the MR damper is identified using the Preisach hysteresis model. The full-vehicle suspension model is then derived by considering vertical, pitch and roll motions. An H_{\\infty } controller is designed by treating the sprung mass of the vehicle as a parameter variation and integrating it with the hysteretic compensator which produces additional control input. In order to demonstrate the effectiveness and robustness of the proposed control system, the hardware-in-the-loop simulation (HILS) methodology is adopted by integrating the suspension model with the proposed MR damper. Vibration control responses of the vehicle suspension system such as vertical acceleration are evaluated under both bump and random road conditions.

  19. Normal variation in cortical osteocyte lacunar parameters in healthy young males

    PubMed Central

    Carter, Yasmin; Suchorab, Jessica L; Thomas, C David L; Clement, John G; Cooper, David M L

    2014-01-01

    The most abundant cell in bone, osteocytes form an interconnected system upon which the regulation of healthy bone relies. Although the complete nature of the role of osteocytes has yet to be defined, they are generally accepted to play a part in the sensing of load and the initiation of damage repair. A previous study conducted by our group identified variation of up to 30% in osteocyte lacunar density and morphological parameters between regions of a single cross-section of human femoral shaft; that study, however, was limited to a single individual. The aim of the current study was to determine whether this pattern consistently occurs in healthy young male femora. Anterior, posterior, medial and lateral blocks were prepared from the proximal femoral shaft of seven males and synchrotron radiation micro-CT imaged. Average lacunar densities (± SD) from the anterior, posterior, medial and lateral regions were 23 394 ± 1705, 30 180 ± 4860, 35 946 ± 5990 and 29 678 ± 6081 lacunae per mm3 of bone tissue, respectively. These values were significantly different between the anterior and both the medial and posterior regions (P < 0.05). The density of the combined anterior and posterior regions was also significantly lower (P = 0.006) than the density of the combined medial and lateral regions. Although no difference was found in predominant orientation, shape differences were found; with the combined anterior-posterior regions having lacunae that were significantly more elongated and less flat than the combined medial-lateral values (P < 0.001). As expected, in this larger study, there was a dramatic difference in lacunar density between the medial and anterior region (up to ∼ 54%). The study clearly demonstrates that the high variation seen in osteocyte lacunar density as well as other lacunar parameters, noted in a number of biomechanical, age and pathology studies, are well within the range of normal variation; however, the reasons for and

  20. Controls on ostracod valve geochemistry, Part 1: Variations of environmental parameters in ostracod (micro-)habitats

    NASA Astrophysics Data System (ADS)

    Decrouy, Laurent; Vennemann, Torsten Walter; Ariztegui, Daniel

    2011-11-01

    The variations of environmental conditions ( T°, pH, δ 13C DIC, [DIC], δ 18O, Mg/Ca, and Sr/Ca) of ostracod habitats were examined to determine the controls of environmental parameters on the chemical and isotopic composition of ostracod valves. Results of a one-year monitoring of environmental parameters at five sites, with depths of between 2 and 70 m, in Lake Geneva indicate that in littoral to sub-littoral zones (2, 5, and 13 m), the chemical composition of bottom water varies seasonally in concert with changes in temperature and photosynthetic activity. An increase of temperature and photosynthetic activity leads to an increase in δ 13C values of DIC and to precipitation of authigenic calcite, which results in a concomitant increase of Mg/Ca and Sr/Ca ratios of water. In deeper sites (33 and 70 m), the composition of bottom water remains constant throughout the year and isotopic values and trace element contents are similar to those of deep water within the lake. The chemical composition of interstitial pore water also does not reflect seasonal variations but is controlled by calcite dissolution, aerobic respiration, anaerobic respiration with reduction of sulphate and/or nitrate, and methanogenesis that may occur in the sediment pores. Relative influence of each of these factors on the pore water geochemistry depends on sediment thickness and texture, oxygen content in bottom as well as pore water. Variations of chemical compositions of the ostracod valves of this study vary according to the specific ecology of the ostracod species analysed, that is its life-cycle and its (micro-)habitat. Littoral species have compositions that are related to the seasonal variations of temperature, δ 13C values of DIC, and of Mg/Ca and Sr/Ca ratios of water. In contrast, the compositions of profundal species are largely controlled by variations of pore fluids along sediment depth profiles according to the specific depth preference of the species. The control on the

  1. The influence of different space-related physiological variations on exercise capacity determined by oxygen uptake kinetics

    NASA Astrophysics Data System (ADS)

    Stegemann, J.

    Oxygen uptake kinetics, following defined variations of work load changes allow to estimate the contribution of aerob and anaerob energy supply which is the base for determining work capacity. Under the aspect of long duration missions with application of adequate dosed countermeasures, a reliable estimate of the astronaut's work capacity is important to adjust the necessary inflight training. Since the kinetics of oxygen uptake originate in the working muscle group itself, while measurements are performed at the mouth, various influences within the oxygen transport system might disturb the determinations. There are not only detraining effects but also well-known other influences, such as blood- and fluid shifts induced by weightlessness. They might have an impact on the circulatory system. Some of these factors have been simulated by immersion, blood donation, and changing of the body position.

  2. Modelling cycle to cycle variations in an SI engine with detailed chemical kinetics

    SciTech Connect

    Etheridge, Jonathan; Mosbach, Sebastian; Kraft, Markus; Wu, Hao; Collings, Nick

    2011-01-15

    This paper presents experimental results and a new computational model that investigate cycle to cycle variations (CCV) in a spark ignition (SI) engine. An established stochastic reactor model (SRM) previously used to examine homogeneous charge compression ignition (HCCI) combustion has been extended by spark initiation, flame propagation and flame termination sub-models in order to simulate combustion in SI engines. The model contains a detailed chemical mechanism but relatively short computation times are achieved. The flame front is assumed to be spherical and centred at the spark location, and a pent roof and piston bowl geometry are accounted for. The model is validated by simulating the pressure profile and emissions from an iso-octane fuelled single cylinder research engine that showed low CCV. The effects of key parameters are investigated. Experimental results that show cycle to cycle fluctuations in a four-cylinder naturally aspirated gasoline fuelled SI engine are presented. The model is then coupled with GT-Power, a one-dimensional engine simulation tool, which is used to simulate the breathing events during a multi-cycle simulation. This allows an investigation of the cyclic fluctuations in peak pressure. The source and magnitude of nitric oxide (NO) emissions produced by different cycles are then investigated. It was found that faster burning cycles result in increased NO emissions compared with cycles that have a slower rate of combustion and that more is produced in the early stages of combustion compared with later in the cycle. The majority of NO was produced via the thermal mechanism just after combustion begins. (author)

  3. A two-parameter kinetic model based on a time-dependent activity coefficient accurately describes enzymatic cellulose digestion

    PubMed Central

    Kostylev, Maxim; Wilson, David

    2014-01-01

    Lignocellulosic biomass is a potential source of renewable, low-carbon-footprint liquid fuels. Biomass recalcitrance and enzyme cost are key challenges associated with the large-scale production of cellulosic fuel. Kinetic modeling of enzymatic cellulose digestion has been complicated by the heterogeneous nature of the substrate and by the fact that a true steady state cannot be attained. We present a two-parameter kinetic model based on the Michaelis-Menten scheme (Michaelis L and Menten ML. (1913) Biochem Z 49:333–369), but with a time-dependent activity coefficient analogous to fractal-like kinetics formulated by Kopelman (Kopelman R. (1988) Science 241:1620–1626). We provide a mathematical derivation and experimental support to show that one of the parameters is a total activity coefficient and the other is an intrinsic constant that reflects the ability of the cellulases to overcome substrate recalcitrance. The model is applicable to individual cellulases and their mixtures at low-to-medium enzyme loads. Using biomass degrading enzymes from a cellulolytic bacterium Thermobifida fusca we show that the model can be used for mechanistic studies of enzymatic cellulose digestion. We also demonstrate that it applies to the crude supernatant of the widely studied cellulolytic fungus Trichoderma reesei and can thus be used to compare cellulases from different organisms. The two parameters may serve a similar role to Vmax, KM, and kcat in classical kinetics. A similar approach may be applicable to other enzymes with heterogeneous substrates and where a steady state is not achievable. PMID:23837567

  4. Variations of the ionospheric parameters obtained from ground based measurements of ULF magnetic noise

    NASA Astrophysics Data System (ADS)

    Ermakova, Elena; Kotik, Dmitry; Bösinger, Tilmann

    2016-07-01

    The dynamics of the amplitude spectra and polarization parameter (epsilon)[1] of magnetic ULF noise were investigated during different seasons and high geomagnetic activity time using the data on the horizontal magnetic components monitoring at mid-latitude (New Life, Russia, 56 N, 46 E) and low-latitude stations (Crete, 35.15 N, 25.20 E). It was found that abrupt changes in the spectral polarization parameters can be linked as with variation of height of maximum and the electron density of the F-layer, and with a change in ionospheric parameters profiles at lower altitudes, for example, with the appearance of sporadic Es-layers and intermediate layers, located between the E and F-layers. It was detected the peculiarities in the daily dynamics of the epsilon parameter at low latitudes: a) the appearance in some cases more complicated than in the mid-latitudes, epsilon structure of the spectrum associated with the presence of two different values of the boundary frequency fB [2]; b) a decreasing of fB near local midnight observed in 70% of cases; c) observation of typical for dark time epsilon spectra after sunrise in the winter season. The numerical calculations of epsilon parameter were made using the IRI-2012 model with setting the models of sporadic and intermediate layers. The results revealed the dependence of the polarization spectra of the intensity and height of such thin layers. The specific changes in the electron density at altitudes of 80-350 km during the recovery phase of strong magnetic storms were defined basing on a comparative analysis of the experimental spectra and the results of the numerical calculations. References. 1. E. N. Ermakova, D. S. Kotik, A. V.Ryabov, A. V.Pershin, T. B.osinger, and Q. Zhou, Studying the variation of the broadband spectral maximum parameters in the natural ULF fields, Radiophysics and Quantum Electronics, Vol. 55, No. 10-11, March, 2013 p. 605-615. 2. T. Bosinger, A. G. Demekhov, E. N. Ermakova, C. Haldoupis and Q

  5. Covariations between Shell-Growth Parameters and the Control of the Ranges of Variation of Functionally Relevant Shell-Shape Parameters in Bivalves: A Theoretical Approach

    PubMed Central

    Béguinot, Jean

    2014-01-01

    Major traits of shell shape in bivalves may alternatively be described in terms of (i) functionally relevant parameters, assumed to play a significant role in the adaptation of bivalves molluscs to their environments (such as the shell-outline elongation E, ventral convexity K, and dissymmetry D), or (ii) growth-based parameters, directly controlled by the animal. Due to the geometrical linkage between functionally-relevant and growth-based parameters, adaptive constraints that may either widen or narrow the respective ranges of variations of the functional parameters lead to the onset of specific covariations (either positive or negative) between the growth-based parameters. This has practical interest since adaptive constraints are often difficult to identify directly, while they can be conveniently inferred indirectly via the easily recorded patterns of covariances between growth-based parameters. Hereafter, I provide the theoretical background of this tool, including (1) establishing the geometrical relationships between growth-based and functionally relevant parameters and (2) then specifying the correspondences between the different patterns of adaptive constraints, widening or narrowing the variations of the functional parameters and the corresponding patterns of covariations between the growth-based parameters. Illustrative examples of the practical use of this tool are provided, considering both interspecific and intraspecific variations within marine and fresh-water clams.

  6. Detecting spatial variations of erythrocytes by ultrasound backscattering statistical parameters under pulsatile flow.

    PubMed

    Huang, Chih-Chung

    2011-05-01

    The echogenicity of whole blood is known to vary during the flow cycle under pulsatile flow both in vitro and in vivo. However, the fundamental underlying mechanisms remain uncertain. The combined effects of flow acceleration and the shear rate were recently used to explain the cyclic variations of signals backscattered from flowing blood. However, testing this hypothesis requires determination of the spatial distributions of red blood cells (RBCs) in flowing blood. Recently, the Nakagami (m) and scaling (Ω) parameters have been used, respectively, to detect the spatial distributions of RBCs and the intensity of backscattering signal from blood under steady flow. For a better understanding of the relationship between the spatial distributions of RBCs and erythrocyte aggregation under pulsatile flow condition, these ultrasound backscattering statistical parameters were used, in this study, to characterize signals backscattered from both whole blood and RBC suspensions at different peak flow velocities (from 10 to 30 cm/s) and hematocrits (20% and 40%). The experiments were carried out by a 35-MHz ultrasound transducer. The m and Ω parameters were calculated for different blood properties and conditions, and the flow velocity in the center of blood flowing through a tube was measured synchronously. In whole blood, the results demonstrated that most RBCs were aggregated progressively toward the center of tube as the flow velocity started to accelerate, and that the increase in the intensity of the backscattered signal envelope to a maximum was attributable to larger rouleaux being formed in the center of tube. This phenomenon became apparent at a lower peak flow velocity with 40% hematocrit. However, there were no cyclic and spatial variations of the backscattering signal over a pulsatile cycle in RBC suspensions. PMID:21134805

  7. Spatial and Temporal Variation of Physico-chemical Parameters in the Merbok Estuary, Kedah, Malaysia

    PubMed Central

    Fatema, Kaniz; Wan Maznah, WO; Isa, Mansor Mat

    2014-01-01

    In this study, factor analysis (FA) was applied to extract the hidden factors responsible for water quality variations during both wet and dry seasons. Water samples were collected from six sampling stations (St. 1 Lalang River, St. 2 Semeling River, St. 3 Jagung River, St. 4 Teluk Wang River, St. 5 Gelam River and St. 6 Derhaka River) in the Merbok estuary, Malaysia from January to December 2011; the samples were further analysed in the laboratory. Correlation analysis of the data sets showed strong correlations between the parameters. Nutrients such as nitrate (NO3−), nitrite (NO2−), ammonia (NH3) and phosphate (PO43−) were determined to be critical indicators of water quality throughout the year. Influential water quality parameters during the wet season were conductivity, salinity, biochemical oxygen demand (BOD), dissolved oxygen (DO) and chlorophyll a (Chla), whereas total suspended solid (TSS) and pH were critical water quality indicators during the dry season. The Kruskal-Wallis H test showed that water quality parameters were significantly different among the sampling months and stations (p<0.05), and Mann-Whitney U tests further revealed that the significantly different parameters were temperature, pH, DO, TSS, NO2− and BOD (p<0.01), whereas salinity, conductivity, NO3−, PO43−, NH3 and Chla were not significantly different (p>0.05). Water quality parameters in the estuary varied on both temporal and spatial scales and these results may serve as baseline information for estuary management, specifically for the Merbok estuary. PMID:27073596

  8. Spatial and Temporal Variation of Physico-chemical Parameters in the Merbok Estuary, Kedah, Malaysia.

    PubMed

    Fatema, Kaniz; Wan Maznah, W O; Isa, Mansor Mat

    2014-12-01

    In this study, factor analysis (FA) was applied to extract the hidden factors responsible for water quality variations during both wet and dry seasons. Water samples were collected from six sampling stations (St. 1 Lalang River, St. 2 Semeling River, St. 3 Jagung River, St. 4 Teluk Wang River, St. 5 Gelam River and St. 6 Derhaka River) in the Merbok estuary, Malaysia from January to December 2011; the samples were further analysed in the laboratory. Correlation analysis of the data sets showed strong correlations between the parameters. Nutrients such as nitrate (NO3 (-)), nitrite (NO2 (-)), ammonia (NH3) and phosphate (PO4 (3-)) were determined to be critical indicators of water quality throughout the year. Influential water quality parameters during the wet season were conductivity, salinity, biochemical oxygen demand (BOD), dissolved oxygen (DO) and chlorophyll a (Chla), whereas total suspended solid (TSS) and pH were critical water quality indicators during the dry season. The Kruskal-Wallis H test showed that water quality parameters were significantly different among the sampling months and stations (p<0.05), and Mann-Whitney U tests further revealed that the significantly different parameters were temperature, pH, DO, TSS, NO2 (-) and BOD (p<0.01), whereas salinity, conductivity, NO3 (-), PO4 (3-), NH3 and Chla were not significantly different (p>0.05). Water quality parameters in the estuary varied on both temporal and spatial scales and these results may serve as baseline information for estuary management, specifically for the Merbok estuary. PMID:27073596

  9. Intrinsic kinetic parameters of Thermococcus onnurineus NA1 strains and prediction of optimum carbon monoxide level for ideal bioreactor operation.

    PubMed

    Jeong, Yeseul; Jang, Nulee; Yasin, Muhammad; Park, Shinyoung; Chang, In Seop

    2016-02-01

    This study determines and compares the intrinsic kinetic parameters (Ks and Ki) of selected Thermococcus onnurineus NA1 strains (wild-type (WT), and mutants MC01, MC02, and WTC156T) using the substrate inhibition model. Ks and Ki values were used to find the optimum dissolved CO (CL) conditions inside the reactor. The results showed that in terms of the maximum specific CO consumption rates (qCO(max)) of WT, MC01, MC02, and WTC156T the optimum activities can be achieved by maintaining the CL levels at 0.56mM, 0.52mM, 0.58mM, and 0.75mM, respectively. The qCO(max) value of WTC156T at 0.75mM was found to be 1.5-fold higher than for the WT strain, confirming its superiority. Kinetic modeling was then used to predict the conditions required to maintain the optimum CL levels and high cell concentrations in the reactor, based on the kinetic parameters of the WTC156T strain. PMID:26638136

  10. Colocalization Estimation Using Graphical Modeling and Variational Bayesian Expectation Maximization: Towards a Parameter-Free Approach.

    PubMed

    Awate, Suyash P; Radhakrishnan, Thyagarajan

    2015-01-01

    In microscopy imaging, colocalization between two biological entities (e.g., protein-protein or protein-cell) refers to the (stochastic) dependencies between the spatial locations of the two entities in the biological specimen. Measuring colocalization between two entities relies on fluorescence imaging of the specimen using two fluorescent chemicals, each of which indicates the presence/absence of one of the entities at any pixel location. State-of-the-art methods for estimating colocalization rely on post-processing image data using an adhoc sequence of algorithms with many free parameters that are tuned visually. This leads to loss of reproducibility of the results. This paper proposes a brand-new framework for estimating the nature and strength of colocalization directly from corrupted image data by solving a single unified optimization problem that automatically deals with noise, object labeling, and parameter tuning. The proposed framework relies on probabilistic graphical image modeling and a novel inference scheme using variational Bayesian expectation maximization for estimating all model parameters, including colocalization, from data. Results on simulated and real-world data demonstrate improved performance over the state of the art. PMID:26221663

  11. Variations of immune parameters in terrestrial isopods: a matter of gender, aging and Wolbachia.

    PubMed

    Sicard, Mathieu; Chevalier, Frédéric; De Vlechouver, Mickaël; Bouchon, Didier; Grève, Pierre; Braquart-Varnier, Christine

    2010-09-01

    Ecological factors modulate animal immunocompetence and potentially shape the evolution of their immune systems. Not only environmental parameters impact on immunocompetence: Aging is one major cause of variability of immunocompetence between individuals, and sex-specific levels of immunocompetence have also been frequently described. Moreover, a growing core of data put in light that vertically transmitted symbionts can dramatically modulate the immunocompetence of their hosts. In this study, we addressed the influence of gender, age and the feminising endosymbiont Wolbachia (wVulC) on variations in haemocyte density, total PO activity and bacterial load in the haemolymph of the terrestrial isopod Armadillidium vulgare. This host-symbiont system is of particular interest to address this question since: (1) wVulC was previously shown as immunosuppressive in middle-aged females and (2) wVulC influences sex determination. We show that age, gender and Wolbachia modulate together immune parameters in A. vulgare. However, wVulC, which interacts with aging, appears to be the prominent factor interfering with both PO activity and haemocyte density. This interference with immune parameters is not the only aspect of wVulC virulence on its host, as reproduction and survival are also altered. PMID:20676599

  12. Variations of immune parameters in terrestrial isopods: a matter of gender, aging and Wolbachia

    NASA Astrophysics Data System (ADS)

    Sicard, Mathieu; Chevalier, Frédéric; de Vlechouver, Mickaël; Bouchon, Didier; Grève, Pierre; Braquart-Varnier, Christine

    2010-09-01

    Ecological factors modulate animal immunocompetence and potentially shape the evolution of their immune systems. Not only environmental parameters impact on immunocompetence: Aging is one major cause of variability of immunocompetence between individuals, and sex-specific levels of immunocompetence have also been frequently described. Moreover, a growing core of data put in light that vertically transmitted symbionts can dramatically modulate the immunocompetence of their hosts. In this study, we addressed the influence of gender, age and the feminising endosymbiont Wolbachia ( wVulC) on variations in haemocyte density, total PO activity and bacterial load in the haemolymph of the terrestrial isopod Armadillidium vulgare. This host-symbiont system is of particular interest to address this question since: (1) wVulC was previously shown as immunosuppressive in middle-aged females and (2) wVulC influences sex determination. We show that age, gender and Wolbachia modulate together immune parameters in A. vulgare. However, wVulC, which interacts with aging, appears to be the prominent factor interfering with both PO activity and haemocyte density. This interference with immune parameters is not the only aspect of wVulC virulence on its host, as reproduction and survival are also altered.

  13. Reaction kinetic parameters for ion transport from steady-state current-voltage curves.

    PubMed Central

    Gradmann, D; Klieber, H G; Hansen, U P

    1987-01-01

    This study demonstrates possible ways to estimate the rate constants of reaction kinetic models for ion transport from steady-state current-voltage data as measured at various substrate concentrations. This issue is treated theoretically by algebraic reduction and extension of a reaction kinetic four-state model for uniport. Furthermore, an example for application is given; current-voltage data from an open K+ selective channel (Schroeder, J.I., R. Hedrich, and J.M. Fernandez, 1984, Nature (Lond.), 312:361-362) supplemented by some new data have been evaluated. The analysis yields absolute numerical estimates of the 14 rate constants of a six-state model, which is discussed in a wider context. PMID:2437973

  14. Open channel noise. VI. Analysis of amplitude histograms to determine rapid kinetic parameters.

    PubMed Central

    Heinemann, S H; Sigworth, F J

    1991-01-01

    Recently we reported that rapid fluctuations of ion currents flowing through open gramicidin A channels exceed the expected level of pure transport noise at low ion concentrations (Heinemann, S. H. and F. J. Sigworth. 1990. Biophys. J. 57:499-514). Based on comparisons with kinetic ion transport models we concluded that this excess noise is likely caused by current interruptions lasting approximately 1 microsecond. Here we introduce a method using the higher-order cumulants of the amplitude distribution to estimate the kinetics of channel closing events far below the actual time resolution of the recording system. Using this method on data recorded with 10 kHz bandwidth, estimates for gap time constants on the order of 1 microsecond were obtained, similar to the earlier predictions. PMID:1718467

  15. Relevance of thermodynamic and kinetic parameters of chemical vapor deposition precursors.

    PubMed

    Selvakumar, J; Nagaraja, K S; Sathiyamoorthy, D

    2011-09-01

    We have studied various metallorganic and organometallic compounds by simultaneous nonisothermal thermogravimetric and differential thermogravimetric analyses to confirm their volatility and thermal stability. The equilibrium vapor pressures of the metallorganic and organometallic compounds were determined by horizontal dual arm single furnace thermoanalyzer as transpiration apparatus. Antoine coefficients were calculated from the temperature dependence equilibrium vapor pressure data. The model-fitting solid-state kinetic analyses of Al(acac)3, (acac = acetylacetonato), Cr(CO)6, Fe(Cp)2, (Cp-cyclopentadienyl), Ga(acac)3, Mn(tmhd)3, and Y(tmhd)3 (tmhd = 2,2,6,6,-tetramethyl-3,5-heptanedionato) revealed that the processes follow diffusion controlled, contracting area and zero order model sublimation or evaporation kinetics. The activation energy for the sublimation/evaporation processes were calculated by model-free kinetic methods. Thin films of nickel and lanthanum-strontium-manganite (LSM) are grown on silicon substrate at 573 K using selected metallorganic complexes of Ni[(acac)2en], La(tmhd)3, Sr(tmhd)2 and Mn(tmhd)3 as precursors by plasma assisted liquid injection chemical vapor deposition (PA-LICVD). The deposited films were characterized by scanning electron microscopy and energy dispersive X-ray analysis for their composition and morphology. PMID:22097553

  16. A variational approach for dissipative quantum transport in a wide parameter space

    SciTech Connect

    Zhang, Yu Kwok, YanHo; Chen, GuanHua; Yam, ChiYung

    2015-09-14

    Recent development of theoretical method for dissipative quantum transport has achieved notable progresses in the weak or strong electron-phonon coupling regime. However, a generalized theory for dissipative quantum transport in a wide parameter space had not been established. In this work, a variational polaron theory for dissipative quantum transport in a wide range of electron-phonon coupling is developed. The optimal polaron transformation is determined by the optimization of the Feynman-Bogoliubov upper bound of free energy. The free energy minimization ends up with an optimal mean-field Hamiltonian and a minimal interaction Hamiltonian. Hence, second-order perturbation can be applied to the transformed system, resulting in an accurate and efficient method for the treatment of dissipative quantum transport with different electron-phonon coupling strength. Numerical benchmark calculation on a single site model coupled to one phonon mode is presented.

  17. A variational approach for dissipative quantum transport in a wide parameter space

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Yam, ChiYung; Kwok, YanHo; Chen, GuanHua

    2015-09-01

    Recent development of theoretical method for dissipative quantum transport has achieved notable progresses in the weak or strong electron-phonon coupling regime. However, a generalized theory for dissipative quantum transport in a wide parameter space had not been established. In this work, a variational polaron theory for dissipative quantum transport in a wide range of electron-phonon coupling is developed. The optimal polaron transformation is determined by the optimization of the Feynman-Bogoliubov upper bound of free energy. The free energy minimization ends up with an optimal mean-field Hamiltonian and a minimal interaction Hamiltonian. Hence, second-order perturbation can be applied to the transformed system, resulting in an accurate and efficient method for the treatment of dissipative quantum transport with different electron-phonon coupling strength. Numerical benchmark calculation on a single site model coupled to one phonon mode is presented.

  18. Effect of emitter parameter variation on the performance of heteroepitaxial indium phosphide solar cells

    NASA Technical Reports Server (NTRS)

    Jain, R. K.; Flood, D. J.

    1990-01-01

    Metalorganic chemical-vapor-deposited heteroepitaxial indium phosphide (InP) solar cell experimental results were simulated by using a PC-1D computer model. The effect of emitter parameter variation on the performance of n(+)/p/p(+) heteroepitaxial InP/GaAs solar cell was presented. The thinner and lighter doped emitters were observed to offer higher cell efficiencies. The influence of emitter thickness and minority carrier diffusion length on the cell efficiency with respect to dislocation density was studied. Heteroepitaxial cells with efficiencies similar to present day homojunction InP efficiencies (greaater than 16 percent AM0) were shown to be attainable if a dislocation density lower than 10(exp 6)/sq cm could be achieved. A realistic optimized design study yielded InP solar cells of over 22 percent AM0 efficiency at 25 C.

  19. Effect of emitter parameter variation on the performance of heteroepitaxial indium phosphide solar cells

    NASA Technical Reports Server (NTRS)

    Jain, Raj K.; Flood, Dennis J.

    1990-01-01

    Metallorganic chemical-vapor-deposited heteroepitaxial indium phosphide (InP) solar cell experimental results were simulated by using a PC-1D computer model. The effect of emitter parameter variation on the performance of n(+)/p/p(+) heteroepitaxial InP/GaAs solar cell was presented. The thinner and lighter doped emitters were observed to offer higher cell efficiencies. The influence of emitter thickness and minority carrier diffusion length on the cell efficiency with respect to dislocation density was studied. Heteroepitaxial cells with efficiencies similar to present day homojunction InP efficiencies (greater than 16 percent AMO) were shown to be attainable if a dislocation density lower than 10(exp 6)/sq cm could be achieved. A realistic optimized design study yielded InP solar cells of over 22 percent AMO efficiency at 25 C.

  20. Photodegradation of naproxen in water under simulated solar radiation: mechanism, kinetics, and toxicity variation.

    PubMed

    Ma, Dujuan; Liu, Guoguang; Lv, Wenying; Yao, Kun; Zhang, Xiangdan; Xiao, Huahua

    2014-01-01

    The main objective of this study was to investigate the degradation mechanism, the reaction kinetics, and the evolution of toxicity of naproxen in waters under simulated solar radiation. These criteria were investigated by conducting quenching experiments with reactive oxygen species (ROS), oxygen concentration experiments, and toxicity evaluations with Vibrio fischeri bacteria. The results indicated that the degradation of naproxen proceeds via pseudo first-order kinetics in all cases and that photodegradation included degradation by direct photolysis and by self-sensitization via ROS; the contribution rates of self-sensitized photodegradation were 1.4%, 65.8%, and 31.7% via ·OH, (1)O₂ and O₂(•-), respectively. Furthermore, the oxygen concentration experiments indicated that dissolved oxygen inhibited the direct photodegradation of naproxen, and the higher the oxygen content, the more pronounced the inhibitory effect. The toxicity evaluation illustrated that some of the intermediate products formed were more toxic than naproxen. PMID:24638836

  1. Optimization of residual stresses in MMC's through the variation of interfacial layer architectures and processing parameters

    NASA Technical Reports Server (NTRS)

    Pindera, Marek-Jerzy; Salzar, Robert S.

    1996-01-01

    The objective of this work was the development of efficient, user-friendly computer codes for optimizing fabrication-induced residual stresses in metal matrix composites through the use of homogeneous and heterogeneous interfacial layer architectures and processing parameter variation. To satisfy this objective, three major computer codes have been developed and delivered to the NASA-Lewis Research Center, namely MCCM, OPTCOMP, and OPTCOMP2. MCCM is a general research-oriented code for investigating the effects of microstructural details, such as layered morphology of SCS-6 SiC fibers and multiple homogeneous interfacial layers, on the inelastic response of unidirectional metal matrix composites under axisymmetric thermomechanical loading. OPTCOMP and OPTCOMP2 combine the major analysis module resident in MCCM with a commercially-available optimization algorithm and are driven by user-friendly interfaces which facilitate input data construction and program execution. OPTCOMP enables the user to identify those dimensions, geometric arrangements and thermoelastoplastic properties of homogeneous interfacial layers that minimize thermal residual stresses for the specified set of constraints. OPTCOMP2 provides additional flexibility in the residual stress optimization through variation of the processing parameters (time, temperature, external pressure and axial load) as well as the microstructure of the interfacial region which is treated as a heterogeneous two-phase composite. Overviews of the capabilities of these codes are provided together with a summary of results that addresses the effects of various microstructural details of the fiber, interfacial layers and matrix region on the optimization of fabrication-induced residual stresses in metal matrix composites.

  2. Effects of Spectral and Temporal Variations in Gamma Ray Burst Parameters

    NASA Astrophysics Data System (ADS)

    Ejzak, L. M.; Melott, A. L.; Thomas, B. C.; Medvedev, M. V.

    2005-12-01

    It has previously been shown that a typical gamma ray burst could have significant effects on the Earth, including such considerations as ozone depletion and production of odd nitrogen compounds. These effects in turn contribute to processes such as DNA damage in organisms, increasing opacity of the atmosphere, and nitric acid rain. Our interest lies in the role that these processes may play in mass extinction events, in particular the Ordovician mass extinction 443 Mya. Here we investigate variations in certain burst parameters and the resulting variation in the severity of effect that the burst radiation has on the Earth's atmosphere. We extend the range of photon energies used in the model beyond the range used in previous studies, and model bursts with a number of different peak energies. We also alter the temporal profile of the radiation during the burst itself. This research is conducted with support from NASA's Astrobiology: Exobiology and Evolutionary Biology Program and in collaboration with NASA's Goddard Space Flight Center, and with supercomputer support from NCSA.

  3. A comparison of region-based and pixel-based CEUS kinetics parameters in the assessment of arthritis

    NASA Astrophysics Data System (ADS)

    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.

  4. Applicability of fluorescence-based sensors to the determination of kinetic parameters for O2 in oxygenases

    PubMed Central

    Di Russo, Natali V.; Bruner, Steven D.; Roitberg, Adrian E.

    2015-01-01

    Optical methods for O2 determination based on dynamic fluorescence quenching have been applied to measure oxygen uptake rates in cell culture, and to determine intracellular oxygen levels. Here we demonstrate the applicability of fluorescence-based probes in determining kinetic parameters for O2 using as an example catalysis by a cofactor-independent oxygenase (DpgC). Fluorescence-based sensors provide a direct assessment of enzyme-catalyzed O2 consumption using commercially available, low-cost instrumentation that is easily customizable and thus constitute a convenient alternative to the widely-used Clark-type electrode, especially in cases where chemical interference is expected to be problematic. PMID:25637681

  5. Material properties of evolutionary diverse spider silks described by variation in a single structural parameter.

    PubMed

    Madurga, Rodrigo; Plaza, Gustavo R; Blackledge, Todd A; Guinea, Gustavo V; Elices, Manuel; Pérez-Rigueiro, José

    2016-01-01

    Spider major ampullate gland silks (MAS) vary greatly in material properties among species but, this variation is shown here to be confined to evolutionary shifts along a single universal performance trajectory. This reveals an underlying design principle that is maintained across large changes in both spider ecology and silk chemistry. Persistence of this design principle becomes apparent after the material properties are defined relative to the true alignment parameter, which describes the orientation and stretching of the protein chains in the silk fiber. Our results show that the mechanical behavior of all Entelegynae major ampullate silk fibers, under any conditions, are described by this single parameter that connects the sequential action of three deformation micromechanisms during stretching: stressing of protein-protein hydrogen bonds, rotation of the β-nanocrystals and growth of the ordered fraction. Conservation of these traits for over 230 million years is an indication of the optimal design of the material and gives valuable clues for the production of biomimetic counterparts based on major ampullate spider silk. PMID:26755434

  6. Spatial Variation of the Relationship between PM2.5 Concentrations and Meteorological Parameters in China

    PubMed Central

    Lin, Gang; Fu, Jingying; Jiang, Dong; Wang, Jianhua; Wang, Qiao; Dong, Donglin

    2015-01-01

    Epidemiological studies around the world have reported that fine particulate matter (PM2.5) is closely associated with human health. The distribution of PM2.5 concentrations is influenced by multiple geographic and socioeconomic factors. Using a remote-sensing-derived PM2.5 dataset, this paper explores the relationship between PM2.5 concentrations and meteorological parameters and their spatial variance in China for the period 2001–2010. The spatial variations of the relationships between the annual average PM2.5, the annual average precipitation (AAP), and the annual average temperature (AAT) were evaluated using the Geographically Weighted Regression (GWR) model. The results indicated that PM2.5 had a strong and stable correlation with meteorological parameters. In particular, PM2.5 had a negative correlation with precipitation and a positive correlation with temperature. In addition, the relationship between the variables changed over space, and the strong negative correlation between PM2.5 and the AAP mainly appeared in the warm temperate semihumid region and northern subtropical humid region in 2001 and 2010, with some localized differences. The strong positive correlation between the PM2.5 and the AAT mainly occurred in the mid-temperate semiarid region, the humid, semihumid, and semiarid warm temperate regions, and the northern subtropical humid region in 2001 and 2010. PMID:26295046

  7. Effects of rotor parameter variations on handling qualities of unaugmented helicopters in simulated terrain flight

    NASA Technical Reports Server (NTRS)

    Talbot, P. D.; Dugan, D. D.; Chen, R. T. N.; Gerdes, R. M.

    1980-01-01

    A coordinated analysis and ground simulator experiment was performed to investigate the effects on single rotor helicopter handling qualities of systematic variations in the main rotor hinge restraint, hub hinge offset, pitch-flap coupling, and blade lock number. Teetering rotor, articulated rotor, and hingeless rotor helicopters were evaluated by research pilots in special low level flying tasks involving obstacle avoidance at 60 to 100 knots airspeed. The results of the experiment are in the form of pilot ratings, pilot commentary, and some objective performance measures. Criteria for damping and sensitivity are reexamined when combined with the additional factors of cross coupling due to pitch and roll rates, pitch coupling with collective pitch, and longitudinal static stability. Ratings obtained with and without motion are compared. Acceptable flying qualities were obtained within each rotor type by suitable adjustment of the hub parameters, however, pure teetering rotors were found to lack control power for the tasks. A limit for the coupling parameter L sub q/L sub p of 0.35 is suggested.

  8. Material properties of evolutionary diverse spider silks described by variation in a single structural parameter

    PubMed Central

    Madurga, Rodrigo; Plaza, Gustavo R.; Blackledge, Todd A.; Guinea, Gustavo.V.; Elices, Manuel; Pérez-Rigueiro, José

    2016-01-01

    Spider major ampullate gland silks (MAS) vary greatly in material properties among species but, this variation is shown here to be confined to evolutionary shifts along a single universal performance trajectory. This reveals an underlying design principle that is maintained across large changes in both spider ecology and silk chemistry. Persistence of this design principle becomes apparent after the material properties are defined relative to the true alignment parameter, which describes the orientation and stretching of the protein chains in the silk fiber. Our results show that the mechanical behavior of all Entelegynae major ampullate silk fibers, under any conditions, are described by this single parameter that connects the sequential action of three deformation micromechanisms during stretching: stressing of protein-protein hydrogen bonds, rotation of the β-nanocrystals and growth of the ordered fraction. Conservation of these traits for over 230 million years is an indication of the optimal design of the material and gives valuable clues for the production of biomimetic counterparts based on major ampullate spider silk. PMID:26755434

  9. Seasonal variation of selected performance parameters in épée fencers.

    PubMed Central

    Koutedakis, Y; Ridgeon, A; Sharp, N C; Boreham, C

    1993-01-01

    In this study, anthropometric measurements were carried out on seven British international male épée fencers, using a maximal treadmill running test, a 20-s Wingate-type test, and isokinetic dynamometry. Testing was conducted on two occasions, 5 to 6 months apart, during mid-off-season (preparation) and mid-in-season (competition) periods. Maximal oxygen intake (VO2max) and maximal respiratory exchange ratio (Rmax) were among the parameters obtained from the treadmill test, while peak and mean anaerobic power outputs were measured during a 20-s maximal effort. Knee extensor and flexor muscle forces from both dominant (leading) and non-dominant (trailing) legs were assessed at 1.04, 3.14 and 4.19 rad sec-1. Statistical analyses revealed lower mean VO2max (P < 0.05) and mean Rmax values (P < 0.02) at the in-season assessments compared with off-season. In-season testing also demonstrated significantly lower peak torques for both dominant and non-dominant knee extensors compared with off-season assessments at all velocities (P < 0.05 to P < 0.004). Furthermore, in-season peak torque for the non-dominant leg flexors was lower (P < 0.03) at 4.19 rad sec-1 than off-season. We conclude that current training practices may account for the observed seasonal variations in performance related physiological parameters in fencers. PMID:8242273

  10. Material properties of evolutionary diverse spider silks described by variation in a single structural parameter

    NASA Astrophysics Data System (ADS)

    Madurga, Rodrigo; Plaza, Gustavo R.; Blackledge, Todd A.; Guinea, Gustavo. V.; Elices, Manuel; Pérez-Rigueiro, José

    2016-01-01

    Spider major ampullate gland silks (MAS) vary greatly in material properties among species but, this variation is shown here to be confined to evolutionary shifts along a single universal performance trajectory. This reveals an underlying design principle that is maintained across large changes in both spider ecology and silk chemistry. Persistence of this design principle becomes apparent after the material properties are defined relative to the true alignment parameter, which describes the orientation and stretching of the protein chains in the silk fiber. Our results show that the mechanical behavior of all Entelegynae major ampullate silk fibers, under any conditions, are described by this single parameter that connects the sequential action of three deformation micromechanisms during stretching: stressing of protein-protein hydrogen bonds, rotation of the β-nanocrystals and growth of the ordered fraction. Conservation of these traits for over 230 million years is an indication of the optimal design of the material and gives valuable clues for the production of biomimetic counterparts based on major ampullate spider silk.

  11. Parameter study and optimization for piezoelectric energy harvester for TPMS considering speed variation

    NASA Astrophysics Data System (ADS)

    Toghi Eshghi, Amin; Lee, Soobum; Lee, Hanmin; Kim, Young-Cheol

    2016-04-01

    In this paper, we perform design parameter study and design optimization for a piezoelectric energy harvester considering vehicle speed variation. Initially, a FEM model using ANSYS is developed to appraise the performance of a piezoelectric harvester in a rotating tire. The energy harvester proposed here uses the vertical deformation at contact patch area from the car weight and centrifugal acceleration. This harvester is composed of a beam which is clamped at both ends and a piezoelectric material is attached on the top of that. The piezoelectric material possesses the 31 mode of transduction in which the direction of applied field is perpendicular to that of the electric field. To optimize the harvester performance, we would change the geometrical parameters of the harvester to obtain the maximum power. One of the main challenges in the design process is obtaining the required power while considering the constraints for harvester weight and volume. These two concerns are addressed in this paper. Since the final goal of this study is the development of an energy harvester with a wireless sensor system installed in a real car, the real time data for varied velocity of a vehicle are taken into account for power measurements. This study concludes that the proposed design is applicable to wireless tire sensor systems.

  12. Spatial Variation of the Relationship between PM 2.5 Concentrations and Meteorological Parameters in China.

    PubMed

    Lin, Gang; Fu, Jingying; Jiang, Dong; Wang, Jianhua; Wang, Qiao; Dong, Donglin

    2015-01-01

    Epidemiological studies around the world have reported that fine particulate matter (PM2.5) is closely associated with human health. The distribution of PM2.5 concentrations is influenced by multiple geographic and socioeconomic factors. Using a remote-sensing-derived PM2.5 dataset, this paper explores the relationship between PM2.5 concentrations and meteorological parameters and their spatial variance in China for the period 2001-2010. The spatial variations of the relationships between the annual average PM2.5, the annual average precipitation (AAP), and the annual average temperature (AAT) were evaluated using the Geographically Weighted Regression (GWR) model. The results indicated that PM2.5 had a strong and stable correlation with meteorological parameters. In particular, PM2.5 had a negative correlation with precipitation and a positive correlation with temperature. In addition, the relationship between the variables changed over space, and the strong negative correlation between PM2.5 and the AAP mainly appeared in the warm temperate semihumid region and northern subtropical humid region in 2001 and 2010, with some localized differences. The strong positive correlation between the PM2.5 and the AAT mainly occurred in the mid-temperate semiarid region, the humid, semihumid, and semiarid warm temperate regions, and the northern subtropical humid region in 2001 and 2010. PMID:26295046

  13. TOPICAL REVIEW: Kinetic phenomena in charged particle transport in gases, swarm parameters and cross section data

    NASA Astrophysics Data System (ADS)

    Petrovic, Z. Lj; Suvakov, M.; Nikitovic, Z.; Dujko, S.; Sasic, O.; Jovanovic, J.; Malovic, G.; Stojanovic, V.

    2007-02-01

    In this review we discuss the current status of the physics of charged particle swarms, mainly electrons. The whole field is analysed mainly through its relationship to plasma modelling and illustrated by some recent examples developed mainly by our group. The measurements of the swarm coefficients and the availability of the data are briefly discussed. More time is devoted to the development of complete electron molecule cross section sets along with recent examples such as NO, CF4 and HBr. We extend the discussion to the availability of ion and fast neutral data and how swarm experiments may serve to provide new data. As a point where new insight into the kinetics of charge particle transport is provided, the role of kinetic phenomena is discussed and recent examples are listed. We focus here on giving two examples on how non-conservative processes make dramatic effects in transport, the negative absolute mobility and the negative differential conductivity for positrons in argon. Finally we discuss the applicability of swarm data in plasma modelling and the relationship to other fields where swarm experiments and analysis make significant contributions. Based on the general invited lecture presented by the first author at ESCAMPIG 2006 at Lecce in Italy.

  14. Kinetic parameters of red pepper waste as biomass to solid biofuel.

    PubMed

    Maia, Amanda Alves Domingos; de Morais, Leandro Cardoso

    2016-03-01

    This work aimed to study the kinetic of thermal degradation of red pepper waste as solid biofuel to bioenergy production. The thermal degradation experiments were conducted at three heating rates, 5°C/min, 7.5°C/min and 10°C/min in a thermogravimetric analyzer and oxidative atmosphere. The kinetic analysis was carried out applying the isoconversional model of Ozawa-Flynn-Wall. The activation energy was considerate low and varied 29.49-147.25k J/mol. The enthalpies revealed the energy difference between the reagent and the activated complex agreed with activation energies, the values of the pre-exponential factor indicated empirical first order reactions, Gibbs free energy varied from 71.77 kJ/mol to 207.03 kJ/mol and the changes of entropies had negative values, indicating that the degree of disorder of products formed through bond dissociations was lower than initial reactants. The calorific value was 19.5 MJ/kg, considered a relevant result for bioenergy production. PMID:26773950

  15. On the optimal use of fictitious time in variation of parameters methods with application to BG14

    NASA Technical Reports Server (NTRS)

    Gottlieb, Robert G.

    1991-01-01

    The optimal way to use fictitious time in variation of parameter methods is presented. Setting fictitious time to zero at the end of each step is shown to cure the instability associated with some types of problems. Only some parameters are reinitialized, thereby retaining redundant information.

  16. Seasonal variation of hemato-biochemical parameters in indigenous pig: Zovawk of Mizoram

    PubMed Central

    Mayengbam, P.; Tolenkhomba, T. C.

