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
thermodynamics of ion exchange equilibrium for some uni
African Journals Online (AJOL)
a
equilibrium constant K was calculated by taking into account the activity coefficient of ions both in solution as well as in the resin phase. For uni-univalent ion exchange reaction systems, the equilibrium constant K' were also calculated by considering mole fraction of ions in the resin phase. The K values calculated for ...
Thermodynamics of ion exchange equilibrium for some uni ...
African Journals Online (AJOL)
The study on thermodynamics of ion exchange equilibrium for uni-univalent Cl-/I-, Cl-/Br-, and uni-divalent Cl-/SO42-, Cl-/C2O42- reaction systems was carried out using ion exchange resin Indion FF-IP. The equilibrium constant K was calculated by taking into account the activity coefficient of ions both in solution as well as ...
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...
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...
Modeling Inflation Using a Non-Equilibrium Equation of Exchange
Chamberlain, Robert G.
2013-01-01
Inflation is a change in the prices of goods that takes place without changes in the actual values of those goods. The Equation of Exchange, formulated clearly in a seminal paper by Irving Fisher in 1911, establishes an equilibrium relationship between the price index P (also known as "inflation"), the economy's aggregate output Q (also known as "the real gross domestic product"), the amount of money available for spending M (also known as "the money supply"), and the rate at which money is reused V (also known as "the velocity of circulation of money"). This paper offers first a qualitative discussion of what can cause these factors to change and how those causes might be controlled, then develops a quantitative model of inflation based on a non-equilibrium version of the Equation of Exchange. Causal relationships are different from equations in that the effects of changes in the causal variables take time to play out-often significant amounts of time. In the model described here, wages track prices, but only after a distributed lag. Prices change whenever the money supply, aggregate output, or the velocity of circulation of money change, but only after a distributed lag. Similarly, the money supply depends on the supplies of domestic and foreign money, which depend on the monetary base and a variety of foreign transactions, respectively. The spreading of delays mitigates the shocks of sudden changes to important inputs, but the most important aspect of this model is that delays, which often have dramatic consequences in dynamic systems, are explicitly incorporated.macroeconomics, inflation, equation of exchange, non-equilibrium, Athena Project
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...
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.
Ion exchange equilibrium for some uni-univalent and uni-divalent ...
African Journals Online (AJOL)
The study on thermodynamics of ion exchange equilibrium for uni-univalent Cl-/I-, Cl-/Br-, and uni-divalent Cl-/SO42-, Cl-/C2O42- reaction systems was carried out using ion exchange resin Duolite A-102 D. The equilibrium constant K was calculated by taking into account the activity coefficient of ions both in solution as well ...
ion exchange equilibrium for some uni-univalent and uni-divalent ...
African Journals Online (AJOL)
a
equilibrium constant K was calculated by taking into account the activity coefficient of ions both in solution as well as in the resin phase. The K values calculated for uni-univalent and uni-divalent anion exchange reaction systems was observed to increase with rise in temperature, indicating the endothermic exchange ...
Tsirlin, A. M.
2017-09-01
The requirements with which a heat exchange system should comply in order that at certain values of the total contact surface and heat load the entropy production in it should be minimal have been determined. It has been shown that this system can serve as a standard for real systems of irreversible heat exchange. We have found the conditions for physical realizability of a heat exchange system in which heat exchange occurs by a law linear with respect to the temperature difference between contacting flows. Analogous conditions are given without deriving for the case of heat exchange by the Fourier law.
Study of lithium ion exchange by two synthetic zeolites: Kinetics and equilibrium.
