Estimating equivalence with quantile regression
Cade, B.S.
2011-01-01
Equivalence testing and corresponding confidence interval estimates are used to provide more enlightened statistical statements about parameter estimates by relating them to intervals of effect sizes deemed to be of scientific or practical importance rather than just to an effect size of zero. Equivalence tests and confidence interval estimates are based on a null hypothesis that a parameter estimate is either outside (inequivalence hypothesis) or inside (equivalence hypothesis) an equivalence region, depending on the question of interest and assignment of risk. The former approach, often referred to as bioequivalence testing, is often used in regulatory settings because it reverses the burden of proof compared to a standard test of significance, following a precautionary principle for environmental protection. Unfortunately, many applications of equivalence testing focus on establishing average equivalence by estimating differences in means of distributions that do not have homogeneous variances. I discuss how to compare equivalence across quantiles of distributions using confidence intervals on quantile regression estimates that detect differences in heterogeneous distributions missed by focusing on means. I used one-tailed confidence intervals based on inequivalence hypotheses in a two-group treatment-control design for estimating bioequivalence of arsenic concentrations in soils at an old ammunition testing site and bioequivalence of vegetation biomass at a reclaimed mining site. Two-tailed confidence intervals based both on inequivalence and equivalence hypotheses were used to examine quantile equivalence for negligible trends over time for a continuous exponential model of amphibian abundance. ?? 2011 by the Ecological Society of America.
Estimating Equilibrium Effects of Job Search Assistance
DEFF Research Database (Denmark)
Gautier, Pieter; Muller, Paul; van der Klaauw, Bas
that the nonparticipants in the experiment regions find jobs slower after the introduction of the activation program (relative to workers in other regions). We then estimate an equilibrium search model. This model shows that a large scale role out of the activation program decreases welfare, while a standard partial...... microeconometric cost-benefit analysis would conclude the opposite....
Decentralized Pricing and the equivalence between Nash and Walrasian equilibrium
Mandel, Antoine; Gintis, Herbert
2016-01-01
International audience; We introduce, in the standard exchange economy model, market games in which agents use private prices as strategies. We give conditions on the game form that ensure that the only strict Nash equilibria of the game are the competitive equilibria of the underlying economy. This equivalence result has two main corollaries. First, it adds to the evidence that competitive equilibria can be strategically stable even in small economies. Second, it implies that competitive equ...
Estimation of U.S. Timber Harvest Using Roundwood Equivalents
James Howard
2006-01-01
This report details the procedure used to estimate the roundwood products portion of U.S. annual timber harvest levels by using roundwood equivalents. National-level U.S. forest products data published by trade associations and State and Federal Government organizations were used to estimate the roundwood equivalent of national roundwood products production. The...
Parameter Estimation for a Computable General Equilibrium Model
DEFF Research Database (Denmark)
Arndt, Channing; Robinson, Sherman; Tarp, Finn
We introduce a maximum entropy approach to parameter estimation for computable general equilibrium (CGE) models. The approach applies information theory to estimating a system of nonlinear simultaneous equations. It has a number of advantages. First, it imposes all general equilibrium constraints...
Parameter Estimation for a Computable General Equilibrium Model
DEFF Research Database (Denmark)
Arndt, Channing; Robinson, Sherman; Tarp, Finn
2002-01-01
We introduce a maximum entropy approach to parameter estimation for computable general equilibrium (CGE) models. The approach applies information theory to estimating a system of non-linear simultaneous equations. It has a number of advantages. First, it imposes all general equilibrium constraints...
Estimating Dynamic Equilibrium Models using Macro and Financial Data
DEFF Research Database (Denmark)
Christensen, Bent Jesper; Posch, Olaf; van der Wel, Michel
We show that including financial market data at daily frequency, along with macro series at standard lower frequency, facilitates statistical inference on structural parameters in dynamic equilibrium models. Our continuous-time formulation conveniently accounts for the difference in observation...... of the estimators and estimate the model using 20 years of U.S. macro and financial data....
Neural Net Gains Estimation Based on an Equivalent Model
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Karen Alicia Aguilar Cruz
2016-01-01
Full Text Available A model of an Equivalent Artificial Neural Net (EANN describes the gains set, viewed as parameters in a layer, and this consideration is a reproducible process, applicable to a neuron in a neural net (NN. The EANN helps to estimate the NN gains or parameters, so we propose two methods to determine them. The first considers a fuzzy inference combined with the traditional Kalman filter, obtaining the equivalent model and estimating in a fuzzy sense the gains matrix A and the proper gain K into the traditional filter identification. The second develops a direct estimation in state space, describing an EANN using the expected value and the recursive description of the gains estimation. Finally, a comparison of both descriptions is performed; highlighting the analytical method describes the neural net coefficients in a direct form, whereas the other technique requires selecting into the Knowledge Base (KB the factors based on the functional error and the reference signal built with the past information of the system.
Spatial estimates of snow water equivalent in the Sierra Nevada
Rittger, Karl Eric
The spatial distribution of snow and its melt over large river basins cannot be directly observed, complicating decisions for competing priorities of flood protection and resource use. This work aims to advance our ability to estimate snow distribution through improvements in the satellite observation of snow-covered area (SCA) and the modeling of snow water equivalent (SWE). I analyze the accuracies of three methods to map SCA from MODIS, a binary and a fractional method (MOD10A1) based on the normalized difference snow index (NDSI), and another fractional method based on spectral mixture analyses, MODSCAG. I find that fractional SCA estimates from MODSCAG perform best over a range of snow and vegetation conditions and the model maintains its retrieval ability in the transitional periods during accumulation and melt. Forest obstructs viewable snow cover, and satellite-viewing geometry has a larger effect on the fractional NDSI-based approach than MODSCAG. Adjustments to SCA to account for forest canopies permit MODSCAG to perform very well in all but the densest canopies while MOD10A1 shows early melt out, when compared with ground sensors, in sparse to moderately dense canopy. Combining satellite observed SCA and albedo with an energy balance model, I estimate spatially distributed snow water equivalent for 12 years in the Sierra Nevada. The model shows that the relationship of SWE with elevation is significantly different for wet, mean and dry years, between drainages and at different latitudes. SWE and SCA become increasingly correlated from March 1st to July 1st, such that real time SCA observations may be sufficient for SWE prediction. I compare spatially integrated volumes of snow water equivalent from this model and two real-time models with full natural flow estimates in 18 Sierra Nevada basins covering 70% of the streamflow range in the last 80 years. Forecasting errors that are based on statistical relationships between point measurements of snow and
Strength Estimation of Die Cast Beams Considering Equivalent Porous Defects
Energy Technology Data Exchange (ETDEWEB)
Park, Moon Shik [Hannam Univ., Daejeon (Korea, Republic of)
2017-05-15
As a shop practice, a strength estimation method for die cast parts is suggested, in which various defects such as pores can be allowed. The equivalent porosity is evaluated by combining the stiffness data from a simple elastic test at the part level during the shop practice and the theoretical stiffness data, which are defect free. A porosity equation is derived from Eshelby's inclusion theory. Then, using the Mori-Tanaka method, the porosity value is used to draw a stress-strain curve for the porous material. In this paper, the Hollomon equation is used to capture the strain hardening effect. This stress-strain curve can be used to estimate the strength of a die cast part with porous defects. An elastoplastic theoretical solution is derived for the three-point bending of a die cast beam by using the plastic hinge method as a reference solution for a part with porous defects.
Independent contrasts and PGLS regression estimators are equivalent.
Blomberg, Simon P; Lefevre, James G; Wells, Jessie A; Waterhouse, Mary
2012-05-01
We prove that the slope parameter of the ordinary least squares regression of phylogenetically independent contrasts (PICs) conducted through the origin is identical to the slope parameter of the method of generalized least squares (GLSs) regression under a Brownian motion model of evolution. This equivalence has several implications: 1. Understanding the structure of the linear model for GLS regression provides insight into when and why phylogeny is important in comparative studies. 2. The limitations of the PIC regression analysis are the same as the limitations of the GLS model. In particular, phylogenetic covariance applies only to the response variable in the regression and the explanatory variable should be regarded as fixed. Calculation of PICs for explanatory variables should be treated as a mathematical idiosyncrasy of the PIC regression algorithm. 3. Since the GLS estimator is the best linear unbiased estimator (BLUE), the slope parameter estimated using PICs is also BLUE. 4. If the slope is estimated using different branch lengths for the explanatory and response variables in the PIC algorithm, the estimator is no longer the BLUE, so this is not recommended. Finally, we discuss whether or not and how to accommodate phylogenetic covariance in regression analyses, particularly in relation to the problem of phylogenetic uncertainty. This discussion is from both frequentist and Bayesian perspectives.
Lucarini, Valerio; Gallavotti, Giovanni
We construct different equivalent non-equilibrium ensembles in the Lorenz '96 model of atmospheric turbulence. The vector field can be decomposed into an energy-conserving, time-reversible part, plus a non-time reversible part, including forcing and dissipation. We construct a modified version of the model where viscosity varies with time, so that energy is conserved, and the dynamics is time-reversible. The statistical properties of the irreversible and reversible model are in excellent agreement, if in the latter the energy is kept constant at a value equal to the time-average realized with the irreversible model. The average contraction rate of the phase space of the time-reversible model agrees with that of the irreversible model, where it is constant by construction. We show that the phase space contraction rate obeys the fluctuation relation, and we interpret its finite time corrections. A local version of the fluctuation relation is explored and successfully checked. The equivalence between the two ensembles extends to the Lyapunov exponents.These results have relevance in motivating the importance of the chaotic hypothesis. in explaining that we have the freedom to model non-equilibrium systems using different but equivalent approaches.
Towards Improved Snow Water Equivalent Estimation via GRACE Assimilation
Forman, Bart; Reichle, Rofl; Rodell, Matt
2011-01-01
Passive microwave (e.g. AMSR-E) and visible spectrum (e.g. MODIS) measurements of snow states have been used in conjunction with land surface models to better characterize snow pack states, most notably snow water equivalent (SWE). However, both types of measurements have limitations. AMSR-E, for example, suffers a loss of information in deep/wet snow packs. Similarly, MODIS suffers a loss of temporal correlation information beyond the initial accumulation and final ablation phases of the snow season. Gravimetric measurements, on the other hand, do not suffer from these limitations. In this study, gravimetric measurements from the Gravity Recovery and Climate Experiment (GRACE) mission are used in a land surface model data assimilation (DA) framework to better characterize SWE in the Mackenzie River basin located in northern Canada. Comparisons are made against independent, ground-based SWE observations, state-of-the-art modeled SWE estimates, and independent, ground-based river discharge observations. Preliminary results suggest improved SWE estimates, including improved timing of the subsequent ablation and runoff of the snow pack. Additionally, use of the DA procedure can add vertical and horizontal resolution to the coarse-scale GRACE measurements as well as effectively downscale the measurements in time. Such findings offer the potential for better understanding of the hydrologic cycle in snow-dominated basins located in remote regions of the globe where ground-based observation collection if difficult, if not impossible. This information could ultimately lead to improved freshwater resource management in communities dependent on snow melt as well as a reduction in the uncertainty of river discharge into the Arctic Ocean.
Snow Water Equivalent estimation based on satellite observation
Macchiavello, G.; Pesce, F.; Boni, G.; Gabellani, S.
2009-09-01
The availability of remotely sensed images and them analysis is a powerful tool for monitoring the extension and typology of snow cover over territory where the in situ measurements are often difficult. Information on snow are fundamental for monitoring and forecasting the available water above all in regions at mid latitudes as Mediterranean where snowmelt may cause floods. The hydrological model requirements and the daily acquisitions of MODIS (Moderate Resolution Imaging Spectroradiometer), drove, in previous research activities, to the development of a method to automatically map the snow cover from multi-spectral images. But, the major hydrological parameter related to the snow pack is the Snow Water Equivalent (SWE). This represents a direct measure of stored water in the basin. Because of it, the work was focused to the daily estimation of SWE from MODIS images. But, the complexity of this aim, based only on optical data, doesn’t find any information in literature. Since, from the spectral range of MODIS data it is not possible to extract a direct relation between spectral information and the SWE. Then a new method, respectful of the physic of the snow, was defined and developed. Reminding that the snow water equivalent is the product of the three factors as snow density, snow depth and the snow covered areas, the proposed approach works separately on each of these physical behaviors. Referring to the physical characteristic of snow, the snow density is function of the snow age, then it was studied a new method to evaluate this. Where, a module for snow age simulation from albedo information was developed. It activates an age counter updated by new snow information set to estimate snow age from zero accumulation status to the end of melting season. The height of the snow pack, can be retrieved by adopting relation between vegetation and snow depth distributions. This computes snow height distribution by the relation between snow cover fraction and the
Verrel, Julius; Lövdén, Martin; Lindenberger, Ulman
2012-01-01
Stable walking depends on the coordination of multiple biomechanical degrees of freedom to ensure the dynamic maintenance of whole-body equilibrium as well as continuous forward progression. We investigated adult age-related differences in whole-body coordination underlying stabilization of center of mass (CoM) position and step pattern during locomotion. Sixteen younger (20-30 years) and 16 healthy older men (65–80 years) walked on a motorized treadmill at 80%, 100% and 120% of their self-selected preferred speed. Preferred speeds did not differ between the age groups. Motor-equivalent stabilization of step parameters (step length and width) and CoM position relative to the support (back and front foot) was examined using a generalized covariation analysis. Across age groups, covariation indices were highest for CoM position relative to the front foot, the measure most directly related to body equilibrium. Compared to younger adults, older adults showed lower covariation indices with respect to step length, extending previous findings of age-related differences in motor-equivalent coordination. In contrast, no reliable age differences were found regarding stabilization of step width or any of the CoM parameters. The observed pattern of results may reflect robust prioritization of balance over step pattern regularity, which may be adaptive in the face of age-associated sensorimotor losses and decline of coordinative capacities. PMID:23272200
Data-Driven Method to Estimate Nonlinear Chemical Equivalence.
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Michael Mayo
Full Text Available There is great need to express the impacts of chemicals found in the environment in terms of effects from alternative chemicals of interest. Methods currently employed in fields such as life-cycle assessment, risk assessment, mixtures toxicology, and pharmacology rely mostly on heuristic arguments to justify the use of linear relationships in the construction of "equivalency factors," which aim to model these concentration-concentration correlations. However, the use of linear models, even at low concentrations, oversimplifies the nonlinear nature of the concentration-response curve, therefore introducing error into calculations involving these factors. We address this problem by reporting a method to determine a concentration-concentration relationship between two chemicals based on the full extent of experimentally derived concentration-response curves. Although this method can be easily generalized, we develop and illustrate it from the perspective of toxicology, in which we provide equations relating the sigmoid and non-monotone, or "biphasic," responses typical of the field. The resulting concentration-concentration relationships are manifestly nonlinear for nearly any chemical level, even at the very low concentrations common to environmental measurements. We demonstrate the method using real-world examples of toxicological data which may exhibit sigmoid and biphasic mortality curves. Finally, we use our models to calculate equivalency factors, and show that traditional results are recovered only when the concentration-response curves are "parallel," which has been noted before, but we make formal here by providing mathematical conditions on the validity of this approach.
Data-Driven Method to Estimate Nonlinear Chemical Equivalence.
Mayo, Michael; Collier, Zachary A; Winton, Corey; Chappell, Mark A
2015-01-01
There is great need to express the impacts of chemicals found in the environment in terms of effects from alternative chemicals of interest. Methods currently employed in fields such as life-cycle assessment, risk assessment, mixtures toxicology, and pharmacology rely mostly on heuristic arguments to justify the use of linear relationships in the construction of "equivalency factors," which aim to model these concentration-concentration correlations. However, the use of linear models, even at low concentrations, oversimplifies the nonlinear nature of the concentration-response curve, therefore introducing error into calculations involving these factors. We address this problem by reporting a method to determine a concentration-concentration relationship between two chemicals based on the full extent of experimentally derived concentration-response curves. Although this method can be easily generalized, we develop and illustrate it from the perspective of toxicology, in which we provide equations relating the sigmoid and non-monotone, or "biphasic," responses typical of the field. The resulting concentration-concentration relationships are manifestly nonlinear for nearly any chemical level, even at the very low concentrations common to environmental measurements. We demonstrate the method using real-world examples of toxicological data which may exhibit sigmoid and biphasic mortality curves. Finally, we use our models to calculate equivalency factors, and show that traditional results are recovered only when the concentration-response curves are "parallel," which has been noted before, but we make formal here by providing mathematical conditions on the validity of this approach.
Directory of Open Access Journals (Sweden)
Milad Haghani
2016-06-01
Further investigations with respect to the relative importance of STA model estimation (or equivalently, parameter calibration and model specification (or equivalently, error term formulation are also conducted. A paired combinatorial logit (PCL assignment model with an origin–destination-specific-parameter, along with a heuristic method of model estimation (calibration, is proposed. The proposed model cannot only accommodate the correlation between path utilities, but also accounts for the fact that travelling between different origin–destination (O–D pairs can correspond to different levels of stochasticity and choice randomness. Results suggest that the estimation of the stochastic user equilibrium (SUE models can affect the outcome of the flow prediction far more meaningfully than the complexity of the choice model (i.e., model specification.
National Research Council Canada - National Science Library
Jauhari Dahalan; Mohammed Umar; Hussin Abdullah
2016-01-01
.... Based on the suggestion of the weak exogeneity and unit vector analysis, the study estimates the equilibrium and sustainable equilibrium real exchange rate based on the behavioural equilibrium exchange rate (BEER...
Estimation of Paddy Equilibrium Moisture Sorption Using ANNs
Amiri Chayjan, R.; Moazez, Y.
In this research, Artificial Neural Networks (ANNs) used for prediction of Equilibrium Moisture Content (EMC) of three varieties of paddy (Sadri, Tarom and Khazar) as a new method. Feed forward back propagation and cascade forward back propagation networks with Levenberg-Marquardt and Bayesian regularization training algorithms used for training of input patterns. Optimized trained network has the ability of EMC prediction to test patterns at thermal boundary of 20-40°C and relative humidity boundary of 13.5-87% with R2 = 0.9929 and mean absolute error 0.0229. Comparison between optimized ANN result and empirical model of Henderson showed that artificial neural network not only can simultaneously predict the EMC of samples of all varieties but also has better coefficient of determination and less mean absolute error.
Estimation of the initial equilibrium constants in the formation of tetragonal lysozyme nuclei
Pusey, Marc L.
1991-01-01
Results are presented from a study of the equilibria, kinetic rates, and the aggregation pathway which leads from a lysozyme monomer crystal to a tetragonal crystal, using dialyzed and recrystallized commercial hen eggwhite lysozyme. Relative light scattering intensity measurements were used to estimate the initial equilibrium constants for undersaturated lysozyme solutions in the tetragonal regime. The K1 value was estimated to be (1-3) x 10 exp 4 L/mol. Estimates of subsequent equilibrium constants depend on the crystal aggregation model chosen or determined. Experimental data suggest that tetragonal lysozyme crystal grows by addition of aggregates preformed in the bulk solution, rather than by monomer addition.
Variance estimation of allele-based odds ratio in the absence of Hardy-Weinberg equilibrium.
Zintzaras, Elias
2008-01-01
In gene-disease association studies, deviation from Hardy-Weinberg equilibrium in controls may cause bias in estimating the allele-based estimates of genetic effects. An approach to adjust the variance of allele-based odds ratio for Hardy-Weinberg equilibrium deviation is proposed. Such adjustments have been introduced for estimating relative risks of genotype contrasts and differences in allele frequency; however, an adjustment of odds ratios for allele frequencies still does not exist. The approach was based on the delta method in combination with the Woolf's logit interval method and the disequilibrium coefficient. The proposed variance adjustment provided better power than the unadjusted one to detect significant estimates of odds ratio and it improved the variance estimation.
An improved method to estimate the equivalent circuit parameters in DSSCs
Energy Technology Data Exchange (ETDEWEB)
Hanmin, Tian; Xiaobo, Zhang; Shikui, Yuan; Xiangyan, Wang; Zhipeng, Tian; Bin, Liu [Department of Materials Science and Engineering, Nanjing University, Nanjing 210093 (China); Ying, Wang [Eco-Materials and Renewable Energy Research Center (ERERC), Department of Physics, Nanjing University, 22 Hankou Road, Nanjing 210093 (China); Tao, Yu; Zhigang, Zou [National Laboratory of Solid State Microstructures, Nanjing 210093 (China)
2009-05-15
In this report, an improved method to estimate the equivalent circuit parameters in the dye-sensitized solar cells (DSSCs) is introduced. It is founded that, several different groups of values of equivalent circuit parameters can fit well to the same experiment-measured I-V curve. Furthermore, the gap between some parameter values in those different groups is so large that it reaches up to several orders of magnitude. To eliminate this uncertainty of parameter estimation, an improved method, which based on both the extention of measured range and the computer simulation of current-voltage (I-V) characteristic curves, is proposed to ensure uniquely the values of DSSCs equivalent circuit parameters. A series of I-V curves which derived from the estimated parameters by this improved method fit well to the corresponding experiment-measured I-V curves. The results indicate that, there exclusively exists one group of parameter values for a special DSSCs equivalent circuit, thus demonstrating the validity of the improved method proposed in this work. (author)
Nakazawa, Shoji; Maeda, Haruki
2017-10-01
The purpose of this paper is to propose a simply evaluation method for a dynamic ductility index dF and a seismic performance index dIs by using the equivalent linearization method. These indices dF and dIs indicate the ductility and seismic performance of the structure corresponding to the critical deformation of members, and are evaluated based on the nonlinear seismic response analysis. Therefore, in this study, the estimation method of dF and dIs using the equivalent linearization method are proposed. By comparing between the value of dF calculated by the nonlinear analysis of a single degree of freedom system and the value of dFest obtained by the proposed estimation method, the validity of the proposed estimation method is discussed.
Directory of Open Access Journals (Sweden)
Leszek Klukowski
2012-01-01
Full Text Available This paper presents a review of results of the author in the area of estimation of the relations of equivalence, tolerance and preference within a finite set based on multiple, independent (in a stochastic way pairwise comparisons with random errors, in binary and multivalent forms. These estimators require weaker assumptions than those used in the literature on the subject. Estimates of the relations are obtained based on solutions to problems from discrete optimization. They allow application of both types of comparisons - binary and multivalent (this fact relates to the tolerance and preference relations. The estimates can be verified in a statistical way; in particular, it is possible to verify the type of the relation. The estimates have been applied by the author to problems regarding forecasting, financial engineering and bio-cybernetics. (original abstract
Applicability of OSL pre-dose phenomenon of quartz in the estimation of equivalent dose
Energy Technology Data Exchange (ETDEWEB)
Koul, D.K., E-mail: dkkoul@barc.gov.i [Astrophysical Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Chougaonkar, M.P. [Environmental Assessment Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Polymeris, G.S. [Archaeometry Laboratory, Cultural and Educational Technology Institute, R.C. ' Athena' , Tsimiski 58, GR-67100, Xanthi (Greece)
2010-01-15
The feasibility of utilizing the pre-dosed OSL signal in the estimation of the equivalent dose has been investigated. The results based on (i) the behavior of growth curve, (ii) dose recovery tests and (iii) non-bleachability of reservoir centres, R-centres, suggests that (i) the pre-dosed OSL does not seem to work satisfactorily in dose estimation unlike the pre-dosed 110 deg. C TL emission and (ii) it may not be applicable in case of bleached specimen.
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Antonia S. J. S. Mey
2014-10-01
Full Text Available Computing the equilibrium properties of complex systems, such as free energy differences, is often hampered by rare events in the dynamics. Enhanced sampling methods may be used in order to speed up sampling by, for example, using high temperatures, as in parallel tempering, or simulating with a biasing potential such as in the case of umbrella sampling. The equilibrium properties of the thermodynamic state of interest (e.g., lowest temperature or unbiased potential can be computed using reweighting estimators such as the weighted histogram analysis method or the multistate Bennett acceptance ratio (MBAR. weighted histogram analysis method and MBAR produce unbiased estimates, the simulation samples from the global equilibria at their respective thermodynamic states—a requirement that can be prohibitively expensive for some simulations such as a large parallel tempering ensemble of an explicitly solvated biomolecule. Here, we introduce the transition-based reweighting analysis method (TRAM—a class of estimators that exploit ideas from Markov modeling and only require the simulation data to be in local equilibrium within subsets of the configuration space. We formulate the expanded TRAM (xTRAM estimator that is shown to be asymptotically unbiased and a generalization of MBAR. Using four exemplary systems of varying complexity, we demonstrate the improved convergence (ranging from a twofold improvement to several orders of magnitude of xTRAM in comparison to a direct counting estimator and MBAR, with respect to the invested simulation effort. Lastly, we introduce a random-swapping simulation protocol that can be used with xTRAM, gaining orders-of-magnitude advantages over simulation protocols that require the constraint of sampling from a global equilibrium.
On the equivalence of Kalman filtering and least-squares estimation
Mysen, E.
2017-01-01
The Kalman filter is derived directly from the least-squares estimator, and generalized to accommodate stochastic processes with time variable memory. To complete the link between least-squares estimation and Kalman filtering of first-order Markov processes, a recursive algorithm is presented for the computation of the off-diagonal elements of the a posteriori least-squares error covariance. As a result of the algebraic equivalence of the two estimators, both approaches can fully benefit from the advantages implied by their individual perspectives. In particular, it is shown how Kalman filter solutions can be integrated into the normal equation formalism that is used for intra- and inter-technique combination of space geodetic data.
Soil moisture storage estimation based on steady vertical fluxes under equilibrium
Amvrosiadi, Nino; Bishop, Kevin; Seibert, Jan
2017-10-01
Soil moisture is an important variable for hillslope and catchment hydrology. There are various computational methods to estimate soil moisture and their complexity varies greatly: from one box with vertically constant volumetric soil water content to fully saturated-unsaturated coupled physically-based models. Different complexity levels are applicable depending on the simulation scale, computational time limitations, input data and knowledge about the parameters. The Vertical Equilibrium Model (VEM) is a simple approach to estimate the catchment-wide soil water storage at a daily time-scale on the basis of water table level observations, soil properties and an assumption of hydrological equilibrium without vertical fluxes above the water table. In this study VEM was extended by considering vertical fluxes, which allows conditions with evaporation and infiltration to be represented. The aim was to test the hypothesis that the simulated volumetric soil water content significantly depends on vertical fluxes. The water content difference between the no-flux, equilibrium approach and the new constant-flux approach greatly depended on the soil textural class, ranging between ∼1% for silty clay and ∼44% for sand at an evapotranspiration rate of 5 mm·d-1. The two approaches gave a mean volumetric soil water content difference of ∼1 mm for two case studies (sandy loam and organic rich soils). The results showed that for many soil types the differences in estimated storage between the no-flux and the constant flux approaches were relatively small.
Estimates of internal-dose equivalent from inhalation and ingestion of selected radionuclides
Energy Technology Data Exchange (ETDEWEB)
Dunning, D.E.
1982-01-01
This report presents internal radiation dose conversion factors for radionuclides of interest in environmental assessments of nuclear fuel cycles. This volume provides an updated summary of estimates of committed dose equivalent for radionuclides considered in three previous Oak Ridge National Laboratory (ORNL) reports. Intakes by inhalation and ingestion are considered. The International Commission on Radiological Protection (ICRP) Task Group Lung Model has been used to simulate the deposition and retention of particulate matter in the respiratory tract. Results corresponding to activity median aerodynamic diameters (AMAD) of 0.3, 1.0, and 5.0 ..mu..m are given. The gastorintestinal (GI) tract has been represented by a four-segment catenary model with exponential transfer of radioactivity from one segment to the next. Retention of radionuclides in systemic organs is characterized by linear combinations of decaying exponential functions, recommended in ICRP Publication 30. The first-year annual dose rate, maximum annual dose rate, and fifty-year dose commitment per microcurie intake of each radionuclide is given for selected target organs and the effective dose equivalent. These estimates include contributions from specified source organs plus the systemic activity residing in the rest of the body; cross irradiation due to penetrating radiations has been incorporated into these estimates. 15 references.
The performance of simulated annealing in parameter estimation for vapor-liquid equilibrium modeling
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A. Bonilla-Petriciolet
2007-03-01
Full Text Available In this paper we report the application and evaluation of the simulated annealing (SA optimization method in parameter estimation for vapor-liquid equilibrium (VLE modeling. We tested this optimization method using the classical least squares and error-in-variable approaches. The reliability and efficiency of the data-fitting procedure are also considered using different values for algorithm parameters of the SA method. Our results indicate that this method, when properly implemented, is a robust procedure for nonlinear parameter estimation in thermodynamic models. However, in difficult problems it still can converge to local optimums of the objective function.
Estimation of the equilibrium formation temperature in the presence of bore fluid invasion
DEFF Research Database (Denmark)
Poulsen, Søren Erbs; Nielsen, S.B.; Balling, N.
2012-01-01
Bottom hole temperatures (BHTs) measured during drilling operations are thermally disturbed by the drilling process. This paper presents a method, CSMI (Cylindrical Source Model with Invasion of bore mud filtrate), for estimating equilibrium formation temperatures with probability distributions...... from BHT measurements in the presence of bore fluid invasion. The scheme is based on finite element analysis in conjunction with Markov chain Monte Carlo inversion. The axisymmetric forward model assumes a cylindrical source of finite radius and contrasting thermal parameters, which includes...... the possibility of invasion (advection) of mud filtrate into the formation. In a synthetic example, it is demonstrated that given bore fluid invasion and a low and high temperature of the bore mud and formation, respectively, the equilibrium formation temperature and the uncertainty hereon is underestimated...
Dozier, J.; Bair, N.; Calfa, A. A.; Skalka, C.; Tolle, K.; Bongard, J.
2015-12-01
The task is to estimate spatiotemporally distributed estimates of snow water equivalent (SWE) in snow-dominated mountain environments, including those that lack on-the-ground measurements such as the Hindu Kush range in Afghanistan. During the snow season, we can use two measurements: (1) passive microwave estimates of SWE, which generally underestimate in the mountains; (2) fractional snow-covered area from MODIS. Once the snow has melted, we can reconstruct the accumulated SWE back to the last significant snowfall by calculating the energy used in melt. The reconstructed SWE values provide a training set for predictions from the passive microwave SWE and snow-covered area. We examine several machine learning methods—regression-boosted decision trees, bagged trees, neural networks, and genetic programming—to estimate SWE. All methods work reasonably well, with R2 values greater than 0.8. Predictors built with multiple years of data reduce the bias that usually appears if we predict one year from just one other year's training set. Genetic programming tends to produce results that additionally provide physical insight. Adding precipitation estimates from the Global Precipitation Measurements mission is in progress.
Li, Dongyue; Durand, Michael; Margulis, Steven A.
2017-01-01
This paper demonstrates improved retrieval of snow water equivalent (SWE) from spaceborne passive microwave measurements for the sparsely forested Upper Kern watershed (511 km2) in the southern Sierra Nevada (USA). This is accomplished by assimilating AMSR-E 36.5 GHz measurements into model predictions of SWE at 90 m spatial resolution using the Ensemble Batch Smoother (EnBS) data assimilation framework. For each water year (WY) from 2003 to 2008, SWE was estimated for the accumulation season (1 October to 1 April) with the assimilation of the measurements in the dry snow season (1 December to 28 February). The EnBS SWE estimation was validated against snow courses and snow pillows. On average, the EnBS accumulation season SWE RMSE was 77.4 mm (13.1%, relative to peak accumulation), despite deep snow (average peak SWE of 545 mm). The prior model estimate without assimilation had an accumulation season average RMSE of 119.7 mm. After assimilation, the overall bias of the accumulation season SWE estimates was reduced by 84.2%, and the RMSE reduced by 35.4%. The assimilation also reduced the bias and the RMSE of the 1 April SWE estimates by 80.9% and 45.4%, respectively. The EnBS is expected to work well above tree line and for dry snow.
A new online detector for estimation of peripheral neutron equivalent dose in organ
Energy Technology Data Exchange (ETDEWEB)
Irazola, L., E-mail: leticia@us.es; Sanchez-Doblado, F. [Departamento de Fisiología Médica y Biofísica, Universidad de Sevilla, Sevilla 41009, Spain and Servicio de Radiofísica, Hospital Universitario Virgen Macarena, Sevilla 41007 (Spain); Lorenzoli, M.; Pola, A. [Departimento di Ingegneria Nuclear, Politecnico di Milano, Milano 20133 (Italy); Bedogni, R. [Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare (INFN), Frascati Roma 00044 (Italy); Terrón, J. A. [Servicio de Radiofísica, Hospital Universitario Virgen Macarena, Sevilla 41007 (Spain); Sanchez-Nieto, B. [Instituto de Física, Pontificia Universidad Católica de Chile, Santiago 4880 (Chile); Expósito, M. R. [Departamento de Física, Universitat Autònoma de Barcelona, Bellaterra 08193 (Spain); Lagares, J. I.; Sansaloni, F. [Centro de Investigaciones Energéticas y Medioambientales y Tecnológicas (CIEMAT), Madrid 28040 (Spain)
2014-11-01
Purpose: Peripheral dose in radiotherapy treatments represents a potential source of secondary neoplasic processes. As in the last few years, there has been a fast-growing concern on neutron collateral effects, this work focuses on this component. A previous established methodology to estimate peripheral neutron equivalent doses relied on passive (TLD, CR39) neutron detectors exposed in-phantom, in parallel to an active [static random access memory (SRAMnd)] thermal neutron detector exposed ex-phantom. A newly miniaturized, quick, and reliable active thermal neutron detector (TNRD, Thermal Neutron Rate Detector) was validated for both procedures. This first miniaturized active system eliminates the long postprocessing, required for passive detectors, giving thermal neutron fluences in real time. Methods: To validate TNRD for the established methodology, intrinsic characteristics, characterization of 4 facilities [to correlate monitor value (MU) with risk], and a cohort of 200 real patients (for second cancer risk estimates) were evaluated and compared with the well-established SRAMnd device. Finally, TNRD was compared to TLD pairs for 3 generic radiotherapy treatments through 16 strategic points inside an anthropomorphic phantom. Results: The performed tests indicate similar linear dependence with dose for both detectors, TNRD and SRAMnd, while a slightly better reproducibility has been obtained for TNRD (1.7% vs 2.2%). Risk estimates when delivering 1000 MU are in good agreement between both detectors (mean deviation of TNRD measurements with respect to the ones of SRAMnd is 0.07 cases per 1000, with differences always smaller than 0.08 cases per 1000). As far as the in-phantom measurements are concerned, a mean deviation smaller than 1.7% was obtained. Conclusions: The results obtained indicate that direct evaluation of equivalent dose estimation in organs, both in phantom and patients, is perfectly feasible with this new detector. This will open the door to an
Chen, Y.; Liu, X.; Manko ff, K. D.; Gulley, J. D.
2016-12-01
The surfaces of subglacial conduits are very complex, coupling multi-scale roughness, large sinuosity, and cross-sectional variations together. Those features significantly affect the friction law and drainage efficiency inside the conduit by altering velocity and pressure distributions, thus posing considerable influences on the dynamic development of the conduit. Parameterizing the above surface features is a first step towards understanding their hydraulic influences. A Matlab package is developed to extract the roughness field, the conduit centerline, and associated area and curvature data from the conduit surface, acquired from 3D scanning. By using those data, the characteristic vertical and horizontal roughness scales are then estimated based on the structure functions. The centerline sinuosities, defined through three concepts, i.e., the traditional definition of a fluvial river, entropy-based sinuosity, and curvature-based sinuosity, are also calculated and compared. The cross-sectional area and equivalent circular diameter along the centerline are also calculated. Among those features, the roughness is especially important due to its pivotal role in determining the wall friction, and thus an estimation of the equivalent roughness height is of great importance. To achieve such a goal, the original conduit is firstly simplified into a straight smooth pipe with the same volume and centerline length, and the roughness field obtained above is then reconstructed into the simplified pipe. An OpenFOAM-based Large-eddy-simulation (LES) is then performed based on the reconstructed pipe. Considering that the Reynolds number is of the order 106, and the relative roughness is larger than 5% for 60% of the conduit, we test the validity of the resistance law for completely rough pipe. The friction factor is calculated based on the pressure drop and mean velocity in the simulation. Working together, the equivalent roughness height can be calculated. However, whether the
Using geostatistical methods to estimate snow water equivalence distribution in a mountain watershed
Balk, B.; Elder, K.; Baron, Jill S.
1998-01-01
Knowledge of the spatial distribution of snow water equivalence (SWE) is necessary to adequately forecast the volume and timing of snowmelt runoff. In April 1997, peak accumulation snow depth and density measurements were independently taken in the Loch Vale watershed (6.6 km2), Rocky Mountain National Park, Colorado. Geostatistics and classical statistics were used to estimate SWE distribution across the watershed. Snow depths were spatially distributed across the watershed through kriging interpolation methods which provide unbiased estimates that have minimum variances. Snow densities were spatially modeled through regression analysis. Combining the modeled depth and density with snow-covered area (SCA produced an estimate of the spatial distribution of SWE. The kriged estimates of snow depth explained 37-68% of the observed variance in the measured depths. Steep slopes, variably strong winds, and complex energy balance in the watershed contribute to a large degree of heterogeneity in snow depth.
Inductive machine learning for improved estimation of catchment-scale snow water equivalent
Buckingham, David; Skalka, Christian; Bongard, Josh
2015-05-01
Infrastructure for the automatic collection of single-point measurements of snow water equivalent (SWE) is well-established. However, because SWE varies significantly over space, the estimation of SWE at the catchment scale based on a single-point measurement is error-prone. We propose low-cost, lightweight methods for near-real-time estimation of mean catchment-wide SWE using existing infrastructure, wireless sensor networks, and machine learning algorithms. Because snowpack distribution is highly nonlinear, we focus on Genetic Programming (GP), a nonlinear, white-box, inductive machine learning algorithm. Because we did not have access to near-real-time catchment-scale SWE data, we used available data as ground truth for machine learning in a set of experiments that are successive approximations of our goal of catchment-wide SWE estimation. First, we used a history of maritime snowpack data collected by manual snow courses. Second, we used distributed snow depth (HS) data collected automatically by wireless sensor networks. We compared the performance of GP against linear regression (LR), binary regression trees (BT), and a widely used basic method (BM) that naively assumes non-variable snowpack. In the first experiment set, GP and LR models predicted SWE with lower error than BM. In the second experiment set, GP had lower error than LR, but outperformed BT only when we applied a technique that specifically mitigated the possibility of over-fitting.
Estimating time and spatial distribution of snow water equivalent in the Hakusan area
Tanaka, K.; Matsui, Y.; Touge, Y.
2015-12-01
In the Sousei program, on-going Japanese research program for risk information on climate change, assessing the impact of climate change on water resources is attempted using the integrated water resources model which consists of land surface model, irrigation model, river routing model, reservoir operation model, and crop growth model. Due to climate change, reduction of snowfall amount, reduction of snow cover and change in snowmelt timing, change in river discharge are of increasing concern. So, the evaluation of snow water amount is crucial for assessing the impact of climate change on water resources in Japan. To validate the snow simulation of the land surface model, time and spatial distribution of the snow water equivalent was estimated using the observed surface meteorological data and RAP (Radar Analysis Precipitation) data. Target area is Hakusan. Hakusan means 'white mountain' in Japanese. Water balance of the Tedori River Dam catchment was checked with daily inflow data. Analyzed runoff was generally well for the period from 2010 to 2012. From the result for 2010-2011 winter, maximum snow water equivalent in the headwater area of the Tedori River dam reached more than 2000mm in early April. On the other hand, due to the underestimation of RAP data, analyzed runoff was under estimated from 2006 to 2009. This underestimation is probably not from the lack of land surface model, but from the quality of input precipitation data. In the original RAP, only the rain gauge data of JMA (Japan Meteorological Agency) were used in the analysis. Recently, other rain gauge data of MLIT (Ministry of Land, Infrastructure, Transport and Tourism) and local government have been added in the analysis. So, the quality of the RAP data especially in the mountain region has been greatly improved. "Reanalysis" of the RAP precipitation is strongly recommended using all the available off-line rain gauges information. High quality precipitation data will contribute to validate
Kuk, Anthony Y C; Zhang, Han; Yang, Yaning
2009-02-01
Pooling large number of DNA samples is a common practice in association study, especially for initial screening. However, the use of expectation-maximization (EM)-type algorithms in estimating haplotype distributions for even moderate pool sizes is hampered by the computational complexity involved. A novel constrained EM algorithm called PoooL has been proposed recently to bypass the difficulty via the use of asymptotic normality of the pooled allele frequencies. The resulting estimates are, however, not maximum likelihood estimates and hence not optimal. Furthermore, the assumption of Hardy-Weinberg equilibrium (HWE) made may not be realistic in practice. Rather than carrying out constrained maximization as in PoooL, we revert to the usual EM algorithm but make it computationally feasible by using normal approximations. The resulting algorithm is much simpler to implement than PoooL because there is no need to invoke sophisticated iterative scaling methods as in PoooL. We also develop an estimating equation analogue of the EM algorithm for the case of Hardy-Weinberg disequilibrium (HWD) by conditioning on the haplotypes of both chromosomes of the same individual. Incorporated into the method is a way of estimating the inbreeding coefficient by relating it to overdispersion. Simulation study assuming HWE shows that our simplified implementation of the EM algorithm leads to estimates with substantially smaller SDs than PoooL estimates. Further simulations show that ignoring HWD will induce biases in the estimates. Our extended method with estimation of inbreeding coefficient incorporated is able to reduce the bias leading to estimates with substantially smaller mean square errors. We also present results to suggest that our method can cope with a certain degree of locus-specific inbreeding as well as additional overdispersion not caused by inbreeding. http://staff.ustc.edu.cn/ approximately ynyang/aem-aes
Estimates of Regional Equilibrium Line Altitudes and Net Mass Balance from MODIS Imagery
Shea, J. M.; Menounos, B.; Moore, R. D.
2011-12-01
Glacier mass balance is a key variable used to assess the health of glaciers and ice sheets. Estimates of glacier mass balance are required to model the dynamic response of glaciers and ice sheets to climate change, estimate sea-level contribution from surface melt, and document the response of glaciers to climate forcing. Annually resolved estimates of regional mass balance for mountain ranges is often inferred from a sparse network of ground-based measurements of mass balance for individual glaciers. Given that net mass balance is highly correlated with the annual equilibrium line altitude (ELA), we develop an automated approach to estimate the ELA, and by inference net mass balance, on large glaciers and icefields using MODIS 250 m imagery (MOD02QKM). We discriminate areas of bare ice and snow/firn using the product of MODIS' red (0.620 - 0.670 μ m) and near infrared (0.841 - 0.876 μ m) bands. To assess the skill in estimating glacier ELAs, we compare ELAs derived from (1) manual delineation and (2) unsupervised classification of the band product to ground-based observations of ELA and net mass balance at seven long term mass-balance monitoring sites in western North America (Gulkana, Wolverine, Lemon Creek, Taku, Place, Peyto, and South Cascade). Spatial and temporal variations in MODIS-derived ELAs provide an opportunity to validate regional mass-balance models, estimate surface melt contributions to sea-level rise, and examine the cryospheric response to climate change.
Estimating Snow Water Equivalent with Backscattering at X and Ku Band Based on Absorption Loss
Directory of Open Access Journals (Sweden)
Yurong Cui
2016-06-01
Full Text Available Snow water equivalent (SWE is a key parameter in the Earth’s energy budget and water cycle. It has been demonstrated that SWE can be retrieved using active microwave remote sensing from space. This necessitates the development of forward models that are capable of simulating the interactions of microwaves and the snow medium. Several proposed models have described snow as a collection of sphere- or ellipsoid-shaped ice particles embedded in air, while the microstructure of snow is, in reality, more complex. Natural snow usually forms a sintered structure following mechanical and thermal metamorphism processes. In this research, the bi-continuous vector radiative transfer (bi-continuous-VRT model, which firstly constructs snow microstructure more similar to real snow and then simulates the snow backscattering signal, is used as the forward model for SWE estimation. Based on this forward model, a parameterization scheme of snow volume backscattering is proposed. A relationship between snow optical thickness and single scattering albedo at X and Ku bands is established by analyzing the database generated from the bi-continuous-VRT model. A cost function with constraints is used to solve effective albedo and optical thickness, while the absorption part of optical thickness is obtained from these two parameters. SWE is estimated after a correction for physical temperature. The estimated SWE is correlated with the measured SWE with an acceptable accuracy. Validation against two-year measurements, using the SnowScat instrument from the Nordic Snow Radar Experiment (NoSREx, shows that the estimated SWE using the presented algorithm has a root mean square error (RMSE of 16.59 mm for the winter of 2009–2010 and 19.70 mm for the winter of 2010–2011.
Dozier, J.; Tolle, K.; Bair, N.
2014-12-01
We have a problem that may be a specific example of a generic one. The task is to estimate spatiotemporally distributed estimates of snow water equivalent (SWE) in snow-dominated mountain environments, including those that lack on-the-ground measurements. Several independent methods exist, but all are problematic. The remotely sensed date of disappearance of snow from each pixel can be combined with a calculation of melt to reconstruct the accumulated SWE for each day back to the last significant snowfall. Comparison with streamflow measurements in mountain ranges where such data are available shows this method to be accurate, but the big disadvantage is that SWE can only be calculated retroactively after snow disappears, and even then only for areas with little accumulation during the melt season. Passive microwave sensors offer real-time global SWE estimates but suffer from several issues, notably signal loss in wet snow or in forests, saturation in deep snow, subpixel variability in the mountains owing to the large (~25 km) pixel size, and SWE overestimation in the presence of large grains such as depth and surface hoar. Throughout the winter and spring, snow-covered area can be measured at sub-km spatial resolution with optical sensors, with accuracy and timeliness improved by interpolating and smoothing across multiple days. So the question is, how can we establish the relationship between Reconstruction—available only after the snow goes away—and passive microwave and optical data to accurately estimate SWE during the snow season, when the information can help forecast spring runoff? Linear regression provides one answer, but can modern machine learning techniques (used to persuade people to click on web advertisements) adapt to improve forecasts of floods and droughts in areas where more than one billion people depend on snowmelt for their water resources?
Directory of Open Access Journals (Sweden)
Wen-Yeau Chang
2013-01-01
Full Text Available This paper proposes an equivalent circuit parameters measurement and estimation method for proton exchange membrane fuel cell (PEMFC. The parameters measurement method is based on current loading technique; in current loading test a no load PEMFC is suddenly turned on to obtain the waveform of the transient terminal voltage. After the equivalent circuit parameters were measured, a hybrid method that combines a radial basis function (RBF neural network and enhanced particle swarm optimization (EPSO algorithm is further employed for the equivalent circuit parameters estimation. The RBF neural network is adopted such that the estimation problem can be effectively processed when the considered data have different features and ranges. In the hybrid method, EPSO algorithm is used to tune the connection weights, the centers, and the widths of RBF neural network. Together with the current loading technique, the proposed hybrid estimation method can effectively estimate the equivalent circuit parameters of PEMFC. To verify the proposed approach, experiments were conducted to demonstrate the equivalent circuit parameters estimation of PEMFC. A practical PEMFC stack was purposely created to produce the common current loading activities of PEMFC for the experiments. The practical results of the proposed method were studied in accordance with the conditions for different loading conditions.
Kim, R. S.; Durand, M. T.
2016-12-01
This paper presents and illustrates improved retrieval method of snow water equivalent (SWE) from airborne passive microwave (PM) measurements. A particle filter approach is proposed to assimilate PM brightness temperature (Tb) data in order to update snowpack states in a land surface model and demonstrates compared to ensemble Kalman filter (EnKF) method. The methods were applied over the Yampa river basin in the Colorado Rockies within the NASA Cold Land Processes Experiment (CLPX) area of 2002-2003. Forcing data is derived from the North American Land Data Assimilation v2 (NLDAS-2) dataset and Microwave Emission Model of Layered Snowpacks (MEMLS) is used to convert the snow state variables to Tb. The effects of vegetation and atmosphere are included in the radiative transfer model (RTM). Multifrequency measurements of PSR (Polarimetric Scanning Radiometer) are used and assimilated into model predictions of SWE at 120-m spatial resolution. The contributions of each channel to recover the true SWE are computed and analyzed. The SWE estimation is validated against SNOTEL and snow course observations.
Implementation of Equilibrium-Price Model to the Estimation of Import Inflation
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Yadulla Hasanli
2015-04-01
Full Text Available This study aims at investigating the the import inflationary processes as a result of feedbacks of mutual economic relations of World countries. It is used Equilibrium Price Model to estimate the import inflationary processes in CIS countries. The study investigates the further results regarding the import inflationary processes in the CIS countries on the scenario of increasing the Value Added norm in Russia. As well as by standpoint of economic growth and price stability, the recent revaluation of US dollar in the World and its impacts to total output of other countries have been investigated in details. In other words due to revaluation of the US dollar, if the final product decreases in USA, this decreasing impact how to be transmitted to the world countries have been estimated by the Input-Output Table in this study as well. The work is fulfilled on the Input-Output data for the year 2011. This study assumes theoretical and practical importance in defining the monetary policy.
Fitting Equilibrium Search Models to Labour Market Data
DEFF Research Database (Denmark)
Bowlus, Audra J.; Kiefer, Nicholas M.; Neumann, George R.
1996-01-01
Specification and estimation of a Burdett-Mortensen type equilibrium search model is considered. The estimation is nonstandard. An estimation strategy asymptotically equivalent to maximum likelihood is proposed and applied. The results indicate that specifications with a small number of productiv......Specification and estimation of a Burdett-Mortensen type equilibrium search model is considered. The estimation is nonstandard. An estimation strategy asymptotically equivalent to maximum likelihood is proposed and applied. The results indicate that specifications with a small number...... of productivity types fit the data well compared to the homogeneous model....
Phantom-derived estimation of effective dose equivalent from X rays with and without a lead apron.
Mateya, C F; Claycamp, H G
1997-06-01
Organ dose equivalents were measured in a humanoid phantom in order to estimate effective dose equivalent (H(E)) and effective dose (E) from low-energy x rays and in the presence or absence of a protective lead apron. Plane-parallel irradiation conditions were approximated using direct x-ray beams of 76 and 104 kVp and resulting dosimetry data was adjusted to model exposures conditions in fluoroscopy settings. Values of H(E) and E estimated under-shielded conditions were compared to the results of several recent studies that used combinations of measured and calculated dosimetry to model exposures to radiologists. While the estimates of H(E) and E without the lead apron were within 0.2 to 20% of expected values, estimates based on personal monitors worn at the (phantom) waist (underneath the apron) underestimated either H(E) or E while monitors placed at the neck (above the apron) significantly overestimated both quantities. Also, the experimentally determined H(E) and E were 1.4 to 3.3 times greater than might be estimated using recently reported "two-monitor" algorithms for the estimation of effective dose quantities. The results suggest that accurate estimation of either H(E) or E from personal monitors under conditions of partial body exposures remains problematic and is likely to require the use of multiple monitors.
Low-sampling-rate ultra-wideband channel estimation using equivalent-time sampling
Ballal, Tarig
2014-09-01
In this paper, a low-sampling-rate scheme for ultra-wideband channel estimation is proposed. The scheme exploits multiple observations generated by transmitting multiple pulses. In the proposed scheme, P pulses are transmitted to produce channel impulse response estimates at a desired sampling rate, while the ADC samples at a rate that is P times slower. To avoid loss of fidelity, the number of sampling periods (based on the desired rate) in the inter-pulse interval is restricted to be co-prime with P. This condition is affected when clock drift is present and the transmitted pulse locations change. To handle this case, and to achieve an overall good channel estimation performance, without using prior information, we derive an improved estimator based on the bounded data uncertainty (BDU) model. It is shown that this estimator is related to the Bayesian linear minimum mean squared error (LMMSE) estimator. Channel estimation performance of the proposed sub-sampling scheme combined with the new estimator is assessed in simulation. The results show that high reduction in sampling rate can be achieved. The proposed estimator outperforms the least squares estimator in almost all cases, while in the high SNR regime it also outperforms the LMMSE estimator. In addition to channel estimation, a synchronization method is also proposed that utilizes the same pulse sequence used for channel estimation. © 2014 IEEE.
Using Simple Quadratic Equations to Estimate Equilibrium Concentrations of an Acid
Brilleslyper, Michael A.