    2015-01-01

    Aim: To investigate the influence of season on erythrocyte picture, plasma enzyme and electrolyte profile of local pig of Mizoram at a different age. Materials and Methods: A volume of 2 ml of blood samples were collected from 72 Zovawk pigs of three different age groups viz. pre-weaning, grower and adult pigs reared in College of Veterinary Sciences and Animal Husbandry Selesih, Aizawl, Mizoram, India, livestock farm during summer and winter in order to find out influence of season on erythrocyte picture, enzyme and electrolyte profile. The hematological parameters were estimated by using an automatic blood analyzer. The biochemical parameters were estimated by using diagnostic kits. Results: The grower pigs had lower hemoglobin (Hb), packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular Hb (MCH) during summer, rainy and winter seasons (p<0.05) and lower MCH concentration (MCHC) during summer season (p<0.05). Adult pigs had lower Hb with higher total erythrocyte count in rainy season. PCV and MCV of adult pigs decreased in summer (p<0.05). Serum glutamic oxaloacetic transaminase activity of both the grower and adult groups increased during summer and rainy seasons (p<0.05). Zovawk pigs had higher sodium (Na) and lower potassium (K) in rainy season (p<0.05). Pre-weaning piglets had higher Na, K, calcium (Ca), and magnesium (Mg) in summer than in winter. Grower pigs had higher Na, K and Ca in summer (p<0.05). Pi of pre-weaning and grower groups was higher in winter. Adult pigs had lower alkaline phosphatase activity and Ca in summer and higher Pi and Mg in winter (p<0.05). Conclusion: Seasonal variation in some hemato-biochemical parameters of Zovawk pig were investigated. Influence of season on the hemato-biochemical profile was most evident during the grower stage, followed by adults and pre-weaning piglets. PMID:27065639

  17. Variations in the elemental ratio of organic matter in the central Baltic Sea: Part II - Sensitivities of annual mass flux estimates to model parameter variations

    NASA Astrophysics Data System (ADS)

    Kreus, Markus; Schartau, Markus

    2015-06-01

    This study describes a sensitivity analysis that allows the parameters of a one-dimensional ecosystem model to be ranked according to their specificity in determining biochemical key fluxes. Key fluxes of interest are annual (a) total production (TP), (b) remineralization above the halocline (RM), and (c) export at 50 m (EX) at the Baltic Sea monitoring site BY15 located in the Gotland Deep basin. The model resolves mass flux of carbon (C), nitrogen (N), and phosphorous (P), while considering nitrogen fixation explicitly. Our first null hypothesis is that the variation of the value of every single model parameter affects each annual C, N, and P budget simultaneously. Our second null hypothesis states that the variation of every parameter value induces changes at least in either of the annual C, N or P budgets. Our analyses falsify both null hypotheses and reveal that 8 out of 36 parameters must be regarded redundant, as their variation neither alter annual key fluxes nor produce considerable time-shifts in model trajectories at the respective site. Seven parameters were found to induce substantial changes in annual C, N, and P flux estimates simultaneously. The assimilation efficiency of zooplankton turned out to be of vital importance. This parameter discriminates between the assimilation and destruction of algal prey during grazing. The fraction of unassimilated dead algal cells is critical for the amount of organic matter exported out of the euphotic zone. The maximum cellular N:C quota of diazotrophs and the degradation/hydrolysis rate of detrital carbon are two parameters that will likely remain unconstrained by time series data, but both affect the annual C budget considerably. Overall, our detailed specification of model sensitivities to parameter variations will facilitate the formulation of a well-posed inverse problem for the estimation of C, N and P fluxes from stock observations at the Gotland Deep.

  18. A physical parameter identification method of Lévy-driven vibratory systems based on multipower variation processes

    NASA Astrophysics Data System (ADS)

    Du, Xiu-Li; Lin, Jin-Guan; Liu, Guo-Xiang; Zhou, Xiu-Qing

    2015-05-01

    In this paper, we put forward a physical parameter identification method of Lévy-driven engineering structures. Based on the properties of the quadratic variation and multipower variation processes, the structural dynamic equation is decomposed into the Gaussian continuous-time autoregressive (CAR) equation and the pure jump-driven CAR equation. Both equations have the same unknown parameters as those included in the Lévy-driven system. The parameters of the Lévy-driven system are identified by the maximum likelihood estimation method of the Gaussian CAR system. The numerical results demonstrate that the method works well.

  19. Isotherm parameters and intraparticle mass transfer kinetics on molecularly imprinted polymers in acetonitrile/buffer mobile phases

    SciTech Connect

    Kim, Hyunjung; Kaczmarski, Krzysztof; Guiochon, Georges A

    2006-03-01

    The equilibrium isotherm and the intraparticle mass transfer kinetics of the enantiomers of the template were investigated on an Fmoc-L-tryptophan (Fmoc-L-Trp) imprinted polymer at different pHs and water concentrations in acetonitrile/aqueous buffer mobile phases. The equilibrium isotherm data were measured using frontal analysis at 25 {+-} 2 C. The adsorption energy distribution was found to be trimodal, with narrow modes. Consistent with this distribution, the adsorption data were modeled using a tri-Langmuir isotherm equation and the best estimates of the isotherm parameters were determined. The intraparticle mass transfer parameters were derived by comparing the profiles of experimental overloaded bands and the profiles calculated using the isotherm model and the lumped pore diffusion (POR) model of chromatography. These results showed that different adsorption and mass transfer mechanisms exist in mobile phases made of acetonitrile/aqueous buffer and of acetonitrile/acetic acid solutions.

  20. Using kinetic parameter analysis of dynamic FDOPA-PET for brain tissue classification

    NASA Astrophysics Data System (ADS)

    Lin, Hong-Dun; Lin, Kang-Ping; Chung, Being-Tau; Yu, Chin-Lung; Wang, Rong-Fa; Wu, Liang-Chi; Liu, Ren-Shyan

    2002-04-01

    In clinically, structural image based brain tissue segmentation as a preprocess plays an important and essential role on a number of image preprocessing, such as image visualization, object recognition, image registration, and so forth. However, when we need to classify the tissues according to their physiological functions, those strategies are not satisfactory. In this study, we incorporated both tissue time-activity curves (TACs) and derived kinetic parametric curves (KPCs) information to segment brain tissues, such as striatum, gray and white matters, in dynamic FDOPA-PET studies. Four common clustering techniques, K-mean (KM), Fuzzy C-mean (FCM), Isodata (ISO), Markov Random Fields (MRF), and our method were compared to evaluate its precision. The results show 41% and 48% less mean errors in mean difference for KPCs and TACs, respectively, than other methods. Combined KPCs and TACs based clustering method provide the ability to define brain structure effectively.

  1. Crystallization kinetics of lithium niobate glass: determination of the Johnson-Mehl-Avrami-Kolmogorov parameters.

    PubMed

    Choi, H W; Kim, Y H; Rim, Y H; Yang, Y S

    2013-06-28

    The formation of crystalline LiNbO3 (LN) from LN glass has been studied by means of differential scanning calorimetry and in situ synchrotron X-ray diffraction. The LN glass with no glass former was prepared by the polymerized complex method. The isothermal kinetics of the crystallization process is described using the Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation and the Avrami exponent n is found to be ~2.0, indicating that the crystallization mechanism is diffusion-controlled growth with a decreasing nucleation rate. The effective activation energy of crystallization calculated from isothermal measurements is 6.51 eV. It is found that the LN glass directly transforms into a rhombohedral LN crystal without any intermediate crystalline phase and most crystal grains are confined within the size of ~40 nm irrespective of different isothermal temperatures. Application of JMAK theory to the non-isothermal thermoanalytical study of crystallization of LN glass is discussed. PMID:23677338

  2. Action of human pancreatic and salivary alpha-amylases on maltooligosaccharides: evaluation of kinetic parameters.

    PubMed

    Saito, N; Horiuchi, T; Yoshida, M; Imai, T

    1979-10-01

    The kinetic studies on the reactions of human pancreatic and salivary alpha-amylases with several maltooligosaccharides (maltotetraose, maltopentaose, maltohexaose, and maltoheptaose) were carried out. The susceptibility to hydrolysis with human pancreatic alpha-amylase decreased in the order of maltopentaose, maltohexaose, maltotetraose, and maltoheptaose, while with human salivary alpha-amylase maltopentaose was hydrolysed slightly slower than maltohexaose but fairly faster than maltotetraose or maltoheptaose from a viewpoint of the rates of reactions based on the amount of substrate changed. The relative rates of production of substrates, utilized in the coupled yeast alpha-glucosidase reaction, increased in the order of maltoheptaose, maltohexaose, maltotetraose, and maltopentaose with human pancreatic alpha-amylase, while with human salivary alpha-amylase in the order of maltoheptaose, maltotetraose, maltohexaose, and maltopentaose. Thus, maltopentaose was considered to be the best substrate over maltotetraose, maltohexaose or maltoheptaose for the alpha-glucosidase coupled method of alpha-amylase determination. PMID:385176

  3. HCV-NS3 inhibitors: determination of their kinetic parameters and mechanism.

    PubMed

    Flores, María Victoria; Strawbridge, Joanne; Ciaramella, Giuseppe; Corbau, Romuald

    2009-10-01

    Existing HCV protease inhibitors fall into two categories: reversible and non-covalent, such as BILN-2061, and covalent and reversible, exemplified by SCH-503034 and VX-950. In this work, the characterization of the kinetics of these three inhibitors is presented. SCH-503034 and VX-950 initially bind to the genotype 1b HCV NS3/4A protease to form a low affinity complex, with K(i) values of 5 and 5.8 microM respectively. The ability of those two compounds to form a second covalent complex (EI) results in a potency increase, with overall K(i) values of 20 and 45 nM, respectively. The increase in potency can be explained by their slow dissociation rate, forming complexes with half-lives of 2 h (VX-950) and 5 h (SCH-503034). Although BILN-2061 has been described as a fast reversible, non-covalent inhibitor, our results show a slow binding two-step mechanism. Contrary to SCH-503034 and VX-950, BILN-2061 can form a high affinity first complex with a K(i) value of 3.9 nM, and an overall K(i) of 0.14 nM. The half-life of the BILN-2061 EI complex is shorter (t(1/2) approximately 0.7 h) than that of the other two compounds. The potency of these compounds is genotype dependent, and a kinetic analysis using NS3/4A from genotype 3a indicates that the loss of potency of SCH-503034 and VX-950 relative to genotype 1 is mainly due to the slow on-rate and faster off-rate for the formation of the EI complex. In the case of BILN-2061, a better fit is obtained using a one-step model, indicating that the loss of potency is due to an increase in the off-rate of the EI complex. PMID:19505593

  4. Degradation of ciprofloxacin in water by advanced oxidation process: kinetics study, influencing parameters and degradation pathways.

    PubMed

    Sayed, Murtaza; Ismail, M; Khan, Sanaullah; Tabassum, Safia; Khan, Hasan M

    2016-03-01

    Gamma-radiation-induced degradation of ciprofloxacin (CIP) in aqueous solution and the factors affecting the degradation process have been investigated. The results showed that CIP (4.6 mg/L) was almost completely degraded at an absorbed dose of 870 Gy. The kinetic studies of aqueous solutions containing 4.6, 10, 15 and 17.9 mg/L indicated that the decomposition of CIP by gamma irradiation followed pseudo-first-order kinetics and the decay constant (k) decreased from 5.9  ×  10(-3) to 1.6  ×  10(-3) Gy(-1) with an increase in CIP initial concentration from 4.6 to 17.9 mg/L. The effect of saturation of CIP solution with N2, N2O or air on radiation-induced degradation of CIP was also investigated. The effects of radical scavengers, such as t-BuOH and i-PrOH, showed the role of reactive radicals towards degradation of CIP in the order of [Formula: see text]. The apparent second-order rate constant of [Formula: see text] with CIP was calculated to be 2.64 × 10(9) M(-1) s(-1). The effects of solution pH as well as natural water contaminants, such as [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text], on CIP degradation by gamma-irradiation were also investigated. Major degradation products, including organic acids, were identified using UPLC-MS/MS and IC, and degradation pathways have been proposed. PMID:26208491

  5. The eye lens: age-related trends and individual variations in refractive index and shape parameters.

    PubMed

    Pierscionek, Barbara; Bahrami, Mehdi; Hoshino, Masato; Uesugi, Kentaro; Regini, Justyn; Yagi, Naoto

    2015-10-13

    The eye lens grows throughout life by cell accrual on its surface and can change shape to adjust the focussing power of the eye. Varying concentrations of proteins in successive cell layers create a refractive index gradient. The continued growth of the lens and age-related changes in proteins render it less able to alter shape with loss of capacity by the end of the sixth decade of life. Growth and protein ageing alter the refractive index but as accurate measurement of this parameter is difficult, the nature of such alterations remains uncertain. The most accurate method to date for measuring refractive index in intact lenses has been developed at the SPring-8 synchrotron. The technique, based on Talbot interferometry, has an X-ray source and was used to measure refractive index in sixty-six human lenses, aged from 16 to 91 years. Height and width were measured for forty-five lenses. Refractive index contours show decentration in some older lenses but individual variations mask age-related trends. Refractive index profiles along the optic axis have relatively flat central sections with distinct micro-fluctuations and a steep gradient in the cortex but do not exhibit an age-related trend. The refractive index profiles in the equatorial aspect show statistical significance with age, particularly for lenses below the age of sixty that had capacity to alter shape in vivo. The maximum refractive index in the lens centre decreases slightly with age with considerable scatter in the data and there are age-related variations in sagittal thickness and equatorial height. PMID:26416418

  6. The eye lens: age-related trends and individual variations in refractive index and shape parameters

    PubMed Central

    Pierscionek, Barbara; Bahrami, Mehdi; Hoshino, Masato; Uesugi, Kentaro; Regini, Justyn; Yagi, Naoto

    2015-01-01

    The eye lens grows throughout life by cell accrual on its surface and can change shape to adjust the focussing power of the eye. Varying concentrations of proteins in successive cell layers create a refractive index gradient. The continued growth of the lens and age-related changes in proteins render it less able to alter shape with loss of capacity by the end of the sixth decade of life. Growth and protein ageing alter the refractive index but as accurate measurement of this parameter is difficult, the nature of such alterations remains uncertain. The most accurate method to date for measuring refractive index in intact lenses has been developed at the SPring-8 synchrotron. The technique, based on Talbot interferometry, has an X-ray source and was used to measure refractive index in sixty-six human lenses, aged from 16 to 91 years. Height and width were measured for forty-five lenses. Refractive index contours show decentration in some older lenses but individual variations mask age-related trends. Refractive index profiles along the optic axis have relatively flat central sections with distinct micro-fluctuations and a steep gradient in the cortex but do not exhibit an age-related trend. The refractive index profiles in the equatorial aspect show statistical significance with age, particularly for lenses below the age of sixty that had capacity to alter shape in vivo. The maximum refractive index in the lens centre decreases slightly with age with considerable scatter in the data and there are age-related variations in sagittal thickness and equatorial height. PMID:26416418

  7. Sensitivity analysis of large system of chemical kinetic parameters for engine combustion simulation

    SciTech Connect

    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.

  8. Variation in biochemical parameters in different parts of potato tubers for processing purposes.

    PubMed

    Bandana; Sharma, Vineet; Kaushik, S K; Singh, Brajesh; Raigond, Pinky

    2016-04-01

    The present study was conducted to estimate the variation in bio-chemical parameters among eight different parts viz. bud end cortex, bud end medulla, central cortex, central medulla, pith, stem end cortex, stem end medulla and peel of potato tuber of processing varieties. Concentration of dry matter, reducing sugar, sucrose and starch content were higher in cortical region than in medullar region of stem end, bud end and central portion. Variety Kufri Chipsona-1 had maximum dry matter content in stem end cortex (SEC 30.34 %), followed by Kufri Frysona (SEC 27.71 %). Mean reducing sugar values were comparatively more in bud end cortex (BEC 111.3 mg/100 g Fresh Weight) and lowest in stem end medulla (SEM 44.05 mg/100 g FW). Bio-chemical contents varied considerably within different parts of tuber as well as in different genotypes. The information generated in this study can help processors for effective utilization of potato for various types of processing products viz., chips and French fries. PMID:27413232

  9. Variation in climate sensitivity and feedback parameters during the historical period

    NASA Astrophysics Data System (ADS)

    Gregory, J. M.; Andrews, T.

    2016-04-01

    We investigate the climate feedback parameter α (W m-2 K-1) during the historical period (since 1871) in experiments using the HadGEM2 and HadCM3 atmosphere general circulation models (AGCMs) with constant preindustrial atmospheric composition and time-dependent observational sea surface temperature (SST) and sea ice boundary conditions. In both AGCMs, for the historical period as a whole, the effective climate sensitivity is ˜2 K (α≃1.7 W m-2 K-1), and α shows substantial decadal variation caused by the patterns of SST change. Both models agree with the AGCMs of the latest Coupled Model Intercomparison Project in showing a considerably smaller effective climate sensitivity of ˜1.5 K (α = 2.3 ± 0.7 W m-2 K-1), given the time-dependent changes in sea surface conditions observed during 1979-2008, than the corresponding coupled atmosphere-ocean general circulation models (AOGCMs) give under constant quadrupled CO2 concentration. These findings help to relieve the apparent contradiction between the larger values of effective climate sensitivity diagnosed from AOGCMs and the smaller values inferred from historical climate change.

  10. Parameter-specific electronic measurement and analysis of sources of variation using ring oscillators

    NASA Astrophysics Data System (ADS)

    Wang, Lynn T.-N.; Pang, Liang-Teck; Neureuther, Andrew R.; Nikolić, Borivoje

    2009-03-01

    Parameter-specific and simulation-calibrated ring oscillator (RO) inverter layouts are described for identifying and quantitatively modeling sources of circuit performance variation from source/drain stress, shallow trench isolation (STI) stress, lithography, etch, and misalignment. This paper extends the RO approach by adding physical modeling/simulation of the sources of variability to tune the layouts of monitors for enhanced sensitivity and selectivity. Poly and diffusion layout choices have been guided by fast-CAD pattern matching. The accuracy of the fast-CAD estimate from the Pattern Matcher for these lithography issues is corroborated by simulations in Mentor Graphics Calibre. Generic conceptual results are given based on the experience from preparing of proprietary layouts that pass DRC check for a 45 nm test chip with ST Micro. Typical improvements in sensitivity of 2 fold are possible with layouts for lithography focus. A layout monitor for poly to diffusion misalignment based on programmable off-sets shows a 0.8% change in RO frequency per 1nm poly to diffusion off-set. Layouts are also described for characterizing stress effects associated with diffusion area size, asymmetry, vertical spacing, and multiple gate lengths.

  11. Spatial and temporal variations of reddening parameters toward HII regions in the Milky Way galaxy

    NASA Astrophysics Data System (ADS)

    Vargas Alvarez, Carlos A.

    The purpose of this thesis is to determine if the value of the total-to-selective extinction ratio, RV, has spatial and temporal variations as dust is modified by UV photons. Historically this value has been assumed to be 3.1 after averaging the values along different sightlines in the Milky Way Galaxy. This work will also demonstrate, that for areas of recent star formation with heavy extinction a proper study can not be done when assuming the nominal value, but a local value of RV must first be determined. For this purpose I will analyze the reddening parameters RV and A V toward the massive cluster Westerlund 2 and several mid-IR bubbles located in the G38.91-0.42 complex. Three reddening laws that made different assumptions about RV are applied to the spectral energy distribution (SED) of the observed stars. These SEDs are compared to the available optical and IR photometry searching for the RV and AV that minimizes the chi 2 of the fit.

  12. DIRECTIONAL VARIATIONS OF THE NON-GAUSSIANITY PARAMETER f{sub NL}

    SciTech Connect

    Rudjord, Oeystein; Hansen, Frode K.; Lan Xiaohong; Marinucci, Domenico; Liguori, Michele; Matarrese, Sabino

    2010-01-10

    We investigate local variations of the primordial non-Gaussianity parameter f{sub NL} in the WMAP data, looking for possible influence of foreground contamination in the full-sky estimate of f{sub NL}. We first improve the needlet bispectrum estimate in Rudjord et al. on the full sky to f{sub NL} = 73 +- 31 using the KQ75 mask on the co-added V + W channel. We find no particular values of f{sub NL} estimates close to the galactic plane and conclude that foregrounds are unlikely to affect the estimate of f{sub NL} in the V and W bands even for the smaller KQ85 mask. In the Q band, however, we find unexpectedly high values of f{sub NL} in local estimates close to the galactic mask, as well as significant discrepancies between Q-band estimates and V/W-band estimates. We therefore conclude that the Q band is too contaminated to be used for non-Gaussianity studies even with the larger KQ75 mask. We further note that the local f{sub NL} estimates on the V + W channel are positive on all equatorial bands from the north to the south pole. The probability for this to happen in a universe with f{sub NL} = 0 is less than 1%.

  13. Experimental study of meteorological parameters variation using hf-signal during solar proton events

    NASA Astrophysics Data System (ADS)

    Goncharenko, Yu.; Gutnik, V.; Kivva, F.

    Nowadays there are many experimental facts showing the Solar activity influence on a weather and climate. Nevertheless we still do not have a model explaining all the problems of Solar-terrestrial links. This lack is due to the deficit of the experimental data about variations of the meteorological conditions before, during and after a solar flare. This type of data could be obtained by use of weather balloon, rocket or aircraft sounding, etc. But all of these methods could not be used for achieving of large arrays of continuous data due to their large cost. Refractive index, which plays a significant role in radiowave propagation, relates to the main meteorological parameters such as temperature, pressure and vapor pressure [1]. So, statistical studies of the signal level variation processes can give some information about meteorological processes in troposphere. To solve this problem an experimental radio link from telecommunication satellite Asiasat-3S (elevation angle in Kharkov, Ukraine is 4.5o) was constructed. The experiment was carried out from May-2002 till November-2003 at the frequency 3.6GHz. More than 20 solar flare events were analyzed. It was found that during strong solar flare with proton flux index (p.f.u.) >200 a deep rapid fading appears. The fading rate of the signal increased in 10-15 times at the level -6dB and in 5-10 times at the level -4dB from the signal mean value in 3-6 hours after solar flare had begun. It is necessary to note that during solar flare with p.f.u <200 this effects are not registered. The duration of the signal fading increased, too. Two to three days later the behavior of the received signal returns to the normal, non-flare state. This fading can be connected to phenomena of the interference between few signals originating at different sources like tropospheric inhomogeneouses and the satellite. These inhomogeneouses are linked to small-scale fluctuation of refractive index. It is necessary to note that radio waves

  14. Kinetic parameters and relative turnovers of some important catabolic reactions in digesting sludge.

    PubMed Central

    Kaspar, H F; Wuhrmann, K

    1978-01-01

    The kinetics of propionate degradation, acetate splitting, and hydrogen consumption in digesting sludge were investigated in a lab-scale digester. At natural steady-state conditions, the acetate-splitting systems in well-digested sludge were about half saturated. Propionate-degrading systems were saturated to only 10 to 15%, and hydrogen removal was less than 1% of the maximum possible rate. It was concluded that acetate splitting rather than "methanogenesis from fatty acids" is the rate-limiting reaction in the anaerobic degradation of dissolved organic matter and that a methoanogenic anaerobic ecosystem is stabilized by its large unused capacity of hydrogen consumption which is "buffering" the partial pressure of dissolved hydrogen in the system at sufficiently low values to permit rapid fatty acid oxidation. A tentative scheme of the substrate flow in sludge digestion is presented. It suggests that acid formation coupled with hydrogen formation via pyridine dinucleotide oxidation yields the immediate substrates, namely acetate and hydrogen, for about 54% of the total methanogenesis. PMID:697354

  15. Quantifiable patterns of limb loading and unloading during hemiparetic gait: Relation to kinetic and kinematic parameters

    PubMed Central

    Raja, Bhavana; Neptune, Richard R.; Kautz, Steven A.

    2016-01-01

    Persons with poststroke hemiparesis are characterized by asymmetry in limb loading (LL) and limb unloading (LU), which has been reported in static and quasi-static tasks but has not been quantified during walking. The purpose of this study was to determine the asymmetry in magnitude and duration of LL and LU in individuals with hemiparesis and its relationship with functional walking status and specific kinematic and kinetic variables during walking. Forty-four participants with chronic hemiparesis walked at their self-selected speeds and eighteen nondisabled control subjects of similar ages walked at predetermined matched speeds while three-dimensional ground reaction forces and body-segment kinematics were recorded. Magnitude of paretic LL was reduced, while duration was increased compared with the nonparetic leg and nondisabled controls walking at matched speeds. The paretic LL and LU was significantly correlated with average leg angle, while the nonparetic leg significantly correlated with average knee angle. Three different patterns of LL and LU were identified (concave, convex, and linear). Individuals with hemiparesis make several biomechanical adjustments that minimize LL of the paretic leg. LL deviations were more pronounced with increased lateral placement of the paretic foot and with decreased functional gait speed. Characterization of these deviations may inspire new strategies for rehabilitation. PMID:23408212

  16. Influence of process parameters on the reaction kinetics of the chromium-catalyzed trimerization of ethylene.

    PubMed

    Wöhl, Anina; Müller, Wolfgang; Peitz, Stephan; Peulecke, Normen; Aluri, Bhaskar R; Müller, Bernd H; Heller, Detlef; Rosenthal, Uwe; Al-Hazmi, Mohammed H; Mosa, Fuad M

    2010-07-12

    In this paper we report the results of an extensive experimental kinetic study carried out on the novel ethylene trimerization catalyst system, comprising the chromium source [CrCl(3)(thf)(3)] (thf=tetrahydrofuran), a Ph(2)P-N(iPr)-P(Ph)-N(iPr)H (PNPNH) ligand (Ph=phenyl, iPr=isopropyl), and triethylaluminum (AlEt(3)) as activator. It could be shown that the initial activity shows a first-order dependency on the ethylene concentration. Also, a first-order dependency was found for the catalyst concentration. The initial activity follows a typical Arrhenius behavior with an experimentally determined activation energy of 52.6 kJ mol(-1). At elevated temperatures (ca. 80 degrees C), a significant deactivation was observed, which can be tentatively traced back to a ligand rearrangement in the presence of AlEt(3). After a fast initial phase, a pronounced 'kink' in the ethylene-uptake curve is observed, followed by a slow, almost linear, further increase of the total ethylene consumption. The catalyst composition, in particular the ligand/chromium and the cocatalyst/chromium molar ratio, has a strong impact on the catalytic performance of the trimerization of ethylene. PMID:20512824

  17. Ethylene vinyl acetate based radiation grafted hydrophilic matrices: Process parameter standardization, grafting kinetics and characterization

    NASA Astrophysics Data System (ADS)

    Chaudhari, C. V.; Mondal, R. K.; Dubey, K. A.; Grover, V.; Panicker, L.; Bhardwaj, Y. K.; Varshney, L.

    2016-08-01

    A transparent, elastomeric, grafted matrix for several potential applications was synthesized by single-step simultaneous radiation grafting of methacrylic acid onto ethylene vinyl acetate (EVA). CuSO4 was found to be the most suitable homo-polymerization inhibitor among different inhibitors tried. The grafting kinetics was found to be a strong function of dose rate (D) and monomer content (M) and an equation relating grafting rate Rg=Kg [M]1.13D0.23 was deduced. Crystallinity of the grafted matrices as assessed from XRD and DSC measurements indicated decrease in crystalline content with increase in grafting yield, suggesting crystalline domain of EVA get disrupted on grafting. Elastic modulus increased linearly with the increase in grafting yield, though elongation at break decreased precipitously from 900% to 30% at even ~9% grafting. Thermo-gravimetric analysis showed three step weight loss of the grafted EVA matrix. The grafting of MAA resulted in increase in surface energy mainly due to enhanced polar component.

  18. Kinetics Parameters of VVER-1000 Core with 3 MOX Lead Test Assemblies To Be Used for Accident Analysis Codes

    SciTech Connect

    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.

  19. Visualization and Curve-Parameter Estimation Strategies for Efficient Exploration of Phenotype Microarray Kinetics

    PubMed Central

    Vaas, Lea A. I.; Sikorski, Johannes; Michael, Victoria; Göker, Markus; Klenk, Hans-Peter

    2012-01-01

    Background The Phenotype MicroArray (OmniLog® PM) system is able to simultaneously capture a large number of phenotypes by recording an organism's respiration over time on distinct substrates. This technique targets the object of natural selection itself, the phenotype, whereas previously addressed ‘-omics’ techniques merely study components that finally contribute to it. The recording of respiration over time, however, adds a longitudinal dimension to the data. To optimally exploit this information, it must be extracted from the shapes of the recorded curves and displayed in analogy to conventional growth curves. Methodology The free software environment R was explored for both visualizing and fitting of PM respiration curves. Approaches using either a model fit (and commonly applied growth models) or a smoothing spline were evaluated. Their reliability in inferring curve parameters and confidence intervals was compared to the native OmniLog® PM analysis software. We consider the post-processing of the estimated parameters, the optimal classification of curve shapes and the detection of significant differences between them, as well as practically relevant questions such as detecting the impact of cultivation times and the minimum required number of experimental repeats. Conclusions We provide a comprehensive framework for data visualization and parameter estimation according to user choices. A flexible graphical representation strategy for displaying the results is proposed, including 95% confidence intervals for the estimated parameters. The spline approach is less prone to irregular curve shapes than fitting any of the considered models or using the native PM software for calculating both point estimates and confidence intervals. These can serve as a starting point for the automated post-processing of PM data, providing much more information than the strict dichotomization into positive and negative reactions. Our results form the basis for a freely

  20. Multidimensional Voice Program (MDVP) and amplitude variation parameters in euphonic adult subjects. Normative study.

    PubMed

    Nicastri, M; Chiarella, G; Gallo, L V; Catalano, M; Cassandro, E

    2004-12-01

    The introduction, in the late 70s, of the first digital spectrograph (DSP Sonograph) by Kay Elemetrics has improved the possibilities of spectroacoustic voice analysis in the clinical field. Thanks to the marketing, in 1993, of the Multi Dimensional Voice Program (MDVP) advanced system, it is now possible to analyse 33 quantitative voice parameters which, in turn, allow evaluation of fundamental frequency, amplitude and spectral energy balance and the presence of any sonority gap and diplophony. Despite its potentials, the above-mentioned system is not widely used yet, partly on account of the lack of a standard procedure. Indeed, there are still only a few case reports in the literature taking into consideration prescriptive aspects related both to procedure and analysis. This study aims to provide the results of amplitude perturbation parameter analysis in euphonic adult patients. In our opinion, these are the most significant parameters in determining the severity of a phonation disorder. The study has been carried out on 35 patients (24 female, 11 male, mean age 31.6 years, range 19-59). The voice signal has been recorded using a 4300 B Kay Computer Speech Lab (CSL) supported by a personal computer including a SM48 Shure-Prolog microphone located at a distance of 15 cm and angled at 45 degrees. Input microphone saturation has been adjusted to 6/9 of the CH1 channel. The voice sample consisted in a held /a/ and the analysis has been carried out on the central 3 seconds of the recording. The analysis has been carried out using a 5105 MDVP software version 2.3 and the signal digitalised at a 50 kHz sample rate. In order for the sample to be as free from intensity or frequency changes as possible, each patient underwent a training session (including at least 3 phonation tests) before the recording. The study included only emissions between 55 and 65 dB and with spectrum stability. Environmental noise has constantly been monitored and maintained below 30 dB. Data

  1. Mainz Organics Mechanism (MOM): description and sensitivity to some estimated kinetic parameters

    NASA Astrophysics Data System (ADS)

    Taraborrelli, Domenico; Cabrera Perez, David; Sander, Rolf; Pozzer, Andrea

    2015-04-01

    Despite decades of reasearch, global atmospheric chemistry models still have significant biases compared to the estimated distribution and evolution of tropospheric ozone and hydroxyl radical. The gas-phase oxidation of volatile organic compounds (VOC) is acknowledged to play an important role among the processes affecting tropospheric ozone, methane lifetime and aerosol evolution. Thus, chemical mechanisms of very diverse complexity have been developed for the major VOCs. However, all mechanisms present shortcomings such as neglection or lumping of intermediates and estimate of many rate constants and product distributions. Here, we present a VOC oxidation mechanism of intermediate complexity called the Mainz Organics Mechanism (MOM). With about 400 species and 1500 reactions, it represents the oxidation of about 20 primarily emitted VOCs comprising small alkanes and alkenes, isoprene, pinenes and monocyclic aromatic compounds. The development protocol significantly borrows from the Master Chemical Mechanism (MCM). However, MOM distinguishes itself for a number of features. First, the structure activity relationship for estimating the rate constants involving hydroxyl radical is site-specific and dependent on temperature. Second, the alkyl nitrate yields are considered to be dependent on temperature, pressure and molecular structure. RO2 + HO2 reaction kinetics is consistent with the recent direct studies of \\chem{OH}-reformation. Isoprene chemistry includes the latest experimental advancements with respect to OH-recycling and alkyl nitrate chemistry. Pinenes chemistry is largely the one by the MCM but with some modifications according to the work of the Leuven's group. Finally, the chemistry of the aromatics is also borrowed from the MCM but with additional photolysis of ortho-nitrophenols leading to \\chem{HONO} formation. The sensitivity of the model to the temperature and pressure dependence of estimated \\chem{OH} rate constants and alkyl nitrate yields will

  2. Real time kinetic flow cytometry measurements of cellular parameter changes evoked by nanosecond pulsed electric field.

    PubMed

    Orbán, Csaba; Pérez-García, Esther; Bajnok, Anna; McBean, Gethin; Toldi, Gergely; Blanco-Fernandez, Alfonso

    2016-05-01

    Nanosecond pulsed electric field (nsPEF) is a novel method to increase cell proliferation rate. The phenomenon is based on the microporation of cellular organelles and membranes. However, we have limited information on the effects of nsPEF on cell physiology. Several studies have attempted to describe the effects of this process, however no real time measurements have been conducted to date. In this study we designed a model system which allows the measurement of cellular processes before, during and after nsPEF treatment in real time. The system employs a Vabrema Mitoplicator(TM) nsPEF field generating instrument connected to a BD Accuri C6 cytometer with a silicon tube led through a peristaltic pump. This model system was applied to observe the effects of nsPEF in mammalian C6 glioblastoma (C6 glioma) and HEK-293 cell lines. Viability (using DRAQ7 dye), intracellular calcium levels (using Fluo-4 dye) and scatter characteristics were measured in a kinetic manner. Data were analyzed using the FACSKin software. The viability and morphology of the investigated cells was not altered upon nsPEF treatment. The response of HEK-293 cells to ionomycin as positive control was significantly lower in the nsPEF treated samples compared to non-treated cells. This difference was not observed in C6 cells. FSC and SSC values were not altered significantly by the nsPEF treatment. Our results indicate that this model system is capable of reliably investigating the effects of nsPEF on cellular processes in real time. © 2016 International Society for Advancement of Cytometry. PMID:26990601

  3. Kinetics and strain variation of phagosome proteins of Entamoeba histolytica by proteomic analysis.

    PubMed

    Okada, Mami; Huston, Christopher D; Oue, Miho; Mann, Barbara J; Petri, William A; Kita, Kiyoshi; Nozaki, Tomoyoshi

    2006-02-01

    The protozoan parasite Entamoeba histolytica ingests and feeds on microorganisms and mammalian cells. Phagocytosis is essential for cell growth and implicated in pathogenesis of E. histolytica. We report here the dynamic changes of phagosome proteins during phagosome maturation by proteomic analysis using reversed-phase capillary liquid chromatography and ion trap tandem mass spectrometry. Phagosomes were isolated at various intervals after internalization of latex beads. Immunoblot analysis and electron microscopy verified successful isolation of phagosomes. A total of 159 proteins were identified from the reference strain HM1 at different stages of phagosome maturation. Approximately 70% of them were detected in a time-dependent fashion, suggesting dynamism of phagosome biogenesis. The kinetics of representative proteins were verified by immunoblots and also by video microscopy of live transgenic amebae expressing green fluorescent protein-fused EhRab7A. Furthermore, we observed significant differences in phagosome profiles between HM1 and two recent clinical isolates. Approximately 60% of 229 proteins detected in at least one of these three strains were identified only in one strain, while approximately 20% of these proteins were detected in all three strains. These data should provide significant insights into molecular characterization of phagosome biogenesis, and help to elucidate the pathogenesis of this important infection. PMID:16290089

  4. Deciphering the impact of parameters influencing transgene expression kinetics after repeated cell transduction with integration-deficient retroviral vectors.

    PubMed

    Schott, Juliane W; Jaeschke, Nico M; Hoffmann, Dirk; Maetzig, Tobias; Ballmaier, Matthias; Godinho, Tamaryin; Cathomen, Toni; Schambach, Axel

    2015-05-01

    Lentiviral and gammaretroviral vectors are state-of-the-art tools for transgene expression within target cells. The integration of these vectors can be deliberately suppressed to derive a transient gene expression system based on extrachromosomal circular episomes with intact coding regions. These episomes can be used to deliver DNA templates and to express RNA or protein. Importantly, transient gene transfer avoids the genotoxic side effects of integrating vectors. Restricting their applicability, episomes are rapidly lost upon dilution in dividing target cells. Addressing this limitation, we could establish comparably stable percentages of transgene-positive cells over prolonged time periods in proliferating cells by repeated transductions. Flow cytometry was applied for kinetic analyses to decipher the impact of individual parameters on the kinetics of fluoroprotein expression after episomal retransduction and to visualize sequential and simultaneous transfer of heterologous fluoroproteins. Expression windows could be exactly timed by the number of transduction steps. The kinetics of signal loss was affected by the cell proliferation rate. The transfer of genes encoding fluoroproteins with different half-lives revealed a major impact of protein stability on temporal signal distribution and accumulation, determining optimal retransduction intervals. In addition, sequential transductions proved broad applicability in different cell types and using different envelope pseudotypes without receptor overload. Stable percentages of cells coexpressing multiple transgenes could be generated upon repeated coadministration of different episomal vectors. Alternatively, defined patterns of transgene expression could be recapitulated by sequential transductions. Altogether, we established a methodology to control and adjust a temporally defined window of transgene expression using retroviral episomal vectors. Combined with the highly efficient cell entry of these vectors while

  5. Variations in Kinetic Properties of Ribulose-1,5-bisphosphate Carboxylases among Plants

    PubMed Central

    Yeoh, Hock-Hin; Badger, Murray R.; Watson, Leslie

    1981-01-01

    Studies of ribulose-1,5-bisphosphate (RuBP) carboxylase from taxonomically diverse plants show that the enzyme from C3 and crassulacean acid metabolism pathway species exhibits lower Km(CO2) values (12-25 micromolar) than does that from C4 species (28-34 micromolar). RuBP carboxylase from aquatic angiosperms, an aquatic bryophyte, fresh water and marine algae has yielded consistently high Km(CO2) values (30-70 micromolar), similar in range to that of the enzyme from C4 terrestrial plants. This variation in Km(CO2) is discussed in relation to the correlation between the existence of CO2-concentrating mechanisms for photosynthesis and the affinity of the enzyme for CO2. The Km(RuBP) of the enzyme from various sources ranges from 10 to 136 micromolar; mean ± sd = 36 ± 20 micromolar. This variation in Km(RuBP) does not correlate with different photosynthetic pathways, but shows taxonomic patterns. Among the dicotyledons, the enzyme from crassinucellate species exhibits lower Km(RuBP) (18 ± 4 micromolar) than does that from tenuinucellate species (25 ± 7 micromolar). Among the Poaceae, RuBP carboxylase from Triticeae, chloridoids, andropogonoids, Microlaena, and Tetrarrhena has yielded lower Km(RuBP) values (29 ± 11 micromolar) than has that from other members of the grass family (46 ± 10 micromolar). PMID:16661826

  6. Esterase in imported fire ants, Solenopsis invicta and S. richteri (Hymenoptera: Formicidae): activity, kinetics and variation.

    PubMed

    Chen, J; Rashid, T; Feng, G

    2014-01-01

    Solenopsis invicta and Solenopsis richteri are two closely related invasive ants native to South America. Despite their similarity in biology and behavior, S. invicta is a more successful invasive species. Toxic tolerance has been found to be important to the success of some invasive species. Esterases play a crucial role in toxic tolerance of insects. Hence, we hypothesized that the more invasive S. invicta would have a higher esterase activity than S. richteri. Esterase activities were measured for workers and male and female alates of both ant species using α-naphthyl acetate and β-naphthyl acetate as substrates. Esterase activities in S. invicta were always significantly higher than those in S. richteri supporting our hypothesis. In S. invicta, male alates had the highest esterase activities followed by workers then female alates for both substrates. In S. richetri, for α-naphthyl acetate, male alates had the highest activity followed by female alates then workers, while for β-naphthyl acetate, female alates had the highest activity followed by male alates then workers. For workers, S. richteri showed significantly higher levels of variation about the mean esterase activity than S. invicta. However, S. invicta showed significantly higher levels of variation in both female and male alates. PMID:25408118

  7. Determination of kinetic and thermodynamic parameters that describe isothermal seed germination: A student research project

    NASA Astrophysics Data System (ADS)

    Hageseth, Gaylord T.

    1982-02-01

    Students under the supervision of a faculty member can collect data and fit the data to the theoretical mathematical model that describes the rate of isothermal seed germination. The best-fit parameters are interpreted as an initial substrate concentration, product concentration, and the autocatalytic reaction rate. The thermodynamic model enables one to calculate the activation energy for the substrate and product, the activation energy for the autocatalytic reaction, and changes in enthalpy, entropy, and the Gibb's free energy. Turnip, lettuce, soybean, and radish seeds have been investigated. All data fit the proposed model.

  8. Removal of Anionic Dyes from Water by Potash Alum Doped Polyaniline: Investigation of Kinetics and Thermodynamic Parameters of Adsorption.

    PubMed

    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. PMID:26079693

  9. Photooxidative degradation of Acid Red 27 (AR27): modeling of reaction kinetic and influence of operational parameters.

    PubMed

    Daneshvar, Nezameddin; Rabbani, Mohammad; Modirshahla, Nasser; Behnajady, Mohammad-Ali

    2004-01-01

    The decolorization and mineralization of Acid Red 27 (AR27), an anionic monoazo dye of acid class, were studied by UV/H202 process in laboratory and real samples. Effects of different process parameters such as initial H2O2 and AR27 concentrations, pH and EtOH as an electron scavenger have been studied. H2O2 and UV light have a negligible effect when they were used on their own. The decolorization rate follows pseudo-first order kinetic with respect to the dye concentration. The rate constant of the attack of *OH radicals to the AR27 has been estimated through the adoption of a simplified kinetic model (1.03 x 10(8)M(-1)s(-1)). This model allows predicting the pseudo-first order rate constant and concentration of AR27 in different illumination times for different initial concentrations of H2O2. Mineralization studies showed, the formation of sulfate ions, the decrease of pH and 85% of COD reduction occur in less than 60 min. In the real wastewater color removal could be achieved after only 75 min, whereas 45% of COD reduction occurs after 105 min of illumination. PMID:15478925

  10. Micropollutant biotransformation kinetics associate with WWTP process parameters and microbial community characteristics.

    PubMed

    Helbling, Damian E; Johnson, David R; Honti, Mark; Fenner, Kathrin

    2012-10-01

    The objective of this work was to identify relevant wastewater treatment plant (WWTP) parameters and underlying microbial processes that influence the biotransformation of a diverse set of micropollutants. To do this, we determined biotransformation rate constants for ten organic micropollutants in batch reactors seeded with activated sludge from ten diverse WWTPs. The estimated biotransformation rate constants for each compound ranged between one and four orders of magnitude among the ten WWTPs. The biotransformation rate constants were tested for statistical associations with various WWTP process parameters, amoA transcript abundance, and acetylene-inhibited monooxygenase activity. We determined that (i) ammonia removal associates with oxidative micropollutant biotransformation reaction rates; (ii) archaeal but not bacterial amoA transcripts associate with both ammonia removal and oxidative micropollutant biotransformation reaction rates; and (iii) the activity of acetylene-inhibited monooxygenases (including ammonia monooxygenase) associates with ammonia removal and the biotransformation rate of isoproturon, but does not associate with all oxidative micropollutant biotransformations. In combination, these results lead to the conclusion that ammonia removal and amoA transcript abundance can potentially be predictors of oxidative micropollutant biotransformation reactions, but that the biochemical mechanism is not necessarily linked to ammonia monooxygenase activity. PMID:22938719

  11. The kinetic Sunyaev-Zel'dovich signal from inhomogeneous reionization: a parameter space study

    NASA Astrophysics Data System (ADS)

    Mesinger, Andrei; McQuinn, Matthew; Spergel, David N.

    2012-05-01

    Inhomogeneous reionization acts as a source of arcminute-scale anisotropies in the cosmic microwave background (CMB), the most important of which is the kinetic Sunyaev-Zel'dovich (kSZ) effect. Observational efforts with the Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT) are poised to detect this signal for the first time, with projected 1 μ K2-level sensitivity to the dimensionless kSZ power spectrum around a multipole of l= 3000, [Δl3000]2. Indeed, recent SPT measurements place a bound of [Δl3000 ]2 < 2.8 μ K2 at 95 per cent confidence level, which degrades to [Δl3000 ]2 < 6 μ K2 if a significant correlation between the thermal Sunyaev-Zel'dovich (tSZ) effect and the cosmic infrared background (CIB) is allowed. To interpret these and upcoming observations, we compute the kSZ signal from a suite of ≈100 reionization models using the publicly available code 21CMFAST. Our physically motivated reionization models are parametrized by the ionizing efficiency of high-redshift galaxies, the minimum virial temperature of haloes capable of hosting stars, and the ionizing photon mean free path - a parametrization motivated by previous theoretical studies of reionization. We predict the contribution of patchy reionization to the l= 3000 kSZ power to be ? 1.5-3.5 μ K2. Therefore, even when adopting the lowest estimate in the literature for the post-reionization signal of ?, none of our models are consistent with the aggressive 2σ SPT bound that does not include correlations. This implies the following: (i) the early stages of reionization occurred in a much more homogeneous manner than suggested by the stellar-driven scenarios we explore, such as would be the case if, e.g. very high energy X-rays or exotic particles contributed significantly and/or (ii) that there is a significant correlation between the CIB and the tSZ. The later is perhaps not surprising, as massive haloes should host both hot gas and star-forming galaxies. On the other hand

  12. Modelling Escherichia coli concentration in a wastewater reservoir using an operational parameter MRT%FE and first order kinetics.