Navarrete-Casas, R; Navarrete-Guijosa, A; Valenzuela-Calahorro, C; López-González, J D; García-Rodríguez, A
2007-02-15
We examined the exchange of univalent cations (Na+ and H+) retained on two commercially available synthetic zeolites with Li+ ions present in aqueous solutions in contact with the solids with a view to preparing effective controlled-release pharmaceutical forms. The studied zeolites were manufactured by Merck and featured channel diameters of 0.5 (Zeolite 5A, Ref. 1.05705.250, designated Z-05 in this work) and 1.0 nm (Zeolite 13X, Ref. 1.05703.250, designated Z-10 here). The XRD technique revealed that Z-05 possesses an LTA structure derived from that of sodalite and Z-10 a faujasite-type structure. Their exchange capacities were found to be 2.72 and 3.54 meq/g. The Z-Na + Li(+) / Z-Li + Na(+) and Z-H + Li(+) / Z-Li + H(+) ion-exchange processes were found to be reversible and their kinetic laws to obey the equation (-dC/dt) = k(a) x C(n) x (1-theta) - (k(d) x theta), with n = 1 for Z-10 and n = 2 for Z-05. Based on the equilibrium results, the overall processes involve one (with Z-05) or two single ion-exchange processes (with Z-10). In both cases, the equations that govern equilibrium are direct results of the kinetic laws. Thus, the first process-the one with only Z-05-involves the retention of Li+ cations at anionic sites on the outer surface of the solid and their access to the larger pores; the second process-which occurs with Z-10 only-involves the retention of lithium(I) cations within the zeolite channels. In both systems, the exchange with Li+ (from the aqueous solution) is easier than that with H+; this is consistent with our kinetic, equilibrium, and thermodynamic results.
Oka, Takashi; Aoki, Hideo
2010-01-01
Non-equilibrium phase transitions are studied theoretically for the two-dimensional Hubbard model subject to bias voltages from the electrodes coupled to the system. By combining the fluctuation exchange approximation with the Keldysh method for non-equilibrium, we have studied the properties of the non-equilibrium Fermi liquid phase and determined the phase diagram with transition to non-equilibrium magnetic and superconducting phases.
A study on equilibrium and kinetics of ion exchange of alkaline earth ...
Indian Academy of Sciences (India)
A study on equilibrium and kinetics of ion exchange of alkaline earth metals using an inorganic cation exchanger - zirconium titanium phosphate ... Further, various kinetic parameters like self-diffusion coefficient (0), energy of activation () and entropy of activation (*) have been evaluated under conditions favouring a ...
Equilibrium exchange rate assessment in Serbia using the IMF external sustainability approach
Directory of Open Access Journals (Sweden)
Pažun Brankica
2014-01-01
Full Text Available The exchange rate has always been a topical issue, particularly in the last two decades, at the time of strong world economy globalisation, as well as liberalization of international flows of goods, services and factors of production, which has resulted in stronger trade and financial integration. There has been a rise in the share of trade in world GDP. Growing developing countries contribute significantly to this growth, which is evident from the data that show increase of their share in world trade , as well as their importance in international capital flows. One of the most important concepts in open macroeconomics is the equilibrium real exchange rate - ERER. Deviations of the real exchange rate are considered to be the cause of the loss of competitiveness and economic slowdown, as well as possible currency crisis (overvaluation and undervaluation. Disadvantages of traditional concepts in exchange rate assessment which are very often reflected in unsuccessful empirical results, motivate experts to seek alternative models to assist in equilibrium exchange rate analysis. This paper aims to present one of three complementary methodologies used by the International Monetary Fund, for the equilibrium real exchange rate assessment in Serbia, as well as the deviation of the real exchange rate from its (estimated equilibrium, that is external sustainability approach.