2004-01-01
Application of quadratic equations to standard problem in chemistry like finding equilibrium concentrations of ions in an acid solution is explained. This clearly shows that pure mathematical analysis has meaningful applications in other areas as well.
Estimating the Equivalent Energy for Single Super Phosphate Production in Iran
Payman Salami; Hojat Ahmadi; Alireza Keyhani
2010-01-01
Fertilizer is a major factor in expanding food output. Fertilizer production is also highly energy-intensive. The aim of this study is to determine the equivalent energy for Single Super Phosphate (SSP) fertilizer production in Iran. This study was carried out in a fertilizer plant in Sanandaj city. The primary energy resources that were utilized in the plant for single superphosphate fertilizer production were natural gas, electrical and human energy. The raw materials that were used in the ...
Estimate of Equilibrium Real Exchange Rate and Misalignment of Chinese Yuan Vis-a-Vis US Dollar
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Atabani Adi Agya
2015-09-01
Full Text Available The paper examines the misalignment in equilibrium real exchange rate of Chinese Yuan against US dollar. The data covered the period of 1980-2014, it used Vector Autoregressive model, the variables are not stationary at level and became stationary after first differencing and there were three co-integration vectors. The long run coefficients have expected sign except for interest rate differential and are significant at 5 percent significance level. The speed of adjustment of real exchange rate to it equilibrium indicated that the disequilibrium in the last period are corrected by 87 percent each year and highly significant. The Yuan was overvalued by 4 percent, from 1981-1990 and in1990 it was undervalue about 4 percent and move back to equilibrium, the highest overvaluation was in 1993 up to 13 percent from equilibrium value and undervalue in 1994 by 14 percent which was the highest level of undervaluation, between 1996 to 2005 the Yuan was relatively within it equilibrium and slightly over value to 3.8 percent in 2008 back to long time path in 2011 and relatively undervalue by 1-3 percent since 2012, in general the Yuan is not substantially undervalue as claims in some studies both theoretical and empirical estimation and the movement in the exchange rate are consistent with economic fundamental of China.
González-Méijome, José M; López-Alemany, Antonio; Lira, Madalena; Almeida, José B; Oliveira, M Elisabete C D Real; Parafita, Manuel A
2007-01-01
The purpose of the present study was to develop mathematical relationships that allow obtaining equilibrium water content and refractive index of conventional and silicone hydrogel soft contact lenses from refractive index measures obtained with automated refractometry or equilibrium water content measures derived from manual refractometry, respectively. Twelve HEMA-based hydrogels of different hydration and four siloxane-based polymers were assayed. A manual refractometer and a digital refractometer were used. Polynomial models obtained from the sucrose curves of equilibrium water content against refractive index and vice-versa were used either considering the whole range of sucrose concentrations (16-100% equilibrium water content) or a range confined to the equilibrium water content of current soft contact lenses (approximately 20-80% equilibrium water content). Values of equilibrium water content measured with the Atago N-2E and those derived from the refractive index measurement with CLR 12-70 by the applications of sucrose-based models displayed a strong linear correlation (r2 = 0.978). The same correlations were obtained when the models are applied to obtain refractive index values from the Atago N-2E and compared with those (values) given by the CLR 12-70 (r2 = 0.978). No significantly different results are obtained between models derived from the whole range of the sucrose solution or the model limited to the normal range of soft contact lens hydration. Present results will have implications for future experimental and clinical research regarding normal hydration and dehydration experiments with hydrogel polymers, and particularly in the field of contact lenses. 2006 Wiley Periodicals, Inc.
Kim, Dohyun; Lee, Jongshill; Park, Hoon Ki; Jang, Dong Pyo; Song, Soohwa; Cho, Baek Hwan; Jung, Yoo-Suk; Park, Rae-Woong; Joo, Nam-Seok; Kim, In Young
2017-07-01
The purpose of the study is to analyse how the standard of resting metabolic rate (RMR) affects estimation of the metabolic equivalent of task (MET) using an accelerometer. In order to investigate the effect on estimation according to intensity of activity, comparisons were conducted between the 3.5 ml O 2 · kg -1 · min -1 and individually measured resting VO 2 as the standard of 1 MET. MET was estimated by linear regression equations that were derived through five-fold cross-validation using 2 types of MET values and accelerations; the accuracy of estimation was analysed through cross-validation, Bland and Altman plot, and one-way ANOVA test. There were no significant differences in the RMS error after cross-validation. However, the individual RMR-based estimations had as many as 0.5 METs of mean difference in modified Bland and Altman plots than RMR of 3.5 ml O 2 · kg -1 · min -1 . Finally, the results of an ANOVA test indicated that the individual RMR-based estimations had less significant differences between the reference and estimated values at each intensity of activity. In conclusion, the RMR standard is a factor that affects accurate estimation of METs by acceleration; therefore, RMR requires individual specification when it is used for estimation of METs using an accelerometer.
Dai, Haifeng; Zhu, Letao; Zhu, Jiangong; Wei, Xuezhe; Sun, Zechang
2015-10-01
The accurate monitoring of battery cell temperature is indispensible to the design of battery thermal management system. To obtain the internal temperature of a battery cell online, an adaptive temperature estimation method based on Kalman filtering and an equivalent time-variant electrical network thermal (EENT) model is proposed. The EENT model uses electrical components to simulate the battery thermodynamics, and the model parameters are obtained with a least square algorithm. With a discrete state-space description of the EENT model, a Kalman filtering (KF) based internal temperature estimator is developed. Moreover, considering the possible time-varying external heat exchange coefficient, a joint Kalman filtering (JKF) based estimator is designed to simultaneously estimate the internal temperature and the external thermal resistance. Several experiments using the hard-cased LiFePO4 cells with embedded temperature sensors have been conducted to validate the proposed method. Validation results show that, the EENT model expresses the battery thermodynamics well, the KF based temperature estimator tracks the real central temperature accurately even with a poor initialization, and the JKF based estimator can simultaneously estimate both central temperature and external thermal resistance precisely. The maximum estimation errors of the KF- and JKF-based estimators are less than 1.8 °C and 1 °C respectively.
Coeli M. Hoover; James E. Smith
2017-01-01
Assessments of forest carbon are available via multiple alternate tools or applications and are in use to address various regulatory and reporting requirements. The various approaches to making such estimates may or may not be entirely comparable. Knowing how the estimates produced by some commonly used approaches vary across forest types and regions allows users of...
DEFF Research Database (Denmark)
Gonzalez Eiras, Martin; Niepelt, Dirk
2015-01-01
and a state are equivalent to another such pair if both pairs give rise to the same allocation in politico-economic equilibrium. The equivalence conditions help to identify factors that render institutional change non-neutral and to construct politico-economic equilibria in new policy regimes. We exemplify......Traditional "economic equivalence'' results, like the Ricardian equivalence proposition, define equivalence classes over exogenous policies. We derive "politico-economic equivalence" conditions that apply in environments where policy is endogenous and chosen sequentially. A policy regime...
Energy Technology Data Exchange (ETDEWEB)
Valle H, J.; Morales S, J. B. [UNAM, DEPFI, Laboratorio de Analisis de Ingenieria de Reactores Nucleares, Campus Morelos en IMTA, Jiutepec, Morelos (Mexico); Espinosa P, G., E-mail: julfi_ig@yahoo.com.m [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Av. San Rafael Atlixco No. 186, Col. Vicentina, 09340 Mexico D. F. (Mexico)
2010-10-15
This work presents the design and implementation of an advanced controller for a reduced order model of a BWR reactor core cooled by natural circulating water, which allows real time estimates of coolant flows through fuel assemblies about standard neutron flux strings. Nuclear power plants with boiling water reactors control individual fuel assembly coolant flows by forced circulation using external or internal water pumps and different core support plate orifices. These two elements reduce flow dependency on local channel pressure drops. In BWR reactors using only natural circulation coolant flows, these two elements are not available and therefore individual channel coolant flows are highly dependent in local conditions, such as power distributions and local pressure drops. Therefore it is expected that grater uncertainties in these variables be used during safety, fuel management and other analysis, which in turns may lead to increased operation penalties, such as tighter operating limits. The objective of this work is to asses by computer simulations means to reduce uncertainties in the measurement of fuel assembly coolant flows and eventually the associated penalties. During coolant phase transitions, pressure drops and local power may alter local natural circulation through fuel assemblies and flow estimates can be helped or not by control rod moves. This work presents the construction of an optimal controller for a core flow estimator based on a reduced order model of the coolant going though the reactor vessel components and nuclear core. This model is to be driven by plant signals from standard BWR instrumentation in order to estimate the coolant flows in selected fuel assemblies about a LPRM string. For this purpose an equivalent electrical model has been mathematically developed and numerically tested. The power-flow maps of typical BRW are used as steady state references for this equivalent model. Once these were fully reproduced for steady state
Directory of Open Access Journals (Sweden)
Seyed Rohollah Hosseini Vaez
2017-08-01
Full Text Available In this study the ability of equivalent pulse extracted by a mathematical model from pulse-like ground motion is investigated in order to estimate the response of RC moment-resisting frames. By examining the mathematical model, it is obvious that the model-based elastic response spectra are compatible with the actual pulse-like record. Also, the model simulates the long-period portion of actual pulse-like records by a high level of precision. The results indicate that the model adequately simulates the components of time histories. In order to investigate the ability of equivalent pulse of pulse-like ground motion in estimating the response of RC moment-resisting frames, five frame models including 3, 6, 9, 12 and 15 stories analyzed under actual record and simulated one. The results of the base shear demand, the maximum value of the inter-story drift and the distribution of inter-story drift along the height of the structures in three levels of design ductility is investigated. According to the results of this study, the equivalent pulses can predict accurately the response of regular RC moment-resisting frames when the fundamental period of the structure is equal to or greater than the equivalent pulse of the record. For the ground motion with high-frequency content the difference is high; but with increasing the number of stories and approaching pulse period to the fundamental period of the structure and increasing the level of design ductility of structure, more accurately predict the structural response.
Equivalent dose estimation using a single aliquot of polymineral fine grains
DEFF Research Database (Denmark)
Banerjee, D.; Murray, A.S.; Bøtter-Jensen, L.
2001-01-01
a blue detection window, and also with expected values of D-e based on independent age estimates and measured dose rates. We conclude that post-IR blue-stimulated luminescence provides reliable estimates of D-e, and that these are probably superior to the IRSL estimates obtained using both near-UV......-stimulated luminescence, and (iii) blue-stimulated luminescence following infrared (IR) stimulation, using a near-UV (290-380 nm) detection window in each case. For these three signals, there is a significant change in sensitivity with regeneration cycle; this change can be compensated for using the response to a fixed...... test dose after each natural or regenerated measurement. The source of the three luminescence signals is then investigated using pulse-anneal and elevated-temperature experiments. Fading tests on laboratory-induced signals show that although the IR signals fade by up to 23% in 15 days at 100 degrees...
Ingvander, Susanne; Brown, Ian
2013-12-01
Estimating the snow water equivalent (SWE) of the seasonal snowpack is key information for the prediction of spring flood rates and the contribution to water reservoirs in Hydro-power production. By establishing the relationship between accumulation patterns and physical parameters in the landscape such as topographic features and vegetation, a model of accumulation patterns in different types of reference areas can be produced. However, detailed information on the spatial and temporal evolution of the snow pack is necessary in order to develop such an algorithm. By determining the frequency and amplitude of topography in the Swedish mountain regions and by measuring snow accumulation in these regions we can increase the accuracy of the estimation of SWE. This information can then aid the understanding of scaling issues over the region. Satellite imagery and products can then be used for up-scaling from high-resolution field data to derive new satellite algorithms in the future.
Directory of Open Access Journals (Sweden)
Felice Arena
2015-10-01
Full Text Available The design of any wave energy converter involves the determination of relevant statistical data on the wave energy resource oriented to the evaluation of the structural reliability and energy performance of the device. Currently, limited discussions concern the estimation of parameters connected to the energy performance of a device. Thus, this paper proposes a methodology for determining average downtime and average missed energy, which is the energy that is not harvested because of device deactivations during severe sea storms. These quantities are fundamental for evaluating the expected inactivity of a device during a year or during its lifetime and are relevant for assessing the effectiveness of a device working at a certain site. For this purpose, the equivalent power storm method is used for their derivation, starting from concepts pertaining to long-term statistical analysis. The paper shows that the proposed solutions provide reliable estimations via comparison with results obtained by processing long wave data.
Directory of Open Access Journals (Sweden)
Jinxin Fan
2011-03-01
Full Text Available To improve the use of lithium-ion batteries in electric vehicle (EV applications, evaluations and comparisons of different equivalent circuit models are presented in this paper. Based on an analysis of the traditional lithium-ion battery equivalent circuit models such as the Rint, RC, Thevenin and PNGV models, an improved Thevenin model, named dual polarization (DP model, is put forward by adding an extra RC to simulate the electrochemical polarization and concentration polarization separately. The model parameters are identified with a genetic algorithm, which is used to find the optimal time constant of the model, and the experimental data from a Hybrid Pulse Power Characterization (HPPC test on a LiMn2O4 battery module. Evaluations on the five models are carried out from the point of view of the dynamic performance and the state of charge (SoC estimation. The dynamic performances of the five models are obtained by conducting the Dynamic Stress Test (DST and the accuracy of SoC estimation with the Robust Extended Kalman Filter (REKF approach is determined by performing a Federal Urban Driving Schedules (FUDS experiment. By comparison, the DP model has the best dynamic performance and provides the most accurate SoC estimation. Finally, sensitivity of the different SoC initial values is investigated based on the accuracy of SoC estimation with the REKF approach based on the DP model. It is clear that the errors resulting from the SoC initial value are significantly reduced and the true SoC is convergent within an acceptable error.
Girotto, M.; Margulis, S. A.; Durand, M. T.; Molotch, N. P.
2010-12-01
Seasonal snowmelt runoff represents one of the major components of water resources in many regions of the world. Lack of knowledge of its spatial and temporal characteristics limits our ability to monitor and predict this vital source of water. Process understanding stands to benefit from an accurate spatial and temporal characterization of the mountain snow water equivalent (SWE) spatial distribution and evolution. A probabilistic approach that takes into account sources of uncertainty from all input data streams (including remote sensing and models and their inputs) while estimating SWE is desired. This work applied a Bayesian reanalysis data assimilation system, similar to an Ensemble Kalman Smoother, capable of merging remotely sensed Snow Covered Area (SCA) data into prediction models, and at the same time account for the limitations of each. Preliminary analysis has identified and characterized the key factors responsible for SWE estimation accuracy, and developed models able to represent their uncertainties within the probabilistic data assimilation approach. The approach was implemented for the characterization of spatially and temporally continuous SWE over a test domain in the Sequoia National Park region of the Sierra Nevada. To assess the performance of the method, SWE spatial estimates are compared with estimates from intense field campaigns, and existing snow-pillow records. SCA estimates from both the standard fractional MODIS product and the advanced MODSCAG are investigated as they have been derived with different retrieval algorithms. The system is designed to use readily available forcing information from the North American Land Data Assimilation System (NLDAS). Prior estimates of SWE are obtained by forcing a land surface model with prior probability distributions of snowfall obtained from the NLDAS precipitation product. A reanalysis step conditions the prior estimates on SCA measurements. A series of preliminary analyses focus on identifying
Estimation of CO2-Equivalent Emission under the Copper Fire Refining Process
Chesnokov, Yu N.; Lisienko, V. G.; Holod, S. I.; Anufriev, V. P.; Lapteva, A. V.
2017-06-01
Non-ferrous metallurgy is one of the most energy-consuming and carbon-emissive sectors of industry. This is due to the fact that the volume of greenhouse gas (GHG) emissions is stipulated by energy consumption. Uralelectromed is a city-forming enterprise of the Verkhnyaya Pyshma. The situation is similar other cities of the old industrial regions of the Russian Federation (Krasnouralsk, Verkhnaya Salda, Karabash, etc.) Verkhnyaya Pyshma has many characteristics of “a clever city”. It can be compared to Hamburg where blister copper is being produced at the center of the city at a copper smelting plant Aurubis. Following the example of such ecologically clean country as Germany and in order to assess how modern energy-efficient low-carbon technologies can provide a favorable habitat, and an acceptable level of carbon footprint, the authors estimated the level of greenhouse gas, i.e., carbon dioxide emission produced by the Uralelectromed. The emission of greenhouse gas -carbon dioxide in the process of fire refining of blister copper has been calculated. The anode melting process consists of several stages where the most important ones are melting of charge, oxidation, and copper melt reduction. Calculations are based on taking into account the mass of burnt carbon of natural gas and the thermal dissociation of fuel oil. It implies that a complete combustion of carbon takes place. The specific value of carbon dioxide emission of the copper refining process is averaged 181 kg CO2 per 1 ton of anode copper.
Energy Technology Data Exchange (ETDEWEB)
Karanam, Aditya; Sharma, Pavan K.; Ganju, Sunil; Singh, Ram Kumar [Bhabha Atomic Research Centre (BARC), Mumbai (India). Reactor Safety Div.
2016-12-15
During postulated accident sequences in nuclear reactors, hydrogen may get released from the core and form a flammable mixture in the surrounding containment structure. Ignition of such mixtures and the subsequent pressure rise are an imminent threat for safe and sustainable operation of nuclear reactors. Methods for evaluating post ignition characteristics are important for determining the design safety margins in such scenarios. This study presents two thermo-chemical models for determining the post ignition state. The first model is based on internal energy balance while the second model uses the concept of element potentials to minimize the free energy of the system with internal energy imposed as a constraint. Predictions from both the models have been compared against published data over a wide range of mixture compositions. Important differences in the regions close to flammability limits and for stoichiometric mixtures have been identified and explained. The equilibrium model has been validated for varied temperatures and pressures representative of initial conditions that may be present in the containment during accidents. Special emphasis has been given to the understanding of the role of dissociation and its effect on equilibrium pressure, temperature and species concentrations.
Dou, Wenjie; Subotnik, Joseph E.
2017-09-01
For a molecule moving near a single metal surface at equilibrium, following von Oppen and coworkers [N. Bode, S. V. Kusminskiy, R. Egger, and F. von Oppen, Beilstein J. Nanotechnol. 3, 144 (2012), 10.3762/bjnano.3.15] and using a nonequilibrium Green's-function (NEGF) approach, we derive a very general form of electronic friction that includes non-Condon effects. We then demonstrate that the resulting NEGF friction tensor agrees exactly with the Head-Gordon-Tully model, provided that finite temperature effects are incorporated correctly. The present results are in agreement with our recent claim that there is only one universal electronic friction tensor arising from the Born-Oppenheimer approximation [W. Dou, G. Miao, and J. E. Subotnik, Phys. Rev. Lett. 119, 046001 (2017), 10.1103/PhysRevLett.119.046001].
Sankey, T.; Springer, A. E.; O'Donnell, F. C.; Donald, J.; McVay, J.; Masek Lopez, S.
2014-12-01
The U.S. Forest Service plans to conduct forest restoration treatments through the Four Forest Restoration Initiative (4FRI) on hundreds of thousands of acres of ponderosa pine forest in northern Arizona over the next 20 years with the goals of reducing wildfire hazard and improving forest health. The 4FRI's key objective is to thin and burn the forests to create within-stand openings that "promote snowpack accumulation and retention which benefit groundwater recharge and watershed processes at the fine (1 to 10 acres) scale". However, little is known about how these openings created by restoration treatments affect snow water equivalence (SWE) and soil moisture, which are key parts of the water balance that greatly influence water availability for healthy trees and for downstream water users in the Sonoran Desert. We have examined forest canopy cover by calculating a Normalized Difference Vegetation Index (NDVI), a key indicator of green vegetation cover, using Landsat satellite data. We have then compared NDVI between treatments at our study sites in northern Arizona and have found statistically significant differences in tree canopy cover between treatments. The control units have significantly greater forest canopy cover than the treated units. The thinned units also have significantly greater tree canopy cover than the thin-and-burn units. Winter season Landsat images have also been analyzed to calculate Normalized Difference Snow Index (NDSI), a key indicator of snow water equivalence and snow accumulation at the treated and untreated forests. The NDSI values from these dates are examined to determine if snow accumulation and snow water equivalence vary between treatments at our study sites. NDSI is significantly greater at the treated units than the control units. In particular, the thinned forest units have significantly greater snow cover than the control units. Our results indicate that forest restoration treatments result in increased snow pack
Nagamine, Shuji; Fujibuchi, Toshioh; Umezu, Yoshiyuki; Himuro, Kazuhiko; Awamoto, Shinichi; Tsutsui, Yuji; Nakamura, Yasuhiko
2017-03-01
In this study, we estimated the ambient dose equivalent rate (hereafter "dose rate") in the fluoro-2-deoxy-D-glucose (FDG) administration room in our hospital using Monte Carlo simulations, and examined the appropriate medical-personnel locations and a shielding method to reduce the dose rate during FDG injection using a lead glass shield. The line source was assumed to be the FDG feed tube and the patient a cube source. The dose rate distribution was calculated with a composite source that combines the line and cube sources. The dose rate distribution was also calculated when a lead glass shield was placed in the rear section of the lead-acrylic shield. The dose rate behind the automatic administration device decreased by 87 % with respect to that behind the lead-acrylic shield. Upon positioning a 2.8-cm-thick lead glass shield, the dose rate behind the lead-acrylic shield decreased by 67 %.
Zardad, Asma; Mohsin, Asma; Zaman, Khalid
2013-12-01
The purpose of this study is to investigate the factors that affect real exchange rate volatility for Pakistan through the co-integration and error correction model over a 30-year time period, i.e. between 1980 and 2010. The study employed the autoregressive conditional heteroskedasticity (ARCH), generalized autoregressive conditional heteroskedasticity (GARCH) and Vector Error Correction model (VECM) to estimate the changes in the volatility of real exchange rate series, while an error correction model was used to determine the short-run dynamics of the system. The study is limited to a few variables i.e., productivity differential (i.e., real GDP per capita relative to main trading partner); terms of trade; trade openness and government expenditures in order to manage robust data. The result indicates that real effective exchange rate (REER) has been volatile around its equilibrium level; while, the speed of adjustment is relatively slow. VECM results confirm long run convergence of real exchange rate towards its equilibrium level. Results from ARCH and GARCH estimation shows that real shocks volatility persists, so that shocks die out rather slowly, and lasting misalignment seems to have occurred.
Estimation of In-Situ Groundwater Conditions Based on Geochemical Equilibrium Simulations
Directory of Open Access Journals (Sweden)
Toshiyuki Hokari
2014-03-01
Full Text Available This paper presents a means of estimating in-situ groundwater pH and oxidation-redox potential (ORP, two very important parameters for species migration analysis in safety assessments for radioactive waste disposal or carbon dioxide sequestration. The method was applied to a pumping test in a deep borehole drilled in a tertiary formation in Japan for validation. The following application examples are presented: when applied to several other pumping tests at the same site, it could estimate distributions of the in-situ groundwater pH and ORP; applied to multiple points selected in the groundwater database of Japan, it could help estimate the in-situ redox reaction governing the groundwater conditions in some areas.
Cavallaro, Michael C; Morrissey, Christy A; Headley, John V; Peru, Kerry M; Liber, Karsten
2017-02-01
Nontarget aquatic insects are susceptible to chronic neonicotinoid insecticide exposure during the early stages of development from repeated runoff events and prolonged persistence of these chemicals. Investigations on the chronic toxicity of neonicotinoids to aquatic invertebrates have been limited to a few species and under different laboratory conditions that often preclude direct comparisons of the relative toxicity of different compounds. In the present study, full life-cycle toxicity tests using Chironomus dilutus were performed to compare the toxicity of 3 commonly used neonicotinoids: imidacloprid, clothianidin, and thiamethoxam. Test conditions followed a static-renewal exposure protocol in which lethal and sublethal endpoints were assessed on days 14 and 40. Reduced emergence success, advanced emergence timing, and male-biased sex ratios were sensitive responses to low-level neonicotinoid exposure. The 14-d median lethal concentrations for imidacloprid, clothianidin, and thiamethoxam were 1.52 μg/L, 2.41 μg/L, and 23.60 μg/L, respectively. The 40-d median effect concentrations (emergence) for imidacloprid, clothianidin, and thiamethoxam were 0.39 μg/L, 0.28 μg/L, and 4.13 μg/L, respectively. Toxic equivalence relative to imidacloprid was estimated through a 3-point response average of equivalencies calculated at 20%, 50%, and 90% lethal and effect concentrations. Relative to imidacloprid (toxic equivalency factor [TEF] = 1.0), chronic (lethality) 14-d TEFs for clothianidin and thiamethoxam were 1.05 and 0.14, respectively, and chronic (emergence inhibition) 40-d TEFs were 1.62 and 0.11, respectively. These population-relevant endpoints and TEFs suggest that imidacloprid and clothianidin exert comparable chronic toxicity to C. dilutus, whereas thiamethoxam induced comparable effects only at concentrations an order of magnitude higher. However, the authors caution that under field conditions, thiamethoxam readily degrades to
Energy Technology Data Exchange (ETDEWEB)
Irazola, L; Terron, J; Sanchez-Doblado, F [Departamento de Fisiologia Medica y Biofisica, Universidad de Sevilla (Spain); Servicio de Radiofisica, Hospital Universitario Virgen Macarena, Sevilla (Spain); Domingo, C; Romero-Exposito, M [Departament de Fisica, Universitat Autonoma de Barcelona, Bellaterra (Spain); Garcia-Fuste, M [Health and Safety Department, ALBA Synchrotron Light Source, Cerdanyola del Valles (Spain); Sanchez-Nieto, B [Instituto de Fisica, Pontificia Universidad Catolica de Chile, Santiago (Chile); Bedogni, R [Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare (INFN) (Italy)
2015-06-15
Purpose: Previous measurements with Bonner spheres{sup 1} showed that normalized neutron spectra are equal for the majority of the existing linacs{sup 2}. This information, in addition to thermal neutron fluences obtained in the characterization procedure{sup 3}3, would allow to estimate neutron doses accidentally received by exposed workers, without the need of an extra experimental measurement. Methods: Monte Carlo (MC) simulations demonstrated that the thermal neutron fluence distribution inside the bunker is quite uniform, as a consequence of multiple scatter in the walls{sup 4}. Although inverse square law is approximately valid for the fast component, a more precise calculation could be obtained with a generic fast fluence distribution map around the linac, from MC simulations{sup 4}. Thus, measurements of thermal neutron fluences performed during the characterization procedure{sup 3}, together with a generic unitary spectra{sup 2}, would allow to estimate the total neutron fluences and H*(10) at any point{sup 5}. As an example, we compared estimations with Bonner sphere measurements{sup 1}, for two points in five facilities: 3 Siemens (15–23 MV), Elekta (15 MV) and Varian (15 MV). Results: Thermal neutron fluences obtained from characterization, are within (0.2–1.6×10{sup 6}) cm−{sup 2}•Gy{sup −1} for the five studied facilities. This implies ambient equivalent doses ranging from (0.27–2.01) mSv/Gy 50 cm far from the isocenter and (0.03–0.26) mSv/Gy at detector location with an average deviation of ±12.1% respect to Bonner measurements. Conclusion: The good results obtained demonstrate that neutron fluence and H*(10) can be estimated based on: (a) characterization procedure established for patient risk estimation in each facility, (b) generic unitary neutron spectrum and (c) generic MC map distribution of the fast component. [1] Radiat. Meas (2010) 45: 1391 – 1397; [2] Phys. Med. Biol (2012) 5 7:6167–6191; [3] Med. Phys (2015) 42
National Research Council Canada - National Science Library
Jauhari Dahalan; Mohammed Umar; Hussin Abdullah
2016-01-01
To evaluate the existence of possible over and under valuation of exchange rate for Malaysia, the study examines the nature of misalignment in the equilibrium real exchange rate and its systemic...
KULAKSIZ, Ahmet Afşin
2012-01-01
The performance and system cost of photovoltaic (PV) systems can be improved by employing high-efficiency power conditioners with maximum power point tracking (MPPT) methods. Fast implementation and accurate operation of MPPT controllers can be realized by modeling the characteristics of PV modules, obtaining equivalent parameters. In this study, adaptive neuro-fuzzy inference systems (ANFISs) have been used to obtain 3 of the parameters in a single-diode model of PV cells, namely serie...
Directory of Open Access Journals (Sweden)
Jillian L. Waid
2017-10-01
Full Text Available This dataset contains Adult Male Equivalent (AME values for use in Bangladesh. These were constructed using prescriptive nutritional constructs adapted to the actual growth and weight pattern seen in Bangladesh. This dataset provides a common base to facilitate for future work with household consumption and expenditure data in Bangladesh while updating the average energy requirements for infants and young children for the WHO 2006 growth standards and 2007 growth reference curves.
Coeli M. Hoover; James E. Smith
2017-01-01
The focus on forest carbon estimation accompanying the implementation of increased regulatory and reporting requirements is fostering the development of numerous tools and methods to facilitate carbon estimation. One such well-established mechanism is via the Forest Vegetation Simulator (FVS), a growth and yield modeling system used by public and private land managers...
DEFF Research Database (Denmark)
Nieto Solana, Hector; Sandholt, Inge; Aguado, Inmaculada
2010-01-01
humidity. The input data were acquired by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) sensor, on board the Meteosat Second Generation (MSG) satellite, from which air temperature and relative humidity were estimated every 15 min. Air temperature estimations are based on the Temperature......In this study we propose to use remote sensing data to estimate hourly meteorological data and then assess the moisture content of dead fuels. Three different models to estimate the equilibrium moisture content (EMC) were applied together with remotely sensed retrieved air temperature and relative......, a linear relationship between precipitable water content and vapour pressure has been derived. Precipitable water content was estimated with the thermal infrared bands of SEVIRI using a split-window algorithm and data from ground meteorological stations in Spain during the year 2005 were used to calibrate...
Energy Technology Data Exchange (ETDEWEB)
Gerken, M.; Kreienbrock, L. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Inst. fuer Epidemiologie; Peter, J. [Bundesamt fuer Strahlenschutz, Oberschleissheim (Germany). Inst. fuer Strahlenhygiene
1997-10-01
To investigate the influence of various factors on indoor concentration of radon and progeny a joint project was carried out by the Institute for Radiation Protection and the Institute for Epidemiology of the GSF - National Research Center for Environment and Health. By means of an active measurement device the concentrations of radon decay products in several Bavarian houses were measured continuously from 1993 to 1995. The measurements took place under everyday life conditions and are compared to radon concentrations measured by passive dosimeters. Informations on house characteristics and airing habits were collected from the inhabitants. Controlled ventilation experiments were conducted in some of the dwellings. This report describes the results of 38 series of measurements in 31 houses with a minimum duration of three months. A detailed description for every series is given on: - house and room characteristics - temporal course of equilibrium equivalent radon concentration - mean activity concentration and variance - comparison with radon concentration delivered by passive measurement devices, graphical presentation of - day to day variation - seasonal variation - diurnal variation for a part of the houses - results of controlled ventilation experiments. (orig./GL) [Deutsch] Zur Bestimmung von Einflussfaktoren fuer die Innenraumkonzentration von Radon und seinen Zerfallprodukten wurden in einem gemeinsamen Projekt des Institutes fuer Strahlenschutz und des Institutes fuer Epidemiologie der GSF Forschungszentrum fuer Umwelt und Gesundheit Messreihen durchgefuehrt. Mit einem kontinuierlichen Messsystem wurden hierbei in den Jahren 1992 bis 1995 die zeitlichen Verlaeufe der Konzentration der Radonzerfallsprodukte in verschiedenen bayerischen Wohnungen unter Alltagsbedingungen aufgezeichnet und den in diesen Wohnungen vermittels Passivdosimetern gemessenen Radongaskonzentrationen gegenuebergestellt. Zusaetzlich wurden Angaben zu Wohnbedingungen und
Ohba, Takashi; Hasegawa, Arifumi; Kohayakawa, Yoshitaka; Kondo, Hisayoshi; Suzuki, Gen
2017-09-01
To reduce uncertainty in thyroid dose estimation, residents' radiation protection behavior should be reflected in the estimation. Screening data of body surface contamination provide information on exposure levels during evacuation. Our purpose is to estimate thyroid equivalent doses based on body surface contamination levels using a new methodology. We obtained a record of 7,539 residents/evacuees. Geiger-Mueller survey meter measurement value in cpm was translated into Bq/cm2 according to the nuclides densities obtained by measuring clothing from two persons by germanium γ-spectrometer. The measurement value of body surface contamination on head was adjusted by a natural removal rate of 15 hours and radionuclides' physical half-life. Thyroid equivalent dose of 1-year-old children by inhalation was estimated by two-dimensional Monte Carlo simulation. The proportions of evacuees/residents with measurement value in cpm of Namie and Minamisoma groups were higher than those of other groups during both periods (pthyroid equivalent doses by inhalation were estimated as 2.7 and 86.0 mSv, respectively, for Namie group, and 4.2 and 17.2 mSv, respectively, for Minamisoma group, 0.1 and 1.0 mSv, respectively, for Tomioka/Okuma/Futaba/Naraha group, and 0.2 and 2.1 mSv, respectively, for the other group. During 15- 17 March period, 50 and 95 percentiles of thyroid equivalent doses by inhalation were 0.8 and 15.7 mSv, respectively, for Namie group, and 1.6 and 8.4 mSv, respectively, for Minamisoma group, 0.2 and 13.2 mSv, respectively, for Tomioka/Okuma/Futaba/Naraha group, and 1.2 and 12.7 mSv, respectively, for the other group. It was indicated that inhalation dose was generally higher in Namie and Minamisoma groups during 12-14 March than those during 15-17 March might reflect different self-protective behavior to radioactive plumes from other groups.
Directory of Open Access Journals (Sweden)
Bizhong Xia
2017-08-01
Full Text Available Accurate state of charge (SOC estimation can prolong lithium-ion battery life and improve its performance in practice. This paper proposes a new method for SOC estimation. The second-order resistor-capacitor (2RC equivalent circuit model (ECM is applied to describe the dynamic behavior of lithium-ion battery on deriving state space equations. A novel method for SOC estimation is then presented. This method does not require any matrix calculation, so the computation cost can be very low, making it more suitable for hardware implementation. The Federal Urban Driving Schedule (FUDS, The New European Driving Cycle (NEDC, and the West Virginia Suburban Driving Schedule (WVUSUB experiments are carried to evaluate the performance of the proposed method. Experimental results show that the SOC estimation error can converge to 3% error boundary within 30 seconds when the initial SOC estimation error is 20%, and the proposed method can maintain an estimation error less than 3% with 1% voltage noise and 5% current noise. Further, the proposed method has excellent robustness against parameter disturbance. Also, it has higher estimation accuracy than the extended Kalman filter (EKF, but with decreased hardware requirements and faster convergence rate.
Garcia-Martinez, P.; Montes, P.; Schuster, E.
2017-10-01
The feasibility of controlling the q-profile using closed-loop controllers designed from first-principles-driven control-oriented models has been demonstrated in tokamaks like DIII-D. These control-oriented models typically use the magnetic diffusion equation for the poloidal magnetic flux profile evolution, combined with simplified models for other plasma quantities such as the electron density, the electron temperature, and the noninductive current-drives. The magnetic diffusion equation is expressed in flux coordinates thus requiring several geometric profiles that depend on the underlying MHD equilibrium of the plasma. In this work, a self-consistent method to improve the estimation of the MHD equilibrium and the required geometric profiles is proposed. The method combines a two-dimensional linear model, that takes into account the geometry of the flux surfaces, with a one-dimensional non-linear model that incorporates the evolution of the magnetic profiles resulting in a robust and fast strategy for MHD equilibrium estimation. Supported by the US DOE under DE-SC0010537, DE-SC0010661, and the Fulbright-CONICET scholar program.
Fernández, E N; Legarra, A; Martínez, R; Sánchez, J P; Baselga, M
2017-06-01
Inbreeding generates covariances between additive and dominance effects (breeding values and dominance deviations). In this work, we developed and applied models for estimation of dominance and additive genetic variances and their covariance, a model that we call "full dominance," from pedigree and phenotypic data. Estimates with this model such as presented here are very scarce both in livestock and in wild genetics. First, we estimated pedigree-based condensed probabilities of identity using recursion. Second, we developed an equivalent linear model in which variance components can be estimated using closed-form algorithms such as REML or Gibbs sampling and existing software. Third, we present a new method to refer the estimated variance components to meaningful parameters in a particular population, i.e., final partially inbred generations as opposed to outbred base populations. We applied these developments to three closed rabbit lines (A, V and H) selected for number of weaned at the Polytechnic University of Valencia. Pedigree and phenotypes are complete and span 43, 39 and 14 generations, respectively. Estimates of broad-sense heritability are 0.07, 0.07 and 0.05 at the base versus 0.07, 0.07 and 0.09 in the final generations. Narrow-sense heritability estimates are 0.06, 0.06 and 0.02 at the base versus 0.04, 0.04 and 0.01 at the final generations. There is also a reduction in the genotypic variance due to the negative additive-dominance correlation. Thus, the contribution of dominance variation is fairly large and increases with inbreeding and (over)compensates for the loss in additive variation. In addition, estimates of the additive-dominance correlation are -0.37, -0.31 and 0.00, in agreement with the few published estimates and theoretical considerations. © 2017 Blackwell Verlag GmbH.
Jones, Bleddyn; Cominos, Matilda; Dale, Roger G
2003-03-01
To investigate the potential for mathematic modeling in the assessment of symptom relief in palliative radiotherapy and cytotoxic chemotherapy. The linear quadratic model of radiation effect with the overall treatment time and the daily dose equivalent of repopulation is modified to include the regrowth time after completion of therapy. The predicted times to restore the original tumor volumes after treatment are dependent on the biological effective dose (BED) delivered and the repopulation parameter (K); it is also possible to estimate K values from analysis of palliative treatment response durations. Hypofractionated radiotherapy given at a low total dose may produce long symptom relief in slow-growing tumors because of their low alpha/beta ratios (which confer high fraction sensitivity) and their slow regrowth rates. Cancers that have high alpha/beta ratios (which confer low fraction sensitivity), and that are expected to repopulate rapidly during therapy, are predicted to have short durations of symptom control. The BED concept can be used to estimate the equivalent dose of radiotherapy that will achieve the same duration of symptom relief as palliative chemotherapy. Relatively simple radiobiologic modeling can be used to guide decision-making regarding the choice of the most appropriate palliative schedules and has important implications in the design of radiotherapy or chemotherapy clinical trials. The methods described provide a rationalization for treatment selection in a wide variety of tumors.
Kingni, S. T.; Jafari, S.; Simo, H.; Woafo, P.
2014-05-01
This paper proposes a three-dimensional chaotic autonomous system with only one stable equilibrium. This system belongs to a newly introduced category of chaotic systems with hidden attractors. The nonlinear dynamics of the proposed chaotic system is described through numerical simulations which include phase portraits, bifurcation diagrams and new cost function for parameter estimation of chaotic flows. The coexistence of a stable equilibrium point with a strange attractor is found in the proposed system for specific parameters values. The physical existence of the chaotic behavior found in the proposed system is verified by using the Orcard-PSpice software. A good qualitative agreement is shown between the simulations and the experimental results. Based on the Routh-Hurwitz conditions and for a specific choice of linear controllers, it is shown that the proposed chaotic system is controlled to its equilibrium point. Chaos synchronization of an identical proposed system is achieved by using the unidirectional linear and nonlinear error feedback coupling. Finally, the fractional-order form of the proposed system is studied by using the stability theory of fractional-order systems and numerical simulations. A necessary condition for the commensurate fractional order of this system to remain chaotic is obtained. It is found that chaos exists in this system with order less than three.
Directory of Open Access Journals (Sweden)
Hui Li
2017-01-01
Full Text Available Snow depth and Snow Water Equivalence (SWE are important parameters for hydrological applications. In this application, a theoretical method of snow depth estimation with repeat-pass InSAR measurements was proposed, and a preliminary sensitivity analysis of snow phase changes versus the incident angle and snow density was developed. Moreover, the snow density and incident angle parameters were analyzed and calibrated, and the local incident angle was used as a substitute for the satellite incident angle to improve the snow depth estimation. From the results, the coherence images showed that a high degree of coherence can be found for dry snow, and, apart from the effect of snow, land use/cover change due to a long temporal baseline and geometric distortion due to the rugged terrain were the main constraints for InSAR technique to measure snow depth and SWE in this area. The result of snow depth estimation between July 2008 and February 2009 demonstrated that the average snow depth was about 20 cm, which was consistent with the field survey results. The areal coverage of snow distribution estimated from the snow depth and SWE results was consistent with snow cover obtained from HJ-1A CCD optical data at the same time.
Nejad, S.; Gladwin, D. T.; Stone, D. A.
2016-06-01
This paper presents a systematic review for the most commonly used lumped-parameter equivalent circuit model structures in lithium-ion battery energy storage applications. These models include the Combined model, Rint model, two hysteresis models, Randles' model, a modified Randles' model and two resistor-capacitor (RC) network models with and without hysteresis included. Two variations of the lithium-ion cell chemistry, namely the lithium-ion iron phosphate (LiFePO4) and lithium nickel-manganese-cobalt oxide (LiNMC) are used for testing purposes. The model parameters and states are recursively estimated using a nonlinear system identification technique based on the dual Extended Kalman Filter (dual-EKF) algorithm. The dynamic performance of the model structures are verified using the results obtained from a self-designed pulsed-current test and an electric vehicle (EV) drive cycle based on the New European Drive Cycle (NEDC) profile over a range of operating temperatures. Analysis on the ten model structures are conducted with respect to state-of-charge (SOC) and state-of-power (SOP) estimation with erroneous initial conditions. Comparatively, both RC model structures provide the best dynamic performance, with an outstanding SOC estimation accuracy. For those cell chemistries with large inherent hysteresis levels (e.g. LiFePO4), the RC model with only one time constant is combined with a dynamic hysteresis model to further enhance the performance of the SOC estimator.
Schoer, Karl; Wood, Richard; Arto, Iñaki; Weinzettel, Jan
2013-12-17
The mass of material consumed by a population has become a useful proxy for measuring environmental pressure. The "raw material equivalents" (RME) metric of material consumption addresses the issue of including the full supply chain (including imports) when calculating national or product level material impacts. The RME calculation suffers from data availability, however, as quantitative data on production practices along the full supply chain (in different regions) is required. Hence, the RME is currently being estimated by three main approaches: (1) assuming domestic technology in foreign economies, (2) utilizing region-specific life-cycle inventories (in a hybrid framework), and (3) utilizing multi-regional input-output (MRIO) analysis to explicitly cover all regions of the supply chain. While the first approach has been shown to give inaccurate results, this paper focuses on the benefits and costs of the latter two approaches. We analyze results from two key (MRIO and hybrid) projects modeling raw material equivalents, adjusting the models in a stepwise manner in order to quantify the effects of individual conceptual elements. We attempt to isolate the MRIO gap, which denotes the quantitative impact of calculating the RME of imports by an MRIO approach instead of the hybrid model, focusing on the RME of EU external trade imports. While, the models give quantitatively similar results, differences become more pronounced when tracking more detailed material flows. We assess the advantages and disadvantages of the two approaches and look forward to ways to further harmonize data and approaches.
Chui, Tina Tsz-Ting; Lee, Wen-Chung
2014-01-01
Many diseases result from the interactions between genes and the environment. An efficient method has been proposed for a case-control study to estimate the genetic and environmental main effects and their interactions, which exploits the assumptions of gene-environment independence and Hardy-Weinberg equilibrium. To estimate the absolute and relative risks, one needs to resort to an alternative design: the case-base study. In this paper, the authors show how to analyze a case-base study under the above dual assumptions. This approach is based on a conditional logistic regression of case-counterfactual controls matched data. It can be easily fitted with readily available statistical packages. When the dual assumptions are met, the method is approximately unbiased and has adequate coverage probabilities for confidence intervals. It also results in smaller variances and shorter confidence intervals as compared with a previous method for a case-base study which imposes neither assumption.
Moteabbed, Maryam; Geyer, Amy; Drenkhahn, Robert; Bolch, Wesley E.; Paganetti, Harald
2012-01-01
Secondary neutron fluence created during proton therapy can be a significant source of radiation exposure in organs distant from the treatment site, especially in pediatric patients. Various published studies have used computational phantoms to estimate neutron equivalent doses in proton therapy. In these simulations, whole-body patient representations were applied considering either generic whole-body phantoms or generic age- and gender-dependent phantoms. No studies to date have reported using patient-specific geometry information. The purpose of this study was to estimate the effects of patient-phantom matching when using computational pediatric phantoms. To achieve this goal, three sets of phantoms, including different ages and genders, were compared to the patients’ whole-body CT. These sets consisted of pediatric age-specific reference, age-adjusted reference and anatomically sculpted phantoms. The neutron equivalent dose for a subset of out-of-field organs was calculated using the GEANT4 Monte Carlo toolkit, where proton fields were used to irradiate the cranium and the spine of all phantoms and the CT-segmented patient models. The maximum neutron equivalent dose per treatment absorbed dose was calculated and found to be on the order of 0 to 5 mSv Gy-1. The relative dose difference between each phantom and their respective CT-segmented patient model for most organs showed a dependence on how close the phantom and patient heights were matched. The weight matching was found to have much smaller impact on the dose accuracy except for very heavy patients. Analysis of relative dose difference with respect to height difference suggested that phantom sculpting has a positive effect in terms of dose accuracy as long as the patient is close to the 50th percentile height and weight. Otherwise, the benefit of sculpting was masked by inherent uncertainties, i.e. variations in organ shapes, sizes and locations. Other sources of uncertainty included errors associated
Ismail, M.S.
2014-01-01
We introduce a new concept which extends von Neumann and Morgenstern's maximin strategy solution by incorporating `individual rationality' of the players. Maximin equilibrium, extending Nash's value approach, is based on the evaluation of the strategic uncertainty of the whole game. We show that
Directory of Open Access Journals (Sweden)
E. E. Stigter
2017-07-01
Full Text Available Snow is an important component of water storage in the Himalayas. Previous snowmelt studies in the Himalayas have predominantly relied on remotely sensed snow cover. However, snow cover data provide no direct information on the actual amount of water stored in a snowpack, i.e., the snow water equivalent (SWE. Therefore, in this study remotely sensed snow cover was combined with in situ observations and a modified version of the seNorge snow model to estimate (climate sensitivity of SWE and snowmelt runoff in the Langtang catchment in Nepal. Snow cover data from Landsat 8 and the MOD10A2 snow cover product were validated with in situ snow cover observations provided by surface temperature and snow depth measurements resulting in classification accuracies of 85.7 and 83.1 % respectively. Optimal model parameter values were obtained through data assimilation of MOD10A2 snow maps and snow depth measurements using an ensemble Kalman filter (EnKF. Independent validations of simulated snow depth and snow cover with observations show improvement after data assimilation compared to simulations without data assimilation. The approach of modeling snow depth in a Kalman filter framework allows for data-constrained estimation of snow depth rather than snow cover alone, and this has great potential for future studies in complex terrain, especially in the Himalayas. Climate sensitivity tests with the optimized snow model revealed that snowmelt runoff increases in winter and the early melt season (December to May and decreases during the late melt season (June to September as a result of the earlier onset of snowmelt due to increasing temperature. At high elevation a decrease in SWE due to higher air temperature is (partly compensated by an increase in precipitation, which emphasizes the need for accurate predictions on the changes in the spatial distribution of precipitation along with changes in temperature.
Deeb, E. J.; Marshall, H. P.; Painter, T. H.; Marks, D. G.; Hedrick, A. R.; Havens, S.; Forster, R. R.; Siqueira, P.
2016-12-01
The interferometric approach to estimating snow water equivalent (SWE) leverages the fact that at relatively low frequencies ( 1 GHz, L-Band), differences in snow microstructure and layering do not significantly affect the radar backscatter of dry snow. At these frequencies, the main contribution of the radar backscatter is the snow/ground interface, and the difference in the timing of the radar propagation through the snowpack is controlled by snow depth, density and liquid water content. While engineering limitations prevent direct measurement of absolute radar travel-time, interferometric phase shift between acquisitions can be used to monitor changes in radar travel-time, caused by changes in snow properties. PALSAR-2 is a L-Band synthetic aperture radar (SAR) aboard the Japan Aerospace Exploration Agency's (JAXA) ALOS-2 satellite. Launched in 2014, PALSAR-2 interferometric pairs geographically and temporally overlap data collected by the NASA/JPL Airborne Snow Observatory (ASO) which provides spatial distribution of snow depths across basins (e.g. Tuolumne, CA and Grand Mesa, CO) identified as contributing significantly to NASA's multi-year airborne SnowEx campaign. As part of ASO's operational requirements, a spatially distributed energy balance snow model (iSnobal) is run over these domains estimating density (and other snow properties) and providing SWE products for water resource managers as well as other cryospheric science applications. This effort identifies PALSAR-2 satellite pairs closely coincident with ASO collections, processes interferometric products of coherence and phase change, and compares these results with the spatially distributed snow depths from ASO and modeled snow densities from iSnobal. Moreover, for satellite acquisitions not temporally matching the ASO collections, the modeled snow properties (depths and densities) from iSnobal are used for comparison with interferometric estimates of SWE. The integration of ground measurements
Wu, Qi; Sun, Baozhu; Wang, Shuqin; Zhao, Lianying; Qi, Feng
2013-01-01
The present paper proposes a new approach for fitting the plasma effect-site equilibrium rate constant (Ke0) of propofol to satisfy the condition that the effect-site concentration (Ce) is equal at the time of loss of consciousness (LOC) and recovery of consciousness (ROC). Forty patients receiving intravenous anesthesia were divided into 4 groups and injected propofol 1.4, 1.6, 1.8, or 2 mg/kg at 1,200 mL/h. Durations from the start of injection to LOC and to ROC were recorded. LOC and ROC were defined as an observer's assessment of alertness and sedation scale change from 3 to 2 and from 2 to 3, respectively. Software utilizing bisection method iteration algorithms was built. Then, Ke0 satisfying the CeLOC=CeROC condition was estimated. The accuracy of the Ke0 estimated by our method was compared with the Diprifusor TCI Pump built-in Ke0 (0.26 min(-1)), and the Orchestra Workstation built-in Ke0 (1.21 min(-1)) in another group of 21 patients who were injected propofol 1.4 to 2 mg/kg. Our results show that the population Ke0 of propofol was 0.53 ± 0.18 min(-1). The regression equation for adjustment by dose (mg/kg) and age was Ke0=1.42-0.30 × dose-0.0074 × age. Only Ke0 adjusted by dose and age achieved the level of accuracy required for clinical applications. We conclude that the Ke0 estimated based on clinical signs and the two-point fitting method significantly improved the ability of CeLOC to predict CeROC. However, only the Ke0 adjusted by dose and age and not a fixed Ke0 value can meet clinical requirements of accuracy.
Tarafa, Pedro J; Matthews, Michael A
2010-11-25
It is known that the commercial surfactant Dehypon® Ls-54 is soluble in supercritical CO(2) and that it enables formation of water-in-CO(2) microemulsions. In this work we observed phase equilibrium for the Ls-54/CO(2) and Ls-54/water/CO(2) systems in the liquid CO(2) region, from 278.15 - 298.15 K. In addition, the Peng-Robinson equation of state (PREOS) was used to model the phase behavior of Ls-54/CO(2) binary system as well as to estimate water solubilities in CO(2). Ls-54 in CO(2) can have solubilities as high as 0.086 M at 278.15 K and 15.2 MPa. The stability of the microemulsion decreases with increasing concentration of water, and lower temperatures favor increased solubility of water into the one-phase microemulsion. The PREOS model showed satisfactory agreement with the experimental data for both Ls-54/CO(2) and water/CO(2) systems.