    PubMed

    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. PMID:18222594

  13. Relationship Between Human Physiological Parameters And Geomagnetic Variations Of Solar Origin

    NASA Astrophysics Data System (ADS)

    Dimitrova, S.

    This study attempts to assess the influence of increased geomagnetic activity on some human physiological parameters. The blood pressure, heart rate and general well-being of 86 volunteers were measured (the latter by means of a standardized questionnaire) on work days in autumn 2001 (01/10 to 09/11) and in spring 2002 (08/04 to 28/05). These periods were chosen because of maximal expected geomagnetic activity. Altogether, 2799 recordings were obtained and analysed. MANOVA was employed to check the significance of the influence of three factors on the physiological parameters under consideration. The three factors were the following: 1) planetary geomagnetic activity level estimated by Ap-index and divided into five levels; 2) gender - males and females; 3) blood pressure degree - persons in the group examined were divided into hypotensive, normotensive and hypertensive. Post hoc analysis was performed to elicit the significance of differences in the factors' levels. The average arterial blood pressure of the group was found to increase significantly with the increase of geomagnetic activity level. The average increment of systolic and diastolic blood pressure reached 9%, which deserves attention from a medical point of view. This effect was present irrespectively of gender. Results obtained suppose that hypertensive persons have the highest sensitivity and the hypotensive persons have the lowest sensitivity of the arterial blood pressure to increase of geomagnetic activity. The results did not show significant changes in the heart rate. The percentage of the persons who reported subjective psycho-physiological complaints was also found to increase significantly with the geomagnetic activity increase. During severe geomagnetic storms 30% of the persons examined reported subjective complaints and the highest sensitivity was revealed for the hypertensive females. The results obtained add further evidence that blood pressure seems to be affected by geomagnetic

  14. On the shape of bottle-brush macromolecules: Systematic variation of architectural parameters

    NASA Astrophysics Data System (ADS)

    Rathgeber, Silke; Pakula, Tadeusz; Wilk, Agnieszka; Matyjaszewski, Krzysztof; Beers, Kathryn L.

    2005-03-01

    We measured the form factor of bottle-brush macromolecules under good solvent conditions with small-angle neutron scattering and static light scattering. The systems under investigation are brushes, synthesized via the grafting-from route, built from a poly(alkyl methacrylate) backbone to which poly(n-butyl acrylate) side chains are densely grafted. The aim of our work is to study how the systematic variation of structural parameters such as the side chain length and backbone length change the conformation of the polymer brushes in solution. All spectra can be consistently described by a model, considering the bottle-brush polymers as flexible rods with internal density fluctuations. Parameters discussed are (1) the contour length per main chain monomer lb, (2) the fractal dimension of the side chains Ds, as well as (3) the fractal dimension D, and (4) the Kuhn length λk of the overall brush. lb=0.253±0.008nm is found to be independent of the side chain length and equal to the value found for the bare main chain, indicating a strongly stretched conformation for the backbone due to the presence of the side chains. The fractal dimension of the side chains is determined to be Ds=1.75±0.07 which is very close to the value of 1/0.588≈1.70 expected for a three-dimensional self-avoiding random walk (3D-SAW) under good solvent conditions. On larger length scales the overall brush appears to be a 3D-SAW itself (D=1.64±0.08) with a Kuhn-step length of λk=70±4nm. The value is independent of the side chain length and 46 times larger than the Kuhn length of the bare backbone (λk=1.8±0.2nm). The ratio of Kuhn length to brush diameter λk/d⩾20 determines whether lyotropic behavior can be expected or not. Since longer side chains do not lead to more persistent structures, λk/d decreases from 8 to 4 with increasing side chain length and lyotropic behavior becomes unlikely.

  15. Determination of kinetic parameters of crystal growth rate of borax in aqueous solution by using the rotating disc technique

    NASA Astrophysics Data System (ADS)

    Sahin, Omer; Aslan, Fevzi; Ozdemir, Mustafa; Durgun, Mustafa

    2004-10-01

    Growth rate of polycrystalline disc of borax compressed at different pressure and rotated at various speed has been measured in a rotating disc crystallizer under well-defined conditions of supersaturation. It was found that the mass transfer coefficient, K, increased while overall growth rate constant, Kg, and surface reaction constant, kr, decreased with increasing smoothness of the disc. It was also determined that kinetic parameters (kr , r , K , g) of crystal growth rate of borax decreased with increasing rotating speed of the polycrystalline disc. The effectiveness factor was calculated from the growth rate data to evaluate the relative magnitude of the steps in series bulk diffusion through the mass transfer boundary layer and the surface integration. At low rotating speed of disc, the crystal growth rate of borax is mainly controlled by integration. However, both diffusion and integration steps affect the growth rate of borax at higher rotating speed of polycrystalline disc.

  16. Morphological Manipulation of Solvothermal Prepared CdSe Nanostructures by Controlling the Growth Rate of Nanocrystals as a Kinetic Parameter

    NASA Astrophysics Data System (ADS)

    Zarghami, V.; Mohammadi, M. R.; Fray, D. J.

    2012-11-01

    The morphological manipulation, structural characterization, and optical properties of different cadmium selenide (CdSe) nanostructures are reported. Two different CdSe nanostructures, i.e., nanorods and nanoparticles, were grown by controlling the concentration of precursors (i.e., cadmium nitrate and selenium dioxide) in ethanolamine solvent. By manipulating the kinetic parameter of the process (i.e., growth rate) under constant growth driving force (i.e., degree of supersaturation), the morphology of CdSe nanostructures can be tailored from nanorods to nanoparticles. The optical properties of CdSe nanostructures were investigated using ultraviolet-visible (UV-vis) spectroscopy. The absorption edge of the samples showed a blue-shift. CdSe nanostructures prepared under optimized conditions showed good microstructural and optical properties for solar cell applications.

  17. Thermoluminescence dosimetry properties and kinetic parameters of lithium potassium borate glass co-doped with titanium and magnesium oxides.

    PubMed

    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. PMID:24929526

  18. Indoor and outdoor atmospheric ion mobility spectra, diurnal variation, and relationship with meteorological parameters

    NASA Astrophysics Data System (ADS)

    Wright, Matthew D.; Holden, Nicola K.; Shallcross, Dudley E.; Henshaw, Denis L.

    2014-03-01

    We report measurements of small ion mobility spectra and concentrations made over a 5 month period using a Gerdien-type ion mobility spectrometer at one indoor site in central Bristol, UK, and one indoor and one outdoor site in a semirural area. We assess the diurnal variation in ion concentration and mobility, variability with meteorological parameters, and features within the ion mobility spectra. Ion concentration (typically in the range 100-1000 cm-3) was highest overnight and lowest in late morning and afternoon. Total conductivity also followed this trend suggesting that small ions contribute more to conductivity than larger charged particles, although at the semirural site, indoor activity produced charged aerosol intermittently, while infiltration of outdoor aerosol contributed at the urban site. Negative ion mobility (typically 1.6-1.9 cm2 V-1 s-1) was higher overnight than at other times, while positive ion mobility (typically 1.2-1.4 cm2 V-1 s-1) showed no diurnal variability. In general, temperature, pressure, wind speed, and water vapor pressure were inversely related to both concentration and mobility, except outdoors when (negative) mobility increased with increasing temperature and pressure, while increased relative humidity was associated with higher ion mobilities and concentrations. Analysis of high-resolution mobility spectra revealed several mobilities for each polarity at which peaks were identified across all sites, suggesting similarity in composition but with varying importance at each site. Intermediate ions (mobilities 0.2-0.3 cm2 V-1 s-1) were observed at the outdoor site, but individual nucleation events which may be associated with them were not identifiable.

  19. Dynamic determination of kinetic parameters, computer simulation, and probabilistic analysis of growth of Clostridium perfringens in cooked beef during cooling.

    PubMed

    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 <1logCFU/g, the residuals of predictions are <0.4logCFU/g. Overall, 74% of the residuals of predictions are <0.2logCFU/g, 7.7% are >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. PMID:25500276

  20. Effects of 10-week eccentric overload training on kinetic parameters during change of direction in football players.

    PubMed

    de Hoyo, Moisés; Sañudo, Borja; Carrasco, Luis; Mateo-Cortes, Jesús; Domínguez-Cobo, Sergio; Fernandes, Orlando; Del Ojo, Juan J; Gonzalo-Skok, Oliver

    2016-07-01

    The aim of the current study was to analyse the effect of 10-week eccentric overload training on kinetic parameters during change of direction (COD) in U-19 football players. The outcome measured included relative peak braking (rPB) and propulsive force (rPF), contact time (CT), time spent during braking (BT) and propulsive phase (PT), relative total (rTOT_IMP), braking (rB_IMP) and propulsive (rP_IMP) impulses. Between-group results showed a substantial better improvement (likely) in CT (ES: 0.72) and BT (ES: 0.74) during side-step cutting, and in rPB (ES: 0.84) and rB_IMP (ES: 0.72) during crossover cutting, in the experimental group (EXP) in comparison to control group (CON). Within-group analysis showed a substantially better performance (likely to almost certain) in CT (ES: 1.19), BT (ES: 1.24), PT (ES: 0.70), rPB (ES: 0.75), rPF (ES: 0.68), rTOT_IMP (ES: 0.48) and rB_IMP (ES: 0.50) in EXP during side-step cutting. Regarding crossover cutting, within-group analysis showed a substantial better performance (likely to almost certain) in CT (ES: 0.75), rPB (ES: 0.75), rPF (ES: 1.34), rTOT_IMP (ES: 0.61), rB_IMP (ES: 0.76) and rP_IMP (ES: 0.46) in EXP. In conclusion, the eccentric overload-based programme led to an improvement in kinetic parameters during COD football tasks. PMID:26963941

  1. Estimation of Hoffman-Lauritzen parameters from nonisothermal crystallization kinetics of PET/MWCNT nanocomposites

    NASA Astrophysics Data System (ADS)

    Gaonkar, Amita; Murudkar, Vrishali; Deshpande, V. D.

    2016-05-01

    Polyethylene terephthalate (PET) and Nucleated PET/ multi-walled carbon nanotubes (MWCNTs) nanocomposites with different MWCNTs loadings were prepared by melt compounding. The influence of the addition of MWCNTs and precipitated PET (p-PET) on the morphology and thermal properties of the nanocomposites was investigated. From Transmission Electronic Microscopy (TEM) and Wide angle X-Ray diffraction (WAXD) study, it can be clearly seen that nanocomposites with low MWCNTs contents (0.1 wt. %) get better MWCNTs dispersion than higher MWCNT loading. Comparing with PET, nucleated PET nanocomposite with 0.1% MWCNT loading shows higher value of Lauritzen-Hoffman parameters U* and Kg evaluated using the differential isoconversional method. Crystallization regime transition temperature range shifts to higher temperature (208°C - 215°C) for nanocomposites. The presence of p-PET in addition of MWCNT, which act as good nucleating agent, enhanced the crystallization of PET through heterogeneous nucleation.

  2. Antioxidative effects of melatonin on kinetics, microscopic and oxidative parameters of cryopreserved bull spermatozoa.

    PubMed

    Ashrafi, Iraj; Kohram, Hamid; Ardabili, Farhad Farrokhi

    2013-06-01

    Reactive oxygen species generated during the freeze-thawing process may reduce sperm quality. This study evaluates the effects of melatonin supplementation as an antioxidant in the semen extender on post-thaw parameters of bull spermatozoa. Melatonin was added to the citrate-egg yolk extender to yield six different final concentrations: 0, 0.1, 1, 2, 3 and 4mM. Ejaculates were collected from six proven Holstein bulls. Semen was diluted in the extender packaged in straws, which was frozen with liquid nitrogen. The semen extender supplemented with various doses of melatonin increased (p<0.05) total motility, progressive motility, linearity, sperm track straightness, lateral head displacement, viability, integrity of the sperm membrane and total normal morphology of sperm after the freeze-thawing process. The most effective concentration of melatonin in microscopic evaluations of the bull sperm freezing extender was 2mM. The highest (p<0.05) value of total antioxidant capacity (48.9±2.7) and the lowest value of lipid peroxidation (2.7±0.8) were achieved by inclusion of 3mM concentration of melatonin in the semen extender and the highest activity of catalase (0.7±0.1) was obtained by 2mM melatonin. Four millimolar concentration of melatonin were reduced (p<0.05) the progressive motility and straight linear velocity. In conclusion, supplementation of 2 or 3mM concentration of melatonin in the semen extender improved the quality of post-thawed semen, which may associate with a reduction in lipid peroxidation as well as an increase in the total antioxidant capacity and antioxidant enzyme activity. PMID:23664651

  3. Impacts of meteorological parameters and emissions on decadal and interannual variations of black carbon in China for 1980-2010

    NASA Astrophysics Data System (ADS)

    Mao, Yu-Hao; Liao, Hong; Han, Yongming; Cao, Junji

    2016-02-01

    We quantified the impacts of variations in meteorological parameters and emissions on decadal trends and interannual variations of black carbon (BC) in China for 1980-2010 using a global chemical transport model (GEOS-Chem) driven by the Modern Era Retrospective-analysis for Research and Applications meteorological fields. Model results reasonably captured the decadal and interannual variations of observed BC in China. From 1980 to 2010, simulated surface concentrations and tropospheric column burdens of BC increased by 0.21 µg m-3 (29%) and by 0.29 mg m-2 (37%), respectively, averaged over China; the corresponding all-sky direct radiative forcing at the top of the atmosphere increased by 0.35 W m-2 (51%). Considering variations in both meteorological parameters and emissions for 1980-2010, simulated annual mean surface concentrations (column burdens) of BC were in the range of 0.7-1.0 µg m-3 (0.8-1.1 mg m-2) averaged over China. The associated decadal trends were 0.31 µg m-3 decade-1 (0.29 mg m-2 decade-1) in the 1980s, -0.20 (-0.10) in the 1990s, and 0.16 (0.21) in the 2000s. The interannual variations were -20% to 15% (-20% to 11%) for deviation from the mean, 0.068 µg m-3 (0.069 mg m-2) for mean absolute deviation, and 7.7% (7.1%) for absolute percent departure from the mean. Model sensitivity simulations indicated that the decadal trends of surface concentrations and column burdens of BC were mainly driven by changes in emissions, while the interannual variations were dependent on variations of both meteorological parameters and emissions.

  4. Thermodynamics and kinetics parameters of co-combustion between sewage sludge and water hyacinth in CO2/O2 atmosphere as biomass to solid biofuel.

    PubMed

    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. PMID:27416513

  5. Estimation of turbulent kinetic energy using 4D phase-contrast MRI: Effect of scan parameters and target vessel size.

    PubMed

    Ha, Hojin; Hwang, Dongha; Kim, Guk Bae; Kweon, Jihoon; Lee, Sang Joon; Baek, Jehyun; Kim, Young-Hak; Kim, Namkug; Yang, Dong Hyun

    2016-07-01

    Quantifying turbulence velocity fluctuation is important because it indicates the fluid energy dissipation of the blood flow, which is closely related to the pressure drop along the blood vessel. This study aims to evaluate the effects of scan parameters and the target vessel size of 4D phase-contrast (PC)-MRI on quantification of turbulent kinetic energy (TKE). Comprehensive 4D PC-MRI measurements with various velocity-encoding (VENC), echo time (TE), and voxel size values were carried out to estimate TKE distribution in stenotic flow. The total TKE (TKEsum), maximum TKE (TKEmax), and background noise level (TKEnoise) were compared for each scan parameter. The feasibility of TKE estimation in small vessels was also investigated. Results show that the optimum VENC for stenotic flow with a peak velocity of 125cm/s was 70cm/s. Higher VENC values overestimated the TKEsum by up to six-fold due to increased TKEnoise, whereas lower VENC values (30cm/s) underestimated it by 57.1%. TE and voxel size did not significantly influence the TKEsum and TKEnoise, although the TKEmax significantly increased as the voxel size increased. TKE quantification in small-sized vessels (3-5-mm diameter) was feasible unless high-velocity turbulence caused severe phase dispersion in the reference image. PMID:26968139

  6. Computer-based gait analysis of dogs: evaluation of kinetic and kinematic parameters after cemented and cementless total hip replacement.

    PubMed

    Drüen, S; Böddeker, J; Meyer-Lindenberg, A; Fehr, M; Nolte, I; Wefstaedt, P

    2012-01-01

    To date it is unclear whether cementless total hip replacement (THR) in dogs is of clinical advantage in comparison to cemented THR with regard to lameness improvement. Thus the aim of this study was to compare objectively the development of the gait pattern after cemented and cementless THR in dogs. For this purpose, 18 adult dogs with hip dysplasia underwent computer-based gait analysis on an instrumented treadmill prior to unilateral THR and then again ten days, four weeks and four months after surgery. Analysed kinetic parameters were symmetry indices (SI) of vertical ground reaction forces (GRF), which included peak vertical forces (PFz), mean vertical forces (MFz), vertical impulse (IFz), and vertical ground reaction forces of the arthroplasty limbs only. Analysed kinematic parameters were range-of-motion and the flexion and extension angles of hip, stifle and hock joints. The symmetry indice for PVF, MFz and IFz decreased to a value less than six in both THR groups four months after surgery, which is defined as not lame. Improvement in lameness of the arthroplasty limbs during the examination period of four months was not significantly different between the cemented and cementless groups. The results suggest that within a short-term observation period of four months after surgery, neither cementless nor cemented THR have a greater advantage with regard to lameness improvement. Additional studies with larger pools of subjects and longer time periods for follow-up examinations are necessary to verify these findings. PMID:22828804

  7. Contribution of counterions and degree of ionization for birefringence creation and relaxation kinetics parameters of PAH/PAZO films

    SciTech Connect

    Raposo, Maria Monteiro Timóteo, Ana Rita; Ribeiro, Paulo A.; Ferreira, Quirina; Botelho do Rego, Ana Maria

    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.

  8. Final Report for NFE-07-00912: Development of Model Fuels Experimental Engine Data Base & Kinetic Modeling Parameter Sets

    SciTech Connect

    Bunting, Bruce G

    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).

  9. Determination of bacterial and viral transport parameters in a gravel aquifer assuming linear kinetic sorption and desorption

    NASA Astrophysics Data System (ADS)

    Mallén, G.; Maloszewski, P.; Flynn, R.; Rossi, P.; Engel, M.; Seiler, K.-P.

    2005-05-01

    The bacteria Escherichia coli and Pseudomonas putida, and the bacteriophage virus H40/1 are examined both for their transport behaviour relative to inert solute tracers and for their modelability under natural flow conditions in a gravel aquifer. The microbes are attenuated in the following sequence: H40/1≥ P. putida≫ E. coli. The latter is desorbed almost completely within a few days. Breakthrough and recovery curves of the simultaneously injected non-reactive tracers are simulated with the 2D and 1D dispersion equation, in order to ascertain longitudinal dispersivity ( αL) and mean flow time ( T0). Mathematical modelling is difficult due to the aquifer heterogeneity, which results in preferential flow paths between injection and observation wells. Therefore, any attempt of fitting the dispersion model (DM) to the entire inert-tracer breakthrough curve (BTC) fails. Adequate fitting of the model to measured data only succeeds using a DM consisting of a superposition of several BTCs, each representing another set of flow paths. This gives rise to a multimodal, rather than a Gaussian groundwater velocity distribution. Only hydraulic parameters derived from the fastest partial curve, which is fitted to the rising part of the Uranine BTC, are suitable to model microbial breakthroughs. The hydraulic parameters found using 2D and 1D models were nearly identical. Their values were put into an analytical solution of 1D advective-dispersive transport combined with two-site reaction model introduced by Cameron and Klute [Cameron, D.R., Klute, A., 1977. Convective-dispersive solute transport with a combined equilibrium and kinetic adsorption model. Water Resour. Res. 13, 183-189], in order to identify reactive transport parameters (sorption/desorption) and attenuation mechanisms for the microbes migration. This shows that the microbes are almost entirely transported through preferential flow paths, which are represented by the first partial curve. Inert tracers, however

  10. Evaluation of Interindividual Human Variation in Bioactivation and DNA Adduct Formation of Estragole in Liver Predicted by Physiologically Based Kinetic/Dynamic and Monte Carlo Modeling.

    PubMed

    Punt, Ans; Paini, Alicia; Spenkelink, Albertus; Scholz, Gabriele; Schilter, Benoit; van Bladeren, Peter J; Rietjens, Ivonne M C M

    2016-04-18

    Estragole is a known hepatocarcinogen in rodents at high doses following metabolic conversion to the DNA-reactive metabolite 1'-sulfooxyestragole. The aim of the present study was to model possible levels of DNA adduct formation in (individual) humans upon exposure to estragole. This was done by extending a previously defined PBK model for estragole in humans to include (i) new data on interindividual variation in the kinetics for the major PBK model parameters influencing the formation of 1'-sulfooxyestragole, (ii) an equation describing the relationship between 1'-sulfooxyestragole and DNA adduct formation, (iii) Monte Carlo modeling to simulate interindividual human variation in DNA adduct formation in the population, and (iv) a comparison of the predictions made to human data on DNA adduct formation for the related alkenylbenzene methyleugenol. Adequate model predictions could be made, with the predicted DNA adduct levels at the estimated daily intake of estragole of 0.01 mg/kg bw ranging between 1.6 and 8.8 adducts in 10(8) nucleotides (nts) (50th and 99th percentiles, respectively). This is somewhat lower than values reported in the literature for the related alkenylbenzene methyleugenol in surgical human liver samples. The predicted levels seem to be below DNA adduct levels that are linked with tumor formation by alkenylbenzenes in rodents, which were estimated to amount to 188-500 adducts per 10(8) nts at the BMD10 values of estragole and methyleugenol. Although this does not seem to point to a significant health concern for human dietary exposure, drawing firm conclusions may have to await further validation of the model's predictions. PMID:26952143

  11. Impacts of Meteorological Parameters and Emissions on Decadal and Interannual Variations of Black Carbon in China for 1980-2010

    NASA Astrophysics Data System (ADS)

    Mao, Y.; Liao, H.

    2015-12-01

    We quantified the impacts of variations in meteorological parameters and emissions on the decadal and interannual variations of surface black carbon (BC) concentrations in China for a 31-yr period (1980-2010) using a global chemical transport model (GEOS-Chem) driven by the MERRA meteorological fields. Relative to year 1980, simulated surface BC concentrations in year 2010 increased by 0.21 µg m-3 (29%) averaged over China. The corresponding all-sky direct radiative forcing of BC at the top of the atmosphere increased by 0.35 W m-2 (51%). Considering variations in both meteorological parameters and emissions for 1980-2010, simulated annual mean surface BC concentrations averaged over China were in the range of ~0.7-1.0 µg m-3 and showed decadal trends of 0.31, -0.20, 0.16 µg m-3 decade-1, respectively, in the 1980s, 1990s, and 2000s. The associated interannual variations were -20 to 15%, 0.068 µg m-3, and 7.7%, respectively, for the values of deviation from the mean, mean absolute deviation, and absolute percent departure from the mean. Model sensitivity simulations indicated that the decadal trends of surface BC concentrations were mainly driven by changes in emissions, while the interannual variations were dependent on variations of both emissions and meteorological parameters. We also found that the strength of the East Asian monsoon (either summer or winter monsoon) negatively correlated with surface BC concentrations in eastern China (20-45° N, 110-125° E) (r = -0.7), mainly by the changes in atmospheric circulation. Relative to the five strongest monsoon years, simulated surface BC concentrations over eastern China were higher by 2-10% in the five weakest monsoon years.

  12. Bifurcations, chaos, and sensitivity to parameter variations in the Sato cardiac cell model

    NASA Astrophysics Data System (ADS)

    Otte, Stefan; Berg, Sebastian; Luther, Stefan; Parlitz, Ulrich

    2016-08-01

    The dynamics of a detailed ionic cardiac cell model proposed by Sato et al. (2009) is investigated in terms of periodic and chaotic action potentials, bifurcation scenarios, and coexistence of attractors. Starting from the model's standard parameter values bifurcation diagrams are computed to evaluate the model's robustness with respect to (small) parameter changes. While for some parameters the dynamics turns out to be practically independent from their values, even minor changes of other parameters have a very strong impact and cause qualitative changes due to bifurcations or transitions to coexisting attractors. Implications of this lack of robustness are discussed.

  13. Platelet membrane variations and their effects on δ-granule secretion kinetics and aggregation spreading among different species.

    PubMed

    Gruba, Sarah M; Koseoglu, Secil; Meyer, Audrey F; Meyer, Ben M; Maurer-Jones, Melissa A; Haynes, Christy L

    2015-07-01

    Platelet exocytosis is regulated partially by the granular/cellular membrane lipids and proteins. Some platelets contain a membrane-bound tube, called an open canalicular system (OCS), which assists in granular release events and increases the membrane surface area for greater spreading. The OCS is not found in all species, and variations in membrane composition can cause changes in platelet secretion. Since platelet studies use various animal models, it is important to understand how platelets differ in both their composition and granular release to draw conclusions among various models. The relative phospholipid composition of the platelets with (mouse, rabbit) and without (cow) an OCS was quantified using UPLC-MS/MS. Cholesterol and protein composition was measured using an Amplex Red Assay and BCA Assay. TEM and dark field platelet images were gathered and analyzed with Image J. Granular release was monitored with single cell carbon fiber microelectrode amperometry. Cow platelets contained greater amounts of cholesterol and sphingomyelin. In addition, they yield greater serotonin release and longer δ granule secretion times. Finally, they showed greater spreading area with a greater range of spread. Platelets containing an OCS had more similarities in their membrane composition and secretion kinetics compared to cow platelets. However, cow platelets showed greater fusion pore stability which could be due to extra sphingomyelin and cholesterol, the primary components of lipid rafts. In addition, their greater stability may lead to many granules assisting in spreading. This study highlights fundamental membrane differences and their effects on platelet secretion. PMID:25906946

  14. TU-C-12A-11: Comparisons Between Cu-ATSM PET and DCE-CT Kinetic Parameters in Canine Sinonasal Tumors

    SciTech Connect

    La Fontaine, M; Bradshaw, T; Kubicek, L; Forrest, L; Jeraj, R

    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

  15. Measurement of diurnal and semidiurnal rotational variations and tidal parameters of Earth

    NASA Technical Reports Server (NTRS)

    Herring, Thomas A.; Dong, Danan

    1994-01-01

    We discuss the determination of diurnal and semidiurnal variations in the rotation rate and the direction of rotation axis of Earth from the analysis of 8 years of very long baseline interferometry (VLBI) data. This analysis clearly show that these variations are largely periodic and tidally driven; that is, the periods of the variations correspond to the periods of the largest lunar and solar tides. For rotation rate variations, expressed in terms of changes in universal time (UT), the tidal lines with the largest observed signals are O1 (amplitude 23.5 microseconds in time (microseconds), period 25.82 solar hours); KL (18.9 microseconds, 23.93 hours); M2 (17.9 microseconds, 12.54 hours); and S2 (8.6 microseconds, 12.00 hours). For variations in the direction of the rotation axis (polar motion), significant signals exist in the retrograde semidiurnal band at the M2 and S2 tides (amplitudes 265 and 119 microarc seconds (microarc seconds, respectively); the prograde diurnal band at the O1, K1, and P1 tides (amplitudes 199, 152, and 60 microarc seconds, respectively); and the prograde semidiurnal band at the M2 and K2 tides (amplitudes 58 and 39 microarc seconds, respectively). Variations in the retrograde diurnal band are represented by corrections with previous estimates except that a previously noted discrepancy in the 13.66-day nutation (corresponding to the O1 tide) is largely removed in this new analysis. We estimate that the standard deviations of these estimates are 1.0 microseconds for the UT1 variations and 14-16 microarc seconds for the polar motion terms. These uncertainties correspond to surface displacements of approximately 0.5 mm. From the analysis of atmospheric angular momentum data we conclude that variations in UT1 excited by the atmosphere with subdaily periods are small (approximately 1 microsecond). We find that the average radial tidal displacements of the VLBI sites in the diurnal band are largely consistent with known deficiencies in current

  16. FAST TRACK COMMUNICATION Accurate estimate of α variation and isotope shift parameters in Na and Mg+

    NASA Astrophysics Data System (ADS)

    Sahoo, B. K.

    2010-12-01

    We present accurate calculations of fine-structure constant variation coefficients and isotope shifts in Na and Mg+ using the relativistic coupled-cluster method. In our approach, we are able to discover the roles of various correlation effects explicitly to all orders in these calculations. Most of the results, especially for the excited states, are reported for the first time. It is possible to ascertain suitable anchor and probe lines for the studies of possible variation in the fine-structure constant by using the above results in the considered systems.

  17. Impact of seasonal variation, age and smoking status on human semen parameters: The Massachusetts General Hospital experience

    PubMed Central

    Chen, Zuying; Godfrey-Bailey, Linda; Schiff, Isaac; Hauser, Russ

    2004-01-01

    Background To investigate the relationship of human semen parameters with season, age and smoking status. Methods The present study used data from subjects recruited into an ongoing cross-sectional study on the relationship between environmental agents and semen characteristics. Our population consisted of 306 patients who presented to the Vincent Memorial Andrology Laboratory of Massachusetts General Hospital for semen evaluation. Sperm concentration and motility were measured with computer aided sperm analysis (CASA). Sperm morphology was scored using Tygerberg Kruger strict criteria. Regression analyses were used to investigate the relationships between semen parameters and season, age and smoking status, adjusting for abstinence interval. Results Sperm concentration in the spring was significantly higher than in winter, fall and summer (p < 0.05). There was suggestive evidence of higher sperm motility and percent of sperm with normal morphology in the spring than in the other seasons. There were no statistically significant relationships between semen parameters and smoking status, though current smokers tended to have lower sperm concentration. We also did not find a statistically significant relationship between age and semen parameters. Conclusions We found seasonal variations in sperm concentration and suggestive evidence of seasonal variation in sperm motility and percent sperm with normal morphology. Although smoking status was not a significant predictor of semen parameters, this may have been due to the small number of current smokers in the study. PMID:15507127

  18. Electrical Characterization of 4H-SiC JFET Wafer: DC Parameter Variations for Extreme Temperature IC Design

    NASA Technical Reports Server (NTRS)

    Neudeck, Philip G.; Chen, Liangyu; Spry, David J.; Beheim, Glenn M.; Chang, Carl W.

    2014-01-01

    This work reports DC electrical characterization of a 76 mm diameter 4H-SiC JFET test wafer fabricated as part of NASA's on-going efforts to realize medium-scale ICs with prolonged and stable circuit operation at temperatures as high as 500 degC. In particular, these measurements provide quantitative parameter ranges for use in JFET IC design and simulation. Larger than expected parameter variations were observed both as a function of position across the wafer as well as a function of ambient testing temperature from 23 degC to 500 degC.

  19. Sensitivity of the stability of a waste emplacement drift to variation in assumed rock joint parameters in welded tuff

    SciTech Connect

    Christianson, M.

    1989-04-01

    This report presents the results of a numerical analysis to determine the effects of variation of rock joint parameters on stability of waste disposal rooms for vertical emplacement. Conditions and parameters used were taken from the Nevada Nuclear Waste Storage Investigation (NNWSI) Project Site Characterization Plan Conceptual Design report (MacDougall et al., 1987). Mechanical results are presented which illustrate the predicted distribution of stress, joint slip, and room deformations for times of initial excavation and after 50 years heating. 82 refs., 93 figs.

  20. Effect of Simultaneous Inoculation with Yeast and Bacteria on Fermentation Kinetics and Key Wine Parameters of Cool-Climate Chardonnay

    PubMed Central

    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. PMID:16391046

  1. Lacustrin magnetic parameters reveal the last 3,000 years environmental variation of the Ilan Plain, northeastern Taiwan

    NASA Astrophysics Data System (ADS)

    Huang, Yin-Sheng; Lee, Teh-Quei

    2015-04-01

    We discuss the paleo-environmental variation of the Ilan Plain in northeastern Taiwan for the last 3,000 years by using lacustrine magnetic records obtained from Meihua Lake (the MHL-5A core; 24° 38.58' N, 121° 43.96' E) and Longtan Lake (the LTL-9C core; 24° 47.70' N, 121° 44.40' E). The magnetic parameters analyzed in the study include magnetic susceptibility (χ), SIRM (saturated isothermal remnant magnetization), ARM (anhysteretic remnant magnetization), ARM/χ, and ARM/SIRM. The most notable feature in the magnetic records of both cores is an anomaly appeared at ~1,800 years. In the MHL-5A core, the parameters representing magnetic abundance variation (χ, SIRM, and ARM) are relatively higher before ~1,800 years and become lower after the time. On the contrary, the magnetic abundance parameters are lower before ~1,800 years but become higher after the time in the LTL-9C core. Besides, for the last ~700 years, the magnetic parameters in the MHL-5A core show a clear period variation. Also in the LTL-9C core, this period variation could be observed though the period is relatively ambiguous. Moreover, the magnetic grain size parameter ARM/SIRM shows that the grain size of magnetic minerals in both cores became finer gradually for the last ~3,000 years. The reason could be preliminary deduced: The Ilan Plain is a flooding plain and the main river in the plain is a braided river, the Lanyang River. Before ~1,800 years, the channel of the Lanyang River should be in the south of the plain (closer to the Meihua Lake). More sediment was brought into the lake by the flooding of the Lanyang River. After ~1,800 years, the channel of the Lanyang River shifted northward (closer to the Longtan Lake), and therefore the input to the Longtan Lake from the flooding might increase. The period variation after ~700 years could be roughly attributed to the rainfall effect. That is, precipitation variation resulting from the influence of the monsoon system might become significant

  2. Study of kinetic parameters and development of a voltammetric sensor for the determination of butylated hydroxyanisole (BHA) in oil samples.

    PubMed

    Thomas, Divya; Rasheed, Zafna; Jagan, Jesny Siri; Kumar, Krishnapillai Girish

    2015-10-01

    Electrochemical behavior of artificial antioxidant, butylated hydroxyanisole (BHA), was investigated at a glassy carbon electrode modified with poly L- cysteine [poly (L- Cys/GCE)]. BHA exhibits a pair of well - defined redox peak on L- cysteine modified GCE with Epa = 69 mV and Epc = 4 mV. The modified electrode showed good electrocatalytic activity towards the oxidation of BHA under optimal conditions and exhibited a linear response in the range from 1.0 × 10(-5) to 1.0 × 10(-6) M with a correlation coefficient of 0.998. The limit of detection was found to be 4.1 × 10(-7) M. The kinetics parameters of the proposed sensor such as heterogeneous electron transfer rate, k s , and charge transfer coefficient,α, was calculated and found to be 1.20 s(-1) and 0.575 respectively. The average surface concentration of BHA on the surface of poly (L- Cys/GCE) was calculated to be 3.18 × 10(-4) mol cm(-2). The analytical utility of the proposed sensor was evaluated by the successful determination of BHA in coconut oil and sesame oil samples. PMID:26396421

  3. Net thrust calculation sensitivity of an afterburning turbofan engine to variations in input parameters

    NASA Technical Reports Server (NTRS)

    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.

  4. Variations in environmental tritium doses due to meteorological data averaging and uncertainties in pathway model parameters

    SciTech Connect

    Kock, A.

    1996-05-01

    The objectives of this research are: (1) to calculate and compare off site doses from atmospheric tritium releases at the Savannah River Site using monthly versus 5 year meteorological data and annual source terms, including additional seasonal and site specific parameters not included in present annual assessments; and (2) to calculate the range of the above dose estimates based on distributions in model parameters given by uncertainty estimates found in the literature. Consideration will be given to the sensitivity of parameters given in former studies.

  5. Influence of Analogy Instruction for Pitch Variation on Perceptual Ratings of Other Speech Parameters

    ERIC Educational Resources Information Center

    Tse, Andy C. Y.; Wong, Andus W-K.; Ma, Estella P-M.; Whitehill, Tara L.; Masters, Rich S. W.

    2013-01-01

    Purpose: "Analogy" is the similarity of different concepts on which a comparison can be based. Recently, an analogy of "waves at sea" was shown to be effective in modulating fundamental frequency (F[subscript 0]) variation. Perceptions of intonation were not examined, as the primary aim of the work was to determine whether…

  6. SENSITIVITY OF A REGIONAL OXIDANT MODEL TO VARIATIONS IN CLIMATE PARAMETERS, VOLUME I AND II

    EPA Science Inventory

    In order to investigate the sensitivity of ozone concentrations to future climate variations, a regional oxidant model was applied for future climate scenarios to two regions: one covering central California (San Joaquin Valley, Sierra Nevada mountains and the San Francisco Bay A...

  7. Diurnal and seasonal variations of carbonate system parameters on Luhuitou fringing reef, Sanya Bay, Hainan Island, South China Sea

    NASA Astrophysics Data System (ADS)

    Zhang, Chenglong; Huang, Hui; Ye, Cheng; Huang, Liangmin; Li, Xiubao; Lian, Jiansheng; Liu, Sheng

    2013-11-01

    The 3-day diurnal dynamics of carbonate system and related parameters on Luhuitou fringing reef of Sanya Bay-adjacent to the South China Sea (SCS) were observed in December of 2009 (early winter), April (spring), July (summer) and November (late-autumn) of 2010. The Luhuitou fringing reef ecosystem was generally dominated by macro and planktonic algae throughout the year except by coralline algae in winter. The system parameters showed distinct diurnal trends in the four seasons. Averaged ranges of diurnal variation for dissolved oxygen and partial pressure of CO2 (pCO2) were higher in the autumn, 4.67mgL-1 and 218.2μatm, respectively than other seasons. Averaged ranges of diurnal variation for normalized total alkalinity (NTA) was higher in the winter (61.3μmolkg-1), and lower in the spring (16.0μmolkg-1). The diurnal variations are mainly controlled by biological activities, especially by the processes of photosynthesis and respiration in the reef ecosystem. In winter, however, calcification and dissolution contributed more to the diurnal variations, compared with the other three seasons. Total alkalinity was largely related to seasonal changes in river inflow rates. Dissolved oxygen, pH, total CO2 and aragonite saturation also showed seasonal variations. These variations were mainly controlled by the seasonal changes of photosynthesis and respiration, which were mainly affected by changes in benthic community structure, temperature and river inflow rates. The oversaturated pCO2 in the reef ecosystem with respect to the atmosphere in the winter and summer resulted in CO2 discharge from the reef ecosystem to the SCS. The whole system served as net source of CO2 to the atmosphere and the adjacent South China Sea on an annual time scale.

  8. Inverse Kinetics

    Energy Science and Technology Software Center (ESTSC)

    2000-03-20

    Given the space-independent, one energy group reactor kinetics equations and the initial conditions, this prgram determines the time variation of reactivity required to produce the given input of flux-time data.

  9. Seasonal variations of androgens and of several sexual parameters in male Meriones shawi in southern Morocco.

    PubMed

    Zaime, A; Laraki, M; Gautier, J Y; Garnier, D H

    1992-05-01

    Seasonal changes of several parameters related to sexual activity were studied in the gerbil (Rodentia: Gerbillidae). The weight of the testes, seminal vesicles, and adrenals fluctuate throughout the year. Plasma androgen levels and histological aspect of the testes also vary throughout the year. Spermatogonial and steroid activities are synchronous and are maximal in winter and spring. The relationship between these activities and environmental climatic parameters is discussed: the beginning of sexual activity seems correlated with the first rains. PMID:1601278

  10. Variation of Solar, Interplanetary and Geomagnetic Parameters during Solar Cycles 21-24

    NASA Astrophysics Data System (ADS)

    Oh, Suyeon; Kim, Bogyeong

    2013-06-01

    The length of solar cycle 23 has been prolonged up to about 13 years. Many studies have speculated that the solar cycle 23/24 minimum will indicate the onset of a grand minimum of solar activity, such as the Maunder Minimum. We check the trends of solar (sunspot number, solar magnetic fields, total solar irradiance, solar radio flux, and frequency of solar X-ray flare), interplanetary (interplanetary magnetic field, solar wind and galactic cosmic ray intensity), and geomagnetic (Ap index) parameters (SIG parameters) during solar cycles 21-24. Most SIG parameters during the period of the solar cycle 23/24 minimum have remarkably low values. Since the 1970s, the space environment has been monitored by ground observatories and satellites. Such prevalently low values of SIG parameters have never been seen. We suggest that these unprecedented conditions of SIG parameters originate from the weakened solar magnetic fields. Meanwhile, the deep 23/24 solar cycle minimum might be the portent of a grand minimum in which the global mean temperature of the lower atmosphere is as low as in the period of Dalton or Maunder minimum.

  11. Four-order stiffness variation of laser-fabricated photopolymer biodegradable scaffolds by laser parameter modulation.

    PubMed

    Farkas, Balázs; Romano, Ilaria; Ceseracciu, Luca; Diaspro, Alberto; Brandi, Fernando; Beke, Szabolcs

    2015-10-01

    The effects of various fabrication parameters of our Mask Projection Excimer Laser StereoLithography (MPExSL) system were investigated. We demonstrate that laser parameters directly change the physical properties (stiffness, thermal degradation, and height/thickness) of the poly(propylene fumarate) (PFF) scaffold structures. The tested parameters were the number of pulses, fluence per pulse and laser repetition rate. We present a four-order tuning capability of MPExSL-fabricated structures' stiffness without altering the resin composition or using cumbersome post-treatment procedures. Thermogravimetric analysis and differential scanning calorimetry confirmed this tuning capability. Prototype-segmented scaffold designs are presented and analyzed to further expand the concept and exploit this in situ stiffness tuning capability of the scaffolds for tissue engineering and regenerative medicine applications. PMID:26117734

  12. Variation of plasma parameters of vacuum arc column with gap distance

    NASA Astrophysics Data System (ADS)

    Han, Wen; Yuan, Zhao; He, Junjia

    2016-07-01

    On the basis of a two-dimensional (2D) magneto-hydrodynamic model, we studied long-gap-distance vacuum arcs in a uniform axial magnetic field and determined the effect of gap distance varying in a large range on plasma parameters. Simulation results showed that with increasing gap distance, the parameters of the plasma near the cathode are almost invariant, except for ion number density, but the parameters of the plasma in front of the anode clearly vary; meanwhile, joule heat gradually becomes the main source of energy for the arc column. In a short gap, a clear current constriction can be found in the entire arc column. Whereas when the gap distance exceeds a certain value, a sharp contraction of the current only arises in front of the anode.

  13. Solar cycle variation of the statistical distribution of the solar wind ɛ parameter and its constituent variables

    NASA Astrophysics Data System (ADS)

    Tindale, E.; Chapman, S. C.

    2016-06-01

    We use 20 years of Wind solar wind observations to investigate the solar cycle variation of the solar wind driving of the magnetosphere. For the first time, we use generalized quantile-quantile plots to compare the statistical distribution of four commonly used solar wind coupling parameters, Poynting flux, B2, the ɛ parameter, and vB, between the maxima and minima of solar cycles 23 and 24. We find the distribution is multicomponent and has the same functional form at all solar cycle phases; the change in distribution is captured by a simple transformation of variables for each component. The ɛ parameter is less sensitive than its constituent variables to changes in the distribution of extreme values between successive solar maxima. The quiet minimum of cycle 23 manifests only in lower extreme values, while cycle 24 was less active across the full distribution range.

  14. Variation of Jupiter's aurora observed by Hisaki/EXCEED: 2. Estimations of auroral parameters and magnetospheric dynamics

    NASA Astrophysics Data System (ADS)

    Tao, Chihiro; Kimura, Tomoki; Badman, Sarah V.; André, Nicolas; Tsuchiya, Fuminori; Murakami, Go; Yoshioka, Kazuo; Yoshikawa, Ichiro; Yamazaki, Atsushi; Fujimoto, Masaki

    2016-05-01

    Jupiter's auroral parameters are estimated from observations by a spectrometer EXCEED (Extreme Ultraviolet Spectroscope for Exospheric Dynamics) on board Japanese Aerospace Exploration Agency's Earth-orbiting planetary space telescope Hisaki. EXCEED provides continuous auroral spectra covering the wavelength range over 80-148 nm from the whole northern polar region. The auroral electron energy is estimated using a hydrocarbon color ratio adopted for the wavelength range of EXCEED, and the emission power in the long wavelength range 138.5-144.8 nm is used as an indicator of total emitted power before hydrocarbon absorption and auroral electron energy flux. The quasi-continuous observations by Hisaki provide the auroral electron parameters and their relation under different auroral activity levels. Short- (within < one planetary rotation) and long-term (> one planetary rotation) enhancements of auroral power accompany increases of the electron number flux rather than the electron energy variations. The relationships between the auroral electron energy (~70-400 keV) and flux (1026-1027/s, 0.08-0.9 μA/m2) estimated from the observations over a 40 day interval are in agreement with field-aligned acceleration theory when incorporating probable magnetospheric parameters. Applying the electron acceleration theory to each observation point, we explore the magnetospheric source plasma variation during these power-enhanced events. Possible scenarios to explain the derived variations are (i) an adiabatic variation of the magnetospheric plasma under a magnetospheric compression and/or plasma injection, and (ii) a change of the dominant auroral component from the main emission (main aurora) to the emission at the open-closed boundary.