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…
Directory of Open Access Journals (Sweden)
Yuming Cui
2013-09-01
Full Text Available The aim of this paper is to estimate the degree of RMB misalignment from its equilibrium exchange rate by applying the Behavioral Equilibrium Exchange Rate (BEER approach. We employ monthly data with reference to China's top 20 trading partners covering the period of 1997 to 2012. We find that the RMB was slightly overvalued before 2001 and significantly undervalued by up to 20 per cent in the end of 2006. There is evidence showing that the RMB approached to its equilibrium level from 2007 to 2008. However, the global financial crisis interrupted the trend of declining misalignment of RMB exchange rate. The RMB's total misalignment increased to around 25 per cent in the mid-2011 mainly because the RMB was re-pegged to the US dollar and some currencies of China's main trading partners depreciated during the period of crisis. More recently, the degree of RMB misalignment slightly declined since 2012 when the RMB proceeded to appreciate and China's ratio of current account surplus to GDP dropped considerably. Our findings prove that there is a trend of the RMB approaching to its equilibrium exchange rate since 2007 except for the period of crisis.
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.
Nikolaos Giannellis; Athanasios Papadopoulos
2006-01-01
This paper proposes an alternative way of testing FOREX efficiency for developing countries. The FOREX market will be efficient if fully reflects all available information. If this holds, the actual exchange rate will not deviate significantly from its equilibrium rate. Moreover, the spot rate should deviate from its equilibrium rate by only transitory components (i.e. it should follow a white noise process). This test is applied to three Central & Eastern European Countries – members of the ...
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.
Open quantum systems far from equilibrium
Schaller, Gernot
2014-01-01
This monograph provides graduate students and also professional researchers aiming to understand the dynamics of open quantum systems with a valuable and self-contained toolbox. Special focus is laid on the link between microscopic models and the resulting open-system dynamics. This includes how to derive the celebrated Lindblad master equation without applying the rotating wave approximation. As typical representatives for non-equilibrium configurations it treats systems coupled to multiple reservoirs (including the description of quantum transport), driven systems, and feedback-controlled quantum systems. Each method is illustrated with easy-to-follow examples from recent research. Exercises and short summaries at the end of every chapter enable the reader to approach the frontiers of current research quickly and make the book useful for quick reference.
Equilibrium Constant as Solution to the Open Chemical Systems
Zilbergleyt, B.
2008-01-01
According to contemporary views, equilibrium constant is relevant only to true thermodynamic equilibria in isolated systems with one chemical reaction. The paper presents a novel formula that ties-up equilibrium constant and chemical system composition at any state, isolated or open as well. Extending the logarithmic logistic map of the Discrete Thermodynamics of Chemical Equilibria, this formula maps the system population at isolated equilibrium into the population at any open equilibrium at...
Equilibrium data for cesium ion exchange of Hanford CC and NCAW tank waste
Energy Technology Data Exchange (ETDEWEB)
Bray, L.A.; Carson, K.J.; Elovich, R.J.; Kurath, D.E.
1996-04-01
Hanford alkaline waste storage-tank contents will be processed to remove the soluble salts. A major fraction of these solutions will require cesium recovery to produce a low-level waste (LLW). The technology for decontamination of high-level alkaline waste and sludge wash waters is being developed. At the request of Westinghouse Hanford Company (WHC), the Pacific Northwest Laboratory (PNL) has studied several ion exchange materials for the recovery of cesium from Hanford waste tanks. The WHC program was divided into tow main tasks, (1) to obtain equilibrium data for cesium ion exchange, and (2) to evaluate ion exchange column performance. The subject of this letter report is the measurement of batch distribution coefficients for several ion exchange media for a range of operating conditions for two types of waste; complexant concentrate (CC) and neutralized current acid waste (NCAW).
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.