Oliveira, Mário J
2013-01-01
This textbook provides an exposition of equilibrium thermodynamics and its applications to several areas of physics with particular attention to phase transitions and critical phenomena. The applications include several areas of condensed matter physics and include also a chapter on thermochemistry. Phase transitions and critical phenomena are treated according to the modern development of the field, based on the ideas of universality and on the Widom scaling theory. For each topic, a mean-field or Landau theory is presented to describe qualitatively the phase transitions. These theories include the van der Waals theory of the liquid-vapor transition, the Hildebrand-Heitler theory of regular mixtures, the Griffiths-Landau theory for multicritical points in multicomponent systems, the Bragg-Williams theory of order-disorder in alloys, the Weiss theory of ferromagnetism, the Néel theory of antiferromagnetism, the Devonshire theory for ferroelectrics and Landau-de Gennes theory of liquid crystals. This textbo...
de Oliveira, Mário J
2017-01-01
This textbook provides an exposition of equilibrium thermodynamics and its applications to several areas of physics with particular attention to phase transitions and critical phenomena. The applications include several areas of condensed matter physics and include also a chapter on thermochemistry. Phase transitions and critical phenomena are treated according to the modern development of the field, based on the ideas of universality and on the Widom scaling theory. For each topic, a mean-field or Landau theory is presented to describe qualitatively the phase transitions. These theories include the van der Waals theory of the liquid-vapor transition, the Hildebrand-Heitler theory of regular mixtures, the Griffiths-Landau theory for multicritical points in multicomponent systems, the Bragg-Williams theory of order-disorder in alloys, the Weiss theory of ferromagnetism, the Néel theory of antiferromagnetism, the Devonshire theory for ferroelectrics and Landau-de Gennes theory of liquid crystals. This new edit...
Lopez-Teros, Veronica; Ford, Jennifer Lynn; Green, Michael H; Tang, Guangwen; Grusak, Michael A; Quihui-Cota, Luis; Muzhingi, Tawanda; Paz-Cassini, Mariela; Astiazaran-Garcia, Humberto
2017-09-20
Background: Worldwide, an estimated 250 million children <5 y old are vitamin A (VA) deficient. In Mexico, despite ongoing efforts to reduce VA deficiency, it remains an important public health problem; thus, food-based interventions that increase the availability and consumption of provitamin A-rich foods should be considered.Objective: The objectives were to assess the VA equivalence of (2)H-labeled Moringa oleifera (MO) leaves and to estimate both total body stores (TBS) of VA and plasma retinol kinetics in young Mexican children.Methods: β-Carotene was intrinsically labeled by growing MO plants in a (2)H2O nutrient solution. Fifteen well-nourished children (17-35 mo old) consumed puréed MO leaves (1 mg β-carotene) and a reference dose of [(13)C10]retinyl acetate (1 mg) in oil. Blood (2 samples/child) was collected 10 times (2 or 3 children each time) over 35 d. The bioefficacy of MO leaves was calculated from areas under the composite "super-child" plasma isotope response curves, and MO VA equivalence was estimated through the use of these values; a compartmental model was developed to predict VA TBS and retinol kinetics through the use of composite plasma [(13)C10]retinol data. TBS were also estimated with isotope dilution.Results: The relative bioefficacy of β-carotene retinol activity equivalents from MO was 28%; VA equivalence was 3.3:1 by weight (0.56 μmol retinol:1 μmol β-carotene). Kinetics of plasma retinol indicate more rapid plasma appearance and turnover and more extensive recycling in these children than are observed in adults. Model-predicted mean TBS (823 μmol) was similar to values predicted using a retinol isotope dilution equation applied to data from 3 to 6 d after dosing (mean ± SD: 832 ± 176 μmol; n = 7).Conclusions: The super-child approach can be used to estimate population carotenoid bioefficacy and VA equivalence, VA status, and parameters of retinol metabolism from a composite data set. Our results provide initial estimates
Ross, H.A.; Meuleman, E.J.H.; Sweep, C.G.J.
2005-01-01
An algorithm was developed to evaluate equilibrium constants for testosterone (Te) and sex hormone-binding globulin (SHBG) or albumin from serum free testosterone (FTe) measurements performed in a panel of 30 healthy elderly men by means of a near-reference method, i.e., symmetric dialysis (affinity
Testing the Hardy-Weinberg equilibrium in the HLA system.
Eguchi, S; Matsuura, M
1990-06-01
A new method of testing the Hardy-Weinberg equilibrium in the human leukocyte antigen (HLA) system is proposed and applied to real data. The derivation is based on the maximum likelihood method and closely related to standard regression theory. The test statistic has a closed representation of residual sum of squares by a projection mapping of data onto the estimated regression plane. Under the Hardy-Weinberg law the noniterative estimates for the gene frequencies are suggested by the use of the projection mapping. The test statistic and gene frequency estimates are shown to be asymptotically equivalent to the maximum likelihood method and to be more efficient than the other suggested test statistic when there are more than two identified alleles.
Abo-Elmagd, M; Sadek, A M
2014-12-01
Can and Bare method is a widely used passive method for measuring the equilibrium factor F through the determination of the track density ratio between bare (D) and filtered (Do) detectors. The dimensions of the used diffusion chamber are altering the deposition ratios of Po-isotopes on the chamber walls as well as the ratios of the existing alpha emitters in air. Then the measured filtered track density and therefore the resultant equilibrium factor is changed according to the diffusion chamber dimensions. For this reason, high uncertainty was expected in the measured F using different diffusion chambers. In the present work, F is derived as a function of both track density ratio (D/Do) and the dimensions of the used diffusion chambers (its volume to the total internal surface area; V/A). The accuracy of the derived formula was verified using the black-box modeling technique via the MATLAB System identification toolbox. The results show that the uncertainty of the calculated F by using the derived formula of F (D/Do, V/A) is only 5%. The obtained uncertainty ensures the quality of the derived function to calculate F using diffusion chambers with wide range of dimensions. Copyright © 2014 Elsevier Ltd. All rights reserved.
Schlosser, Paul M; Lilly, Patrick D; Conolly, Rory B; Janszen, Derek B; Kimbell, Julie S
2003-06-01
Formaldehyde induced squamous-cell carcinomas in the nasal passages of F344 rats in two inhalation bioassays at exposure levels of 6 ppm and above. Increases in rates of cell proliferation were measured by T. M. Monticello and colleagues at exposure levels of 0.7 ppm and above in the same tissues from which tumors arose. A risk assessment for formaldehyde was conducted at the CIIT Centers for Health Research, in collaboration with investigators from Toxicological Excellence in Risk Assessment (TERA) and the U.S. Environmental Protection Agency (U.S. EPA) in 1999. Two methods for dose-response assessment were used: a full biologically based modeling approach and a statistically oriented analysis by benchmark dose (BMD) method. This article presents the later approach, the purpose of which is to combine BMD and pharmacokinetic modeling to estimate human cancer risks from formaldehyde exposure. BMD analysis was used to identify points of departure (exposure levels) for low-dose extrapolation in rats for both tumor and the cell proliferation endpoints. The benchmark concentrations for induced cell proliferation were lower than for tumors. These concentrations were extrapolated to humans using two mechanistic models. One model used computational fluid dynamics (CFD) alone to determine rates of delivery of inhaled formaldehyde to the nasal lining. The second model combined the CFD method with a pharmacokinetic model to predict tissue dose with formaldehyde-induced DNA-protein cross-links (DPX) as a dose metric. Both extrapolation methods gave similar results, and the predicted cancer risk in humans at low exposure levels was found to be similar to that from a risk assessment conducted by the U.S. EPA in 1991. Use of the mechanistically based extrapolation models lends greater certainty to these risk estimates than previous approaches and also identifies the uncertainty in the measured dose-response relationship for cell proliferation at low exposure levels, the dose
Ion exchange equilibrium constants
Marcus, Y
2013-01-01
Ion Exchange Equilibrium Constants focuses on the test-compilation of equilibrium constants for ion exchange reactions. The book first underscores the scope of the compilation, equilibrium constants, symbols used, and arrangement of the table. The manuscript then presents the table of equilibrium constants, including polystyrene sulfonate cation exchanger, polyacrylate cation exchanger, polymethacrylate cation exchanger, polysterene phosphate cation exchanger, and zirconium phosphate cation exchanger. The text highlights zirconium oxide anion exchanger, zeolite type 13Y cation exchanger, and
Quantity Constrained General Equilibrium
Babenko, R.; Talman, A.J.J.
2006-01-01
In a standard general equilibrium model it is assumed that there are no price restrictions and that prices adjust infinitely fast to their equilibrium values.In case of price restrictions a general equilibrium may not exist and rationing on net demands or supplies is needed to clear the markets.In
Bokma, Folmer
2008-11-01
Algorithms are presented to simultaneously estimate probabilities of speciation and extinction, rates of anagenetic and cladogenetic phenotypic evolution, as well as ancestral character states, from a complete ultrametric species-level phylogeny with dates assigned to all bifurcations and one or more phenotypes in three or more extant species, using Metropolis-Hastings Markov Chain Monte Carlo sampling. The algorithms also estimate missing phenotypes of extant species and numbers of speciation events that occurred on all branches of the phylogeny. The algorithms are discussed and their performance is evaluated using simulated data. That evaluation shows that precise estimation of rates of evolution of one or a few phenotypes requires large phylogenies. Estimation accuracy improves with the number of species on the phylogeny.
Energy Technology Data Exchange (ETDEWEB)
Kim, Y; Waldron, T; Pennington, E [University Of Iowa, College of Medicine, Iowa City, IA (United States)
2016-06-15
Purpose: To test the radiobiological impact of hypofractionated choroidal melanoma brachytherapy, we calculated single fraction equivalent doses (SFED) of the tumor that equivalent to 85 Gy of I125-BT for 20 patients. Corresponding organs-at-risks (OARs) doses were estimated. Methods: Twenty patients treated with I125-BT were retrospectively examined. The tumor SFED values were calculated from tumor BED using a conventional linear-quadratic (L-Q) model and an universal survival curve (USC). The opposite retina (α/β = 2.58), macula (2.58), optic disc (1.75), and lens (1.2) were examined. The % doses of OARs over tumor doses were assumed to be the same as for a single fraction delivery. The OAR SFED values were converted into BED and equivalent dose in 2 Gy fraction (EQD2) by using both L-Q and USC models, then compared to I125-BT. Results: The USC-based BED and EQD2 doses of the macula, optic disc, and the lens were on average 118 ± 46% (p < 0.0527), 126 ± 43% (p < 0.0354), and 112 ± 32% (p < 0.0265) higher than those of I125-BT, respectively. The BED and EQD2 doses of the opposite retina were 52 ± 9% lower than I125-BT. The tumor SFED values were 25.2 ± 3.3 Gy and 29.1 ± 2.5 Gy when using USC and LQ models which can be delivered within 1 hour. All BED and EQD2 values using L-Q model were significantly larger when compared to the USC model (p < 0.0274) due to its large single fraction size (> 14 Gy). Conclusion: The estimated single fraction doses were feasible to be delivered within 1 hour using a high dose rate source such as electronic brachytherapy (eBT). However, the estimated OAR doses using eBT were 112 ∼ 118% higher than when using the I125-BT technique. Continued exploration of alternative dose rate or fractionation schedules should be followed.
Energy Technology Data Exchange (ETDEWEB)
Rucker, G
2007-05-01
Soils at waste sites must be evaluated for the potential of residual soil contamination to leach and migrate to the groundwater beneath the disposal area. If migration to the aquifer occurs, contaminants can travel vast distances and contaminate drinking water wells, thus exposing human receptors to harmful levels of toxins and carcinogens. To prevent groundwater contamination, a contaminant fate and transport analysis is necessary to assess the migration potential of residual soil contaminates. This type of migration analysis is usually performed using a vadose zone model to account for complex geotechnical and chemical variables including: contaminant decay, infiltration rate, soil properties, vadose zone thickness, and chemical behavior. The distinct advantage of using a complex model is that less restrictive, but still protective, soil threshold levels may be determined avoiding the unnecessary and costly remediation of marginally contaminated soils. However, the disadvantage of such modeling is the additional cost for data collection and labor required to apply these models. In order to allay these higher costs and to achieve a less restrictive but still protective clean-up level, a multiple contaminant and multi layered soil column equilibrium partitioning model was developed which is faster, simpler and less expensive to use.
Tanzania’s Equilibrium Real Exchange Rate
Niko A Hobdari
2008-01-01
Tanzania's real effective exchange rate (REER) has depreciated sharply since end-2000, reversing the appreciation that took place in the second half of the 1990s. Single-country and panel data estimates, and the external sustainability approach, suggest that Tanzania's REER is currently modestly undervalued relative to its estimated equilibrium level. Looking forward, a modest trend appreciation of the equilibrium REER is expected, consistent with continued high GDP growth and an expected rec...
Biomonitoring Equivalents for selenium.
Hays, Sean M; Macey, Kristin; Nong, Andy; Aylward, Lesa L
2014-10-01
Selenium is an essential nutrient for human health with a narrow range between essentiality and toxicity. Selenium is incorporated into several proteins that perform important functions in the body. With insufficient selenium intake, the most notable effect is Keshan disease, an endemic cardiomyopathy in children. Conversely, excessive selenium intake can result in selenosis, manifested as brittle nails and hair and gastro-intestinal disorders. As such, guidance values have been established to protect against both insufficient and excessive selenium exposures. Dietary Reference Intakes (DRIs) have been established as standard reference values for nutritional adequacy in North America. To protect against selenosis resulting from exposure to excessive amounts of selenium, several government and non-governmental agencies have established a range of guidance values. Exposure to selenium is primarily through the diet, but monitoring selenium intake is difficult. Biomonitoring is a useful means of assessing and monitoring selenium status for both insufficient and excessive exposures. However, to be able to interpret selenium biomonitoring data, levels associated with both DRIs and toxicity guidance values are required. Biomonitoring Equivalents (BEs) were developed for selenium in whole blood, plasma and urine. The BEs associated with assuring adequate selenium intake (Estimated Average Requirements - EAR) are 100, 80 and 10μg/L in whole blood, plasma and urine, respectively. The BEs associated with protection against selenosis range from 400 to 480μg/L in whole blood, 180-230μg/L in plasma, and 90-110μg/L in urine. These BE values can be used by both regulatory agencies and public health officials to interpret selenium biomonitoring data in a health risk context. Copyright © 2014 Elsevier Inc. All rights reserved.
Multimodal Network Equilibrium with Stochastic Travel Times
Directory of Open Access Journals (Sweden)
M. Meng
2014-01-01
Full Text Available The private car, unlike public traffic modes (e.g., subway, trolley running along dedicated track-ways, is invariably subject to various uncertainties resulting in travel time variation. A multimodal network equilibrium model is formulated that explicitly considers stochastic link capacity variability in the road network. The travel time of combined-mode trips is accumulated based on the concept of the mean excess travel time (METT which is a summation of estimated buffer time and tardy time. The problem is characterized by an equivalent VI (variational inequality formulation where the mode choice is expressed in a hierarchical logit structure. Specifically, the supernetwork theory and expansion technique are used herein to represent the multimodal transportation network, which completely represents the combined-mode trips as constituting multiple modes within a trip. The method of successive weighted average is adopted for problem solutions. The model and solution method are further applied to study the trip distribution and METT variations caused by the different levels of the road conditions. Results of numerical examples show that travelers prefer to choose the combined travel mode as road capacity decreases. Travelers with different attitudes towards risk are shown to exhibit significant differences when making travel choice decisions.
Brignole, Esteban Alberto
2013-01-01
Traditionally, the teaching of phase equilibria emphasizes the relationships between the thermodynamic variables of each phase in equilibrium rather than its engineering applications. This book changes the focus from the use of thermodynamics relationships to compute phase equilibria to the design and control of the phase conditions that a process needs. Phase Equilibrium Engineering presents a systematic study and application of phase equilibrium tools to the development of chemical processes. The thermodynamic modeling of mixtures for process development, synthesis, simulation, design and
Directory of Open Access Journals (Sweden)
Rafael Moreira Claro
2010-11-01
Full Text Available This study aims to estimate an adult-equivalent scale for calorie requirements and to determine the differences between adult-equivalent and per capita measurements of calorie availability in the Brazilian population. The study used data from the 2002-2003 Brazilian Household Budget Survey. The calorie requirement for a reference adult individual was based on the mean requirements for adult males and females (2,550kcal/day. The conversion factors were defined as the ratios between the calorie requirements for each age group and gender and that of the reference adult. The adult-equivalent calorie availability levels were higher than the per capita levels, with the largest differences in rural and low-income households. Differences in household calorie availability varied from 22kcal/day (households with adults and an adolescent to 428kcal/day (households with elderly individuals, thus showing that per capital measurements can underestimate the real calorie availability, since they overlook differences in household composition.Objetivou-se estimar uma escala adulto-equivalente de necessidade energética e determinar as diferenças entre medidas adulto-equivalente e per capita para disponibilidade energética da população brasileira. Utilizaram-se dados da Pesquisa de Orçamentos Familiares de 2002/2003. A necessidade energética de um indivíduo adulto de referência baseou-se na média das necessidades de homens e mulheres adultos (2.550kcal/dia. Os fatores de conversão foram definidos como a razão entre a necessidade energética de cada grupo de idade e sexo e aquela do adulto de referência. Os valores de disponibilidade de energia adulto-equivalente foram superiores aos per capita, sendo as maiores diferenças nos domicílios da área rural e de menor renda. As diferenças na disponibilidade energética domiciliar variavam entre 22kcal/dia (domicílio contendo adultos e adolescente e 428kcal/dia (domicílio onde residem idosos
Fractal Geometry of Equilibrium Payoffs in Discounted Supergames
Berg, Kimmo; Kitti, Mitri
2014-08-01
This paper examines the pure-strategy subgame-perfect equilibrium payoffs in discounted supergames with perfect monitoring. It is shown that the equilibrium payoffs can be identified as sub-self-affine sets or graph-directed iterated function systems. We propose a method to estimate the Hausdorff dimension of the equilibrium payoffs and relate it to the equilibrium paths and their graph presentation.
Experimental determination of thermodynamic equilibrium in biocatalytic transamination
DEFF Research Database (Denmark)
Tufvesson, Pär; Jensen, Jacob Skibsted; Kroutil, Wolfgang
2012-01-01
The equilibrium constant is a critical parameter for making rational design choices in biocatalytic transamination for the synthesis of chiral amines. However, very few reports are available in the scientific literature determining the equilibrium constant (K) for the transamination of ketones....... Various methods for determining (or estimating) equilibrium have previously been suggested, both experimental as well as computational (based on group contribution methods). However, none of these were found suitable for determining the equilibrium constant for the transamination of ketones. Therefore...
Beyond equilibrium climate sensitivity
Knutti, Reto; Rugenstein, Maria A. A.; Hegerl, Gabriele C.
2017-10-01
Equilibrium climate sensitivity characterizes the Earth's long-term global temperature response to increased atmospheric CO2 concentration. It has reached almost iconic status as the single number that describes how severe climate change will be. The consensus on the 'likely' range for climate sensitivity of 1.5 °C to 4.5 °C today is the same as given by Jule Charney in 1979, but now it is based on quantitative evidence from across the climate system and throughout climate history. The quest to constrain climate sensitivity has revealed important insights into the timescales of the climate system response, natural variability and limitations in observations and climate models, but also concerns about the simple concepts underlying climate sensitivity and radiative forcing, which opens avenues to better understand and constrain the climate response to forcing. Estimates of the transient climate response are better constrained by observed warming and are more relevant for predicting warming over the next decades. Newer metrics relating global warming directly to the total emitted CO2 show that in order to keep warming to within 2 °C, future CO2 emissions have to remain strongly limited, irrespective of climate sensitivity being at the high or low end.
Carbon Equivalent and Maximum Hardness
Haruyoshi, Suzuki; Head Office, Nippon Steel Corporation
1984-01-01
The accuracy of formulae for estimating the maximum hardness values of the HAZ from chemical composition and cooling time for welds in high strength steel is discussed and a new formula. NSC-S, is proposed which uses only C%, Pcm% and cooling time for the purpose of satisfactory accuracy. IIW CE and Ito-Bessyo Pcm carbon equivalent alone are not satisfactory in establishing Hmax values. The former is good only for slow cooling, t8/5 longer than 10 seconds, while the latter is good only for fa...
[Study on the maximum entropy principle and population genetic equilibrium].
Zhang, Hong-Li; Zhang, Hong-Yan
2006-03-01
A general mathematic model of population genetic equilibrium about one locus was constructed based on the maximum entropy principle by WANG Xiao-Long et al. They proved that the maximum solve of the model was just the frequency distribution that a population reached Hardy-Weinberg genetic equilibrium. It can suggest that a population reached Hardy-Weinberg genetic equilibrium when the genotype entropy of the population reached the maximal possible value, and that the frequency distribution of the maximum entropy was equivalent to the distribution of Hardy-Weinberg equilibrium law about one locus. They further assumed that the frequency distribution of the maximum entropy was equivalent to all genetic equilibrium distributions. This is incorrect, however. The frequency distribution of the maximum entropy was only equivalent to the distribution of Hardy-Weinberg equilibrium with respect to one locus or several limited loci. The case with regard to limited loci was proved in this paper. Finally we also discussed an example where the maximum entropy principle was not the equivalent of other genetic equilibria.
System equivalent model mixing
Klaassen, Steven W.B.; van der Seijs, M.V.; de Klerk, D.
2017-01-01
This paper introduces SEMM: a method based on Frequency Based Substructuring (FBS) techniques that enables the construction of hybrid dynamic models. With System Equivalent Model Mixing (SEMM) frequency based models, either of numerical or experimental nature, can be mixed to form a hybrid model.
Garcia-Escartin, Juan Carlos; Chamorro-Posada, Pedro
2011-01-01
Quantum algorithms and protocols are often presented as quantum circuits for a better understanding. We give a list of equivalence rules which can help in the analysis and design of quantum circuits. As example applications we study quantum teleportation and dense coding protocols in terms of a simple XOR swapping circuit and give an intuitive picture of a basic gate teleportation circuit.
Establishing Substantial Equivalence: Metabolomics
Beale, Michael H.; Ward, Jane L.; Baker, John M.
Modern ‘metabolomic’ methods allow us to compare levels of many structurally diverse compounds in an automated fashion across a large number of samples. This technology is ideally suited to screening of populations of plants, including trials where the aim is the determination of unintended effects introduced by GM. A number of metabolomic methods have been devised for the determination of substantial equivalence. We have developed a methodology, using [1H]-NMR fingerprinting, for metabolomic screening of plants and have applied it to the study of substantial equivalence of field-grown GM wheat. We describe here the principles and detail of that protocol as applied to the analysis of flour generated from field plots of wheat. Particular emphasis is given to the downstream data processing and comparison of spectra by multivariate analysis, from which conclusions regarding metabolome changes due to the GM can be assessed against the background of natural variation due to environment.
Directory of Open Access Journals (Sweden)
Katalin Martinás
2007-02-01
Full Text Available A microeconomic, agent based framework to dynamic economics is formulated in a materialist approach. An axiomatic foundation of a non-equilibrium microeconomics is outlined. Economic activity is modelled as transformation and transport of commodities (materials owned by the agents. Rate of transformations (production intensity, and the rate of transport (trade are defined by the agents. Economic decision rules are derived from the observed economic behaviour. The non-linear equations are solved numerically for a model economy. Numerical solutions for simple model economies suggest that the some of the results of general equilibrium economics are consequences only of the equilibrium hypothesis. We show that perfect competition of selfish agents does not guarantee the stability of economic equilibrium, but cooperativity is needed, too.
From equivalence to adaptation
Directory of Open Access Journals (Sweden)
Paulina Borowczyk
2009-01-01
Full Text Available The aim of this paper is to illustrate in which cases the translators use the adaptation when they are confronted with a term related to sociocultural aspects. We will discuss the notions of equivalence and adaptation and their limits in the translation. Some samples from Arte TV news and from the American film Shrek translated into Polish, German and French will be provided as a support for this article.
Directory of Open Access Journals (Sweden)
Nicolas Oury
2010-06-01
Full Text Available We present a reduction of the termination problem for a Turing machine (in the simplified form of the Post correspondence problem to the problem of determining whether a continuous-time Markov chain presented as a set of Kappa graph-rewriting rules has an equilibrium. It follows that the problem of whether a computable CTMC is dissipative (ie does not have an equilibrium is undecidable.
Equilibrium statistical mechanics
Mayer, J E
1968-01-01
The International Encyclopedia of Physical Chemistry and Chemical Physics, Volume 1: Equilibrium Statistical Mechanics covers the fundamental principles and the development of theoretical aspects of equilibrium statistical mechanics. Statistical mechanical is the study of the connection between the macroscopic behavior of bulk matter and the microscopic properties of its constituent atoms and molecules. This book contains eight chapters, and begins with a presentation of the master equation used for the calculation of the fundamental thermodynamic functions. The succeeding chapters highlight t
Directory of Open Access Journals (Sweden)
Yoshihiro Kudo
2016-01-01
Full Text Available Individual distribution constants (KD,A of picrate ion (Pic− and extraction constants (Kex± of NaPic by some crown ethers (L into benzene (Bz at 25°C were calculated from data reported previously. These constants were defined as KD,Pic=Pic-o/[Pic-] and Kex±=NaL+oPic-o/(Na+Lo[Pic-], respectively. Here, the subscript “o” denotes an organic (o phase and practically o = Bz. 15-Crown-5 ether (15C5, 18-crown-6 one (18C6, and their monobenzo (B derivatives (B15C5 and B18C6 were selected as L. Interfacial equilibrium-potential differences (Δϕeq at extraction were estimated at 298 K. A plot of logKex± versus -Δϕeq for the four L extraction systems gave a straight line with slope = 84 V−1. This slope was compared with those, reported before, of the dichloromethane (DCM, 1,2-dichloroethane (DCE, and nitrobenzene (NB extraction systems. The slopes of the regression lines were in the order NB < DCM ≤ DCE < Bz. Also, the individual distribution constants of the complex ion NaL+ and an ion-pair complex (NaL+Pic- into Bz phase were calculated from the above extraction data. At least, a comparison between these values suggests that Bz molecules mainly interact with NaL+ moiety of NaL+Pic-.
A century of Hardy-Weinberg equilibrium.
Mayo, Oliver
2008-06-01
Hardy-Weinberg equilibrium (HWE) is the state of the genotypic frequency of two alleles of one autosomal gene locus after one discrete generation of random mating in an indefinitely large population: if the alleles are A and a with frequencies p and q(=1-p), then the equilibrium gene frequencies are simply p and q and the equilibrium genotypic frequencies for AA, Aa and aa are p2, 2pq and q2. It was independently identified in 1908 by G. H. Hardy and W. Weinberg after earlier attempts by W. E. Castle and K. Pearson. Weinberg, well known for pioneering studies of twins, made many important contributions to genetics, especially human genetics. Existence of this equilibrium provides a reference point against which the effects of selection, linkage, mutation, inbreeding and chance can be detected and estimated. Its discovery marked the initiation of population genetics.
Equivalence principle and bound kinetic energy.
Hohensee, Michael A; Müller, Holger; Wiringa, R B
2013-10-11
We consider the role of the internal kinetic energy of bound systems of matter in tests of the Einstein equivalence principle. Using the gravitational sector of the standard model extension, we show that stringent limits on equivalence principle violations in antimatter can be indirectly obtained from tests using bound systems of normal matter. We estimate the bound kinetic energy of nucleons in a range of light atomic species using Green's function Monte Carlo calculations, and for heavier species using a Woods-Saxon model. We survey the sensitivities of existing and planned experimental tests of the equivalence principle, and report new constraints at the level of between a few parts in 10(6) and parts in 10(8) on violations of the equivalence principle for matter and antimatter.
Equilibrium fluctuation relations for voltage coupling in membrane proteins.
Kim, Ilsoo; Warshel, Arieh
2015-11-01
A general theoretical framework is developed to account for the effects of an external potential on the energetics of membrane proteins. The framework is based on the free energy relation between two (forward/backward) probability densities, which was recently generalized to non-equilibrium processes, culminating in the work-fluctuation theorem. Starting from the probability densities of the conformational states along the "voltage coupling" reaction coordinate, we investigate several interconnected free energy relations between these two conformational states, considering voltage activation of ion channels. The free energy difference between the two conformational states at zero (depolarization) membrane potential (i.e., known as the chemical component of free energy change in ion channels) is shown to be equivalent to the free energy difference between the two "equilibrium" (resting and activated) conformational states along the one-dimensional voltage couplin reaction coordinate. Furthermore, the requirement that the application of linear response approximation to the free energy functionals of voltage coupling should satisfy the general free energy relations, yields a novel closed-form expression for the gating charge in terms of other basic properties of ion channels. This connection is familiar in statistical mechanics, known as the equilibrium fluctuation-response relation. The theory is illustrated by considering the coupling of a unit charge to the external voltage in the two sites near the surface of membrane, representing the activated and resting states. This is done using a coarse-graining (CG) model of membrane proteins, which includes the membrane, the electrolytes and the electrodes. The CG model yields Marcus-type voltage dependent free energy parabolas for the response of the electrostatic environment (electrolytes etc.) to the transition from the initial to the final configuratinal states, leading to equilibrium free energy difference and free
Energy Technology Data Exchange (ETDEWEB)
Mazonakis, Michalis, E-mail: mazonak@med.uoc.gr; Damilakis, John [Department of Medical Physics, Faculty of Medicine, University of Crete, P.O. Box 2208, Iraklion, Crete 71003 (Greece); Varveris, Charalambos; Lyraraki, Efrossyni [Department of Radiotherapy and Oncology, University Hospital of Iraklion, Iraklion, Crete 71110 (Greece)
2015-11-15
Purpose: The aim of the current study was to (a) calculate the organ equivalent dose (OED) and (b) estimate the associated second cancer risk to partially in-field critical structures from adjuvant radiotherapy for stage I seminoma of the testis on the basis of three different nonlinear risk models. Methods: Three-dimensional plans were created for twelve patients who underwent a treatment planning computed tomography of the abdomen. The plans for irradiation of seminoma consisted of para-aortic anteroposterior and posteroanterior fields giving 20 Gy to the target site with 6 MV photons. The OED of stomach, colon, liver, pancreas, and kidneys, that were partially included in the treatment volume, was calculated using differential dose–volume histograms. The mechanistic, bell-shaped, and plateau models were employed for these calculations provided that organ-specific parameters were available for the subsequent assessment of the excess absolute risk (EAR) for second cancer development. The estimated organ-specific lifetime risks were compared with the respective nominal intrinsic probabilities for cancer induction. Results: The mean OED, which was calculated from the patients’ treatment plans, varied from 0.54 to 6.61 Gy by the partially in-field organ of interest and the model used for dosimetric calculations. The difference between the OED of liver derived from the mechanistic model with those from the bell-shaped and plateau models was less than 1.8%. An even smaller deviation of 1.0% was observed for colon. For the rest organs of interest, the differences between the OED values obtained by the examined models varied from 8.6% to 50.0%. The EAR for stomach, colon, liver, pancreas, and kidney cancer induction at an age of 70 yr because of treatment of a typical 39-yr-old individual was up to 4.24, 11.39, 0.91, 3.04, and 0.14 per 10 000 persons-yr, respectively. Patient’s irradiation was found to elevate the lifetime intrinsic risks by 8.3%–63.0% depending
Energy Technology Data Exchange (ETDEWEB)
Cooper, P.W.
1994-07-01
The term ``TNT Equivalence`` is used throughout the explosives and related industries to compare the effects of the output of a given explosive to that of TNT. This is done for technical design reasons in scaling calculation such as for the prediction of blast waves, craters, and structural response, and is also used as a basis for government regulations controlling the shipping, handling and storage of explosive materials, as well as for the siting and design of explosive facilities. TNT equivalence is determined experimentally by several different types of tests, the most common of which include: plate dent, ballistic mortar, trauzl, sand crush, and air blast. All of these tests do not necessarily measure the same output property of the sample explosive. As examples of this, some tests depend simply upon the CJ pressure, some depend upon the PV work in the CJ zone and in the Taylor wave behind the CJ plane, some are functions of the total work which includes that from secondary combustion in the air mixing region of the fireball and are acutely effected by the shape of the pressure-time profile of the wave. Some of the tests incorporate systematic errors which are not readily apparent, and which have a profound effect upon skewing the resultant data. Further, some of the tests produce different TNT Equivalents for the same explosive which are a function of the conditions at which the test is run. This paper describes the various tests used, discusses the results of each test and makes detailed commentary on what the test is actually measuring, how the results may be interpreted, and if and how these results can be predicted by first principals based calculations. Extensive data bases are referred to throughout the paper and used in examples for each point in the commentaries.
Equivalence, commensurability, value
DEFF Research Database (Denmark)
Albertsen, Niels
2017-01-01
Deriving value in Capital Marx uses three commensurability arguments (CA1-3). CA1 establishes equivalence in exchange as exchangeability with the same third commodity. CA2 establishes value as common denominator in commodities: embodied abstract labour. CA3 establishes value substance...... as commonality of labour: physiological labour. Tensions between these logics have permeated Marxist interpretations of value. Some have supported value as embodied labour (CA2, 3), others a monetary theory of value and value as ‘pure’ societal abstraction (ultimately CA1). They all are grounded in Marx....
Local Stellarator Equilibrium Model
Hudson, Stuart R.; Hegna, Chris C.; Lewandowski, Jerome W.
2000-10-01
Extensive calculations of ballooning and drift waves spectrums in asymmetric toroidal configurations (e.g. stellarators) to appreciate the role of magnetic geometry and profile variations are usually are usually prohibitive as the evaluation of the magneto-hydrodynamic (MHD) equilibrium is in itself a non-trivial problem. Although simple analytical MHD model equilibria do exist for tokamak configurations, their stellarator counterparts are usually crude or very approximate. In order to make more extensive stability calculations (of both ideal ballooning and drift-type modes), a technique for generating three-dimensional magneto-static equilibria, localized to a magnetic surface, has been developed. The technique allows one to easily manipulate various 3-D shaping and profile effects on a magnetic surface avoiding the need to recompute an entire three dimensional solution of the equilibrium. The model equilibrium has been implemented into existing ideal MHD ballooning and drift wave numerical codes. Marginal ballooning stability diagrams and drift wave calculations will be reported.
Beyond Equilibrium Thermodynamics
Öttinger, Hans Christian
2005-01-01
Beyond Equilibrium Thermodynamics fills a niche in the market by providing a comprehensive introduction to a new, emerging topic in the field. The importance of non-equilibrium thermodynamics is addressed in order to fully understand how a system works, whether it is in a biological system like the brain or a system that develops plastic. In order to fully grasp the subject, the book clearly explains the physical concepts and mathematics involved, as well as presenting problems and solutions; over 200 exercises and answers are included. Engineers, scientists, and applied mathematicians can all use the book to address their problems in modelling, calculating, and understanding dynamic responses of materials.
Establishing Substantial Equivalence: Proteomics
Lovegrove, Alison; Salt, Louise; Shewry, Peter R.
Wheat is a major crop in world agriculture and is consumed after processing into a range of food products. It is therefore of great importance to determine the consequences (intended and unintended) of transgenesis in wheat and whether genetically modified lines are substantially equivalent to those produced by conventional plant breeding. Proteomic analysis is one of several approaches which can be used to address these questions. Two-dimensional PAGE (2D PAGE) remains the most widely available method for proteomic analysis, but is notoriously difficult to reproduce between laboratories. We therefore describe methods which have been developed as standard operating procedures in our laboratory to ensure the reproducibility of proteomic analyses of wheat using 2D PAGE analysis of grain proteins.
Equilibrium shoreface profiles
DEFF Research Database (Denmark)
Aagaard, Troels; Hughes, Michael G
2017-01-01
Large-scale coastal behaviour models use the shoreface profile of equilibrium as a fundamental morphological unit that is translated in space to simulate coastal response to, for example, sea level oscillations and variability in sediment supply. Despite a longstanding focus on the shoreface prof...
On Quantum Microcanonical Equilibrium
Dorje C. Brody; Hook, Daniel W.; Hughston, Lane P.
2007-01-01
A quantum microcanonical postulate is proposed as a basis for the equilibrium properties of small quantum systems. Expressions for the corresponding density of states are derived, and are used to establish the existence of phase transitions for finite quantum systems. A grand microcanonical ensemble is introduced, which can be used to obtain new rigorous results in quantum statistical mechanics. Accepted version
On quantum microcanonical equilibrium
Energy Technology Data Exchange (ETDEWEB)
Brody, Dorje C [Department of Mathematics, Imperial College, London SW7 2BZ (United Kingdom); Hook, Daniel W [Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom); Hughston, Lane P [Department of Mathematics, King' s College London, The Strand, London WC2R 2LS (United Kingdom)
2007-05-15
A quantum microcanonical postulate is proposed as a basis for the equilibrium properties of small quantum systems. Expressions for the corresponding density of states are derived, and are used to establish the existence of phase transitions for finite quantum systems. A grand microcanonical ensemble is introduced, which can be used to obtain new rigorous results in quantum statistical mechanics.
Differential Equation of Equilibrium
African Journals Online (AJOL)
user
ABSTRACT. Analysis of underground circular cylindrical shell is carried out in this work. The forth order differential equation of equilibrium, comparable to that of beam on elastic foundation, was derived from static principles on the assumptions of P. L Pasternak. Laplace transformation was used to solve the governing ...
DEFF Research Database (Denmark)
Bollerslev, Tim; Sizova, Natalia; Tauchen, George
Stock market volatility clusters in time, carries a risk premium, is fractionally inte- grated, and exhibits asymmetric leverage effects relative to returns. This paper develops a first internally consistent equilibrium based explanation for these longstanding empirical facts. The model is cast...
Differential Equation of Equilibrium
African Journals Online (AJOL)
user
differential equation of equilibrium, comparable to that of beam on elastic foundation, was derived from static principles on the ... tedious and more time saving than the classical method in the solution of the aforementioned differential equation. ... silos, pipelines, bridge arches or wind turbine towers [3]. The objective of this ...
Microeconomics : Equilibrium and Efficiency
Ten Raa, T.
2013-01-01
Microeconomics: Equilibrium and Efficiency teaches how to apply microeconomic theory in an innovative, intuitive and concise way. Using real-world, empirical examples, this book not only covers the building blocks of the subject, but helps gain a broad understanding of microeconomic theory and
[Maximum entropy principle and population genetic equilibrium].
Wang, Xiao-Long; Yuan, Zhi-Fa; Guo, Man-Cai; Song, Shi-De; Zhang, Quan-Qi; Bao, Zhen-Min
2002-06-01
A general mathematic model of population genetic equilibrium was constructed based on the maximum entropy principle. We proved that the maximum entropy probability distribution was equivalent to the Hardy-Weinberg equilibrium law. A population reached genetic equilibrium when the genotype entropy of the population reached the maximal possible value. In information theory, the entropy or the information content is used to measure the uncertainty of a system. In population genetics, we can use entropy to measure the uncertainty of the genotype of a population. The agreement of the maximum entropy principle and the hardy-Weinberg equilibrium law indicated that random crossing is an irreversible process, which increases the genotype entropy of the population, while inbreeding and selection decrease the genotype entropy of the population. In animal or plant breeding, we often use selection and/or inbreeding to decrease the entropy of a population, and use intercrossing to increase the entropy of the population. In this point of view, breeding is actually regulating the entropy of population. By applying the basic principle of informatics in population genetics, we revealed the biological significance of the genotype entropy and demonstrated that we can work over population genetic problems with the principles and methods of informatics and cybernetics.
Emergent supersymmetry in local equilibrium systems
Gao, Ping; Liu, Hong
2018-01-01
Many physical processes we observe in nature involve variations of macroscopic quantities over spatial and temporal scales much larger than microscopic molecular collision scales and can be considered as in local thermal equilibrium. In this paper we show that any classical statistical system in local thermal equilibrium has an emergent supersymmetry at low energies. We use the framework of non-equilibrium effective field theory for quantum many-body systems defined on a closed time path contour and consider its classical limit. Unitarity of time evolution requires introducing anti-commuting degrees of freedom and BRST symmetry which survive in the classical limit. The local equilibrium is realized through a Z 2 dynamical KMS symmetry. We show that supersymmetry is equivalent to the combination of BRST and a specific consequence of the dynamical KMS symmetry, to which we refer as the special dynamical KMS condition. In particular, we prove a theorem stating that a system satisfying the special dynamical KMS condition is always supersymmetrizable. We discuss a number of examples explicitly, including model A for dynamical critical phenomena, a hydrodynamic theory of nonlinear diffusion, and fluctuating hydrodynamics for relativistic charged fluids.
Problems in equilibrium theory
Aliprantis, Charalambos D
1996-01-01
In studying General Equilibrium Theory the student must master first the theory and then apply it to solve problems. At the graduate level there is no book devoted exclusively to teaching problem solving. This book teaches for the first time the basic methods of proof and problem solving in General Equilibrium Theory. The problems cover the entire spectrum of difficulty; some are routine, some require a good grasp of the material involved, and some are exceptionally challenging. The book presents complete solutions to two hundred problems. In searching for the basic required techniques, the student will find a wealth of new material incorporated into the solutions. The student is challenged to produce solutions which are different from the ones presented in the book.
Analysis of sedimentation equilibrium distributions reflecting nonideal macromolecular associations.
Wills, Peter R.; Jacobsen, Michael P.; Winzor, Donald J.
2000-01-01
A rigorous statistical-mechanical approach is adopted to derive general quantitative expressions that allow for the effects of thermodynamic nonideality in equilibrium measurements reflecting interaction between dissimilar macromolecular reactants. An analytical procedure based on these expressions is then formulated for obtaining global estimates of equilibrium constants and the corresponding reference thermodynamic activities of the free reactants in each of several sedimentation equilibriu...
Equilibrium statistical mechanics
Jackson, E Atlee
2000-01-01
Ideal as an elementary introduction to equilibrium statistical mechanics, this volume covers both classical and quantum methodology for open and closed systems. Introductory chapters familiarize readers with probability and microscopic models of systems, while additional chapters describe the general derivation of the fundamental statistical mechanics relationships. The final chapter contains 16 sections, each dealing with a different application, ordered according to complexity, from classical through degenerate quantum statistical mechanics. Key features include an elementary introduction t
Equilibrium thermodynamics - Callen's postulational approach
Jongschaap, R.J.J.; Öttinger, Hans Christian
2001-01-01
In order to provide the background for nonequilibrium thermodynamics, we outline the fundamentals of equilibrium thermodynamics. Equilibrium thermodynamics must not only be obtained as a special case of any acceptable nonequilibrium generalization but, through its shining example, it also elucidates
Multi-period equilibrium/near-equilibrium in electricity markets based on locational marginal prices
Garcia Bertrand, Raquel
In this dissertation we propose an equilibrium procedure that coordinates the point of view of every market agent resulting in an equilibrium that simultaneously maximizes the independent objective of every market agent and satisfies network constraints. Therefore, the activities of the generating companies, consumers and an independent system operator are modeled: (1) The generating companies seek to maximize profits by specifying hourly step functions of productions and minimum selling prices, and bounds on productions. (2) The goals of the consumers are to maximize their economic utilities by specifying hourly step functions of demands and maximum buying prices, and bounds on demands. (3) The independent system operator then clears the market taking into account consistency conditions as well as capacity and line losses so as to achieve maximum social welfare. Then, we approach this equilibrium problem using complementarity theory in order to have the capability of imposing constraints on dual variables, i.e., on prices, such as minimum profit conditions for the generating units or maximum cost conditions for the consumers. In this way, given the form of the individual optimization problems, the Karush-Kuhn-Tucker conditions for the generating companies, the consumers and the independent system operator are both necessary and sufficient. The simultaneous solution to all these conditions constitutes a mixed linear complementarity problem. We include minimum profit constraints imposed by the units in the market equilibrium model. These constraints are added as additional constraints to the equivalent quadratic programming problem of the mixed linear complementarity problem previously described. For the sake of clarity, the proposed equilibrium or near-equilibrium is first developed for the particular case considering only one time period. Afterwards, we consider an equilibrium or near-equilibrium applied to a multi-period framework. This model embodies binary
Average inbreeding or equilibrium inbreeding?
Hedrick, P. W.
1986-01-01
The equilibrium inbreeding is always higher than the average inbreeding. For human populations with high inbreeding levels, the inbreeding equilibrium is more than 25% higher than the average inbreeding. Assuming no initial inbreeding in the population, the equilibrium inbreeding value is closely approached in 10 generations or less. A secondary effect of this higher inbreeding level is that the equilibrium frequency of recessive detrimental alleles is somewhat lower than expected using avera...
General Dynamic Equivalent Modeling of Microgrid Based on Physical Background
Directory of Open Access Journals (Sweden)
Changchun Cai
2015-11-01
Full Text Available Microgrid is a new power system concept consisting of small-scale distributed energy resources; storage devices and loads. It is necessary to employ a simplified model of microgrid in the simulation of a distribution network integrating large-scale microgrids. Based on the detailed model of the components, an equivalent model of microgrid is proposed in this paper. The equivalent model comprises two parts: namely, equivalent machine component and equivalent static component. Equivalent machine component describes the dynamics of synchronous generator, asynchronous wind turbine and induction motor, equivalent static component describes the dynamics of photovoltaic, storage and static load. The trajectory sensitivities of the equivalent model parameters with respect to the output variables are analyzed. The key parameters that play important roles in the dynamics of the output variables of the equivalent model are identified and included in further parameter estimation. Particle Swarm Optimization (PSO is improved for the parameter estimation of the equivalent model. Simulations are performed in different microgrid operation conditions to evaluate the effectiveness of the equivalent model of microgrid.
Equilibrium Arrival Times to Queues
DEFF Research Database (Denmark)
Breinbjerg, Jesper; Østerdal, Lars Peter
a symmetric (mixed) Nash equilibrium, and show that there is at most one symmetric equilibrium. We provide a numerical method to compute this equilibrium and demonstrate by a numerical example that the social effciency can be lower than the effciency induced by a similar queueing system that serves customers...
Extended Mixed Vector Equilibrium Problems
Directory of Open Access Journals (Sweden)
Mijanur Rahaman
2014-01-01
Full Text Available We study extended mixed vector equilibrium problems, namely, extended weak mixed vector equilibrium problem and extended strong mixed vector equilibrium problem in Hausdorff topological vector spaces. Using generalized KKM-Fan theorem (Ben-El-Mechaiekh et al.; 2005, some existence results for both problems are proved in noncompact domain.
Equivalence principle and gravitational redshift.
Hohensee, Michael A; Chu, Steven; Peters, Achim; Müller, Holger
2011-04-15
We investigate leading order deviations from general relativity that violate the Einstein equivalence principle in the gravitational standard model extension. We show that redshift experiments based on matter waves and clock comparisons are equivalent to one another. Consideration of torsion balance tests, along with matter-wave, microwave, optical, and Mössbauer clock tests, yields comprehensive limits on spin-independent Einstein equivalence principle-violating standard model extension terms at the 10(-6) level.
Testing statistical hypotheses of equivalence
Wellek, Stefan
2010-01-01
Equivalence testing has grown significantly in importance over the last two decades, especially as its relevance to a variety of applications has become understood. Yet published work on the general methodology remains scattered in specialists' journals, and for the most part, it focuses on the relatively narrow topic of bioequivalence assessment.With a far broader perspective, Testing Statistical Hypotheses of Equivalence provides the first comprehensive treatment of statistical equivalence testing. The author addresses a spectrum of specific, two-sided equivalence testing problems, from the
Calculation of individual isotope equilibrium constants for geochemical reactions
Thorstenson, D.C.; Parkhurst, D.L.
2004-01-01
Theory is derived from the work of Urey (Urey H. C. [1947] The thermodynamic properties of isotopic substances. J. Chem. Soc. 562-581) to calculate equilibrium constants commonly used in geochemical equilibrium and reaction-transport models for reactions of individual isotopic species. Urey showed that equilibrium constants of isotope exchange reactions for molecules that contain two or more atoms of the same element in equivalent positions are related to isotope fractionation factors by ?? = (Kex)1/n, where n is the number of atoms exchanged. This relation is extended to include species containing multiple isotopes, for example 13C16O18O and 1H2H18O. The equilibrium constants of the isotope exchange reactions can be expressed as ratios of individual isotope equilibrium constants for geochemical reactions. Knowledge of the equilibrium constant for the dominant isotopic species can then be used to calculate the individual isotope equilibrium constants. Individual isotope equilibrium constants are calculated for the reaction CO2g = CO2aq for all species that can be formed from 12C, 13C, 16O, and 18O; for the reaction between 12C18 O2aq and 1H218Ol; and among the various 1H, 2H, 16O, and 18O species of H2O. This is a subset of a larger number of equilibrium constants calculated elsewhere (Thorstenson D. C. and Parkhurst D. L. [2002] Calculation of individual isotope equilibrium constants for implementation in geochemical models. Water-Resources Investigation Report 02-4172. U.S. Geological Survey). Activity coefficients, activity-concentration conventions for the isotopic variants of H2O in the solvent 1H216Ol, and salt effects on isotope fractionation have been included in the derivations. The effects of nonideality are small because of the chemical similarity of different isotopic species of the same molecule or ion. The temperature dependence of the individual isotope equilibrium constants can be calculated from the temperature dependence of the fractionation
Non-equilibrium thermodynamics
De Groot, Sybren Ruurds
1984-01-01
The study of thermodynamics is especially timely today, as its concepts are being applied to problems in biology, biochemistry, electrochemistry, and engineering. This book treats irreversible processes and phenomena - non-equilibrium thermodynamics.S. R. de Groot and P. Mazur, Professors of Theoretical Physics, present a comprehensive and insightful survey of the foundations of the field, providing the only complete discussion of the fluctuating linear theory of irreversible thermodynamics. The application covers a wide range of topics: the theory of diffusion and heat conduction, fluid dyn
General equilibrium without utility functions
DEFF Research Database (Denmark)
Balasko, Yves; Tvede, Mich
2010-01-01
How far can we go in weakening the assumptions of the general equilibrium model? Existence of equilibrium, structural stability and finiteness of equilibria of regular economies, genericity of regular economies and an index formula for the equilibria of regular economies have been known...... and the diffeomorphism of the equilibrium manifold with a Euclidean space; (2) the diffeomorphism of the set of no-trade equilibria with a Euclidean space; (3) the openness and genericity of the set of regular equilibria as a subset of the equilibrium manifold; (4) for small trade vectors, the uniqueness, regularity...... and stability of equilibrium for two version of tatonnement; (5) the pathconnectedness of the sets of stable equilibria....
Energy Technology Data Exchange (ETDEWEB)
Ortega J, R.; Reyes S, M. A. [Comision Nacional de Seguridad Nuclear y Salvaguardias, Dr. Jose Ma. Barragan 779, Col. Narvarte, 03020 Mexico D. F. (Mexico); Moranchel y R, M., E-mail: rojimenez@cnsns.gob.mx [IPN, Escuela Superior de Fisica y Matematicas, Departamento de Ingenieria Nuclear, Av. Instituto Politecnico Nacional s/n, U. P. Adolfo Lopez Mateos, Edif. 9, Col. San Pedro Zacatenco, 07738 Mexico D. F. (Mexico)
2013-10-15
In Mexico the use of electron accelerators for treating cancerous tumors had grown enormously in the last decade. When the treatments are carried out with X-ray beam energy below 10 MV the design of the shielding of the radioactive facility is determined by analyzing the interaction of X-rays, which have a direct impact and dispersion, with materials of the facility. However, when it makes use of X-ray beam energy equal to or greater than 10 MV the neutrons presence is imminent due to their generation by the interaction of the primary beam X-ray with materials head of the accelerator and of the table of treatment, mainly. In these cases, the design and calculation of shielding considers the generation of high-energy neutrons which contribute the equivalent dose that public and occupationally staff exposed (POE) will receive in the areas surrounding the facility radioactive. However, very few measurements have been performed to determine the actual contribution to the neutron dose equivalent received by POE and public during working hours. This paper presents and estimate of the actual contribution of the neutron dose equivalent received by public and POE facilities in various radioactive medical use, considering many factors. To this end, measurements were made of the equivalent dose by using a neutron monitor in areas surrounding different radioactive installations (of Mexico) which used electron accelerators medical use during treatment with X-ray beam energy equal to or greater than 10 MV. The results are presented after a statistical analysis of a wide range of measures in order to estimate more reliability real contribution of the neutron dose equivalent for POE and the public. (author)
Energy Technology Data Exchange (ETDEWEB)
Gonzalez, Alfonso Mayer; Jimenez, Roberto Ortega; Sanchez, Mario A. Reyes, E-mail: amgesfm@hotmail.com, E-mail: rojimenez@cnsns.gob.mx [Comision Nacional de Seguridad Nuclear y Salvaguardias (CNSNS), Mexico, D.F. (Mexico); Moranchel y Mejia, Mario, E-mail: mmoranchel@ipn.mx [Instituto Politecnico Nacional (ESFM/IPN), Mexico, D.F. (Mexico). Escuela Superior de Fisica y Matematicas. Departamento de lngenieria Nuclear
2013-07-01
In Mexico the use of electron accelerators for treating cancerous tumors had grown enormously in the last decade. When the treatments are carried out with X-ray beam energy below 10 MV the design of the shielding of the radioactive facility is determined by analyzing the interaction of X-rays, which have a direct impact and dispersion, with materials of the facility. However, when it makes use of X-ray beam energy equal to or greater than 10 MV the neutrons presence is imminent due to their generation by the interaction of the primary beam X-ray with materials head of the accelerator and of the table of treatment, mainly. In these cases, the design and calculation of shielding considers the generation of high-energy neutrons which contribute the equivalent dose that public and Occupationally Staff Exposed (POE) will receive in the areas surrounding the facility radioactive. However, very few measurements have been performed to determine the actual contribution to the neutron dose equivalent received by POE and public during working hours. This paper presents an estimate of the actual contribution of the neutron dose equivalent received by public and POE facilities in various radioactive medical use, considering many factors. To this end, measurements were made of the equivalent dose by using a neutron monitor in areas surrounding different radioactive installations (of Mexico) which used electron accelerators medical use during treatment with X-ray beam energy equal to or greater than 10 MV. The results are presented after a statistical analysis of a wide range of measures in order to estimate more reliability real contribution of the neutron dose equivalent for POE and the public. (author)
Emergent constraint on equilibrium climate sensitivity from global temperature variability
Cox, Peter M.; Huntingford, Chris; Williamson, Mark S.