  15. A coupled transport and solid mechanics formulation with improved reaction kinetics parameters for modeling oxidation and decomposition in a uranium hydride bed.

    SciTech Connect

    Salloum, Maher N.; Shugard, Andrew D.; Kanouff, Michael P.; Gharagozloo, Patricia E.

    2013-03-01

    Modeling of reacting flows in porous media has become particularly important with the increased interest in hydrogen solid-storage beds. An advanced type of storage bed has been proposed that utilizes oxidation of uranium hydride to heat and decompose the hydride, releasing the hydrogen. To reduce the cost and time required to develop these systems experimentally, a valid computational model is required that simulates the reaction of uranium hydride and oxygen gas in a hydrogen storage bed using multiphysics finite element modeling. This SAND report discusses the advancements made in FY12 (since our last SAND report SAND2011-6939) to the model developed as a part of an ASC-P&EM project to address the shortcomings of the previous model. The model considers chemical reactions, heat transport, and mass transport within a hydride bed. Previously, the time-varying permeability and porosity were considered uniform. This led to discrepancies between the simulated results and experimental measurements. In this work, the effects of non-uniform changes in permeability and porosity due to phase and thermal expansion are accounted for. These expansions result in mechanical stresses that lead to bed deformation. To describe this, a simplified solid mechanics model for the local variation of permeability and porosity as a function of the local bed deformation is developed. By using this solid mechanics model, the agreement between our reacting bed model and the experimental data is improved. Additionally, more accurate uranium hydride oxidation kinetics parameters are obtained by fitting the experimental results from a pure uranium hydride oxidation measurement to the ones obtained from the coupled transport-solid mechanics model. Finally, the coupled transport-solid mechanics model governing equations and boundary conditions are summarized and recommendations are made for further development of ARIA and other Sandia codes in order for them to sufficiently implement the model.

  16. The effects of the variations of turbulence parameters on the observable turbulence statistics

    NASA Astrophysics Data System (ADS)

    Ding, S. Y.

    2016-06-01

    In order to study how the statistical properties of the observational quantities of the turbulent molecular cloud models vary with different turbulence parameters, I use the artificially generated random numerical models based on Gaussian fields created by the code PYFC with different values of the 1D density Fourier spectral index βn, the turbulence driving parameter, i.e. the b parameter and the 1D Fourier velocity power spectral index βv. Then I calculate the line profiles of 13CO emission on every sight line. I derive the statistical properties of column density N, line intensity W, peak intensity Tpeak and velocity dispersion Vrms on every sight line. I discover that as βn increases, (1) the standard deviations σln (N/) and σln (W/) of the logarithmic column density ln (N/) and the logarithmic integrated intensity ln (W/) increase; (2) the number of the low Tpeak values becomes larger; (3) the probability distribution function (PDF) of Vrms inclines to left a little. As the b parameter increases, (1) the values of both σln (N/) and σln (W/) increase; (2) the numbers of both the low Tpeak values and the saturated Tpeak values become larger; (3) the PDF of Vrms inclines to left obviously. As βv increases, (1) the PDF of ln (W/) remains generally unchanged; (2) the PDF of Tpeak remains generally unchanged; (3) the PDF of Vrms inclines to left obviously. I also discuss the relationship among σN/, Mach number, the b parameter and βn.

  17. Neutron diffraction measurements and micromechanical modelling of temperature-dependent variations in TATB lattice parameters

    DOE PAGESBeta

    Yeager, John D.; Luscher, Darby J.; Vogel, Sven C.; Clausen, Bjorn; Brown, Donald W.

    2016-06-01

    Triaminotrinitrobenzene (TATB) is a highly anisotropic molecular crystal used in several plastic-bonded explosive (PBX) formulations. TATB-based explosives exhibit irreversible volume expansion (“ratchet growth”) when thermally cycled. A theoretical understanding of the relationship between anisotropy of the crystal, crystal orientation distribution (texture) of polycrystalline aggregates, and the intergranular interactions leading to this irreversible growth is necessary to accurately develop physics-based predictive models for TATB-based PBXs under various thermal environments. In this work, TATB lattice parameters were measured using neutron diffraction during thermal cycling of loose powder and a pressed pellet. The measured lattice parameters help clarify conflicting reports in the literaturemore » as these new results are more consistent with one set of previous results than another. The lattice parameters of pressed TATB were also measured as a function of temperature, showing some differences from the powder. This data is used along with anisotropic single-crystal stiffness moduli reported in the literature to model the nominal stresses associated with intergranular constraints during thermal expansion. The texture of both specimens were characterized and the pressed pellet exhibits preferential orientation of (001) poles along the pressing direction, whereas no preferred orientation was found for the loose powder. Lastly, thermal strains for single-crystal TATB computed from lattice parameter data for the powder is input to a self-consistent micromechanical model, which predicts the lattice parameters of the constrained TATB crystals within the pellet. The agreement of these model results with the diffraction data obtained from the pellet is discussed along with future directions of research.« less

  18. Model of curing shrinkage and kinetic parameters of an acrylate-based ultraviolet-embossing resist based on free volume theory

    NASA Astrophysics Data System (ADS)

    Liu, Nan; Liu, Jingbei; Lin, Jie; Davies, Graham; Jin, Peng; Zhang, Dou

    2013-04-01

    Free volume theory and a model of polymerization kinetics are introduced to predict and analyze the curing shrinkage and kinetic parameters of an acrylate-based ultraviolet-embossing resist. Curing shrinkage tests have been designed and performed to verify the accuracy of the model. The experimental results are in good agreement with the simulated results of the conversion behavior. The reaction coefficients of polymerization predicted by this model are essentially correct when compared to the classical experimental values. Moreover, the dynamic shrinkage during polymerization determined experimentally matches the simulated result predicted by our model.

  19. Latitudinal variations of cloud base height and lightning parameters in the tropics

    NASA Astrophysics Data System (ADS)

    Mushtak, V. C.; Williams, E. R.; Boccippio, D. J.

    2005-07-01

    The observed reduction in cloud-to-ground lightning in the near-equatorial zone is examined from the perspective of the width of the main negative charge region. Thermodynamic observations of cloud base height also show a climatological minimum value in the near-equatorial region. The association of low cloud bases with both narrow updrafts and narrow charging zones may impede the bridging of the large air gap to ground, and thereby suppress cloud-to-ground lightning activity. This width dependence may be more important than the ˜ 10% variation in height of the freezing level in encouraging flashes to ground.

  20. Latitudinal variations of cloud base height and lightning parameters in the tropics

    NASA Technical Reports Server (NTRS)

    Mushtak, V. C.; Williams, E. R.; Boccippio, D. J.

    2006-01-01

    The observed reduction in cloud-to-ground lightning in the new-equational zone is examined from the perspective of the width of the main negative charge region. Thermodynamic observations of cloud base height also show a climatological minimum value in the near-equatorial region. The association of low cloud base with both narrow updrafts and narrow changing zones may impede the bridging of the large air gap to ground, and thereby suppress cloud-to-ground lightning activity. This width dependence may be more important than the approx. 10% variation in height of the freezing level in the encouraging flashes to ground.

  1. Effect of growth parameters on compositional variations in directionally solidified HgCdTe alloys

    NASA Technical Reports Server (NTRS)

    Szofran, F. R.; Chandra, D.; Wang, J.-C.; Cothran, E. K.; Lehoczky, S. L.

    1984-01-01

    A series of Hg(1-x)Cd(x)Te alloy crystals was grown by directional solidification with compositions ranging from x = 0.2 to x = 0.4. The measured axial compositional profiles were interpreted in terms of an exact numerical solution of the appropriate diffusion equation that takes into account both the variations of the segregation coefficient and solidification rate with composition. The solutions for all growth rates agree generally well with the experimental data, and confirm earlier observations that employed approximate analytical solutions. The effective mass diffusion coefficients showed no significant composition or melt temperature dependence. Slightly higher diffusion coefficients were obtained, however, for the highest growth rates.

  2. Variations of solar, interplanetary, and geomagnetic parameters with solar magnetic multipole fields during Solar Cycles 21-24

    NASA Astrophysics Data System (ADS)

    Kim, Bogyeong; Lee, Jeongwoo; Yi, Yu; Oh, Suyeon

    2015-01-01

    In this study we compare the temporal variations of the solar, interplanetary, and geomagnetic (SIG) parameters with that of open solar magnetic flux from 1976 to 2012 (from Solar Cycle 21 to the early phase of Cycle 24) for a purpose of identifying their possible relationships. By the open flux, we mean the average magnetic field over the source surface (2.5 solar radii) times the source area as defined by the potential field source surface (PFSS) model of the Wilcox Solar Observatory (WSO). In our result, most SIG parameters except the solar wind dynamic pressure show rather poor correlations with the open solar magnetic field. Good correlations are recovered when the contributions from individual multipole components are counted separately. As expected, solar activity indices such as sunspot number, total solar irradiance, 10.7 cm radio flux, and solar flare occurrence are highly correlated with the flux of magnetic quadrupole component. The dynamic pressure of solar wind is strongly correlated with the dipole flux, which is in anti-phase with Solar Cycle (SC). The geomagnetic activity represented by the Ap index is correlated with higher order multipole components, which show relatively a slow time variation with SC. We also found that the unusually low geomagnetic activity during SC 23 is accompanied by the weak open solar fields compared with those in other SCs. It is argued that such dependences of the SIG parameters on the individual multipole components of the open solar magnetic flux may clarify why some SIG parameters vary in phase with SC and others show seemingly delayed responses to SC variation.

  3. Effect of the adsorbate (Bromacil) equilibrium concentration in water on its adsorption on powdered activated carbon. Part 2: Kinetic parameters.

    PubMed

    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). PMID:19560269

  4. Influence of Different Parameters on a Dual-Fractal Analysis for Antigen-Antibody Binding Kinetics for Biosensor Applications

    PubMed

    Milum; Sadana

    1997-03-01

    The diffusion-limited binding kinetics of antigen (or antibody) in solution to antibody (or antigen) immobilized on a biosensor surface is analyzed within a fractal framework. The fit obtained by a dual-fractal analysis is compared with that obtained from a single-fractal analysis. In some cases, the dual-fractal analysis provides an improved fit when compared with a single-fractal analysis. This was indicated by the regression analysis provided by Sigmaplot (46). It is of interest to note that the state of disorder (or the fractal dimension) and the binding rate coefficient both increase as the reaction progresses on the biosensor surface. For example, for the binding of HIV-1 p24 in solution to monoclonal antibody (MAb) 18 covalently attached to a biosensor surface (49), an increase in the fractal dimension by 59% from a value of Df1 equal to 1.91 to Df2 equal to 2.95 leads to an increase in the binding rate coefficient by a factor of 15 from k1 equal to 21.1 to k2 equal to 339. Also, the binding of MAb 6301 and 6303 in solution to insulin growth factor binding protein-1 (IGFBP-1) covalently attached to the sensor surface is adequately described by a single-fractal analysis (48). The binding of MAb 6302 to IGFBP-1, however, requires dual fractals. This indicates a difference in the binding mechanisms of these MAbs. The different examples analyzed and presented together provide a means by which the antigen-antibody reactions may be better controlled by noting the magnitude of the changes in the fractal dimension and in the binding rate coefficient as the reaction progresses on the biosensor surface. Also, the magnitude of the changes in the binding rate coefficients (k1 and k2) and in the fractal dimensions (Df1 and Df2) as different parameters are changed for the different biosensor applications are of particular value. PMID:9245322

  5. Multivariate statistical analysis of diffusion imaging parameters using partial least squares: Application to white matter variations in Alzheimer's disease.

    PubMed

    Konukoglu, Ender; Coutu, Jean-Philippe; Salat, David H; Fischl, Bruce

    2016-07-01

    Diffusion magnetic resonance imaging (dMRI) is a unique technology that allows the noninvasive quantification of microstructural tissue properties of the human brain in healthy subjects as well as the probing of disease-induced variations. Population studies of dMRI data have been essential in identifying pathological structural changes in various conditions, such as Alzheimer's and Huntington's diseases (Salat et al., 2010; Rosas et al., 2006). The most common form of dMRI involves fitting a tensor to the underlying imaging data (known as diffusion tensor imaging, or DTI), then deriving parametric maps, each quantifying a different aspect of the underlying microstructure, e.g. fractional anisotropy and mean diffusivity. To date, the statistical methods utilized in most DTI population studies either analyzed only one such map or analyzed several of them, each in isolation. However, it is most likely that variations in the microstructure due to pathology or normal variability would affect several parameters simultaneously, with differing variations modulating the various parameters to differing degrees. Therefore, joint analysis of the available diffusion maps can be more powerful in characterizing histopathology and distinguishing between conditions than the widely used univariate analysis. In this article, we propose a multivariate approach for statistical analysis of diffusion parameters that uses partial least squares correlation (PLSC) analysis and permutation testing as building blocks in a voxel-wise fashion. Stemming from the common formulation, we present three different multivariate procedures for group analysis, regressing-out nuisance parameters and comparing effects of different conditions. We used the proposed procedures to study the effects of non-demented aging, Alzheimer's disease and mild cognitive impairment on the white matter. Here, we present results demonstrating that the proposed PLSC-based approach can differentiate between effects of

  6. Tumor response parameters for head and neck cancer derived from tumor-volume variation during radiation therapy

    SciTech Connect

    Chvetsov, Alexei V.

    2013-03-15

    -and-neck squamous cell carcinoma (SCC) is equal to 3.8 mean potential doubling times, which agrees with 4.0 mean potential doubling times obtained previously for lung SCC. Conclusions: The distribution of cell survival fractions obtained in this study support the hypothesis that the tumor-volume variation during radiotherapy treatment for head and neck cancer can be described by the two-level cell population tumor-volume model. This model can be used for in vivo evaluation of patient-specific radiobiological parameters that are needed for tumor-control probability evaluation.

  7. An optimal output feedback gain variation scheme for the control of plants exhibiting gross parameter changes

    NASA Technical Reports Server (NTRS)

    Moerder, Daniel D.

    1987-01-01

    A concept for optimally designing output feedback controllers for plants whose dynamics exhibit gross changes over their operating regimes was developed. This was to formulate the design problem in such a way that the implemented feedback gains vary as the output of a dynamical system whose independent variable is a scalar parameterization of the plant operating point. The results of this effort include derivation of necessary conditions for optimality for the general problem formulation, and for several simplified cases. The question of existence of a solution to the design problem was also examined, and it was shown that the class of gain variation schemes developed are capable of achieving gain variation histories which are arbitrarily close to the unconstrained gain solution for each point in the plant operating range. The theory was implemented in a feedback design algorithm, which was exercised in a numerical example. The results are applicable to the design of practical high-performance feedback controllers for plants whose dynamics vary significanly during operation. Many aerospace systems fall into this category.

  8. A size-based emphysema severity index: robust to the breath-hold-level variations and correlated with clinical parameters

    PubMed Central

    Hwang, Jeongeun; Lee, Minho; Lee, Sang Min; Oh, Sang Young; Oh, Yeon-Mok; Kim, Namkug; Seo, Joon Beom

    2016-01-01

    Objective To determine the power-law exponents (D) of emphysema hole-size distributions as a competent emphysema index. Robustness to extreme breath-hold-level variations and correlations with clinical parameters for chronic obstructive pulmonary disease (COPD) were investigated and compared to a conventional emphysema index (EI%). Patients and methods A total of 100 patients with COPD (97 males and three females of mean age 67±7.9 years) underwent multidetector row computed tomography scanning at full inspiration and full expiration. The diameters of the emphysematous holes were estimated and quantified with a fully automated algorithm. Power-law exponents (D) of emphysematous hole-size distribution were evaluated. Results The diameters followed a power-law distribution in all cases, suggesting the scale-free nature of emphysema. D of inspiratory and expiratory computed tomography of patients showed intraclass correlation coefficients >0.8, indicating statistically absolute agreement of different breath-hold levels. By contrast, the EI% failed to agree. Bland–Altman analysis also revealed the superior robustness of D to EI%. D also significantly correlated with clinical parameters such as airflow limitation, diffusion capacity, exercise capacity, and quality of life. Conclusion The D of emphysematous hole-size distribution is robust to breath-hold-level variations and sensitive to the severity of emphysema. This measurement may help rule out the confounding effects of variations in breath-hold levels. PMID:27536095

  9. Uniform Invariance Principle and Synchronization. Robustness with Respect to Parameter Variation

    NASA Astrophysics Data System (ADS)

    Rodrigues, H. M.; Alberto, L. F. C.; Bretas, N. G.

    2001-01-01

    The objective of this work is to obtain uniform estimates, with respect to parameters, of the attractor and of the basin of attraction of a dynamical system and to apply these results to analyze the roughness of the synchronization of two subsystems. These estimates are obtained through a uniform version of the invariance principle of La Salle which is stated and proved in this work.

  10. The variation in molecular gas depletion time among nearby galaxies: what are the main parameter dependences?

    NASA Astrophysics Data System (ADS)

    Huang, Mei-Ling; Kauffmann, Guinevere

    2014-09-01

    We re-analyse correlations between global molecular gas depletion time (tdep) and galaxy parameters for nearby galaxies from the COLD GASS survey. We improve on previous work of Saintonge et al. by estimating star formation rates using the combination of Galaxy Evolution Explorer far-ultraviolet and Wide-field Infrared Survey Explorer 22 μm data and by deriving tdep within a fixed aperture set by the beam size of gas observation. In our new study, we find correlations with much smaller scatter. Dependences of the depletion time on galaxy structural parameters such as stellar surface density and concentration index are now weak or absent. We demonstrate that the primary global parameter correlation is between tdep and specific star formation rate (sSFR); all other remaining correlations can be shown to be induced by this primary dependence. This implies that galaxies with high current-to-past-averaged star formation activity, will drain their molecular gas reservoir sooner. We then analyse tdep on 1 kpc scales in galactic discs using data from the HERA CO-Line Extragalactic Survey survey. There is remarkably good agreement between the global tdep-sSFR relation for the COLD GASS galaxies and that derived for 1 kpc scale grids in discs. This leads to the conclusion that the local molecular gas depletion time in galactic discs is dependent on the local fraction of young-to-old stars.

  11. Variational optimization of sub-grid scale convection parameters. Final report

    SciTech Connect

    Zivkovic-Rothman, M.

    1997-11-25

    Under the DOE CHAMMP/CLIMATE Program, a convective scheme was developed for use in climate models. The purpose of the present study was to develop an adjoint model of its tangent-linear model. the convective scheme was integrated within a single column model which provides radiative-convective equilibrium solutions applicable to climate models. The main goal of this part of the project was to develop an adjoint of the scheme to facilitate the optimization of its convective parameters. For that purpose, adjoint sensitivities were calculated with the adjoint code. Parameter optimization was based on TOGA COARE data which were also used in this study to obtain integrations of the nonlinear and tangent-linear models as well as the integrations of the adjoint model. Some inadequacies of the inner IFA data array were found, and did not permit a single numerical integration during the entire 4 months of data. However, reliable monthly radiative-convective equilibrium solutions and associated adjoint sensitivities were obtained and used to bring about the parameter optimization.

  12. Variation in Immune Parameters and Disease Prevalence among Lesser Black-Backed Gulls (Larus fuscus sp.) with Different Migratory Strategies

    PubMed Central

    Arriero, Elena; Müller, Inge; Juvaste, Risto; Martínez, Francisco Javier; Bertolero, Albert

    2015-01-01

    The ability to control infections is a key trait for migrants that must be balanced against other costly features of the migratory life. In this study we explored the links between migration and disease ecology by examining natural variation in parasite exposure and immunity in several populations of Lesser Black-backed Gulls (Larus fuscus) with different migratory strategies. We found higher activity of natural antibodies in long distance migrants from the nominate subspecies L.f.fuscus. Circulating levels of IgY showed large variation at the population level, while immune parameters associated with antimicrobial activity showed extensive variation at the individual level irrespective of population or migratory strategy. Pathogen prevalence showed large geographical variation. However, the seroprevalence of one of the gull-specific subtypes of avian influenza (H16) was associated to the migratory strategy, with lower prevalence among the long-distance migrants, suggesting that migration may play a role in disease dynamics of certain pathogens at the population level. PMID:25679797

  13. Regional variations and correlations of Gutenberg-Richter parameters and fractal dimension for the different seismogenic zones in Western Anatolia

    NASA Astrophysics Data System (ADS)

    Bayrak, Yusuf; Bayrak, Erdem

    2012-09-01

    We investigated the regional variations of Gutenberg-Richter (G-R) parameters (a and b) and fractal (correlation) dimension (DC) and relations among these parameters for the different regions in Western Anatolia (WA). The whole examined area (26-33°E, 33-40.5°N) is divided into 15 different seismogenic regions based on their tectonic and seismotectonic regimes. We used database including 69,182 earthquakes for the instrumental period from 1900 to 2011. We calculated b value, which is the slope of the frequency-magnitude Gutenberg-Richter relationship, from maximum likelihood method (ML) and DC value, which is the slope of log10C(r) versus log10r, from correlation integral using the least-squares (LS) method. Computed values for 15 different seismogenic regions are mapped using different color scale for different range of values of b and DC. Regional distributions of these parameters reveal information about regional variation of stress level and geological complexity. We concluded Aegean arc and Aegean islands, Aliağa fault and Büyük Menderes Graben the most vulnerable regions for occurrence of the large earthquakes in WA considering the computed lowest b-values and the highest DC-values in these regions. Since DC/b values are the highest in these regions, this ratio may be used as an indicator of earthquake hazard levels of different seismogenic zones in a studied region. An effort is made to find relationships between the G-R parameters and fractal dimension. We observed negative correlation between DC and b values and positive correlation between DC and a/b values for different regions of WA. We observed that the relationship between a/b and DC can be used for seismicity, earthquake risk and hazard studies because of the computed high correlation coefficient and fewer scattering of these parameters.

  14. Breed variation and genetic parameters for growth and body development in diverse beef cattle genotypes.

    PubMed

    Afolayan, R A; Pitchford, W S; Deland, M P B; McKiernan, W A

    2007-02-01

    Conformation scores can account for more than 20% of cattle price variation at Australian livestock sales. However, there are limited available references which define genetic factors relating objective live developmental traits to carcass composition. Weaning and post-weaning weight, height, length, girth, muscle (ratio of stifle to hip width) and fat depth of 1202 progeny from mature Hereford cows (637) mated to seven sire breeds (Jersey, Wagyu, Angus, Hereford, South Devon, Limousin and Belgian Blue) were examined for growth and development across ages. Crossbred Wagyu and Jersey were both lighter in weight and smaller in size (height, length and girth) than purebred Hereford and crossbred Angus, South Devon, Limousin and Belgian Blue. Within the five larger crossbreds, there were significant changes in relative weight from weaning to 600 days. Sire breeds differed in fat depth, with Angus being the fattest (9% on average fatter than Hereford and Wagyu), and Jersey 5% less fat than Hereford, followed by South Devon and Limousin (19% lower than Hereford) and Belgian Blue (39% lower than Hereford). Direct heritability ranged from 19 to 42% and was higher than the proportion of total phenotypic variance accounted for by maternal effects (which ranged from 0 to 17%) for most body measurement traits except for weight (38 v. 18%) and girth (36 v. 9%) traits at weaning, an indication of maternal effect on some body conformation traits at early ages. Muscularity (19 to 44%) and fat depth (26 to 43%) were moderately to highly heritable across ages. There were large differences for growth and the objective measures of body development between crossbreds with a degree of overlap among the progeny of the seven sire breeds. The variation between genetic (positive) and environmental (negative) correlations for dry versus wet season average daily gains in weight and fat, suggested the potential use of live-animal conformation traits for within breed selection of genetically

  15. Towards noninvasive method for the detection of pathological tissue variations by mapping different blood parameters

    NASA Astrophysics Data System (ADS)

    Abdallah, Omar; Qananwah, Qasem; Abo Alam, Kawther; Bolz, Armin

    2010-04-01

    This paper describes the development of an early detection method for probing pathological tissue variations. The method could be used for classifying various tissue alteration namely tumors tissue or skin disorders. The used approach is based on light scattering and absorption spectroscopy. Spectral content of the scattered light provides diagnostic information about the tissue contents. The importance of this method is using a safe light that has less power than the used in the imaging methods that will enable the frequent examination of tissue, while the exiting modalities have drawbacks like ionization, high cost, time-consuming, and agents' usage. A modality for mapping the oxygen saturation distribution in tissues noninvasively is new in this area of research, since this study focuses on the oxygen molecule in the tissue which supposed to be homogenously distributed through the tissues. Cancers may cause greater vascularization and greater oxygen consumption than in normal tissue. Therefore, oxygen existence and homogeneity will be alternated depending on the tissue state. In the proposed system, the signal was extracted after illuminating the tissue by light emitting diodes (LED's) that emits light in two wavelengths, red (660 nm) and infrared (880 nm). The absorption in these wavelengths is mainly due to oxyhemoglobin (HbO2) and deoxyhemoglobin (Hb) while other blood and tissue contents nearly have low effect on the signal. The backscattered signal which is received by a photodiodes array (128 PDs) was measured and processed using LabVIEW. Photoplethysmogram (PPG) signals have been measured at different locations. These signals will be used to differentiate between the normal and the pathological tissues. Variations in hemoglobin concentration and blood perfusion will also be used as an important indication feature for this purpose.

  16. FAST TRACK COMMUNICATION: Variation of equation of state parameters in the Mg2(Si1 - xSnx) alloys

    NASA Astrophysics Data System (ADS)

    Pulikkotil, J. J.; Alshareef, H. N.; Schwingenschlögl, U.

    2010-09-01

    Thermoelectric performance peaks up for intermediate Mg2(Si1 - xSnx) alloys, but not for isomorphic and isoelectronic Mg2(Si1 - xGex) alloys. A comparative study of the equation of state parameters is performed using density functional theory, Green's function technique, and the coherent potential approximation. Anomalous variation of the bulk modulus is found in Mg2(Si1 - xSnx) but not in the Mg2(Si1 - xGex) analogs. Assuming a Debye model, linear variations of the unit cell volume and pressure derivative of the bulk modulus suggest that lattice effects are important for the thermoelectric response. From the electronic structure perspective, Mg2(Si1 - xSnx) is distinguished by a strong renormalization of the anion-anion hybridization.

  17. Variation of equation of state parameters in the Mg2(Si(1-x)Sn(x)) alloys.

    PubMed

    Pulikkotil, J J; Alshareef, H N; Schwingenschlögl, U

    2010-09-01

    Thermoelectric performance peaks up for intermediate Mg(2)(Si(1-x)Sn(x)) alloys, but not for isomorphic and isoelectronic Mg(2)(Si(1-x)Ge(x)) alloys. A comparative study of the equation of state parameters is performed using density functional theory, Green's function technique, and the coherent potential approximation. Anomalous variation of the bulk modulus is found in Mg(2)(Si(1-x)Sn(x)) but not in the Mg(2)(Si(1-x)Ge(x)) analogs. Assuming a Debye model, linear variations of the unit cell volume and pressure derivative of the bulk modulus suggest that lattice effects are important for the thermoelectric response. From the electronic structure perspective, Mg(2)(Si(1-x)Sn(x)) is distinguished by a strong renormalization of the anion-anion hybridization. PMID:21403277

  18. Variation in plasmonic (electronic) spectral parameters of Pr (III) and Nd (III) with varied concentration of moderators

    SciTech Connect

    Mishra, Shubha; Limaye, S. N.

    2015-07-31

    It is said that the -4f shells behave as core and are least perturbed by changes around metal ion surrounding. However, there are evidences that-4f shells partially involved in direct moderator interaction. A systematic investigation on the plasmonic (electronic) spectral studies of some Rare Earths[RE(III).Mod] where, RE(III) = Pr(III),Nd(III) and Mod(moderator) = Y(III),La(III),Gd(III) and Lu(III), increased moderator concentration from 0.01 mol dm{sup −3} to 0.025 mol dm{sup −3} keeping the metal ion concentration at 0.01mol dm{sup −3} have been carried out. Variations in oscillator strengths (f), Judd-Ofelt parameters (T{sub λ}),inter-electronic repulsion Racah parameters (δE{sup k}),nephelauxetic ratio (β), radiative parameters (S{sub ED},A{sub T},β{sub R},T{sub R}). The values of oscillator strengths and Judd-Ofelt parameters have been discussed in the light of coordination number of RE(III) metal ions, denticity and basicity of the moderators. The [RE(III).Mod] bonding pattern has been studies in the light of the change in Racah parameters and nephelauxetic ratio.

  19. Effects of stream-associated fluctuations upon the radial variation of average solar wind parameters

    NASA Technical Reports Server (NTRS)

    Goldstein, B. E.; Jokipii, J. R.

    1977-01-01

    A numerical MHD model in both spherically symmetric time-dependent and corotating equatorial flow approximations is used to compute the effects of nonlinear fluctuations due to solar wind streams upon radial gradients of average solar wind parameters. Significant effects of correlations between fluctuations on the gradients of azimuthal magnetic field, radial velocity, density, and azimuthal velocity are found. It is found that nonlinear fluctuations are a significant effect in determining the radial gradients of the solar wind at distances as small as 0.2 AU; at distances greater than 1 AU, nonlinear fluctuations dominate the behavior of the radial gradients.

  20. Reproductive parameters of tropical lesser noddies respond to local variations in oceanographic conditions and weather

    NASA Astrophysics Data System (ADS)

    Monticelli, David; Ramos, Jaime A.; Catry, Teresa; Pedro, Patricia; Paiva, Vitor H.

    2014-02-01

    Most attempts to link seabirds and climate/oceanographic effects have concerned the Atlantic and Pacific Oceans with comparatively few studies in the tropical Indian Ocean. This paper examines the reproductive response of the lesser noddy Anous tenuirostris to temporal fluctuations in oceanographic and climatic conditions using 8 years of monitoring data from Aride Island (Seychelles), tropical Western Indian Ocean. We tested the hypothesis that breeding parameters (mean hatching date, mean egg size, hatching and fledging successes) and chick growth are influenced by local, seasonal oceanographic conditions as expressed by ocean primary productivity (surface chlorophyll-a concentrations; CC), sea surface temperature (SST) and wind speed. We also examined the relationship between lesser noddy breeding parameters and climate conditions recorded at the basin-wide scale of the Indian Ocean (Indian Ocean Dipole Mode Index, DMI). Our findings suggest that birds had a tendency to lay slightly larger eggs during breeding seasons (years) with higher CC during April-June (pre-laying, laying and incubation periods). Hatching date was positively related to SST in April-June, with the regression parameters suggesting that each 0.5 °C increase in SST meant a delay of approx.10 days in hatching date. A negative linear relationship was also apparent between hatching success and SST in June-August (hatching and chick-rearing periods), while the quadratic regression models detected a significant effect of wind speed in June-August on fledging success. Body mass increments of growing chicks averaged over 7-day periods were positively related with (2-week) lagged CC values and negatively related with (2-week) lagged SST values. No significant relationship between DMI and lesser noddy breeding parameters was found, but DMI indices were strongly correlated with local SST. Altogether, our results indicate that the reproduction of this top marine predator is dictated by fluctuations in

  1. Analysis of the Intra-City Variation of Urban Heat Island and its Relation to Land Surface/cover Parameters

    NASA Astrophysics Data System (ADS)

    Gerçek, D.; Güven, İ. T.; Oktay, İ. Ç.

    2016-06-01

    Along with urbanization, sealing of vegetated land and evaporation surfaces by impermeable materials, lead to changes in urban climate. This phenomenon is observed as temperatures several degrees higher in densely urbanized areas compared to the rural land at the urban fringe particularly at nights, so-called Urban Heat Island. Urban Heat Island (UHI) effect is related with urban form, pattern and building materials so far as it is associated with meteorological conditions, air pollution, excess heat from cooling. UHI effect has negative influences on human health, as well as other environmental problems such as higher energy demand, air pollution, and water shortage. Urban Heat Island (UHI) effect has long been studied by observations of air temperature from thermometers. However, with the advent and proliferation of remote sensing technology, synoptic coverage and better representations of spatial variation of surface temperature became possible. This has opened new avenues for the observation capabilities and research of UHIs. In this study, "UHI effect and its relation to factors that cause it" is explored for İzmit city which has been subject to excess urbanization and industrialization during the past decades. Spatial distribution and variation of UHI effect in İzmit is analysed using Landsat 8 and ASTER day & night images of 2015 summer. Surface temperature data derived from thermal bands of the images were analysed for UHI effect. Higher temperatures were classified into 4 grades of UHIs and mapped both for day and night. Inadequate urban form, pattern, density, high buildings and paved surfaces at the expanse of soil ground and vegetation cover are the main factors that cause microclimates giving rise to spatial variations in temperatures across cities. These factors quantified as land surface/cover parameters for the study include vegetation index (NDVI), imperviousness (NDISI), albedo, solar insolation, Sky View Factor (SVF), building envelope

  2. Current Sensor Offset and Motor Parameter Variations Estimation Method for PM Motor by Using Current Simulator

    NASA Astrophysics Data System (ADS)

    Sazawa, Masaki; Senko, Tomohiro; Uenaka, Yutaro; Ohishi, Kiyoshi

    The servo system of a PM motor is required to have a fine torque response and fine speed response. The current controller of the PM motor should have a fine current response. However, when the current sensors of the U phase and V phase have offset values, the servo system of the PM motor shows a torque ripple and cannot accurately identify motor parameters such as the motor resistance Ra and motor inductance La. In order to overcome these problems, this paper proposes a new method for the fine estimation and automatic adjustment of current sensor offsets and the electrical parameters of the PM motor. The proposed method involves the use of a real-time algorithm and a current simulator, which is operated using a DSP software system. The experimental results of this study confirm that the proposed method satisfactorily estimates the offsets of the current of sensors of theU phase and V phase, Ra, and La accurately; the method also helps in the fine self-tuning of the current controller of the servo system.

  3. Effect of parameter variations on the hemodynamic response under rotary blood pump assistance.

    PubMed

    Lim, Einly; Dokos, Socrates; Salamonsen, Robert F; Rosenfeldt, Franklin L; Ayre, Peter J; Lovell, Nigel H

    2012-05-01

    Numerical models, able to simulate the response of the human cardiovascular system (CVS) in the presence of an implantable rotary blood pump (IRBP), have been widely used as a predictive tool to investigate the interaction between the CVS and the IRBP under various operating conditions. The present study investigates the effect of alterations in the model parameter values, that is, cardiac contractility, systemic vascular resistance, and total blood volume on the efficiency of rotary pump assistance, using an optimized dynamic heart-pump interaction model previously developed in our laboratory based on animal experimental measurements obtained from five canines. The effect of mean pump speed and the circulatory perturbations on left and right ventricular pressure volume loops, mean aortic pressure, mean cardiac output, pump assistance ratio, and pump flow pulsatility from both the greyhound experiments and model simulations are demonstrated. Furthermore, the applicability of some of the previously proposed control parameters, that is, pulsatility index (PI), gradient of PI with respect to pump speed, pump differential pressure, and aortic pressure are discussed based on our observations from experimental and simulation results. It was found that previously proposed control strategies were not able to perform well under highly varying circulatory conditions. Among these, control algorithms which rely on the left ventricular filling pressure appear to be the most robust as they emulate the Frank-Starling mechanism of the heart. PMID:22489771

  4. Anomalous Variation in GPS TEC, Land and Ocean Parameters Prior to 3 Earthquakes

    NASA Astrophysics Data System (ADS)

    Yadav, Kunvar; Karia, Sheetal P.; Pathak, Kamlesh N.

    2016-02-01

    The present study reports the analysis of GPS TEC prior to 3 earthquakes (M > 6.0). The earthquakes are: (1) Loyalty Island (22°36'S, 170°54'E) on 19 January 2009 (M = 6.6), (2) Samoa Island (15°29'S, 172°5'W) on 30 August 2009 (M = 6.6), and (3) Tohoku (38°19'N, 142°22'E) on 11 March 2011 (M = 9.0). In an effort to search for a precursory signature we analysed the land and ocean parameters prior to the earthquakes, namely SLHF (Land) and SST (Ocean). The GPS TEC data indicate an anomalous behaviour from 1-13 days prior to earthquakes. The main purpose of this study was to explore and demonstrate the possibility of any changes in TEC, SST, and SLHF before, during and after the earthquakes which occurred near or beneath an ocean. This study may lead to better understanding of response of land, ocean, and ionosphere parameters prior to seismic activities.

  5. Monthly variation of some parameters about internal solitary waves in the South China sea

    NASA Astrophysics Data System (ADS)

    Cai, Shuqun; Xie, Jieshuo; Xu, Jiexin; Wang, Dongxiao; Chen, Zhiwu; Deng, Xiaodong; Long, Xiaomin

    2014-02-01

    In this paper, by non-dimensional analysis, it is found that finite-depth theory is more appropriate to the study of internal solitary waves (ISWs) in the South China Sea (SCS) than shallow-water theory. The 1-degree grid data of monthly mean temperature and salinity data at standard levels in the SCS are used to solve the linearized vertical eigenvalue problem. The nonlinear parameter and the wave phase speed are computed, then the nonlinear phase speed and the characteristic half-width of ISWs are calculated respectively by two different theories to investigate the difference between these two parameters in the SCS. The nonlinearity is the strongest near the continental slope of the SCS or islands where the bottom topography changes sharply, it is stronger in summer than that in winter; it increases (decreases) as pycnocline depth deepens (shallows), stratification strengthens (weakens) and pycnocline thickness thins (thickens). The nonlinear wave phase speed and the characteristic half-width are the largest in deep sea area, they then reduce peripherally in shallower water. The nonlinear wave phase speed in the SCS changes slightly with time, but the characteristic half-width changes somewhat larger with time. In most of the SCS basin, the nonlinear wave phase speed derived from shallow-water theory is very close to that derived from finite-depth theory, but the characteristic half-width derived from shallow-water theory is about 0.2-0.6 times larger than that derived from finite-depth theory. The ISW induced horizontal current velocity derived from shallow-water theory is larger than that derived from finite-depth theory. Some observed and numerical modeled ISW characteristic half-widths are compared with those derived from shallow-water and finite-depth theories, respectively. It is shown that, the characteristic half-widths derived from finite-depth theory agree better with observational and numerical modeled results than those derived from shallow

  6. Active experiments in the ionosphere and variations of geophysical and meteorological parameters

    NASA Astrophysics Data System (ADS)

    Sivokon, Vladimir; Cherneva, Nina; Shevtsov, Boris

    Energy distribution in ionospheric-magnetospheric relations, as one of the possible external climatological factors, may be traced on the basis of the analysis of natural geophysical phenomena such as ionosphere artificial radio radiation and magnetic storms. Development of magnetic disturbances is, to some extent, associated with current variations in electrojet. In its turn, some technologies are known which may affect electrojet and its characteristics. The method, developed by the authors, is based on a complex comparison of different geophysical fields and allows us to determine the degree of active experiment effect on energy change in ionospheric-magnetospheric relations and to evaluate on this basis the degree of active experiment effect on climate in the ionosphere. Within the framework of RAS Presidium Program Project “Determination of climate-forming characteristic changes on the basis of monitoring of geophysical field variations”, investigations have been carried out, which showed the possibility of ionosphere modification effect on the energy of magnetospheric-ionospheric relations. Evaluation of possible climate changes considering ionospheric-magnetospheric relations has not been previously discussed.

  7. Parameter variation and scenario analysis in impact assessments of emerging energy technologies

    NASA Astrophysics Data System (ADS)

    Breunig, Hanna Marie

    There is a global need for energy technologies that reduce the adverse impacts of societal progress and that address today's challenges without creating tomorrow's problems. Life cycle impact assessment (LCIA) can support technology developers in achieving these prerequisites of sustainability by providing a systems perspective. However, modeling the early-stage scale up and impacts of technology systems may lead to unreliable or incomplete results due to a lack of representative technical, spatial, and temporal data. The goal of this dissertation is to support the acceleration of clean energy technology development by providing information about the regional variation of impacts and benefits resulting from plausible deployment scenarios. Three emerging energy technologies are selected as case studies: (1) brine management for carbon dioxide sequestration; (2) carbon dioxide capture, utilization, and sequestration; (3) stationary fuel cells for combined heat and power in commercial buildings. In all three case studies, priority areas are identified where more reliable data and models are necessary for reducing uncertainty, and vital information is revealed on how impacts vary spatially and temporally. Importantly, moving away from default technology and waste management hierarchies as a source of data fosters goal-driven systems thinking which in turn leads to the discovery of technology improvement potentials.

  8. Two-parameter model of total solar irradiance variation over the solar cycle

    NASA Technical Reports Server (NTRS)

    Pap, Judit M.; Willson, Richard C.; Donnelly, Richard F.

    1991-01-01

    Total solar irradiance measured by the SMM/ACRIM radiometer is modelled from the Photometric Sunspot Index and the Mg II core-to-wing ratio with multiple regression analysis. Considering that the formation of the Mg II line is very similar to that of the Ca II K line, the Mg II core-to-wing ratio, measured by the Nimbus-7 and NOAA9 satellites, is used as a proxy for the bright magnetic elements, including faculae and the magnetic network. It is shown that the relationship between the variations in total solar irradiance and the above solar activity indices depends upon the phase of the solar cycle. Thus, a better fit between total irradiance and its model estimates can be achieved if the irradiance models are calculated for the declining portion and minimum of solar cycle 21, and the rising portion of solar cycle 22, respectively. There is an indication that during the rising portion of solar cycle 22, similar to the maximum time of solar cycle 21, the modelled total irradiance values underestimate the measured values. This suggests that there is an asymmetry in the long-term total irradiance variability.

  9. Spatial variation of physicochemical and bacteriological parameters elucidation with GIS in Rangat Bay, Middle Andaman, India

    NASA Astrophysics Data System (ADS)

    Dheenan, P. S.; Jha, Dilip Kumar; Vinithkumar, N. V.; Ponmalar, A. Angelin; Venkateshwaran, P.; Kirubagaran, R.

    2014-01-01

    The purpose of this study was to determine the concentration, distribution of bacteria and physicochemical property of surface seawater in Rangat Bay, Middle Andaman, Andaman Islands (India). The bay experiences tidal variations. Perhaps physicochemical properties of seawater in Rangat Bay were found not to vary significantly. The concentration of faecal streptococci was high (2.2 × 103 CFU/100 mL) at creek and harbour area, whereas total coliforms were high (7.0 × 102 CFU/100 mL) at mangrove area. Similarly, total heterotrophic bacterial concentration was high (5.92 × 104 CFU/100 mL) in mangrove and harbour area. The Vibrio cholerae and Vibrio parahaemolyticus concentration was high (4.2 × 104 CFU/100 mL and 9 × 103 CFU/100 mL) at open sea. Cluster analysis showed grouping of stations in different tidal periods. The spatial maps clearly depicted the bacterial concentration pattern in the bay. The combined approach of multivariate analysis and spatial mapping techniques was proved to be useful in the current study.

  10. Variation in water chemistry parameters in the Clayburn Creek watershed, British Columbia during fall 2015.

    NASA Astrophysics Data System (ADS)

    Marsh, S. J.; Gillies, S. L.; Peucker-Ehrenbrink, B.; Janmaat, A.; Clemence, E.; Faber, A.; Yakemchuk, A.; McCabe, M.; Toner, A.; Strangway, A.; Turner, S.; Sidhu, D.; Sidhu, B.; Sekhton, J.; Puri, K.; Paulson, D.; Mahil, G.; Leffers, R.; Kanda, S.; Gaultier, M.; Dhaliwal, H.

    2015-12-01

    faculty and students from the University of the Fraser Valley have conducted the time series sampling of water chemistry of the Fraser River at Fort Langley and five Fraser Valley tributaries as a member of the Global Rivers Observatory (GRO, www.globalrivers.org) organized by Woods Hole Oceanographic Institution and Woods Hole Research Center. Clayburn Creek and Willband Creek in Abbotsford, British Columbiahave been part of this project and have been sampled for nutrient and major ion concentrations and parameters such as water temperature, dissolved oxygen, conductivity, pH and turbidity. This watershed is being threatened by increasing anthropogenic activity (agricultural, industrial and residential development) that may threaten the salmon that spawn in this watershed. Documenting the change in the water chemistry in this watershed as the seasons progress from a dry summer to a wet fall will yield a greater understanding of our impact on this watershed and may assist our attempts to protect this watershed.

  11. Effects of stream-associated fluctuations upon the radial variation of average solar-wind parameters

    NASA Technical Reports Server (NTRS)

    Goldstein, B. E.; Jokipii, J. R.

    1976-01-01

    The effects of nonlinear fluctuations due to solar wind streams upon radial gradients of average solar wind parameters are computed, using a numerical MHD model for both spherically symmetric time dependent and corotating equatorial flow approximations. Significant effects of correlations are found between fluctuations upon the gradients of azimuthal magnetic fields, radial velocity, density and azimuthal velocity. Between 400 to 900 solar radii stream interactions have transferred the major portion of the angular momentum flux to the magnetic field; at even greater distances the plasma again carries the bulk of the angular momentum flux. The average azimuthal component of the magnetic field may decrease as much as 10% faster than the Archimedean spiral out to 6 AU due to stream interactions, but this result is dependent upon inner boundary conditions.