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
Stochastic driven systems far from equilibrium
Kim, Kyung Hyuk
We study the dynamics and steady states of two systems far from equilibrium: a 1-D driven lattice gas and a driven Brownian particle with inertia. (1) We investigate the dynamical scaling behavior of a 1-D driven lattice gas model with two species of particles hopping in opposite directions. We confirm numerically that the dynamic exponent is equal to z = 1.5. We show analytically that a quasi-particle representation relates all phase points to a special phase line directly related to the single-species asymmetric simple exclusion process. Quasi-particle two-point correlations decay exponentially, and in such a manner that quasi-particles of opposite charge dynamically screen each other with a special balance. The balance encompasses all over the phase space. These results indicate that the model belongs to the Kardar-Parisi-Zhang (KPZ) universality class. (2) We investigate the non-equilibrium thermodynamics of a Brownian particle with inertia under feedback control of its inertia. We find such open systems can act as a molecular refrigerator due to an entropy pumping mechanism. We extend the fluctuation theorems to the refrigerator. The entropy pumping modifies both the Jarzynski equality and the fluctuation theorems. We discover that the entropy pumping has a dual role of work and heat. We also investigate the thermodynamics of the particle under a hydrodynamic interaction described by a Langevin equation with a multiplicative noise. The Stratonovich stochastic integration prescription involved in the definition of heat is shown to be the unique physical choice.
NaSi⇌CaAl exchange equilibrium between plagioclase and amphibole
Spear, Frank S.
1980-03-01
The exchange equilibrium between plagioclase and amphibole, 2 albite+tschermakite=2 anorthite+glaucophane, has been calibrated empirically using data from natural amphibolites. The partition coefficient, K D, for the exchange reaction is ( X an/ X ab)plag ·(Na, M4/Ca, M4)amph.. Partitioning is systematic between plagioclase and amphibole in suites collected from single exposures, but the solid solutions are highly non-ideal: values of In K D range from -3.0 at X an=0.30 to -1.0 at X an=0.90 in samples from a single roadcut. Changes in both K D and the topology of the ternary reciprocal exchange diagram occur with increasing metamorphic grade. Temperature dependence of In K D is moderate with Δ ¯H≃35 to 47 kcal at X an=0.25; pressure dependence is small with Δ ¯V≃ -0.24 cal/bar. Usefulness of this exchange equilibrium as a geothermometer is restricted by uncertainties in the calculation of the amphibole formula from a microprobe analysis, especially with regard to Na, M4 in amphibole, to approximately ±50 ° C.
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.
Amazon basin: a system in equilibrium.
Salati, E; Vose, P B
1984-07-13
Despite the very active deforestation of the last decade, the Amazon Basin is still primarily covered with trees and is a system in equilibrium. The Andes form a barrier at the western end of the basin and, coupled with the prevailing easterly winds, ensure an almost unique precipitation and water-recycling regime. On average 50 percent of the precipitation is recycled, and in some areas even more. The soils are poor. Most of the nitrogen and phosphorus is found in the soil, and the remaining nutrient elements are found in the standing biomass. There is some nutrient recycling and little loss from the intact ecosystem, and the small input of nutrients from precipitation maintains a small positive nutrient balance. Continued large-scale deforestation is likely to lead to increased erosion and water runoff with initial flooding in the lower Amazon, together with reduced evapotranspiration and ultimately reduced precipitation. Reduced precipitation in the Amazon could increase the tendency toward continentality and adversely affect climate and the present agriculture in south-central Brazil.