2018-01-01
Equilibrium climate sensitivity (ECS) remains one of the most important unknowns in climate change science. ECS is defined as the global mean warming that would occur if the atmospheric carbon dioxide (CO2) concentration were instantly doubled and the climate were then brought to equilibrium with that new level of CO2. Despite its rather idealized definition, ECS has continuing relevance for international climate change agreements, which are often framed in terms of stabilization of global warming relative to the pre-industrial climate. However, the ‘likely’ range of ECS as stated by the Intergovernmental Panel on Climate Change (IPCC) has remained at 1.5–4.5 degrees Celsius for more than 25 years. The possibility of a value of ECS towards the upper end of this range reduces the feasibility of avoiding 2 degrees Celsius of global warming, as required by the Paris Agreement. Here we present a new emergent constraint on ECS that yields a central estimate of 2.8 degrees Celsius with 66 per cent confidence limits (equivalent to the IPCC ‘likely’ range) of 2.2–3.4 degrees Celsius. Our approach is to focus on the variability of temperature about long-term historical warming, rather than on the warming trend itself. We use an ensemble of climate models to define an emergent relationship between ECS and a theoretically informed metric of global temperature variability. This metric of variability can also be calculated from observational records of global warming, which enables tighter constraints to be placed on ECS, reducing the probability of ECS being less than 1.5 degrees Celsius to less than 3 per cent, and the probability of ECS exceeding 4.5 degrees Celsius to less than 1 per cent.
Maia, Alex S C; Nascimento, Sheila T; Nascimento, Carolina C N; Gebremedhin, Kifle G
2016-05-01
The effects of air temperature and relative humidity on thermal equilibrium of goats in a tropical region was evaluated. Nine non-pregnant Anglo Nubian nanny goats were used in the study. An indirect calorimeter was designed and developed to measure oxygen consumption, carbon dioxide production, methane production and water vapour pressure of the air exhaled from goats. Physiological parameters: rectal temperature, skin temperature, hair-coat temperature, expired air temperature and respiratory rate and volume as well as environmental parameters: air temperature, relative humidity and mean radiant temperature were measured. The results show that respiratory and volume rates and latent heat loss did not change significantly for air temperature between 22 and 26°C. In this temperature range, metabolic heat was lost mainly by convection and long-wave radiation. For temperature greater than 30°C, the goats maintained thermal equilibrium mainly by evaporative heat loss. At the higher air temperature, the respiratory and ventilation rates as well as body temperatures were significantly elevated. It can be concluded that for Anglo Nubian goats, the upper limit of air temperature for comfort is around 26°C when the goats are protected from direct solar radiation. Copyright © 2016 Elsevier Ltd. All rights reserved.
Fitting Proportional Odds Model to Case-Control data with Incorporating Hardy-Weinberg Equilibrium.
Zhang, Wei; Zhang, Zehui; Li, Xinmin; Li, Qizhai
2015-11-26
Genetic association studies have been proved to be an efficient tool to reveal the aetiology of many human complex diseases and traits. When the phenotype is binary, the logistic regression model is commonly employed to evaluate the association strength of the genetic variants predispose to human diseases because the maximum likelihood estimator of the odds ratio based on case-control data is equivalent to that from the same model by taking the data as being arisen prospectively. This equivalence does not hold for the proportional odds model and using it to analyze the case-control data directly often results in a substantial bias. Through putting a parameter of the minor allele frequency in the modified likelihood function under the condition that the Hardy-Weinberg equilibrium law holds within controls, a consistent estimator is obtained. On the basis of it, we construct a score test statistic to test whether the genetic variant is associated with the diseases. Simulation studies show that the proposed estimator has smaller mean squared error than the existing methods when the genetic effect size is away from zero and the proposed test statistic has a good control of type I error rate and is more powerful than the existing procedures. Application to 45 single nucleotide polymorphisms located in the region of TRAF1-C5 genes for the association with four-level anticyclic citrullinated protein antibody from Genetic Analysis Workshop 16 further demonstrates its performance.
Statistical physics ""Beyond equilibrium
Energy Technology Data Exchange (ETDEWEB)
Ecke, Robert E [Los Alamos National Laboratory
2009-01-01
The scientific challenges of the 21st century will increasingly involve competing interactions, geometric frustration, spatial and temporal intrinsic inhomogeneity, nanoscale structures, and interactions spanning many scales. We will focus on a broad class of emerging problems that will require new tools in non-equilibrium statistical physics and that will find application in new material functionality, in predicting complex spatial dynamics, and in understanding novel states of matter. Our work will encompass materials under extreme conditions involving elastic/plastic deformation, competing interactions, intrinsic inhomogeneity, frustration in condensed matter systems, scaling phenomena in disordered materials from glasses to granular matter, quantum chemistry applied to nano-scale materials, soft-matter materials, and spatio-temporal properties of both ordinary and complex fluids.
A confidence-limit-based approach to the assessment of Hardy-Weinberg equilibrium.
Wellek, Stefan; Goddard, Katrina A B; Ziegler, Andreas
2010-04-01
The classical chi(2)-procedure for the assessment of Hardy-Weinberg equilibrium (HWE) is tailored for detecting violations of HWE. However, many applications in genetic epidemiology require approximate compatibility with HWE. In a previous contribution to the field (Wellek, S. (2004). Biometrics, 60, 694-703), the methodology of statistical equivalence testing was exploited for the construction of tests for problems in which the assumption of approximate compatibility of a given genotype distribution with HWE plays the role of the alternative hypothesis one aims to establish. In this article, we propose a procedure serving the same purpose but relying on confidence limits rather than critical bounds of a significance test. Interval estimation relates to essentially the same parametric function that was previously chosen as the target parameter for constructing an exact conditional UMPU test for equivalence with a HWE conforming genotype distribution. This population parameter is shown to have a direct genetic interpretation as a measure of relative excess heterozygosity. Confidence limits are constructed using both asymptotic and exact methods. The new approach is illustrated by reanalyzing genotype distributions obtained from published genetic association studies, and detailed guidance for choosing the equivalence margin is provided. The methods have been implemented in freely available SAS macros.
Wave propagation in equivalent continuums representing truss lattice materials
Energy Technology Data Exchange (ETDEWEB)
Messner, Mark C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Barham, Matthew I. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kumar, Mukul [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Barton, Nathan R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2015-07-29
Stiffness scales linearly with density in stretch-dominated lattice meta-materials offering the possibility of very light yet very stiff structures. Current additive manufacturing techniques can assemble structures consisting of these lattice materials, but the design of such structures will require accurate, efficient simulation techniques. Equivalent continuum models have several advantages over discrete truss models of stretch dominated lattices, including computational efficiency and ease of model construction. However, the development an equivalent model suitable for representing the dynamic response of a periodic truss is complicated by microinertial effects. This paper derives a dynamic equivalent continuum model for periodic truss structures and verifies it against detailed finite element simulations. The model must incorporate microinertial effects to accurately reproduce long-wavelength characteristics of the response such as anisotropic elastic soundspeeds. The formulation presented here also improves upon previous work by preserving equilibrium at truss joints for affine lattice deformation and by improving numerical stability by eliminating vertices in the effective yield surface.
Equilibrium models and variational inequalities
Konnov, Igor
2007-01-01
The concept of equilibrium plays a central role in various applied sciences, such as physics (especially, mechanics), economics, engineering, transportation, sociology, chemistry, biology and other fields. If one can formulate the equilibrium problem in the form of a mathematical model, solutions of the corresponding problem can be used for forecasting the future behavior of very complex systems and, also, for correcting the the current state of the system under control. This book presents a unifying look on different equilibrium concepts in economics, including several models from related sciences.- Presents a unifying look on different equilibrium concepts and also the present state of investigations in this field- Describes static and dynamic input-output models, Walras, Cassel-Wald, spatial price, auction market, oligopolistic equilibrium models, transportation and migration equilibrium models- Covers the basics of theory and solution methods both for the complementarity and variational inequality probl...
On the equilibrium isotopic composition of the thorium–uranium–plutonium fuel cycle
Energy Technology Data Exchange (ETDEWEB)
Marshalkin, V. Ye., E-mail: marshalkin@vniief.ru; Povyshev, V. M. [Russian Federal Nuclear Center—All-Russian Scientific Research Institute of Experimental Physics (Russian Federation)
2016-12-15
The equilibrium isotopic compositions and the times to equilibrium in the process of thorium–uranium–plutonium oxide fuel recycling in VVER-type reactors using heavy water mixed with light water are estimated. It is demonstrated thEhfat such reactors have a capacity to operate with self-reproduction of active isotopes in the equilibrium mode.
Full Static Output Feedback Equivalence
Directory of Open Access Journals (Sweden)
Aristotle G. Yannakoudakis
2013-01-01
Full Text Available We present a constructive solution to the problem of full output feedback equivalence, of linear, minimal, time-invariant systems. The equivalence relation on the set of systems is transformed to another on the set of invertible block Bezout/Hankel matrices using the isotropy subgroups of the full state feedback group and the full output injection group. The transformation achieving equivalence is calculated solving linear systems of equations. We give a polynomial version of the results proving that two systems are full output feedback equivalent, if and only if they have the same family of generalized Bezoutians. We present a new set of output feedback invariant polynomials that generalize the breakaway polynomial of scalar systems.
The paradox of energy equivalence
Isaac, Nick J. B.; Storch, David; Carbone, Chris
2013-01-01
Energy equivalence, the notion that population energy flux is independent of body mass, has become a key concept in ecology. We argue that energy equivalence is not an ecological ‘rule’, as claimed, but a flawed concept beset by circular reasoning. In fact, the independence of mass and energy flux is a null hypothesis. We show that our mechanistic understanding of size–density relationships (SDRs) follows directly from this null model and the assumption that energy limits abundance. Paradoxic...
Underlining some aspects of the equivalence principle
Benedetto, E.; Feoli, A.
2017-09-01
We want to shed light on some discussed aspects of the principle of equivalence. We consider two different phases in the evolution of the principle. We pay attention to the fact that some textbooks do not dwell on the mathematical meaning of ‘locally flat spacetime’, which can confuse students and, occasionally, can also lead to misinterpretations. For example, the non-eliminability of tidal forces, not even locally, may suggest that the equivalence principle is wrong. By contrast, we want to show that this is in perfect agreement with the Einstein geometrical interpretation of spacetime. Finally, in order to check the approximations used in the Gedankenexperiment of an elevator, we estimate explicitly the magnitude of the deflection of light and the effects of tidal forces in a ‘real lift’.
Hsu, Hsiao-Ping; Kremer, Kurt
2017-03-01
We present large-scale molecular dynamics simulations for a coarse-grained model of polymer melts in equilibrium. From detailed Rouse mode analysis we show that the time-dependent relaxation of the autocorrelation function (ACF) of modes p can be well described by the effective stretched exponential function due to the crossover from Rouse to reptation regime. The ACF is independent of chain sizes N for N/p reptation regime. We have also provided evidence that the incoherent dynamic scattering function follows the same crossover scaling behavior of the mean square displacement of monomers at the corresponding characteristic time scales. The decay of the coherent dynamic scattering function is slowed down and a plateau develops as chain sizes increase at the intermediate time and wave length scales. The tube diameter extracted from the coherent dynamic scattering function is equivalent to the previous estimate from the mean square displacement of monomers.
Equilibrium and non-equilibrium effects in nucleus-nucleus collisions
Bravina, L V; Zabrodin, E E; Bass, S A; Belkacem, M; Bleicher, M; Brandstetter, M; Hofmann, M; Soff, S; Spieles, C; Weber, H; Stockerand, H; Greiner, W
1999-01-01
Local thermal and chemical equilibration is studied for central A+A collisions at 10.7-160 AGeV in the ultrarelativistic quantum molecular dynamics model (UrQMD). The UrQMD model exhibits strong deviations from local equilibrium at the high density hadron-string phase formed during the early stage of the collision. Equilibration of the hadron-resonance matter is established in the central cell of volume V=125 fm/sup 3/ at later stages, t>or=10 fm/c, of the resulting quasi-isentropic expansion. The thermodynamical functions in the cell and their time evolution are presented. Deviations of the UrQMD quasi-equilibrium state from the statistical mechanics equilibrium are found. They increase with energy per baryon and lead to a strong enhancement of the pion number density as compared to statistical mechanics estimates at SPS energies. (38 refs).
Directory of Open Access Journals (Sweden)
Geraldo de Albuquerque Maranhão Neto
2008-11-01
Full Text Available O objetivo deste estudo foi realizar a equivalência transcultural de escalas empregadas para a avaliação do nível de atividade física e que são utilizadas como estimativas da aptidão cardiorrespiratória, para posterior utilização em indivíduos idosos. Três escalas foram determinadas após revisão sistemática: Veterans Physical Activity Questionnaire (VSAQ, Rating of Perceived Capacity (RPC e Physical Activity Rating (PA-R. Para a análise da equivalência, utilizou-se o modelo proposto por Herdman et al. Como parte do processo, a confiabilidade teste-reteste foi avaliada em uma amostra composta por 12 idosos com idade de 74,5 ± 3,5 anos, pelo cálculo dos coeficientes de concordância de Lin (CCL e de correlação intraclasse (CCI. Detectou-se uma boa reprodutibilidade das escalas com exceção do RPC. Apesar de a quantidade de indivíduos não permitir conclusões mais aprofundadas, os resultados podem indicar necessidade de mudanças na estrutura de algumas escalas originais. Por fim, acredita-se que os resultados obtidos no presente estudo sugerem a adequação das versões das escalas para a língua portuguesa, havendo, todavia, a necessidade de um estudo de validade de critério das escalas.This study aimed at establishing the cross-cultural equivalence of scales used to evaluate physical activity level and measure cardiorespiratory fitness, for further application in elderly subjects. Three scales were identified after systematic review: Veterans Physical Activity Questionnaire (VSAQ, Rating of Perceived Capacity (RPC, and Physical Activity Rating (PA-R. The model proposed by Herdman et al. was applied to analyze equivalence. Test-retest reliability was calculated in a sample of 12 elderly subjects (74.5 ± 3.5 years using Lin's concordance coefficient and intraclass correlation coefficient. Good reproducibility was detected in all scales except RPC. Due to the small sample size, hardly any conclusions can de drawn, but the
Phillips, Rob
2015-03-01
It has been said that the cell is the test tube of the twenty-first century. If so, the theoretical tools needed to quantitatively and predictively describe what goes on in such test tubes lag sorely behind the stunning experimental advances in biology seen in the decades since the molecular biology revolution began. Perhaps surprisingly, one of the theoretical tools that has been used with great success on problems ranging from how cells communicate with their environment and each other to the nature of the organization of proteins and lipids within the cell membrane is statistical mechanics. A knee-jerk reaction to the use of statistical mechanics in the description of cellular processes is that living organisms are so far from equilibrium that one has no business even thinking about it. But such reactions are probably too hasty given that there are many regimes in which, because of a separation of timescales, for example, such an approach can be a useful first step. In this article, we explore the power of statistical mechanical thinking in the biological setting, with special emphasis on cell signaling and regulation. We show how such models are used to make predictions and describe some recent experiments designed to test them. We also consider the limits of such models based on the relative timescales of the processes of interest.
An equilibrium and kinetic modeling
African Journals Online (AJOL)
SERVER
2007-06-18
Jun 18, 2007 ... The Langmuir and Freundlich adsorption models fitted well with the equilibrium data of the process studied. ... followed the first order rate expression. Key words: Penicillin-G wastewater, Phanerochate chrysosporium, equilibrium, kinetic study. ... Ammonia-nitrogen (mg/l). 300 - 500. Total phosphate (mg/l).
Non-equilibrium phase transitions
Henkel, Malte; Lübeck, Sven
2009-01-01
This book describes two main classes of non-equilibrium phase-transitions: (a) static and dynamics of transitions into an absorbing state, and (b) dynamical scaling in far-from-equilibrium relaxation behaviour and ageing. The first volume begins with an introductory chapter which recalls the main concepts of phase-transitions, set for the convenience of the reader in an equilibrium context. The extension to non-equilibrium systems is made by using directed percolation as the main paradigm of absorbing phase transitions and in view of the richness of the known results an entire chapter is devoted to it, including a discussion of recent experimental results. Scaling theories and a large set of both numerical and analytical methods for the study of non-equilibrium phase transitions are thoroughly discussed. The techniques used for directed percolation are then extended to other universality classes and many important results on model parameters are provided for easy reference.
A Multiperiod Equilibrium Pricing Model
Directory of Open Access Journals (Sweden)
Minsuk Kwak
2014-01-01
Full Text Available We propose an equilibrium pricing model in a dynamic multiperiod stochastic framework with uncertain income. There are one tradable risky asset (stock/commodity, one nontradable underlying (temperature, and also a contingent claim (weather derivative written on the tradable risky asset and the nontradable underlying in the market. The price of the contingent claim is priced in equilibrium by optimal strategies of representative agent and market clearing condition. The risk preferences are of exponential type with a stochastic coefficient of risk aversion. Both subgame perfect strategy and naive strategy are considered and the corresponding equilibrium prices are derived. From the numerical result we examine how the equilibrium prices vary in response to changes in model parameters and highlight the importance of our equilibrium pricing principle.
Equilibrium Bird Species Diversity in Atlantic Islands.
Valente, Luis; Illera, Juan Carlos; Havenstein, Katja; Pallien, Tamara; Etienne, Rampal S; Tiedemann, Ralph
2017-06-05
Half a century ago, MacArthur and Wilson proposed that the number of species on islands tends toward a dynamic equilibrium diversity around which species richness fluctuates [1]. The current prevailing view in island biogeography accepts the fundamentals of MacArthur and Wilson's theory [2] but questions whether their prediction of equilibrium can be fulfilled over evolutionary timescales, given the unpredictable and ever-changing nature of island geological and biotic features [3-7]. Here we conduct a complete molecular phylogenetic survey of the terrestrial bird species from four oceanic archipelagos that make up the diverse Macaronesian bioregion-the Azores, the Canary Islands, Cape Verde, and Madeira [8, 9]. We estimate the times at which birds colonized and speciated in the four archipelagos, including many previously unsampled endemic and non-endemic taxa and their closest continental relatives. We develop and fit a new multi-archipelago dynamic stochastic model to these data, explicitly incorporating information from 91 taxa, both extant and extinct. Remarkably, we find that all four archipelagos have independently achieved and maintained a dynamic equilibrium over millions of years. Biogeographical rates are homogeneous across archipelagos, except for the Canary Islands, which exhibit higher speciation and colonization. Our finding that the avian communities of the four Macaronesian archipelagos display an equilibrium diversity pattern indicates that a diversity plateau may be rapidly achieved on islands where rates of in situ radiation are low and extinction is high. This study reveals that equilibrium processes may be more prevalent than recently proposed, supporting MacArthur and Wilson's 50-year-old theory. Copyright © 2017 Elsevier Ltd. All rights reserved.
Quantum non-equilibrium and relaxation to equilibrium for a class of de Broglie-Bohm-type theories
Energy Technology Data Exchange (ETDEWEB)
Colin, Samuel [Centre for Quantum Dynamics, Griffith University, Brisbane, QLD 4111 (Australia); Struyve, Ward [Institute of Theoretical Physics, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium)], E-mail: s.colin@griffith.edu.au, E-mail: Ward.Struyve@fys.kuleuven.be
2010-04-15
The de Broglie-Bohm theory is about non-relativistic point-particles that move deterministically along trajectories. The theory reproduces the predictions of standard quantum theory, given that the distribution of particles over an ensemble of systems, all described by the same wavefunction {psi}, equals the quantum equilibrium distribution |{psi}|{sup 2}. Numerical simulations done by Valentini and Westman (2005 Proc. R. Soc. A 461 253) have illustrated that non-equilibrium particle distributions may relax to quantum equilibrium after some time. Here we consider non-equilibrium distributions and their relaxation properties for a particular class of trajectory theories (first studied in detail by Deotto and Ghirardi (1998 Found. Phys. 28 1)) that are empirically equivalent to the de Broglie-Bohm theory in quantum equilibrium. In the examples we studied of such theories, we found a speed-up of the relaxation, compared to the ordinary de Broglie-Bohm theory. Hence non-equilibrium predictions that depend strongly on relaxation properties, such as those studied recently by Valentini, may vary across different trajectory theories. As such, these theories might be experimentally distinguishable.
Nash equilibrium and multi criterion aerodynamic optimization
Tang, Zhili; Zhang, Lianhe
2016-06-01
Game theory and its particular Nash Equilibrium (NE) are gaining importance in solving Multi Criterion Optimization (MCO) in engineering problems over the past decade. The solution of a MCO problem can be viewed as a NE under the concept of competitive games. This paper surveyed/proposed four efficient algorithms for calculating a NE of a MCO problem. Existence and equivalence of the solution are analyzed and proved in the paper based on fixed point theorem. Specific virtual symmetric Nash game is also presented to set up an optimization strategy for single objective optimization problems. Two numerical examples are presented to verify proposed algorithms. One is mathematical functions' optimization to illustrate detailed numerical procedures of algorithms, the other is aerodynamic drag reduction of civil transport wing fuselage configuration by using virtual game. The successful application validates efficiency of algorithms in solving complex aerodynamic optimization problem.
Calculation of individual isotope equilibrium constants for implementation in geochemical models
Thorstenson, Donald C.; Parkhurst, David L.
2002-01-01
Theory is derived from the work of Urey to calculate equilibrium constants commonly used in geochemical equilibrium and reaction-transport models for reactions of individual isotopic species. Urey showed that equilibrium constants of isotope exchange reactions for molecules that contain two or more atoms of the same element in equivalent positions are related to isotope fractionation factors by , where is n the number of atoms exchanged. This relation is extended to include species containing multiple isotopes, for example and , and to include the effects of nonideality. The equilibrium constants of the isotope exchange reactions provide a basis for calculating the individual isotope equilibrium constants for the geochemical modeling reactions. The temperature dependence of the individual isotope equilibrium constants can be calculated from the temperature dependence of the fractionation factors. Equilibrium constants are calculated for all species that can be formed from and selected species containing , in the molecules and the ion pairs with where the subscripts g, aq, l, and s refer to gas, aqueous, liquid, and solid, respectively. These equilibrium constants are used in the geochemical model PHREEQC to produce an equilibrium and reaction-transport model that includes these isotopic species. Methods are presented for calculation of the individual isotope equilibrium constants for the asymmetric bicarbonate ion. An example calculates the equilibrium of multiple isotopes among multiple species and phases.
Matching of equivalent field regions
DEFF Research Database (Denmark)
Appel-Hansen, Jørgen; Rengarajan, S.B.
2005-01-01
screen, having the same homogeneous medium on both sides and an impressed current on one aide, an alternative procedure is relevant. We make use of the fact that in the aperture the tangential component of the magnetic field due to the induced currents in the screen is zero. The use of such a procedure......In aperture problems, integral equations for equivalent currents are often found by enforcing matching of equivalent fields. The enforcement is made in the aperture surface region adjoining the two volumes on each side of the aperture. In the case of an aperture in a planar perfectly conducting...... shows that equivalent currents can be found by a consideration of only one of the two volumes into which the aperture plane divides the space. Furthermore, from a consideration of an automatic matching at the aperture, additional information about tangential as well as normal field components...
Equivalent linearization of nonlinear forces
Meng, Guang; Xue, Zhongqing
1987-07-01
A method used for equivalent linearization of the two orthogonal squeeze-film forces is extended here to the general case of n degrees of freedom and n components of nonlinear forces, and the expressions for equivalent linear coefficients are derived. Nonlinear forces can be linearized by the methods of Fourier expansion, active and reactive powers, or mean-square error. The n components of nonlinear forces can all be expressed formally as the sum of an average force, a linear spring force, and a linear damping force. This paper also gives a flow chart for calculating the steady-state responses of a nonlinear system with many degrees of freedom, using the method of equivalent linearization. The resulting saving in computation time is demonstrated by a numerical example of a flexible rotor-bearing system with a noncentralized squeeze-film damper.
Dynamical Detailed Balance and Local Kms Condition for Non-Equilibrium States
Accardi, Luigi; Imafuku, Kentaro
The principle of detailed balance is at the basis of equilibrium physics and is equivalent to the Kubo-Martin-Schwinger (KMS) condition (under quite general assumptions). In the present paper we prove that a large class of non-equilibrium quantum systems satisfies a dynamical generalization of the detailed balance condition (dynamical detailed balance) expressing the fact that all the micro-currents, associated to the Bohr frequencies are constant. The usual (equilibrium) detailed balance condition is characterized by the property that this constant is identically zero. From this we deduce a simple and experimentally measurable relation expressing the microcurrent associated to a transition between two levels ɛm→ɛn as a linear combination of the occupation probabilities of the two levels, with coefficients given by the generalized susceptivities (transport coefficients). We then give a second characterization of the dynamical detailed balance condition using a master equation rather than the microcurrents. Finally we show that these two conditions are equivalent to a "local" generalization of the usual KMS condition. Summing up: rather than postulating some ansatz on the basis of phenomenological models or of numerical simulations, we deduce, directly in the quantum domain and from fundamental principles, some natural and simple non equilibrium generalizations of the three main characterizations of equilibrium states. Then we prove that these three, apparently very far, conditions are equivalent. These facts support our convinction that these three equivalent conditions capture a universal aspect of non equilibrium phenomena.
Applicability constraints of the equivalence theorem
Energy Technology Data Exchange (ETDEWEB)
Dobado, A.; Pelaez, J.R. [Departamento de Fisica Teorica, Universidad Complutense, 28040 Madrid (Spain); Urdiales, M.T. [Departamento de Fisica Teorica, Universidad Autonoma, 28049 Madrid (Spain)
1997-12-01
In this work we study the applicability of the equivalence theorem, either for unitary models or within an effective Lagrangian approach. There are two types of limitations: the existence of a validity energy window and the use of the lowest order in the electroweak constants. For the first kind, we consider some methods, based on dispersion theory or the large N limit, that allow us to extend the applicability. For the second, we obtain numerical estimates of the effect of neglecting higher orders in the perturbative expansion. {copyright} {ital 1997} {ital The American Physical Society}
Golden, R; Valentini, M
2014-07-01
Due largely to the controversy concerning the potential human health effects from exposure to formaldehyde gas in conjunction with the misunderstanding of the well-established equilibrium relationship with its hydrated reaction product, methylene glycol, the concept of chemical equivalence between these two distinctly different chemicals has been adopted by regulatory authorities. Chemical equivalence implies not only that any concentration of methylene glycol under some condition of use would be nearly or completely converted into formaldehyde gas, but also that these two substances would be toxicologically equivalent as well. A relatively simple worst case experiment using 37% formalin (i.e., concentrated methylene glycol) dispels the concept of chemical equivalence and a review of relevant literature demonstrates that methylene glycol has no inherent toxicity apart from whatever concentration of formaldehyde that might be present in equilibrium with such solutions. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.
Slope stability analysis using limit equilibrium method in nonlinear criterion.
Lin, Hang; Zhong, Wenwen; Xiong, Wei; Tang, Wenyu
2014-01-01
In slope stability analysis, the limit equilibrium method is usually used to calculate the safety factor of slope based on Mohr-Coulomb criterion. However, Mohr-Coulomb criterion is restricted to the description of rock mass. To overcome its shortcomings, this paper combined Hoek-Brown criterion and limit equilibrium method and proposed an equation for calculating the safety factor of slope with limit equilibrium method in Hoek-Brown criterion through equivalent cohesive strength and the friction angle. Moreover, this paper investigates the impact of Hoek-Brown parameters on the safety factor of slope, which reveals that there is linear relation between equivalent cohesive strength and weakening factor D. However, there are nonlinear relations between equivalent cohesive strength and Geological Strength Index (GSI), the uniaxial compressive strength of intact rock σ ci , and the parameter of intact rock m i . There is nonlinear relation between the friction angle and all Hoek-Brown parameters. With the increase of D, the safety factor of slope F decreases linearly; with the increase of GSI, F increases nonlinearly; when σ ci is relatively small, the relation between F and σ ci is nonlinear, but when σ ci is relatively large, the relation is linear; with the increase of m i , F decreases first and then increases.
Determining sample size when assessing mean equivalence.
Asberg, Arne; Solem, Kristine B; Mikkelsen, Gustav
2014-11-01
When we want to assess whether two analytical methods are equivalent, we could test if the difference between the mean results is within the specification limits of 0 ± an acceptance criterion. Testing the null hypothesis of zero difference is less interesting, and so is the sample size estimation based on testing that hypothesis. Power function curves for equivalence testing experiments are not widely available. In this paper we present power function curves to help decide on the number of measurements when testing equivalence between the means of two analytical methods. Computer simulation was used to calculate the probability that the 90% confidence interval for the difference between the means of two analytical methods would exceed the specification limits of 0 ± 1, 0 ± 2 or 0 ± 3 analytical standard deviations (SDa), respectively. The probability of getting a nonequivalence alarm increases with increasing difference between the means when the difference is well within the specification limits. The probability increases with decreasing sample size and with smaller acceptance criteria. We may need at least 40-50 measurements with each analytical method when the specification limits are 0 ± 1 SDa, and 10-15 and 5-10 when the specification limits are 0 ± 2 and 0 ± 3 SDa, respectively. The power function curves provide information of the probability of false alarm, so that we can decide on the sample size under less uncertainty.
Non-equilibrium supramolecular polymerization.
Sorrenti, Alessandro; Leira-Iglesias, Jorge; Markvoort, Albert J; de Greef, Tom F A; Hermans, Thomas M
2017-09-18
Supramolecular polymerization has been traditionally focused on the thermodynamic equilibrium state, where one-dimensional assemblies reside at the global minimum of the Gibbs free energy. The pathway and rate to reach the equilibrium state are irrelevant, and the resulting assemblies remain unchanged over time. In the past decade, the focus has shifted to kinetically trapped (non-dissipative non-equilibrium) structures that heavily depend on the method of preparation (i.e., pathway complexity), and where the assembly rates are of key importance. Kinetic models have greatly improved our understanding of competing pathways, and shown how to steer supramolecular polymerization in the desired direction (i.e., pathway selection). The most recent innovation in the field relies on energy or mass input that is dissipated to keep the system away from the thermodynamic equilibrium (or from other non-dissipative states). This tutorial review aims to provide the reader with a set of tools to identify different types of self-assembled states that have been explored so far. In particular, we aim to clarify the often unclear use of the term "non-equilibrium self-assembly" by subdividing systems into dissipative, and non-dissipative non-equilibrium states. Examples are given for each of the states, with a focus on non-dissipative non-equilibrium states found in one-dimensional supramolecular polymerization.
Spontaneity and Equilibrium: Why "?G Equilibrium" Are Incorrect
Raff, Lionel M.
2014-01-01
The fundamental criteria for chemical reactions to be spontaneous in a given direction are generally incorrectly stated as ?G equilibrium are also misstated as being ?G = 0 or ?A = 0. Following a brief review of the…
Equilibrium with arbitrary market structure
DEFF Research Database (Denmark)
Grodal, Birgit; Vind, Karl
2005-01-01
Fifty years ago Arrow [1] introduced contingent commodities and Debreu [4] observed that this reinterpretation of a commodity was enough to apply the existing general equilibrium theory to uncertainty and time. This interpretation of general equilibrium theory is the Arrow-Debreu model....... The complete market predicted by this theory is clearly unrealistic, and Radner [10] formulated and proved existence of equilibrium in a multiperiod model with incomplete markets. In this paper the Radner result is extended. Radner assumed a specific structure of markets, independence of preferences...
Steganographic Capacity of Images, based on Image Equivalence Classes
DEFF Research Database (Denmark)
Hansen, Klaus; Hammer, Christian; Andersen, Jens Damgaard
2001-01-01
The problem of hiding information imperceptibly can be formulated as the problem of determining if a given image is a member of a sufficiently large equivalence class of images which to the Human Visual System appears to be the same image. This makes it possible to replace the given image...... with a modified image similar in appearance but carrying imperceptibly coded information. This paper presents a framework and an experimental algorithm to estimate upper bounds for the size of an equivalence class....
Theory of Covariance Equivalent ARMAV Models of Civil Engineering Structures
DEFF Research Database (Denmark)
Andersen, P.; Brincker, Rune; Kirkegaard, Poul Henning
1996-01-01
In this paper the theoretical background for using covariance equivalent ARMAV models in modal analysis is discussed. It is shown how to obtain a covariance equivalent ARMA model for a univariate linear second order continous-time system excited by Gaussian white noise. This result is generalized...... for multi-variate systems to an ARMAV model. The covariance equivalent model structure is also considered when the number of channels are different from the number of degrees offreedom to be modelled. Finally, it is reviewed how to estimate an ARMAV model from sampled data....
Theory of Covariance Equivalent ARMAV Models of Civil Engineering Structures
DEFF Research Database (Denmark)
Andersen, P.; Brincker, Rune; Kirkegaard, Poul Henning
In this paper the theoretical background for using covariance equivalent ARMAV models in modal analysis is discussed. It is shown how to obtain a covariance equivalent ARMA model for a univariate linear second order continuous-time system excited by Gaussian white noise. This result is generalized...... for multivariate systems to an ARMAV model. The covariance equivalent model structure is also considered when the number of channels are different from the number of degrees of freedom to be modelled. Finally, it is reviewed how to estimate an ARMAV model from sampled data....
TNT Equivalency of Bulk Nitrocellulose
1981-03-01
Whien Dato Enlotod) &,1W SUMMARY Nitrocellulose, 13.157 nitrogen MIL-N-244A Grade C (Lot number RAD78F0015027) was detonated in configurations...weight factored out, the calculated TNT equivalencies were tabularized and plotted as functions of sample scaled distance. TEST RESULTS Data sheets for
Comments on field equivalence principles
DEFF Research Database (Denmark)
Appel-Hansen, Jørgen
1987-01-01
It is pointed Out that often-used arguments based on a short-circuit concept in presentations of field equivalence principles are not correct. An alternative presentation based on the uniqueness theorem is given. It does not contradict the results obtained by using the short-circuit concept...
Equilibrium and Orientation in Cephalopods.
Budelmann, Bernd-Ulrich
1980-01-01
Describes the structure of the equilibrium receptor system in cephalopods, comparing it to the vertebrate counterpart--the vestibular system. Relates the evolution of this complex system to the competition of cephalopods with fishes. (CS)
EQUIVALENCE VERSUS NON-EQUIVALENCE IN ECONOMIC TRANSLATION
Directory of Open Access Journals (Sweden)
Cristina, Chifane
2012-01-01
Full Text Available This paper aims at highlighting the fact that “equivalence” represents a concept worth revisiting and detailing upon when tackling the translation process of economic texts both from English into Romanian and from Romanian into English. Far from being exhaustive, our analysis will focus upon the problems arising from the lack of equivalence at the word level. Consequently, relevant examples from the economic field will be provided to account for the following types of non-equivalence at word level: culturespecific concepts; the source language concept is not lexicalised in the target language; the source language word is semantically complex; differences in physical and interpersonal perspective; differences in expressive meaning; differences in form; differences in frequency and purpose of using specific forms and the use of loan words in the source text. Likewise, we shall illustrate a number of translation strategies necessary to deal with the afore-mentioned cases of non-equivalence: translation by a more general word (superordinate; translation by a more neutral/less expressive word; translation by cultural substitution; translation using a loan word or loan word plus explanation; translation by paraphrase using a related word; translation by paraphrase using unrelated words; translation by omission and translation by illustration.
Non-Equilibrium Quantum Dissipation
Segal, Dvira; Reichman, David R.; Millis, Andrew J.
2007-01-01
Dissipative processes in non-equilibrium many-body systems are fundamentally different than their equilibrium counterparts. Such processes are of great importance for the understanding of relaxation in single molecule devices. As a detailed case study, we investigate here a generic spin-fermion model, where a two-level system couples to two metallic leads with different chemical potentials. We present results for the spin relaxation rate in the nonadiabatic limit for an arbitrary coupling to ...
Stochastic User Equilibrium Assignment in Schedule-Based Transit Networks with Capacity Constraints
Directory of Open Access Journals (Sweden)
Wangtu Xu
2012-01-01
Full Text Available This paper proposes a stochastic user equilibrium (SUE assignment model for a schedule-based transit network with capacity constraint. We consider a situation in which passengers do not have the full knowledge about the condition of the network and select paths that minimize a generalized cost function encompassing five components: (1 ride time, which is composed of in-vehicle and waiting times, (2 overload delay, (3 fare, (4 transfer constraints, and (5 departure time difference. We split passenger demands among connections which are the space-time paths between OD pairs of the network. All transit vehicles have a fixed capacity and operate according to some preset timetables. When the capacity constraint of the transit line segment is reached, we show that the Lagrange multipliers of the mathematical programming problem are equivalent to the equilibrium passenger overload delay in the congested transit network. The proposed model can simultaneously predict how passengers choose their transit vehicles to minimize their travel costs and estimate the associated costs in a schedule-based congested transit network. A numerical example is used to illustrate the performance of the proposed model.
Shape characteristics of equilibrium and non-equilibrium fractal clusters.
Mansfield, Marc L; Douglas, Jack F
2013-07-28
It is often difficult in practice to discriminate between equilibrium and non-equilibrium nanoparticle or colloidal-particle clusters that form through aggregation in gas or solution phases. Scattering studies often permit the determination of an apparent fractal dimension, but both equilibrium and non-equilibrium clusters in three dimensions frequently have fractal dimensions near 2, so that it is often not possible to discriminate on the basis of this geometrical property. A survey of the anisotropy of a wide variety of polymeric structures (linear and ring random and self-avoiding random walks, percolation clusters, lattice animals, diffusion-limited aggregates, and Eden clusters) based on the principal components of both the radius of gyration and electric polarizability tensor indicates, perhaps counter-intuitively, that self-similar equilibrium clusters tend to be intrinsically anisotropic at all sizes, while non-equilibrium processes such as diffusion-limited aggregation or Eden growth tend to be isotropic in the large-mass limit, providing a potential means of discriminating these clusters experimentally if anisotropy could be determined along with the fractal dimension. Equilibrium polymer structures, such as flexible polymer chains, are normally self-similar due to the existence of only a single relevant length scale, and are thus anisotropic at all length scales, while non-equilibrium polymer structures that grow irreversibly in time eventually become isotropic if there is no difference in the average growth rates in different directions. There is apparently no proof of these general trends and little theoretical insight into what controls the universal anisotropy in equilibrium polymer structures of various kinds. This is an obvious topic of theoretical investigation, as well as a matter of practical interest. To address this general problem, we consider two experimentally accessible ratios, one between the hydrodynamic and gyration radii, the other
Manjunath, S V; Kumar, S Mathava; Ngo, Huu Hao; Guo, Wenshan
2017-12-06
Metronidazole (MNZ) removal by two adsorbents, i.e., concrete-containing graphene (CG) and powder-activated carbon (PAC), was investigated via batch-mode experiments and the outcomes were used to analyze the kinetics, equilibrium and thermodynamics of MNZ adsorption. MNZ sorption on CG and PAC has followed the pseudo-second-order kinetic model, and the thermodynamic parameters revealed that MNZ adsorption was spontaneous on PAC and non-spontaneous on CG. Subsequently, two-parameter isotherm models, i.e., Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Elovich models, were applied to evaluate the MNZ adsorption capacity. The maximum MNZ adsorption capacities ([Formula: see text]) of PAC and CG were found to be between 25.5-32.8 mg/g and 0.41-0.002 mg/g, respectively. Subsequently, the effects of pH, temperature and adsorbent dosage on MNZ adsorption were evaluated by a central composite design (CCD) approach. The CCD experiments have pointed out the complete removal of MNZ at a much lower PAC dosage by increasing the system temperature (i.e., from 20°C to 40°C). On the other hand, a desorption experiment has shown 3.5% and 1.7% MNZ removal from the surface of PAC and CG, respectively, which was insignificant compared to the sorbed MNZ on the surface by adsorption. The overall findings indicate that PAC and CG with higher graphene content could be useful in MNZ removal from aqueous systems.
Directory of Open Access Journals (Sweden)
Klára Plecitá
2012-01-01
Full Text Available This paper focuses on the intra-euro-area imbalances. Therefore the first aim of this paper is to identify euro-area countries exhibiting macroeconomic imbalances. The subsequent aim is to estimate equilibrium real exchange rates for these countries and to compute their degrees of real exchange rate misalignment. The intra-area balance is assessed using the Cluster Analysis and the Principle Component Analysis; on this basis Greece and Ireland are selected as the two euro-area countries with largest imbalances in 2010. Further the medium-run equilibrium exchange rates for Greece and Ireland are estimated applying the Behavioral Equilibrium Exchange Rate (BEER approach popularised by Clark and MacDonald (1998. In addition, the long-run equilibrium exchange rates are estimated using the Permanent Equilibrium Exchange Rate (PEER model. Employing the BEER and PEER approaches on quarterly time series of real effective exchange rates (REER from 1997: Q1 to 2010: Q4 we identify an undervaluation of the Greek and Irish REER around their entrance to the euro area. For the rest of the period analysed their REER is broadly in line with estimated BEER and PEER levels.
Equilibrium and non-equilibrium dynamics simultaneously operate in the Galápagos islands.
Valente, Luis M; Phillimore, Albert B; Etienne, Rampal S
2015-08-01
Island biotas emerge from the interplay between colonisation, speciation and extinction and are often the scene of spectacular adaptive radiations. A common assumption is that insular diversity is at a dynamic equilibrium, but for remote islands, such as Hawaii or Galápagos, this idea remains untested. Here, we reconstruct the temporal accumulation of terrestrial bird species of the Galápagos using a novel phylogenetic method that estimates rates of biota assembly for an entire community. We show that species richness on the archipelago is in an ascending phase and does not tend towards equilibrium. The majority of the avifauna diversifies at a slow rate, without detectable ecological limits. However, Darwin's finches form an exception: they rapidly reach a carrying capacity and subsequently follow a coalescent-like diversification process. Together, these results suggest that avian diversity of remote islands is rising, and challenge the mutual exclusivity of the non-equilibrium and equilibrium ecological paradigms. © 2015 The Authors Ecology Letters published by John Wiley & Sons Ltd and CNRS.
Equivalent statistics and data interpretation.
Francis, Gregory
2017-08-01
Recent reform efforts in psychological science have led to a plethora of choices for scientists to analyze their data. A scientist making an inference about their data must now decide whether to report a p value, summarize the data with a standardized effect size and its confidence interval, report a Bayes Factor, or use other model comparison methods. To make good choices among these options, it is necessary for researchers to understand the characteristics of the various statistics used by the different analysis frameworks. Toward that end, this paper makes two contributions. First, it shows that for the case of a two-sample t test with known sample sizes, many different summary statistics are mathematically equivalent in the sense that they are based on the very same information in the data set. When the sample sizes are known, the p value provides as much information about a data set as the confidence interval of Cohen's d or a JZS Bayes factor. Second, this equivalence means that different analysis methods differ only in their interpretation of the empirical data. At first glance, it might seem that mathematical equivalence of the statistics suggests that it does not matter much which statistic is reported, but the opposite is true because the appropriateness of a reported statistic is relative to the inference it promotes. Accordingly, scientists should choose an analysis method appropriate for their scientific investigation. A direct comparison of the different inferential frameworks provides some guidance for scientists to make good choices and improve scientific practice.
Calculation Method for Equilibrium Points in Dynamical Systems Based on Adaptive Sinchronization
Directory of Open Access Journals (Sweden)
Manuel Prian Rodríguez
2017-12-01
Full Text Available In this work, a control system is proposed as an equivalent numerical procedure whose aim is to obtain the natural equilibrium points of a dynamical system. These equilibrium points may be employed later as setpoint signal for different control techniques. The proposed procedure is based on the adaptive synchronization between an oscillator and a reference model driven by the oscillator state variables. A stability analysis is carried out and a simplified algorithm is proposed. Finally, satisfactory simulation results are shown.
Exploring the Gap between Perfect Bayesian Equilibrium and Sequential Equilibrium
Directory of Open Access Journals (Sweden)
Giacomo Bonanno
2016-11-01
Full Text Available In (Bonanno, 2013, a solution concept for extensive-form games, called perfect Bayesian equilibrium (PBE, was introduced and shown to be a strict refinement of subgame-perfect equilibrium; it was also shown that, in turn, sequential equilibrium (SE is a strict refinement of PBE. In (Bonanno, 2016, the notion of PBE was used to provide a characterization of SE in terms of a strengthening of the two defining components of PBE (besides sequential rationality, namely AGM consistency and Bayes consistency. In this paper we explore the gap between PBE and SE by identifying solution concepts that lie strictly between PBE and SE; these solution concepts embody a notion of “conservative” belief revision. Furthermore, we provide a method for determining if a plausibility order on the set of histories is choice measurable, which is a necessary condition for a PBE to be a SE.
Equivalence relations of AF-algebra extensions
Indian Academy of Sciences (India)
In this paper, we consider equivalence relations of *-algebra extensions and describe the relationship between the isomorphism equivalence and the unitary equivalence. We also show that a certain group homomorphism is the obstruction for these equivalence relations to be the same.
Local Equilibrium and Retardation Revisited.
Hansen, Scott K; Vesselinov, Velimir V
2018-01-01
In modeling solute transport with mobile-immobile mass transfer (MIMT), it is common to use an advection-dispersion equation (ADE) with a retardation factor, or retarded ADE. This is commonly referred to as making the local equilibrium assumption (LEA). Assuming local equilibrium, Eulerian textbook treatments derive the retarded ADE, ostensibly exactly. However, other authors have presented rigorous mathematical derivations of the dispersive effect of MIMT, applicable even in the case of arbitrarily fast mass transfer. We resolve the apparent contradiction between these seemingly exact derivations by adopting a Lagrangian point of view. We show that local equilibrium constrains the expected time immobile, whereas the retarded ADE actually embeds a stronger, nonphysical, constraint: that all particles spend the same amount of every time increment immobile. Eulerian derivations of the retarded ADE thus silently commit the gambler's fallacy, leading them to ignore dispersion due to mass transfer that is correctly modeled by other approaches. We then present a particle tracking simulation illustrating how poor an approximation the retarded ADE may be, even when mobile and immobile plumes are continually near local equilibrium. We note that classic "LEA" (actually, retarded ADE validity) criteria test for insignificance of MIMT-driven dispersion relative to hydrodynamic dispersion, rather than for local equilibrium. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.
A Quasi-Variational Approach for the Dynamic Oligopolistic Market Equilibrium Problem
Directory of Open Access Journals (Sweden)
Annamaria Barbagallo
2013-01-01
Full Text Available The paper is concerned with the dynamic oligopolistic market equilibrium problem in the realistic case in which we allow the presence of capacity constraints and production excesses and, moreover, we assume that the production function depends not only on the time but also on the equilibrium distribution. As a consequence, we introduce the generalized dynamic Cournot-Nash principle in the elastic case and prove the equivalence between this equilibrium definition and a suitable evolutionary quasi-variational inequality. For completeness we make the analysis of existence, regularity, and sensitivity of the solution. In the end, a numerical example is provided.
Gaffney, Terence
2000-05-01
We use the theory of the integral closure of an ideal to study the equivalence of map-germs under C0 coordinate changes in the target. We also derive a formula for the number of double points of a map germ from Cn [rightward arrow] C2n in terms of the Segre number of dimension 0 of an ideal associated to the double point locus of f, and the number of Whitney umbrellas of the composition of f with a generic projection to C2n[minus sign]1.
Chemical Principles Revisited: Using the Equilibrium Concept.
Mickey, Charles D., Ed.
1981-01-01
Discusses the concept of equilibrium in chemical systems, particularly in relation to predicting the position of equilibrium, predicting spontaneity of a reaction, quantitative applications of the equilibrium constant, heterogeneous equilibrium, determination of the solubility product constant, common-ion effect, and dissolution of precipitates.…
The Equilibrium Rule--A Personal Discovery
Hewitt, Paul G.
2016-01-01
Examples of equilibrium are evident everywhere and the equilibrium rule provides a reasoned way to view all things, whether in static (balancing rocks, steel beams in building construction) or dynamic (airplanes, bowling balls) equilibrium. Interestingly, the equilibrium rule applies not just to objects at rest but whenever any object or system of…
Free fall and the equivalence principle revisited
Pendrill, Ann-Marie
2017-11-01
Free fall is commonly discussed as an example of the equivalence principle, in the context of a homogeneous gravitational field, which is a reasonable approximation for small test masses falling moderate distances. Newton’s law of gravity provides a generalisation to larger distances, and also brings in an inhomogeneity in the gravitational field. In addition, Newton’s third law of action and reaction causes the Earth to accelerate towards the falling object, bringing in a mass dependence in the time required for an object to reach ground—in spite of the equivalence between inertial and gravitational mass. These aspects are rarely discussed in textbooks when the motion of everyday objects are discussed. Although these effects are extremely small, it may still be important for teachers to make assumptions and approximations explicit, to be aware of small corrections, and also to be prepared to estimate their size. Even if the corrections are not part of regular teaching, some students may reflect on them, and their questions deserve to be taken seriously.
Nash equilibrium with lower probabilities
DEFF Research Database (Denmark)
Groes, Ebbe; Jacobsen, Hans Jørgen; Sloth, Birgitte
1998-01-01
We generalize the concept of Nash equilibrium in mixed strategies for strategic form games to allow for ambiguity in the players' expectations. In contrast to other contributions, we model ambiguity by means of so-called lower probability measures or belief functions, which makes it possible...... to distinguish between a player's assessment of ambiguity and his attitude towards ambiguity. We also generalize the concept of trembling hand perfect equilibrium. Finally, we demonstrate that for certain attitudes towards ambiguity it is possible to explain cooperation in the one-shot Prisoner's Dilemma...
Delegation Principle for Multi-agency Games under Ex Post Equilibrium
Yu Chen; Zhenhua Wu
2012-01-01
We explore the strategic equivalence of the delegated menu contracting procedure in pure-strategy multi-agency games under ex post equilibrium. Our model setup permits "full-blown interdependence," including information externality, contract externality, correlated types, and primitive constraints across the contracts for different agents. Our delegation principle identifies that (optimal) ex post menu design is strategically equivalent to (optimal) bilateral ex post mechanism design, which s...