  12. Impact of parameter variation in fabrication of nanostructure by atomic force microscopy nanolithography.

    PubMed

    Dehzangi, Arash; Larki, Farhad; Hutagalung, Sabar D; Goodarz Naseri, Mahmood; Majlis, Burhanuddin Y; Navasery, Manizheh; Hamid, Norihan Abdul; Noor, Mimiwaty Mohd

    2013-01-01

    In this letter, we investigate the fabrication of Silicon nanostructure patterned on lightly doped (10(15) cm(-3)) p-type silicon-on-insulator by atomic force microscope nanolithography technique. The local anodic oxidation followed by two wet etching steps, potassium hydroxide etching for silicon removal and hydrofluoric etching for oxide removal, are implemented to reach the structures. The impact of contributing parameters in oxidation such as tip materials, applying voltage on the tip, relative humidity and exposure time are studied. The effect of the etchant concentration (10% to 30% wt) of potassium hydroxide and its mixture with isopropyl alcohol (10%vol. IPA ) at different temperatures on silicon surface are expressed. For different KOH concentrations, the effect of etching with the IPA admixture and the effect of the immersing time in the etching process on the structure are investigated. The etching processes are accurately optimized by 30%wt. KOH +10%vol. IPA in appropriate time, temperature, and humidity. PMID:23776479

  13. Relationship between human physiological parameters and geomagnetic variations of solar origin

    NASA Astrophysics Data System (ADS)

    Dimitrova, S.

    Results presented concern influence of increased geomagnetic activity on some human physiological parameters. The blood pressure and heart rate of 86 volunteers were measured on working days in autumn 2001 (01/10 09/11) and in spring 2002 (08/04 28/05). These periods were chosen because of maximal expected geomagnetic activity. Altogether 2799 recordings were obtained and analysed. Questionnaire information about subjective psycho-physiological complaints was also gathered. MANOVA was employed to check the significance of the influence of three factors on the physiological parameters under consideration. The factors were the following: (1) planetary geomagnetic activity level estimated by Ap-index and divided into five levels; (2) gender males and females; (3) blood pressure degree persons in the group examined were divided into hypotensive, normotensive and hypertensive. Post hoc analysis was performed to elicit the significance of differences in the factors’ levels. The average arterial blood pressure of the group was found to increase significantly with the increase of geomagnetic activity level. The average increment of systolic and diastolic blood pressure of the group examined reached 9%. This effect was present irrespectively of gender. Results obtained suppose that hypertensive persons have the highest sensitivity and the hypotensive persons have the lowest sensitivity of the arterial blood pressure to increase of geomagnetic activity. The results did not show significant changes in the heart rate. The percentage of the persons who reported subjective psycho-physiological complaints was also found to increase significantly with the geomagnetic activity increase and the highest sensitivity was revealed for the hypertensive females.

  14. Seasonal changes of buffalo colostrum: physicochemical parameters, fatty acids and cholesterol variation

    PubMed Central

    2013-01-01

    Background Colostrum has many beneficial effects on newborns due to its main compounds (proteins, fats, lactose, essential fatty acids, amino acids) as well as protective antibodies that confer to the body. The buffaloes are the second important species for milk production in the world after cows. The importance of the species is also conferred by a longer longevity, high dry content of milk and a strong organic resistance when compared with cows. The purpose of this study was to investigate the changes of buffalo colostrum compounds such as fatty acids, cholesterol and physicochemical parameters during the first seven days postpartum and under the impact of the season, summer on pasture and winter on dry diet (hay based). Results Fat from colostrum differs depending on the postpartum day showing mean values of 11.31-7.56% (summer season) and 11.22-7.51% (winter season). These values gradually decreased starting with first day postpartum until day seven. Dry substance and protein presented a similar evolution to fat reaching the lowest values at the end of the colostral period. Lactose, ash and pH showed a gradually increase reaching the maximum on day seven postpartum. The highest titres of fatty acids from colostrum are: butyric acid (C4:0), myristic acid (C14:0), palmitic acid (C16:0), oleic acid (C18:1) and the lowest values showed up in myristoleic acid (C14:1), cis-10-pentadecanoic acid (C15:1), pentadecylic acid (C15:0) and margaric acid (C17:0) for both seasons. Higher concentrations have been recorded for the summer season in general. Cholesterol concentration decreased from 12.93 and 12.68 mg/100 mL (summer and winter season) to 9.02 and 7.88 mg/100 mL in the end of the colostral period. Conclusions Physicochemical compounds of buffalo colostrum were influenced by season and postpartum day of milking. Excepting lactose all other parameters gradually decreased during colostral period. Fatty acids and cholesterol showed the same evolution, presenting higher

  15. Variation of patient imaging doses with scanning parameters for linac-integrated kilovoltage cone beam CT.

    PubMed

    Liao, Xiongfei; Wang, Yunlai; Lang, Jinyi; Wang, Pei; Li, Jie; Ge, Ruigang; Yang, Jack

    2015-01-01

    To evaluate the Elekta kilovoltage CBCT doses and the associated technical protocols with patient dosimetry estimation. Image guidance technique with cone-beam CT (CBCT) in radiation oncology on a daily basis can deliver a significant dose to the patient. To evaluate the patient dose from LINAC-integrated kV cone beam CT imaging in image-guided radiotherapy. CT dose index (CTDI) were measured with PTW TM30009 CT ion chamber in air, in head phantom and body phantom, respectively; with different combinations of tube voltage, current, exposure time per frame, collimator and gantry rotation range. Dose length products (DLP) were subsequently calculated to account for volume integration effects. The CTDI and DLP were also compared to AcQSim™ simulator CT for routine clinical protocols. Both CTDIair and CTDIw depended quadratically on the voltage, while linearly on milliampere x seconds (mAs) settings. It was shown that CTDIw and DLP had very close relationship with the collimator settings and the gantry rotation ranges. Normalized CTDIw for Elekta XVI™ CBCT was lower than that of ACQSim simulator CT owing to its pulsed radiation output characteristics. CTDIw can be used to assess the patient dose in CBCT due to its simplicity for measurement and reproducibility. Regular measurement should be performed in QA & QC program. Optimal image parameters should be chosen to reduce patient dose during CBCT. PMID:26405932

  16. Variation of Biophysical Parameters of the Skin with Age, Gender, and Body Region

    PubMed Central

    Firooz, Alireza; Sadr, Bardia; Babakoohi, Shahab; Sarraf-Yazdy, Maryam; Fanian, Ferial; Kazerouni-Timsar, Ali; Nassiri-Kashani, Mansour; Naghizadeh, Mohammad Mehdi; Dowlati, Yahya

    2012-01-01

    Background. Understanding the physiological, chemical, and biophysical characteristics of the skin helps us to arrange a proper approach to the management of skin diseases. Objective. The aim of this study was to measure 6 biophysical characteristics of normal skin (sebum content, hydration, transepidermal water loss (TEWL), erythema index, melanin index, and elasticity) in a normal population and assess the effect of sex, age, and body location on them. Methods. Fifty healthy volunteers in 5 age groups (5 males and females in each) were enrolled in this study. A multifunctional skin physiology monitor (Courage & Khazaka electronic GmbH, Germany) was used to measure skin sebum content, hydration, TEWL, erythema index, melanin index, and elasticity in 8 different locations of the body. Results. There were significant differences between the hydration, melanin index, and elasticity of different age groups. Regarding the locations, forehead had the highest melanin index, where as palm had the lowest value. The mean values of erythema index and melanin index and TEWL were significantly higher in males and anatomic location was a significant independent factor for all of 6 measured parameters. Conclusion. Several biophysical properties of the skin vary among different gender, age groups, and body locations. PMID:22536139

  17. The first orbital parameters and period variation of the short-period eclipsing binary AQ Boo

    NASA Astrophysics Data System (ADS)

    Wang, Shuai; Zhang, Liyun; Pi, Qingfeng; Han, Xianming L.; Zhang, Xiliang; Lu, Hongpeng; Wang, Daimei; Li, TongAn

    2016-10-01

    We obtained the first VRI CCD light curves of the short-period contact eclipsing binary AQ Boo, which was observed on March 22 and April 19 in 2014 at Xinglong station of National Astronomical Observatories, and on January 20, 21 and February 28 in 2015 at Kunming station of Yunnan Observatories of Chinese Academy of Sciences, China. Using our six newly obtained minima and the minima that other authors obtained previously, we revised the ephemeris of AQ Boo. By fitting the O-C (observed minus calculated) values of the minima, the orbital period of AQ Boo shows a decreasing tendency P˙ = - 1.47(0.17) ×10-7 days/year. We interpret the phenomenon by mass transfer from the secondary (more massive) component to the primary (less massive) one. By using the updated Wilson & Devinney program, we also derived the photometric orbital parameters of AQ Boo for the first time. We conclude that AQ Boo is a near contact binary with a low contact factor of 14.43%, and will become an over-contact system as the mass transfer continues.

  18. On the Solar Cycle Variations in the Heliospheric Parameters and Galactic Cosmic Ray Intensity

    NASA Astrophysics Data System (ADS)

    Krainev, M. B.; Webber, W. R.

    We briefly consider how the different branches of solar activity characterized by the toroidal (active regions) and poloidal solar magnetic fields are transformed in the course of the transition from the photosphere to the inner and then to the outer heliosphere and to the heliopause. In this process they are influencing each other and loose their identity, transforming in the region inside the termination shock into two groups of the heliospheric parameters changing with the 11- and 22-year periods. Beyond the termination shock in some layer adjacent to the heliopause the relation to the individual solar cycle is lost and the plasma and magnetic field characteristics there are governed by the combined influence of several previous solar cycles. We put forward and discuss an assumption that (1) the galactic cosmic ray (GCR) intensity inside the termination shock can be described as a function of two independent variables, representing the above (11- and 22-year) groups and (2) the GCR modulation in the mentioned (adjacent to the heliopause) layer contributes significantly to the residual GCR modulation in the heliosphere.

  19. The Social Network of Tracer Variations and O(100) Uncertain Photochemical Parameters in the Community Atmosphere Model

    NASA Astrophysics Data System (ADS)

    Lucas, D. D.; Labute, M.; Chowdhary, K.; Debusschere, B.; Cameron-Smith, P. J.

    2014-12-01

    Simulating the atmospheric cycles of ozone, methane, and other radiatively important trace gases in global climate models is computationally demanding and requires the use of 100's of photochemical parameters with uncertain values. Quantitative analysis of the effects of these uncertainties on tracer distributions, radiative forcing, and other model responses is hindered by the "curse of dimensionality." We describe efforts to overcome this curse using ensemble simulations and advanced statistical methods. Uncertainties from 95 photochemical parameters in the trop-MOZART scheme were sampled using a Monte Carlo method and propagated through 10,000 simulations of the single column version of the Community Atmosphere Model (CAM). The variance of the ensemble was represented as a network with nodes and edges, and the topology and connections in the network were analyzed using lasso regression, Bayesian compressive sensing, and centrality measures from the field of social network theory. Despite the limited sample size for this high dimensional problem, our methods determined the key sources of variation and co-variation in the ensemble and identified important clusters in the network topology. Our results can be used to better understand the flow of photochemical uncertainty in simulations using CAM and other climate models. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and supported by the DOE Office of Science through the Scientific Discovery Through Advanced Computing (SciDAC).

  20. Radiative heating and cooling in the middle and lower atmosphere of Venus and responses to atmospheric and spectroscopic parameter variations

    NASA Astrophysics Data System (ADS)

    Haus, R.; Kappel, D.; Arnold, G.

    2015-11-01

    A sophisticated radiative transfer model that considers absorption, emission, and multiple scattering by gaseous and particulate constituents over the broad spectral range 0.125-1000 μm is applied to calculate radiative fluxes and temperature change rates in the middle and lower atmosphere of Venus (0-100 km). Responses of these quantities to spectroscopic and atmospheric parameter variations are examined in great detail. Spectroscopic parameter studies include the definition of an optimum spectral grid for monochromatic calculations as well as comparisons for different input data with respect to spectral line databases, continuum absorption, line shape factors, and solar irradiance spectra. Atmospheric parameter studies are based on distinct variations of an initial model data set. Analyses of actual variations of the radiative energy budget using atmospheric features that have been recently retrieved from Venus Express data will be subject of a subsequent paper. The calculated cooling (heating) rates are very reliable at altitudes below 95 (85) km with maximum uncertainties of about 0.25 K/day. Heating uncertainties may reach 3-5 K/day at 100 km. Using equivalent Planck radiation as solar insolation source in place of measured spectra is not recommended. Cooling rates strongly respond to variations of atmospheric thermal structure, while heating rates are less sensitive. The influence of mesospheric minor gas variations is small, but may become more important near the cloud base and in case of episodic SO2 boosts. Responses to cloud mode 1 particle abundance changes are weak, but variations of other mode parameters (abundances, cloud top and base altitudes) may significantly alter radiative temperature change rates up to 50% in Venus' lower mesosphere and upper troposphere. A new model for the unknown UV absorber for two altitude domains is proposed. It is not directly linked to cloud particle modes and permits an investigation of radiative effects regardless of

  1. Variations of magnetic and electrostatic atmospheric parameters and dynamics of the heart rate in mHz range

    NASA Astrophysics Data System (ADS)

    Nagorskiy, Petr; Zenchenko, Tatiana; Breus, Tamara; Smirnov, Sergey

    The objective of this work was to study the degree of synchronization of heart rate (HR) of healthy volunteers with magnetic variations and various weather conditions in mHz - frequency range. Experimental results for synchronic registration of physiological variations, atmospheric electrical and meteorological parameters with a time resolution of 0.5-1 min are presented. The experiment was conducted in a building of IMCES SB RAS (Tomsk). 15 experiments of 60 minutes each were conducted, and four volunteers of all ages in a state of rest were examined. Meteorological parameters (atmospheric pressure, relative air humidity and temperatureas well as a wind speed) were measured using standard meteorological devices located on the roof of the same building and also on the open area. Data on geomagnetic activity on the nearest magnetic station Klyichi were obtained from the site http://ottawa.intermagnet.org/apps/download/index-eng.php # view. The electric field intensity was recorded the following way: in the room (5-storey panel ferroconcrete building) by the autonomous fluxmeter CS110 at a distance of 1.5 meters from the investigated volunteers, and on the open test - area by the stationary electric fluxmeter "Field 2". Data analysis techniques were: cross-correlation analysis, spectral analysis (Fourier transform and the calculation of the coherence function) and wavelet analysis. It was found that the dependence of the heart rate variation dynamics from the X-component of the Earth magnetic field magnitude was observed in 53% of cases, from the relative humidity - in 33%, from the atmospheric pressure, the wind speed and intensity of the electric field in an open area - in 20%, from the intensity the electric field in the room of the experiment - in 7% of cases. It was found not only coincidence of observed values of oscillation periods in physiological and geophysical series lasting 5-30 minutes, but also moments of approximate synchronicity in their appearance

  2. Application of the genetic algorithm to estimate the parameters related to the kinetics of the reduction of the iron ore, coal mixture

    SciTech Connect

    Kumar, A.; Roy, G.G.

    2005-12-01

    A novel methodology has been developed to calculate the kinetic parameters associated with reduction of ore-coal composite mixtures and to describe the time course of reduction of hematite to iron. The empirical parameters, namely, the three sets of activation energies and frequency factors, have been estimated by employing an evolutionary optimization tool, the genetic algorithm (GA). The model prediction matches well with the experimental literature data. The estimated activation energies are higher than the corresponding intrinsic values, indicating the role of heat transfer in the process.

  3. Displacement cascades and defect annealing in tungsten, Part III: The sensitivity of cascade annealing in tungsten to the values of kinetic parameters

    SciTech Connect

    Nandipati, Giridhar; Setyawan, Wahyu; Heinisch, Howard L.; Roche, Kenneth J.; Kurtz, Richard J.; Wirth, Brian D.

    2015-07-01

    Object kinetic Monte Carlo (OKMC) simulations have been performed to investigate various aspects of cascade aging in bulk tungsten and to determine the sensitivity of the results to the kinetic parameters. The primary focus is on how the kinetic parameters affect the initial recombination of defects in the first few ns of a simulation. The simulations were carried out using the object kinetic Monte Carlo (OKMC) code KSOME (kinetic simulations of microstructure evolution), using a database of cascades obtained from results of molecular dynamics (MD) simulations at various primary knock-on atom (PKA) energies and directions at temperatures of 300, 1025 and 2050 K. The OKMC model was parameterized using defect migration barriers and binding energies from ab initio calculations. Results indicate that, due to the disparate mobilities of SIA and vacancy clusters in tungsten, annealing is dominated by SIA migration even at temperatures as high as 2050 K. For 100 keV cascades initiated at 300 K recombination is dominated by annihilation of large defect clusters. But for all other PKA energies and temperatures most of the recombination is due to the migration and rotation of small SIA clusters, while all the large SIA clusters escape the cubic simulation cell. The inverse U-shape behavior exhibited by the annealing efficiency as a function of temperature curve, especially for cascades of large PKA energies, is due to asymmetry in SIA and vacancy clustering assisted by the large difference in mobilities of SIAs and vacancies. This annealing behavior is unaffected by the dimensionality of SIA migration persists over a broad range of relative mobilities of SIAs and vacancies.

  4. The solar cycle variations of plasma parameters and their correlations at topside ionosphere from DEMETER during 2005-2010

    NASA Astrophysics Data System (ADS)

    Zhang, Xuemin; Shen, Xuhui; Yuan, Guiping

    2015-10-01

    Based on the IAP (Instrument d'Analyse du Plasma) observing data onboard DEMETER satellite, the solar cycle variations in ion density (Ni), ion composition [O+, H+, He+] and ion temperature (Ti) were analyzed respectively in local daytime 10:30 and nighttime 22:30 during 2005-2010 during the 23rd/24th solar cycles, which would greatly contribute to the research of the topside ionospheric physics during this extremely low solar minimum. Based on analyzing the solar cycle variations of these plasma parameters, it was found that longitude-averaged Ni, [O+] and daytime Ti presented positive correlation with solar flux, while [H+], nighttime Ti and [He+] varied negatively to reach their maxima at the solar minimum. Furthermore, [O+], as the main composition at the altitude of DEMETER of 660 km, showed typical seasonal variation and close relationship with sub-solar dynamics. Daytime [He+] was the most complex component, showing negative variation with solar activity at low latitudes over Southern Hemisphere and positive correlation at middle latitudes over Northern Hemisphere. The correlation of Ni and Ti in local daytime was dependent on season over two hemispheres, and the results illustrated negative correlation at low latitudes, and positive correlation at middle latitudes especially over Southern Hemisphere in solstitial seasons. While [H+] presented anti-correlation, especially the peak values with Ti valleys at 0-20°N in each year, which all might be related to the thermal diffusion and relative drift among different ions. Furthermore, the asymmetrical features of Ni over two hemispheres in solar minimum were widely revealed at different longitude sectors, latitudes and local times, which might be explained by the concentration of neutral oxygen, neutral winds, and also the lower atmospheric dynamics.

  5. Composition and structure variation for magnetron sputtered tantalum oxynitride thin films, as function of deposition parameters

    NASA Astrophysics Data System (ADS)

    Cristea, D.; Pătru, M.; Crisan, A.; Munteanu, D.; Crăciun, D.; Barradas, N. P.; Alves, E.; Apreutesei, M.; Moura, C.; Cunha, L.

    2015-12-01

    Tantalum oxynitride thin films were produced by magnetron sputtering. The films were deposited using a pure Ta target and a working atmosphere with a constant N2/O2 ratio. The choice of this constant ratio limits the study concerning the influence of each reactive gas, but allows a deeper understanding of the aspects related to the affinity of Ta to the non-metallic elements and it is economically advantageous. This work begins by analysing the data obtained directly from the film deposition stage, followed by the analysis of the morphology, composition and structure. For a better understanding regarding the influence of the deposition parameters, the analyses are presented by using the following criterion: the films were divided into two sets, one of them produced with grounded substrate holder and the other with a polarization of -50 V. Each one of these sets was produced with different partial pressure of the reactive gases P(N2 + O2). All the films exhibited a O/N ratio higher than the N/O ratio in the deposition chamber atmosphere. In the case of the films produced with grounded substrate holder, a strong increase of the O content is observed, associated to the strong decrease of the N content, when P(N2 + O2) is higher than 0.13 Pa. The higher Ta affinity for O strongly influences the structural evolution of the films. Grazing incidence X-ray diffraction showed that the lower partial pressure films were crystalline, while X-ray reflectivity studies found out that the density of the films depended on the deposition conditions: the higher the gas pressure, the lower the density. Firstly, a dominant β-Ta structure is observed, for low P(N2 + O2); secondly a fcc-Ta(N,O) structure, for intermediate P(N2 + O2); thirdly, the films are amorphous for the highest partial pressures. The comparison of the characteristics of both sets of produced TaNxOy films are explained, with detail, in the text.

  6. Temporal variations in parameters reflecting terminal-electron-accepting processes in an aquifer contaminated with waste fuel and chlorinated solvents

    USGS Publications Warehouse

    McGuire, Jennifer T.; Smith, Erik W.; Long, David T.; Hyndman, David W.; Haack, Sheridan K.; Klug, Michael J.; Velbel, Michael A.

    2000-01-01

    A fundamental issue in aquifer biogeochemistry is the means by which solute transport, geochemical processes, and microbiological activity combine to produce spatial and temporal variations in redox zonation. In this paper, we describe the temporal variability of TEAP conditions in shallow groundwater contaminated with both waste fuel and chlorinated solvents. TEAP parameters (including methane, dissolved iron, and dissolved hydrogen) were measured to characterize the contaminant plume over a 3-year period. We observed that concentrations of TEAP parameters changed on different time scales and appear to be related, in part, to recharge events. Changes in all TEAP parameters were observed on short time scales (months), and over a longer 3-year period. The results indicate that (1) interpretations of TEAP conditions in aquifers contaminated with a variety of organic chemicals, such as those with petroleum hydrocarbons and chlorinated solvents, must consider additional hydrogen-consuming reactions (e.g., dehalogenation); (2) interpretations must consider the roles of both in situ (at the sampling point) biogeochemical and solute transport processes; and (3) determinations of microbial communities are often necessary to confirm the interpretations made from geochemical and hydrogeological measurements on these processes.

  7. Variability of OH rotational temperatures on time scales from hours to 15 years by kinetic temperature variations, emission layer changes, and non-LTE effects

    NASA Astrophysics Data System (ADS)

    Noll, Stefan

    2016-07-01

    Rotational temperatures derived from hydroxyl (OH) line emission are frequently used to study atmospheric temperatures at altitudes of about 87 km. While the measurement only requires intensities of a few bright lines of an OH band, the interpretation can be complicated. Ground-based temperatures are averages for the entire, typically 8 km wide emission layer. Variations in the rotational temperature are then caused by changes of the kinetic temperature and the OH emission profile. The latter can also be accompanied by differences in the layer-averaged efficiency of the thermalisation of the OH rotational level populations. Since this especially depends on the frequency of collisions with O_2, which is low at high altitudes, the non-local thermodynamic equilibrium (non-LTE) contribution to the measured temperatures can be significant and variable. In order to understand the impact of the different sources of OH rotational temperature variations from time scales of hours to a solar cycle, we have studied spectra from the astronomical echelle spectrographs X-shooter and UVES located at Cerro Paranal in Chile. While the X-shooter data spanning 3.5 years allowed us to measure temperatures for 25 OH and two O_2 bands, the UVES spectra cover no more than 10 OH bands simultaneously but a period of about 15 years. These data have been complemented by kinetic temperature and OH and O_2 emission profiles from the multi-channel radiometer SABER on the TIMED satellite. Taking the O_2 and SABER kinetic temperatures as reference and considering the different band-dependent emission profiles, we could evaluate the contribution of non-LTE effects to the measured OH rotational temperatures depending on line set, band, and time. Non-LTE contributions are significant for most bands and can exceed 10 K. The amplitudes of their average nocturnal and seasonal variation are of the order of 1 to 2 K.

  8. Sensitivity analysis of free vibration characteristics of an in situ railway concrete sleeper to variations of rail pad parameters

    NASA Astrophysics Data System (ADS)

    Kaewunruen, Sakdirat; Remennikov, Alex M.

    2006-11-01

    The vibration of in situ concrete sleepers in a railway track structure is a major factor causing cracking of prestressed concrete sleepers and excessive railway track maintenance cost. Not only does the ballast interact with the sleepers, but the rail pads also take part in affecting their free vibration characteristics. This paper presents a sensitivity analysis of free vibration behaviors of an in situ railway concrete sleeper (standard gauge sleeper), incorporating sleeper/ballast interaction, subjected to the variations of rail pad properties. Through finite element analysis, Timoshenko-beam and spring elements were used in the in situ railway concrete sleeper modeling. This model highlights the influence of rail pad parameters on the free vibration characteristics of in situ sleepers. In addition, information on the first five flexural vibration modes indicates the dynamic performance of railway track when using different types of rail pads, as it plays a vital role in the cracking deterioration of concrete sleepers.

  9. Spatio-temporal variations in aerosol optical and cloud parameters over Southern India retrieved from MODIS satellite data

    NASA Astrophysics Data System (ADS)

    Balakrishnaiah, G.; Raghavendra kumar, K.; Suresh Kumar Reddy, B.; Rama Gopal, K.; Reddy, R. R.; Reddy, L. S. S.; Swamulu, C.; Nazeer Ahammed, Y.; Narasimhulu, K.; KrishnaMoorthy, K.; Suresh Babu, S.

    2012-02-01

    Remote sensing of global aerosols has generated a great scientific interest in a variety of applications related to global warming and climate change. The spatial and temporal variations in aerosol particles over Southern India were described in the present study and the impact of these variations on various optical properties of clouds, using Moderate Resolution Imaging Spectroradiometer (MODIS) data retrieved from the Terra satellite. High mean Aerosol Optical Depth (AOD) values were observed in almost all regions during the summer season, whereas in Pune, Visakhapatnam and Hyderabad, high AOD values were noticed during the monsoon season. The Ångström exponent that increases with AOD is opposite to what would be the case if swelling of particles due to hygroscopic growth near cloudy areas played a major role in the MODIS data. We then analyzed the relationships between AOD and four other cloud parameters, namely water vapor (WV), cloud fraction (CF), cloud top temperature (CTT) and cloud top pressure (CTP). Regional correlation maps and time series plots for aerosol (AOD) and cloud parameters were produced to provide a better understanding of aerosol-cloud interaction. The correlation between AOD and CF was greater than 0.51 in Visakhapatnam, 0.45 in Thiruvanantapuram, 0.42 in Pune and whereas in Bangalore, Hyderabad and Anantapur, it is 0.17, 0.39 and 0.12, respectively. The analyses showed strong positive correlations between AOD and WV for all cities investigated. The correlation between AOD and CF was positive for all selected cities. AOD showed a negative correlation with CTP and CTT in Southern Indian regions.

  10. Variations in Quercus sp. pollen seasons (1996-2011) in Poznań, Poland, in relation to meteorological parameters.

    PubMed

    Grewling, Lukasz; Jackowiak, Bogdan; Smith, Matt

    2014-01-01

    The aim of this study is to supply detailed information about oak (Quercus sp.) pollen seasons in Poznań, Poland, based on a 16-year aerobiological data series (1996-2011). The pollen data were collected using a volumetric spore trap of the Hirst design located in Poznań city center. The limits of the pollen seasons were calculated using the 95 % method. The influence of meteorological parameters on temporal variations in airborne pollen was examined using correlation analysis. Start and end dates of oak pollen seasons in Poznań varied markedly from year-to-year (14 and 17 days, respectively). Most of the pollen grains (around 75 % of the seasonal pollen index) were recorded within the first 2 weeks of the pollen season. The tenfold variation was observed between the least and the most intensive pollen seasons. These fluctuations were significantly related to the variation in the sum of rain during the period second fortnight of March to first fortnight of April the year before pollination (r = 0.799; p < 0.001). During the analyzing period, a significant advance in oak pollen season start dates was observed (-0.55 day/year; p = 0.021), which was linked with an increase in the mean temperature during the second half of March and first half of April (+0.2 °C; p = 0.014). Daily average oak pollen counts correlated positively with mean and maximum daily temperatures, and negatively with daily rainfall and daily mean relative humidity. PMID:24817783

  11. The time variations in the parameters of the volumetric strain response to the tidal and baric impacts

    NASA Astrophysics Data System (ADS)

    Cherepantsev, A. S.

    2016-07-01

    The parameters describing the state of the geological medium include its response to the continuous external impacts, which characterizes the structure of the medium and the stresses accumulated in it. In the present paper, through analyzing the long time series of the volumetric strain monitoring data in the nearsurface crustal layer, which were obtained by the American geophysicists under the Plate Boundary Observatory (PBO) project within the Parkfield segment of the San Andreas fault, the time behavior of the volumetric strain response to the separate components of the tides and the air pressure impacts is considered. The analysis of the response regime at the different observational stations suggests a significant influence of the local structural features and tectonic processes at the considered sites of the volumetric strain observations. The estimate of the variations in the partial information from the individual observations (values) is used for improving the reliability of identifying the amplitude peculiarities of the response when synchronizing the variations of the set of the tidal components. It is established that at the PKDLT observation point, a synchronous increase in the transfer coefficient of the tidal impact of the M 2, O 1, and L 2 components two years before the Parkfield earthquake of 2004 took place.

  12. The use of the logarithmic transformation in the calculation of the transport parameters of a system that obeys Michaelis–Menten kinetics

    PubMed Central

    Barber, H. E.; Welch, B. L.; Mackay, D.

    1967-01-01

    1. A logarithmic method is described for the calculation of the transport parameters, Km and Vmax.' of a biological system obeying Michaelis–Menten kinetics. 2. This logarithmic method leads to a way of estimating the transport parameters that has not apparently been used previously. It allows the separation of variance due to Vmax. from other variance, and so reduces the fiducial limits that can be placed on an estimation of Km. 3. The results of studies on the transport of l-histidine and l-monoiodohistidine by rat intestinal sacs in vitro have been used to illustrate the application of the new method. Estimates of the transport parameters have also been made by two alternative procedures. The relative merits of the three methods are discussed. PMID:6033766

  13. Large-scale variations of thermal electron parameters in the solar wind between 0.3 and 1 AU

    NASA Astrophysics Data System (ADS)

    1990-05-01

    Variations of thermal electron parameters in the solar wind are investigated using data obtained from the Helios probes in the years from 1974 to 1976, shortly before solar minimum, at heliocentric distances ranging from 0.3 to 1 AU. The main part of the present analysis is based on Helios 2 data obtained in 1976. Variations across the sector structure of the interplanetary magnetic field (IMF) and across the plasma stream structures are studied. These studies support the hypothesis that the thermal electron properties, i.e., the electron temperatures, the core temperatures, the heat flux, and the normalized heat flux, are strongly correlated with the distance from the neutral sheet in the IMF (implying also a correlation with the plasma stream structures). The results do not indicate significant electron heating in compression regions. Also, power laws for the variations of the electron parameters with distance from the Sun as well as polytrope laws are derived for different solar wind structures and distance ranges. The core temperatures, determined by bi-Maxwellian fits to the electron distributions below 20 or 30 eV, mostly decrease faster with distance from the Sun than the electron temperatures Te∥ and Te⊥, parallel and perpendicular to the magnetic field, respectively, as determined from the entire electron distributions. Most of the Helios 2 observations indicate that the radial profiles of electron temperatures and of electron heat flux tend to be flatter in high-speed streams embedded within the interior of magnetic sectors than in the slow- and intermediate-speed solar wind and in compression regions mostly at or near sector boundaries. For high-speed streams, the Helios data indicate a flattening of the radial profiles for Te⊥ with increasing distance from the Sun. For Te∥ this effect is not as evident in the case of Helios 2 data but is indicated by Helios 1 data. Analogous trends are observed for most of the derived polytrope indices for the

  14. Variation of the Earth tide-seismicity compliance parameter the last 50 years for the seismic area of Evoikos, Greece

    NASA Astrophysics Data System (ADS)

    Contadakis, Michael E.; Arabelos, Demetrious N.; Vergos, George; Spatalas, Spyrous

    2015-04-01

    The results of the analysis of the last 50 years earthquakes series in seismic active areas of Greece, i.e. the areas (a) of the Mygdonian Basin(Contadakis et al. 2007), (b) of the Ionian Islands (Contadakis et al. 2012 ) and (c) of the Hellenic Arc (Vergos et al. 2012 ), indicate that the monthly variation of the frequencies of earthquake occurrence is in accordance with the period of the tidal lunar monthly and semi-monthly (Mm and Mf) variations. The same happens with the corresponding daily variations of the frequencies of earthquake occurrence with the diurnal luni-solar (K1, O1) and semidiurnal lunar (M2) and solar (S2) tidal variations. In addition the confidence level for the identification of such period accordance between earthquakes occurrence frequency and tidal periods varies with seismic activity, i.e. the higher confidence level corresponds to periods with stronger seismic activity. These results are in favor of a tidal triggering process on earthquakes when the stress in the focal area is near the critical level. Based on these results, we consider the confidence level of earthquake frequency of occurrence - tidal period accordance, p, as an index of tectonic stress criticality for earthquake occurrence. A test on posterior of this idea, (i.e. the value of the confidence level index, p, indicate the fault matureness) in the case of the recent seismic activity at Fthiotida, was positive (Contadakis et al 2014). In this paper we present the results of a second test by the occasion of the recent seismic activity of Central Evoikos. The results also are positive. We suggest that this compliance parameter may be used as an additional element for the seismic risk assessment. References Cadicheanu, N., van Ruymbeke, M and Zhu P.,2007:Tidal triggering evidence of intermediate depth earthquakes in Vrancea zone(Romania), NHESS 7,733-740. Contadakis, M. E., Arabelos, D. N., Spatalas, S., 2009, Evidence for tidal triggering on the shallow earthquakes of the

  15. Variation of Ice Crystal Size, Shape and Asymmetry Parameter in Tops of Convective Storm Systems Observed during SEAC4RS

    NASA Astrophysics Data System (ADS)

    van Diedenhoven, B.; Cairns, B.; Fridlind, A. M.; Ackerman, A. S.

    2014-12-01

    The sizes and shapes of ice particles in tops of convective storms have a significant impact on their radiative properties. Ice crystal sizes and shapes likely vary with altitude, environmental conditions and convective strength, but these relationships are not well characterized. The rich dataset of the NASA SEAC4RS field campaign offers unique perspectives to further identify variations of ice crystal sizes and shapes and their relations to environmental and dynamical conditions. Here we focus on data acquired with the Research Scanning Polarimeter (RSP), which was mounted on the high-altitude ER-2 aircraft during SEAC4RS. RSP's unique multi-angular, multi-wavelength total and polarized reflectance measurements allow retrieval of ice effective radius, the aspect ratio of components of ice crystals, the crystal distortion level and ice asymmetry parameter, as well as cloud optical thickness and cloud top height. Using RSP data, as well as data from the eMAS and CPL sensors and in situ probes, we explore the statistical variation of ice properties retrieved during SEAC4RS in tops of convective systems. The data indicates that, in general, ice crystal populations consistent with plate-like components with aspect ratios near 0.4 are prevalent at cloud tops. The asymmetry parameter is around 0.76-0.8 and generally decreases with increasing cloud top height, mainly because the ice crystal distortion increases with height. Below about 12 km height, the effective radius decreases with increasing altitude, as previously shown for convective clouds using satellite data, but at higher levels the SEAC4RS data indicate a transition to effective radii increasing with cloud top height. Here we explore some possible explanations for this transition, related to its approximate coincidence with the level of minimum stability and the homogeneous freezing level, either of which could affect ice crystal formation and evolution. Additionally, we will demonstrate some of the

  16. Site and age class variation of hematologic parameters for female Greater Sage Grouse (Centrocercus urophasianus) of Northern Nevada.

    PubMed

    Dyer, Kathryn J; Perryman, Barry L; Holcombe, Dale W

    2010-01-01

    Decreases in Greater Sage Grouse (Centrocercus urophasianus) numbers throughout the western United States have been attributed to declining habitat quantity and quality. Improving our understanding of how interannual ecologic site variability affects nutritional status and fitness of different bird age classes will lead to improved land management and conservation strategies. Greater Sage Grouse were sampled from two Population Management Units located in northern Nevada, United States: Tuscarora (TU) and Lone Willow (LW) during 15 March-11 April 2004 and 14-20 March 2005. Twenty (16 yearlings, four adults) and 17 (7 yearlings, 10 adults) female Sage Grouse were captured and bled during 2004, and 12 (four yearlings, eight adults) and 14 (10 yearlings, four adults) were sampled during 2005 in TU and LW, respectively. Samples were evaluated to examine the effect of site, age, and year on specific hematologic and serum chemistry parameters. Several differences between age classes, sites, and years were detected for a number of fitness indicators; however, actual values fell within normal ranges of variation for Sage Grouse or other avian species. Differences were also detected for several parameters more closely related to reproductive fitness, including total plasma and serum proteins, and serum calcium and phosphorus. Yearlings had lower plasma protein (P<0.0001) and lower serum protein than did adults (P=0.0003). In 2004, TU yearlings had lower serum calcium levels than the adults, and in 2005, LW yearlings had lower levels than adults (P=0.008). Females on the TU site had lower serum phosphorus than the LW females (P<0.0001). Overall, adult females weighed more than yearlings (P=0.0004). Lower values found in yearlings, and on the TU management unit, indicate a lower production potential, particularly in unfavorable years. A lower intrinsic ability of yearlings to reproduce, combined with lower nutrition potentials and associated annual variations on certain types

  17. Prostate-specific Antigen Density Variation Rate as a Potential Guideline Parameter for Second Prostate Cancer Detection Biopsy

    PubMed Central

    Xie, Gan-Sheng; Lyv, Jin-Xing; Li, Gang; Yan, Chun-Yin; Hou, Jian-Quan; Pu, Jin-Xian; Ding, Xiang; Huang, Yu-Hua

    2016-01-01

    Background: The diagnostic value of current prostate-specific antigen (PSA) tests is challenged by the poor detection rate of prostate cancer (PCa) in repeat prostate biopsy. In this study, we proposed a novel PSA-related parameter named PSA density variation rate (PSADVR) and designed a clinical trial to evaluate its potential diagnostic value for detecting PCa on a second prostate biopsy. Methods: Data from 184 males who underwent second ultrasound-guided prostate biopsy 6 months after the first biopsy were included in the study. The subjects were divided into PCa and non-PCa groups according to the second biopsy pathological results. Prostate volume, PSA density (PSAD), free-total PSA ratio, and PSADVR were calculated according to corresponding formulas at the second biopsy. These parameters were compared using t-test or Mann-Whitney U-test between PCa and non-PCa groups, and receiver operating characteristic analysis were used to evaluate their predictability on PCa detection. Results: PCa was detected in 24 patients on the second biopsy. Mean values of PSA, PSAD, and PSADVR were greater in the PCa group than in the non-PCa group (8.39 μg/L vs. 7.16 μg/L, 0.20 vs. 0.16, 14.15% vs. −1.36%, respectively). PSADVR had the largest area under the curve, with 0.667 sensitivity and 0.824 specificity when the cutoff was 10%. The PCa detection rate was significantly greater in subjects with PSADVR >10% than PSADVR ≤10% (28.6% vs. 6.5%, P < 0.001). In addition, PSADVR was the only parameter in this study that showed a significant correlation with mid-to-high-risk PCa (r = 0.63, P = 0.03). Conclusions: Our results demonstrated that PSADVR improved the PCa detection rate on second biopsies, especially for mid-to-high-risk cancers requiring prompt treatment. PMID:27453228

  18. Determination of kinetic parameters of fermentation processes by a continuous unsteady-state method: Application to the alcoholic fermentation of D-xylose by Pichia stipitis

    SciTech Connect

    Dominguez, H.; Nunez, M.J.; Lema, J.M. ); Chamy, R. )

    1993-05-01

    A quick technique for determination of kinetic parameters of fermentation processes is proposed and applied to the transformation of D-xylose into ethanol by Pichi stipitis. The commonly used method to evaluate these parameters is based on achieving several steady states. In the proposed procedure, [mu][sub m] and K[sub S] can be determined from only one steady state, by provoking a disturbance over it, after allowing the system to return to the original conditions. The main difference between the steady and unsteady state methods is the required fermentation time; while the former method lasted 350 h, the latter required a period 25 times lower. Kinetic and stoichiometric parameters were determined with both methods under anoxic and limited oxygen concentration conditions. Results from the two methods were compared, giving only 2% and 4.5% differences in the values of K[sub S] and [mu][sub m], respectively, under anoxic conditions; 12.5% for K[sub S] and a little over 4% for [mu][sub m] were the deviations under the latter ones.

  19. Assessment and parameter identification of simplified models to describe the kinetics of semi-continuous biomethane production from anaerobic digestion of green and food waste.

    PubMed

    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. PMID:26961220

  20. Determination of pyrolysis kinetic parameters of San Miguel (Texas) lignite. Final report. [650 to 800/sup 0/C; atmospheric pressure

    SciTech Connect

    Mann, U.; Selim, S.; Jih, J.

    1982-06-01

    The thermal decomposition of lignite in the absence of oxygen (pyrolysis) is important as a part of processes for converting lignite to more desirable fuels or for recovery of energy from deep basin lignite. The pyrolysis reaction kinetics of San Miguel (Texas) lignite has been experimentally studied in the temperature range 650 to 800/sup 0/C at atmospheric pressure. Gas and tar produced were collected and measured, and weight change as a function of time was measured. Lignite decomposition into gas, tar, and char can be described by three parallel first order reactions. In the temperature range investigated, the rates of pyrolysis are controlled by intraparticle transport phenomena. A simplified kinetic-transport model was used to estimate the individual reaction rate constants and activation energies. The gas produced was found to consist primarily of carbon dioxide, carbon monoxide, and hydrogen, with some methane, ethane, ethylene, and a trace C/sub 3/ compounds. Sample temperature increases and theoretical calculations indicate that oxygen from the lignite structure may be oxidizing lignite or pyrolysis products. It is recommended that, after suitable equipment modifications, the investigation be extended to study combined oxidation and pyrolysis of lignite.

  1. Phenotypic and genotypic background underlying variations in fatty acid composition and sensory parameters in European bovine breeds

    PubMed Central

    2014-01-01

    Background Consuming moderate amounts of lean red meat as part of a balanced diet valuably contributes to intakes of essential nutrients. In this study, we merged phenotypic and genotypic information to characterize the variation in lipid profile and sensory parameters and to represent the diversity among 15 cattle populations. Correlations between fat content, organoleptic characteristics and lipid profiles were also investigated. Methods A sample of 436 largely unrelated purebred bulls belonging to 15 breeds and reared under comparable management conditions was analyzed. Phenotypic data -including fatness score, fat percentage, individual fatty acids (FA) profiles and sensory panel tests- and genotypic information from 11 polymorphisms was used. Results The correlation coefficients between muscle total lipid measurements and absolute vs. relative amounts of polyunsaturated FA (PUFA) were in opposite directions. Increasing carcass fat leads to an increasing amount of FAs in triglycerides, but at the same time the relative amount of PUFAs is decreasing, which is in concordance with the negative correlation obtained here between the percentage of PUFA and fat measurements, as well as the weaker correlation between total phospholipids and total lipid muscle content compared with neutral lipids. Concerning organoleptic characteristics, a negative correlation between flavour scores and the percentage of total PUFA, particularly to n-6 fraction, was found. The correlation between juiciness and texture is higher than with flavour scores. The distribution of SNPs plotted by principal components analysis (PCA) mainly reflects their known trait associations, although influenced by their specific breed allele frequencies. Conclusions The results presented here help to understand the phenotypic and genotypic background underlying variations in FA composition and sensory parameters between breeds. The wide range of traits and breeds studied, along with the genotypic

  2. Network topology and parameter estimation: from experimental design methods to gene regulatory network kinetics using a community based approach

    PubMed Central

    2014-01-01

    Background Accurate estimation of parameters of biochemical models is required to characterize the dynamics of molecular processes. This problem is intimately linked to identifying the most informative experiments for accomplishing such tasks. While significant progress has been made, effective experimental strategies for parameter identification and for distinguishing among alternative network topologies remain unclear. We approached these questions in an unbiased manner using a unique community-based approach in the context of the DREAM initiative (Dialogue for Reverse Engineering Assessment of Methods). We created an in silico test framework under which participants could probe a network with hidden parameters by requesting a range of experimental assays; results of these experiments were simulated according to a model of network dynamics only partially revealed to participants. Results We proposed two challenges; in the first, participants were given the topology and underlying biochemical structure of a 9-gene regulatory network and were asked to determine its parameter values. In the second challenge, participants were given an incomplete topology with 11 genes and asked to find three missing links in the model. In both challenges, a budget was provided to buy experimental data generated in silico with the model and mimicking the features of different common experimental techniques, such as microarrays and fluorescence microscopy. Data could be bought at any stage, allowing participants to implement an iterative loop of experiments and computation. Conclusions A total of 19 teams participated in this competition. The results suggest that the combination of state-of-the-art parameter estimation and a varied set of experimental methods using a few datasets, mostly fluorescence imaging data, can accurately determine parameters of biochemical models of gene regulation. However, the task is considerably more difficult if the gene network topology is not completely

  3. Evaluation of Thermal Evolution Profiles and Estimation of Kinetic Parameters for Pyrolysis of Coal/Corn Stover Blends Using Thermogravimetric Analysis

    DOE PAGESBeta

    Bhagavatula, Abhijit; Huffman, Gerald; Shah, Naresh; Honaker, Rick

    2014-01-01

    The thermal evolution profiles and kinetic parameters for the pyrolysis of two Montana coals (DECS-38 subbituminous coal and DECS-25 lignite coal), one biomass sample (corn stover), and their blends (10%, 20%, and 30% by weight of corn stover) have been investigated at a heating rate of 5°C/min in an inert nitrogen atmosphere, using thermogravimetric analysis. The thermal evolution profiles of subbituminous coal and lignite coal display only one major peak over a wide temperature distribution, ~152–814°C and ~175–818°C, respectively, whereas the thermal decomposition profile for corn stover falls in a much narrower band than that of the coals, ~226–608°C. Themore » nonlinearity in the evolution of volatile matter with increasing percentage of corn stover in the blends verifies the possibility of synergistic behavior in the blends with subbituminous coal where deviations from the predicted yield ranging between 2% and 7% were observed whereas very little deviations (1%–3%) from predicted yield were observed in blends with lignite indicating no significant interactions with corn stover. In addition, a single first-order reaction model using the Coats-Redfern approximation was utilized to predict the kinetic parameters of the pyrolysis reaction. The kinetic analysis indicated that each thermal evolution profile may be represented as a single first-order reaction. Three temperature regimes were identified for each of the coals while corn stover and the blends were analyzed using two and four temperature regimes, respectively.« less

  4. Errors in Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER) Kinetic Temperature Caused by Non-Local Thermodynamic Equilibrium Model Parameters

    NASA Technical Reports Server (NTRS)

    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.