Equilibrium ion exchange studies of Ni2+ on homoionic forms of clinoptilolite
Directory of Open Access Journals (Sweden)
Joshua Gorimbo
2014-05-01
Full Text Available A natural zeolite (clinoptilolite that is mined in KwaZulu-Natal, South Africa, was evaluated for the removal of Ni2+ from wastewater. In particular, the effect of zeolite modification on Ni2+ removal from synthetic wastewater was investigated. The natural clinoptilolite was pretreated with 2 M metal chlorides for 24 h to yield near homoionic Na+, K+ and Ca2+ forms. A comparison of the isotherms for the Na+-Ni2+, K+-Ni2+, Ca2+-Ni2+ and natural-Ni2+ systems gave insight into how the displaced ion affects the selectivity of the clinoptilolite for Ni2+. The Na+, K+ and natural forms show highly selective convex isotherms whereas the Ca2+ form has a concave graph suggesting that the selectivity series is Ca2+> Ni2+> (Na+, K+, natural. Thermodynamic properties revealed that the Ni2+ sorption capacity increases as the values of the equilibrium constant and Gibbs free energy increase with increasing temperature from 298.15 K to 348.15 K. The enthalpy change was positive for all forms of clinoptilolite; values of 26.00 kJ/mol, 18.72 kJ/mol and 42.05 kJ/mol were obtained for exchange of Ni2+ into Na+, K+ and Ca2+ forms, respectively. The positive changes in enthalpy provide an indication that the sorption reaction is endothermic for Ni(II. The Gibbs free energy values were all negative except for Ca2+-exchanged clinoptilolite at 298.15 K and 308.15 K, for which the values were positive 3.10 kJ/mol and 0.53 kJ/mol, respectively. The entropy values for Ni2+ sorption were also positive; values of 0.12 kJ/mol.K, 0.08 kJ/mol.K and 0.14 kJ/mol.K were obtained for the Na+, K+ and Ca2+ forms, respectively. As expected, the enthalpy obtained from the Van’t Hoff plot is dependent not only on the metal ion being adsorbed, but also on the ion being displaced. Pretreatment of the zeolite enhances the removal efficiency provided that monovalent ions are used for the pretreatment. Thus clinoptilolite is an effective low-cost absorbent for the removal of Ni2+ from
Identifying apparent local stable isotope equilibrium in a complex non-equilibrium system.
He, Yuyang; Cao, Xiaobin; Wang, Jianwei; Bao, Huiming
2018-02-28
Although being out of equilibrium, biomolecules in organisms have the potential to approach isotope equilibrium locally because enzymatic reactions are intrinsically reversible. A rigorous approach that can describe isotope distribution among biomolecules and their apparent deviation from equilibrium state is lacking, however. Applying the concept of distance matrix in graph theory, we propose that apparent local isotope equilibrium among a subset of biomolecules can be assessed using an apparent fractionation difference (|Δα|) matrix, in which the differences between the observed isotope composition (δ') and the calculated equilibrium fractionation factor (1000lnβ) can be more rigorously evaluated than by using a previous approach for multiple biomolecules. We tested our |Δα| matrix approach by re-analyzing published data of different amino acids (AAs) in potato and in green alga. Our re-analysis shows that biosynthesis pathways could be the reason for an apparently close-to-equilibrium relationship inside AA families in potato leaves. Different biosynthesis/degradation pathways in tubers may have led to the observed isotope distribution difference between potato leaves and tubers. The analysis of data from green algae does not support the conclusion that AAs are further from equilibrium in glucose-cultured green algae than in the autotrophic ones. Application of the |Δα| matrix can help us to locate potential reversible reactions or reaction networks in a complex system such as a metabolic system. The same approach can be broadly applied to all complex systems that have multiple components, e.g. geochemical or atmospheric systems of early Earth or other planets. Copyright © 2017 John Wiley & Sons, Ltd.
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...
Topologically protected modes in non-equilibrium stochastic systems
Murugan, Arvind; Vaikuntanathan, Suriyanarayanan
2017-01-01
Non-equilibrium driving of biophysical processes is believed to enable their robust functioning despite the presence of thermal fluctuations and other sources of disorder. Such robust functions include sensory adaptation, enhanced enzymatic specificity and maintenance of coherent oscillations. Elucidating the relation between energy consumption and organization remains an important and open question in non-equilibrium statistical mechanics. Here we report that steady states of systems with non-equilibrium fluxes can support topologically protected boundary modes that resemble similar modes in electronic and mechanical systems. Akin to their electronic and mechanical counterparts, topological-protected boundary steady states in non-equilibrium systems are robust and are largely insensitive to local perturbations. We argue that our work provides a framework for how biophysical systems can use non-equilibrium driving to achieve robust function.
Energy Technology Data Exchange (ETDEWEB)
Wedler, F.C.; Hsuanyu, Y.; Kantrowitz, E.R.