Chiang, Y; Kresge, A J; Zhu, Y
2002-06-05
Flash photolysis of p-hydroxybenzyl acetate in aqueous perchloric acid solution and formic acid, acetic acid, biphosphate ion, and tris(hydroxymethyl)methylammonium ion buffers produced p-quinone methide as a short-lived species that underwent hydration to p-hydroxybenzyl alcohol in hydronium ion catalyzed (k(H(+)) = 5.28 x 10(4) M(-1) s(-1)) and uncatalyzed (k(uc) = 3.33 s(-1)) processes. The inverse nature of the solvent isotope effect on the hydronium ion-catalyzed reaction, k(H(+))/k(D(+)) = 0.41, indicates that this process occurs by rapid and reversible protonation of the quinone methide on its carbonyl carbon atom, followed by rate-determining capture of the p-hydroxybenzyl carbocation so produced by water, while the magnitude of the rate constant on the uncatalyzed process indicates that this reaction occurs by simple nucleophilic addition of water to the methylene group of the quinone methide. p-Quinone methide also underwent hydronium ion-catalyzed and uncatalyzed nucleophilic addition reactions with chloride ion, bromide ion, thiocyanate ion, and thiourea. The solvent isotope effects on the hydronium ion-catalyzed processes again indicate that these reactions occurred by preequilibrium mechanisms involving a p-hydroxybenzyl carbocation intermediate, and assignment of a diffusion-controlled value to the rate constant for reaction of this cation with thiocyanate ion led to K(SH) = 110 M as the acidity constant of oxygen-protonated p-quinone methide. In a certain perchloric acid concentration range, the bromide ion reaction became biphasic, and least-squares analysis of the kinetic data using a double-exponential function provided k(Br(-)) = 3.8 x 10(8) M(-1) s(-1) as the rate constant for nucleophilic capture of the p-hydroxybenzyl carbocation by bromide ion, k(ionz) = 8.5 x 10(2) s(-1) for ionization of the carbon-bromine bond of p-hydroxybenzyl bromide, and K = 4.5 x 10(5) M(-1) as the equilibrium constant for the carbocation-bromide ion combination
Influence of temperature fluctuations on equilibrium ice sheet volume
Directory of Open Access Journals (Sweden)
T. B. Mikkelsen
2018-01-01
Full Text Available Forecasting the future sea level relies on accurate modeling of the response of the Greenland and Antarctic ice sheets to changing temperatures. The surface mass balance (SMB of the Greenland Ice Sheet (GrIS has a nonlinear response to warming. Cold and warm anomalies of equal size do not cancel out and it is therefore important to consider the effect of interannual fluctuations in temperature. We find that the steady-state volume of an ice sheet is biased toward larger size if interannual temperature fluctuations are not taken into account in numerical modeling of the ice sheet. We illustrate this in a simple ice sheet model and find that the equilibrium ice volume is approximately 1 m SLE (meters sea level equivalent smaller when the simple model is forced with fluctuating temperatures as opposed to a stable climate. It is therefore important to consider the effect of interannual temperature fluctuations when designing long experiments such as paleo-spin-ups. We show how the magnitude of the potential bias can be quantified statistically. For recent simulations of the Greenland Ice Sheet, we estimate the bias to be 30 Gt yr−1 (24–59 Gt yr−1, 95 % credibility for a warming of 3 °C above preindustrial values, or 13 % (10–25, 95 % credibility of the present-day rate of ice loss. Models of the Greenland Ice Sheet show a collapse threshold beyond which the ice sheet becomes unsustainable. The proximity of the threshold will be underestimated if temperature fluctuations are not taken into account. We estimate the bias to be 0.12 °C (0.10–0.18 °C, 95 % credibility for a recent estimate of the threshold. In light of our findings it is important to gauge the extent to which this increased variability will influence the mass balance of the ice sheets.
Framework for Application of the Toxicity Equivalence ...
Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) are persistent contaminants found widely in the environment. Several of these compounds bioaccumulate in the tissues of fish, birds, and mammals and have been shown to cause mortality and adverse effects on reproduction, development, and the immune system. EPA has developed a framework intended to assist Agency scientists in using a method known as the toxicity equivalence methodology to evaluate the ecological risks of these chemicals. The methodology offers a means to derive a single exposure estimate from multiple chemical concentrations found in environmental mixtures so that risk assessors can consider their cumulative impacts. This framework helps to clarify this methodology’s strengths, limitations, and role within the broader context of ecological risk assessment.
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 7. Game Theory - Nash Equilibrium. P G Babu. General Article Volume 3 Issue 7 July 1998 pp 53- ... Author Affiliations. P G Babu1. Indira Gandhi Institute of Development Research Gen. A K Vaidya Marg Goregaon(East) Mumbai 400 065, India.
Understanding Thermal Equilibrium through Activities
Pathare, Shirish; Huli, Saurabhee; Nachane, Madhura; Ladage, Savita; Pradhan, Hemachandra
2015-01-01
Thermal equilibrium is a basic concept in thermodynamics. In India, this concept is generally introduced at the first year of undergraduate education in physics and chemistry. In our earlier studies (Pathare and Pradhan 2011 "Proc. episteme-4 Int. Conf. to Review Research on Science Technology and Mathematics Education" pp 169-72) we…
Equilibrium theory : A salient approach
Schalk, S.
1999-01-01
Whereas the neoclassical models in General Equilibrium Theory focus on the existence of separate commodities, this thesis regards 'bundles of trade' as the unit objects of exchange. Apart from commodities and commodity bundles in the neoclassical sense, the term `bundle of trade' includes, for
Incentives in Supply Function Equilibrium
DEFF Research Database (Denmark)
Vetter, Henrik
2014-01-01
The author analyses delegation in homogenous duopoly under the assumption that the firm-managers compete in supply functions. In supply function equilibrium, managers’ decisions are strategic complements. This reverses earlier findings in that the author finds that owners give managers incentives...
Risk premia in general equilibrium
DEFF Research Database (Denmark)
Posch, Olaf
solutions of dynamic stochastic general equilibrium models, including a novel solution with endogenous labor supply, to obtain closed-form expressions for the risk premium in production economies. We find that the curvature of the policy functions affects the risk premium through controlling the individual...
Estimation of Equivalent Damping Ratio using Friction Response Spectrum
渡邉, 鉄也; 鈴木, 浩平
2000-01-01
This report deals with the seismic response behavior of piping systems in industrial facilities such as petro-chemical, oil refinery and nuclear power plants. Piping is generally put on the supporting structures. Therefore, frictional vibration occurs between piping and supporting system during seismic excitation. Special attention is focused on this nonlinear frictional dynamic responses of piping systems due to frictional vibration appearing among piping and supporting devices. Mock-up pipi...
ROMANIC EQUIVALENTS FOR LATIN IDIOMS
Directory of Open Access Journals (Sweden)
Dr. Stefan DUMITRU
2010-11-01
Full Text Available In this study we set forth to present several of the most important aspects regarding the contrastive analysis of a well-defined number of Latin idioms in parallel with their Romanic counterparts (in French, Italian, Spanish and Romanian. Our intent was not to discover, in the Romanic space, all the equivalents of the phrases that form the corpus we work with, for reasons pertaining to material restrictions, but to discuss, based on a certain number of units, the different types of issues they may point to. The most important is to establish the relation between the idiomatic expressions in Latin and their correspondents in the above mentioned languages, regarding their inner form, their meaning and their structure.
Expanding the Interaction Equivalency Theorem
Directory of Open Access Journals (Sweden)
Brenda Cecilia Padilla Rodriguez
2015-06-01
Full Text Available Although interaction is recognised as a key element for learning, its incorporation in online courses can be challenging. The interaction equivalency theorem provides guidelines: Meaningful learning can be supported as long as one of three types of interactions (learner-content, learner-teacher and learner-learner is present at a high level. This study sought to apply this theorem to the corporate sector, and to expand it to include other indicators of course effectiveness: satisfaction, knowledge transfer, business results and return on expectations. A large Mexican organisation participated in this research, with 146 learners, 30 teachers and 3 academic assistants. Three versions of an online course were designed, each emphasising a different type of interaction. Data were collected through surveys, exams, observations, activity logs, think aloud protocols and sales records. All course versions yielded high levels of effectiveness, in terms of satisfaction, learning and return on expectations. Yet, course design did not dictate the types of interactions in which students engaged within the courses. Findings suggest that the interaction equivalency theorem can be reformulated as follows: In corporate settings, an online course can be effective in terms of satisfaction, learning, knowledge transfer, business results and return on expectations, as long as (a at least one of three types of interaction (learner-content, learner-teacher or learner-learner features prominently in the design of the course, and (b course delivery is consistent with the chosen type of interaction. Focusing on only one type of interaction carries a high risk of confusion, disengagement or missed learning opportunities, which can be managed by incorporating other forms of interactions.
Equivalence of recursive specifications in process algebra
A.J. van der Poorten (Alf); Y.S. Usenko (Yaroslav)
2001-01-01
textabstractWe define an equivalence relation on recursive specifications in process algebra that is model-independent and does not involve an explicit notion of solution. Then we extend this equivalence to the specification language $mu$CRL.
Equivalent damage of loads on pavements
CSIR Research Space (South Africa)
Prozzi, JA
2009-05-26
Full Text Available This report describes a new methodology for the determination of Equivalent Damage Factors (EDFs) of vehicles with multiple axle and wheel configurations on pavements. The basic premise of this new procedure is that "equivalent pavement response...
Behavioural equivalence for infinite systems - Partially decidable!
DEFF Research Database (Denmark)
Sunesen, Kim; Nielsen, Mogens
1996-01-01
languages with two generalizations based on traditional approaches capturing non-interleaving behaviour, pomsets representing global causal dependency, and locality representing spatial distribution of events. We first study equivalences on Basic Parallel Processes, BPP, a process calculus equivalent...
Non-Equilibrium Properties from Equilibrium Free Energy Calculations
Pohorille, Andrew; Wilson, Michael A.
2012-01-01
Calculating free energy in computer simulations is of central importance in statistical mechanics of condensed media and its applications to chemistry and biology not only because it is the most comprehensive and informative quantity that characterizes the eqUilibrium state, but also because it often provides an efficient route to access dynamic and kinetic properties of a system. Most of applications of equilibrium free energy calculations to non-equilibrium processes rely on a description in which a molecule or an ion diffuses in the potential of mean force. In general case this description is a simplification, but it might be satisfactorily accurate in many instances of practical interest. This hypothesis has been tested in the example of the electrodiffusion equation . Conductance of model ion channels has been calculated directly through counting the number of ion crossing events observed during long molecular dynamics simulations and has been compared with the conductance obtained from solving the generalized Nernst-Plank equation. It has been shown that under relatively modest conditions the agreement between these two approaches is excellent, thus demonstrating the assumptions underlying the diffusion equation are fulfilled. Under these conditions the electrodiffusion equation provides an efficient approach to calculating the full voltage-current dependence routinely measured in electrophysiological experiments.
Discovering Classes of Strongly Equivalent Logic Programs
Chen, Y.; Lin, F.
2011-01-01
In this paper we apply computer-aided theorem discovery technique to discover theorems about strongly equivalent logic programs under the answer set semantics. Our discovered theorems capture new classes of strongly equivalent logic programs that can lead to new program simplification rules that preserve strong equivalence. Specifically, with the help of computers, we discovered exact conditions that capture the strong equivalence between a rule and the empty set, between two rules, between t...
Dose Equivalents for Antipsychotic Drugs: The DDD Method.
Leucht, Stefan; Samara, Myrto; Heres, Stephan; Davis, John M
2016-07-01
Dose equivalents of antipsychotics are an important but difficult to define concept, because all methods have weaknesses and strongholds. We calculated dose equivalents based on defined daily doses (DDDs) presented by the World Health Organisation's Collaborative Center for Drug Statistics Methodology. Doses equivalent to 1mg olanzapine, 1mg risperidone, 1mg haloperidol, and 100mg chlorpromazine were presented and compared with the results of 3 other methods to define dose equivalence (the "minimum effective dose method," the "classical mean dose method," and an international consensus statement). We presented dose equivalents for 57 first-generation and second-generation antipsychotic drugs, available as oral, parenteral, or depot formulations. Overall, the identified equivalent doses were comparable with those of the other methods, but there were also outliers. The major strength of this method to define dose response is that DDDs are available for most drugs, including old antipsychotics, that they are based on a variety of sources, and that DDDs are an internationally accepted measure. The major limitations are that the information used to estimate DDDS is likely to differ between the drugs. Moreover, this information is not publicly available, so that it cannot be reviewed. The WHO stresses that DDDs are mainly a standardized measure of drug consumption, and their use as a measure of dose equivalence can therefore be misleading. We, therefore, recommend that if alternative, more "scientific" dose equivalence methods are available for a drug they should be preferred to DDDs. Moreover, our summary can be a useful resource for pharmacovigilance studies. © The Author 2016. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.
Classical or equilibrium thermodynamics: basic conceptual aspects
Directory of Open Access Journals (Sweden)
Luiz Augusto Calvo Tiritan
2008-08-01
Full Text Available The Classical or Equilibrium Thermodynamics is one of the most consolidated fields of Physics. It is synthesized by a well-known and self coherent knowledge structure. The essence of the Classical Thermodynamics theoretical structure consists of a set of natural laws that rule the macroscopic physical systems behavior. These laws were formulated based on observations generalizations and are mostly independent of any hypotheses concerning the microscopic nature of the matter. In general, the approaches established for the Classical Thermodynamics follow one of the following alternatives: the historical approach that describes chronologically the evolution of ideas, concepts and facts, and the postulational approach in which postulates are formulated but are not demonstrated a priori but can be confirmed a posteriori. In this work, a brief review of the pre-classical historical approach conceptual evolution is elaborated, from the beginning of the seventeenth century to the middle of the nineteenth century. As for this, the following themes are dealt with in an evolutionary and phenomenological way: heat nature, thermometry, calorimetry, Carnot’s heat engine, heat mechanical equivalent and the first and second laws. The Zeroth law that was formulated afterwards is included in the discussion.
Perrier, Jeremy; Zhou, Zhou; Dunn, Claire; Khadra, Ibrahim; Wilson, Clive G; Halbert, Gavin
2018-01-01
Upon oral administration the solubility of a drug in intestinal fluid is a key property influencing bioavailability. It is also recognised that simple aqueous solubility does not reflect intestinal solubility and to optimise in vitro investigations simulated intestinal media systems have been developed. Simulated intestinal media which can mimic either the fasted or fed state consists of multiple components each of which either singly or in combination may influence drug solubility, a property that can be investigated by a statistical design of experiment technique. In this study a design of experiment covering the full range from the lower limit of fasted to the upper limit of fed parameters and using a small number of experiments has been performed. The measured equilibrium solubility values are comparable with literature values for simulated fasted and fed intestinal fluids as well as human fasted and fed intestinal fluids. The equilibrium solubility data range is statistically equivalent to a combination of published fasted and fed design of experiment data in six (indomethacin, phenytoin, zafirlukast, carvedilol, fenofibrate and probucol) drugs with three (aprepitant, tadalafil and felodipine) drugs not equivalent. In addition the measured equilibrium solubility data sets were not normally distributed. Further studies will be required to determine the reasons for these results however it implies that a single solubility measurement without knowledge of the solubility distribution will be of limited value. The statistically significant media factors which promote equilibrium solubility (pH, sodium oleate and bile salt) were in agreement with published results but the number of determined significant factors and factor interactions was fewer in this study, lecithin for example did not influence solubility. This may be due to the reduction in statistical sensitivity from the lower number of experimental data points or the fact that using the full range will
Near-Nash equilibrium strategies for LQ differential games with inaccurate state information
Directory of Open Access Journals (Sweden)
2006-01-01
Full Text Available ε -Nash equilibrium or “near equilibrium” for a linear quadratic cost game is considered. Due to inaccurate state information, the standard solution for feedback Nash equilibrium cannot be applied. Instead, an estimation of the players' states is substituted into the optimal control strategies equation obtained for perfect state information. The magnitude of the ε in the ε -Nash equilibrium will depend on the quality of the estimation process. To illustrate this approach, a Luenberger-type observer is used in the numerical example to generate the players' state estimates in a two-player non-zero-sum LQ differential game.
Westerhoff, Hans V.; Lolkema, Juke S.; Otto, Roel; Hellingwerf, K
1982-01-01
Microbial growth is analyzed in terms of mosaic and phenomenological non-equilibrium thermodynamics. It turns out that already existing parameters devised to measure bacterial growth, such as YATP, µ, and Qsubstrate, have as thermodynamic equivalents flow ratio, output flow and input flow. With this
Equilibrium and Non-Equilibrium Condensation Phenomena in Tuneable 3D and 2D Bose Gases
2016-04-01
AFRL-AFOSR-UK-TR-2016-0009 Equilibrium and non- equilibrium condensation phenomena in tuneable 3D and 2D Bose gases Zoran Hadzibabic THE CHANCELLOR...31-Aug-2015 4. TITLE AND SUBTITLE Equilibrium and non- equilibrium condensation phenomena in tuneable 3D and 2D Bose gases 5a. CONTRACT NUMBER... equilibrium and non- equilibrium many-body phenomena, trapping ultracold atomic gases in different geometries including both 3 and 2 spatial dimensions
Protonation Equilibrium of Linear Homopolyacids
Directory of Open Access Journals (Sweden)
Požar J.
2015-07-01
Full Text Available The paper presents a short summary of investigations dealing with protonation equilibrium of linear homopolyacids, in particularly those of high charge density. Apart from the review of experimental results which can be found in the literature, a brief description of theoretical models used in processing the dependence of protonation constants on monomer dissociation degree and ionic strength is given (cylindrical model based on Poisson-Boltzmann equation, cylindrical Stern model, the models according to Ising, Högfeldt, Mandel and Katchalsky. The applicability of these models regarding the polyion charge density, electrolyte concentration and counterion type is discussed. The results of Monte Carlo simulations of protonation equilibrium are also briefly mentioned. In addition, frequently encountered errors connected with calibration of of glass electrode and the related unreliability of determined protonation constants are pointed out.
The Rigorous Evaluation of Spectrophotometric Data to Obtain an Equilibrium Constant.
Long, John R.; Drago, Russell S.
1982-01-01
Most students do not know how to determine the equilibrium constant and estimate the error in it from spectrophotometric data that contain experimental errors. This "dry-lab" experiment describes a method that may be used to determine the "best-fit" value of the 1:1 equilibrium constant to spectrophotometric data. (Author/JN)
Carbon footprint calculation model for the Mexican food equivalent system
Directory of Open Access Journals (Sweden)
Salvador Ruiz Cerrillo
2017-06-01
Full Text Available Introduction: the impact environment trough the anthropogenic action has been contributed to the fast production of greenhouse gases effect (GHG, a way to estimate the quantity of these substances is the carbon footprint (CF, nowadays it does not exist enough models for the calculation of food carbon footprint. Objective: the aim of this study was to design a calculation model for the measurement of the carbon footprint on the Mexican food equivalent system. Methods: it was about a retrospective study, a bibliographic review was made with original and review articles in different specialized researchers, there were included publications in English and Spanish, also published from 2000 to 2016. Results: a reference table was proposed for the food carbon footprint calculation on the Mexican food equivalent system trough the carbon intensity indicator, which is determined by the grams of emissions equivalents of carbon dioxide (CO2 in relation with the energetic contribution of each food equivalent. Conclusion: in a conclusion manner, estimating food carbon footprint is still a challenge, mean while the calculation models proposal is important to estimate the production of GHG trough a more sustainable food system.
Nash Equilibrium in Social Media
Salehisadaghiani, Farzad
2017-01-01
In this work, we investigate an application of a Nash equilibrium seeking algorithm in a social network. In a networked game each player (user) takes action in response to other players' actions in order to decrease (increase) his cost (profit) in the network. We assume that the players' cost functions are not necessarily dependent on the actions of all players. This is due to better mimicking the standard social media rules. A communication graph is defined for the game through which players...
An introduction to equilibrium thermodynamics
Morrill, Bernard; Hartnett, James P; Hughes, William F
1973-01-01
An Introduction to Equilibrium Thermodynamics discusses classical thermodynamics and irreversible thermodynamics. It introduces the laws of thermodynamics and the connection between statistical concepts and observable macroscopic properties of a thermodynamic system. Chapter 1 discusses the first law of thermodynamics while Chapters 2 through 4 deal with statistical concepts. The succeeding chapters describe the link between entropy and the reversible heat process concept of entropy; the second law of thermodynamics; Legendre transformations and Jacobian algebra. Finally, Chapter 10 provides a
Ascending auctions and Walrasian equilibrium
Ben-Zwi, Oren; Lavi, Ron; Newman, Ilan
2013-01-01
We present a family of submodular valuation classes that generalizes gross substitute. We show that Walrasian equilibrium always exist for one class in this family, and there is a natural ascending auction which finds it. We prove some new structural properties on gross-substitute auctions which, in turn, show that the known ascending auctions for this class (Gul-Stacchetti and Ausbel) are, in fact, identical. We generalize these two auctions, and provide a simple proof that they terminate in...
Punctuated equilibrium comes of age
Gould, Stephan Jay; Eldredge, Niles
1993-11-01
The intense controversies that surrounded the youth of punctuated equilibrium have helped it mature to a useful extension of evolutionary theory. As a complement to phyletic gradualism, its most important implications remain the recognition of stasis as a meaningful and predominant pattern within the history of species, and in the recasting of macroevolution as the differential success of certain species (and their descendants) within clades.
Gibbs free energy and integrability of continuum models for granular media at equilibrium
Varsakelis, C.
2015-05-01
In this letter, we address the problem of the integrability of a continuum model for granular media at equilibrium. By the means of a formal integrability analysis, we show that the equilibrium limit of such models can be cast into a gradient equation with zero right-hand side. In turn, this implies that the model of interest is inherently Frobenius integrable, in the absence of additional compatibility conditions. Moreover, the quantity inside the gradient is identified with the granular material's Gibbs free energy. Consequently, the integrability for the model at hand is equivalent to setting the Gibbs free energy of the granular material constant throughout the domain. In other words, integrability is equivalent to the definition of equilibrium employed in statistical physics.
Local equilibrium in bird flocks
Mora, Thierry; Walczak, Aleksandra M.; Del Castello, Lorenzo; Ginelli, Francesco; Melillo, Stefania; Parisi, Leonardo; Viale, Massimiliano; Cavagna, Andrea; Giardina, Irene
2016-12-01
The correlated motion of flocks is an example of global order emerging from local interactions. An essential difference with respect to analogous ferromagnetic systems is that flocks are active: animals move relative to each other, dynamically rearranging their interaction network. This non-equilibrium characteristic has been studied theoretically, but its impact on actual animal groups remains to be fully explored experimentally. Here, we introduce a novel dynamical inference technique, based on the principle of maximum entropy, which accommodates network rearrangements and overcomes the problem of slow experimental sampling rates. We use this method to infer the strength and range of alignment forces from data of starling flocks. We find that local bird alignment occurs on a much faster timescale than neighbour rearrangement. Accordingly, equilibrium inference, which assumes a fixed interaction network, gives results consistent with dynamical inference. We conclude that bird orientations are in a state of local quasi-equilibrium over the interaction length scale, providing firm ground for the applicability of statistical physics in certain active systems.
An Equivalent Fracture Modeling Method
Li, Shaohua; Zhang, Shujuan; Yu, Gaoming; Xu, Aiyun
2017-12-01
3D fracture network model is built based on discrete fracture surfaces, which are simulated based on fracture length, dip, aperture, height and so on. The interesting area of Wumishan Formation of Renqiu buried hill reservoir is about 57 square kilometer and the thickness of target strata is more than 2000 meters. In addition with great fracture density, the fracture simulation and upscaling of discrete fracture network model of Wumishan Formation are very intense computing. In order to solve this problem, a method of equivalent fracture modeling is proposed. First of all, taking the fracture interpretation data obtained from imaging logging and conventional logging as the basic data, establish the reservoir level model, and then under the constraint of reservoir level model, take fault distance analysis model as the second variable, establish fracture density model by Sequential Gaussian Simulation method. Increasing the width, height and length of fracture, at the same time decreasing its density in order to keep the similar porosity and permeability after upscaling discrete fracture network model. In this way, the fracture model of whole interesting area can be built within an accepted time.
Gas phase equilibrium structure of histamine.
Tikhonov, Denis S; Rykov, Anatolii N; Grikina, Olga E; Khaikin, Leonid S
2016-02-17
The first gas electron diffraction (GED) experiment for histamine was carried out. The equilibrium structure of histamine in the gas phase was determined on the basis of the data obtained. The refinement was also supported by the rotational constants obtained in previous studies [B. Vogelsanger, et al., J. Am. Chem. Soc., 1991, 113, 7864-7869; P. Godfrey, et al., J. Am. Chem. Soc., 1998, 120, 10724-10732] and quantum chemical calculations. The proposed mechanism of tautomerization by simultaneous intermolecular transfer of hydrogens in a histamine dimer helps to explain the distribution of tautomers in different experiments. The estimations of the conformational interconversion times provided the explanation for the absence of some conformers in the rotational spectroscopy experiments.
EQQYAC: Program for determining geothermal reservoir chemical equilibrium
Barragan, R. M.; Nieva, D. G.
The computer program EQQYAC calculates the equilibrium distribution of inorganic aqueous ion species in geothermal reservoirs, using the chemical composition of discharged fluids and in situ physical measurements. The program, written in FORTRAN IV for a VAX/11-780 computer system, is suited to handle data from wells that produce both steam and liquid phase water. The program has been successfully used with data of wells from Los Azufres geothermal field. EQQYAC estimates the reservoir steam fraction, (excess steam), that could be present in the total discharge fluid. In order to carry out this calculation, the Fischer-Tropsch reaction is assumed to be at equilibrium at reservoir conditions. The deviation of the concentrations of the participant ions from the expected values at equilibrium, are considered due to the excess steam. This program also may be used to study chemical changes in the deep fluid as a consequence of reservoir boiling.
Equilibrium and thermodynamics of azo dyes biosorption onto Spirulina platensis
Directory of Open Access Journals (Sweden)
G. L. Dotto
2013-03-01
Full Text Available The equilibrium and thermodynamics of azo dye (tartrazine and allura red biosorption onto Spirulina platensis biomass were investigated. The equilibrium curves were obtained at 298, 308, 318 and 328 K, and four isotherm models were fitted the experimental data. Biosorption thermodynamic parameters (ΔG, ΔH and ΔS were estimated. The results showed that the biosorption was favored by a temperature decrease. For both dyes, the Sips model was the best to represent the equilibrium experimental data (R²>0.99 and ARE<5.0% and the maximum biosorption capacities were 363.2 and 468.7 mg g-1 for tartrazine and allura red, respectively, obtained at 298 K. The negative values of ΔG and ΔH showed that the biosorption of both dyes was spontaneous, favorable and exothermic. The positive values of ΔS suggested that the system disorder increases during the biosorption process.
An equilibrium-conserving taxation scheme for income from capital
Tempere, Jacques
2018-02-01
Under conditions of market equilibrium, the distribution of capital income follows a Pareto power law, with an exponent that characterizes the given equilibrium. Here, a simple taxation scheme is proposed such that the post-tax capital income distribution remains an equilibrium distribution, albeit with a different exponent. This taxation scheme is shown to be progressive, and its parameters can be simply derived from (i) the total amount of tax that will be levied, (ii) the threshold selected above which capital income will be taxed and (iii) the total amount of capital income. The latter can be obtained either by using Piketty's estimates of the capital/labor income ratio or by fitting the initial Pareto exponent. Both ways moreover provide a check on the amount of declared income from capital.
The Geometry of Finite Equilibrium Datasets
DEFF Research Database (Denmark)
Balasko, Yves; Tvede, Mich
We investigate the geometry of finite datasets defined by equilibrium prices, income distributions, and total resources. We show that the equilibrium condition imposes no restrictions if total resources are collinear, a property that is robust to small perturbations. We also show that the set...... of equilibrium datasets is pathconnected when the equilibrium condition does impose restrictions on datasets, as for example when total resources are widely non collinear....
Accelerating Multiagent Reinforcement Learning by Equilibrium Transfer.
Hu, Yujing; Gao, Yang; An, Bo
2015-07-01
An important approach in multiagent reinforcement learning (MARL) is equilibrium-based MARL, which adopts equilibrium solution concepts in game theory and requires agents to play equilibrium strategies at each state. However, most existing equilibrium-based MARL algorithms cannot scale due to a large number of computationally expensive equilibrium computations (e.g., computing Nash equilibria is PPAD-hard) during learning. For the first time, this paper finds that during the learning process of equilibrium-based MARL, the one-shot games corresponding to each state's successive visits often have the same or similar equilibria (for some states more than 90% of games corresponding to successive visits have similar equilibria). Inspired by this observation, this paper proposes to use equilibrium transfer to accelerate equilibrium-based MARL. The key idea of equilibrium transfer is to reuse previously computed equilibria when each agent has a small incentive to deviate. By introducing transfer loss and transfer condition, a novel framework called equilibrium transfer-based MARL is proposed. We prove that although equilibrium transfer brings transfer loss, equilibrium-based MARL algorithms can still converge to an equilibrium policy under certain assumptions. Experimental results in widely used benchmarks (e.g., grid world game, soccer game, and wall game) show that the proposed framework: 1) not only significantly accelerates equilibrium-based MARL (up to 96.7% reduction in learning time), but also achieves higher average rewards than algorithms without equilibrium transfer and 2) scales significantly better than algorithms without equilibrium transfer when the state/action space grows and the number of agents increases.
The geometry of finite equilibrium sets
DEFF Research Database (Denmark)
Balasko, Yves; Tvede, Mich
2009-01-01
We investigate the geometry of finite datasets defined by equilibrium prices, income distributions, and total resources. We show that the equilibrium condition imposes no restrictions if total resources are collinear, a property that is robust to small perturbations. We also show that the set...... of equilibrium datasets is pathconnected when the equilibrium condition does impose restrictions on datasets, as for example when total resources are widely noncollinear....
Validity of the Aluminum Equivalent Approximation in Space Radiation Shielding
Badavi, Francis F.; Adams, Daniel O.; Wilson, John W.
2009-01-01
The origin of the aluminum equivalent shield approximation in space radiation analysis can be traced back to its roots in the early years of the NASA space programs (Mercury, Gemini and Apollo) wherein the primary radiobiological concern was the intense sources of ionizing radiation causing short term effects which was thought to jeopardize the safety of the crew and hence the mission. Herein, it is shown that the aluminum equivalent shield approximation, although reasonably well suited for that time period and to the application for which it was developed, is of questionable usefulness to the radiobiological concerns of routine space operations of the 21 st century which will include long stays onboard the International Space Station (ISS) and perhaps the moon. This is especially true for a risk based protection system, as appears imminent for deep space exploration where the long-term effects of Galactic Cosmic Ray (GCR) exposure is of primary concern. The present analysis demonstrates that sufficiently large errors in the interior particle environment of a spacecraft result from the use of the aluminum equivalent approximation, and such approximations should be avoided in future astronaut risk estimates. In this study, the aluminum equivalent approximation is evaluated as a means for estimating the particle environment within a spacecraft structure induced by the GCR radiation field. For comparison, the two extremes of the GCR environment, the 1977 solar minimum and the 2001 solar maximum, are considered. These environments are coupled to the Langley Research Center (LaRC) deterministic ionized particle transport code High charge (Z) and Energy TRaNsport (HZETRN), which propagates the GCR spectra for elements with charges (Z) in the range I aluminum equivalent approximation for a good polymeric shield material such as genetic polyethylene (PE). The shield thickness is represented by a 25 g/cm spherical shell. Although one could imagine the progression to greater
Open problems in non-equilibrium physics
Energy Technology Data Exchange (ETDEWEB)
Kusnezov, D.
1997-09-22
The report contains viewgraphs on the following: approaches to non-equilibrium statistical mechanics; classical and quantum processes in chaotic environments; classical fields in non-equilibrium situations: real time dynamics at finite temperature; and phase transitions in non-equilibrium conditions.
The concept of equilibrium in organization theory
Gazendam, Henk W.M.
1997-01-01
Many organization theories consist of an interpretation frame and an idea about the ideal equilibrium state. This article explains how the equilibrium concept is used in four organization theories: the theories of Fayol, Mintzberg, Morgan, and Volberda. Equilibrium can be defined as balance, fit or
The concept of equilibrium in organization theory
Gazendam, H.W.M.
1998-01-01
Many organization theories consist of an interpretation frame and an idea about the ideal equilibrium state. This article explains how the equilibrium concept is used in four organization theories: the theories of Fayol, Mintzberg, Morgan, and Volberda. Equilibrium can be defined as balance, fit or
Directory of Open Access Journals (Sweden)
Kévin Martial Tsapi Tchoupou
Full Text Available Abstract This paper is concerned with the fatigue prediction models for estimating the multiaxial fatigue limit. An equivalent loading approach with zero out-of-phase angles intended for fatigue limit evaluation under multiaxial loading is used. Based on experimental data found in literatures, the equivalent stress is validated in Crossland and Sines criteria and predictions compared to the predictions of existing multiaxial fatigue; results over 87 experimental items show that the equivalent stress approach is very efﬁcient.
A non-equilibrium equation-of-motion approach to quantum transport utilizing projection operators.
Ochoa, Maicol A; Galperin, Michael; Ratner, Mark A
2014-11-12
We consider a projection operator approach to the non-equilibrium Green function equation-of-motion (PO-NEGF EOM) method. The technique resolves problems of arbitrariness in truncation of an infinite chain of EOMs and prevents violation of symmetry relations resulting from the truncation (equivalence of left- and right-sided EOMs is shown and symmetry with respect to interchange of Fermi or Bose operators before truncation is preserved). The approach, originally developed by Tserkovnikov (1999 Theor. Math. Phys. 118 85) for equilibrium systems, is reformulated to be applicable to time-dependent non-equilibrium situations. We derive a canonical form of EOMs, thus explicitly demonstrating a proper result for the non-equilibrium atomic limit in junction problems. A simple practical scheme applicable to quantum transport simulations is formulated. We perform numerical simulations within simple models and compare results of the approach to other techniques and (where available) also to exact results.
On Non-Equilibrium Thermodynamics of Space-Time and Quantum Gravity
Munkhammar, Joakim
2015-01-01
Based on recent results from general relativistic statistical mechanics and black hole information transfer limits a space-time entropy-action equivalence is proposed as a generalization of the holographic principle. With this conjecture, the action principle can be replaced by the second law of thermodynamics, and for the Einstein-Hilbert action the Einstein field equations are conceptually the result of thermodynamic equilibrium. For non-equilibrium situations Jaynes' information-theoretic approach to maximum entropy production is adopted instead of the second law of thermodynamics. As it turns out, for appropriate choices of constants quantum gravity is obtained. For the special case of a free particle the Bekenstein-Verlinde entropy-to-displacement relation of holographic gravity, and thus the traditional holographic principle, emerges. Although Jacobson's original thermodynamic equilibrium approach proposed that gravity might not necessarily be quantized, this particular non-equilibrium treatment might r...
Directory of Open Access Journals (Sweden)
Annamaria Barbagallo
2012-01-01
Full Text Available The paper is concerned with the variational formulation of the oligopolistic market equilibrium problem in presence of both production and demand excesses. In particular, we generalize a previous model in which the authors, instead, considered only the problem with production excesses, by allowing also the presence of demand excesses. First we examine the equilibrium conditions in terms of the well-known dynamic Cournot-Nash principle. Next, the equilibrium conditions will be expressed in terms of Lagrange multipliers by means of the infinite dimensional duality theory. Then, we show the equivalence between the two conditions that are both expressed by an appropriate evolutionary variational inequality. Moreover, thanks to the variational formulation, some existence and regularity results for equilibrium solutions are proved. At last, a numerical example, which illustrates the features of the problem, is provided.
Ambient dose equivalents in TGFs
Celestin, Sebastien; Pincon, Jean-Louis; Trompier, Francois
2017-04-01
Terrestrial gamma-ray flashes (TGFs) are bursts of high-energy photons originating from the Earth's atmosphere in association with thunderstorm activity [e.g., Briggs et al., JGR, 118, 3805, 2013]. TGFs are associated with initial propagation stages of intracloud lightning, which represent the most frequent type of lightning discharges [e.g., Cummer et al., GRL, 42, 7792, 2015, and references therein]. TGFs are known to be produced inside common thunderclouds [e.g., Splitt et al., JGR, 115, A00E38, 2010] typically at altitudes ranging from 10 to 14 km [e.g., Cummer et al., GRL, 41, 8586, 2014]. The global TGF occurrence rate is estimated to be 400,000 per year concerning TGFs detectable by Fermi-GBM (Gamma ray Burst Monitor) [Briggs et al., 2013], but detailed analysis of satellite measurements [Østgaard et al., JGR, 117, A03327, 2012] and theoretical studies [Celestin et al., JGR, 120, 10712, 2015] suggest that it cannot be excluded that TGFs represent a part of a regular process taking place during the propagation of lightning discharges. It is important to assess the risk induced by TGFs for airline passengers and crews on board aircraft approaching thunderstorms. Dwyer et al. [JGR, 115, D09206, 2010] have estimated that if an aircraft were to find itself in the source electron beam giving rise to a TGF, passengers and crews might receive effective radiation doses above the regulatory limit depending on the beam diameter. Moreover, Tavani et al. [Nat. Hazards Earth Syst. Sci., 13, 1127, 2013] concluded that TGF-associated neutrons produced by photonuclear reactions would cause serious hazard on the aircraft avionics. In this work, we will present detailed simulation-based estimations of effective doses received by humans that would be irradiated by TGFs for various production altitudes and distances from the TGF source.
Silverberg, Lee J.; Raff, Lionel M.
2015-01-01
Thermodynamic spontaneity-equilibrium criteria require that in a single-reaction system, reactions in either the forward or reverse direction at equilibrium be nonspontaneous. Conversely, the concept of dynamic equilibrium holds that forward and reverse reactions both occur at equal rates at equilibrium to the extent allowed by kinetic…
Existence of collateral Equilibrium without survival assumption
Directory of Open Access Journals (Sweden)
Jaime Orrillo
2011-03-01
Full Text Available This paper shows the existence of a collateral equilibrium without assuming any hypotheses on the strict positivity, be they individual initial endowments, including the ex post initial endowments, or aggregated initial endowments. Because of dropping the strict positivity of social initial endowment we fail to get an equilibrium. Instead, we get a quasi-equilibrium. Then, appealing to the concept of irreducibility (introduced by McKenzie in 1959 which is adapted to the collateral model, we show that the quasi-equilibrium is indeed a legitime equilibrium.
[Hardy-Weinberg equilibrium in genetic epidemiology].
Liu, Hong; Hu, Yonghua
2010-01-01
Hardy-Weinberg equilibrium test is the base of genetic epidemiology. The new methods for Hardy-Weinberg equilibrium test involve: X chromosome-linked single nucleotide polymorphism Hardy-Weinberg test, inbreeding coefficient (F) test, an incomplete enumeration algorithm for an exact test of Hardy-Weinberg proportions with multiple alleles, and graphical tests for Hardy-Weinberg equilibrium based on the ternary plot. It is necessary to conduct Hardy-Weinberg equilibrium test in genetic epidemiology studies and adjust the associations as deviation of Hardy-Weinberg equilibrium occurs.
The effective theory of Borel equivalence relations
DEFF Research Database (Denmark)
Fokina, E.B.; Friedman, S.-D.; Törnquist, Asger Dag
2010-01-01
equality on ω is above equality on P (ω), the power set of ω, and any Borel equivalence relation strictly above equality on the reals is above equality modulo finite on P (ω). In this article we examine the effective content of these and related results by studying effectively Borel equivalence relations......The study of Borel equivalence relations under Borel reducibility has developed into an important area of descriptive set theory. The dichotomies of Silver [20] and Harrington, Kechris and Louveau [6] show that with respect to Borel reducibility, any Borel equivalence relation strictly above...... under effectively Borel reducibility. The resulting structure is complex, even for equivalence relations with finitely many equivalence classes. However use of Kleene's O as a parameter is sufficient to restore the picture from the noneffective setting. A key lemma is that of the existence of two...
The Complexity of Identifying Large Equivalence Classes
DEFF Research Database (Denmark)
Skyum, Sven; Frandsen, Gudmund Skovbjerg; Miltersen, Peter Bro
1999-01-01
We prove that at least 3k−4/k(2k−3)(n/2) – O(k)equivalence tests and no more than 2/k (n/2) + O(n) equivalence tests are needed in the worst case to identify the equivalence classes with at least k members in set of n elements. The upper bound is an improvement by a factor 2 compared to known res...
On the equivalence of local and global area-constraint formulations for lipid bilayer vesicles
Dharmavaram, Sanjay; Healey, Timothy J.
2015-10-01
Lipid bilayer membranes are commonly modeled as area-preserving fluid surfaces that resist bending. There appear to be two schools of thought in the literature concerning the actual area constraint. In some works the total or global area of the vesicle is a prescribed constant, while in others the local area ratio is assigned to unity. In this work we demonstrate the equivalence of these ostensibly distinct approaches in the specific case when the equilibrium configuration is a smooth, closed surface of genus zero. We accomplish this in the context of the Euler-Lagrange equilibrium equations, constraint equations and the second variation with admissibility conditions, for a broad class of models—including the phase-field type. In particular, the two formulations have equivalent equilibria characterized by the same local-energy properties.
Thermalization and Return to Equilibrium on Finite Quantum Lattice Systems
Farrelly, Terry; Brandão, Fernando G. S. L.; Cramer, Marcus
2017-04-01
Thermal states are the bedrock of statistical physics. Nevertheless, when and how they actually arise in closed quantum systems is not fully understood. We consider this question for systems with local Hamiltonians on finite quantum lattices. In a first step, we show that states with exponentially decaying correlations equilibrate after a quantum quench. Then, we show that the equilibrium state is locally equivalent to a thermal state, provided that the free energy of the equilibrium state is sufficiently small and the thermal state has exponentially decaying correlations. As an application, we look at a related important question: When are thermal states stable against noise? In other words, if we locally disturb a closed quantum system in a thermal state, will it return to thermal equilibrium? We rigorously show that this occurs when the correlations in the thermal state are exponentially decaying. All our results come with finite-size bounds, which are crucial for the growing field of quantum thermodynamics and other physical applications.
21 CFR 26.9 - Equivalence determination.
2010-04-01
... RECOGNITION OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL DEVICE QUALITY SYSTEM AUDIT REPORTS... Specific Sector Provisions for Pharmaceutical Good Manufacturing Practices § 26.9 Equivalence determination...
21 CFR 26.6 - Equivalence assessment.
2010-04-01
... OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL DEVICE QUALITY SYSTEM AUDIT REPORTS... Specific Sector Provisions for Pharmaceutical Good Manufacturing Practices § 26.6 Equivalence assessment...
The geometry of structural equilibrium.
McRobie, Allan
2017-03-01
Building on a long tradition from Maxwell, Rankine, Klein and others, this paper puts forward a geometrical description of structural equilibrium which contains a procedure for the graphic analysis of stress resultants within general three-dimensional frames. The method is a natural generalization of Rankine's reciprocal diagrams for three-dimensional trusses. The vertices and edges of dual abstract 4-polytopes are embedded within dual four-dimensional vector spaces, wherein the oriented area of generalized polygons give all six components (axial and shear forces with torsion and bending moments) of the stress resultants. The relevant quantities may be readily calculated using four-dimensional Clifford algebra. As well as giving access to frame analysis and design, the description resolves a number of long-standing problems with the incompleteness of Rankine's description of three-dimensional trusses. Examples are given of how the procedure may be applied to structures of engineering interest, including an outline of a two-stage procedure for addressing the equilibrium of loaded gridshell rooves.
The geometry of structural equilibrium
2017-01-01
Building on a long tradition from Maxwell, Rankine, Klein and others, this paper puts forward a geometrical description of structural equilibrium which contains a procedure for the graphic analysis of stress resultants within general three-dimensional frames. The method is a natural generalization of Rankine’s reciprocal diagrams for three-dimensional trusses. The vertices and edges of dual abstract 4-polytopes are embedded within dual four-dimensional vector spaces, wherein the oriented area of generalized polygons give all six components (axial and shear forces with torsion and bending moments) of the stress resultants. The relevant quantities may be readily calculated using four-dimensional Clifford algebra. As well as giving access to frame analysis and design, the description resolves a number of long-standing problems with the incompleteness of Rankine’s description of three-dimensional trusses. Examples are given of how the procedure may be applied to structures of engineering interest, including an outline of a two-stage procedure for addressing the equilibrium of loaded gridshell rooves. PMID:28405361
The equilibrium of overpressurized polytropes
Huré, J.-M.; Hersant, F.; Nasello, G.
2018-03-01
We investigate the impact of an external pressure on the structure of self-gravitating polytropes for axially symmetric ellipsoids and rings. The confinement of the fluid by photons is accounted for through a boundary condition on the enthalpy H. Equilibrium configurations are determined numerically from a generalized `self-consistent-field' method. The new algorithm incorporates an intraloop re-scaling operator R(H), which is essential for both convergence and getting self-normalized solutions. The main control parameter is the external-to-core enthalpy ratio. In the case of uniform rotation rate and uniform surrounding pressure, we compute the mass, the volume, the rotation rate and the maximum enthalpy. This is repeated for a few polytropic indices, n. For a given axial ratio, overpressurization globally increases all output quantities, and this is more pronounced for large n. Density profiles are flatter than in the absence of an external pressure. When the control parameter asymptotically tends to unity, the fluid converges towards the incompressible solution, whatever the index, but becomes geometrically singular. Equilibrium sequences, obtained by varying the axial ratio, are built. States of critical rotation are greatly exceeded or even disappear. The same trends are observed with differential rotation. Finally, the typical response to a photon point source is presented. Strong irradiation favours sharp edges. Applications concern star-forming regions and matter orbiting young stars and black holes.
FORWARDER DEPRICIATION ANALYSIS APPLIED TO EQUIVALENT UNIFORM ANNUAL COST
DANILO SIMÕES; RICARDO GHANTOUS CERVI; PAULO TORRES FENNER
2013-01-01
Depreciation is considered a necessary fixed cost to replace a machinery or goods at the end of its useful life thus interfering directly on the Equivalent Annual Cost (EAC). This paper aimed at analyzing different methods used to calculate depreciation over the useful economic life of a Forwarder, a machine used in eucalyptus harvesting process, evaluating the influence of such methods in estimating EAC. Five depreciation methods were evaluated: Straight-line, Declining Balanc...
Electricity market equilibrium based on conjectural variations
Energy Technology Data Exchange (ETDEWEB)
Diaz, Cristian A.; Villar, Jose; Campos, Fco. Alberto; Reneses, Javier [Institute for Research in Technology, Technical School of Engineering, Comillas Pontifical University, Madrid 28015 (Spain)
2010-12-15
Many of the models used for the representation of the generation companies' behavior in oligopolistic electricity markets are based on conjectural variation equilibria, which are a generalization of the classic Cournot approach. However, one of the main drawbacks of these approaches is the complexity of assigning adequate values to the conjectures, which can dramatically affect the results obtained from these models. This paper reviews and analyses the main formulations of conjectural equilibria applied to electricity markets. The paper shows how these different formulations are equivalent, and presents the relationships among the conjectures they use. Finally, it presents a brief overview on the main methods to estimate or compute the conjectures of these types of models. (author)
Inferring patterns of migration from gene frequencies under equilibrium conditions.
Tufto, J; Engen, S; Hindar, K
1996-12-01
A new maximum likelihood method to simultaneously estimate the parameters of any migration pattern from gene frequencies in stochastic equilibrium is developed, based on a model of multivariate genetic drift in a subdivided population. Motivated by simulations of this process in the simplified case of two subpopulations, problems related to the nuisance parameter q, the equilibrium gene frequency, are eliminated by conditioning on the observed mean gene frequency. The covariance matrix of this conditional distribution is calculated by constructing an abstract process that mimics the behavior of the original process in the subspace of interest. The approximation holds as long as there is limited differentiation between subpopulations. The bias and variance of estimates of long-range and short-range migration in a finite stepping stone model are evaluated by fitting the model to simulated data with known values of the parameters. Possible ecological extensions of the model are discussed.
Modeling equilibrium Fe isotope fractionation
Anbar, A.; Jarzecki, A.; Spiro, T.
2003-04-01
Research into the stable isotope biogeochemistry of Fe and other transition metals has been driven primarily by analytical innovations which have revealed significant isotope effects in nature and the laboratory. Further development of these new isotope systems requires complementary theoretical research to guide analytical efforts. The results of the first such studies show some discrepancies with experiments. For example, Johnson et al. (2002) report an experimentally-determined 56Fe/54Fe equilibrium fractionation factor between Fe(II) and Fe(III) aquo complexes of ˜1.0025. This effect is ˜50% smaller than predicted theoretically by Schauble et al. (2001). It is important to resolve such discrepancies. Equilibrium isotope fractionation factors can be predicted from vibrational spectroscopic data of isotopically-substituted complexes, or from theoretical predictions of some or all of these frequencies obtained using force field models. The pioneering work of Schauble et al. (2001) utilized a modified Urey-Bradley force field (MUBFF) model. This approach is limiting in at least three ways: First, it is not ab initio, requiring as input some measured vibrational frequencies. Such data are not always available, or may have significant uncertainties. Second, the MUBFF does not include potentially important effects of solvent interaction. Third, because it makes certain assumptions about molecular symmetry, the MUBFF-based approach is not able to model the spectra of mixed-ligand complexes. To address these limitations, we are evaluating the use of density functional theory (DFT) as an ab initio method to predict vibrational frequencies of isotopically-substituted complexes and, hence, equilibrium fractionation factors. In a preliminary examination of the frequency shift upon isotope substitution of the bending and asymmetric stretching modes of the tetrahedral FeCl_42- complex, we find substantial differences between MUBFF and DFT predictions. Results for other Fe
Thermodynamic equilibrium at heterogeneous pressure
Vrijmoed, Johannes C.; Podladchikov, Yuri Y.
2014-05-01
Recent advances in metamorphic petrology point out the importance of grain-scale pressure variations in high-temperature metamorphic rocks. Pressures derived from chemical zonation using unconventional geobarometry based on equal chemical potentials fit mechanically feasible pressure variations. Here a thermodynamic equilibrium method is presented that predicts chemical zoning as a result of pressure variations by Gibbs energy minimization. Equilibrium thermodynamic prediction of the chemical zoning in the case of pressure heterogeneity is done by constraint Gibbs minimization using linear programming techniques. Compositions of phases considered in the calculation are discretized into 'pseudo-compounds' spanning the entire compositional space. Gibbs energies of these discrete compounds are generated for a given range and resolution of pressures for example derived by barometry or from mechanical model predictions. Gibbs energy minimization is subsequently performed considering all compounds of different composition and pressure. In addition to constraining the system composition a certain proportion of the system is constraint at a specified pressure. Input pressure variations need to be discretized and each discrete pressure defines an additional constraint for the minimization. The proportion of the system at each different pressure is equally distributed over the number of input pressures. For example if two input pressures P1 and P2 are specified, two constraints are added: 50 percent of the system is constraint at P1 while the remaining 50 percent is constraint at P2. The method has been tested for a set of 10 input pressures obtained by Tajčmanová et al. (2014) using their unconventional geobarometry method in a plagioclase rim around kyanite. Each input pressure is added as constraint to the minimization (1/10 percent of the system for each discrete pressure). Constraining the system composition to the average composition of the plagioclase rim
2010-10-01
...) INSPECTION AND CERTIFICATION International Convention for Safety of Life at Sea, 1974, as Amended (SOLAS) § 176.930 Equivalents. As outlined in Chapter I (General Provisions) Regulation 5, of SOLAS, the... required by SOLAS regulations if satisfied that such equivalent is at least as effective as that required...
2010-10-01
... International Convention for Safety of Life at Sea, 1974, as Amended (SOLAS) § 115.930 Equivalents. In accordance with Chapter I (General Provisions) Regulation 5, of SOLAS, the Commandant may accept an... the SOLAS regulations if satisfied that such equivalent is at least as effective as that required by...
Flow equivalence and isotopy for subshifts
DEFF Research Database (Denmark)
Boyle, Mike; Carlsen, Toke Meier; Eilers, Søren
2017-01-01
We study basic properties of flow equivalence on one-dimensional compact metric spaces with a particular emphasis on isotopy in the group of (self-) flow equivalences on such a space. In particular, we show that such an orbit-preserving map is not always an isotopy, but that this always is the case...
What is Metaphysical Equivalence? | Miller | Philosophical Papers
African Journals Online (AJOL)
In this paper I argue that if we are judiciously to resolve disputes about whether theories are equivalent or not, we need to develop testable criteria that will give us epistemic access to the obtaining of the relation of metaphysical equivalence holding between those theories. I develop such 'diagnostic' criteria. I argue that ...
What is Metaphysical Equivalence? | Miller | Philosophical Papers
African Journals Online (AJOL)
Theories are metaphysically equivalent just if there is no fact of the matter that could render one theory true and the other false. In this paper I argue that if we are judiciously to resolve disputes about whether theories are equivalent or not, we need to develop testable criteria that will give us epistemic access to the obtaining ...
49 CFR 38.2 - Equivalent facilitation.
2010-10-01
... 49 Transportation 1 2010-10-01 2010-10-01 false Equivalent facilitation. 38.2 Section 38.2 Transportation Office of the Secretary of Transportation AMERICANS WITH DISABILITIES ACT (ADA) ACCESSIBILITY SPECIFICATIONS FOR TRANSPORTATION VEHICLES General § 38.2 Equivalent facilitation. Departures from particular...