  5. On the variation of Fourier parameters for Galactic and LMC Cepheids at optical, near-infrared and mid-infrared wavelengths

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Anupam; Kanbur, Shashi M.; Singh, Harinder P.; Macri, Lucas M.; Ngeow, Chow-Choong

    2015-03-01

    We present a light-curve analysis of fundamental-mode Galactic and Large Magellanic Cloud (LMC) Cepheids based on the Fourier decomposition technique. We have compiled light-curve data for Galactic and LMC Cepheids in optical (VI), near-infrared (JHKs) and mid-infrared (3.6 and 4.5 μm) bands from the literature and determined the variation of their Fourier parameters as a function of period and wavelength. We observed a decrease in Fourier amplitude parameters and an increase in Fourier phase parameters with increasing wavelengths at a given period. We also found a decrease in the skewness and acuteness parameters as a function of wavelength at a fixed period. We applied a binning method to analyse the progression of the mean Fourier parameters with period and wavelength. We found that for periods longer than about 20 d, the values of the Fourier amplitude parameters increase sharply for shorter wavelengths as compared to wavelengths longer than the J band. We observed the variation of the Hertzsprung progression with wavelength. The central period of the Hertzsprung progression was found to increase with wavelength in the case of the Fourier amplitude parameters and decrease with increasing wavelength in the case of phase parameters. We also observed a small variation of the central period of the progression between the Galaxy and LMC, presumably related to metallicity effects. These results will provide useful constraints for stellar pulsation codes that incorporate stellar atmosphere models to produce Cepheid light curves in various bands.

  6. Applying thermodynamic and kinetic parameters to predict the physical stability of two differently prepared amorphous forms of simvastatin.

    PubMed

    Graeser, Kirsten A; Patterson, James E; Rades, Thomas

    2009-08-01

    Converting drugs from the crystalline to the amorphous state has gained increasing interest in the past decades as a potential method to overcome solubility issues of poorly water soluble drugs. A variety of techniques exist to convert the crystalline state of a drug to its amorphous form, including solution based, heat based and solid - solid conversion based methods. Inherent to the amorphous state, regardless of its preparation technique, is its physical instability and tendency to recrystallize. In this study, quench-cooled and cryo-milled simvastatin were compared with regards to their configurational thermodynamic parameters (entropy, enthalpy and Gibbs free energy) and mobility (relaxation times calculated using the Adam-Gibbs and Kohlrausch-Williams-Watts method). Stability studies showed quench-cooled simvastatin to be more stable than cryo-milled simvastatin. This was reflected in the calculated parameters although their absolute values did not agree with the stability behaviour. Relaxation time parameters of tau = 6.9 x 10(4) s for quench-cooled and tau = 1.7 x 10(4) s for cryo-milled simvastatin were calculated. The results from this study suggested that differences in the physical stability of amorphous forms prepared by different techniques are reflected in their mobility and thermodynamic parameters. Even though the predictive capabilities of these parameters for a set of different drugs may be limited, they can serve as a predictive tool for physical stability assessment if differently prepared amorphous forms of the same drug are investigated. PMID:19534709

  7. Assessment of Wall Elasticity Variations on Intraluminal Haemodynamics in Descending Aortic Dissections Using a Lumped-Parameter Model

    PubMed Central

    Rudenick, Paula A.; Bijnens, Bart H.; Segers, Patrick; García-Dorado, David; Evangelista, Arturo

    2015-01-01

    Descending aortic dissection (DAD) is associated with high morbidity and mortality rates. Aortic wall stiffness is a variable often altered in DAD patients and potentially involved in long-term outcome. However, its relevance is still mostly unknown. To gain more detailed knowledge of how wall elasticity (compliance) might influence intraluminal haemodynamics in DAD, a lumped-parameter model was developed based on experimental data from a pulsatile hydraulic circuit and validated for 8 clinical scenarios. Next, the variations of intraluminal pressures and flows were assessed as a function of wall elasticity. In comparison with the most rigid-wall case, an increase in elasticity to physiological values was associated with a decrease in systolic and increase in diastolic pressures of up to 33% and 63% respectively, with a subsequent decrease in the pressure wave amplitude of up to 86%. Moreover, it was related to an increase in multidirectional intraluminal flows and transition of behaviour as 2 parallel vessels towards a vessel with a side-chamber. The model supports the extremely important role of wall elasticity as determinant of intraluminal pressures and flow patterns for DAD, and thus, the relevance of considering it during clinical assessment and computational modelling of the disease. PMID:25881158

  8. A study of variation in accretion disk parameters with phases of `heartbeats' in IGR J17091-3624

    NASA Astrophysics Data System (ADS)

    Rao, Anjali; Vadawale, Santosh V.

    The standard accretion disk model is based on a famous Shakura-Sunyaev viscosity prescription in which viscous stress is scaled with total pressure. Though the model has been very successful to explain various properties of accretion disk, it was known that Shakura-Sunyaev disk is inherently unstable in the radiation pressure dominated inner accretion disk region, particularly when local mass accretion rate is high. This instability, known as radiation pressure instability (RPI), is expected to give rise to a limit cycle behavior in which source may exhibit a series of quasi-periodic bursts. So far such behavior, popularly known as `heartbeats' was observed only in GRS 1915+105. Recently, IGR J17091-3624, a transient black hole candidate, became the second source showing 'heartbeat' type variability during its last outburst in 2011. Here we carry out a comparative study of the variation of accretion disk parameters during such variability in both IGR J17091-3624 and GRS 1915+105. We find that the radiation pressure instability alone may not be sufficient to explain the observed spectral variability in both the sources.

  9. Assessment of wall elasticity variations on intraluminal haemodynamics in descending aortic dissections using a lumped-parameter model.

    PubMed

    Rudenick, Paula A; Bijnens, Bart H; Segers, Patrick; García-Dorado, David; Evangelista, Arturo

    2015-01-01

    Descending aortic dissection (DAD) is associated with high morbidity and mortality rates. Aortic wall stiffness is a variable often altered in DAD patients and potentially involved in long-term outcome. However, its relevance is still mostly unknown. To gain more detailed knowledge of how wall elasticity (compliance) might influence intraluminal haemodynamics in DAD, a lumped-parameter model was developed based on experimental data from a pulsatile hydraulic circuit and validated for 8 clinical scenarios. Next, the variations of intraluminal pressures and flows were assessed as a function of wall elasticity. In comparison with the most rigid-wall case, an increase in elasticity to physiological values was associated with a decrease in systolic and increase in diastolic pressures of up to 33% and 63% respectively, with a subsequent decrease in the pressure wave amplitude of up to 86%. Moreover, it was related to an increase in multidirectional intraluminal flows and transition of behaviour as 2 parallel vessels towards a vessel with a side-chamber. The model supports the extremely important role of wall elasticity as determinant of intraluminal pressures and flow patterns for DAD, and thus, the relevance of considering it during clinical assessment and computational modelling of the disease. PMID:25881158

  10. Crystal Growth Simulations To Establish Physically Relevant Kinetic Parameters from the Empirical Kolmogorov-Johnson-Mehl-Avrami Model

    SciTech Connect

    Dill, Eric D.; Folmer, Jacob C.W.; Martin, James D.

    2013-12-05

    A series of simulations was performed to enable interpretation of the material and physical significance of the parameters defined in the Kolmogorov, Johnson and Mehl, and Avrami (KJMA) rate expression commonly used to describe phase boundary controlled reactions of condensed matter. The parameters k, n, and t0 are shown to be highly correlated, which if unaccounted for seriously challenge mechanistic interpretation. It is demonstrated that rate measurements exhibit an intrinsic uncertainty without precise knowledge of the location and orientation of nucleation with respect to the free volume into which it grows. More significantly, it is demonstrated that the KJMA rate constant k is highly dependent on sample size. However, under the simulated conditions of slow nucleation relative to crystal growth, sample volume and sample anisotropy correction affords a means to eliminate the experimental condition dependence of the KJMA rate constant, k, producing the material-specific parameter, the velocity of the phase boundary, vpb.

  11. Variation in Mutation Rates Caused by RB69pol Fidelity Mutants Can Be Rationalized on the Basis of Their Kinetic Behavior and Crystal Structures

    SciTech Connect

    S Xia; M Wang; H Lee; A Sinha; G Blaha; T Christian; J Wang; W Konigsberg

    2011-12-31

    We have previously observed that stepwise replacement of amino acid residues in the nascent base-pair binding pocket of RB69 DNA polymerase (RB69pol) with Ala or Gly expanded the space in this pocket, resulting in a progressive increase in misincorporation. However, in vivo results with similar RB69pol nascent base-pair binding pocket mutants showed that mutation rates, as determined by the T4 phage rI forward assay and rII reversion assay, were significantly lower for the RB69pol S565G/Y567A double mutant than for the Y567A single mutant, the opposite of what we would have predicted. To investigate the reasons for this unexpected result, we have determined the pre-steady-state kinetic parameters and crystal structures of relevant ternary complexes. We found that the S565G/Y567A mutant generally had greater base selectivity than the Y567A mutant and that the kinetic parameters for dNMP insertion, excision of the 3'-terminal nucleotide residue, and primer extension beyond a mispair differed not only between these two mutants but also between the two highly mutable sequences in the T4 rI complementary strand. Comparison of the crystal structures of these two mutants with correct and incorrect incoming dNTPs provides insight into the unexpected increase in the fidelity of the S565G/Y567A double mutant. Taken together, the kinetic and structural results provide a basis for integrating and interpreting in vivo and in vitro observations.

  12. Temporal and spatial variations in photosynthetic parameters in the South Sea and East/Japan Sea, Korea

    NASA Astrophysics Data System (ADS)

    Lee, J.

    2015-12-01

    Although the photosynthetic parameters are important factors for phytoplankton ecology and simulation models of ecological dynamics in marine ecosystems, very limited data for temporal and spatial variations in in situ photosynthetic parameters are available in Korean oceans. To obtain the photosynthetic parameters, we measured carbon fixation rates of phytoplankton from six light depths (100, 50, 30, 12, 5, and 1 %) at 2 sampling sites (Hupo-Pohang and Gwangyang bay, Korea) in 2013, using a stable carbon isotope (13C) tracer technique. Based on the results from this study, the ranges of α (photosynthetic efficiency), β (strength of the photoinhibition) and μ (growth rate) were 0.06-0.07 mg C h-1 (µmol quanta m-2 s-1) -1, 3.90-21.41 mg C h-1 (µmol quanta m-2 s-1) -1, and 0.18-0.19 d-1, respectively at Hupo-Pohang site in the East/Japan Sea. The values of α and β were higher in November (Average ± S.D = 0.07±0.02 mg C h-1 (µmol quanta m-2 s-1) -1 and 21.41±36.89 mg C h-1 (µmol quanta m-2 s-1) -1, respectvitly) than those (Average ± S.D = 0.06±0.05 mg C h-1 (µmol quanta m-2 s-1) -1 and 3.90±5.36 mg C h-1 (µmol quanta m-2 s-1) -1, respectively) in September, 2013. In contrast, μ value was higher in September (Average ± S.D = 0.19±0.15 d-1) than that (Average ± S.D = 0.18±0.14 d-1) in November. In comparison, the ranges of α, β and μ at Gwangyang bay site in the South Sea were 0.05-0.11 mg C h-1 mg C h-1 (µmol quanta m-2 s-1) -1 , 3.14-93.91 mg C h-1 (µmol quanta m-2 s-1) -1 and 0.14-0.34 d-1, respectively. The parameters of α and μ were highest in June (Average ± S.D = 0.11±0.05 mg C h-1 (µmol quanta m-2 s-1) -1, and 0.34±0.27 d-1), and β was highest value in January (Average ± S.D = 93.31±81.47 mg C h-1 (µmol quanta m-2 s-1) -1). The photosynthetic parameters obtained in this study are within the ranges of α (0.08 to 0.26 mg C h-1 (µmol quanta m-2 s-1) -1) and μ (0.42 to 1.31 d-1) in Bedford basin previously reported by Brenda

  13. Microbial maximal specific growth rate as a square-root function of biomass yield and two kinetic parameters.

    PubMed

    Wong, Wilson W; Liao, James C

    2009-11-01

    Understanding how growth rates changes under different perturbations is fundamental to many aspect of microbial physiology. In this work, we experimentally showed that maximal specific growth rate is a square-root function of the biomass yield, the substrate turnover number, and the maximum synthesis rate of the substrate transporter under that condition. We used Escherichia coli cultures in lactose minimal medium as a model system by introducing genetic modifications, in vitro evolution, and ethanol stress to the cell. Deletion of crr affected all three parameters in different directions while deletion of ptsG decreased only the biomass yield. Ethanol stress negatively impacted all three parameters, while anaerobicity decreased biomass yield and transporter synthesis rate. In addition, laboratory evolution increased the growth rate in lactose mostly through enhancing the expression rate of the lac operon. Despite all these changes, the growth rate of the perturbed strain was successfully related to the three parameters by the square-root equation. Thus, this square-root relationship provides insight into how growth rate is altered by different physiological parameters. PMID:19712746

  14. Kinetic Parameters of Secondary Carbide Precipitation in High-Cr White Iron Alloyed by Mn-Ni-Mo-V Complex

    NASA Astrophysics Data System (ADS)

    Efremenko, V. G.; Chabak, Yu. G.; Brykov, M. N.

    2013-05-01

    This study presents kinetics of precipitation of secondary carbides in 14.55%Cr-Mn-Ni-Mo-V white cast iron during the destabilization heat treatment. The as-cast iron was heat treated at temperatures in the range of 800-1100 °C with soaking up to 6 h. Investigation was carried out by optical and electron microscopy, dilatometric analysis, Ms temperature measurement, and bulk hardness evaluation. TTT-curve of precipitation process of secondary carbides (M7C3, M23C6, M3C2) has been constructed in this study. It was determined that the precipitation occurs at the maximum rate at 950 °C where the process is started after 10 s and completed within 160 min further. The precipitation leads to significant increase of Ms temperature and bulk hardness; large soaking times at destabilization temperatures cause coarsening of secondary carbides and decrease in particles number, followed by decrease in hardness. The results obtained are discussed in terms of solubility of carbon in the austenite and diffusion activation of Cr atoms. The precipitation was found to consist of two stages with activation energies of 196.5 kJ/g-mole at the first stage and 47.1 kJ/g-mole at the second stage.

  15. A protocol for the measurement of all the parameters of the mass transfer kinetics in columns used in liquid chromatography

    SciTech Connect

    Gritti, Fabrice; Guiochon, Georges A

    2010-01-01

    Band broadening in chromatography results from the combination of the dispersive effects that are associated with the different steps involved in the migration of compound bands along the column. These steps include longitudinal diffusion, trans-particle mass transfer, external film mass transfer, overall eddy diffusion, including trans-column, short-range inter-channel, trans-channel eddy diffusion, and the possible, additional mass transfer contributions arising from heat friction and the thermal heterogeneity of the column. We describe a series of experiments that provide the data needed to determine the coefficients of the contributions to band broadening of each one of these individual mass transfer steps. This specifically designed protocol can provide key information regarding the kinetic performance of columns used in liquid chromatography and explain why different columns behave so differently. The limitations, accuracy and precision of these methods are discussed. Further avenues of research that could improve the characterization of the mass transfer mechanisms in chromatographic columns, possibly contributing to the development of better columns, are suggested.

  16. Relationship Between the Structure Parameters of a Solid Body and the Kinetics of Donor-Acceptor Interaction in Heterogeneous Systems

    NASA Astrophysics Data System (ADS)

    Khentov, V. Ya.; Khussein, Kh. Kh.

    2016-05-01

    Interaction of an organic ligand molecule with the surface of a d-metal or of disperse particles of chemical compounds containing covalent bonds in a nonaqueous solvent (direct synthesis of complex compounds) is determined by the structure parameters of the solid body. The relationships of the rate and energy of activation of the donor-acceptor interaction of the metal with the Grüneisen coefficient and the Debye temperature of the metal have been established.

  17. Relationship Between the Structure Parameters of a Solid Body and the Kinetics of Donor-Acceptor Interaction in Heterogeneous Systems

    NASA Astrophysics Data System (ADS)

    Khentov, V. Ya.; Khussein, Kh. Kh.

    2016-06-01

    Interaction of an organic ligand molecule with the surface of a d-metal or of disperse particles of chemical compounds containing covalent bonds in a nonaqueous solvent (direct synthesis of complex compounds) is determined by the structure parameters of the solid body. The relationships of the rate and energy of activation of the donor-acceptor interaction of the metal with the Grüneisen coefficient and the Debye temperature of the metal have been established.

  18. Quality changes of pasteurised orange juice during storage: A kinetic study of specific parameters and their relation to colour instability.

    PubMed

    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. PMID:25977009

  19. Effects of organic ligands and temperature variations on the kinetics of olivine carbonation and the formation of associated secondary phases

    NASA Astrophysics Data System (ADS)

    Sissmann, O.; Daval, D.; Martinez, I.; Brunet, F.; Verlaguet, A.; Pinquier, Y.; Guyot, F. J.

    2011-12-01

    The slow dissolution kinetics of Mg-rich silicates has become a critical issue for the geologic CO2 sequestration in basic rocks. Previous batch carbonation studies on San Carlos olivine [1] performed in CO2 saturated water (at 90°C and P CO2 = 280 bar) have focused on the role that secondary phases, such as amorphous silica layers (SiO2 (am)), have on the transport of reactants from and to the reactive surfaces. The fluid composition remained roughly constant over the duration of the experiment, close to saturation with respect to amorphous silica and with a [Mg2+]/[SiO2 (aq)] ratio close to stoechiometric release, suggesting a passivation of the olivine surface by the silica layer. In order to accelerate the dissolution process, organic ligands such as citrate and acetate were added to the solutions and tested at 1M and 0.1M concentrations in similar batch experiments. An intrinsic increase of the dissolution rate of olivine was expected [2], [3] prior to the formation of a passivating silica layer. Preliminary results confirm this idea since Mg was released in non-stoechimoetric proportions with respect to SiO2 (aq) (found to be in equilibrium with SiO2 (am)). Similarly, a slight increase of temperature (from 90°C to 120°C) accelerated the reaction kinetics as well, possibly impacting the textural properties of SiO2 (am). Current TEM investigations are directed to confirming a possible link between the observed increase of the rate and textural properties of secondary phases. In addition, because carbonate minerals have a retrograde solubility, thermodynamical modelling suggests that this temperature increase should allow the fluid to reach saturation with respect to carbonates before reaching saturation with respect to SiO2 (am). Enough Mg can therefore be released to initiate the formation of carbonates before the silica precipitates and passivates the olivine surface. [1] Daval et al (2011), Chemical Geology, v.284, p.193-209 [2] Grandstaff, D.E. (1986) In

  20. Insights on the development, kinetics, and variation of photoinhibition using chlorophyll fluorescence imaging of a chilled, variegated leaf.

    PubMed

    Hogewoning, Sander W; Harbinson, Jeremy

    2007-01-01

    The effect of chilling on photosystem II (PSII) efficiency was studied in the variegated leaves of Calathea makoyana, in order to gain insight into the causes of chilling-induced photoinhibition. Additionally, a relationship was revealed between (chilling) stress and variation in photosynthesis. Chilling treatments (5 degrees C and 10 degrees C) were performed for different durations (1-7 d) under a moderate irradiance (120 micromol m-2 s-1). The individual leaves were divided into a shaded zone and two illuminated, chilled zones. The leaf tip and sometimes the leaf base were not chilled. Measurements of the dark-adapted Fv/Fm were made on the different leaf zones at the end of the chilling treatment, and then for several days thereafter to monitor recovery. Chilling up to 7 d in the dark did not affect PSII efficiency and visual appearance, whereas chilling in the light caused severe photoinhibition, sometimes followed by leaf necrosis. Photoinhibition increased with the duration of the chilling period, whereas, remarkably, chilling temperature had no effect. In the unchilled leaf tip, photoinhibition also occurred, whereas in the unchilled leaf base it did not. Whatever the leaf zone, photoinhibition became permanent if the mean value dropped below 0.4, although chlorosis and necrosis were associated solely with chilled illuminated tissue. Starch accumulated in the unchilled leaf tip, in contrast to the adjacent chilled irradiated zone. This suggests that photoinhibition was due to a secondary effect in the unchilled leaf tip (sink limitation), whereas it was a direct effect of chilling and irradiance in the chilled illuminated zones. The PSII efficiency and its coefficient of variation showed a unique negative linearity across all leaf zones and different tissue types. The slope of this curve was steeper for chilled leaves than it was for healthy, non-stressed leaves, suggesting that the coefficient of variation may be an important tool for assessing stress in

  1. Estimation of shear velocity contrast for dipping or anisotropic medium from transmitted Ps amplitude variation with ray-parameter

    NASA Astrophysics Data System (ADS)

    Kumar, Prakash

    2015-12-01

    Amplitude versus offset analysis of P to P reflection is often used in exploration seismology for hydrocarbon exploration. In the present work, the feasibility to estimate crustal velocity structure from transmitted P to S wave amplitude variation with ray-parameter has been investigated separately for dipping layer and anisotropy medium. First, for horizontal and isotropic medium, the approximation of P-to-s conversion is used that is expressed as a linear form in terms of slowness. Next, the intercept of the linear regression has been used to estimate the shear wave velocity contrast (δβ) across an interface. The formulation holds good for isotropic and horizontal layer medium. Application of such formula to anisotropic medium or dipping layer data may lead to erroneous estimation of δβ. In order to overcome this problem, a method has been proposed to compensate the SV-amplitude using shifted version of SH-amplitude, and subsequently transforming SV amplitudes equivalent to that from isotropic or horizontal layer medium as the case may be. Once this transformation has been done, δβ can be estimated using isotropic horizontal layer formula. The shifts required in SH for the compensation are π/2 and π/4 for dipping layer and anisotropic medium, respectively. The effectiveness of the approach has been reported using various synthetic data sets. The methodology is also tested on real data from HI-CLIMB network in Himalaya, where the presence of dipping Moho has already been reported. The result reveals that the average shear wave velocity contrast across the Moho is larger towards the Indian side compared to the higher Himalayan and Tibetan regions.

  2. Reversible dioxygen binding and arene hydroxylation reactions: Kinetic and thermodynamic studies involving ligand electronic and structural variations

    PubMed Central

    Karlin, Kenneth D.; Zhang, Christiana Xin; Rheingold, Arnold L.; Galliker, Benedikt; Kaderli, Susan; Zuberbühler, Andreas D.

    2012-01-01

    Copper-dioxygen interactions are of intrinsic importance in a wide range of biological and industrial processes. Here, we present detailed kinetic/thermodynamic studies on the O2-binding and arene hydroxylation reactions of a series of xylyl-bridged binuclear copper(I) complexes, where the effects of ligand electronic and structural elements on these reactions are investigated. Ligand 4-pyridyl substituents influence the reversible formation of side-on bound μ-η2:η2-peroxodicopper(II) complexes, with stronger donors leading to more rapid formation and greater thermodynamic stability of product complexes [CuII2(RXYL)(O22−)]2+. An interaction of the latter with the xylyl π-system is indicated. Subsequent peroxo electrophilic attack on the arene leads to C–H activation and oxygenation with hydroxylated products [CuII2(RXYLO2−)(−OH)]2+ being formed. A related unsymmetrical binucleating ligand was also employed. Its corresponding O2-adduct [CuII2(UN)(O22−)]2+ is more stable, but primarily because the subsequent decay by hydroxylation is in a relative sense slower. The study emphasizes how ligand electronic effects can and do influence and tune copper(I)–dioxygen complex formation and subsequent reactivity. PMID:23420124

  3. Structural characterization, thermoluminescence studies and kinetic parameters of SrSO4:Eu nanophosphors under X-ray and gamma excitations.

    PubMed

    Jayasudha, S; Madhukumar, K; Nair, C M K; Nair, Resmi G; Anandakumar, V M; Elias, Thayal Singh

    2016-02-15

    Nanostructured SrSO4:Eu phosphors with high thermoluminescence (TL) emission temperatures have been synthesized through a controlled chemical precipitation method. Structural analysis and TL studies under both γ-ray and X-ray excitations were done. The phosphors were characterized using Powder X-ray diffraction, X-ray photoelectron spectroscopy, SEM, TEM, thermogravimetry, UV-VIS and photoluminescence studies. The average crystallite size estimated using PXRD data is found to be around 40nm. XPS and PL studies reveal that Eu(2+) ions are the luminescence emission centres in the phosphor. The phosphor is found to be highly TL sensitive to both γ-rays and X-rays with very high emission temperature which is not reported so far. The emission behaviour is suitable for environmental radiation dosimetry applications. The TL glow curve shows well-defined isolated high temperature emission peak at 312°C under 2Gy γ-excitation and 284°C for low energy diagnostic X-ray irradiation and 271°C for high energy therapeutic X-rays. Chen's peak shape method is applied to obtain the kinetic parameters behind the TL emission. The TL mechanism is found to follow second order kinetics, suggesting the probability of re-trapping of charge carriers. PMID:26562181

  4. Structural characterization, thermoluminescence studies and kinetic parameters of SrSO4:Eu nanophosphors under X-ray and gamma excitations

    NASA Astrophysics Data System (ADS)

    Jayasudha, S.; Madhukumar, K.; Nair, C. M. K.; Nair, Resmi G.; Anandakumar, V. M.; Elias, Thayal Singh

    2016-02-01

    Nanostructured SrSO4:Eu phosphors with high thermoluminescence (TL) emission temperatures have been synthesized through a controlled chemical precipitation method. Structural analysis and TL studies under both γ-ray and X-ray excitations were done. The phosphors were characterized using Powder X-ray diffraction, X-ray photoelectron spectroscopy, SEM, TEM, thermogravimetry, UV-VIS and photoluminescence studies. The average crystallite size estimated using PXRD data is found to be around 40 nm. XPS and PL studies reveal that Eu2 + ions are the luminescence emission centres in the phosphor. The phosphor is found to be highly TL sensitive to both γ-rays and X-rays with very high emission temperature which is not reported so far. The emission behaviour is suitable for environmental radiation dosimetry applications. The TL glow curve shows well-defined isolated high temperature emission peak at 312 °C under 2 Gy γ-excitation and 284 °C for low energy diagnostic X-ray irradiation and 271 °C for high energy therapeutic X-rays. Chen's peak shape method is applied to obtain the kinetic parameters behind the TL emission. The TL mechanism is found to follow second order kinetics, suggesting the probability of re-trapping of charge carriers.

  5. A structured model for simulation of cultures of the cyanobacterium Spirulina platensis in photobioreactors: II. Identification of kinetic parameters under light and mineral limitations.

    PubMed

    Cornet, J F; Dussap, C G; Cluzel, P; Dubertret, G

    1992-10-01

    A structured model for the culture of cyanobacteria in photobioreactors is developed on the basis of Schuster's approximations for radiative light transfer. This model is therefore limited to monodimensional geometries and kinetic aspects.Light-harvesting pigments play a crucial role in defining the profile of radiative transfer inside the culture medium and in controlling the metabolism, particularly the metabolic deviations induced by mineral limitations. Modeling therefore requires the biomass to be divided into several compartments, among which the light-harvesting compartment allows a working illuminated volume to be defined within the photobioreactor. This volume may change during batch cultures, largely decreasing as pigment concentration increases during growth but increasing as pigments are consumed during mineral limitation. This approach enables, in photobioreactors of simple parallelepipedic, geometries, kinetic parameters to be determined with high accuracy; this may then be extended to vessels of more complex geometries, such as cylindrical photobioreactors.The model is applied to controlled batch cultures of the cyanobacterium Spirulina platensis in parallelepipedic photobioreactors to assess its ability to predict the behavior of these microorganisms in conditions of light and mineral limitations. Results allowed the study of optimal operating condition for continuous cultures to be approached. PMID:18601186

  6. Isotherm Modelling, Kinetic Study and Optimization of Batch Parameters Using Response Surface Methodology for Effective Removal of Cr(VI) Using Fungal Biomass

    PubMed Central

    Chidambaram, Ramalingam

    2015-01-01

    Biosorption is a promising alternative method to replace the existing conventional technique for Cr(VI) removal from the industrial effluent. In the present experimental design, the removal of Cr(VI) from the aqueous solution was studied by Aspergillus niger MSR4 under different environmental conditions in the batch systems. The optimum conditions of biosorption were determined by investigating pH (2.0) and temperature (27°C). The effects of parameters such as biomass dosage (g/L), initial Cr(VI) concentration (mg/L) and contact time (min) on Cr(VI) biosorption were analyzed using a three parameter Box–Behnken design (BBD). The experimental data well fitted to the Langmuir isotherm, in comparison to the other isotherm models tested. The results of the D-R isotherm model suggested that a chemical ion-exchange mechanism was involved in the biosorption process. The biosorption process followed the pseudo-second-order kinetic model, which indicates that the rate limiting step is chemisorption process. Fourier transform infrared (FT-IR) spectroscopic studies revealed the possible involvement of functional groups, such as hydroxyl, carboxyl, amino and carbonyl group in the biosorption process. The thermodynamic parameters for Cr(VI) biosorption were also calculated, and the negative ∆Gº values indicated the spontaneous nature of biosorption process. PMID:25786227

  7. Model of 2,3-bisphosphoglycerate metabolism in the human erythrocyte based on detailed enzyme kinetic equations: equations and parameter refinement.

    PubMed

    Mulquiney, P J; Kuchel, P W

    1999-09-15

    Over the last 25 years, several mathematical models of erythrocyte metabolism have been developed. Although these models have identified the key features in the regulation and control of erythrocyte metabolism, many important aspects remain unexplained. In particular, none of these models have satisfactorily accounted for 2,3-bisphosphoglycerate (2,3-BPG) metabolism. 2,3-BPG is an important modulator of haemoglobin oxygen affinity, and hence an understanding of the regulation of 2,3-BPG concentration is important for understanding blood oxygen transport. A detailed, comprehensive, and hence realistic mathematical model of erythrocyte metabolism is presented that can explain the regulation and control of 2,3-BPG concentration and turnover. The model is restricted to the core metabolic pathways, namely glycolysis, the 2,3-BPG shunt and the pentose phosphate pathway (PPP), and includes membrane transport of metabolites, the binding of metabolites to haemoglobin and Mg(2+), as well as pH effects on key enzymic reactions and binding processes. The model is necessarily complex, since it is intended to describe the regulation and control of 2,3-BPG metabolism under a wide variety of physiological and experimental conditions. In addition, since H(+) and blood oxygen tension are important external effectors of 2,3-BPG concentration, it was important that the model take into account the large array of kinetic and binding phenomena that result from changes in these effectors. Through an iterative loop of experimental and simulation analysis many values of enzyme-kinetic parameters of the model were refined to yield close conformity between model simulations and 'real' experimental data. This iterative process enabled a single set of parameters to be found which described well the metabolic behaviour of the erythrocyte under a wide variety of conditions. PMID:10477269

  8. Model of 2,3-bisphosphoglycerate metabolism in the human erythrocyte based on detailed enzyme kinetic equations: equations and parameter refinement.

    PubMed Central

    Mulquiney, P J; Kuchel, P W

    1999-01-01

    Over the last 25 years, several mathematical models of erythrocyte metabolism have been developed. Although these models have identified the key features in the regulation and control of erythrocyte metabolism, many important aspects remain unexplained. In particular, none of these models have satisfactorily accounted for 2,3-bisphosphoglycerate (2,3-BPG) metabolism. 2,3-BPG is an important modulator of haemoglobin oxygen affinity, and hence an understanding of the regulation of 2,3-BPG concentration is important for understanding blood oxygen transport. A detailed, comprehensive, and hence realistic mathematical model of erythrocyte metabolism is presented that can explain the regulation and control of 2,3-BPG concentration and turnover. The model is restricted to the core metabolic pathways, namely glycolysis, the 2,3-BPG shunt and the pentose phosphate pathway (PPP), and includes membrane transport of metabolites, the binding of metabolites to haemoglobin and Mg(2+), as well as pH effects on key enzymic reactions and binding processes. The model is necessarily complex, since it is intended to describe the regulation and control of 2,3-BPG metabolism under a wide variety of physiological and experimental conditions. In addition, since H(+) and blood oxygen tension are important external effectors of 2,3-BPG concentration, it was important that the model take into account the large array of kinetic and binding phenomena that result from changes in these effectors. Through an iterative loop of experimental and simulation analysis many values of enzyme-kinetic parameters of the model were refined to yield close conformity between model simulations and 'real' experimental data. This iterative process enabled a single set of parameters to be found which described well the metabolic behaviour of the erythrocyte under a wide variety of conditions. PMID:10477269

  9. Quantification of Kinetic Rate Law Parameters of Uranium Release from Sodium Autunite as a Function of Aqueous Bicarbonate Concentrations

    SciTech Connect

    Gudavalli, Ravi; Katsenovich, Yelena; Wellman, Dawn M.; Lagos, Leonel; Tansel, Berrin

    2013-09-05

    ABSTRACT: Hydrogen carbonate is one of the most significant components within the uranium geochemical cycle. In aqueous solutions, hydrogen carbonate forms strong complexes with uranium. As such, aqueous bicarbonate may significantly increase the rate of uranium release from uranium minerals. Quantifying the relationship of aqueous hydrogen carbonate solutions to the rate of uranium release during dissolution is critical to understanding the long-term fate of uranium within the environment. Single-pass flow-through (SPTF) experiments were conducted to estimate the rate of uranium release from Na meta-autunite as a function of bicarbonate solutions (0.0005-0.003 M) under the pH range of 6-11 and temperatures of 5-60oC. Consistent with the results of previous investigation, the rate of uranium release from sodium autunite exhibited minimal dependency on temperature; but were strongly dependent on pH and increasing concentrations of bicarbonate solutions. Most notably at pH 7, the rate of uranium release exhibited 370 fold increases relative to the rate of uranium release in the absence of bicarbonate. However, the effect of increasing concentrations of bicarbonate solutions on the release of uranium was significantly less under higher pH conditions. It is postulated that at high pH values, surface sites are saturated with carbonate, thus the addition of more bicarbonate would have less effect on uranium release. Results indicate the activation energies were unaffected by temperature and bicarbonate concentration variations, but were strongly dependent on pH conditions. As pH increased from 6 to 11, activation energy values were observed to decrease from 29.94 kJ mol-1 to 13.07 kJ mol-1. The calculated activation energies suggest a surface controlled dissolution mechanism.

  10. Kinetic model framework for aerosol and cloud surface chemistry and gas-particle interactions: Part 1 - general equations, parameters, and terminology

    NASA Astrophysics Data System (ADS)

    Pöschl, U.; Rudich, Y.; Ammann, M.

    2005-04-01

    Aerosols and clouds play central roles in atmospheric chemistry and physics, climate, air pollution, and public health. The mechanistic understanding and predictability of aerosol and cloud properties, interactions, transformations, and effects are, however, still very limited. This is due not only to the limited availability of measurement data, but also to the limited applicability and compatibility of model formalisms used for the analysis, interpretation, and description of heterogeneous and multiphase processes. To support the investigation and elucidation of atmospheric aerosol and cloud surface chemistry and gas-particle interactions, we present a comprehensive kinetic model framework with consistent and unambiguous terminology and universally applicable rate equations and parameters. It allows to describe mass transport and chemical reactions at the gas-particle interface and to link aerosol and cloud surface processes with gas phase and particle bulk processes in systems with multiple chemical components and competing physicochemical processes. The key elements and essential aspects of the presented framework are: a simple and descriptive double-layer surface model (sorption layer and quasi-static layer); straightforward flux-based mass balance and rate equations; clear separation of mass transport and chemical reactions; well-defined rate parameters (uptake and accommodation coefficients, reaction and transport rate coefficients); clear distinction between gas phase, gas-surface, and surface-bulk transport (gas phase diffusion correction, surface and bulk accommodation); clear distinction between gas-surface, surface layer, and surface-bulk reactions (Langmuir-Hinshelwood and Eley-Rideal mechanisms); mechanistic description of concentration and time dependencies; flexible inclusion/omission of chemical species and physicochemical processes; flexible convolution/deconvolution of species and processes; and full compatibility with traditional resistor model

  11. Analysis of the energetic metabolism in cyclic Bedouin goats (Capra hircus): Nychthemeral and seasonal variations of some haematochemical parameters in relation with body and ambient temperatures.

    PubMed

    Malek, Mouna; Amirat, Zaina; Khammar, Farida; Khaldoun, Mounira

    2016-08-01

    Several studies have examined changes in some haematochemical parameters as a function of the different physiological status (cyclic, pregnant and lactating) of goats, but no relevant literature has exhaustively investigated these variations from anestrous to estrous stages in cyclic goats. In this paper, we report nychthemeral and seasonal variations in ambient and body temperatures, and in some haematochemical parameters (glycemia, cholesterolemia, triglyceridemia, creatininemia and uremia) measured during summer, winter and spring, in seven (7) experimental cyclic female Bedouin goats (Capra hircus) living in the Béni-Abbès region (Algerian Sahara desert). Cosinor rhythmometry procedure was used to determine the rhythmic parameters of ambient temperature and haematochemical parameters. To determine the effect of time of day on the rhythmicity of the studied parameters, as well as their seasonality, repeated measure analysis of variance (ANOVA) was applied. The results showed that in spite of the nychthemeral profile presented by the ambient temperature for each season, the body temperature remained in a narrow range, thus indicating a successful thermoregulation. The rhythmometry analysis showed a circadian rhythmicity of ambient temperature and haematochemical parameters with diurnal acrophases. A statistically significant effect of the time of day was shown on all studied haematochemical parameters, except on creatininemia. It was also found that only uremia, cholesterolemia and triglyceridemia followed the seasonal sexual activity of the studied ruminant. This study demonstrated the good physiological adaptation developed by this breed in response to the harsh climatic conditions of its natural environment. PMID:27503720

  12. Spatial Variations in CO2 Mixing Ratios Over a Heterogenous Landscape - Linking Airborne Measurements With Remote Sensing Derived Biophysical Parameters

    NASA Astrophysics Data System (ADS)

    Choi, Y.; Vadrevu, K. P.; Vay, S. A.; Woo, J.

    2006-12-01

    North American terrestrial ecosystems are major sources and sinks of carbon. Precise measurement of atmospheric CO2 concentrations plays an important role in the development and testing of carbon cycle models quantifying the influence of terrestrial CO2 exchange on the North American carbon budget. During the summer 2004 Intercontinental Chemical Transport Experiment North America (INTEX-NA) campaign, regional scale in-situ measurements of atmospheric CO2 were made from the NASA DC-8 affording the opportunity to explore how land surface heterogeneity relates to the airborne observations utilizing remote-sensing data products and GIS-based methods. These 1 Hz data reveal the seasonal biospheric uptake of CO2 over portions of the U.S. continent, especially east of 90°W below 2 km, compared to higher mixing ratios over water as well as within the upper troposphere where well-mixed, aged air masses were sampled. In this study, we use several remote sensing derived biophysical parameters from the LANDSAT, NOAA AVHRR, and MODIS sensors to specify spatiotemporal patterns of land use cover and vegetation characteristics for linking the airborne measurements of CO2 data with terrestrial sources of carbon. Also, CO2 flux footprint outputs from a 3-D Lagrangian atmospheric model have been integrated with satellite remote sensing data to infer CO2 variations across heterogeneous landscapes. In examining the landscape mosaic utilizing these available tools, preliminary results suggest that the lowest CO2 mixing ratios observed during INTEX-NA were over agricultural fields in Illinois dominated by corn then secondarily soybean crops. Low CO2 concentrations are attributable to sampling during the peak growing season over such C4 plants as corn having a higher photosynthetic rate via the C4-dicarboxylic acid pathway of carbon fixation compared to C3 plants such as soybeans. In addition to LANDSAT derived land cover data, results from comparisons of the airborne CO2 observations

  13. Mechanism and kinetics of organic matter degradation based on particle structure variation during pig manure aerobic composting.

    PubMed

    Ge, Jinyi; Huang, Guangqun; Huang, Jing; Zeng, Jianfei; Han, Lujia

    2015-07-15

    Characterization of the dynamic structure of composting particles may facilitate our understanding of the mechanisms of organic matter degradation during pig manure-wheat straw aerobic composting. In this study, changes in the size, shape, pores, chemical compositions, and crystal structures of pig manure particles during composting were investigated. The results showed that the median diameter (D50) decreased exponentially, while the particle aspect ratio and sphericity were unchanged, suggesting that particles were degraded uniformly along different radial directions. Pores had a mean diameter of 15-30 μm and were elliptical. The particle porosity increased linearly mainly because of hemicellulose degradation. Furthermore, the influence of particle structure variation on the first order rate constant (k) of organic matter degradation was corrected, which may facilitate the optimization of operation conditions. The k value was proportional to the reciprocal of D50 according to the specific surface area of particles, and it decreased with increased porosity due to the stabilized chemical compositions and crystal structures of particles. However, the applicability of these data to other composting materials should be verified. PMID:25781372

  14. Kinetics of Hydrogen Radical Reactions with Toluene Including Chemical Activation Theory Employing System-Specific Quantum RRK Theory Calibrated by Variational Transition State Theory.

    PubMed

    Bao, Junwei Lucas; Zheng, Jingjing; Truhlar, Donald G

    2016-03-01

    Pressure-dependent reactions are ubiquitous in combustion and atmospheric chemistry. We employ a new calibration procedure for quantum Rice-Ramsperger-Kassel (QRRK) unimolecular rate theory within a chemical activation mechanism to calculate the pressure-falloff effect of a radical association with an aromatic ring. The new theoretical framework is applied to the reaction of H with toluene, which is a prototypical reaction in the combustion chemistry of aromatic hydrocarbons present in most fuels. Both the hydrogen abstraction reactions and the hydrogen addition reactions are calculated. Our system-specific (SS) QRRK approach is adjusted with SS parameters to agree with multistructural canonical variational transition state theory with multidimensional tunneling (MS-CVT/SCT) at the high-pressure limit. The new method avoids the need for the usual empirical estimations of the QRRK parameters, and it eliminates the need for variational transition state theory calculations as a function of energy, although in this first application we do validate the falloff curves by comparing SS-QRRK results without tunneling to multistructural microcanonical variational transition state theory (MS-μVT) rate constants without tunneling. At low temperatures, the two approaches agree well with each other, but at high temperatures, SS-QRRK tends to overestimate falloff slightly. We also show that the variational effect is important in computing the energy-resolved rate constants. Multiple-structure anharmonicity, torsional-potential anharmonicity, and high-frequency-mode vibrational anharmonicity are all included in the rate computations, and torsional anharmonicity effects on the density of states are investigated. Branching fractions, which are both temperature- and pressure-dependent (and for which only limited data is available from experiment), are predicted as a function of pressure. PMID:26841076

  15. Geostatistical Characteristic of Space -Time Variation in Underground Water Selected Quality Parameters in Klodzko Water Intake Area (SW Part of Poland)

    NASA Astrophysics Data System (ADS)

    Namysłowska-Wilczyńska, Barbara

    2016-04-01

    This paper presents selected results of research connected with the development of a (3D) geostatistical hydrogeochemical model of the Klodzko Drainage Basin, dedicated to the spatial and time variation in the selected quality parameters of underground water in the Klodzko water intake area (SW part of Poland). The research covers the period 2011÷2012. Spatial analyses of the variation in various quality parameters, i.e, contents of: ammonium ion [gNH4+/m3], NO3- (nitrate ion) [gNO3/m3], PO4-3 (phosphate ion) [gPO4-3/m3], total organic carbon C (TOC) [gC/m3], pH redox potential and temperature C [degrees], were carried out on the basis of the chemical determinations of the quality parameters of underground water samples taken from the wells in the water intake area. Spatial and time variation in the quality parameters was analyzed on the basis of archival data (period 1977÷1999) for 22 (pump and siphon) wells with a depth ranging from 9.5 to 38.0 m b.g.l., later data obtained (November 2011) from tests of water taken from 14 existing wells. The wells were built in the years 1954÷1998. The water abstraction depth (difference between the terrain elevation and the dynamic water table level) is ranged from 276÷286 m a.s.l., with an average of 282.05 m a.s.l. Dynamic water table level is contained between 6.22 m÷16.44 m b.g.l., with a mean value of 9.64 m b.g.l. The latest data (January 2012) acquired from 3 new piezometers, with a depth of 9÷10m, which were made in other locations in the relevant area. Thematic databases, containing original data on coordinates X, Y (latitude, longitude) and Z (terrain elevation and time - years) and on regionalized variables, i.e. the underground water quality parameters in the Klodzko water intake area determined for different analytical configurations (22 wells, 14 wells, 14 wells + 3 piezometers), were created. Both archival data (acquired in the years 1977÷1999) and the latest data (collected in 2011÷2012) were analyzed

  16. Assessment of the aerobic preparation and bottom ash addition as pretreatment steps before landfilling: impact on methanogenesis kinetics and leachate parameters.