Beyond Language Equivalence on Visibly Pushdown Automata
DEFF Research Database (Denmark)
Srba, Jiri
2009-01-01
We study (bi)simulation-like preorder/equivalence checking on the class of visibly pushdown automata and its natural subclasses visibly BPA (Basic Process Algebra) and visibly one-counter automata. We describe generic methods for proving complexity upper and lower bounds for a number of studied...... preorders and equivalences like simulation, completed simulation, ready simulation, 2-nested simulation preorders/equivalences and bisimulation equivalence. Our main results are that all the mentioned equivalences and preorders are EXPTIME-complete on visibly pushdown automata, PSPACE-complete on visibly...... one-counter automata and P-complete on visibly BPA. Our PSPACE lower bound for visibly one-counter automata improves also the previously known DP-hardness results for ordinary one-counter automata and one-counter nets. Finally, we study regularity checking problems for visibly pushdown automata...
Equivalence in Ventilation and Indoor Air Quality
Energy Technology Data Exchange (ETDEWEB)
Sherman, Max; Walker, Iain; Logue, Jennifer
2011-08-01
We ventilate buildings to provide acceptable indoor air quality (IAQ). Ventilation standards (such as American Society of Heating, Refrigerating, and Air-Conditioning Enginners [ASHRAE] Standard 62) specify minimum ventilation rates without taking into account the impact of those rates on IAQ. Innovative ventilation management is often a desirable element of reducing energy consumption or improving IAQ or comfort. Variable ventilation is one innovative strategy. To use variable ventilation in a way that meets standards, it is necessary to have a method for determining equivalence in terms of either ventilation or indoor air quality. This study develops methods to calculate either equivalent ventilation or equivalent IAQ. We demonstrate that equivalent ventilation can be used as the basis for dynamic ventilation control, reducing peak load and infiltration of outdoor contaminants. We also show that equivalent IAQ could allow some contaminants to exceed current standards if other contaminants are more stringently controlled.
Equilibrium Analysis in Cake Cutting
DEFF Research Database (Denmark)
Branzei, Simina; Miltersen, Peter Bro
2013-01-01
Cake cutting is a fundamental model in fair division; it represents the problem of fairly allocating a heterogeneous divisible good among agents with different preferences. The central criteria of fairness are proportionality and envy-freeness, and many of the existing protocols are designed...... to guarantee proportional or envy-free allocations, when the participating agents follow the protocol. However, typically, all agents following the protocol is not guaranteed to result in a Nash equilibrium. In this paper, we initiate the study of equilibria of classical cake cutting protocols. We consider one...... of the simplest and most elegant continuous algorithms -- the Dubins-Spanier procedure, which guarantees a proportional allocation of the cake -- and study its equilibria when the agents use simple threshold strategies. We show that given a cake cutting instance with strictly positive value density functions...
Equilibrium theory of heatless adsorption
Energy Technology Data Exchange (ETDEWEB)
Chan, Y.N.I.; Hill, F.B.; Wong, Y.W.
1979-01-01
The equilibrium theory of heatless adsorption was derived for the case of isothermal removal of a single trace adsorbable component from an inert carrier. The adsorbing component obeyed a linear distribution law. A modification is made in order to render all material balances exact. The modified theory is presented and extended to the case of the two-component system in which both components are adsorbable. A survey was made of the predictions of the corrected theory. Calculations were made of the steady state performance of a single heatless adsorption stage when operating at the condition of complete removal of the trace component from the product stream. Quantities calculated included the critical purge to feed ratio, enrichments in the purge and in the blowdown gas, and overall enrichment. Operation at the critical purge to feed ratio for perfect cleanup and the shortest column length corresponds to the condition of maximum sorbent utilization, providing an upper bound on the performance of the column. The overall enrichment increases with pressure ratio and decreases with the equilibrium parameter ..beta... It is dominated by the enrichment in the purge stream for small values of ..beta... At a purge to feed ratio greater than the critical, the overall enrichment is diminished and exhibits a maximum with respect to pressure ratio. For separation factors less than unity, only modest depletion of the trace component in th product stream is found, and this depletion is relatively insensitive to pressure ratio. From transient calculations, the number of cycles required to reach steady state increases with pressure ratio.
Neural network for solving Nash equilibrium problem in application of multiuser power control.
He, Xing; Yu, Junzhi; Huang, Tingwen; Li, Chuandong; Li, Chaojie
2014-09-01
In this paper, based on an equivalent mixed linear complementarity problem, we propose a neural network to solve multiuser power control optimization problems (MPCOP), which is modeled as the noncooperative Nash game in modern digital subscriber line (DSL). If the channel crosstalk coefficients matrix is positive semidefinite, it is shown that the proposed neural network is stable in the sense of Lyapunov and global convergence to a Nash equilibrium, and the Nash equilibrium is unique if the channel crosstalk coefficients matrix is positive definite. Finally, simulation results on two numerical examples show the effectiveness and performance of the proposed neural network. Copyright © 2014 Elsevier Ltd. All rights reserved.
Physical Equilibrium Evaluation in Parkinson Disease
Directory of Open Access Journals (Sweden)
Schmidt, Paula da Silva
2011-04-01
Full Text Available Introduction: The Parkinson disease can be among the multiple causes of alterations in the physical equilibrium. Accordingly, this study has the objective to evaluate Parkinson patients' physical equilibrium. Method: Potential study in which 12 Parkinson individuals were evaluated by way of tests of static and dynamic equilibrium, dynamic posturography and vectoelectronystagmograph. To compare the dynamic posturography results a group of gauged control was used. Results: Alterations in Romberg-Barré, Unterberger and Walk tests were found. The vestibular exam revealed 06 normal cases, 04 central vestibular syndrome and 02 cases of peripheral vestibular syndrome. In the dynamic posturography, an equilibrium alteration has been verified, when compared to the control group in all Sensorial Organization Tests, in average and in the utilization of vestibular system. Conclusion: Parkinson patients present a physical equilibrium alteration. The dynamic posturography was more sensitive to detect the equilibrium alterations than vectoelectronystagmograph.
Equilibrium Solubility of CO2 in Alkanolamines
DEFF Research Database (Denmark)
Waseem Arshad, Muhammad; Fosbøl, Philip Loldrup; von Solms, Nicolas
2014-01-01
Equilibrium solubility of CO2 were measured in aqueous solutions of Monoethanolamine (MEA) and N,N-diethylethanolamine(DEEA). Equilibrium cells are generally used for these measurements. In this study, the equilibrium data were measured from the calorimetry. For this purpose a reaction calorimeter...... (model CPA 122 from ChemiSens AB, Sweden) was used. The advantage of this method is being the measurement of both heats of absorption and equilibrium solubility data of CO2 at the same time. The measurements were performed for 30 mass % MEA and 5M DEEA solutions as a function of CO2 loading at three...... different temperatures 40, 80 and 120 ºC. The measured 30 mass % MEA and 5M DEEA data were compared with the literature data obtained from different equilibrium cells which validated the use of calorimeters for equilibrium solubility measurements....
Mathematical models and equilibrium in irreversible microeconomics
Directory of Open Access Journals (Sweden)
Anatoly M. Tsirlin
2010-07-01
Full Text Available A set of equilibrium states in a system consisting of economic agents, economic reservoirs, and firms is considered. Methods of irreversible microeconomics are used. We show that direct sale/purchase leads to an equilibrium state which depends upon the coefficients of supply/demand functions. To reach the unique equilibrium state it is necessary to add either monetary exchange or an intermediate firm.
Equilibrium sampling by reweighting nonequilibrium simulation trajectories.
Yang, Cheng; Wan, Biao; Xu, Shun; Wang, Yanting; Zhou, Xin
2016-03-01
Based on equilibrium molecular simulations, it is usually difficult to efficiently visit the whole conformational space of complex systems, which are separated into some metastable regions by high free energy barriers. Nonequilibrium simulations could enhance transitions among these metastable regions and then be applied to sample equilibrium distributions in complex systems, since the associated nonequilibrium effects can be removed by employing the Jarzynski equality (JE). Here we present such a systematical method, named reweighted nonequilibrium ensemble dynamics (RNED), to efficiently sample equilibrium conformations. The RNED is a combination of the JE and our previous reweighted ensemble dynamics (RED) method. The original JE reproduces equilibrium from lots of nonequilibrium trajectories but requires that the initial distribution of these trajectories is equilibrium. The RED reweights many equilibrium trajectories from an arbitrary initial distribution to get the equilibrium distribution, whereas the RNED has both advantages of the two methods, reproducing equilibrium from lots of nonequilibrium simulation trajectories with an arbitrary initial conformational distribution. We illustrated the application of the RNED in a toy model and in a Lennard-Jones fluid to detect its liquid-solid phase coexistence. The results indicate that the RNED sufficiently extends the application of both the original JE and the RED in equilibrium sampling of complex systems.
Studies on the Neutron Radiation Damage Equivalence
Directory of Open Access Journals (Sweden)
ZOU De-hui
2015-01-01
Full Text Available To establish a unified standard of the evaluation of different sources of radiation damage, the neutron radiation damage equivalent standard source was determined both at home and abroad, and a lot of equivalence research work was done for making weapons anti neutron radiation performance examination and acceptance basis. The theoretical research progress was combed according to the relationship between the displacement damage function and the radiation source spectra ,and the experimental research progress was combed from the basic experimental methods, the controlling trend of effect parameters and field parameters. The experiment method to reduce the uncertainty was discussed, and present the research directions of radiation damage equivalence.
Philicities, Fugalities, and Equilibrium Constants.
Mayr, Herbert; Ofial, Armin R
2016-05-17
The mechanistic model of Organic Chemistry is based on relationships between rate and equilibrium constants. Thus, strong bases are generally considered to be good nucleophiles and poor nucleofuges. Exceptions to this rule have long been known, and the ability of iodide ions to catalyze nucleophilic substitutions, because they are good nucleophiles as well as good nucleofuges, is just a prominent example for exceptions from the general rule. In a reaction series, the Leffler-Hammond parameter α = δΔG(⧧)/δΔG° describes the fraction of the change in the Gibbs energy of reaction, which is reflected in the change of the Gibbs energy of activation. It has long been considered as a measure for the position of the transition state; thus, an α value close to 0 was associated with an early transition state, while an α value close to 1 was considered to be indicative of a late transition state. Bordwell's observation in 1969 that substituent variation in phenylnitromethanes has a larger effect on the rates of deprotonation than on the corresponding equilibrium constants (nitroalkane anomaly) triggered the breakdown of this interpretation. In the past, most systematic investigations of the relationships between rates and equilibria of organic reactions have dealt with proton transfer reactions, because only for few other reaction series complementary kinetic and thermodynamic data have been available. In this Account we report on a more general investigation of the relationships between Lewis basicities, nucleophilicities, and nucleofugalities as well as between Lewis acidities, electrophilicities, and electrofugalities. Definitions of these terms are summarized, and it is suggested to replace the hybrid terms "kinetic basicity" and "kinetic acidity" by "protophilicity" and "protofugality", respectively; in this way, the terms "acidity" and "basicity" are exclusively assigned to thermodynamic properties, while "philicity" and "fugality" refer to kinetics
Distinguishing Provenance Equivalence of Earth Science Data
Tilmes, Curt; Yesha, Ye; Halem, M.
2010-01-01
Reproducibility of scientific research relies on accurate and precise citation of data and the provenance of that data. Earth science data are often the result of applying complex data transformation and analysis workflows to vast quantities of data. Provenance information of data processing is used for a variety of purposes, including understanding the process and auditing as well as reproducibility. Certain provenance information is essential for producing scientifically equivalent data. Capturing and representing that provenance information and assigning identifiers suitable for precisely distinguishing data granules and datasets is needed for accurate comparisons. This paper discusses scientific equivalence and essential provenance for scientific reproducibility. We use the example of an operational earth science data processing system to illustrate the application of the technique of cascading digital signatures or hash chains to precisely identify sets of granules and as provenance equivalence identifiers to distinguish data made in an an equivalent manner.
Nuclear Regulatory Commission equivalency evaluation report
Energy Technology Data Exchange (ETDEWEB)
Garvin, L.J.
1995-10-01
This paper provides the basis for concluding that using the seismic design criteria, defined in DOE order 4580.28, Natural Phenomena Hazards Mitigation, and its implementing standards provides safety equivalent to NRC criteria.
Equivalence Principle, Higgs Boson and Cosmology
Directory of Open Access Journals (Sweden)
Mauro Francaviglia
2013-05-01
Full Text Available We discuss here possible tests for Palatini f(R-theories together with their implications for different formulations of the Equivalence Principle. We shall show that Palatini f(R-theories obey the Weak Equivalence Principle and violate the Strong Equivalence Principle. The violations of the Strong Equivalence Principle vanish in vacuum (and purely electromagnetic solutions as well as on short time scales with respect to the age of the universe. However, we suggest that a framework based on Palatini f(R-theories is more general than standard General Relativity (GR and it sheds light on the interpretation of data and results in a way which is more model independent than standard GR itself.
REFractions: The Representing Equivalent Fractions Game
Tucker, Stephen I.
2014-01-01
Stephen Tucker presents a fractions game that addresses a range of fraction concepts including equivalence and computation. The REFractions game also improves students' fluency with representing, comparing and adding fractions.
Colin Rowe and ' Dynamic Equilibrium'
Directory of Open Access Journals (Sweden)
Pablo López Marín
2015-05-01
Full Text Available AbstractIn 1944 Gyorgy Kepes published what undoubtless will be his most influential text, "The language of vision". What Kepes tried to do was a guide of grammar and syntax of vision, which allows to face art as purely sensory experience or just visual, devisted of any literary , semantic or sentimental meaning.Among all the concepts that Kepes developes in his essay perhaps the most decisive one is the so called dynamic equilibrium, which is introduced in this work for fi rst time, verbalizing something that was in the air, orbiting around the entire modern plastic but far only explained in an empirical way.Colin Rowe reverberates the recent readed kepesian ideas on his own writings Transparency: Literal and Phenomenal and Neo-'Classicism' and Modern Architecture I and II, when the author tries to highlight the founding principles of the modern movement refusing the plastic dimension of the discipline . The article will try to expose and explain this influence.
Fractional cointegration rank estimation
DEFF Research Database (Denmark)
Lasak, Katarzyna; Velasco, Carlos
We consider cointegration rank estimation for a p-dimensional Fractional Vector Error Correction Model. We propose a new two-step procedure which allows testing for further long-run equilibrium relations with possibly different persistence levels. The fi…rst step consists in estimating the parame......We consider cointegration rank estimation for a p-dimensional Fractional Vector Error Correction Model. We propose a new two-step procedure which allows testing for further long-run equilibrium relations with possibly different persistence levels. The fi…rst step consists in estimating...... to control for stochastic trend estimation effects from the first step. The critical values of the tests proposed depend only on the number of common trends under the null, p - r, and on the interval of the cointegration degrees b allowed, but not on the true cointegration degree b0. Hence, no additional...
Dark matter and the equivalence principle
Frieman, Joshua A.; Gradwohl, Ben-Ami
1993-01-01
A survey is presented of the current understanding of dark matter invoked by astrophysical theory and cosmology. Einstein's equivalence principle asserts that local measurements cannot distinguish a system at rest in a gravitational field from one that is in uniform acceleration in empty space. Recent test-methods for the equivalence principle are presently discussed as bases for testing of dark matter scenarios involving the long-range forces between either baryonic or nonbaryonic dark matter and ordinary matter.
Non-equilibrium modelling of distillation
Wesselingh, JA; Darton, R
1997-01-01
There are nasty conceptual problems in the classical way of describing distillation columns via equilibrium stages, and efficiencies or HETP's. We can nowadays avoid these problems by simulating the behaviour of a complete column in one go using a non-equilibrium model. Such a model has phase
Approximate Equilibrium Problems and Fixed Points
Directory of Open Access Journals (Sweden)
H. Mazaheri
2013-01-01
Full Text Available We find a common element of the set of fixed points of a map and the set of solutions of an approximate equilibrium problem in a Hilbert space. Then, we show that one of the sequences weakly converges. Also we obtain some theorems about equilibrium problems and fixed points.
Equilibrium theory of island biogeography: A review
Angela D. Yu; Simon A. Lei
2001-01-01
The topography, climatic pattern, location, and origin of islands generate unique patterns of species distribution. The equilibrium theory of island biogeography creates a general framework in which the study of taxon distribution and broad island trends may be conducted. Critical components of the equilibrium theory include the species-area relationship, island-...
The Equilibrium of Life-Career Planning
Byars-Winston, Angela
Over a 100 years ago, fixed wing aircraft flight was made possible by Orville and Wilbur Wright's breakthrough invention of a three-axis control that allowed effective steering and maintenance of airplanes' equilibrium. The significance of the Wright brothers' control invention is that it facilitated recovery of lateral balance, or equilibrium, when the wind tilts the aircraft to one side or another.
equilibrium approach in thederivation of differential equations
African Journals Online (AJOL)
user
In this paper, the differential equations of Mindlin plates are derived from basic principles by simultaneous satisfaction of the differential equations of equilibrium, the stress-strain laws and the strain-displacement relations for isotropic, homogenous linear elastic materials. Equilibrium method was adopted in the derivation.
Do intertidal flats ever reach equilibrium?
Maan, D.C.; van Prooijen, B.C.; Wang, Z.B.; de Vriend, H.J.
2015-01-01
Various studies have identified a strong relation between the hydrodynamic forces and the equilibrium profile for intertidal flats. A thorough understanding of the interplay between the hydrodynamic forces and the morphology, however, concerns more than the equilibrium state alone. We study the
A Holistic Equilibrium Theory of Organization Development
Yang, Baiyin; Zheng, Wei
2005-01-01
This paper proposes a holistic equilibrium theory of organizational development (OD). The theory states that there are three driving forces in organizational change and development--rationality, reality, and liberty. OD can be viewed as a planned process of change in an organization so as to establish equilibrium among these three interacting…
Ghirardi, Marco; Marchetti, Fabio; Pettinari, Claudio; Regis, Alberto; Roletto, Ezio
2015-01-01
A didactic sequence is proposed for the teaching of chemical equilibrium law. In this approach, we have avoided the kinetic derivation and the thermodynamic justification of the equilibrium constant. The equilibrium constant expression is established empirically by a trial-and-error approach. Additionally, students learn to use the criterion of…
On the definition of equilibrium and non-equilibrium states in dynamical systems
Akimoto, Takuma
2008-01-01
We propose a definition of equilibrium and non-equilibrium states in dynamical systems on the basis of the time average. We show numerically that there exists a non-equilibrium non-stationary state in the coupled modified Bernoulli map lattice.
Equilibrium properties of quantum spin systems with nonadditive long-range interactions.
Mori, Takashi
2012-08-01
We study equilibrium states of quantum spin systems with nonadditive long-range interactions by adopting an appropriate scaling of the interaction strength, i.e., the so-called Kac prescription. In classical spin systems, it is known that the equilibrium free energy is obtained by minimizing the free-energy functional over the coarse-grained magnetization. Here we show that it is also true for quantum spin systems. From this observation, it is found that when the canonical ensemble and the microcanonical ensemble are not equivalent in some parameter region, it is not necessarily justified to replace the actual long-range interaction by the infinite-range interaction (Curie-Weiss-type interaction). On the other hand, in the parameter region where the two ensembles are equivalent, this replacement is always justified. We examine the Heisenberg XXZ model as an illustrative example and discuss the relation to experiments.
Disturbances in equilibrium function after major earthquake
Honma, Motoyasu; Endo, Nobutaka; Osada, Yoshihisa; Kim, Yoshiharu; Kuriyama, Kenichi
2012-10-01
Major earthquakes were followed by a large number of aftershocks and significant outbreaks of dizziness occurred over a large area. However it is unclear why major earthquake causes dizziness. We conducted an intergroup trial on equilibrium dysfunction and psychological states associated with equilibrium dysfunction in individuals exposed to repetitive aftershocks versus those who were rarely exposed. Greater equilibrium dysfunction was observed in the aftershock-exposed group under conditions without visual compensation. Equilibrium dysfunction in the aftershock-exposed group appears to have arisen from disturbance of the inner ear, as well as individual vulnerability to state anxiety enhanced by repetitive exposure to aftershocks. We indicate potential effects of autonomic stress on equilibrium function after major earthquake. Our findings may contribute to risk management of psychological and physical health after major earthquakes with aftershocks, and allow development of a new empirical approach to disaster care after such events.
Phase equilibrium measurements on nine binary mixtures
Energy Technology Data Exchange (ETDEWEB)
Wilding, W.V. [Brigham Young Univ., Provo, UT (United States). Chemical Engineering Dept.; Giles, N.F.; Wilson, L.C. [Wiltec Research Co. Inc., Provo, UT (United States)
1996-11-01
Phase equilibrium measurements have been performed on nine binary mixtures. The PTx method was used to obtain vapor-liquid equilibrium data for the following systems at two temperatures each: (aminoethyl)piperazine + diethylenetriamine; 2-butoxyethyl acetate + 2-butoxyethanol; 2-methyl-2-propanol + 2-methylbutane; 2-methyl-2-propanol + 2-methyl-2-butene; methacrylonitrile + methanol; 1-chloro-1,1-difluoroethane + hydrogen chloride; 2-(hexyloxy)ethanol + ethylene glycol; butane + ammonia; propionaldehyde + butane. Equilibrium vapor and liquid phase compositions were derived form the PTx data using the Soave equation of state to represent the vapor phase and the Wilson or the NRTL activity coefficient model to represent the liquid phase. A large immiscibility region exists in the butane + ammonia system at 0 C. Therefore, separate vapor-liquid-liquid equilibrium measurements were performed on this system to more precisely determine the miscibility limits and the composition of the vapor phase in equilibrium with the two liquid phases.
Information-theoretic equilibrium and observable thermalization
Anzà, F.; Vedral, V.
2017-03-01
A crucial point in statistical mechanics is the definition of the notion of thermal equilibrium, which can be given as the state that maximises the von Neumann entropy, under the validity of some constraints. Arguing that such a notion can never be experimentally probed, in this paper we propose a new notion of thermal equilibrium, focused on observables rather than on the full state of the quantum system. We characterise such notion of thermal equilibrium for an arbitrary observable via the maximisation of its Shannon entropy and we bring to light the thermal properties that it heralds. The relation with Gibbs ensembles is studied and understood. We apply such a notion of equilibrium to a closed quantum system and show that there is always a class of observables which exhibits thermal equilibrium properties and we give a recipe to explicitly construct them. Eventually, an intimate connection with the Eigenstate Thermalisation Hypothesis is brought to light.
Information-theoretic equilibrium and observable thermalization.
Anzà, F; Vedral, V
2017-03-07
A crucial point in statistical mechanics is the definition of the notion of thermal equilibrium, which can be given as the state that maximises the von Neumann entropy, under the validity of some constraints. Arguing that such a notion can never be experimentally probed, in this paper we propose a new notion of thermal equilibrium, focused on observables rather than on the full state of the quantum system. We characterise such notion of thermal equilibrium for an arbitrary observable via the maximisation of its Shannon entropy and we bring to light the thermal properties that it heralds. The relation with Gibbs ensembles is studied and understood. We apply such a notion of equilibrium to a closed quantum system and show that there is always a class of observables which exhibits thermal equilibrium properties and we give a recipe to explicitly construct them. Eventually, an intimate connection with the Eigenstate Thermalisation Hypothesis is brought to light.
Equilibrium, scale and inheritance in geomorphology
Ahnert, Frank
1994-12-01
Of the many "equilibrium" terms that have been proposed, only two are needed: dynamic equilibrium in the original sense of G.K. Gilbert (1877) and steady state. The former refers to the relationship between the process components of a system, the latter to the system as a whole. The tendency towards establishing a dynamic equilibrium is inherent in all natural systems that contain negative feedbacks between processes capable of compensating each other. In geomorphology, equilibrium tendencies of the mass budget are more relevant than those of the energy budget. The validity of the equilibrium concept is discussed at several scales from a slope point to entire slopes, drainage basins and mountain ranges. The effects of eksystemic changes vary depending upon the length of the intervals between such changes in comparison to the length of the required relaxation times. This relationship also applies to the influence of inherited forms, patterns and materials that have become components of present-day systems.
Gaussian random bridges and a geometric model for information equilibrium
Mengütürk, Levent Ali
2018-03-01
The paper introduces a class of conditioned stochastic processes that we call Gaussian random bridges (GRBs) and proves some of their properties. Due to the anticipative representation of any GRB as the sum of a random variable and a Gaussian (T , 0) -bridge, GRBs can model noisy information processes in partially observed systems. In this spirit, we propose an asset pricing model with respect to what we call information equilibrium in a market with multiple sources of information. The idea is to work on a topological manifold endowed with a metric that enables us to systematically determine an equilibrium point of a stochastic system that can be represented by multiple points on that manifold at each fixed time. In doing so, we formulate GRB-based information diversity over a Riemannian manifold and show that it is pinned to zero over the boundary determined by Dirac measures. We then define an influence factor that controls the dominance of an information source in determining the best estimate of a signal in the L2-sense. When there are two sources, this allows us to construct information equilibrium as a functional of a geodesic-valued stochastic process, which is driven by an equilibrium convergence rate representing the signal-to-noise ratio. This leads us to derive price dynamics under what can be considered as an equilibrium probability measure. We also provide a semimartingale representation of Markovian GRBs associated with Gaussian martingales and a non-anticipative representation of fractional Brownian random bridges that can incorporate degrees of information coupling in a given system via the Hurst exponent.
A general framework for ion equilibrium calculations in compacted bentonite
Birgersson, Martin
2017-03-01
An approach for treating chemical equilibrium between compacted bentonite and aqueous solutions is presented. The treatment is based on conceptualizing bentonite as a homogeneous mixture of water and montmorillonite, and assumes Gibbs-Donnan membrane equilibrium across interfaces to external solutions. An equation for calculating the electrostatic potential difference between bentonite and external solution (Donnan potential) is derived and solved analytically for some simple systems. The solutions are furthermore analyzed in order to illuminate the general mechanisms of ion equilibrium and their relation to measurable quantities. A method is suggested for estimating interlayer activity coefficients based on the notion of an interlayer ionic strength. Using this method, several applications of the framework are presented, giving a set of quantitative predictions which may be relatively simply tested experimentally, e.g.: (1) the relative amount of anions entering the bentonite depends approximately on the square-root of the external concentration for a 1:2 salt (e.g. CaCl2). For a 1:1 salt (e.g. NaCl) the dependence is approximately linear, and for a 1:2 salt (e.g. Na2SO4) the dependence is approximately quadratic. (2) Bentonite contains substantially more nitrate as compared to chloride if equilibrated with the two salt solutions at equal external concentration. (3) Potassium bentonite generally contains more anions as compared to sodium bentonite if equilibrated at the same external concentration. (4) The anion concentration ratio in two bentonite samples of different cations (but with the same density and cation exchange capacity) resembles the ion exchange selectivity coefficient for that specific cation pair. The results show that an adequate treatment of chemical equilibrium between interlayers and bulk solutions are essential when modeling compacted bentonite, and that activity corrections generally are required for relevant ion equilibrium calculations. It
Non-equilibrium dissipative supramolecular materials with a tunable lifetime
Tena-Solsona, Marta; Rieß, Benedikt; Grötsch, Raphael K.; Löhrer, Franziska C.; Wanzke, Caren; Käsdorf, Benjamin; Bausch, Andreas R.; Müller-Buschbaum, Peter; Lieleg, Oliver; Boekhoven, Job
2017-07-01
Many biological materials exist in non-equilibrium states driven by the irreversible consumption of high-energy molecules like ATP or GTP. These energy-dissipating structures are governed by kinetics and are thus endowed with unique properties including spatiotemporal control over their presence. Here we show man-made equivalents of materials driven by the consumption of high-energy molecules and explore their unique properties. A chemical reaction network converts dicarboxylates into metastable anhydrides driven by the irreversible consumption of carbodiimide fuels. The anhydrides hydrolyse rapidly to the original dicarboxylates and are designed to assemble into hydrophobic colloids, hydrogels or inks. The spatiotemporal control over the formation and degradation of materials allows for the development of colloids that release hydrophobic contents in a predictable fashion, temporary self-erasing inks and transient hydrogels. Moreover, we show that each material can be re-used for several cycles.
Multiple Depots Vehicle Routing Problem in the Context of Total Urban Traffic Equilibrium
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Dongxu Chen
2017-01-01
Full Text Available A multidepot VRP is solved in the context of total urban traffic equilibrium. Under the total traffic equilibrium, the multidepot VRP is changed to GDAP (the problem of Grouping Customers + Estimating OD Traffic + Assigning traffic and bilevel programming is used to model the problem, where the upper model determines the customers that each truck visits and adds the trucks’ trips to the initial OD (Origin/Destination trips, and the lower model assigns the OD trips to road network. Feedback between upper model and lower model is iterated through OD trips; thus total traffic equilibrium can be simulated.
KMS-like properties of local equilibrium states in quantum field theory
Gransee, Michael; Pinamonti, Nicola; Verch, Rainer
2017-07-01
A new condition, called ;Local KMS Condition;, characterizing states of a quantum field to which one can ascribe, at a given spacetime point, a temperature, is introduced in this article. It will be shown that the Local KMS Condition (LKMS condition) is equivalent to the Local Thermal Equilibrium (LTE) condition, proposed previously by Buchholz, Ojima and Roos, for states of the quantized scalar Klein-Gordon field that fulfill the analytic microlocal spectrum condition. Therefore, known examples of states fulfilling the LTE condition provide examples of states obeying the LKMS condition with a temperature distribution varying in space and time. The results extend to the generalized cases of mixed-temperature LKMS and LTE states. The LKMS condition therefore provides a promising generalization of the KMS condition, which characterizes global thermal equilibrium states with respect to an inertial time evolution, to states which are globally out of equilibrium but still possess a local temperature distribution.
Quantile equivalence to evaluate compliance with habitat management objectives
Cade, Brian S.; Johnson, Pamela R.
2011-01-01
Equivalence estimated with linear quantile regression was used to evaluate compliance with habitat management objectives at Arapaho National Wildlife Refuge based on monitoring data collected in upland (5,781 ha; n = 511 transects) and riparian and meadow (2,856 ha, n = 389 transects) habitats from 2005 to 2008. Quantiles were used because the management objectives specified proportions of the habitat area that needed to comply with vegetation criteria. The linear model was used to obtain estimates that were averaged across 4 y. The equivalence testing framework allowed us to interpret confidence intervals for estimated proportions with respect to intervals of vegetative criteria (equivalence regions) in either a liberal, benefit-of-doubt or conservative, fail-safe approach associated with minimizing alternative risks. Simple Boolean conditional arguments were used to combine the quantile equivalence results for individual vegetation components into a joint statement for the multivariable management objectives. For example, management objective 2A required at least 809 ha of upland habitat with a shrub composition ≥0.70 sagebrush (Artemisia spp.), 20–30% canopy cover of sagebrush ≥25 cm in height, ≥20% canopy cover of grasses, and ≥10% canopy cover of forbs on average over 4 y. Shrub composition and canopy cover of grass each were readily met on >3,000 ha under either conservative or liberal interpretations of sampling variability. However, there were only 809–1,214 ha (conservative to liberal) with ≥10% forb canopy cover and 405–1,098 ha with 20–30%canopy cover of sagebrush ≥25 cm in height. Only 91–180 ha of uplands simultaneously met criteria for all four components, primarily because canopy cover of sagebrush and forbs was inversely related when considered at the spatial scale (30 m) of a sample transect. We demonstrate how the quantile equivalence analyses also can help refine the numerical specification of habitat objectives and explore
DEFF Research Database (Denmark)
Christensen, Bent J.; M. Kiefer, Nicholas
1996-01-01
A thorough econometric analysis of the pure equilibrium search model is given. Minimal data requirements for estimation are unemployment durations, wages, and employment durations. An assessment of the information contribution of each data element is given. The results define the range of potenti...... application of the equilibrium search framework and form the foundation for future econometric analysis of related models....
Rupesh, Shanmughom; Muraleedharan, Chandrasekharan; Arun, Palatel
2014-01-01
This work investigates the potential of coconut shell for air-steam gasification using thermodynamic equilibrium model. A thermodynamic equilibrium model considering tar and realistic char conversion was developed using MATLAB software to predict the product gas composition. After comparing it with experimental results the prediction capability of the model is enhanced by multiplying equilibrium constants with suitable coefficients. The modified model is used to study the effect of key process parameters like temperature, steam to biomass ratio, and equivalence ratio on product gas yield, composition, and heating value of syngas along with gasification efficiency. For a steam to biomass ratio of unity, the maximum mole fraction of hydrogen in the product gas is found to be 36.14% with a lower heating value of 7.49 MJ/Nm(3) at a gasification temperature of 1500 K and equivalence ratio of 0.15.
Jotterand, Fabrice; Wangmo, Tenzin
2014-01-01
In this article we critically examine the principle of equivalence of care in prison medicine. First, we provide an overview of how the principle of equivalence is utilized in various national and international guidelines on health care provision to prisoners. Second, we outline some of the problems associated with its applications, and argue that the principle of equivalence should go beyond equivalence to access and include equivalence of outcomes. However, because of the particular context of the prison environment, third, we contend that the concept of "health" in equivalence of health outcomes needs conceptual clarity; otherwise, it fails to provide a threshold for healthy states among inmates. We accomplish this by examining common understandings of the concepts of health and disease. We conclude our article by showing why the conceptualization of diseases as clinical problems provides a helpful approach in the delivery of health care in prison.
Local Nash equilibrium in social networks.
Zhang, Yichao; Aziz-Alaoui, M A; Bertelle, Cyrille; Guan, Jihong
2014-08-29
Nash equilibrium is widely present in various social disputes. As of now, in structured static populations, such as social networks, regular, and random graphs, the discussions on Nash equilibrium are quite limited. In a relatively stable static gaming network, a rational individual has to comprehensively consider all his/her opponents' strategies before they adopt a unified strategy. In this scenario, a new strategy equilibrium emerges in the system. We define this equilibrium as a local Nash equilibrium. In this paper, we present an explicit definition of the local Nash equilibrium for the two-strategy games in structured populations. Based on the definition, we investigate the condition that a system reaches the evolutionary stable state when the individuals play the Prisoner's dilemma and snow-drift game. The local Nash equilibrium provides a way to judge whether a gaming structured population reaches the evolutionary stable state on one hand. On the other hand, it can be used to predict whether cooperators can survive in a system long before the system reaches its evolutionary stable state for the Prisoner's dilemma game. Our work therefore provides a theoretical framework for understanding the evolutionary stable state in the gaming populations with static structures.
Crosscultural measurement equivalence of the Health Assessment Questionnaire II.
Oude Voshaar, Martijn A H; Glas, Cees A W; ten Klooster, Peter M; Taal, Erik; Wolfe, Frederick; van de Laar, Mart A F J
2013-06-01
To evaluate the crosscultural measurement equivalence of the US and Dutch Health Assessment Questionnaire II (HAQ-II) in rheumatoid arthritis (RA). Item response theory (IRT) analyses were performed on US (n = 18,747) and Dutch (n = 1,022) HAQ-II data to evaluate the equivalence of crosscultural item performance. The observed inconsistencies were modeled by assigning country-specific item parameters to biased items. The impact of crosscultural item bias on the comparability of the Dutch and US total scores was analyzed by evaluating the agreement between physical function levels estimated from an IRT model with country-specific item parameters for biased items and physical function levels estimated from the original model that did not account for cultural bias. Two items showed significant crosscultural bias. However, the agreement in physical function estimates between the respecified and original models was very high, with an intraclass correlation coefficient >0.99 and Bland-Altman limits of agreement ranging from -0.08 to -0.01 on a latent scale with a mean of 0 and an SD of 1. This study suggests that the Dutch and US HAQ-II produce total scores that can be interpreted interchangeably across countries in RA studies, despite some minor bias at the item level. Copyright © 2013 by the American College of Rheumatology.
Methods for Solving Generalized Nash Equilibrium
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Biao Qu
2013-01-01
Full Text Available The generalized Nash equilibrium problem (GNEP is an extension of the standard Nash equilibrium problem (NEP, in which each player's strategy set may depend on the rival player's strategies. In this paper, we present two descent type methods. The algorithms are based on a reformulation of the generalized Nash equilibrium using Nikaido-Isoda function as unconstrained optimization. We prove that our algorithms are globally convergent and the convergence analysis is not based on conditions guaranteeing that every stationary point of the optimization problem is a solution of the GNEP.
Mixed quantum-classical equilibrium: Surface hopping.
Schmidt, J R; Parandekar, Priya V; Tully, John C
2008-07-28
We re-examine the analysis of the equilibrium limits of the fewest switches surface hopping algorithm for mixed quantum-classical dynamics. In contrast with previously reported results, we show that surface hopping does not, in general, exactly yield Boltzmann equilibrium, but that in practice the observed deviations are quite small. We also demonstrate that surface hopping does approach the exact equilibrium distribution in both the limits of small adiabatic splitting and/or strong nonadiabatic coupling. We verify these analytical results with numerical simulations for a simple two-level quantum system connected to a bath of classical particles.
Binary systems from quantum cluster equilibrium theory.
Brüssel, Marc; Perlt, Eva; Lehmann, Sebastian B C; von Domaros, Michael; Kirchner, Barbara
2011-11-21
An extension of the quantum cluster equilibrium theory to treat binary mixtures is introduced in this work. The necessary equations are derived and a possible implementation is presented. In addition an alternative sampling procedure using widely available experimental data for the quantum cluster equilibrium approach is suggested and tested. An illustrative example, namely, the binary mixture of water and dimethyl sulfoxide, is given to demonstrate the new approach. A basic cluster set is introduced containing the relevant cluster motifs. The populations computed by the quantum cluster equilibrium approach are compared to the experimental data. Furthermore, the excess Gibbs free energy is computed and compared to experiments as well.
Investigation of Non-Equilibrium Radiation for Earth Entry
Brandis, A. M.; Johnston, C. O.; Cruden, B. A.
2016-01-01
on the shock speed. The one standard deviation scatter in the EAST results was calculated to be 31%. An estimate for the upper bound of the absolute error in wall-directed heat flux was calculated. Below 9 km/s, where the relative difference is large, the absolute error in radiative heat flux due to non-equilibrium models is estimated to be less then 1 W/sq cm. At the highest shock speed of 11 km/s, the error in non-equilibrium is estimated to be less than 20 W/sq cm.
Orientifold Planar Equivalence: The Chiral Condensate
DEFF Research Database (Denmark)
Armoni, Adi; Lucini, Biagio; Patella, Agostino
2008-01-01
in SU($N$) Yang-Mills in the large $N$ limit. Then, we compute numerically those quenched condensates for $N$ up to 8. After separating the even from the odd corrections in $1/N$, we are able to show that our data support the equivalence; however, unlike other quenched observables, subleading terms......The recently introduced orientifold planar equivalence is a promising tool for solving non-perturbative problems in QCD. One of the predictions of orientifold planar equivalence is that the chiral condensates of a theory with $N_f$ flavours of Dirac fermions in the symmetric (or antisymmetric......) representation and $N_f$ flavours of Majorana fermions in the adjoint representation have the same large $N$ value for any value of the mass of the (degenerate) fermions. Assuming the invariance of the theory under charge conjugation, we prove this statement on the lattice for staggered quenched condensates...
Weak Equivalence Principle Test on a Sounding Rocket
Phillips, James D; Popescu, Eugeniu M; Rocco, Emanuele; Thapa, Rajesh; Reasenberg, Robert D; Lorenzini, Enrico C
2010-01-01
SR-POEM, our principle of equivalence measurement on a sounding rocket, will compare the free fall rate of two substances yielding an uncertainty of E-16 in the estimate of \\eta. During the past two years, the design concept has matured and we have been working on the required technology, including a laser gauge that is self aligning and able to reach 0.1 pm per root hertz for periods up to 40 s. We describe the status and plans for this project.
Dynamic determination of equivalent CT source models for personalized dosimetry
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Rosendahl Stephan
2017-09-01
Full Text Available With improvements in CT technology, the need for reliable patient-specific dosimetry increased in the recent years. The accuracy of Monte-Carlo simulations for absolute dose estimation is related to scanner specific information on the X-ray spectra of the scanner as well as the form filter geometries and compositions. In this work a mobile measurement setup is developed, which allows both to determine the X-ray spectra and equivalent form filter of a specific scanner from just one helical scan in less than 2 minutes.
Equivalence Problem Solvability in Biparametric Gateway Program Models
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A. E. Molchanov
2014-01-01
Full Text Available Algebraic program models with procedures are designed to analyze program semantic properties on their models called program schemes. Procedural liberisation problem and equivalence problem are stated for program models with procedures in which both defining parameters are chosen independently. Program models with procedures built over a given program model without procedures are investigated. Algorithms for both stated tasks are proposed for models where an additional restriction is applied: the intersection emptiness problem is solvable in the program model without procedures. Polynomial estimates for the complexity of the algorithms are shown. Some topics for further investigation are proposed.
The equivalent incidence angle for porous absorbers backed by a hard surface
DEFF Research Database (Denmark)
Jeong, Cheol-Ho; Brunskog, Jonas
2013-01-01
An equivalent incidence angle is defined as the incidence angle at which the oblique incidence absorption coefficient best approximates the random incidence absorption coefficient. Once the equivalent angle is known, the random incidence absorption coefficient can be estimated by a single...... experiment using a free-field absorption measurement technique with a source at the equivalent angle. This study investigates the equivalent angle for locally and extendedly reacting porous media mainly by a numerical approach: Numerical minimizations of a cost function that is the difference between...... the oblique incidence absorption coefficient at a specific incidence angle and the random incidence absorption coefficient. The equivalent angle is found to be around 55 under local reaction conditions, and 45 for extendedly reacting porous absorbers. As practical guidelines for measuring absorption...
Equivalent circuit analysis of terahertz metamaterial filters
Zhang, Xueqian
2011-01-01
An equivalent circuit model for the analysis and design of terahertz (THz) metamaterial filters is presented. The proposed model, derived based on LMC equivalent circuits, takes into account the detailed geometrical parameters and the presence of a dielectric substrate with the existing analytic expressions for self-inductance, mutual inductance, and capacitance. The model is in good agreement with the experimental measurements and full-wave simulations. Exploiting the circuit model has made it possible to predict accurately the resonance frequency of the proposed structures and thus, quick and accurate process of designing THz device from artificial metamaterials is offered. ©2011 Chinese Optics Letters.
Fiscal adjustments in Europe and Ricardian equivalence
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V. DE BONIS
1998-09-01
Full Text Available According to the ‘Ricardian’ equivalence hypothesis, consumption is dependent on permanent disposable income and current deficits are equivalent to future tax payments. This hypothesis is tested on 14 European countries in the 1990s. The relationships between private sector savings and general government deficit, and the GDP growth rate and the unemployment rate are determined. The results show the change in consumers' behaviour with respect to government deficit, and that expectations of an increase in future wealth are no longer associated with a decrease in deficit.
TRANSLATION EQUIVALENCE AND CONTEXT CONSIDERATION IN GOOGLE
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I Made Sena Darmasetiyawan
2014-05-01
Full Text Available This article aims at describing the translation methods of this tool through equivalence and context consideration which also suggest the account of language database within. The data was taken from Google Translate because it is one of the most reliable tools of translation through internet service. Results showed that there are three basic reference methods of frequency, graphology, and contextual matching database in the translation. Context in discourse and equivalence in translation are used in order to analyze the extent of this consideration.
A Logical Characterisation of Static Equivalence
DEFF Research Database (Denmark)
Hüttel, Hans; Pedersen, Michael D.
2007-01-01
The work of Abadi and Fournet introduces the notion of a frame to describe the knowledge of the environment of a cryptographic protocol. Frames are lists of terms; two frames are indistinguishable under the notion of static equivalence if they satisfy the same equations on terms. We present a first......-order logic for frames with quantification over environment knowledge which, under certain general conditions, characterizes static equivalence and is amenable to construction of characteristic formulae. The logic can be used to reason about environment knowledge and can be adapted to a particular application...
Modeling Stochastic Route Choice Behaviors with Equivalent Impedance
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Jun Li
2015-01-01
Full Text Available A Logit-based route choice model is proposed to address the overlapping and scaling problems in the traditional multinomial Logit model. The nonoverlapping links are defined as a subnetwork, and its equivalent impedance is explicitly calculated in order to simply network analyzing. The overlapping links are repeatedly merged into subnetworks with Logit-based equivalent travel costs. The choice set at each intersection comprises only the virtual equivalent route without overlapping. In order to capture heterogeneity in perception errors of different sizes of networks, different scale parameters are assigned to subnetworks and they are linked to the topological relationships to avoid estimation burden. The proposed model provides an alternative method to model the stochastic route choice behaviors without the overlapping and scaling problems, and it still maintains the simple and closed-form expression from the MNL model. A link-based loading algorithm based on Dial’s algorithm is proposed to obviate route enumeration and it is suitable to be applied on large-scale networks. Finally a comparison between the proposed model and other route choice models is given by numerical examples.
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Que Yun
2016-05-01
Full Text Available In order to reveal the fluctuation effect of equilibrium moisture content of low subgrade in hot and humid climatic regions, the effect of temperature on the fluctuation of the equilibrium moisture content of subgrade was analysed. Taking the typical climate and the subgrade soil in Fujian province as an example, three technological methods - theoretical analysis, numerical simulation and indoor simulation experiment - were adopted in the investigation of the fluctuation effect of equilibrium moisture content of subgrade. The results show that, computing results from the formula of the equilibrium moisture content of subgrade, the numerical simulation results are closer to each other in consideration of the temperature effect. The test results can not reflect the relationship between the equilibrium moisture content and the height of embankment. The maximum fluctuation range of the equilibrium moisture content of the cement concrete pavement is less than 2 percent in Fujian area, and this phenomenon presents the effect of the moist-hot climate on the equilibrium moisture content. Equilibrium moisture content presents a declining trend with the increment of the temperature and the compactness. So, if matric potential considering temperature indirectly reflects the influence of thermal potential, then the equilibrium moisture content of low subgrade under high groundwater level can be estimated approximately. The fluctuation range of equilibrium moisture content in different layers of subgrade can be reduced effectively with the increment of the roadbed compaction degree.
Quantum mechanical evolution towards thermal equilibrium.
Linden, Noah; Popescu, Sandu; Short, Anthony J; Winter, Andreas
2009-06-01
The circumstances under which a system reaches thermal equilibrium, and how to derive this from basic dynamical laws, has been a major question from the very beginning of thermodynamics and statistical mechanics. Despite considerable progress, it remains an open problem. Motivated by this issue, we address the more general question of equilibration. We prove, with virtually full generality, that reaching equilibrium is a universal property of quantum systems: almost any subsystem in interaction with a large enough bath will reach an equilibrium state and remain close to it for almost all times. We also prove several general results about other aspects of thermalization besides equilibration, for example, that the equilibrium state does not depend on the detailed microstate of the bath.
Equilibrium Molecular Interactions in Pure Gases
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Boris I. Sedunov
2012-01-01
Full Text Available The equilibrium molecular interactions in pure real gases are investigated based on the chemical thermodynamics principles. The parallels between clusters in real gases and chemical compounds in equilibrium media have been used to improve understanding of the real gas structure. A new approach to the equilibrium constants for the cluster fractions and new methods to compute them and their significant parameters from the experimental thermophysical data are developed. These methods have been applied to some real gases, such as Argon and Water vapors and gaseous Alkanes. It is shown that the four-particle clusters make a noticeable contribution in the thermophysical properties of the equilibrium Water vapor. It is shown also that the effective bond energy for dimers in Alkanes linearly grows with the number of carbon atoms in the molecule.
Equilibrium Reconstruction on the Large Helical Device
Energy Technology Data Exchange (ETDEWEB)
Samuel A. Lazerson, D. Gates, D. Monticello, H. Neilson, N. Pomphrey, A. Reiman S. Sakakibara, and Y. Suzuki
2012-07-27
Equilibrium reconstruction is commonly applied to axisymmetric toroidal devices. Recent advances in computational power and equilibrium codes have allowed for reconstructions of three-dimensional fields in stellarators and heliotrons. We present the first reconstructions of finite beta discharges in the Large Helical Device (LHD). The plasma boundary and magnetic axis are constrained by the pressure profile from Thomson scattering. This results in a calculation of plasma beta without a-priori assumptions of the equipartition of energy between species. Saddle loop arrays place additional constraints on the equilibrium. These reconstruction utilize STELLOPT, which calls VMEC. The VMEC equilibrium code assumes good nested flux surfaces. Reconstructed magnetic fields are fed into the PIES code which relaxes this constraint allowing for the examination of the effect of islands and stochastic regions on the magnetic measurements.
Computation of Phase Equilibrium and Phase Envelopes
DEFF Research Database (Denmark)
Ritschel, Tobias Kasper Skovborg; Jørgensen, John Bagterp
and 2) nonideal gases and liquids modeled with cubic equations of state. Next, we derive the equilibrium conditions for an isothermal-isobaric (constant temperature, constant pressure) vapor-liquid equilibrium process (PT flash), and we present a method for the computation of phase envelopes. We......In this technical report, we describe the computation of phase equilibrium and phase envelopes based on expressions for the fugacity coefficients. We derive those expressions from the residual Gibbs energy. We consider 1) ideal gases and liquids modeled with correlations from the DIPPR database...... formulate the involved equations in terms of the fugacity coefficients. We present expressions for the first-order derivatives. Such derivatives are necessary in computationally efficient gradient-based methods for solving the vapor-liquid equilibrium equations and for computing phase envelopes. Finally, we...
Referesher Course on Contemporary Non-Equilibrium ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 7. Referesher Course on Contemporary Non-Equilibrium Thermodynamics and Statistical Mechanics. Information and Announcements Volume 15 Issue 7 July 2010 pp 678-678 ...
Quantum mechanical evolution towards thermal equilibrium
Linden, Noah; Popescu, Sandu; Short, Anthony J.; Winter, Andreas
2008-01-01
The circumstances under which a system reaches thermal equilibrium, and how to derive this from basic dynamical laws, has been a major question from the very beginning of thermodynamics and statistical mechanics. Despite considerable progress, it remains an open problem. Motivated by this issue, we address the more general question of equilibration. We prove, with virtually full generality, that reaching equilibrium is a universal property of quantum systems: Almost any subsystem in interacti...
Non-equilibrium quantum heat machines
Alicki, Robert; Gelbwaser, David
2015-01-01
Standard heat machines (engine, heat pump, refrigerator) are composed of a system ("working fluid") coupled to at least two equilibrium baths at different temperatures and periodically driven by an external device (piston or rotor) called sometimes work reservoir. The aim of this paper is to go beyond this scheme by considering environments which are stationary but cannot be decomposed into few baths at thermal equilibrium. Such situations are important, for example in solar cells, chemical m...
The Cournot Equilibrium for n Firms
Directory of Open Access Journals (Sweden)
Gina Ioan
2015-05-01
Full Text Available Oligopoly is a market situation where there are a small number of bidders (at least two of a good non-substituent and a sufficient number of consumers. The paper analyses the Cournot equilibrium in both cases where each firm assumes the role of leadership and after when firms act simultaneously on market. There are obtained the equilibrium productions, maximum profits and sales price.
Equilibrium gels of limited valence colloids
Sciortino, Francesco; Zaccarelli, Emanuela
2017-01-01
Gels are low-packing arrested states of matter which are able to support stress. On cooling, limited valence colloidal particles form open networks stabilized by the progressive increase of the interparticle bond lifetime. These gels, named equilibrium gels, are the focus of this review article. Differently from other types of colloidal gels, equilibrium gels do not require an underlying phase separation to form. Oppositely, they form in a region of densities deprived of thermodynamic instabi...
Thermodynamics and fluctuations far from equilibrium
Ross, John
2008-01-01
This book deals with the formulation of the thermodynamics of chemical and other systems far from equilibrium, including connections to fluctuations. It contains applications to non-equilibrium stationary states and approaches to such states, systems with multiple stationary states, stability and equi-stability conditions, reaction diffusion systems, transport properties, and electrochemical systems. The theoretical treatment is complemented by experimental results to substantiate the formulation. Dissipation and efficiency are analyzed in autonomous and externally forced reactions, including several biochemical systems.