    PubMed

    Mansour, Alicia A; Motte, Antoine; Pallier, Virginie; Feuillade-Cathalifaud, Geneviève; Ponthieux, Arnaud

    2012-10-01

    This work focuses on assessing the impact of two types of waste pretreatment: addition of bottom ashes and aerobic pretreatment on both the onset and kinetics of methanogenesis and the evolution of different parameters in the leachate. It also studies the correlation between methane production and the different parameters measured in the leachate produced. A total of six 68-L pilots were thus used with fresh municipal solid waste (MSW) shredded to a 40-mm size. After 14 months of landfilling, the control has produced less than 10 NLkg(-1)DM, which corresponds to around 7% of its biochemical methane potential (BMP). Nevertheless, on one hand for aerobically pretreated waste, the lag phase before the onset of methanogenesis is significantly reduced to 0.9 month compared to more than 1 year for the control. In addition to that, on average 110 NLkg(-1)DM (90% of the BMP) is produced within around 6.5 months. On the other hand, the waste with added bottom ash shows a slight improvement of the lag phase over the control for one of the duplicate: 6.1 months of lag phase. At this stage, on average of 26 NLkg(-1)DM waste are detected (22% of the BMP) no final conclusion concerning the impact of bottom ashes could be made. The data obtained for the leachate parameters agrees with the observations on methane production. Statistical correlation study shows that the two components of the corrected PCA interpret 76% of the variability of the data: SUVA (specific UV absorbance at 254 nm) and HPI(*) (% of hydrophilic compounds) are identified as interesting parameters for following up the biodegradation in landfill conditions. PMID:22640801

  17. Isotopic discrimination and kinetic parameters of RubisCO from the marine bloom-forming diatom, Skeletonema costatum.

    PubMed

    Boller, A J; Thomas, P J; Cavanaugh, C M; Scott, K M

    2015-01-01

    The cosmopolitan, bloom-forming diatom, Skeletonema costatum, is a prominent primary producer in coastal oceans, fixing CO2 with ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) that is phylogenetically distinct from terrestrial plant RubisCO. RubisCOs are subdivided into groups based on sequence similarity of their large subunits (IA-ID, II, and III). ID is present in several major oceanic primary producers, including diatoms such as S. costatum, coccolithophores, and some dinoflagellates, and differs substantially in amino acid sequence from the well-studied IB enzymes present in most cyanobacteria and in green algae and plants. Despite this sequence divergence, and differences in isotopic discrimination apparent in other RubisCO enzymes, stable carbon isotope compositions of diatoms and other marine phytoplankton are generally interpreted assuming enzymatic isotopic discrimination similar to spinach RubisCO (IB). To interpret phytoplankton δ(13) C values, S. costatum RubisCO was characterized via sequence analysis, and measurement of its KCO2 and Vmax , and degree of isotopic discrimination. The sequence of this enzyme placed it among other diatom ID RubisCOs. Michaelis-Menten parameters were similar to other ID enzymes (KCO2 = 48.9 ± 2.8 μm; Vmax = 165.1 ± 6.3 nmol min(-1 ) mg(-1) ). However, isotopic discrimination (ε = [(12) k/(13) k - 1] × 1000) was low (18.5‰; 17.0-19.9, 95% CI) when compared to IA and IB RubisCOs (22-29‰), though not as low as ID from coccolithophore, Emiliania huxleyi (11.1‰). Variability in ε-values among RubisCOs from primary producers is likely reflected in δ(13) C values of oceanic biomass. Currently, δ(13) C variability is ascribed to physical or chemical factors (e.g. illumination, nutrient availability) and physiological responses to these factors (e.g. carbon-concentrating mechanisms). Estimating the importance of these factors from δ(13) C measurements requires an accurate ε-value, and a mass

  18. Evolution of a mini-scale biphasic dissolution model: Impact of model parameters on partitioning of dissolved API and modelling of in vivo-relevant kinetics.

    PubMed

    Locher, Kathrin; Borghardt, Jens M; Frank, Kerstin J; Kloft, Charlotte; Wagner, Karl G

    2016-08-01

    Biphasic dissolution models are proposed to have good predictive power for the in vivo absorption. The aim of this study was to improve our previously introduced mini-scale dissolution model to mimic in vivo situations more realistically and to increase the robustness of the experimental model. Six dissolved APIs (BCS II) were tested applying the improved mini-scale biphasic dissolution model (miBIdi-pH-II). The influence of experimental model parameters including various excipients, API concentrations, dual paddle and its rotation speed was investigated. The kinetics in the biphasic model was described applying a one- and four-compartment pharmacokinetic (PK) model. The improved biphasic dissolution model was robust related to differing APIs and excipient concentrations. The dual paddle guaranteed homogenous mixing in both phases; the optimal rotation speed was 25 and 75rpm for the aqueous and the octanol phase, respectively. A one-compartment PK model adequately characterised the data of fully dissolved APIs. A four-compartment PK model best quantified dissolution, precipitation, and partitioning also of undissolved amounts due to realistic pH profiles. The improved dissolution model is a powerful tool for investigating the interplay between dissolution, precipitation and partitioning of various poorly soluble APIs (BCS II). In vivo-relevant PK parameters could be estimated applying respective PK models. PMID:27297570

  19. A review of uncertainties in atmospheric modeling of mercury chemistry I. Uncertainties in existing kinetic parameters - Fundamental limitations and the importance of heterogeneous chemistry

    NASA Astrophysics Data System (ADS)

    Subir, Mahamud; Ariya, Parisa A.; Dastoor, Ashu P.

    2011-10-01

    Mercury and its related compounds are widely recognized as global pollutants. The accurate atmospheric modeling of its transport and fate has been the subject of much research throughout the last decade. Atmospheric gas, aqueous and heterogeneous chemistry are expected to occur for Hg-containing species and accurate implementation of their chemical parameters is essential for realistic modeling of mercury cycling. Although significant progress has been made, the current state of knowledge of mercury chemistry exhibits numerous uncertainties. The objective of this two-part review is to explore the sources of uncertainty from the viewpoint of mercury chemistry. In this first part, we assess the discrepancy that exists in the currently available mercury kinetic parameters for the gas and aqueous phases. Theoretical and experimental approaches of rate constant determination exhibit various levels of limitation and accuracy. We present an overview of the available techniques and the assumptions and shortcomings associated with these methods in order to assist the atmospheric modellers. We review specific mercury oxidation and reduction reactions that have been investigated and are commonly implemented in mercury models with respect to the uncertainties associated with them. We reveal that for most of these mercury reactions our current state of knowledge reflects a lack of proper understanding of their mechanisms. Atmospheric heterogeneity is a topic of great importance and we elaborate upon it in part II of this review.

  20. Fundamental electrode kinetics

    NASA Technical Reports Server (NTRS)

    Elder, J. P.

    1968-01-01

    Report presents the fundamentals of electrode kinetics and the methods used in evaluating the characteristic parameters of rapid-charge transfer processes at electrode-electrolyte interfaces. The concept of electrode kinetics is outlined, followed by the principles underlying the experimental techniques for the investigation of electrode kinetics.

  1. Kinetic parameters, collision rates, energy exchanges and transport coefficients of non-thermal electrons in premixed flames at sub-breakdown electric field strengths

    NASA Astrophysics Data System (ADS)

    Bisetti, Fabrizio; El Morsli, Mbark

    2014-01-01

    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.

  2. Some wind and instability parameters associated with strong and violent tornadoes: 2. Variations in the combinations of wind and instability parameters

    NASA Astrophysics Data System (ADS)

    Johns, Robert H.; Davies, Jonathan M.; Leftwich, Preston W.

    Meteorologists have long known that both potential buoyant energy and the strength and vertical profile of the tropospheric wind fields are important in the process of tornado development [e.g., Miller, 1972]. Further, operational experience suggests that the combinations of wind parameters and instability parameters vary considerably from one tornado situation to another. Numerical models suggest that the type of storm that develops in a given situation (e.g., an isolated supercell) is related to both the vertical wind profile and the potential buoyant energy of the air in the updraft entrainment layer [Weisman and Klemp, 1982, 1986]. Observational studies by Rasmussen and Wilhelmson [1983] and Leftwich and Wu [1988] have examined the wind shear/potential buoyant energy relationship in association with tornado development. These studies involved limited data sets and were concerned with the wind shear in a relatively deep layer of the troposphere (0-4-km above ground level (AGL)). Recently, interest has focused on the nature of the wind fields in shallower layers of the lower troposphere, layers that more nearly correspond to the updraft entrainment region [Davies, 1989; Davies-Jones et al., 1990]. Utilizing a large comprehensive data set, Johns et al [1990] (hereafter referred to as JDL) examined the relationship between 0-2-km AGL "positive" wind shear (PWS) and convective available potential energy (CAPE) [Moncrieff and Green, 1972] in association with strong and violent tornado development. In this paper (part 2) the authors review the initial work of JDL and examine additional wind and potential buoyant energy parameter relationships associated with the data set compiled by JDL.

  3. Period variations in pulsating X-ray sources. I - Accretion flow parameters and neutron star structure from timing observations

    NASA Technical Reports Server (NTRS)

    Lamb, F. K.; Shaham, J.; Pines, D.

    1978-01-01

    Torque fluctuations which can lead to variations in the periods of pulsating X-ray sources are examined. A description of torque variations in terms of noise processes is developed, and the resulting noise models are applied to observations of several pulsating X-ray sources. It is shown that fluctuations in accretion torque could account for the observed period variations and spindown episodes in Her X-1 and Cen X-3. The values of the torque noise strengths inferred from either a nonresonant response or, in the case of Her X-1, a Tkachenko-mode interpretation of the data are found to be consistent with those expected from processes at the magnetospheric boundary of an accreting neutron star. Ways to distinguish among the various interpretations of the period variations are considered. It is noted that fluctuating mass-flow rates may be responsible for other phenomena observed in compact X-ray sources, such as wobble with zero initial amplitude and binary period variations in close binary systems experiencing mass transfer.

  4. Spatiotemporal variation of nitrate uptake kinetics within the maize (Zea mays L.) root system is associated with greater nitrate uptake and interactions with architectural phenes.

    PubMed

    York, Larry M; Silberbush, Moshe; Lynch, Jonathan P

    2016-06-01

    Increasing maize nitrogen acquisition efficiency is a major goal for the 21st century. Nitrate uptake kinetics (NUK) are defined by I max and K m, which denote the maximum uptake rate and the affinity of transporters, respectively. Because NUK have been studied predominantly at the molecular and whole-root system levels, little is known about the functional importance of NUK variation within root systems. A novel method was created to measure NUK of root segments that demonstrated variation in NUK among root classes (seminal, lateral, crown, and brace). I max varied among root class, plant age, and nitrate deprivation combinations, but was most affected by plant age, which increased I max, and nitrate deprivation time, which decreased I max K m was greatest for crown roots. The functional-structural simulation SimRoot was used for sensitivity analysis of plant growth to root segment I max and K m, as well as to test interactions of I max with root system architectural phenes. Simulated plant growth was more sensitive to I max than K m, and reached an asymptote near the maximum I max observed in the empirical studies. Increasing the I max of lateral roots had the largest effect on shoot growth. Additive effects of I max and architectural phenes on nitrate uptake were observed. Empirically, only lateral root tips aged 20 d operated at the maximum I max, and simulations demonstrated that increasing all seminal and lateral classes to this maximum rate could increase plant growth by as much as 26%. Therefore, optimizing I max for all maize root classes merits attention as a promising breeding goal. PMID:27037741

  5. HCCI in a CFR engine: experiments and detailed kinetic modeling

    SciTech Connect

    Flowers, D; Aceves, S; Smith, R; Torres, J; Girard, J; Dibble, R

    1999-11-05

    Single cylinder engine experiments and chemical kinetic modeling have been performed to study the effect of variations in fuel, equivalence ratio, and intake charge temperature on the start of combustion and the heat release rate. Neat propane and a fuel blend of 15% dimethyl-ether in methane have been studied. The results demonstrate the role of these parameters on the start of combustion, efficiency, imep, and emissions. Single zone kinetic modeling results show the trends consistent with the experimental results.

  6. Variation in ruminal in situ degradation of crude protein and starch from maize grains compared to in vitro gas production kinetics and physical and chemical characteristics.

    PubMed

    Seifried, Natascha; Steingaß, Herbert; Schipprack, Wolfgang; Rodehutscord, Markus

    2016-10-01

    The objectives of this study were (1) to evaluate in situ ruminal dry matter (DM), crude protein (CP) and starch degradation characteristics and in vitro gas production (GP) kinetics using a set of 20 different maize grain genotypes and (2) to predict the effective degradation (ED) of CP and starch from chemical and physical characteristics alone or in combination with in vitro GP measurements. Maize grains were characterised by different chemical and physical characteristics. Ruminal in situ degradation was measured in three lactating Jersey cows. Ground grains (sieve size: 2 mm) were incubated in bags for 1, 2, 4, 8, 16, 24, 48 and 72 h. Bag residues were analysed for CP and starch content. Degradation kinetics was determined and the ED of DM, CP and starch calculated using a ruminal passage rate of 5%/h and 8%/h. The GP of the grains (sieve size: 1 mm) was recorded after 2, 4, 6, 8, 12, 24, 48 and 72 h incubation in buffered rumen fluid and fitted to an exponential equation to determine GP kinetics. Correlations and stepwise multiple linear regressions were evaluated for the prediction of ED calculated for a passage rate of 5%/h (ED5) for CP (EDCP5) and starch (EDST5). The in situ parameters and ED5 varied widely between genotypes with average values (±SD) of 64% ± 4.2, 62% ± 4.1 and 65% ± 5.2 for ED5 of DM, EDCP5 and EDST5 and were on average 10 percentage points lower for a passage rate of 8%/h. Degradation rates varied between 4.8%/h and 7.4%/h, 4.1%/h and 6.5%/h and 5.3%/h and 8.9%/h for DM, CP and starch, respectively. These rates were in the same range as GP rates (6.0-8.3%/h). The EDCP5 and EDST5 were related to CP concentration and could be evaluated in detail using CP fractions and specific amino acids. In vitro GP measurements and GP rates correlated well with EDCP5 and EDST5 and predicted EDCP5 and EDST5 in combination with the chemical characteristics of the samples. Equations can be used to obtain quick and cost effective information

  7. A new conception of space weather prediction based on the UT variations of geoeffective parameters and its validation for 35 years of spaced measurements

    NASA Astrophysics Data System (ADS)

    Kuznetsova, T. V.; Laptukhov, A. I.

    As we become a space culture, we are more and more in need of a predictive understanding of the key processes that constitute the interaction of the solar wind plasma and the IMF with the terrestrial magnetic field. The paper presents results of our analysis of geoeffective parameters of the solar wind calculated from measurements of the solar wind and interplanetary magnetic field (IMF) for the period from 1964-1999 of space measurements at 1 a.u. at ecliptic plane and Kp, Dst indexes (planetary geomagnetic activity). We attract for calculation of geoeffective parameters a reconnection model that describes a reconnection between terrestrial magnetic field and an IMF of arbitrary orientation taking into account annual and daily rotations of the Earth's dipole (Kuznetsova and Laptukhov, 2001). As result we introduce two new geoeffective invariant parameters (independent from a choice of a coordinate system) that have clear physical sense of components of electric field of the solar wind along special directions of the geomagnetic moment (M): vector of electric field of the solar wind E are presented by its projections along and across the M vector (Em and Emv). For calculations of the electric field we used measured components of the IMF and solar wind velocity V. To project vector E along the directions we calculated orientation of geomagnetic moment at each moment of the Universal Time during its orbital motion (in GSE coordinate system). In terms of our approach mutual orientation of vectors of E and M is important. We obtained two functional dependencies: Kp=F1(Emv), Kp=F2(Em) on the basis of measurements for 35 years. Remarkable feature of derived functions Kp=F1(Emv), Kp=F2(Em) is that standard error is nearly the same both for high and low values of Kp (including extreme values). Results demonstrate that Emv electric field is one the main contributor to the Kp variations. Results of our detailed analysis showed that Emv can explain 94.5 % variations in Kp, Em

  8. Statistical variations of source parameters in inter- and intraplate earthquakes in Chile and their correlations with the slab properties.

    NASA Astrophysics Data System (ADS)

    Derode, B.

    2015-12-01

    Understanding the rupture processes of intermediate-depth earthquakes in active subduction zones and their dependence to inherited geophysical parameters, such as the maturity and orientation of pre-existing faults, is still of prime interest. Unfortunately, quantitative values describing the nucleation and propagation processes at depths are rare, and the earthquake source parameters determined from global databases or far-field measurements are often very heterogeneous, especially for the smallest and deepest earthquakes. In order to leveling this problem and discriminate specific characteristics of the intermediate-depth earthquakes in Chile (IDEQ-Chile), we conducted high precision measurements using local and regional waveforms data obtained from broadband and strong-motions stations of IPOC network in northern Chile. A strict and rigorous methodology was used to reduce the scattering of the source parameter estimation usually observed. With this high-quality database, we examined the source characteristics of a few hundreds of intra-slab intermediate depth-earthquakes, with depth varying from 40 km to 300 km. For the effective comparison of the source parameters, we studied with the same approach a hundred of interplate earthquakes located along the same latitude-dependent zone of the subducted slab. Based on static and cinematic considerations, we compared these source parameters with macroscopic geophysical parameters such as the stress regime, the coupling degree or the style of faulting, in order to show the possible correlations between them. Interestingly, we observed three major depth-dependent zones corresponding to three different sets of static and dynamic source parameters. We show that there are some evident differences between these distinct Chilean zones, although the apparent quasi-constant velocity and age of the subducted Nazca plate along Chile. We discuss how some of the various proposed sources mechanisms, explaining the earthquakes

  9. Method for On-line Estimation of Electrical Motor Parameter Variation and Current Sensor Offset for SPM Motor

    NASA Astrophysics Data System (ADS)

    Uenaka, Yutaro; Sazawa, Masaki; Ohishi, Kiyoshi; Kenji, Takahashi

    The servo system of a permanent magnet (PM) motor should always maintain fine torque and fine speed responses. Accurate motor parameter identification is necessary for the PM motor servo system because the current control system is designed by considering the electric parameters of the PM motor. However, the motor parameters vary with the age of the motor and temperature. Moreover, current sensors have offset values. When the current sensor has offset values, the PM motor servo system produces torque ripple. In order to overcome these problems, this paper proposes a new real-time estimation method for both current sensor offsets and electrical parameters (resistance Ra, inductance La, and magnetic flux φfa) of the surface permanent magnet (SPM) motor. The proposed method involves the use of a real-time algorithm and a current simulator, which is operated using a DSP software system. In order to accurately estimate the motor parametera, the proposed method is using estimate currents, DC terms of sensor currents, and nominal motor parameter value. The experimental results of this study confirm that the proposed method satisfactorily estimates the current sensor offset of the U phase and V phase, as well as the electrical motor parametersRa, La, and φfa accurately.

  10. Kinetic model framework for aerosol and cloud surface chemistry and gas-particle interactions - Part 1: General equations, parameters, and terminology

    NASA Astrophysics Data System (ADS)

    Pöschl, U.; Rudich, Y.; Ammann, M.

    2007-12-01

    Aerosols and clouds play central roles in atmospheric chemistry and physics, climate, air pollution, and public health. The mechanistic understanding and predictability of aerosol and cloud properties, interactions, transformations, and effects are, however, still very limited. This is due not only to the limited availability of measurement data, but also to the limited applicability and compatibility of model formalisms used for the analysis, interpretation, and description of heterogeneous and multiphase processes. To support the investigation and elucidation of atmospheric aerosol and cloud surface chemistry and gas-particle interactions, we present a comprehensive kinetic model framework with consistent and unambiguous terminology and universally applicable rate equations and parameters. It enables a detailed description of mass transport and chemical reactions at the gas-particle interface, and it allows linking aerosol and cloud surface processes with gas phase and particle bulk processes in systems with multiple chemical components and competing physicochemical processes. The key elements and essential aspects of the presented framework are: a simple and descriptive double-layer surface model (sorption layer and quasi-static layer); straightforward flux-based mass balance and rate equations; clear separation of mass transport and chemical reactions; well-defined and consistent rate parameters (uptake and accommodation coefficients, reaction and transport rate coefficients); clear distinction between gas phase, gas-surface, and surface-bulk transport (gas phase diffusion, surface and bulk accommodation); clear distinction between gas-surface, surface layer, and surface-bulk reactions (Langmuir-Hinshelwood and Eley-Rideal mechanisms); mechanistic description of concentration and time dependences (transient and steady-state conditions); flexible addition of unlimited numbers of chemical species and physicochemical processes; optional aggregation or resolution

  11. Combining wood anatomy and stable isotope variations in a 600-year multi-parameter climate reconstruction from Corsican black pine

    NASA Astrophysics Data System (ADS)

    Szymczak, Sonja; Hetzer, Timo; Bräuning, Achim; Joachimski, Michael M.; Leuschner, Hanns-Hubert; Kuhlemann, Joachim

    2014-10-01

    We present a new multi-parameter dataset from Corsican black pine growing on the island of Corsica in the Western Mediterranean basin covering the period AD 1410-2008. Wood parameters measured include tree-ring width, latewood width, earlywood width, cell lumen area, cell width, cell wall thickness, modelled wood density, as well as stable carbon and oxygen isotopes. We evaluated the relationships between different parameters and determined the value of the dataset for climate reconstructions. Correlation analyses revealed that carbon isotope ratios are influenced by cell parameters determining cell size, whereas oxygen isotope ratios are influenced by cell parameters determining the amount of transportable water in the xylem. A summer (June to August) precipitation reconstruction dating back to AD 1185 was established based on tree-ring width. No long-term trends or pronounced periods with extreme high/low precipitation are recorded in our reconstruction, indicating relatively stable moisture conditions over the entire time period. By comparing the precipitation reconstruction with a summer temperature reconstruction derived from the carbon isotope chronologies, we identified summers with extreme climate conditions, i.e. warm-dry, warm-wet, cold-dry and cold-wet. Extreme climate conditions during summer months were found to influence cell parameter characteristics. Cold-wet summers promote the production of broad latewood composed of wide and thin-walled tracheids, while warm-wet summers promote the production of latewood with small thick-walled cells. The presented dataset emphasizes the potential of multi-parameter wood analysis from one tree species over long time scales.

  12. Effect of genetic and physiological manipulations onthe kinetic and binding parameters of the adenine nucleotide translocator in Saccharomyces cervisiae and Candida utilis.

    PubMed

    Lauquin, G; Lunardi, J; Vignais, P V

    1976-01-01

    1. Ghe kinetic and binding parameters of adenine-nucleotide transport have been studied in mitochondria isolated from yeast cells in which the mitochondrial protein-synthetizing system had been inhibited by growth in the presence of erythromycin. These parameters have also been studied in promitochondria isolated from yeast grown in anaerobiosis aesence of ethidium bromide results in a loss of cytochromes b, alpha and alpha 3, but it does not affect the rate constant of ADP transport in isolated mitochondria, nor the number of binding sites for atractyloside, bongkrekic acid and ADP. 3. Promitochondria from S. cerevisiae grown in anaerobiosis, mitochondria from a qo mutant (qo mitochondria) and mitochondria from S. cerevisiae grown in the presence of erythromycin (ERY-mitochondria) are able to transport ADP by the same exchange-diffusion mechanism, sensitive to carboxy-atractyloside, and with the same rate constant as the wild type mitochondria. Promitochondria, qo mitochondria and ERY-mitochondria bind atractyloside, bongkrekic acid and ADP with the same high affinity as the wild type mitochondria. They only differ from the wild type mitochondria by a lower number of binding sites for ADP and for specific inhibitors of ADP transport. 4. Mitochondria isolated from the nuclear mutant p9 of S. cerevisae, called also op1, are characterized by a much lower affinity for bongkrekic acid than mitochondria from the wild type (20 times less). 5. Manipulation of the fatty acid composition of the mitochondrial membranes in the desaturase auxotroph mutant KD115 does not modify the number of sites, no their affinity of bongkrekic acid. 6. The above results are interpreted to mean that the structure and function of the mitochondrial adN translocator are not affected by any change in the mitochondrial protein synthetizing system. PMID:795470

  13. Effect of L-lactic acid, short-chain fatty acids, and pH in cecal infusate on morphometric and cell kinetic parameters of rat cecum.

    PubMed

    Ichikawa, H; Sakata, T

    1997-08-01

    We studied the influences of cecal infusion of NaCl, short-chain fatty acids (SCFA), and L-lactic acid at pH 5.0 or 7.0 for seven days on morphometric and cell kinetic parameters of the rat cecum. SCFA increased relative weight of the mucosa and submucosa, crypt size, and mitotic index in the cecum. L-Lactic acid stimulated mitosis only at pH 5.0. Crypt size correlated positively to epithelial proliferative activity only when NaCl or L-lactic acid was infused. SCFA should have changed the balance between production and loss of the cecal epithelial cells. The infusate pH by itself had no effect, but modified the effects of SCFA and L-lactic acid in different ways. Crypt size correlated positively to the logarithm of daily proton load of infusates. The above results indicate that epithelial cell proliferation in the cecum is influenced by both SCFA and L-lactic acid, although differently, and by proton load. PMID:9286223

  14. Kinetic Parameters and Cytotoxic Activity of Recombinant Methionine γ-Lyase from Clostridium tetani, Clostridium sporogenes, Porphyromonas gingivalis and Citrobacter freundii.

    PubMed

    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. PMID:24303205

  15. Coalescent-based method for learning parameters of admixture events from large-scale genetic variation data.

    PubMed

    Tsai, Ming-Chi; Blelloch, Guy; Ravi, R; Schwartz, Russell

    2013-01-01

    Detecting and quantifying the timing and the genetic contributions of parental populations to a hybrid population is an important but challenging problem in reconstructing evolutionary histories from genetic variation data. With the advent of high throughput genotyping technologies, new methods suitable for large-scale data are especially needed. Furthermore, existing methods typically assume the assignment of individuals into subpopulations is known, when that itself is a difficult problem often unresolved for real data. Here, we propose a novel method that combines prior work for inferring non reticulate population structures with an MCMC scheme for sampling over admixture scenarios to both identify population assignments and learn divergence times and admixture proportions for those populations using genome-scale admixed genetic variation data. We validated our method using coalescent simulations and a collection of real bovine and human variation data. On simulated sequences, our methods show better accuracy and faster run time than leading competitive methods in estimating admixture fractions and divergence times. Analysis on the real data further shows our methods to be effective at matching our best current knowledge about the relevant populations. PMID:23959633

  16. Study on the effect of hydrogen addition on the variation of plasma parameters of argon-oxygen magnetron glow discharge for synthesis of TiO2 films

    NASA Astrophysics Data System (ADS)

    Saikia, Partha; Saikia, Bipul Kumar; Bhuyan, Heman

    2016-04-01

    We report the effect of hydrogen addition on plasma parameters of argon-oxygen magnetron glow discharge plasma in the synthesis of H-doped TiO2 films. The parameters of the hydrogen-added Ar/O2 plasma influence the properties and the structural phases of the deposited TiO2 film. Therefore, the variation of plasma parameters such as electron temperature (Te), electron density (ne), ion density (ni), degree of ionization of Ar and degree of dissociation of H2 as a function of hydrogen content in the discharge is studied. Langmuir probe and Optical emission spectroscopy are used to characterize the plasma. On the basis of the different reactions in the gas phase of the magnetron discharge, the variation of plasma parameters and sputtering rate are explained. It is observed that the electron and heavy ion density decline with gradual addition of hydrogen in the discharge. Hydrogen addition significantly changes the degree of ionization of Ar which influences the structural phases of the TiO2 film.

  17. Variation of the Earth tide-seismicity compliance parameter during the recent seismic activity of Fthiotida, Greece

    NASA Astrophysics Data System (ADS)

    Contadakis, Michael; Aarabelos, Dimitrios; Vergos, Georgios; Spatalas, Spyridon

    2014-05-01

    Applying the Hi(stogram)Cum(ulation) method, which was introduced recently by Cadicheanu, van Ruymbecke and Zhu (2007), we analyze the series of the earthquakes occurred in the last 50 years in seismic active areas of Greece, i.e. the areas (a) of the Mygdonian Basin(Contadakis et al. 2007), (b) of the Ionian Islands (Contadakis et al. 2012 ) and (c) of the Hellenic Arc (Vergos et al. 2012 ) . The result of the analysis for all the areas indicate that the monthly variation of the frequencies of earthquake occurrence is in accordance with the period of the tidal lunar monthly and semi-monthly (Mm and Mf) variations and the same happens with the corresponding daily variations of the frequencies of earthquake occurrence with the diurnal luni-solar (K1) and semidiurnal lunar (M2) tidal variations. In addition the confidence level for the identifiation of such period accordance between earthquakes occurrence frequency and tidal periods varies with seismic activity, i.e. the higher confidence level corresponds to periods with stronger seismic activity. These results are in favor of a tidal triggering process on earthquakes when the stress in the focal area is near the critical level. Based on these results, we consider the confidence level of earthquake occurrence - tidal period accordance, p, as an index of tectonic stress criticality for earthquake occurrence and we check on posterior if the variation of the confidence level index, p, indicate the fault matureness in the case of the recent seismic activity at Fthiotida, Greece. In this paper we present the results of this test. References Cadicheanu, N., van Ruymbeke, M andZhu P.,2007:Tidal triggering evidence of intermediate depth earthquakes in Vrancea zone(Romania), NHESS 7,733-740. Contadakis, M. E., Arabelos, D. N., Spatalas, S., 2009, Evidence for tidal triggering on the shallow earthquakes of the seismic area of Mygdonia basin, North Greece, in Terrestrial and Stellar Environment, eds.D. Arabelos, M

  18. Effects of particle size and coating on toxicologic parameters, fecal elimination kinetics and tissue distribution of acutely ingested silver nanoparticles in a mouse model.

    PubMed

    Bergin, Ingrid L; Wilding, Laura A; Morishita, Masako; Walacavage, Kim; Ault, Andrew P; Axson, Jessica L; Stark, Diana I; Hashway, Sara A; Capracotta, Sonja S; Leroueil, Pascale R; Maynard, Andrew D; Philbert, Martin A

    2016-01-01

    Consumer exposure to silver nanoparticles (AgNP) via ingestion can occur due to incorporation of AgNP into products such as food containers and dietary supplements. AgNP variations in size and coating may affect toxicity, elimination kinetics or tissue distribution. Here, we directly compared acute administration of AgNP of two differing coatings and sizes to mice, using doses of 0.1, 1 and 10 mg/kg body weight/day administered by oral gavage for 3 days. The maximal dose is equivalent to 2000× the EPA oral reference dose. Silver acetate at the same doses was used as ionic silver control. We found no toxicity and no significant tissue accumulation. Additionally, no toxicity was seen when AgNP were dosed concurrently with a broad-spectrum antibiotic. Between 70.5% and 98.6% of the administered silver dose was recovered in feces and particle size and coating differences did not significantly influence fecal silver. Peak fecal silver was detected between 6- and 9-h post-administration and <0.5% of the administered dose was cumulatively detected in liver, spleen, intestines or urine at 48 h. Although particle size and coating did not affect tissue accumulation, silver was detected in liver, spleen and kidney of mice administered ionic silver at marginally higher levels than those administered AgNP, suggesting that silver ion may be more bioavailable. Our results suggest that, irrespective of particle size and coating, acute oral exposure to AgNP at doses relevant to potential human exposure is associated with predominantly fecal elimination and is not associated with accumulation in tissue or toxicity. PMID:26305411

  19. Carbon and water flux responses to physiology by environment interactions: a sensitivity analysis of variation in climate on photosynthetic and stomatal parameters

    NASA Astrophysics Data System (ADS)

    Bauerle, William L.; Daniels, Alex B.; Barnard, David M.

    2014-05-01

    Sensitivity of carbon uptake and water use estimates to changes in physiology was determined with a coupled photosynthesis and stomatal conductance ( g s) model, linked to canopy microclimate with a spatially explicit scheme (MAESTRA). The sensitivity analyses were conducted over the range of intraspecific physiology parameter variation observed for Acer rubrum L. and temperate hardwood C3 (C3) vegetation across the following climate conditions: carbon dioxide concentration 200-700 ppm, photosynthetically active radiation 50-2,000 μmol m-2 s-1, air temperature 5-40 °C, relative humidity 5-95 %, and wind speed at the top of the canopy 1-10 m s-1. Five key physiological inputs [quantum yield of electron transport ( α), minimum stomatal conductance ( g 0), stomatal sensitivity to the marginal water cost of carbon gain ( g 1), maximum rate of electron transport ( J max), and maximum carboxylation rate of Rubisco ( V cmax)] changed carbon and water flux estimates ≥15 % in response to climate gradients; variation in α, J max, and V cmax input resulted in up to ~50 and 82 % intraspecific and C3 photosynthesis estimate output differences respectively. Transpiration estimates were affected up to ~46 and 147 % by differences in intraspecific and C3 g 1 and g 0 values—two parameters previously overlooked in modeling land-atmosphere carbon and water exchange. We show that a variable environment, within a canopy or along a climate gradient, changes the spatial parameter effects of g 0, g 1, α, J max, and V cmax in photosynthesis- g s models. Since variation in physiology parameter input effects are dependent on climate, this approach can be used to assess the geographical importance of key physiology model inputs when estimating large scale carbon and water exchange.

  20. Influence of process parameter variation on the reflectivity of sputter-deposited W-C multilayer diffraction gratings

    NASA Technical Reports Server (NTRS)

    Sager, B.; Benson, P.; Jahoda, K.; Jacobs, J. R.; Bloch, J. J.

    1986-01-01

    Multilayer W-C diffraction gratings with nominal d spacings of 35 A have been fabricated by magnetron sputter deposition. The peak and integrated reflectivities of these films have been measured with Al K-alpha X-rays and compared to theoretical values. The rms surface roughness has been evaluated. The influence of several sputtering-system process parameters on the reflectivities has been investigated.

  1. The effect of wind and eruption source parameter variations on tephra fallout hazard assessment: an example from Vesuvio (Italy)

    NASA Astrophysics Data System (ADS)

    Macedonio, Giovanni; Costa, Antonio; Scollo, Simona; Neri, Augusto

    2015-04-01

    Uncertainty in the tephra fallout hazard assessment may depend on different meteorological datasets and eruptive source parameters used in the modelling. We present a statistical study to analyze this uncertainty in the case of a sub-Plinian eruption of Vesuvius of VEI = 4, column height of 18 km and total erupted mass of 5 × 1011 kg. The hazard assessment for tephra fallout is performed using the advection-diffusion model Hazmap. Firstly, we analyze statistically different meteorological datasets: i) from the daily atmospheric soundings of the stations located in Brindisi (Italy) between 1962 and 1976 and between 1996 and 2012, and in Pratica di Mare (Rome, Italy) between 1996 and 2012; ii) from numerical weather prediction models of the National Oceanic and Atmospheric Administration and of the European Centre for Medium-Range Weather Forecasts. Furthermore, we modify the total mass, the total grain-size distribution, the eruption column height, and the diffusion coefficient. Then, we quantify the impact that different datasets and model input parameters have on the probability maps. Results shows that the parameter that mostly affects the tephra fallout probability maps, keeping constant the total mass, is the particle terminal settling velocity, which is a function of the total grain-size distribution, particle density and shape. Differently, the evaluation of the hazard assessment weakly depends on the use of different meteorological datasets, column height and diffusion coefficient.

  2. Variation of Water Quality Parameters with Siltation Depth for River Ichamati Along International Border with Bangladesh Using Multivariate Statistical Techniques

    NASA Astrophysics Data System (ADS)

    Roy, P. K.; Pal, S.; Banerjee, G.; Biswas Roy, M.; Ray, D.; Majumder, A.

    2014-12-01

    River is considered as one of the main sources of freshwater all over the world. Hence analysis and maintenance of this water resource is globally considered a matter of major concern. This paper deals with the assessment of surface water quality of the Ichamati river using multivariate statistical techniques. Eight distinct surface water quality observation stations were located and samples were collected. For the samples collected statistical techniques were applied to the physico-chemical parameters and depth of siltation. In this paper cluster analysis is done to determine the relations between surface water quality and siltation depth of river Ichamati. Multiple regressions and mathematical equation modeling have been done to characterize surface water quality of Ichamati river on the basis of physico-chemical parameters. It was found that surface water quality of the downstream river was different from the water quality of the upstream. The analysis of the water quality parameters of the Ichamati river clearly indicate high pollution load on the river water which can be accounted to agricultural discharge, tidal effect and soil erosion. The results further reveal that with the increase in depth of siltation, water quality degraded.

  3. Busulfan kinetics.

    PubMed

    Ehrsson, H; Hassan, M; Ehrnebo, M; Beran, M

    1983-07-01

    Busulfan kinetics were studied in patients with chronic myelocytic leukemia after oral doses of 2, 4, and 6 mg. The plasma concentration-time data could be fitted to a zero-order absorption one-compartment open model. The elimination rate constant averaged 0.27 +/- 0.05 hr-1 (SD). The plasma AUC was linearly related to the dose. The lag time for the start of absorption, the time absorption ends, and the absorption rate constant showed some interindividual variations. About 1% of busulfan is excreted unchanged in urine over 24 hr. PMID:6574831

  4. Can the monitoring of animal welfare parameters predict pork meat quality variation through the supply chain (from farm to slaughter)?

    PubMed

    Rocha, L M; Velarde, A; Dalmau, A; Saucier, L; Faucitano, L

    2016-01-01

    The objective of this study was to assess the relationship between the animal welfare conditions evaluated through the supply chain and pork quality variation. A total of 4,680 pigs from 12 farms-5 animal welfare improved raising system (AWIRS) and 7 conventional raising system (CON) farms-were assessed from farm to slaughter through a comprehensive audit protocol merging the European Welfare Quality, the Canadian Animal Care Assessment, and American Meat Institute audit guide criteria. At the abattoir, a subsample of 1,440 pigs (120 pigs/farm) was randomly chosen out of 24 loads (2 farms per wk) transported by 2 drivers (driver A and driver B) for the assessment of stunning effectiveness, carcass bruises, blood lactate levels, and meat quality traits. Meat quality was assessed in the longissimus lumborum (LL) muscle 24 h postmortem by measuring ultimate pH (pHu), color (L*, a*, and b*), and drip loss. Data were analyzed by the MIXED, GLIMMIX, and NAPAR1WAY procedures of SAS. Spearman correlations were calculated to determine the relationship between audit scores and meat quality traits. Better animal welfare conditions, as showed by greater final scores for good housing (GHo; = 0.001) and good health ( = 0.006) principles, were recorded at AWIRS farms. Pigs from AWIRS farms handled by driver B displayed a greater percentage of turning back ( = 0.01) and slips ( < 0.001) during unloading and a greater ( = 0.02) frequency of falls in the stunning chute. A greater ( = 0.02) reluctance to move at loading was found in CON pigs loaded by driver A compared with driver B, whereas a greater ( < 0.001) reluctance to move was found in these pigs at unloading when they were unloaded by driver B. Drip loss was higher ( = 0.003) and pale, soft, and exudative pork percentage was greater ( < 0.001) in the LL muscle of the heavier AWIRS pigs. The GHO principle was best correlated with pHu ( = -0.75, = 0.01) and Minolta L* value ( = 0.87, < 0.001) of the LL muscle. Overall, drip

  5. Biohydrogen production based on the evaluation of kinetic parameters of a mixed microbial culture using glucose and fruit-vegetable waste as feedstocks.

    PubMed

    Garcia-Peña, E I; Canul-Chan, M; Chairez, I; Salgado-Manjarez, E; Aranda-Barradas, J

    2013-09-01

    Hydrogen (H2) production from the organic fraction of solid waste such as fruit and vegetable waste (FVW) is a novel and feasible energy technology. Continuous application of this process would allow for the simultaneous treatment of organic residues and energy production. In this study, batch experiments were conducted using glucose as substrate, and data of H2 production obtained were successfully adjusted by a logistic model. The kinetic parameters (μ max = 0.101 h(-1), K s = 2.56 g/L) of an H2-producing microbial culture determined by the Monod and Haldane-Andrews growth models were used to establish the continuous culture conditions. This strategy led to a productive steady state in continuous culture. Once the steady state was reached in the continuous reactor, a maximum H2 production of 700 mL was attained. The feasibility of producing H2 from the FVW obtained from a local market in Mexico City was also evaluated using batch conditions. The effect of the initial FVW concentration on the H2 production and waste organic material degradation was determined. The highest H2 production rate (1.7 mmol/day), the highest cumulative H2 volume (310 mL), and 25 % chemical oxygen demand (COD) removal were obtained with an initial substrate (FVW) concentration of 37 g COD/L. The lowest H2 production rates were obtained with relatively low initial substrate concentrations of 5 and 11 g COD/L. The H2 production rates with FVW were also characterized by the logistic model. Similar cumulative H2 production was obtained when glucose and FVW were used as substrates. PMID:23832860

  6. Biosorption of Cr(VI) by Ceratocystis paradoxa MSR2 Using Isotherm Modelling, Kinetic Study and Optimization of Batch Parameters Using Response Surface Methodology

    PubMed Central

    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

  7. On fast reactor kinetics studies

    SciTech Connect

    Seleznev, E. F.; Belov, A. A.; Matveenko, I. P.; Zhukov, A. M.; Raskach, K. F.

    2012-07-01

    The results and the program of fast reactor core time and space kinetics experiments performed and planned to be performed at the IPPE critical facility is presented. The TIMER code was taken as computation support of the experimental work, which allows transient equations to be solved in 3-D geometry with multi-group diffusion approximation. The number of delayed neutron groups varies from 6 to 8. The code implements the solution of both transient neutron transfer problems: a direct one, where neutron flux density and its derivatives, such as reactor power, etc, are determined at each time step, and an inverse one for the point kinetics equation form, where such a parameter as reactivity is determined with a well-known reactor power time variation function. (authors)

  8. Discrimination of inland and coastal dunes in Eastern Saudi Arabia desert system: An approach from particle size and textural parameter variations

    NASA Astrophysics Data System (ADS)

    Koeshidayatullah, Ardiansyah; Chan, Septriandi Asmaidi; Al-Ghamdi, Majed; Akif, Tariq; Al-Ramadan, Khalid

    2016-05-01

    Different particle size parameters have been investigated in this study in order to distinguish the characteristics of different dune morphologies in the Eastern Saudi Arabia. Sand samples were collected from various environments including: the stoss, lee, crest and interdune sides of the inland dunes and foreshore; berm; backshore and backdune of the coastal dunes. Statistical parameters reveal that the majority of inland dune samples are dominated by well sorted fine sand whereas coastal dune samples are mainly dominated by very coarse to medium sand, ranging from well sorted to moderately sorted with a low percentage of silt and clay. The presence of relatively coarser grains in the coastal dunes might be explained by continuous wind deflation along the coast together with wave and tidal activities that concentrate coarser grains. Cross-plots from four statistical parameters and supported by the ANOVA test clearly distinguish the particle variations between these dunes. The log-probability analysis suggest that the main transport mechanism in inland and coastal dunes is dominated by the saltation population, comprising up to 80 percent of the distribution. However, the coastal dunes suspension population is mostly belonging to coarser grained material, whereas the inland dunes population is finer. In comparison with particle size characteristics of dunes in the region, the current study shows a close relationship to mean particle size in Iraq, but is relatively finer compared to the Kuwait dunes. This similarity and difference in particle size variation is mostly controlled by the proximity to the coast and also the wind energy and variation in the wind direction.

  9. Short communication: Variation in production parameters among Canadian Holstein cows classified as high, average, and low immune responders.

    PubMed

    Stoop, C L; Thompson-Crispi, K A; Cartwright, S L; Mallard, B A

    2016-06-01

    Dairy cattle evaluated for immune responses and identified as high responders are known to have a lower occurrence of economically important diseases, including mastitis, metritis, ketosis, and retained placenta. These high immune responders have also been shown to make more antibody following vaccination and to have improved milk and colostrum quality. Therefore, breeding for improved immune response is expected to have several benefits in the dairy industry. However, a concern of such an approach to improve animal health is the potential cost of lost production due to an allocation of host resources to mount a robust immune response. The objective of this study was to evaluate early- and late-lactation production parameters in cattle classified as having high, average, or low estimated breeding values (EBV) for cell-mediated (CMIR), antibody-mediated (AMIR), and overall immune responses. A total of 561 cows from 6 herds were phenotyped for immune response and ranked based on EBV for CMIR and AMIR. A linear animal model was used to evaluate differences in milk, fat, and protein yields among immune response groups, and a regression analysis was conducted based on immune response EBV. Overall, no difference in production parameters was found based on immune response rank; however, some positive relationships with immune response EBV were found, suggesting that breeding for enhanced immune responsiveness as a prophylactic approach to improve animal health would not come at the cost of lost production. PMID:27060821

  10. Noontime Latitudinal Behavior of the Ionospheric Peak Parameters (foF2 and hmF2) to the Variation of Solar Energy Input for the American Sector

    NASA Astrophysics Data System (ADS)

    Cabassa-Miranda, E.; Garnett Marques Brum, C.