Internal equilibrium layer growth over forest
DEFF Research Database (Denmark)
Dellwik, E.; Jensen, N.O.
2000-01-01
the magnitude of the scatter. Different theoretical friction velocity profiles for the Internal Boundary Layer (IBL) are tested against the forest data. The results yield information on the Internal Equilibrium Layer (IEL) growth and an equation for the IEL height fur neutral conditions is derived. For stable...... conditions the results indicate that very long fetches are required in order to measure parameters in equilibrium with the actual surface....
Non-equilibrium dog-flea model
Ackerson, Bruce J.
2017-11-01
We develop the open dog-flea model to serve as a check of proposed non-equilibrium theories of statistical mechanics. The model is developed in detail. Then it is applied to four recent models for non-equilibrium statistical mechanics. Comparison of the dog-flea solution with these different models allows checking claims and giving a concrete example of the theoretical models.
Hart, Sheryl
2015-01-01
For decades, the state of Arizona has used the General Educational Development (GED) Test to award the Arizona High School Equivalency (HSE) Diploma, as the GED Test was the only test available, recognized and accepted in the United States as the measure by which adults could demonstrate the educational attainment equivalent to high school…
An analytical model of crater count equilibrium
Hirabayashi, Masatoshi; Minton, David A.; Fassett, Caleb I.
2017-06-01
Crater count equilibrium occurs when new craters form at the same rate that old craters are erased, such that the total number of observable impacts remains constant. Despite substantial efforts to understand this process, there remain many unsolved problems. Here, we propose an analytical model that describes how a heavily cratered surface reaches a state of crater count equilibrium. The proposed model formulates three physical processes contributing to crater count equilibrium: cookie-cutting (simple, geometric overlap), ejecta-blanketing, and sandblasting (diffusive erosion). These three processes are modeled using a degradation parameter that describes the efficiency for a new crater to erase old craters. The flexibility of our newly developed model allows us to represent the processes that underlie crater count equilibrium problems. The results show that when the slope of the production function is steeper than that of the equilibrium state, the power law of the equilibrium slope is independent of that of the production function slope. We apply our model to the cratering conditions in the Sinus Medii region and at the Apollo 15 landing site on the Moon and demonstrate that a consistent degradation parameterization can successfully be determined based on the empirical results of these regions. Further developments of this model will enable us to better understand the surface evolution of airless bodies due to impact bombardment.
Inference of directional selection and mutation parameters assuming equilibrium.
Vogl, Claus; Bergman, Juraj
2015-12-01
In a classical study, Wright (1931) proposed a model for the evolution of a biallelic locus under the influence of mutation, directional selection and drift. He derived the equilibrium distribution of the allelic proportion conditional on the scaled mutation rate, the mutation bias and the scaled strength of directional selection. The equilibrium distribution can be used for inference of these parameters with genome-wide datasets of "site frequency spectra" (SFS). Assuming that the scaled mutation rate is low, Wright's model can be approximated by a boundary-mutation model, where mutations are introduced into the population exclusively from sites fixed for the preferred or unpreferred allelic states. With the boundary-mutation model, inference can be partitioned: (i) the shape of the SFS distribution within the polymorphic region is determined by random drift and directional selection, but not by the mutation parameters, such that inference of the selection parameter relies exclusively on the polymorphic sites in the SFS; (ii) the mutation parameters can be inferred from the amount of polymorphic and monomorphic preferred and unpreferred alleles, conditional on the selection parameter. Herein, we derive maximum likelihood estimators for the mutation and selection parameters in equilibrium and apply the method to simulated SFS data as well as empirical data from a Madagascar population of Drosophila simulans. Copyright © 2015 Elsevier Inc. All rights reserved.
NON-EQUILIBRIUM ELECTRONS IN THE OUTSKIRTS OF GALAXY CLUSTERS
Energy Technology Data Exchange (ETDEWEB)
Avestruz, Camille; Nagai, Daisuke; Lau, Erwin T. [Department of Physics, Yale University, New Haven, CT 06520 (United States); Nelson, Kaylea, E-mail: camille.avestruz@yale.edu, E-mail: camille.avestruz@yale.edu [Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT 06520 (United States)
2015-08-01
The analysis of X-ray and Sunyaev–Zel’dovich measurements of the intracluster medium (ICM) assumes that electrons are in thermal equilibrium with ions in the plasma. However, in the outskirts of galaxy clusters, the electron–ion equilibration timescale can become comparable to the Hubble time, leading to systematic biases in cluster mass estimates and mass-observable scaling relations. To quantify an upper limit of the impact of non-equilibrium electrons, we use a mass-limited sample of simulated galaxy clusters taken from a cosmological simulation with a two-temperature model that assumes the Spitzer equilibration time for the electrons and ions. We show that the temperature bias is more pronounced in more massive and rapidly accreting clusters. For the most extreme case, we find that the bias is of the order of 10% at half of the cluster virial radius and increases to 40% at the edge of the cluster. Gas in filaments is less susceptible to the non-equilibrium effect, leading to azimuthal variations in the temperature bias at large cluster-centric radii. Using mock Chandra observations of simulated clusters, we show that the bias manifests in ultra-deep X-ray observations of cluster outskirts and quantify the resulting biases in hydrostatic mass and cluster temperature derived from these observations. We provide a mass-dependent fitting function for the temperature bias profile, which can be useful for modeling the effect of electron-ion equilibration in galaxy clusters.
Fuel Cell Equivalent Electric Circuit Parameter Mapping
DEFF Research Database (Denmark)
Jeppesen, Christian; Zhou, Fan; Andreasen, Søren Juhl
In this work a simple model for a fuel cell is investigated for diagnostic purpose. The fuel cell is characterized, with respect to the electrical impedance of the fuel cell at non-faulty conditions and under variations in load current. Based on this the equivalent electrical circuit parameters can...
Identifiability and Equivalence of GLLIRM Models
Revuelta, Javier
2009-01-01
The generalized logit-linear item response model (GLLIRM) is a linearly constrained nominal categories model (NCM) that computes the scale and intercept parameters for categories as a weighted sum of basic parameters. This paper addresses the problems of the identifiability of the basic parameters and the equivalence between different GLLIRM…
Confluence Modulo Equivalence in Constraint Handling Rules
DEFF Research Database (Denmark)
Christiansen, Henning; Kirkeby, Maja Hanne
2014-01-01
Previous results on confluence for Constraint Handling Rules, CHR, are generalized to take into account user-defined state equivalence relations. This allows a much larger class of programs to enjoy the ad- vantages of confluence, which include various optimization techniques and simplified corre...
interpratation: of equivalences and cultural untranslatability
African Journals Online (AJOL)
jgmweri
interpretation?; How does lack of equivalences affect interpretation? Key words: Sign Language, Interpretation, Translation, linguistics, context ... World Federation of the Deaf (WFD's) vision 2020 in which it envisions that by the year ... sign 1b) can mean MANY or A LOT: 1c) can have three meaning i.e. FOR EXAMPLE,.
An Equivalent Circuit for Landau Damping
DEFF Research Database (Denmark)
Pécseli, Hans
1976-01-01
An equivalent circuit simulating the effect of Landau damping in a stable plasma‐loaded parallel‐plate capacitor is presented. The circuit contains a double infinity of LC components. The transition from stable to unstable plasmas is simulated by the introduction of active elements into the circuit....
On Behavioral Equivalence of Rational Representations
Trentelman, Harry L.; Willems, JC; Hara, S; Ohta, Y; Fujioka, H
2010-01-01
This article deals with the equivalence of representations of behaviors of linear differential systems In general. the behavior of a given linear differential system has many different representations. In this paper we restrict ourselves to kernel representations and image representations Two kernel
Equivalence domination in graphs | Arumugam | Quaestiones ...
African Journals Online (AJOL)
Click on the link to view the abstract. Keywords: Equivalence domination, total domination, P3-forming set. Quaestiones Mathematicae 36(2013), 331-340. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.2989/16073606.2013.779959 · AJOL African ...
A Criticism of Healthy-years Equivalents
P.P. Wakker (Peter)
1996-01-01
textabstractThe following questions describe the scope of this paper. When decision trees are used to analyze optimal decisions, should end nodes be evaluated on the basis of QALYs or on the basis of healthy-years equivalents? Which measures should be used in communications with others, e.g.,
A criticism of healthy-years equivalents
Wakker, P.P.
1996-01-01
The following questions describe the scope of this paper. When decision trees are used to analyze optimal decisions, should end nodes be evaluated on the basis of QALYs or on the basis of healthy-years equivalents? Which measures should be used in communication with others, e.g., patients? Which of
Conservation Laws, Equivalence Principle and Forbidden Radiation ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 17; Issue 3. Conservation Laws, Equivalence Principle and Forbidden Radiation Modes. Cihan Saçlioğlu. General ... Author Affiliations. Cihan Saçlioğlu1. Faculty of Engineering and Natural Sciences, Sabanci University, 81474 Tuzla, Istanbul, Turkey.
Conservation Laws, Equivalence Principle and Forbidden Radiation ...
Indian Academy of Sciences (India)
There are standard proofs showing there can be no monopole electromagnetic radiation and no dipole gravitational radiation. We supplement these with a global topological argument for the former, and a local argument based directly on the principle of equivalence for the latter. 1. Introduction: Wave and Particle Pictures ...
Bilingual Dictionaries and Communicative Equivalence for a ...
African Journals Online (AJOL)
Speakers in a multilingual society often employ a bilingual dictionary as the only instrument to meet their lexicographic needs. This implies that a bilingual dictionary becomes a poly functional instrument, presenting more information than just translation equivalents. This article focuses on the contents and the presentation ...
Stimulus Equivalence in Rudimentary Reading and Spelling.
Mackay, Harry A.
1985-01-01
Programs were designed to teach three severely retarded adolescents to use individual anagram letters to construct the appropriate color words when shown color patches. After learning visual equivalences between colors and printed words, Ss demonstrated auditory reading-comprehension (matching printed words to dictated words) and oral reading…
21 CFR 26.39 - Equivalence assessment.
2010-04-01
... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Equivalence assessment. 26.39 Section 26.39 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL MUTUAL RECOGNITION OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL DEVICE QUALITY SYSTEM AUDIT REPORTS, AND CERTAIN MEDICAL DEVICE PRODUCT...
CP Violation, Neutral Currents, and Weak Equivalence
Fitch, V. L.
1972-03-23
Within the past few months two excellent summaries of the state of our knowledge of the weak interactions have been presented. Correspondingly, we will not attempt a comprehensive review but instead concentrate this discussion on the status of CP violation, the question of the neutral currents, and the weak equivalence principle.
Confluence Modulo Equivalence in Constraint Handling Rules
DEFF Research Database (Denmark)
Christiansen, Henning; Kirkeby, Maja Hanne
2015-01-01
Previous results on confluence for Constraint Handling Rules, CHR, are generalized to take into account user-defined state equivalence relations. This allows a much larger class of programs to enjoy the advantages of confluence, which include various optimization techniques and simplified...
interpratation: of equivalences and cultural untranslatability
African Journals Online (AJOL)
jgmweri
communicative situation – this involves not only linguistic and cultural competence but ... Diversity in language use – how does it affect interpretation? ; Does direct and indirect use of language, social customs and relationships, how people express emotions have any ..... 1.3.3 Grammatical- Syntactical Equivalences.
Chemical equivalence assessment of three brands of ...
African Journals Online (AJOL)
Assay for content of active ingredients is a critical test of drug quality; failure to meet up the standard for content of active ingredients will result to sub therapeutic quantities. Three brands (A, B and C) of carbamazepine were assayed to determine their chemical equivalence as well as their anticonvulsant activities. This was ...
Four equivalent lot-sizing models
W. van den Heuvel (Wilco); A.P.M. Wagelmans (Albert)
2007-01-01
textabstractWe study the following lot-sizing models that recently appeared in the literature: a lot-sizing model with a remanufacturing option, a lot-sizing model with production time windows, and a lot-sizing model with cumulative capacities. We show the equivalence of these models with a
Contextual dependencies in a stimulus equivalence paradigm
Dibbets, P.; Maes, J.H.R.; Vossen, J.M.H.
2002-01-01
Two experiments with human subjects assessed contextual dependencies in a stimulus equivalence paradigm. Subjects learned to form two sets of stimuli in a matching-to-sample training procedure. Each set was presented against one of two different background colours, the contextual cues. At test, the
Directory of Open Access Journals (Sweden)
Lourival Marin Mendes
2014-03-01
Full Text Available The aim of this study was to evaluate different statistical models to estimate the equilibrium moisture content of OSB panels exposed to different conditions of air temperature and relative humidity, And also to evaluate the influence of the adhesive and veneer inclusion in the equilibrium moisture content. The panels were produced with three different adhesive types (phenol-formaldehyde - FF, melamine-urea-formaldehyde - MUF, and phenol-melamine-urea-formaldehyde - PMUF and with and without veneer inclusion. The evaluation of the equilibrium moisture content of the panels was carried out at temperatures of 30, 40 and 50°C and relative humidity of 40, 50, 60, 70, 80 and 90%. The modeling of equilibrium moisture content was performed using the statistical non-linear and polynomial models. In general, the polynomial models are most indicated for determining the equilibrium moisture content of OSB. The models adjusted only with air relative humidity presented the best precision measurements. The type of adhesive affected the equilibrium moisture content of the panels, being observed for adhesives PMUF and FF the same trend of variation, and the highest values obtained for the panels produced with adhesive MUF. The veneer inclusion decreased the equilibrium moisture content only in the panels with MUF adhesive.
Khanh, Phan Quoc; Plubtieng, Somyot; Sombut, Kamonrat
2014-01-01
The purpose of this paper is introduce several types of Levitin-Polyak well-posedness for bilevel vector equilibrium and optimization problems with equilibrium constraints. Base on criterion and characterizations for these types of Levitin-Polyak well-posedness we argue on diameters and Kuratowski’s, Hausdorff’s, or Istrǎtescus measures of noncompactness of approximate solution sets under suitable conditions, and we prove the Levitin-Polyak well-posedness for bilevel vector equilibrium and op...
Directory of Open Access Journals (Sweden)
Enrico Sciubba
2017-11-01
Full Text Available The paper discusses how the two thermodynamic properties, energy (U and exergy (E, can be used to solve the problem of quantifying the entropy of non-equilibrium systems. Both energy and exergy are a priori concepts, and their formal dependence on thermodynamic state variables at equilibrium is known. Exploiting the results of a previous study, we first calculate the non-equilibrium exergy En-eq can be calculated for an arbitrary temperature distributions across a macroscopic body with an accuracy that depends only on the available information about the initial distribution: the analytical results confirm that En-eq exponentially relaxes to its equilibrium value. Using the Gyftopoulos-Beretta formalism, a non-equilibrium entropy Sn-eq(x,t is then derived from En-eq(x,t and U(x,t. It is finally shown that the non-equilibrium entropy generation between two states is always larger than its equilibrium (herein referred to as “classical” counterpart. We conclude that every iso-energetic non-equilibrium state corresponds to an infinite set of non-equivalent states that can be ranked in terms of increasing entropy. Therefore, each point of the Gibbs plane corresponds therefore to a set of possible initial distributions: the non-equilibrium entropy is a multi-valued function that depends on the initial mass and energy distribution within the body. Though the concept cannot be directly extended to microscopic systems, it is argued that the present formulation is compatible with a possible reinterpretation of the existing non-equilibrium formulations, namely those of Tsallis and Grmela, and answers at least in part one of the objections set forth by Lieb and Yngvason. A systematic application of this paradigm is very convenient from a theoretical point of view and may be beneficial for meaningful future applications in the fields of nano-engineering and biological sciences.
Energy Technology Data Exchange (ETDEWEB)
McCoskey, Jacob K. [Washington River Protection Solutions LLC, Richland, WA (United States); Cooke, Gary A. [Washington River Protection Solutions LLC, Richland, WA (United States); Herting, Daniel L. [Washington River Protection Solutions LLC, Richland, WA (United States)
2015-09-23
The purposes of the study described in this document follow; Determine or estimate the thermodynamic equilibrium of gibbsite in contact with two real tank waste supernatant liquids through both dissolution of gibbsite (bottom-up approach) and precipitation of aluminum-bearing solids (top-down approach); determine or estimate the thermodynamic equilibrium of a mixture of gibbsite and real tank waste saltcake in contact with real tank waste supernatant liquid through both dissolution of gibbsite and precipitation of aluminum-bearing solids; and characterize the solids present after equilibrium and precipitation of aluminum-bearing solids.
Equivalent Mass versus Life Cycle Cost for Life Support Technology Selection
Jones, Harry
2003-01-01
The decision to develop a particular life support technology or to select it for flight usually depends on the cost to develop and fly it. Other criteria such as performance, safety, reliability, crew time, and technical and schedule risk are considered, but cost is always an important factor. Because launch cost would account for much of the cost of a future planetary mission, and because launch cost is directly proportional to the mass launched, equivalent mass has been used instead of cost to select advanced life support technology. The equivalent mass of a life support system includes the estimated mass of the hardware and of the spacecraft pressurized volume, power supply, and cooling system that the hardware requires. The equivalent mass of a system is defined as the total payload launch mass needed to provide and support the system. An extension of equivalent mass, Equivalent System Mass (ESM), has been established for use in the Advanced Life Support project. ESM adds a mass-equivalent of crew time and possibly other cost factors to equivalent mass. Traditional equivalent mass is strictly based on flown mass and reflects only the launch cost. ESM includes other important cost factors, but it complicates the simple flown mass definition of equivalent mass by adding a non-physical mass penalty for crew time that may exceed the actual flown mass. Equivalent mass is used only in life support analysis. Life Cycle Cost (LCC) is much more commonly used. LCC includes DDT&E, launch, and operations costs. For Earth orbit rather than planetary missions, the launch cost is less than the cost of Design, Development, Test, and Evaluation (DDTBE). LCC is a more inclusive cost estimator than equivalent mass. The relative costs of development, launch, and operations vary depending on the mission destination and duration. Since DDTBE or operations may cost more than launch, LCC gives a more accurate relative cost ranking than equivalent mass. To select the lowest cost
Equivalent configurations of optical transformation media.
Chen, Tungyang; Cheng, Shen-Wen; Weng, Chung-Ning
2009-11-09
We demonstrate that a medium consisting of two adjoining distinct layers of transformation materials, corresponding respectively to two linear coordinate transformations, can behave effectively as that of the same region transformed by another linear transformation. The equivalence means that, irrespective of the direction of incident wave, the fields of the medium exterior to the transformed regions of the two configurations are exactly the same. This property can also apply to a domain that is transformed by a piecewise linear transformation function, and to a medium that is mapped by a general curved function. This proof is shown analytically based on a rigorous Fourier-Bessel analysis. The equivalence suggests that, for a given transformed domain, one can find an infinite number of complementary media that altogether can give a desired effective response of certain transformation path.
Orientifold Planar Equivalence: The Quenched Meson Spectrum
Lucini, Biagio; Patella, Agostino; Rago, Antonio
2010-01-01
A numerical study of Orientifold Planar Equivalence is performed in SU(N) Yang-Mills theories for N=2,3,4,6. Quenched meson masses are extracted in the antisymmetric, symmetric and adjoint representations for the pseudoscalar and vector channels. An extrapolation of the vector mass as a function of the pseudoscalar mass to the large-N limit shows that the numerical results agree within errors for the three theories, as predicted by Orientifold Planar Equivalence. As a byproduct of the extrapolation, the size of the corrections up to O(1/N^3) are evaluated. A crucial prerequisite for the extrapolation is the determination of an analytical relationship between the corrections in the symmetric and in the antisymmetric representations, order by order in a 1/N expansion.
Thevenin Equivalent Method for Dynamic Contingency Assessment
DEFF Research Database (Denmark)
Møller, Jakob Glarbo; Jóhannsson, Hjörtur; Østergaard, Jacob
2015-01-01
A method that exploits Thevenin equivalent representation for obtaining post-contingency steady-state nodal voltages is integrated with a method of detecting post-contingency aperiodic small-signal instability. The task of integrating stability assessment with contingency assessment is challenged...... by the cases of unstable post-contingency conditions. For unstable postcontingency conditions there exists no credible steady-state which can be used for basis of a stability assessment. This paper demonstrates how Thevenin Equivalent methods can be applied in algebraic representation of such bifurcation...... points which may be used in assessment of post-contingency aperiodic small-signal stability. The assessment method is introduced with a numeric example....
On equivalent resistance of electrical circuits
Kagan, Mikhail
2015-01-01
While the standard (introductory physics) way of computing the equivalent resistance of nontrivial electrical circuits is based on Kirchhoff's rules, there is a mathematically and conceptually simpler approach, called the method of nodal potentials, whose basic variables are the values of the electric potential at the circuit's nodes. In this paper, we review the method of nodal potentials and illustrate it using the Wheatstone bridge as an example. We then derive a closed-form expression for the equivalent resistance of a generic circuit, which we apply to a few sample circuits. The result unveils a curious interplay between electrical circuits, matrix algebra, and graph theory and its applications to computer science. The paper is written at a level accessible by undergraduate students who are familiar with matrix arithmetic. Additional proofs and technical details are provided in appendices.
Testing the Equivalence of Regular Languages
Directory of Open Access Journals (Sweden)
Marco Almeida
2009-07-01
Full Text Available The minimal deterministic finite automaton is generally used to determine regular languages equality. Antimirov and Mosses proposed a rewrite system for deciding regular expressions equivalence of which Almeida et al. presented an improved variant. Hopcroft and Karp proposed an almost linear algorithm for testing the equivalence of two deterministic finite automata that avoids minimisation. In this paper we improve the best-case running time, present an extension of this algorithm to non-deterministic finite automata, and establish a relationship between this algorithm and the one proposed in Almeida et al. We also present some experimental comparative results. All these algorithms are closely related with the recent coalgebraic approach to automata proposed by Rutten.
Quantum mechanics from an equivalence principle
Energy Technology Data Exchange (ETDEWEB)
Faraggi, A.E. [Univ. of Florida, Gainesville, FL (United States). Inst. for Fundamental Theory; Matone, M. [Univ. of Padova (Italy)
1997-05-15
The authors show that requiring diffeomorphic equivalence for one-dimensional stationary states implies that the reduced action S{sub 0} satisfies the quantum Hamilton-Jacobi equation with the Planck constant playing the role of a covariantizing parameter. The construction shows the existence of a fundamental initial condition which is strictly related to the Moebius symmetry of the Legendre transform and to its involutive character. The universal nature of the initial condition implies the Schroedinger equation in any dimension.
Derived equivalences induced by good silting complexes
Breaz, Simion; Modoi, George Ciprian
2017-01-01
Consider a (possibly big) silting object $U$ in a derived category over a (dg-)algebra $A$. Under some fairly general appropriate hypotheses, we show that it induces derived equivalences between the derived category over $A$ and a localization of the derived category of dg-endomorphism algebra $B$ of $U$. If, in addition, $U$ is small then this localization is the whole derived category over $B$.
Global equivalent magnetization of the oceanic lithosphere
Dyment, J.; Choi, Y.; Hamoudi, M.; Lesur, V.; Thebault, E.
2015-11-01
As a by-product of the construction of a new World Digital Magnetic Anomaly Map over oceanic areas, we use an original approach based on the global forward modeling of seafloor spreading magnetic anomalies and their comparison to the available marine magnetic data to derive the first map of the equivalent magnetization over the World's ocean. This map reveals consistent patterns related to the age of the oceanic lithosphere, the spreading rate at which it was formed, and the presence of mantle thermal anomalies which affects seafloor spreading and the resulting lithosphere. As for the age, the equivalent magnetization decreases significantly during the first 10-15 Myr after its formation, probably due to the alteration of crustal magnetic minerals under pervasive hydrothermal alteration, then increases regularly between 20 and 70 Ma, reflecting variations in the field strength or source effects such as the acquisition of a secondary magnetization. As for the spreading rate, the equivalent magnetization is twice as strong in areas formed at fast rate than in those formed at slow rate, with a threshold at ∼40 km/Myr, in agreement with an independent global analysis of the amplitude of Anomaly 25. This result, combined with those from the study of the anomalous skewness of marine magnetic anomalies, allows building a unified model for the magnetic structure of normal oceanic lithosphere as a function of spreading rate. Finally, specific areas affected by thermal mantle anomalies at the time of their formation exhibit peculiar equivalent magnetization signatures, such as the cold Australian-Antarctic Discordance, marked by a lower magnetization, and several hotspots, marked by a high magnetization.
APTE: An Algorithm for Proving Trace Equivalence
Cheval, Vincent
2014-01-01
This paper presents APTE, a new tool for automatically proving the security of cryptographic protocols. It focuses on proving trace equivalence between processes, which is crucial for specifying privacy type properties such as anonymity and unlinkability.\\ud \\ud The tool can handle protocols expressed in a calculus similar to the applied-pi calculus, which allows us to capture most existing protocols that rely on classical cryptographic primitives. In particular, APTE handles private channels...
Two Tests for the Equivalence Principle
Harpaz, Amos
2011-06-01
The question: "Is the equivalence principle (EP) a general principle" is examined by analyzing solutions to two cases: 1. The Twin Paradox, and 2. Does a static charge located in a gravitational field radiate? The solutions to these two cases are given first by using EP, and then by physical analysis of the system involved. The fact that the two methods yield the same solutions, may be considered as test cases for the validity of the EP.
Equivalent Lagrangians: Generalization, Transformation Maps, and Applications
Directory of Open Access Journals (Sweden)
N. Wilson
2012-01-01
Full Text Available Equivalent Lagrangians are used to find, via transformations, solutions and conservation laws of a given differential equation by exploiting the possible existence of an isomorphic algebra of Lie point symmetries and, more particularly, an isomorphic Noether point symmetry algebra. Applications include ordinary differential equations such as the Kummer equation and the combined gravity-inertial-Rossbywave equation and certain classes of partial differential equations related to multidimensional wave equations.
Capacitors with low equivalent series resistance
Fleig, Patrick Franz (Inventor); Lakeman, Charles D. E. (Inventor); Fuge, Mark (Inventor)
2011-01-01
An electric double layer capacitor (EDLC) in a coin or button cell configuration having low equivalent series resistance (ESR). The capacitor comprises mesh or other porous metal that is attached via conducting adhesive to one or both the current collectors. The mesh is embedded into the surface of the adjacent electrode, thereby reducing the interfacial resistance between the electrode and the current collector, thus reducing the ESR of the capacitor.
Aerospace Applications of Non-Equilibrium Plasma
Blankson, Isaiah M.
2016-01-01
Nonequilibrium plasma/non-thermal plasma/cold plasmas are being used in a wide range of new applications in aeronautics, active flow control, heat transfer reduction, plasma-assisted ignition and combustion, noise suppression, and power generation. Industrial applications may be found in pollution control, materials surface treatment, and water purification. In order for these plasma processes to become practical, efficient means of ionization are necessary. A primary challenge for these applications is to create a desired non-equilibrium plasma in air by preventing the discharge from transitioning into an arc. Of particular interest is the impact on simulations and experimental data with and without detailed consideration of non-equilibrium effects, and the consequences of neglecting non-equilibrium. This presentation will provide an assessment of the presence and influence of non-equilibrium phenomena for various aerospace needs and applications. Specific examples to be considered will include the forward energy deposition of laser-induced non-equilibrium plasmoids for sonic boom mitigation, weakly ionized flows obtained from pulsed nanosecond discharges for an annular Hall type MHD generator duct for turbojet energy bypass, and fundamental mechanisms affecting the design and operation of novel plasma-assisted reactive systems in dielectric liquids (water purification, in-pipe modification of fuels, etc.).
Quantification of the power of Hardy-Weinberg equilibrium testing to detect genotyping error.
Cox, David G; Kraft, Peter
2006-01-01
Deviation from Hardy-Weinberg equilibrium has become an accepted test for genotyping error. While it is generally considered that testing departures from Hardy-Weinberg equilibrium to detect genotyping error is not sensitive, little has been done to quantify this sensitivity. Therefore, we have examined various models of genotyping error, including error caused by neighboring SNPs that degrade the performance of genotyping assays. We then calculated the power of chi-square goodness-of-fit tests for deviation from Hardy-Weinberg equilibrium to detect such error. We have also examined the affects of neighboring SNPs on risk estimates in the setting of case-control association studies. We modeled the power of departure from Hardy-Weinberg equilibrium as a test to detect genotyping error and quantified the effect of genotyping error on disease risk estimates. Generally, genotyping error does not generate sufficient deviation from Hardy-Weinberg equilibrium to be detected. As expected, genotyping error due to neighboring SNPs attenuates risk estimates, often drastically. For the moment, the most widely accepted method of detecting genotyping error is to confirm genotypes by sequencing and/or genotyping via a separate method. While these methods are fairly reliable, they are also costly and time consuming.
A new formulation of equivalent effective stratospheric chlorine (EESC
Directory of Open Access Journals (Sweden)
P. A. Newman
2007-09-01
Full Text Available Equivalent effective stratospheric chlorine (EESC is a convenient parameter to quantify the effects of halogens (chlorine and bromine on ozone depletion in the stratosphere. We show, discuss, and analyze a new formulation of EESC that now includes the effects of age-of-air dependent fractional release values and an age-of-air spectrum. This EESC can be more appropriately applied to various parts of the stratosphere because of this dependence on mean age-of-air. This new formulation provides quantitative estimates of EESC that can be directly related to inorganic chlorine and bromine throughout the stratosphere. In this paper, we first provide a detailed description of the EESC calculation. We then use this EESC formulation to estimate that human-produced ozone depleting substances will recover to 1980 levels in 2041 in the midlatitudes, and 2067 over Antarctica. These recovery dates are based upon the assumption that the international agreements for regulating ozone-depleting substances are adhered to. In addition to recovery dates, we also estimate the uncertainties and possible problems in the estimated times of recovery. The midlatitude recovery of 2041 has a 95% confidence uncertainty from 2028 to 2049, while the 2067 Antarctic recovery has a 95% confidence uncertainty from 2056 to 2078. The principal uncertainties are from the estimated mean age-of-air and fractional release values, and the assumption that these quantities are time independent. Using other model estimates of age decrease due to climate change, we estimate that midlatitude recovery may be significantly accelerated.
Dotov, D G; Kim, S; Frank, T D
2015-02-01
We derive explicit expressions for the non-equilibrium thermodynamical variables of a canonical-dissipative limit cycle oscillator describing rhythmic motion patterns of active systems. These variables are statistical entropy, non-equilibrium internal energy, and non-equilibrium free energy. In particular, the expression for the non-equilibrium free energy is derived as a function of a suitable control parameter. The control parameter determines the Hopf bifurcation point of the deterministic active system and describes the effective pumping of the oscillator. In analogy to the equilibrium free energy of the Landau theory, it is shown that the non-equilibrium free energy decays as a function of the control parameter. In doing so, a similarity between certain equilibrium and non-equilibrium phase transitions is pointed out. Data from an experiment on human rhythmic movements is presented. Estimates for pumping intensity as well as the thermodynamical variables are reported. It is shown that in the experiment the non-equilibrium free energy decayed when pumping intensity was increased, which is consistent with the theory. Moreover, pumping intensities close to zero could be observed at relatively slow intended rhythmic movements. In view of the Hopf bifurcation underlying the limit cycle oscillator model, this observation suggests that the intended limit cycle movements were actually more similar to trajectories of a randomly perturbed stable focus. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
Dannhauser, Walter
1980-01-01
Described is an experiment designed to provide an experimental basis for a unifying point of view (utilizing theoretical framework and chemistry laboratory experiments) for physical chemistry students. Three experiments are described: phase equilibrium, chemical equilibrium, and a test of the third law of thermodynamics. (Author/DS)
Valeriani, C.; Allen, R.J.; Morelli, M.J.; Frenkel, D.; ten Wolde, P.R.
2009-01-01
We present a method for computing stationary distributions for activated processes in equilibrium and non-equilibrium systems using Forward Flux Sampling (FFS). In this method, the stationary distributions are obtained directly from the rate constant calculations for the forward and backward
Equilibrium and pre-equilibrium calculations of cross-sections of (p ...
Indian Academy of Sciences (India)
Equilibrium and pre-equilibrium calculations of cross-sections of (, ) reactions on 89Y, 90Zr and 94Mo targets used for the production of 89Zr, 90Nb and 94Tc ... Bülent Ecevit University, 67100 Zonguldak, Turkey; Faculty of Arts and Science, Department of Physics, Osmaniye Korkut Ata University, Osmaniye, Turkey ...
Phase Equilibrium Modeling for Shale Production Simulation
DEFF Research Database (Denmark)
Sandoval Lemus, Diego Rolando
simulator, which was then used to assess the impact of the capillary pressure on phase behavior in oil and gas production from tight reservoirs. Since capillary pressure and adsorption occur simultaneously in shale, its combined effect was studied. A model comparison for high-pressure adsorption in shale...... is presented. The adsorption data in shale is generally scarce, therefore, additional capabilities besides the accuracy were considered in the comparison. The multicomponent potential theory of adsorption yields the best results. Moreover, it shows to be useful to extrapolate adsorption data for hydrocarbons...... calculation tools for phase equilibrium in porous media with capillary pressure and adsorption effects. Analysis using these tools have shown that capillary pressure and adsorption have non-negligible effects on phase equilibrium in shale. As general tools, they can be used to calculate phase equilibrium...
Module description of TOKAMAK equilibrium code MEUDAS
Energy Technology Data Exchange (ETDEWEB)
Suzuki, Masaei; Hayashi, Nobuhiko; Matsumoto, Taro; Ozeki, Takahisa [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment
2002-01-01
The analysis of an axisymmetric MHD equilibrium serves as a foundation of TOKAMAK researches, such as a design of devices and theoretical research, the analysis of experiment result. For this reason, also in JAERI, an efficient MHD analysis code has been developed from start of TOKAMAK research. The free boundary equilibrium code ''MEUDAS'' which uses both the DCR method (Double-Cyclic-Reduction Method) and a Green's function can specify the pressure and the current distribution arbitrarily, and has been applied to the analysis of a broad physical subject as a code having rapidity and high precision. Also the MHD convergence calculation technique in ''MEUDAS'' has been built into various newly developed codes. This report explains in detail each module in ''MEUDAS'' for performing convergence calculation in solving the MHD equilibrium. (author)
Non-equilibrium quantum heat machines
Alicki, Robert; Gelbwaser-Klimovsky, David
2015-11-01
Standard heat machines (engine, heat pump, refrigerator) are composed of a system (working fluid) coupled to at least two equilibrium baths at different temperatures and periodically driven by an external device (piston or rotor) sometimes called the work reservoir. The aim of this paper is to go beyond this scheme by considering environments which are stationary but cannot be decomposed into a few baths at thermal equilibrium. Such situations are important, for example in solar cells, chemical machines in biology, various realizations of laser cooling or nanoscopic machines driven by laser radiation. We classify non-equilibrium baths depending on their thermodynamic behavior and show that the efficiency of heat machines powered by them is limited by the generalized Carnot bound.
Non-Equilibrium Thermodynamics in Multiphase Flows
Mauri, Roberto
2013-01-01
Non-equilibrium thermodynamics is a general framework that allows the macroscopic description of irreversible processes. This book introduces non-equilibrium thermodynamics and its applications to the rheology of multiphase flows. The subject is relevant to graduate students in chemical and mechanical engineering, physics and material science. This book is divided into two parts. The first part presents the theory of non-equilibrium thermodynamics, reviewing its essential features and showing, when possible, some applications. The second part of this book deals with how the general theory can be applied to model multiphase flows and, in particular, how to determine their constitutive relations. Each chapter contains problems at the end, the solutions of which are given at the end of the book. No prior knowledge of statistical mechanics is required; the necessary prerequisites are elements of transport phenomena and on thermodynamics. “The style of the book is mathematical, but nonetheless it remains very re...
Communication: Microphase equilibrium and assembly dynamics
Zhuang, Yuan; Charbonneau, Patrick
2017-09-01
Despite many attempts, ordered equilibrium microphases have yet to be obtained in experimental colloidal suspensions. The recent computation of the equilibrium phase diagram of a microscopic, particle-based microphase former [Zhuang et al., Phys. Rev. Lett. 116, 098301 (2016)] has nonetheless found such mesoscale assemblies to be thermodynamically stable. Here, we consider their equilibrium and assembly dynamics. At intermediate densities above the order-disorder transition, we identify four different dynamical regimes and the structural changes that underlie the dynamical crossovers from one disordered regime to the next. Below the order-disorder transition, we also find that periodic lamellae are the most dynamically accessible of the periodic microphases. Our analysis thus offers a comprehensive view of the dynamics of disordered microphases and a route to the assembly of periodic microphases in a putative well-controlled, experimental system.
Interfaces at equilibrium: A guide to fundamentals.
Marmur, Abraham
2017-06-01
The fundamentals of the thermodynamics of interfaces are reviewed and concisely presented. The discussion starts with a short review of the elements of bulk thermodynamics that are also relevant to interfaces. It continues with the interfacial thermodynamics of two-phase systems, including the definition of interfacial tension and adsorption. Finally, the interfacial thermodynamics of three-phase (wetting) systems is discussed, including the topic of non-wettable surfaces. A clear distinction is made between equilibrium conditions, in terms of minimizing energies (internal, Gibbs or Helmholtz), and equilibrium indicators, in terms of measurable, intrinsic properties (temperature, chemical potential, pressure). It is emphasized that the equilibrium indicators are the same whatever energy is minimized, if the boundary conditions are properly chosen. Also, to avoid a common confusion, a distinction is made between systems of constant volume and systems with drops of constant volume. Copyright © 2016 Elsevier B.V. All rights reserved.
On financial equilibrium with intermediation costs
DEFF Research Database (Denmark)
Markeprand, Tobias Ejnar
2008-01-01
This paper studies the set of competitive equilibria in financial economies with intermediation costs. We consider an arbitrary dividend structure, which includes options and equity with limited liabilities.We show a general existence result and upper-hemi continuity of the equilibrium correspond......This paper studies the set of competitive equilibria in financial economies with intermediation costs. We consider an arbitrary dividend structure, which includes options and equity with limited liabilities.We show a general existence result and upper-hemi continuity of the equilibrium...... correspondence. Finally, we prove that when intermediation costs approach zero, unbounded volume of asset trades is a necessary and sufficient condition, provided that, there is no financial equilibrium without intermediation costs....
Relativistic perfect fluids in local thermal equilibrium
Coll, Bartolomé; Sáez, Juan Antonio
2016-01-01
The inverse problem for conservative perfect fluid energy tensors provides a striking result. Namely that, in spite of its name, its historic origin or its usual conceptualization, the notion of {\\em local thermal equilibrium} for a perfect fluid is a {\\em purely hydrodynamic}, not thermodynamic, notion. This means that it may be thought, defined and detected using exclusively hydrodynamic quantities, without reference to temperature or any other thermodynamic concept, either of equilibrium or irreversible: a relativistic perfect fluid evolves in local thermal equilibrium if, and only if, its hydrodynamic variables evolve keeping a certain relation among them. This relation fixes, but only fixes, a precise fraction of the thermodynamics of the fluid, namely that relating the speed of its sound waves to the hydrodynamic variables. All thermodynamic schemes (sets of thermodynamic variables and their mutual relations) compatible with such a relation on the sole hydrodynamic variables are obtained. This hydrodyna...
Equilibrium simulation of a small scale gasification biomass CHP plant
Energy Technology Data Exchange (ETDEWEB)
Baggio, M.; Baratieri, M.; Grigiante, M. (Department of Environmental and Civil Engineering, University of Trento (Italy))
2007-07-01
One of the most important issues, in assessing the performance of IC engines fueled with biomass synthesis gas, is to have a good evaluation of the energy content of the producer gas per unit volume; in fact, as these are volumetric machines, it can be expected that the relevant properties are those of the inflow gas air mixture. For this purpose, in the present study a multiphase thermodynamic equilibrium analysis has been carried out providing an estimate of the gas composition and the yield of char along the conversion process. The aim of the present paper is then to provide a realistic estimate of the global energy efficiency of the process, by means of a whole balance of plant simulation; therefore, the enthalpy fluxes arising from the different components have been evaluated using the chemical equilibrium analysis for the reacting stages. The performed plant analysis demonstrates how the proposed coupling of a gasification reactor with an IC gas engine presents high conversion efficiencies and seems to be particularly suitable for distributed energy production, especially in small towns situated in rural zones, where there is often available a large quantity of biomass waste. (orig.)
Bidzhiev, Kemal; Misguich, Grégoire
2017-11-01
We investigate the out-of-equilibrium properties of a simple quantum impurity model, the interacting resonant level model. We focus on the scaling regime, where the bandwidth of the fermions in the leads is larger than all the other energies, so that the lattice and the continuum versions of the model become equivalent. Using time-dependent density matrix renormalization group simulations initialized with states having different densities in the two leads, we extend the results of Boulat, Saleur, and Schmitteckert [Phys. Rev. Lett. 101, 140601 (2008), 10.1103/PhysRevLett.101.140601] concerning the current-voltage (I -V ) curves, for several values of the interaction strength U . We estimate numerically the Kondo scale TB and the exponent b (U ) associated to the tunneling of the fermions from the leads to the dot. Next, we analyze the quantum entanglement properties of the steady states. We focus in particular on the entropy rate α , describing the linear growth with time of the bipartite entanglement in the system. We show that, as for the current, α /TB is described by some function of U and of the rescaled bias V /TB . Finally, the spatial structure of the entropy profiles is discussed.
The effect of equivalence scales on poverty at Oblast level in Ukraine
Directory of Open Access Journals (Sweden)
Gianni Betti
2014-06-01
Full Text Available This paper aims at properly measuring and evaluating the impact of equivalence scales on poverty and inequality at both national and regional (Oblast level in Ukraine. A new equivalence scale set is proposed and estimated on the basis of the UHLSC data; for some regions the precision of the estimate results as not being sufficient due to small sub-sample sizes. A variant of EBLUP small area estimation technique is proposed and implemented to estimate poverty measures properly and to reduce standard errors of such estimates; the variant concerned is based on a ratio approach: in this way the effect of the difficult-to-qualify institutional and historical factors, common to the country and its regions, is abstracted.
46 CFR 42.20-12 - Conditions of equilibrium.
2010-10-01
... 46 Shipping 2 2010-10-01 2010-10-01 false Conditions of equilibrium. 42.20-12 Section 42.20-12... BY SEA Freeboards § 42.20-12 Conditions of equilibrium. The following conditions of equilibrium are... stability. Through an angle of 20 degrees beyond its position of equilibrium, the vessel must meet the...
Statistical equilibrium equations for trace elements in stellar atmospheres
Kubat, Jiri
2010-01-01
The conditions of thermodynamic equilibrium, local thermodynamic equilibrium, and statistical equilibrium are discussed in detail. The equations of statistical equilibrium and the supplementary equations are shown together with the expressions for radiative and collisional rates with the emphasize on the solution for trace elements.
14 CFR 67.305 - Ear, nose, throat, and equilibrium.
2010-01-01
... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Ear, nose, throat, and equilibrium. 67.305..., nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a third-class airman... by, or that may reasonably be expected to be manifested by, vertigo or a disturbance of equilibrium. ...
14 CFR 67.105 - Ear, nose, throat, and equilibrium.
2010-01-01
... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Ear, nose, throat, and equilibrium. 67.105..., nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a first-class airman... may reasonably be expected to be manifested by, vertigo or a disturbance of equilibrium. ...
14 CFR 67.205 - Ear, nose, throat, and equilibrium.
2010-01-01
... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Ear, nose, throat, and equilibrium. 67.205..., nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a second-class airman..., vertigo or a disturbance of equilibrium. ...
Directory of Open Access Journals (Sweden)
Zhimiao Tao
2013-01-01
Full Text Available An equilibrium chance-constrained multiobjective programming model with birandom parameters is proposed. A type of linear model is converted into its crisp equivalent model. Then a birandom simulation technique is developed to tackle the general birandom objective functions and birandom constraints. By embedding the birandom simulation technique, a modified genetic algorithm is designed to solve the equilibrium chance-constrained multiobjective programming model. We apply the proposed model and algorithm to a real-world inventory problem and show the effectiveness of the model and the solution method.
Particle Sorting and Motility Out of Equilibrium
Sandford, Cato
The theory of equilibrium statistical physics, formulated over a century ago, provides an excellent description of physical systems which have reached a static, relaxed state. Such systems can be loosely thought of as maximally disordered, in keeping with the Second Law of Thermodynamics which states that a thermal system in equilibrium has reached a state of highest entropy. However, many entities in the world around us maintain themselves in an remarkably ordered and dynamic state, and must pay for this by producing entropy in their surroundings. Organisms, for example, convert chemical energy (food) into heat, which is then dumped into the environment, raising its entropy. Systems which produce entropy through any mechanism must be described by theories of non-equilibrium statistical physics, for which there currently exists no unified framework or ontology. Here we examine two specific cases of non-equilibrium phenomena from a theoretical perspective. First, we explore the behaviour of microscopic particles which continually dissipate energy to propel themselves through their environment. Second, we consider how devices which distinguish between different types of particles can exploit non-equilibrium processes to enhance their performance. For the case of self-propelled particles, we consider a theoretical model where the particle's propulsion force has "memory"--it is a random process whose instantaneous value depends on its past evolution. This introduces a persistence in the particle's motion, and requires the dissipation of energy into its surroundings. These particles are found to exhibit a variety of behaviours forbidden in equilibrium systems: for instance they may cluster around barriers, exert unbalanced forces, and sustain steady flows through space. We develop the understanding of these particles' dynamics through a combination of explicit calculations, approximations and numerical simulation which characterise and quantify their non-equilibrium
Putting A Human Face on Equilibrium
Glickstein, Neil
2005-03-01
A short biography of chemist Fritz Haber is used to personalize the abstract concepts of equilibrium chemistry for high school students in an introductory course. In addition to giving the Haber Bosch process an historic, an economic, and a scientific background the reading and subsequent discussion allows students for whom the human perspective is of paramount importance a chance to investigate the irony of balance or equilibrium in Haber's life story. Since the inclusion of the Haber biography, performance in the laboratory and on examinations for those students who are usually only partially engaged has dramatically improved.
Quantum gambling based on Nash-equilibrium
Zhang, Pei; Zhou, Xiao-Qi; Wang, Yun-Long; Liu, Bi-Heng; Shadbolt, Pete; Zhang, Yong-Sheng; Gao, Hong; Li, Fu-Li; O'Brien, Jeremy L.
2017-06-01
The problem of establishing a fair bet between spatially separated gambler and casino can only be solved in the classical regime by relying on a trusted third party. By combining Nash-equilibrium theory with quantum game theory, we show that a secure, remote, two-party game can be played using a quantum gambling machine which has no classical counterpart. Specifically, by modifying the Nash-equilibrium point we can construct games with arbitrary amount of bias, including a game that is demonstrably fair to both parties. We also report a proof-of-principle experimental demonstration using linear optics.
Entropy and equilibrium via games of complexity
Topsøe, Flemming
2004-09-01
It is suggested that thermodynamical equilibrium equals game theoretical equilibrium. Aspects of this thesis are discussed. The philosophy is consistent with maximum entropy thinking of Jaynes, but goes one step deeper by deriving the maximum entropy principle from an underlying game theoretical principle. The games introduced are based on measures of complexity. Entropy is viewed as minimal complexity. It is demonstrated that Tsallis entropy ( q-entropy) and Kaniadakis entropy ( κ-entropy) can be obtained in this way, based on suitable complexity measures. A certain unifying effect is obtained by embedding these measures in a two-parameter family of entropy functions.
Stepwise kinetic equilibrium models of quantitative polymerase chain reaction.
Cobbs, Gary
2012-08-16
Numerous models for use in interpreting quantitative PCR (qPCR) data are present in recent literature. The most commonly used models assume the amplification in qPCR is exponential and fit an exponential model with a constant rate of increase to a select part of the curve. Kinetic theory may be used to model the annealing phase and does not assume constant efficiency of amplification. Mechanistic models describing the annealing phase with kinetic theory offer the most potential for accurate interpretation of qPCR data. Even so, they have not been thoroughly investigated and are rarely used for interpretation of qPCR data. New results for kinetic modeling of qPCR are presented. Two models are presented in which the efficiency of amplification is based on equilibrium solutions for the annealing phase of the qPCR process. Model 1 assumes annealing of complementary targets strands and annealing of target and primers are both reversible reactions and reach a dynamic equilibrium. Model 2 assumes all annealing reactions are nonreversible and equilibrium is static. Both models include the effect of primer concentration during the annealing phase. Analytic formulae are given for the equilibrium values of all single and double stranded molecules at the end of the annealing step. The equilibrium values are then used in a stepwise method to describe the whole qPCR process. Rate constants of kinetic models are the same for solutions that are identical except for possibly having different initial target concentrations. Analysis of qPCR curves from such solutions are thus analyzed by simultaneous non-linear curve fitting with the same rate constant values applying to all curves and each curve having a unique value for initial target concentration. The models were fit to two data sets for which the true initial target concentrations are known. Both models give better fit to observed qPCR data than other kinetic models present in the literature. They also give better estimates of
Stepwise kinetic equilibrium models of quantitative polymerase chain reaction
Directory of Open Access Journals (Sweden)
Cobbs Gary
2012-08-01
Full Text Available Abstract Background Numerous models for use in interpreting quantitative PCR (qPCR data are present in recent literature. The most commonly used models assume the amplification in qPCR is exponential and fit an exponential model with a constant rate of increase to a select part of the curve. Kinetic theory may be used to model the annealing phase and does not assume constant efficiency of amplification. Mechanistic models describing the annealing phase with kinetic theory offer the most potential for accurate interpretation of qPCR data. Even so, they have not been thoroughly investigated and are rarely used for interpretation of qPCR data. New results for kinetic modeling of qPCR are presented. Results Two models are presented in which the efficiency of amplification is based on equilibrium solutions for the annealing phase of the qPCR process. Model 1 assumes annealing of complementary targets strands and annealing of target and primers are both reversible reactions and reach a dynamic equilibrium. Model 2 assumes all annealing reactions are nonreversible and equilibrium is static. Both models include the effect of primer concentration during the annealing phase. Analytic formulae are given for the equilibrium values of all single and double stranded molecules at the end of the annealing step. The equilibrium values are then used in a stepwise method to describe the whole qPCR process. Rate constants of kinetic models are the same for solutions that are identical except for possibly having different initial target concentrations. Analysis of qPCR curves from such solutions are thus analyzed by simultaneous non-linear curve fitting with the same rate constant values applying to all curves and each curve having a unique value for initial target concentration. The models were fit to two data sets for which the true initial target concentrations are known. Both models give better fit to observed qPCR data than other kinetic models present in the
Directory of Open Access Journals (Sweden)
Muhammad Ridwan
2017-01-01
Full Text Available Bricks of low elastic modulus are occasionally used in some developing countries, such as Indonesia and India. Most of the previous research efforts focused on masonry structures built with bricks of considerably high elastic modulus. The objective of this study is to quantify the equivalent elastic modulus of lower-stiffness masonry structures, when the mortar has a higher modulus of elasticity than the bricks, by employing finite element (FE simulations and adopting the homogenization technique. The reported numerical simulations adopted the two-dimensional representative volume elements (RVEs using quadrilateral elements with four nodes. The equivalent elastic moduli of composite elements with various bricks and mortar were quantified. The numerically estimated equivalent elastic moduli from the FE simulations were verified using previously established test data. Hence, a new simplified formula for the calculation of the equivalent modulus of elasticity of such masonry structures is proposed in the present study.
Directory of Open Access Journals (Sweden)
Florentina Xhelili Krasniqi
2016-12-01
Full Text Available Nobel Laureates with their contributions to the development of the theory of general equilibrium have enabled this theory to be one of the most important for theoretical and practical analysis of the overall economy and the efficient use of economic resources. Results of the research showing that contributions of Nobel Laureates in the economy belong to two main frameworks of development of the general equilibrium theory: one was the mathematical model of general equilibrium developed by John R. Hicks (1939, Kenneth J.Arrow (1951 and Gerard Debreu (1954 and second frames of general equilibrium belongs to Paul A. Samuelson (1958. To highlight the contributions of these Nobel laureates in the development of the theory of general equilibrium have been selected and are presented in the paper some views, estimates and assumptions that have contributed not only in solving concrete problems, but also to the development of economic science in general. Their works represent a synthesis of theoretical and practical aspects of treatment of general equilibrium which are the starting point for further research in this field.
Equivalent Circuit Modeling of Hysteresis Motors
Energy Technology Data Exchange (ETDEWEB)
Nitao, J J; Scharlemann, E T; Kirkendall, B A
2009-08-31
We performed a literature review and found that many equivalent circuit models of hysteresis motors in use today are incorrect. The model by Miyairi and Kataoka (1965) is the correct one. We extended the model by transforming it to quadrature coordinates, amenable to circuit or digital simulation. 'Hunting' is an oscillatory phenomenon often observed in hysteresis motors. While several works have attempted to model the phenomenon with some partial success, we present a new complete model that predicts hunting from first principles.
Real Options Valuation Based on Certainty Equivalents
Directory of Open Access Journals (Sweden)
Cecilia Maya Ochoa
2014-12-01
Full Text Available This purpose of this research is to identify appropriate rates to discount the flows from real options in situations in which the risk-free rate does not apply, in particular, in incomplete markets. A methodology is proposed for valuing real options based on certainty equivalence, which requires as a principal condition the consideration of preferences represented with utility functions. A constant relative risk aversion (CRRA utility function is used to represent these preferences. The results indicate that this methodology adequately reflects how the value of a real option changes in accordance with an investor´s preferences.
Open maps, behavioural equivalences, and congruences
DEFF Research Database (Denmark)
Cheng, Allan; Nielsen, Mogens
1996-01-01
Spans of open maps have been proposed by Joyal, Nielsen, and Winskel as a way of adjoining an abstract equivalence, P-bisimilarity, to a category of models of computation M, where P is an arbitrary sub-category of observations. Part of the motivation was to recast and generalise Milner's well...... viewed as functors preserve P-bisimilarity? We define the notion of functors being P -factorisable, show how this ensures that P-bisimilarity is a congruence with respect to such functors. Guided by the definition of P-factorisability we show how it is possible to parametrise proofs of functors being P...
Galilean equivalence for galactic dark matter.
Kesden, Michael; Kamionkowski, Marc
2006-09-29
Satellite galaxies are tidally disrupted as they orbit the Milky Way. If dark matter (DM) experiences a stronger self-attraction than baryons, stars will preferentially gain rather than lose energy during tidal disruption, leading to an enhancement in the trailing compared to the leading tidal stream. The Sgr dwarf galaxy is seen to have roughly equal streams, challenging models in which DM and baryons accelerate differently by more than 10%. Future observations and a better understanding of DM distribution should allow detection of equivalence violation at the percent level.
Equivalent Circuit for Magnetoelectric Read and Write
Camsari, Kerem Y.; Faria, Rafatul; Hassan, Orchi; Sutton, Brian M.; Datta, Supriyo
2017-01-01
We describe an equivalent circuit model applicable to a wide variety of magnetoelectric phenomena and use SPICE simulations to benchmark this model against experimental data. We use this model to suggest a different mode of operation where the "1" and "0'" states are not represented by states with net magnetization (like $m_x$, $m_y$ or $m_z$) but by different easy axes, quantitatively described by ($m_x^2 - m_y^2$) which switches from "0" to "1" through the write voltage. This change is dire...
European Equivalencies in Legal Interpreting and Translation
DEFF Research Database (Denmark)
Corsellis, Ann; Hertog, Erik; Martinsen, Bodil
2002-01-01
Within Europe there is increasing freedom of movement between countries and increasing inward migration. As a result, equivalent standards of legl interpreting and translation are required to allow reliable communication for judicial cooperation between member states, for criminal and civil matters...... which cross national borders and for the needs of multilingual populations. The European Convention of Human Rights (article 6, paragrph 3) is one of the main planks of relevant legislation. This international, two year project has been funded by the EU Grotius programme to set out what is required...
Folz, E
1999-01-01
In most cases, sediments show inherent heterogeneity in their luminescence behaviours and bleaching histories, and identical aliquots are not available: single-aliquot determination of the equivalent dose (ED) is then the approach of choice and the advantages of using regenerative protocols are outlined. Experiments on five laboratory bleached and dosed quartz samples, following the protocol described by Murray and Roberts (1998. Measurement of the equivalent dose in quartz using a regenerative-dose single aliquot protocol. Radiation Measurements 27, 171-184), showed the hazards of using a single regeneration dose: a 10% variation in the regenerative dose yielded some equivalent dose estimates that differed from the expected value by more than 5%. A protocol is proposed that allows the use of different regenerative doses to bracket the estimated equivalent dose. The measured ED is found to be in excellent agreement with the known value when the main regeneration dose is within 10% of the true equivalent dose.
On the Existence of Evolutionary Learning Equilibriums
Directory of Open Access Journals (Sweden)
Masudul Alam Choudhury
2011-12-01
Full Text Available The usual kinds of Fixed-Point Theorems formalized on the existence of competitive equilibrium that explain much of economic theory at the core of economics can operate only on bounded and closed sets with convex mappings. But these conditions are hardly true of the real world of economic and financial complexities and perturbations. The category of learning sets explained by continuous fields of interactive, integrative and evolutionary behaviour caused by dynamic preferences at the individual and institutional and social levels cannot maintain the assumption of closed, bounded and convex sets. Thus learning sets and multi-system inter-temporal relations explained by pervasive complementarities and participation between variables and entities, and evolution by learning, have evolutionary equilibriums. Such a study requires a new methodological approach. This paper formalizes such a methodology for evolutionary equilibriums in learning spaces. It briefly points out the universality of learning equilibriums in all mathematical structures. For a particular case though, the inter-systemic interdependence between sustainable development and ethics and economics in the specific understanding of learning domain is pointed out.
Chronic dehydration affects hydroelectrolytic equilibrium and ...
African Journals Online (AJOL)
Chronic dehydration affects hydroelectrolytic equilibrium and adrenal gland morphology in wistar rat: comparison with Gerbillus tarabuli. ... given free access to tap water); ii) dehydrated rats (n=8) given 2% NaCl solution ad libitum for 7 days and (iii) G.tarabuli (n=6) given barely seeds ad libitum without access to water.
Group Contribution Methods for Phase Equilibrium Calculations.
Gmehling, Jürgen; Constantinescu, Dana; Schmid, Bastian
2015-01-01
The development and design of chemical processes are carried out by solving the balance equations of a mathematical model for sections of or the whole chemical plant with the help of process simulators. For process simulation, besides kinetic data for the chemical reaction, various pure component and mixture properties are required. Because of the great importance of separation processes for a chemical plant in particular, a reliable knowledge of the phase equilibrium behavior is required. The phase equilibrium behavior can be calculated with the help of modern equations of state or g(E)-models using only binary parameters. But unfortunately, only a very small part of the experimental data for fitting the required binary model parameters is available, so very often these models cannot be applied directly. To solve this problem, powerful predictive thermodynamic models have been developed. Group contribution methods allow the prediction of the required phase equilibrium data using only a limited number of group interaction parameters. A prerequisite for fitting the required group interaction parameters is a comprehensive database. That is why for the development of powerful group contribution methods almost all published pure component properties, phase equilibrium data, excess properties, etc., were stored in computerized form in the Dortmund Data Bank. In this review, the present status, weaknesses, advantages and disadvantages, possible applications, and typical results of the different group contribution methods for the calculation of phase equilibria are presented.
Static Equilibrium Configurations of Charged Metallic Bodies
African Journals Online (AJOL)
Rwanda Journal, Volume 27 Series C, 2012: Mathematical Sciences, Engineering and Technology. 13 electromagnetic phenomena is highly needed. This paper studied one of these phenomena, the static equilibrium configurations of charged metallic bodies. The mathematical model of the problem that we investigate in ...
Non-equilibrium thermodynamics and physical kinetics
Bikkin, Halid
2014-01-01
This graduate textbook covers contemporary directions of non-equilibrium statistical mechanics as well as classical methods of kinetics. With one of the main propositions being to avoid terms such as "obviously" and "it is easy to show", this treatise is an easy-to-read introduction into this traditional, yet vibrant field.
Considerations on the genetic equilibrium law
Camosso, Simone
2016-01-01
In the first part of the paper I will present a brief review on the Hardy-Weinberg equilibrium and its formulation in projective algebraic geometry. In the second and last part I will discuss examples and generalizations on the topic.
A Progression of Static Equilibrium Laboratory Exercises
Kutzner, Mickey; Kutzner, Andrew
2013-01-01
Although simple architectural structures like bridges, catwalks, cantilevers, and Stonehenge have been integral in human societies for millennia, as have levers and other simple tools, modern students of introductory physics continue to grapple with Newton's conditions for static equilibrium. As formulated in typical introductory physics…
Equilibrium-torus bifurcation in nonsmooth systems
DEFF Research Database (Denmark)
Zhusubahyev, Z.T.; Mosekilde, Erik
2008-01-01
in the phase space. The disappearance of the equilibrium point is accompanied by the soft appearance of an unstable focus period-1 orbit surrounded by a resonant or ergodic torus. Detailed numerical calculations are supported by a theoretical investigation of the normal form map that represents the piecewise...
Evolution and non-equilibrium physics
DEFF Research Database (Denmark)
Becker, Nikolaj; Sibani, Paolo
2014-01-01
We argue that the stochastic dynamics of interacting agents which replicate, mutate and die constitutes a non-equilibrium physical process akin to aging in complex materials. Specifically, our study uses extensive computer simulations of the Tangled Nature Model (TNM) of biological evolution...
Micro Data and General Equilibrium Models
DEFF Research Database (Denmark)
Browning, Martin; Hansen, Lars Peter; Heckman, James J.
1999-01-01
economic models, assesses the discordance between the macromodels used in policy evaluation and the microeconomic models used to generate the empirical evidence. For concreteness, we focus on two general equilibrium models: the stochastic growth model extended to include some forms of heterogeneity...
Rumor Propagation Model: An Equilibrium Study
Directory of Open Access Journals (Sweden)
José Roberto C. Piqueira
2010-01-01
information is analogous phenomena. Here, in an analogy with the SIR (Susceptible-Infected-Removed epidemiological model, the ISS (Ignorant-Spreader-Stifler rumor spreading model is studied. By using concepts from the Dynamical Systems Theory, stability of equilibrium points is established, according to propagation parameters and initial conditions. Some numerical experiments are conducted in order to validate the model.
A variational principle for vector equilibrium problems
Indian Academy of Sciences (India)
Home; Journals; Proceedings – Mathematical Sciences; Volume 111; Issue 4. A Variational Principle for Vector Equilibrium Problems. K R Kazmi. Volume 111 Issue 4 November 2001 pp 465-470. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/pmsc/111/04/0465-0470. Keywords.
An equilibrium profile model for tidal environments
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A. M. Bernabeu
2002-12-01
Full Text Available During a full tidal cycle, the beach profile is exposed to continuously changing hydrodynamical conditions. Consequently, the profile evolves constantly to adapt to these changes. The equilibrium condition on tidal beaches is defined in terms of the relative occurrence of swash, surf zone and shoaling processes. We have assumed that the tidal beach profile is in equilibrium when the net sediment transport along a tidal cycle is zero. In this model the contribution of swash is considered negligible. A simple and easy-to-apply equilibrium profile formulation is proposed. This model is based on the assumption that surf zone processes dominate the profile morphology wherever wave breaking occurs during the tidal cycle. The obtained equilibrium profile is valid from the high tide level to the breaker point at low tide level. The tidal influence on the profile morphology is the lengthening of the surf profile. The higher the tidal range, the longer the surf profile. The model was tested against field and laboratory data, showing reasonable predictions of measured beach profiles.
An equilibrium closure result for discontinuous games
Balder, E.J.
2011-01-01
For games with discontinuous payoffs Simon and Zame (1990) introduced payoff indeterminacy, in the form of endogenous sharing rules, which are measurable selections of a certain payoff correspondence. Their main result concerns the existence of a mixed Nash equilibrium and an associated sharing
Climate change as (dis)equilibrium
DEFF Research Database (Denmark)
Tejsner, Pelle; Veldhuis, Djuke
2018-01-01
Despite the evident challenges posed by arctic environments past and present, and despite the widespread acknowledgement that human population histories in the Arctic have historically been quite dynamic, it is often assumed that traditional pre-colonial populations were in perfect equilibrium wi...
Monetary Policy Frameworks and Real Equilibrium Determinacy
DEFF Research Database (Denmark)
Jensen, Henrik
2002-01-01
In a simple "prototype" model of monetary policymaking, I examine the issue of real equilibrium determinacy under targeting and instrument rules. The former framework involves minimization of a loss function (under discretion or commitment), whereas the latter involves commitment to an interest...
Measuring productivity differences in equilibrium search models
DEFF Research Database (Denmark)
Lanot, Gauthier; Neumann, George R.
1996-01-01
Equilibrium search models require unobserved heterogeneity in productivity to fit observed wage distribution data, but provide no guidance about the location parameter of the heterogeneity. In this paper we show that the location of the productivity heterogeneity implies a mode in a kernel density...
Static Equilibrium Configurations of Charged Metallic Bodies ...
African Journals Online (AJOL)
When charged particles are placed on an uncharged metallic body, the charged particles redistribute themselves along the surface of the body until they reach a point or a configuration that no net tangential force is experienced on each particle. That point is referred to as electrostatic equilibrium configuration or simply as ...
Spontaneity and Equilibrium II: Multireaction Systems
Raff, Lionel M.
2014-01-01
The thermodynamic criteria for spontaneity and equilibrium in multireaction systems are developed and discussed. When N reactions are occurring simultaneously, it is shown that G and A will depend upon N independent reaction coordinates, ?a (a = 1,2, ..., N), in addition to T and p for G or T and V for A. The general criteria for spontaneity and…
General Equilibrium Models: Improving the Microeconomics Classroom
Nicholson, Walter; Westhoff, Frank
2009-01-01
General equilibrium models now play important roles in many fields of economics including tax policy, environmental regulation, international trade, and economic development. The intermediate microeconomics classroom has not kept pace with these trends, however. Microeconomics textbooks primarily focus on the insights that can be drawn from the…
Bayesian equilibrium inference in the Minerva framework
Svensson, Jakob; Ford, Oliver; Kwak, Sehyun; Appel, Lynton; Rahbarnia, Kian; Geiger, Joachim; Schilling, Jonathan
2017-10-01
The Minerva framework is a scientific modelling system based on Bayesian forward modelling and is used at a number of experiments. The structure of the framework makes it possible to combine flux function based, axisymmetric or full 3D models. A general modularity approach makes it easy to replace underlying physics models, such as the model for force balance and corresponding current distribution. We will give an overview of the different models within Minerva for inference of equilibrium field and flux surfaces, for both tokamaks and stellarators. For axisymmetric devices, three methods of increasing complexity, Gaussian process based Current Tomography (CT), an iterative Grad-Shafranov solver, and a full nonlinear Grad-Shafranov based model, will be demonstrated for the JET device. The novel nonlinear Grad-Sharanov model defines a proper posterior distribution for the equilibrium problem thus defines the space of possible equilibrium solutions, and has the capacity to include any nonlinear constraints (e.g. from models of profile diagnostics). The Bayesian approach further allows uncertainties on the equilibrium parameters to be calculated. For the W7-X stellarator, two models based on the VMEC 3D solver and a fast function parameterization approximation will be demonstrated.
Directory of Open Access Journals (Sweden)
Florin-Marius PAVELESCU
2011-12-01
Full Text Available This paper deals with the consequences of the extension of the number of markets that are taken into consideration in a non-Walrasian equilibrium model. It is reviewed the initial content of the theory of non-Walrasian equilibrium and emphasizes the main modelling factors of the respective equilibrium. It proposes the inclusion of the capital market in the model of non-Walrasian equilibrium and is also reveals the implications of the extension of the respective model to the classification of types of non-Walrasian equilibrium and to the content of macroeconomic and structural policies. Also, it proposes an econometric method for the estimation of the type of unemployment. The respective methodology is practically used in the case of Romania for the period 1991-2004.
Thermal Equilibrium of a Macroscopic Quantum System in a Pure State.
Goldstein, Sheldon; Huse, David A; Lebowitz, Joel L; Tumulka, Roderich
2015-09-04
We consider the notion of thermal equilibrium for an individual closed macroscopic quantum system in a pure state, i.e., described by a wave function. The macroscopic properties in thermal equilibrium of such a system, determined by its wave function, must be the same as those obtained from thermodynamics, e.g., spatial uniformity of temperature and chemical potential. When this is true we say that the system is in macroscopic thermal equilibrium (MATE). Such a system may, however, not be in microscopic thermal equilibrium (MITE). The latter requires that the reduced density matrices of small subsystems be close to those obtained from the microcanonical, equivalently the canonical, ensemble for the whole system. The distinction between MITE and MATE is particularly relevant for systems with many-body localization for which the energy eigenfuctions fail to be in MITE while necessarily most of them, but not all, are in MATE. We note, however, that for generic macroscopic systems, including those with MBL, most wave functions in an energy shell are in both MATE and MITE. For a classical macroscopic system, MATE holds for most phase points on the energy surface, but MITE fails to hold for any phase point.
Selfish routing equilibrium in stochastic traffic network: A probability-dominant description.
Zhang, Wenyi; He, Zhengbing; Guan, Wei; Ma, Rui
2017-01-01
This paper suggests a probability-dominant user equilibrium (PdUE) model to describe the selfish routing equilibrium in a stochastic traffic network. At PdUE, travel demands are only assigned to the most dominant routes in the same origin-destination pair. A probability-dominant rerouting dynamic model is proposed to explain the behavioral mechanism of PdUE. To facilitate applications, the logit formula of PdUE is developed, of which a well-designed route set is not indispensable and the equivalent varitional inequality formation is simple. Two routing strategies, i.e., the probability-dominant strategy (PDS) and the dominant probability strategy (DPS), are discussed through a hypothetical experiment. It is found that, whether out of insurance or striving for perfection, PDS is a better choice than DPS. For more general cases, the conducted numerical tests lead to the same conclusion. These imply that PdUE (rather than the conventional stochastic user equilibrium) is a desirable selfish routing equilibrium for a stochastic network, given that the probability distributions of travel time are available to travelers.
Selfish routing equilibrium in stochastic traffic network: A probability-dominant description
Zhang, Wenyi; Guan, Wei; Ma, Rui
2017-01-01
This paper suggests a probability-dominant user equilibrium (PdUE) model to describe the selfish routing equilibrium in a stochastic traffic network. At PdUE, travel demands are only assigned to the most dominant routes in the same origin-destination pair. A probability-dominant rerouting dynamic model is proposed to explain the behavioral mechanism of PdUE. To facilitate applications, the logit formula of PdUE is developed, of which a well-designed route set is not indispensable and the equivalent varitional inequality formation is simple. Two routing strategies, i.e., the probability-dominant strategy (PDS) and the dominant probability strategy (DPS), are discussed through a hypothetical experiment. It is found that, whether out of insurance or striving for perfection, PDS is a better choice than DPS. For more general cases, the conducted numerical tests lead to the same conclusion. These imply that PdUE (rather than the conventional stochastic user equilibrium) is a desirable selfish routing equilibrium for a stochastic network, given that the probability distributions of travel time are available to travelers. PMID:28829834
Integrable topological billiards and equivalent dynamical systems
Vedyushkina, V. V.; Fomenko, A. T.
2017-08-01
We consider several topological integrable billiards and prove that they are Liouville equivalent to many systems of rigid body dynamics. The proof uses the Fomenko-Zieschang theory of invariants of integrable systems. We study billiards bounded by arcs of confocal quadrics and their generalizations, generalized billiards, where the motion occurs on a locally planar surface obtained by gluing several planar domains isometrically along their boundaries, which are arcs of confocal quadrics. We describe two new classes of integrable billiards bounded by arcs of confocal quadrics, namely, non-compact billiards and generalized billiards obtained by gluing planar billiards along non-convex parts of their boundaries. We completely classify non-compact billiards bounded by arcs of confocal quadrics and study their topology using the Fomenko invariants that describe the bifurcations of singular leaves of the additional integral. We study the topology of isoenergy surfaces for some non-convex generalized billiards. It turns out that they possess exotic Liouville foliations: the integral trajectories of the billiard that lie on some singular leaves admit no continuous extension. Such billiards appear to be leafwise equivalent to billiards bounded by arcs of confocal quadrics in the Minkowski metric.
Equivalent Relaxations of Optimal Power Flow
Energy Technology Data Exchange (ETDEWEB)
Bose, S; Low, SH; Teeraratkul, T; Hassibi, B
2015-03-01
Several convex relaxations of the optimal power flow (OPF) problem have recently been developed using both bus injection models and branch flow models. In this paper, we prove relations among three convex relaxations: a semidefinite relaxation that computes a full matrix, a chordal relaxation based on a chordal extension of the network graph, and a second-order cone relaxation that computes the smallest partial matrix. We prove a bijection between the feasible sets of the OPF in the bus injection model and the branch flow model, establishing the equivalence of these two models and their second-order cone relaxations. Our results imply that, for radial networks, all these relaxations are equivalent and one should always solve the second-order cone relaxation. For mesh networks, the semidefinite relaxation and the chordal relaxation are equally tight and both are strictly tighter than the second-order cone relaxation. Therefore, for mesh networks, one should either solve the chordal relaxation or the SOCP relaxation, trading off tightness and the required computational effort. Simulations are used to illustrate these results.
Tohyama, M.
1986-07-01
The equivalent sound absorption area in a rectangular reverberant room can be derived from the initial first and second derivatives (initial decay rate of the time derivative) of the ensemble and space-averaged sound energy decay curve. At low frequency bands, how to estimate the equivalent sound absorption area from the reverberation time has not been theoretically interpreted. This is because the decay curve is not linear in logarithmic scales. The formula for the absorption area derived here, however, does not contain the reverberation time. It shows the theoretical relation between the absorption area and the initial slopes of the decay curve. The equivalent absorption area and averaged damping constants can be estimated theoretically according to the relation derived here for low frequency bands.
Experimental Evaluation of Equivalent-Fluid Models for Melamine Foam
Allen, Albert R.; Schiller, Noah H.
2016-01-01
Melamine foam is a soft porous material commonly used in noise control applications. Many models exist to represent porous materials at various levels of fidelity. This work focuses on rigid frame equivalent fluid models, which represent the foam as a fluid with a complex speed of sound and density. There are several empirical models available to determine these frequency dependent parameters based on an estimate of the material flow resistivity. Alternatively, these properties can be experimentally educed using an impedance tube setup. Since vibroacoustic models are generally sensitive to these properties, this paper assesses the accuracy of several empirical models relative to impedance tube measurements collected with melamine foam samples. Diffuse field sound absorption measurements collected using large test articles in a laboratory are also compared with absorption predictions determined using model-based and measured foam properties. Melamine foam slabs of various thicknesses are considered.
Arias, E.; Florez, E.; Pérez-Torres, J. F.
2017-06-01
A new algorithm for the determination of equilibrium structures suitable for metal nanoclusters is proposed. The algorithm performs a stochastic search of the minima associated with the nuclear potential energy function restricted to a sphere (similar to the Thomson problem), in order to guess configurations of the nuclear positions. Subsequently, the guessed configurations are further optimized driven by the total energy function using the conventional gradient descent method. This methodology is equivalent to using the valence shell electron pair repulsion model in guessing initial configurations in the traditional molecular quantum chemistry. The framework is illustrated in several clusters of increasing complexity: Cu7, Cu9, and Cu11 as benchmark systems, and Cu38 and Ni9 as novel systems. New equilibrium structures for Cu9, Cu11, Cu38, and Ni9 are reported.
SWEAT: Snow Water Equivalent with AlTimetry
Agten, Dries; Benninga, Harm-Jan; Diaz Schümmer, Carlos; Donnerer, Julia; Fischer, Georg; Henriksen, Marie; Hippert Ferrer, Alexandre; Jamali, Maryam; Marinaci, Stefano; Mould, Toby JD; Phelan, Liam; Rosker, Stephanie; Schrenker, Caroline; Schulze, Kerstin; Emanuel Telo Bordalo Monteiro, Jorge
2017-04-01
To study how the water cycle changes over time, satellite and airborne remote sensing missions are typically employed. Over the last 40 years of satellite missions, the measurement of true water inventories stored in sea and land ice within the cryosphere have been significantly hindered by uncertainties introduced by snow cover. Being able to determine the thickness of this snow cover would act to reduce such error, improving current estimations of hydrological and climate models, Earth's energy balance (albedo) calculations and flood predictions. Therefore, the target of the SWEAT (Snow Water Equivalent with AlTimetry) mission is to directly measure the surface Snow Water Equivalent (SWE) on sea and land ice within the polar regions above 60°and below -60° latitude. There are no other satellite missions currently capable of directly measuring SWE. In order to achieve this, the proposed mission will implement a novel combination of Ka- and Ku-band radioaltimeters (active microwave sensors), capable of penetrating into the snow microstructure. The Ka-band altimeter (λ ≈ 0.8 cm) provides a low maximum snow pack penetration depth of up to 20 cm for dry snow at 37 GHz, since the volume scattering of snow dominates over the scattering caused by the underlying ice surface. In contrast, the Ku-band altimeter (λ ≈ 2 cm) provides a high maximum snowpack penetration depth of up to 15 m in high latitudes regions with dry snow, as volume scattering is decreased by a factor of 55. The combined difference in Ka- and Ku-band signal penetration results will provide more accurate and direct determination of SWE. Therefore, the SWEAT mission aims to improve estimations of global SWE interpreted from passive microwave products, and improve the reliability of numerical snow and climate models.
Chemical Reactions Using a Non-Equilibrium Wigner Function Approach
Directory of Open Access Journals (Sweden)
Ramón F. Álvarez-Estrada
2016-10-01
Full Text Available A three-dimensional model of binary chemical reactions is studied. We consider an ab initio quantum two-particle system subjected to an attractive interaction potential and to a heat bath at thermal equilibrium at absolute temperature T > 0 . Under the sole action of the attraction potential, the two particles can either be bound or unbound to each other. While at T = 0 , there is no transition between both states, such a transition is possible when T > 0 (due to the heat bath and plays a key role as k B T approaches the magnitude of the attractive potential. We focus on a quantum regime, typical of chemical reactions, such that: (a the thermal wavelength is shorter than the range of the attractive potential (lower limit on T and (b ( 3 / 2 k B T does not exceed the magnitude of the attractive potential (upper limit on T. In this regime, we extend several methods previously applied to analyze the time duration of DNA thermal denaturation. The two-particle system is then described by a non-equilibrium Wigner function. Under Assumptions (a and (b, and for sufficiently long times, defined by a characteristic time scale D that is subsequently estimated, the general dissipationless non-equilibrium equation for the Wigner function is approximated by a Smoluchowski-like equation displaying dissipation and quantum effects. A comparison with the standard chemical kinetic equations is made. The time τ required for the two particles to transition from the bound state to unbound configurations is studied by means of the mean first passage time formalism. An approximate formula for τ, in terms of D and exhibiting the Arrhenius exponential factor, is obtained. Recombination processes are also briefly studied within our framework and compared with previous well-known methods.
Equilibrium Temperature of a Satellite in LowEarth Orbit
Directory of Open Access Journals (Sweden)
T. M. Hegab
2015-01-01
Full Text Available The efficiency of artificial satellite equipment, essentially, depends on its temperature condition, which in the case of low-Earth orbit varies quite widely. The satellite temperature changes because of the fact that along with a portion of the orbit where the satellite perceives heat flows, caused by solar radiation directly incident on its surface and solar radiation, reflected from the Earth's surface; in general cases of the low earth orbit there is its shaded portion where the satellite receives only a relatively low intensive self-radiation of the Earth. The level of possible values of satellite temperature at different portions of low earth orbit can be estimated by the equilibrium temperature determined from the balance equation of heat flows, perceived and radiated by its surface.The analysis of heat flows, which act on the surface of an artificial satellite of conditional spherical shape, allows us to obtain the dependences, in order to find a satellite equilibrium temperature at different heights of its position above Earth's surface and an angle between the directions from the center of the Earth towards the Sun, and the satellite as it moves out of the shadow of the Earth and at different height of its position at the shaded portion of the orbit as well. These dependencies are used for graphing to show the changes of the equilibrium temperature of the low-Earth orbiting satellite.The presented technique allows us to evaluate the possible range of temperature change of the low-Earth orbiting satellite.
Equilibrium shoreline response of a high wave energy beach
Yates, M.L.; Guza, R.T.; O'Reilly, W. C.; Hansen, J.E.; Barnard, P.L.
2011-01-01
Four years of beach elevation surveys at Ocean Beach, San Francisco, California, are used to extend an existing equilibrium shoreline change model, previously calibrated with fine sand and moderate energy waves, to medium sand and higher-energy waves. The shoreline, characterized as the cross-shore location of the mean high water contour, varied seasonally by between 30 and 60 m, depending on the alongshore location. The equilibrium shoreline change model relates the rate of horizontal shoreline displacement to the hourly wave energy E and the wave energy disequilibrium, the difference between E and the equilibrium wave energy that would cause no change in the present shoreline location. Values for the model shoreline response coefficients are tuned to fit the observations in 500 m alongshore segments and averaged over segments where the model has good skill and the estimated effects of neglected alongshore sediment transport are relatively small. Using these representative response coefficients for 0.3 mm sand from Ocean Beach and driving the model with much lower-energy winter waves observed at San Onofre Beach (also 0.3 mm sand) in southern California, qualitatively reproduces the small seasonal shoreline fluctuations at San Onofre. This consistency suggests that the shoreline model response coefficients depend on grain size and may be constant, and thus transportable, between sites with similar grain size and different wave climates. The calibrated model response coefficients predict that for equal fluctuations in wave energy, changes in shoreline location on a medium-grained (0.3 mm) beach are much smaller than on a previously studied fine-grained (0.2 mm) beach. Copyright ?? 2011 by the American Geophysical Union.
Equilibrium water and solute uptake in silicone hydrogels.
Liu, D E; Dursch, T J; Oh, Y; Bregante, D T; Chan, S Y; Radke, C J
2015-05-01
Equilibrium water content of and solute partitioning in silicone hydrogels (SiHys) are investigated using gravimetric analysis, fluorescence confocal laser-scanning microscopy (FCLSM), and back extraction with UV/Vis-absorption spectrophotometry. Synthesized silicone hydrogels consist of silicone monomer, hydrophilic monomer, cross-linking agent, and triblock-copolymer macromer used as an amphiphilic compatibilizer to prevent macrophase separation. In all cases, immiscibility of the silicone and hydrophilic polymers results in microphase-separated morphologies. To investigate solute uptake in each of the SiHy microphases, equilibrium partition coefficients are obtained for two hydrophilic solutes (i.e., theophylline and caffeine dissolved in aqueous phosphate-buffered saline) and two oleophilic solutes (i.e., Nile Red and Bodipy Green dissolved in silicone oil), respectively. Measured water contents and aqueous-solute partition coefficients increase linearly with increasing solvent-free hydrophilic-polymer volume fraction. Conversely, oleophilic-solute partition coefficients decrease linearly with rising solvent-free hydrophilic-polymer volume fraction (i.e., decreasing hydrophobic silicone-polymer fraction). We quantitatively predict equilibrium SiHy water and solute uptake assuming that water and aqueous solutes reside only in hydrophilic microdomains, whereas oleophilic solutes partition predominately into silicone microdomains. Predicted water contents and solute partition coefficients are in excellent agreement with experiment. Our new procedure permits a priori estimation of SiHy water contents and solute partition coefficients based solely on properties of silicone and hydrophilic homopolymer hydrogels, eliminating the need for further mixed-polymer-hydrogel experiments. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Chisari, Omar O.; Martin Cicowiez
2010-01-01
We estimate the Marginal Cost of Public Funds for Argentina using a Computable General Equilibrium (CGE) model, assessing the sensitivity of the results to the existence of alternative regulatory regimes (price-cap and cost-plus) for public utilities subject to regulation. The estimates are in the range of international studies, and we confirm that the results are sensitive to the regulatory regime, to the presence of exempted goods, the existence of unemployment, the elasticity of labor supp...
Equilibrium and non-equilibrium electron tunneling via discrete quantum states
Deshmukh, Mandar M.; Bonet, Edgar; Pasupathy, A. N.; Ralph, D. C.
2001-01-01
Tunneling is measured via the quantum levels of a metal nanoparticle. We analyze quantitatively the resonance energies, widths, and amplitudes, both in the regime where only one state is accessible for tunneling and in the non-equilibrium regime when additional states are made accessible one-by-one. For tunneling through one state, our results agree with expectations for sequential tunneling, but in the non-equilibrium regime the resonances are broadened and shifted in ways that require takin...
Premetric equivalent of general relativity: Teleparallelism
Itin, Yakov; Hehl, Friedrich W.; Obukhov, Yuri N.
2017-04-01
In general relativity (GR), the metric tensor of spacetime is essential since it represents the gravitational potential. In other gauge theories (such as electromagnetism), the so-called premetric approach succeeds in separating the purely topological field equation from the metric-dependent constitutive law. We show here that GR allows for a premetric formulation, too. For this purpose, we apply the teleparallel approach of gravity, which represents GR as a gauge theory based on the translation group. We formulate the metric-free topological field equation and a general linear constitutive law between the basic field variables. The requirement of local Lorentz invariance turns the model into a full equivalent of GR. Our approach opens a way for a natural extension of GR to diverse geometrical structures of spacetime.
Characterization of Destrins with Different Dextrose Equivalents
Directory of Open Access Journals (Sweden)
Guanglei Li
2010-07-01
Full Text Available Dextrins are widely used for their functional properties and prepared by partial hydrolysis of starch using acid, enzymes, or combinations of both. The physiochemical properties of dextrins are dependent on their molecular distribution and oligosaccharide profiles. In this study, scanning electron microscopy (SEM, X-ray diffractometry (XRD, rapid viscoanalysis (RVA, high-performance Liquid Chromatography (HPLC and gel permeation chromatography (GPC were used to characterize dextrins prepared by common neutral and thermostable α-amylase hydrolysis. The dextrin granules displayed irregular surfaces and were badly damaged by the enzyme treatment. They displayed A-type X-ray diffraction patterns with a decrease of intensity of the characteristic diffraction peaks. The RVA profiles showed that the viscosity of dextrin decreased with the increase of its Dextrose Equivalent (DE value. According to HPLC analysis, the molecular weight, degree of polymerization and the composition of oligosaccharides in dextrins were different.
Expressivism, Relativism and the analytic equivalence test
Directory of Open Access Journals (Sweden)
Maria J. Frapolli
2015-11-01
Full Text Available The purpose of this paper is to show that, pace (Field 2009, 252, MacFarlane’s assessment relativism and expressivism should be sharply distinguished. We do so by arguing that relativism and expressivism exemplify two very different approaches to context-dependence. Relativism, on the one hand, shares with other contemporary approaches a bottom-up, building block, model, while expressivism is part of a different tradition, one that might include Lewis’ epistemic contextualism and Frege’s content individuation, with which it shares an organic model to deal with context-dependence. The building-block model and the organic model, and thus relativism and expressivism, are set apart with the aid of a particular test: only the building-block model is compatible with the idea that there might be analytically equivalent, and yet different, propositions.
Expressivism, Relativism, and the Analytic Equivalence Test.
Frápolli, Maria J; Villanueva, Neftalí
2015-01-01
The purpose of this paper is to show that, pace (Field, 2009), MacFarlane's assessment relativism and expressivism should be sharply distinguished. We do so by arguing that relativism and expressivism exemplify two very different approaches to context-dependence. Relativism, on the one hand, shares with other contemporary approaches a bottom-up, building block, model, while expressivism is part of a different tradition, one that might include Lewis' epistemic contextualism and Frege's content individuation, with which it shares an organic model to deal with context-dependence. The building-block model and the organic model, and thus relativism and expressivism, are set apart with the aid of a particular test: only the building-block model is compatible with the idea that there might be analytically equivalent, and yet different, propositions.
Theoretical Aspects of the Equivalence Principle
Damour, Thibault
2012-01-01
We review several theoretical aspects of the Equivalence Principle (EP). We emphasize the unsatisfactory fact that the EP maintains the absolute character of the coupling constants of physics while General Relativity, and its generalizations (Kaluza-Klein,..., String Theory), suggest that all absolute structures should be replaced by dynamical entities. We discuss the EP-violation phenomenology of dilaton-like models, which is likely to be dominated by the linear superposition of two effects: a signal proportional to the nuclear Coulomb energy, related to the variation of the fine-structure constant, and a signal proportional to the surface nuclear binding energy, related to the variation of the light quark masses. We recall the various theoretical arguments (including a recently proposed anthropic argument) suggesting that the EP be violated at a small, but not unmeasurably small level. This motivates the need for improved tests of the EP. These tests are probing new territories in physics that are related t...
Nogawa, Tomoaki
2012-10-18
We examine the effectiveness of assuming an equal probability for states far from equilibrium. For this aim, we propose a method to construct a master equation for extensive variables describing nonstationary nonequilibrium dynamics. The key point of the method is the assumption that transient states are equivalent to the equilibrium state that has the same extensive variables, i.e., an equal probability holds for microscopic states in nonequilibrium. We demonstrate an application of this method to the critical relaxation of the two-dimensional Potts model by Monte Carlo simulations. While the one-variable description, which is adequate for equilibrium, yields relaxation dynamics that are very fast, the redundant two-variable description well reproduces the true dynamics quantitatively. These results suggest that some class of the nonequilibrium state can be described with a small extension of degrees of freedom, which may lead to an alternative way to understand nonequilibrium phenomena. © 2012 American Physical Society.
Vertical Equilibrium of Sheet Pile Walls with Emphasis on Toe Capacity and Plugging
DEFF Research Database (Denmark)
Iversen, Kirsten Malte; Augustesen, Anders Hust; Nielsen, Benjaminn Nordahl
at the pile toe to fulfil vertical equilibrium. The paper describes a case study of sheet pile walls in Aalborg Clay, and the amount of loads transferred as point loads at the pile toe for free and anchored walls is estimated. A parametric study is made for the free wall with regards to the height...... and the roughness of the wall. Due to limitations of the calculation method, the study of the anchored wall only includes variation of the roughness. For the case study, it is found that the vertical equilibrium is fulfilled for the considered free wall. An anchored wall needs a plug forming at the pile toe...
Patel, Sandeep; Brooks, Charles L
2005-10-22
We present a molecular-dynamics simulation study of the bulk and liquid-vapor interfacial properties of ethanol using a polarizable force field based on the fluctuating charge (FQ) formalism, as well as the nonpolarizable CHARMM22 force field. Both models are competitive with respect to the prediction of ambient liquid properties such as liquid density, enthalpy of vaporization, dielectric constant, and self-diffusion constants. The polarizable model predicts an average condensed-phase dipole moment of 2.2 D associated with an induced liquid-phase dipole moment of 0.6 D; though qualitatively in agreement with earlier nonadditive models as well as recent Car-Parinello calculations, the current FQ model underestimates the condensed-phase dipole moment. In terms of liquid structure, both models are in agreement with recent neutron-diffraction results of liquid ethanol structure, although the polarizable model predicts the hydroxyl-hydrogen-hydroxyl-hydrogen structure factor in closer agreement with the experimental data. In terms of interfacial properties, both models predict ambient surface tension to within 4% of the experimental value of 22.8 dyncm, while overestimating the surface excess entropy by almost a factor of 2. Both models display the characteristic preferential orientation of interfacial molecules. The polarizable model allows for a monotonic variation of the average molecular dipole moment from the bulk value to that of the vapor phase. Consequently, there is a dramatic difference in the surface potential predicted by the polarizable and nonpolarizable models. The polarizable model estimates a surface potential of -209+/-3 mV, while the nonpolarizable model yields a value of -944+/-10 mV. Finally, based on the vapor-liquid equilibrium simulation data from several temperatures, we estimate the critical properties of both models. As observed with other FQ models for associating fluids (such as water and methanol), and counter to what one would anticipate
The evaluation of the neutron dose equivalent in the two-bend maze.
Tóth, Á Á; Petrović, B; Jovančević, N; Krmar, M; Rutonjski, L; Čudić, O
2017-04-01
The purpose of this study was to explore the effect of the second bend of the maze, on the neutron dose equivalent, in the 15MV linear accelerator vault, with two bend maze. These two bends of the maze were covered by 32 points where the neutron dose equivalent was measured. There is one available method for estimation of the neutron dose equivalent at the entrance door of the two bend maze which was tested using the results of the measurements. The results of this study show that the neutron equivalent dose at the door of the two bend maze was reduced almost three orders of magnitude. The measured TVD in the first bend (closer to the inner maze entrance) is about 5m. The measured TVD result is close to the TVD values usually used in the proposed models for estimation of neutron dose equivalent at the entrance door of the single bend maze. The results also determined that the TVD in the second bend (next to the maze entrance door) is significantly lower than the TVD values found in the first maze bend. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
Cosmic curvature from de Sitter equilibrium cosmology.
Albrecht, Andreas
2011-10-07
I show that the de Sitter equilibrium cosmology generically predicts observable levels of curvature in the Universe today. The predicted value of the curvature, Ω(k), depends only on the ratio of the density of nonrelativistic matter to cosmological constant density ρ(m)(0)/ρ(Λ) and the value of the curvature from the initial bubble that starts the inflation, Ω(k)(B). The result is independent of the scale of inflation, the shape of the potential during inflation, and many other details of the cosmology. Future cosmological measurements of ρ(m)(0)/ρ(Λ) and Ω(k) will open up a window on the very beginning of our Universe and offer an opportunity to support or falsify the de Sitter equilibrium cosmology.
The general equilibrium theory as economic metatheory
Directory of Open Access Journals (Sweden)
MAURICIO MARTINELLI LUPERI
2015-06-01
Full Text Available Many economists show certain nonconformity relative to the excessive mathematical formalization of economics. This stems from dissatisfaction with the old debate about the lack of correspondence between mainstream theoretical models and reality. Although we do not propose to settle this debate here, this article seeks to associate the mismatch of mathematized models with the reality of the adoption of the hypothetical-deductive method as reproduced by general equilibrium. We begin by defining the main benefits of the mathematization of economics. Secondly, we address traditional criticism leveled against it. We then focus on more recent criticism from Gillies (2005 and Bresser-Pereira (2008. Finally, we attempt to associate the reproduction of the hypothetical-deductive method with a metatheoretical process triggered by Debreu's general equilibrium theory. In this respect, we appropriate the ideas of Weintraub (2002, Punzo (1991, and mainly Woo (1986 to support our hypothesis.
Phase Equilibrium Investigations of Planetary Materials
Grove, T. L.
2005-01-01
This grant provided funds to carry out phase equilibrium studies on the processes of chemical differentiation of the moon and the meteorite parent bodies, during their early evolutionary history. Several experimental studies examined processes that led to the formation of lunar ultramafic glasses. Phase equilibrium studies were carried out on selected low-Ti and high-Ti lunar ultramafic glass compositions to provide constraints on the depth range, temperature and processes of melt generation and/or assimilation. A second set of experiments examined the role of sulfide melts in core formation processes in the earth and terrestrial planets. The major results of each paper are discussed, and copies of the papers are attached as Appendix I.
Equilibrium-Based Nonhomogeneous Anisotropic Beam Element
DEFF Research Database (Denmark)
Krenk, Steen; Couturier, Philippe
2017-01-01
The stiffness matrix and the nodal forces associated with distributed loads are obtained for a nonhomogeneous anisotropic elastic beam element by the use of complementary energy. The element flexibility matrix is obtained by integrating the complementary-energy density corresponding to six beam...... equilibrium states, and then inverted and expanded to provide the element-stiffness matrix. Distributed element loads are represented via corresponding internal-force distributions in local equilibrium with the loads. The element formulation does not depend on assumed shape functions and can, in principle......, include any variation of cross-sectional properties and load variation, provided that these are integrated with sufficient accuracy in the process. The ability to represent variable cross-sectional properties, coupling from anisotropic materials, and distributed element loads is illustrated by numerical...
Instability of quantum equilibrium in Bohm's dynamics.
Colin, Samuel; Valentini, Antony
2014-11-08
We consider Bohm's second-order dynamics for arbitrary initial conditions in phase space. In principle, Bohm's dynamics allows for 'extended' non-equilibrium, with initial momenta not equal to the gradient of phase of the wave function (as well as initial positions whose distribution departs from the Born rule). We show that extended non-equilibrium does not relax in general and is in fact unstable. This is in sharp contrast with de Broglie's first-order dynamics, for which non-standard momenta are not allowed and which shows an efficient relaxation to the Born rule for positions. On this basis, we argue that, while de Broglie's dynamics is a tenable physical theory, Bohm's dynamics is not. In a world governed by Bohm's dynamics, there would be no reason to expect to see an effective quantum theory today (even approximately), in contradiction with observation.
On equilibrium charge distribution above dielectric surface
Directory of Open Access Journals (Sweden)
Yu.V. Slyusarenko
2009-01-01
Full Text Available The problem of the equilibrium state of the charged many-particle system above dielectric surface is formulated. We consider the case of the presence of the external attractive pressing field and the case of its absence. The equilibrium distributions of charges and the electric field, which is generated by these charges in the system in the case of ideally plane dielectric surface, are obtained. The solution of electrostatic equations of the system under consideration in case of small spatial heterogeneities caused by the dielectric surface, is also obtained. These spatial inhomogeneities can be caused both by the inhomogeneities of the surface and by the inhomogeneous charge distribution upon it. In particular, the case of the "wavy" spatially periodic surface is considered taking into account the possible presence of the surface charges.
Predicting wave-induced ripple equilibrium geometry
Robert Nelson, Timothy; Voulgaris, George; Traykovski, Peter
2013-06-01
A comprehensive database of existing (since 1954) field and laboratory measurements of ripple geometry is compiled and combined with newly collected field data to examine the performance of ripple equilibrium predictors. Reanalysis of this enlarged ripple geometry data set reveals that ripples formed from monochromatic waves scale differently than ripples formed from random waves for many existing ripple predictors. Our analysis indicates that ripple wavelengths from the two data sets collapse into a single scaling when the semiorbital excursion and sediment grain diameter are used as normalizing factors. Ripple steepness remains relatively constant for both regular and irregular wave conditions, and it only slightly increases for shorter ripple wavelengths. These findings allowed for the development of a new equilibrium ripple predictor suitable for application in a wide range of wave and sediment conditions.
Auditory Stimulus Equivalence and Non-Arbitrary Relations
National Research Council Canada - National Science Library
Stewart, Ian; Lavelle, Niamh
2013-01-01
This study extended previous research on stimulus equivalence with all auditory stimuli by using a methodology more similar to conventional match-to-sample training and testing for three 3-member equivalence relations...
Nanostructured energy devices equilibrium concepts and kinetics
Bisquert, Juan
2014-01-01
Due to the pressing needs of society, low cost materials for energy devices have experienced an outstanding development in recent times. In this highly multidisciplinary area, chemistry, material science, physics, and electrochemistry meet to develop new materials and devices that perform required energy conversion and storage processes with high efficiency, adequate capabilities for required applications, and low production cost. Nanostructured Energy Devices: Equilibrium Concepts and Kinetics introduces the main physicochemical principles that govern the operation of energy devices. It inclu
Structural Stability of Tokamak Equilibrium: Transport Barriers
Energy Technology Data Exchange (ETDEWEB)
Solano, E. R.
2001-07-01
A generalised theory of structural stability of differential equations is introduced and applied to the Grad-Shafranov equation. It is discussed how the formation and loss of transport barrier could be associated with the appearance/disappearance of equilibria. The equilibrium conjecture is presented: transport barriers are associated with locally diamagnetic regions in the plasma, and affected by the paramagnetism of the bootstrap current. (Author) 18 refs.
Ionization equilibrium of a magnetized quantum plasma
Energy Technology Data Exchange (ETDEWEB)
Steinberg, M.; Ortner, J.; Ebeling, W. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik
2001-07-01
The influence of a constant uniform magnetic field on the ionization equilibrium and the thermodynamic properties of a nondegenerate partially ionized hydrogen plasma is studied for weak and strong magnetic fields. A simple interpolation formula for an effective partition function is proposed, connecting the the low- and high-field results. Furthermore, a closed analytical approximation for the thermodynamic functions in the chemical picture and a Saha equation for weakly and strongly magnetized plasmas are presented. (orig.)
Ultracold atomic quantum gases far from equilibrium
Energy Technology Data Exchange (ETDEWEB)
Gasenzer, Thomas [Institut fuer Theoretische Physik, Ruprecht-Karls Universitaet Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany); Berges, Juergen [Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstrasse, 64289 Darmstadt (Germany); Schmidt, Michael G. [Institut fuer Theoretische Physik, Ruprecht-Karls Universitaet Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany); Seco, Marcos [Institut fuer Theoretische Physik, Ruprecht-Karls Universitaet Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany)
2007-03-15
We calculate the time evolution of a far-from-equilibrium initial state of a non-relativistic ultracold Bose gas in one spatial dimension. The non-perturbative approximation scheme is based on a systematic expansion of the two-particle irreducible effective action in powers of the inverse number of field components. This yields dynamic equations which contain direct scattering, memory and off-shell effects that are not captured in mean-field theory.
Ultracold atomic quantum gases far from equilibrium
Gasenzer, T.; Berges, J.; Schmidt, M G; Seco, M.
2006-01-01
We calculate the time evolution of a far-from-equilibrium initial state of a non-relativistic ultracold Bose gas in one spatial dimension. The non-perturbative approximation scheme is based on a systematic expansion of the two-particle irreducible effective action in powers of the inverse number of field components. This yields dynamic equations which contain direct scattering, memory and off-shell effects that are not captured in mean-field theory.
Ionization equilibrium of hot hydrogen plasma
Potekhin, A Yu
1996-01-01
The hydrogen plasma is studied at temperatures T ~ 10^4 - 10^6 K using the free energy minimization method. A simple analytic free energy model is proposed which is accurate at densities up to 1 g/cc and yields convergent internal partition function of atoms. The occupation probability formalism is modified for solving the ionization equilibrium problem. The ionization degree and equation of state are calculated and compared with the results of other models.
The equilibrium size distribution of rouleaux.
Perelson, A S; Wiegel, F.W.
1982-01-01
Rouleaux are formed by the aggregation of red blood cells in the presence of macromolecules that bridge the membranes of adherent erythrocytes. We compute the size and degree of branching of rouleaux for macroscopic systems in thermal equilibrium in the absence of fluid flow. Using techniques from statistical mechanics, analytical expressions are derived for (a) the average number of rouleaux consisting of n cells and having m branch points; (b) the average number of cells per rouleau; (c) th...
Energy Technology Data Exchange (ETDEWEB)
Araujo, Eduardo Eudes Nobrega de; Santos Junior, Jose Araujo dos; Amaral, Romilton dos Santos; Santos, Josineide Marques do Nascimento; Spacov, Isabel Cristina Guerra; Fernandez, Zahily Herrero, E-mail: eduardo.eudes@ufpe.br, E-mail: jaraujo@ufpe.br, E-mail: romilton@ufpe.br, E-mail: neideden@hotmail.com, E-mail: isabelspacov@gmail.com, E-mail: zahily1985@gmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear. Grupo de Radioecologia
2015-07-01
The earth's crust has in its composition the Naturally Occurring Radioactive Material (NORM) that may have increased concentration due to activities of exploration and extraction of environmental resources. The civil construction is an economic activity that requires the use of much of the natural resources, such as the raw material of brick works, like clays, mainly used for the production of bricks and tiles. These construction materials may contain high levels of natural radioactive elements, even with concentrations higher than the limits established, given that the levels vary according to the composition of rocks and soil, due to the geological formation and may result in increased exposure of humans to natural radioactive activities. In this context, the radioecological dosimetry is defined in terms of Radium Equivalent activity (Ra{sub eq}), that ensure radiometric conditions for the use of material derived from clays before its final application in housing construction, an initiative that ensures the radioecological safety of population. Thus, this study aimed to establish the calculation of Ra{sub eq} in the raw material of brick works located in Sao Jose do Sabugi city, state of Paraiba, in an area adjacent to the uranium deposits of Espinharas, to estimate the risks associated with primordial radionuclides attributed to TENORM activities (Technologically Enhanced Naturally Occurring Radioactive Materials) from the extraction and use of clay as a raw material in the manufacture of bricks and tiles. Analyses were performed by High Resolution Gamma Spectrometry, with HPGe-Be detector, assuming the state of secular radioactive equilibrium. The results ranged from 183.2 to 747.78 Bq/kg, with an average of 494.6 Bq/kg which exceeded the limit of 370 Bq/kg established by UNSCEAR for construction materials. Some samples obtained values exceeded by up the double this limit, suggesting control and radiometric certification for application of this material