    2013-12-01

    We are presenting a statistical study of the behavior of the noontime F2 peak parameters (foF2 and hmF2) to the variation of solar energy input based on digisonde data and EUV-UV solar emissions registered by SOHO satellite for geomagnetic quiet-to-normal condition. For this, we selected digisonde data from fourteen different stations spread along the American sector (ten of them located above and four below the equator). These registers were collected from 2000 to 2012 and encompass the last unusual super minimum period.

  11. TWENTY-ONE NEW LIGHT CURVES OF OGLE-TR-56b: NEW SYSTEM PARAMETERS AND LIMITS ON TIMING VARIATIONS

    SciTech Connect

    Adams, E. R.; Holman, M. J.; Lopez-Morales, M.; Elliot, J. L.; Seager, S.; Osip, D. J.; Winn, J. N.; Hoyer, S.; Rojo, P.

    2011-11-10

    Although OGLE-TR-56b was the second transiting exoplanet discovered, only one light curve, observed in 2006, has been published besides the discovery data. We present 21 light curves of 19 different transits observed between 2003 July and 2009 July with the Magellan Telescopes and Gemini South. The combined analysis of the new light curves confirms a slightly inflated planetary radius relative to model predictions, with R{sub p} = 1.378 {+-} 0.090 R{sub J} . However, the values found for the transit duration, semimajor axis, and inclination values differ significantly from the previous result, likely due to systematic errors. The new semimajor axis and inclination, a = 0.01942 {+-} 0.00015 AU and i = 73.{sup 0}72 {+-} 0.{sup 0}18, are smaller than previously reported, while the total duration, T{sub 14} = 7931 {+-} 38 s, is 18 minutes longer. The transit midtimes have errors from 23 s to several minutes, and no evidence is seen for transit midtime or duration variations. Similarly, no change is seen in the orbital period, implying a nominal stellar tidal decay factor of Q{sub *} = 10{sup 7}, with a 3{sigma} lower limit of 10{sup 5.7}.

  12. Pair Identity and Smooth Variation Rules Applicable for the Spectroscopic Parameters of H2O Transitions Involving High-J States

    NASA Technical Reports Server (NTRS)

    Ma, Q.; Tipping, R. H.; Lavrentieva, N. N.

    2010-01-01

    Two basic rules (i.e. the pair identity and the smooth variation) applicable for H2O transitions involving high-J states have been discovered. The origins of these rules are the properties of the energy levels and wavefunctions of H2O states with the quantum number J above certain boundaries. As a result, for lines involving high-J states in individually defined groups, all their spectroscopic parameters (i.e. the transition wavenumber, intensity, pressure-broadened half-width, pressure-induced shift, and temperature exponent) must follow these rules. One can use these rules to screen spectroscopic data provided by databases and to identify possible errors. In addition, by using extrapolation methods within the individual groups, one is able to predict the spectroscopic parameters for lines in this group involving very high-J states. The latter are required in developing high-temperature molecular spectroscopic databases such as HITEMP.

  13. Contribution of long-term accounting for raindrop size distribution variations on quantitative precipitation estimation by weather radar: Disdrometers vs parameter optimization

    NASA Astrophysics Data System (ADS)

    Hazenberg, P.; Uijlenhoet, R.; Leijnse, H.

    2015-12-01

    Volumetric weather radars provide information on the characteristics of precipitation at high spatial and temporal resolution. Unfortunately, rainfall measurements by radar are affected by multiple error sources, which can be subdivided into two main groups: 1) errors affecting the volumetric reflectivity measurements (e.g. ground clutter, vertical profile of reflectivity, attenuation, etc.), and 2) errors related to the conversion of the observed reflectivity (Z) values into rainfall intensity (R) and specific attenuation (k). Until the recent wide-scale implementation of dual-polarimetric radar, this second group of errors received relatively little attention, focusing predominantly on precipitation type-dependent Z-R and Z-k relations. The current work accounts for the impact of variations of the drop size distribution (DSD) on the radar QPE performance. We propose to link the parameters of the Z-R and Z-k relations directly to those of the normalized gamma DSD. The benefit of this procedure is that it reduces the number of unknown parameters. In this work, the DSD parameters are obtained using 1) surface observations from a Parsivel and Thies LPM disdrometer, and 2) a Monte Carlo optimization procedure using surface rain gauge observations. The impact of both approaches for a given precipitation type is assessed for 45 days of summertime precipitation observed within The Netherlands. Accounting for DSD variations using disdrometer observations leads to an improved radar QPE product as compared to applying climatological Z-R and Z-k relations. However, overall precipitation intensities are still underestimated. This underestimation is expected to result from unaccounted errors (e.g. transmitter calibration, erroneous identification of precipitation as clutter, overshooting and small-scale variability). In case the DSD parameters are optimized, the performance of the radar is further improved, resulting in the best performance of the radar QPE product. However

  14. Recent variations of the nivo - thermic parameters in the territory of the Dolomites and venetian Prealps Recent variations of the nivo - thermic parameters in the territory of the Dolomites and venetian Prealps

    NASA Astrophysics Data System (ADS)

    Fazzini, Massimiliano; Cagnati, Anselmo; Camattari, Serena

    2016-04-01

    The analysis of recent snowfalls in the medium - high mountain areas of the Mediterranean basin, is considered as an important tool to evaluate the underway climatic change. Aim of the study was to define the space - altitudinal distribution of snowfall and temperatures and to outline the recent trend, considering the signal defined by similar recent studies in the Alps, which show a general decrease in of snowfall and an increase significant of temperatures. It was therefore considered monthly and seasonal thermo - nivometric data - relating to fifteen automatic measurement stations - operated by ARPAV - located at altitudes between approximately 1430 and 2620 ma.s.l. and activated during the second half of the 80s. The study area is extended for about 5000 sqkm. The parameters analysed were: cumulated of fresh snow, snowy days (with Hn> 1cm), continued persistence of snow on the ground and average air temperatures. in this area, at about 2000 meters, an average of 360 cm of seasonal fresh snow - between November and May - are recorded; the snow remains on the ground for about 190 days and there are about 50 days with snowfall (hn> 1cm). Fresh snow increases, on average, of about 18 cm and remains down 8.5 in addition, each 100 meters of altitude. Finally, the average annual temperature is of about 2,8° C, with an elevation of 0° C at 2780 m a.s.l. The nivometric and thermometric trend shows a quite surprising evidences; both as regards the fresh snow for both snowy days, there was a general increase - resulting from some recent seasons very snowy - while with regard to the persistence of the snow on the ground, a signal more contrasted is evident. Temperatures show a marked increase - about 1.5° C - in the pre-Alps, while in the Dolomites, the temperatures tend widely to decline by about 0.5° C. Given the particularities of these results, it would be essential to extend the study area at the entire Venice Tridentine mountains, to understand if these signals

  15. Intrinsic parameters for structural variation of reverse micelles in nonionic surfactant (glycerol alpha-monolaurate)/oil systems: a SAXS study.

    PubMed

    Shrestha, Lok Kumar; Sato, Takaaki; Aramaki, Kenji

    2009-06-01

    Using Small-Angle X-ray scattering (SAXS), we have studied self-assembled structures of glycerol alpha-monolaurate (C(12)G(1)) in different nonpolar solvents, such as cyclohexane, n-octane, n-decane, n-tetradecane, and n-hexadecane, as a function of composition, temperature, and added polar additives. The dilute mixtures of C(12)G(1) with the aforementioned oils are essentially a solid dispersion at lower temperatures without forming any liquid crystalline phases, which are transformed into isotropic reverse micellar solutions upon heating. The generalized indirect Fourier transformation (GIFT) analysis of the SAXS data has drawn a clear picture of the structural variations of the reverse micellar aggregates in the isotropic solution phase. A notable effect on the micellar growth emerges when cyclohexane is replaced with the linear-chain hydrocarbon oils; a gradual increase of the carbon number of the hydrocarbon skeleton from octane to hexadecane, ellipsoidal prolate-like micelles are eventually transformed to long rod-like ones. Far more pronounced structural enhancement could be achieved by increasing the hydrophilicity of the surfactant, as short-rod micelles observed in the C(12)G(1)/decane system are replaced with long cylindrical ones when a more hydrophilic diglycerol monolaurate (C(12)G(2)) is used. This fact also supports a scenario that regulates the ability to form elongated to reverse structures. Lowering the temperature and increasing the surfactant concentration similarly lead to micellar growth while the cross-sectional structure remains essentially unchanged. In contrast, polar additive-induced growth is accompanied by the rapid swelling of the micellar core. Our data demonstrate that optimization of the oil properties and/or other outer conditions provide possible routes to flexibly controlling the size, shape, and internal structure of the reverse micelles despite lower universality for a shorter hydrophilic chain surfactant. PMID:19458827

  16. Effect of sampling site and collection method on variations in baseline clinical pathology parameters in Fischer-344 rats. 1. Clinical chemistry.

    PubMed

    Neptun, D A; Smith, C N; Irons, R D

    1985-12-01

    An analysis of the influence of blood sampling site and collection method on clinical chemistry parameters was conducted in male Fischer-344 rats. Sampling sites compared included the right ventricle, aorta, vena cava, retroorbital sinus, and tail. Methods of collection included Vacutainer (3 ml sample), syringe (exsanguination), and capillary tube. Nineteen frequently measured clinical chemistry procedures were determined, including serum enzymes, cholesterol, and triglycerides. Significant differences were noted for almost every parameter as a function of sampling site. Samples collected from the right ventricle with a Vacutainer produced the most representative results for most but not all procedures when compared to the overall mean (for all methods). The largest differences were encountered in samples obtained from tail and retroorbital plexus. Exanguination also resulted in significant differences for some parameters when compared to smaller sample volumes obtained from the same site. It was concluded that sampling site and collection method can be a major source of variation in clinical chemistry measurements, and in selection of an appropriate method, one should consider which parameters are likely to be of major interest. PMID:4092880

  17. Hematological parameters and the variations resulting from stress of Alouatta caraya during a wildlife rescue program in Brazil.

    PubMed

    Sánchez-Sarmiento, Angélica María; Zwarg, Ticiana; Fernandes-Santos, Renata Carolina; Guimarães-Luiz, Thaís; Genoy-Puerto, Alexander; Matushima, Eliana Reiko

    2015-03-01

    Deforestation and habitat fragmentation are major threats to the conservation status of New World primates, such as the howler monkey (Alouatta caraya) in Brazil, where vegetation destruction is often associated with projects such as Small Hydro Power Plant (SHP) construction. The resulting stress from the implementation of this type of enterprise may be a factor that influences individual susceptibility against pathogens and can determine the success or failure of mitigation measures proposed by responsible and/or requested companies by environmental agencies. To perform health monitoring and to understand physiological changes that ensued from the stress of capturing and keeping primates in captivity, we determined the blood profile of A. caraya rescued at the time of capture (N = 15) and in captivity (N = 11). Complete blood counts (CBCs) performed at the time of capture showed hematological changes compatible with acute stress, such as evident neutrophilic leukocytosis (WBCs; females = 20.48 ± 7.26; males = 18.78 ± 10.39 × 10(9) /L). In captivity, monocytosis was observed in both sexes (females = 1.34 ± 0.26; males = 0.39 ± 0.32 × 10(9) /L; U-test, P = 0.01), suggesting chronic stress. In females, there was also statistically significant eosinopenia (0.28 ± 0.10 × 10(9) /L; U-test, P = 0.01) and hematocrit increases (39.00 ± 1.41%; U-test, P = 0.01). Thus, data shows the impact of both capture related acute stress as well as captivity chronic stress, suggesting that primate management in the implementation of these projects causes significant changes in physiological parameters and, consequently, animal health. Whereas chronic stress is an inducer of immunosuppression and susceptibility to pathogen factors, monitoring hematological parameters in captive animals can act as an indicator of health status, contributing to the success of management and conservation wildlife programs. Am

  18. Recognizing and analyzing variability in amyloid formation kinetics: Simulation and statistical methods.

    PubMed

    Hall, Damien; Zhao, Ran; So, Masatomo; Adachi, Masayuki; Rivas, Germán; Carver, John A; Goto, Yuji

    2016-10-01

    We examine the phenomenon of variability in the kinetics of amyloid formation and detail methods for its simulation, identification and analysis. Simulated data, reflecting intrinsic variability, were produced using rate constants, randomly sampled from a pre-defined distribution, as parameters in an irreversible nucleation-growth kinetic model. Simulated kinetic traces were reduced in complexity through description in terms of three characteristic parameters. Practical methods for assessing convergence of the reduced parameter distributions were introduced and a bootstrap procedure was applied to determine convergence for different levels of intrinsic variation. Statistical methods for assessing the significance of shifts in parameter distributions, relating to either change in parameter mean or distribution shape, were tested. Robust methods for analyzing and interpreting kinetic data possessing significant intrinsic variance will allow greater scrutiny of the effects of anti-amyloid compounds in drug trials. PMID:27430932

  19. Cross-laboratory comparative study of the impact of experimental and regression methodologies on salmonella thermal inactivation parameters in ground beef

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Isothermal inactivation studies are commonly used to quantify thermal inactivation kinetics of bacteria. Meta-analyses and comparisons utilizing results from multiple sources have revealed large variations in reported inactivation parameters for Salmonella, even in similar food materials. Different ...

  20. Study of variations in structural, optical parameters and bulk etch rate of CR-39 polymer due to electron irradiation

    NASA Astrophysics Data System (ADS)

    Sahoo, G. S.; Tripathy, S. P.; Joshi, D. S.; Bandyopadhyay, T.

    2016-07-01

    In this work, electron induced modifications on the bulk etch rate, structural and optical parameters of CR-39 polymer were studied using gravimetric, FTIR (Fourier Transform Infrared) and UV-vis (Ultraviolet-Visible) techniques, respectively. CR-39 samples were irradiated with 10 MeV electron beam for different durations to have the absorbed doses of 1, 10, 550, 5500, 16 500, and 55 000 kGy. From the FTIR analysis, the peak intensities at different bands were found to be changing with electron dose. A few peaks were observed to shift at high electron doses. From the UV-vis analysis, the optical band gaps for both direct and indirect transitions were found to be decreasing with the increase in electron dose whereas the opacity, number of carbon atoms in conjugation length, and the number of carbon atoms per cluster were found to be increasing. The bulk etch rate was observed to be increasing with the electron dose. The primary objective of this investigation was to study the response of CR-39 to high electron doses and to determine a suitable pre-irradiation condition. The results indicated that, the CR-39 pre-irradiated with electrons can have better sensitivity and thus can be potentially applied for neutron dosimetry.

  1. Growth Parameters, Photosynthetic Performance, and Biochemical Characterization of Newly Isolated Green Microalgae in Response to Culture Condition Variations.

    PubMed

    Jazzar, Souhir; Berrejeb, Nadia; Messaoud, Chokri; Marzouki, Mohamed Néjib; Smaali, Issam

    2016-08-01

    This work aimed to characterize two native microalgal strains newly isolated from South Mediterranean areas and identified as Chlorella sorokiniana ES3 and Neochloris sp. AM2. The growth properties and biochemical composition of these microalgae were evaluated in different culture media (Algal, BG-11, f/2, and Conway). Among the tested media, nitrate- and phosphate-rich Algal medium provided the maximum biomass productivities (85.5 and 111.5 mg l(-1) day(-1) for C. sorokiniana and Neochloris sp., respectively), while the nitrate- and phosphate-deficient f/2 medium resulted in the highest lipid productivities (24.1 and 35.8 mg l(-1) day(-1) for C. sorokiniana and Neochloris sp., respectively). The physiological state of both microalgae was investigated under different light and temperature levels using the pulse amplitude-modulated fluorometry. The better photosynthetic efficiency of C. sorokiniana was obtained at 23 °C with a light saturation of 156 μE m(-2) s(-1), while that of Neochloris sp. was achieved at 15 °C with a light saturation of 151 μE m(-2) s(-1). The analysis of fatty acid profile and biodiesel parameters revealed that C. sorokiniana, cultivated in Algal and f/2 media, can be considered as a suitable candidate for high-quality biodiesel production. PMID:27052210

  2. Variation in antioxidant enzyme activities, growth and some physiological parameters of bitter melon (Momordica charantia) under salinity and chromium stress.

    PubMed

    Bahrami, Mahsa; Heidari, Mostafa; Ghorbani, Hadi

    2016-07-01

    In general, salinity and heavy metals interfere with several physiological processes and reduce plant growth. In order to evaluate of three levels of salinity (0, 4 and 8 ds m(-1)) and three concentration of chromium (0, 10 and 20 mg kg(-1) soil) in bitter melon (Momordica charantia), a plot experiment was conducted in greenhouse at university of Shahrood, Iran. The results revealed that chromium treatment had no significant affect on fresh and dry weight, but salinity caused reduction of fresh and dry weight in growth parameter. Salinity and chromium enhanced antioxidant enzymes activities like catalase (CAT), guaiacol peroxidase (GPX) and sodium content in leaves. However salinity and chromium treatments had no effect on potassium, phosphorus in leaves, soluble carbohydrate concentration in leaves and root, but decreased the carotenoid content in leaves. On increasing salinity from control to 8 ds m(-1) chlorophyll a, b and anthocyanin content decreased by 41.6%, 61.1% and 26.5% respectively but chromium treatments had no significant effect on these photosynthetic pigments. PMID:27498497

  3. Seasonal variations in vibrational spectra of the sea surface nanolayer and their relation to characteristic parameters for phytoplankton activity

    NASA Astrophysics Data System (ADS)

    Laß, Kristian; Bange, Hermann W.; Friedrichs, Gernot

    2013-04-01

    The sea surface nanolayer is a very thin organic substance layer, down to monomolecular thickness. It is found on top of the sea surface microlayer, which in turn comprises roughly the uppermost millimeter of the water column. The nanolayer constitutes the actual interface between ocean and atmosphere and plays an important role in all exchange processes of matter and energy between ocean and atmosphere. Nevertheless, knowledge about formation and development of the sea surface nanolayer in the course of the year is very limited. In this study we present surface-specific observations of the sea surface nanolayer development over a period of three and a half years. Samples of the sea surface have been taken monthly at Boknis Eck Time Series Station (Eckernförde Bay, southwestern Baltic Sea) by screen sampling. From surface-sensitive vibrational spectra obtained by nonlinear sum frequency generation spectroscopy (SFG), information on amount, structure and composition of the organic nanolayer material was extracted. SFG has been introduced by us as a new method to study the ocean nanolayer quite recently [1,2]. The abundance of nanolayer material was found to follow a pronounced yearly periodicity, with larger amounts of material present from mid to end of summer. A substantial time lag of about 2.5 months between spring algal bloom maxima and abundance maxima of nanolayer material has been observed. In contrast to common perception, this shows that high phytoplankton abundance and pronounced nanolayers are not directly related to each other. Variations in the appearance of the spectra serve as indicators for changes in structure and chemical composition of the nanolayer. The accumulation of carbohydrate-rich material in late summer provides a possible explanation for the observed spectral changes. We propose that sloppy feeding of zooplankton as well as photochemical and/or microbial processing of organic material present in the microlayer is responsible for the

  4. Variations of biochemical parameters along a transect in the Southern Ocean, with special emphasis on volatile halogenated organic compounds

    NASA Astrophysics Data System (ADS)

    Abrahamsson, K.; Bertilsson, S.; Chierici, M.; Fransson, A.; Froneman, P. W.; Lorén, A.; Pakhomov, E. A.

    2004-11-01

    A number of parameters of biogeochemical interest were monitored along a north-southerly transect (S 43-S 63°) in the Atlantic Sector of the Southern Ocean from the 8th to the 20th of December 1997. Changes in total dissolved inorganic carbon ( CT) and total alkalinity ( AT) were mostly dependent on temperature and salinity until the ice edge was reached. After this point only a weak correlation was seen between these. Highest mean values of CT and AT were observed in the Winter Ice Edge (WIE) (2195 and 2319 μmol kg -1, respectively). Lowest mean AT (2277 μmol kg -1) was observed in the Sub-Antarctic Front (SAF), whereas lowest mean CT concentration (2068 μmol kg -1) was associated with the Sub-Tropical Front (STF). The pH in situ varied between 8.060 and 8.156 where the highest values were observed in the southern part of the Antarctic Polar Front (APF) and in the Summer Ice Edge (SIE) Region . These peaks were associated with areas of high chlorophyll a (chl a) and tribromomethane values. In the other areas the pH in situ was mainly dependent on hydrography. Bacterial abundance decreased more than one order of magnitude when going from north to south. The decrease appeared to be strongly related to water temperature and there were no elevated abundances at frontal zones. Microphytoplankton dominated in the SAF and APF, whereas the nano- and picoplankton dominated outside these regions. Volatile halogenated compounds were found to vary both with regions, and with daylight. For the iodinated compounds, the highest concentrations were found north of the STF. Brominated hydrocarbons had high concentrations in the STF, but elevated concentrations were also found in the APF and SIE regions. No obvious correlation could be found between the occurrence of individual halocarbons and chl a. On some occasions trichloroethene and tribromomethane related to the presence of nano- and microplankton, respectively.

  5. New kinetic parameters for rat liver arginase measured at near-physiological steady-state concentrations of arginine and Mn2+.

    PubMed Central

    Maggini, S; Stoecklin-Tschan, F B; Mörikofer-Zwez, S; Walter, P

    1992-01-01

    A cytosolic cell-free system from rat liver containing the last three enzymes of the urea cycle, a number of cofactors and the substrates aspartate and citrulline was shown to synthesize urea at near-physiological rates ranging between 0.40 and 1.25 mumol/min per g of liver. This system was used to determine the kinetic parameters for arginase. With saturating amounts of Mn2+ (30 microM), arginine remained at a steady-state concentration of 5-35 microM depending on the aspartate and citrulline supply. Vmax. at micromolar arginine concentrations was between 1.10 and 1.25 mumol/min per g of liver, the K0.5 (arginine) between 6.0 and 6.5 microM and positive co-operativity was observed (Hill coefficient 2). Omission of Mn2+ caused a significant accumulation of arginine during the incubation, suggesting a regulatory effect of arginase. Under these conditions, Vmax. was 1.10-1.65 mumol/min per g of liver and the Km (arginine) increased up to 14.4-21.1 microM. The apparent Ka for Mn2+ in the presence of physiological concentrations of ATP, Mg2+ and arginine was calculated to be maximally 8 microM. Initial-velocity experiments with millimolar arginine concentrations as the direct substrate gave the following results, which are in good agreement with literature data. In the absence of Mn2+, Vmax. was 71.3 mumol/min per g of liver and the Km (arginine) 1.58 mM. With 30 microM-Mn2+, Vmax. was 69.4 mumol/min per g of liver and the Km (arginine) decreased to 0.94 mM. On the basis of our results, we propose the presence of high-affinity and low-affinity sites for arginine on rat liver arginase and postulate that alterations in arginase activity arising from changes in the concentration of arginine and of the cofactor Mn2+ may contribute to the regulation of ureagenesis in vivo. PMID:1590754

  6. Kinetics of improved 1,4-alpha-D-glucan glucohydrolase biosynthesis from a newly isolated Aspergillus oryzae IIB-6 and parameter significance analysis by 2-factorial design.

    PubMed

    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). PMID:23961361

  7. Assessment of soil electromagnetic parameters and their variation with soil water, salts: a comparison among EMI and TDR measuring methods

    NASA Astrophysics Data System (ADS)

    Chaali, Nesrine; Coppola, Antonio; Comegna, Alessandro; Dragonetti, Giovanna

    2015-04-01

    Numerous studies have analyzed the possibility of the extension of Electromagnetic Induction EMI calibration coefficients determined at field scale, to predict the depth distribution of bulk electrical conductivity ECb within unmonitored sites and/or times, in order to appraise the effect of salts dynamics on soils and plants. However, in the literature, it has been determined that the extension of those EMI calibration coefficients can be awkward since the calibration parameters are highly site-specific because of changes in water content, temperature, root development, soil physical properties, etc... So they can only be used in sites having similar characteristics in terms of EMI. Furthermore there is a difference in the observation windows of EMI sensors and of sensors (Time Domain Reflectometry TDR, Electrical Resistance Tomography ERT, ect...) used for measuring the ECb to be then used for the calibration and validation of the EMI. By consequence the actual variability of the soil salinity will be hidden due to the fact that data coming from EMI and other sensors have different variability patterns and structure, and are then influenced by different noises. The main objectives of this work were: 1) develop a practical and cost-effective technique that uses TDR data as ground-truth data for calibrating and validating of the EMI larger scale sensor, 2) using a Fourier transform FT analysis by applying a specific noise filter to the original data, to find the correlations between the TDR and the EMI data. An experiment was designed by irrigating three transects of green beans, 30 m long each, with three irrigation salinity inputs (1dSm-1, 3dSm-1, 6dSm-1). The irrigation volumes were estimated by measuring soil water content at different depths by using a Diviner 2000. During the experiment, the EM in both the vertical (EMV) and horizontal (EMH) configurations were regularly measured by a Geonics EM38 device. TDR probes were inserted vertically at the soil

  8. Analysis of Family Structures Reveals Robustness or Sensitivity of Bursting Activity to Parameter Variations in a Half-Center Oscillator (HCO) Model

    PubMed Central

    2016-01-01

    The underlying mechanisms that support robustness in neuronal networks are as yet unknown. However, recent studies provide evidence that neuronal networks are robust to natural variations, modulation, and environmental perturbations of parameters, such as maximal conductances of intrinsic membrane and synaptic currents. Here we sought a method for assessing robustness, which might easily be applied to large brute-force databases of model instances. Starting with groups of instances with appropriate activity (e.g., tonic spiking), our method classifies instances into much smaller subgroups, called families, in which all members vary only by the one parameter that defines the family. By analyzing the structures of families, we developed measures of robustness for activity type. Then, we applied these measures to our previously developed model database, HCO-db, of a two-neuron half-center oscillator (HCO), a neuronal microcircuit from the leech heartbeat central pattern generator where the appropriate activity type is alternating bursting. In HCO-db, the maximal conductances of five intrinsic and two synaptic currents were varied over eight values (leak reversal potential also varied, five values). We focused on how variations of particular conductance parameters maintain normal alternating bursting activity while still allowing for functional modulation of period and spike frequency. We explored the trade-off between robustness of activity type and desirable change in activity characteristics when intrinsic conductances are altered and identified the hyperpolarization-activated (h) current as an ideal target for modulation. We also identified ensembles of model instances that closely approximate physiological activity and can be used in future modeling studies. PMID:27595135

  9. Analysis of Family Structures Reveals Robustness or Sensitivity of Bursting Activity to Parameter Variations in a Half-Center Oscillator (HCO) Model.

    PubMed

    Doloc-Mihu, Anca; Calabrese, Ronald L

    2016-01-01

    The underlying mechanisms that support robustness in neuronal networks are as yet unknown. However, recent studies provide evidence that neuronal networks are robust to natural variations, modulation, and environmental perturbations of parameters, such as maximal conductances of intrinsic membrane and synaptic currents. Here we sought a method for assessing robustness, which might easily be applied to large brute-force databases of model instances. Starting with groups of instances with appropriate activity (e.g., tonic spiking), our method classifies instances into much smaller subgroups, called families, in which all members vary only by the one parameter that defines the family. By analyzing the structures of families, we developed measures of robustness for activity type. Then, we applied these measures to our previously developed model database, HCO-db, of a two-neuron half-center oscillator (HCO), a neuronal microcircuit from the leech heartbeat central pattern generator where the appropriate activity type is alternating bursting. In HCO-db, the maximal conductances of five intrinsic and two synaptic currents were varied over eight values (leak reversal potential also varied, five values). We focused on how variations of particular conductance parameters maintain normal alternating bursting activity while still allowing for functional modulation of period and spike frequency. We explored the trade-off between robustness of activity type and desirable change in activity characteristics when intrinsic conductances are altered and identified the hyperpolarization-activated (h) current as an ideal target for modulation. We also identified ensembles of model instances that closely approximate physiological activity and can be used in future modeling studies. PMID:27595135

  10. Sensitivity of kinetic macro parameters to changes in dopamine synthesis, storage, and metabolism: a simulation study for [¹⁸F]FDOPA PET by a model with detailed dopamine pathway.

    PubMed

    Matsubara, Keisuke; Watabe, Hiroshi; Kumakura, Yoshitaka; Hayashi, Takuya; Endres, Christopher J; Minato, Kotaro; Iida, Hidehiro

    2011-08-01

    Quantitative interpretation of brain [¹⁸F]FDOPA PET data has been made possible by several kinetic modeling approaches, which are based on different assumptions about complex [¹⁸F]FDOPA metabolic pathways in brain tissue. Simple kinetic macro parameters are often utilized to quantitatively evaluate metabolic and physiological processes of interest, which may include DDC activity, vesicular storage, and catabolism from (18) F-labeled dopamine to DOPAC and HVA. A macro parameter most sensitive to the changes of these processes would be potentially beneficial to identify impaired processes in a neurodegenerative disorder such as Parkinson's disease. The purpose of this study is a systematic comparison of several [¹⁸F]FDOPA macro parameters in terms of sensitivities to process-specific changes in simulated time-activity curve (TAC) data of [¹⁸F]FDOPA PET. We introduced a multiple-compartment kinetic model to simulate PET TACs with physiological changes in the dopamine pathway. TACs in the alteration of dopamine synthesis, storage, and metabolism were simulated with a plasma input function obtained by a non-human primate [¹⁸F]FDOPA PET study. Kinetic macro parameters were calculated using three conventional linear approaches (Gjedde-Patlak, Logan, and Kumakura methods). For simulated changes in dopamine storage and metabolism, the slow clearance rate (k(loss) ) as calculated by the Kumakura method showed the highest sensitivity to these changes. Although k(loss) performed well at typical ROI noise levels, there was large bias at high noise level. In contrast, for simulated changes in DDC activity it was found that K(i) and V(T), estimated by Gjedde-Patlak and Logan method respectively, have better performance than k(loss). PMID:21190220

  11. Lithological Variation with Depth and Decoupling of Maturity Parameters in Apollo 16 Regolith Core 68001/2

    NASA Technical Reports Server (NTRS)

    Korotev, Randy L.; Morris, Richard V.; Jolliff, Bradley L.; Schwarz, Carol

    1997-01-01

    Using FerroMagnetic Resonance (FMR) and Instrumental Neutron Activation Analysis (INAA), we have determined the maturity (surface exposure) parameter I(sub s)/FeO and concentrations of twenty- five chemical elements on samples taken every half centimeter down the 61-cm length of the 68001/2 regolith core (double drive tube) collected at station 8 on the Apollo 16 mission to the Moon. Contrary to premission expectations, no ejecta or other influence from South Ray crater is evident in the core, although a small inflection in the I(sub s)/FeO profile at 3 cm depth may be related the South Ray crater impact. Regolith maturity generally decreases with depth, as in several previously studied cores. We recognize five compositionally distinct units in the core, which we designate A through E, although all are similar in composition to each other and to other soils from the Cayley plains at the Apollo 16 site. Unit A (0-33 cm) is mature to submature throughout (I(sub s)/FeO: 89-34 units) and is indistinguishable in composition from surface soils collected at station 8. Unit B (33-37 cm) is enriched slightly in a component of anorthositic norite composition. Unit D (42-53 cm) is compositionally equivalent to 80 wt% Unit-A soil plus 20 wt% Apollo-16-type dimict breccia consisting of subequal parts anorthosite and impact-melt breccia. Compared to Unit A, Unit E (53-61 cm) contains a small proportion (up to 4%) of some component compositionally similar to Apollo 14 sample 14321. Unit C (37-42 cm) is unusual. For lithophile and siderophile elements, it is similar to Units A and D. However, I(sub s)/FeO is low throughout the unit (less than 30 units) and in a bluish-gray zone at 41 cm depth I(sub s)/FeO drops to 1.6 units, the lowest value that we have observed in several hundred Apollo 16 soil samples. Samples from the bluish-gray zone also have low Zn concentrations, less than 10 micro g/g, compared to 20-30 micro g/g for the rest of the core. Although both values are

  12. Improving the parameters of a global ocean biogeochemical model via variational assimilation of in situ data at five time series stations

    NASA Astrophysics Data System (ADS)

    Kane, A.; Moulin, C.; Thiria, S.; Bopp, L.; Berrada, M.; Tagliabue, A.; CréPon, M.; Aumont, O.; Badran, F.

    2011-06-01

    The global ocean biogeochemical models that are used in order to assess the ocean role in the global carbon cycle and estimate the impact of the climate change on marine ecosystems are getting more and more sophisticated. They now often account for several phytoplankton functional types that play particular roles in marine food webs and the ocean carbon cycle. These phytoplankton functional types have specific physiological characteristics, which are usually poorly known and therefore add uncertainties to model results. Indeed, this evolution in model complexity is not accompanied by a similar increase in the number and diversity of in situ data sets necessary for model calibration and evaluation. Thus, it is of primary importance to develop new methods to improve model performance using existing biogeochemical data sets, despite their current limitations. In this paper, we have optimized 45 physiological parameters of the PISCES global model, using a variational optimal control method. In order to bypass a global 3-D ocean variational assimilation, which would require enormous computation and memory storage, we have simplified the estimation procedure by assimilating monthly climatological in situ observations at five contrasted oceanographic stations of the JGOFS program in a 1-D version of the PISCES model. We began by estimating the weight matrix in the cost function by using heuristic considerations. Then we used this matrix to estimate the 45 parameters of the 1-D version of the PISCES model by assimilating the different monthly profiles (observed profiles at the five stations) in the same variational procedure on a time window of 1 year. This set of optimized parameters was then used in the standard 3-D global PISCES version to perform a 500 year global simulation. The results of both the standard and the optimized versions of the model were compared to satellite-derived chlorophyll-a images, which are an independent and global data set, showing that our

  13. Seasonal and diurnal variations of atmospheric PAHs and OCPs in a suburban paddy field, South China: Impacts of meteorological parameters and sources

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Li, Qilu; Wang, Shaorui; Wang, Yujie; Luo, Chunling; Li, Jun; Zhang, Gan

    2015-07-01

    The atmospheric contaminations of polycyclic aromatic hydrocarbons (PAHs), hexachlorocyclohexanes (HCHs), and DDTs have been extensively monitored for decades, but contaminations in agricultural paddy fields have rarely been reported. We measured the atmospheric PAH, HCH, and DDT constituents during different rice growth stages in a suburban paddy field in South China. Diurnal variations were found in the atmospheric concentrations of PAHs and HCHs, but not for DDTs. Additional nocturnal emissions and meteorological conditions, such as low nocturnal stable atmospheric boundary layers, may be mainly responsible for the higher PAH and HCH levels at night, respectively. Atmospheric concentrations of PAH, HCH, and DDT constituents varied with rice growth stage, but no regular seasonal variation was found, suggesting that rice growth has no significant influence on the atmospheric concentrations of these chemicals. A correlation analysis suggested that meteorological parameters, such as temperature, precipitation, mixing layer height, or wind speed, may directly or indirectly affect the air concentrations of PAHs, HCHs, and DDTs. Source apportionment showed that atmospheric PAHs, HCHs, and DDTs in the paddy field originated from mixed sources, and the contribution of each source varied with time. The isomer ratio of fluoranthene/(fluoranthene + pyrene) may result in an invalid diagnosis of PAHs.

  14. Kinetic analysis of HO{sub 2} addition to ethylene, propene, and isobutene, and thermochemical parameters of alkyl hydroperoxides and hydroperoxide alkyl radicals

    SciTech Connect

    Chen, C.J.; Bozzelli, J.W.

    2000-06-01

    Thermochemical kinetic analysis for the reactions of HO{sub 2} radical addition to the primary, secondary, and tertiary carbon-carbon double bonds of ethylene, propene, and isobutene are studied using canonical transition state theory (TST). Thermochemical properties of reactants, alkyl hydroperoxides (ROOH), hydroperoxy alkyl radicals (R-OOH), and transition states (TSs) are determined by ab initio and density functional calculations. Enthalpies of formation ({Delta}H{sub f 298}{degree}) of product radicals (R-OOH) are determined using isodesmic reactions with group balance at MP4(full)6-31G(d,p)/MP2(full)/6-31G(d), MP2(full)/6-31G(d), complete basis set model chemistry (CBS-q with MP2(full)/6-31g(d) and B3LYP/6-31g(d) optimized geometries), and density functional (B3LYP/6-31g(d) and B3LYP/6-311+g(3df,2p)//B3LYP/6-31g(d)) calculations. {Delta}H{sub f 298}{degree} of TSs are obtained from the {Delta}H{sub f 298}{degree} of reactants plus energy differences between reactants and TSs. Entropies (S{sub 298}{degree}) and heat capacities (Cp(T) 300 {le} T/K {le} 1,500) contributions from vibrational, translational, and external rotational are calculated using the rigid-rotor-harmonic-oscillator approximation based on geometric parameters and vibrational frequencies obtained at MP2(full)/6-31G(d) and B3LYP/6-31G(d) levels of theory. Selected potential barriers of internal rotations for hydroperoxy alkyl radicals and TSs are calculated at MP2(full)/6-31G(d) and CBS-Q//MP2(full)/6-31G(d) levels. Contributions from hindered rotors of S{sub 298}{degree} and Cp(T) are calculated by the method of Pitzer and Gwinn and by summation over the energy levels obtained by direct diagonalization of the Hamiltonian matrix of hindered internal rotations when the potential barriers of internal rotations are available. calculated rate constants obtained at CBS-q/MP2(full)/6-31G(d) and CBS-q//B3LYP/6-31G(d) levels of theory show similar trends with experimental data: HO{sub 2} radical

  15. Effect of sampling site and collection method on variations in baseline clinical pathology parameters in Fischer-344 rats. II. Clinical hematology.

    PubMed

    Smith, C N; Neptun, D A; Irons, R D

    1986-11-01

    An analysis of the influence of blood-sampling site and collection method on peripheral hematology parameters was conducted in age-matched male Fischer-344 rats. Sites examined for blood collection were the right ventricle, abdominal aorta, abdominal vena cava, retroorbital plexus, and tail. Collection methods used included syringe (10 ml), Vacutainer(s) (3 ml or 3 ml X 2), and capillary tube. Blood collected from the tail exhibited leukocyte counts approximately twice those of samples samples from other sites. Blood collected from the retroorbital plexus and tail exhibited significant variations in white blood cell count, red blood cell count, hemoglobin, and hematocrit, and differences in leukocyte differential counts of lymphocytes and neutrophils when compared with other sites. Blood collected from the abdominal aorta and in a second Vacutainer from the right ventricle exhibited lower erythrocyte, leukocyte, and platelet counts than that collected from other sites with the exception of the platelet count from tail blood which was lower than that from all other sites. Although parameter values vary with sample site selection, those obtained from right ventricle blood were the least variable and the most consistent when compared with all other methods. PMID:3803760

  16. Short Time Impulse Response Function (STIRF) for automatic evaluation of the variation of the dynamic parameters of reinforced concrete framed structures during strong earthquakes.

    NASA Astrophysics Data System (ADS)

    Carlo Ponzo, Felice; Ditommaso, Rocco

    2015-04-01

    This study presents an innovative strategy for automatic evaluation of the variable fundamental frequency and related damping factor of nonlinear structures during strong motion phases. Most of methods for damage detection are based on the assessment of the variations of the dynamic parameters characterizing the monitored structure. A crucial aspect of these methods is the automatic and accurate estimation of both structural eigen-frequencies and related damping factors also during the nonlinear behaviour. A new method, named STIRF (Short-Time Impulse Response Function - STIRF), based on the nonlinear interferometric analysis combined with the Fourier Transform (FT) here is proposed in order to allow scientists and engineers to characterize frequencies and damping variations of a monitored structure. The STIRF approach helps to overcome some limitation derived from the use of techniques based on simple Fourier Transform. These latter techniques provide good results when the response of the monitored system is stationary, but fails when the system exhibits a non-stationary, time-varying behaviour: even non-stationary input, soil-foundation and/or adjacent structures interaction phenomena can show the inadequacy of classic techniques to analysing the nonlinear and/or non-stationary behaviour of structures. In fact, using this kind of approach it is possible to improve some of the existing methods for the automatic damage detection providing stable results also during the strong motion phase. Results are consistent with those expected if compared with other techniques. The main advantage derived from the use of the proposed approach (STIRF) for Structural Health Monitoring is based on the simplicity of the interpretation of the nonlinear variations of the fundamental frequency and the related equivalent viscous damping factor. The proposed methodology has been tested on both numerical and experimental models also using data retrieved from shaking table tests. Based on

  17. Statistical kinetics for pulverized coal combustion

    SciTech Connect

    Hurt, R.H.; Lunden, M.M.; Brehob, E.G.; Maloney, D.J.

    1996-06-01

    Coal is a heterogeneous substance whose structure and properties are highly variable on the length scale of the particle sizes used in suspension-fired combustion systems. For certain applications the statistical variations among particles can play an important role. In this paper, three specialized, single-particle techniques are applied to quantify the variations in combustion reactivity and char particle density within pulverized char particle populations. Reactivity variations are investigated through captive particle imaging experiments and entrained flow reactor experiments employing single-particle optical diagnostics. Single-particle density variations are determined directly by a novel technique based on an electrodynamic microbalance equipped with an automated video imaging and image processing system. From these data, a coal-general statistical kinetic model is developed and validated against a large set of single-particle temperature measurements for ten coals of various rank burning in three different combustion environments. The model incorporates a single empirical parameter describing the heterogeneity in reactivity and can adequately describe the entire database using a single coal-independent value of this parameter. The use of the model is demonstrated in a series of numerical simulations of complete burnout process for size-classified and polydisperse fuel samples. The simulations show that incorporating statistical kinetics has an important effect on burnout predictions in certain cases, the importance increasing with decreases in temperature, mean reactivity, and breadth of the particle size distribution. 32 refs.

  18. Kinetics and Activation Parameters for Oxidations of Styrene by Compounds I from Cytochrome P450BM-3 (CYP102A1) Heme Domain and from CYP119†

    PubMed Central

    Yuan, Xinting; Wang, Qin; Horner, John H.; Sheng, Xin; Newcomb, Martin

    2009-01-01

    Cytochrome P450 (CYP or P450) enzymes are ubiquitous in nature where they catalyze a vast array of oxidation reactions. The active oxidants in P450s have long been assumed to be iron(IV)-oxo porphyrin radical cations termed Compounds I, but P450 Compounds I have proven difficult to prepare. The recent development of an entry to these transients by photo-oxidation of the corresponding iron(IV)-oxo neutral porphyrin species (Compounds II) permits spectroscopic and kinetic studies. We report here application of the photo-oxidation method for production of Compound I from the heme domain of CYP102A1 (cytochrome P450BM-3), and product and kinetic studies of reactions of styrene with this Compound I transient and also Compound I from CYP119. The studies were performed at low temperatures in 1:1 (v:v) mixtures of glycerol--phosphate buffer. Single turnover reactions at 0 °C gave styrene oxide in good yields. In kinetic studies conducted between −10 and −50 °C, both Compounds I displayed saturation kinetics permitting determinations of binding constants and first-order oxidation rate constants. Temperature-dependent functions for the binding constants and rate constants were determined for both Compounds I. In the temperature range studied, the Compound I transient from CYP102A1 heme domain bound styrene more strongly than Compound I from CYP119, but the rate constants for oxidations of styrene by the latter were somewhat larger than those for the former. The temperature dependent functions for the first-order oxidation reactions are log k = 13.2 – 15.2/2.303RT and log k = 13.3 – 14.6/2.303RT (kcal/mol) for Compounds I from CYP102A1 heme domain and CYP119, respectively. PMID:19708688

  19. Erbium hydride thermal desorption : controlling kinetics.

    SciTech Connect

    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.

  20. Kinetic description of metal nanocrystal oxidation: a combined theoretical and experimental approach for determining morphology and diffusion parameters in hollow nanoparticles by the nanoscale Kirkendall effect

    NASA Astrophysics Data System (ADS)

    Watanabe, Yoshiki; Mowbray, Ryan W.; Rice, Katherine P.; Stoykovich, Mark P.

    2014-10-01

    The oxidation of colloidal metal nanocrystals to form hollow shells via the nanoscale Kirkendall effect has been investigated using a combined theoretical and experimental approach. A generalized kinetic model for the formation of hollow nanoparticles describes the phenomenon and, unlike prior models, is applicable to any material system and accounts for the effect of surface energies. Phase diagrams of the ultimate oxidized nanoparticle morphology and the time to achieve complete oxidation are calculated, and are found to depend significantly upon consideration of surface energy effects that destabilize the initial formation of small voids. For the oxidation of Cu nanocrystals to Cu2O nanoparticles, we find that the diffusion coefficients dictate the morphological outcomes: the ratio of ? to ? controls the void size, ? determines the time of oxidation and ? is largely irrelevant in the kinetics of oxidation. The kinetic model was used to fit experimental measurements of 11 nm diameter Cu nanocrystals oxidized in air from which temperature-dependent diffusivities of ? and ? for 100 ≤ T ≤ 200 °C were determined. In contrast to previous interpretations of the nanoscale Kirkendall effect in the Cu/Cu2O system, these results are obtained without any a priori assumptions about the relative magnitudes of ? and ?. The theoretical and experimental approaches presented here are broadly applicable to any nanoparticle system undergoing oxidation, and can be used to precisely control the final nanoparticle morphology for applications in catalysis or optical materials.