1987-05-01
Isotope exchange kinetics at equilibrium (EIEK) have been used to probe the kinetic and regulatory mechanisms of native aspartate transcarbamoylase (ATCase) from E. coli at pH 7.0, 30/sup 0/. Substrate saturation patterns were most consistent with a preferred order random kinetic mechanism: C-P prior to L-Asp, C-Asp released before Pi, with the Asp in equilibrium C-Asp exchange rate 5X faster than C-P in equilibrium Pi. Computer simulations allow one to fit the EIEK experimental data and to arrive at the best set of kinetic constants for a given enzyme state. These approaches have been applied to modified ATCase. Bound CTP and ATP were observed, respectively, to inhibit and activate differentially Asp in equilibrium C-Asp, but not C-P in equilibrium Pi, indicating that these modifiers alter the association-dissociation rates of L-Asp and C-Asp but not of C-P or Pi. Low levels of PALA activated both exchange rates (due to shifting the T-R equilibrium), but higher (PALA) completely blocked both exchanges. The effects of a site-specific mutation of Tyr240 Phe have been similarly probed by EIEK methods. The Phe240 mutant enzyme exhibited kinetic properties markedly different from native ATCase: the data indicate that Phe240 ATCase is much closer to an R-state enzyme than is native enzyme.
Statistical fluctuations and correlations in hadronic equilibrium systems
Energy Technology Data Exchange (ETDEWEB)
Hauer, Michael
2010-06-17
This thesis is dedicated to the study of fluctuation and correlation observables of hadronic equilibrium systems. The statistical hadronization model of high energy physics, in its ideal, i.e. non-interacting, gas approximation is investigated in different ensemble formulations. The hypothesis of thermal and chemical equilibrium in high energy interaction is tested against qualitative and quantitative predictions. (orig.)
Equilibrium and shot noise in mesoscopic systems
Energy Technology Data Exchange (ETDEWEB)
Martin, T.
1994-10-01
Within the last decade, there has been a resurgence of interest in the study of noise in Mesoscopic devices, both experimentally and theoretically. Noise in solid state devices can have different origins: there is 1/f noise, which is believed to arise from fluctuations in the resistance of the sample due to the motion of impurities. On top of this contribution is a frequency independent component associated with the stochastic nature of electron transport, which will be the focus of this paper. If the sample considered is small enough that dephasing and inelastic effects can be neglected, equilibrium (thermal) and excess noise can be completely described in terms of the elastic scattering properties of the sample. As mentioned above, noise arises as a consequence of random processes governing the transport of electrons. Here, there are two sources of randomness: first, electrons incident on the sample occupy a given energy state with a probability given by the Fermi-Dirac distribution function. Secondly, electrons can be transmitted across the sample or reflected in the same reservoir where they came from with a probability given by the quantum mechanical transmission/reflection coefficients. Equilibrium noise refers to the case where no bias voltage is applied between the leads connected to the sample, where thermal agitation alone allows the electrons close to the Fermi level to tunnel through the sample. In general, equilibrium noise is related to the conductance of the sample via the Johnson-Nyquist formula. In the presence of a bias, in the classical regime, one expects to recover the full shot noise < {Delta}{sup 2}I >= 2I{Delta}{mu} as was observed a long time ago in vacuum diodes. In the Mesoscopic regime, however, excess noise is reduced below the shot noise level. The author introduces a more intuitive picture, where the current passing through the device is a superposition of pulses, or electron wave packets, which can be transmitted or reflected.
Directory of Open Access Journals (Sweden)
Viktor Shevchuk
2010-10-01
Full Text Available By means of VAR and 2SLS assessments in the article researches the influence of the RER deviations from the equilibrium signification received through the Hodrick-Prescott filter. The author proved that understated RER worsens the GDP dynamics and accelerates the inflation simultaneously restricting the export and import demand. The results obtained testify to the benefit of hryvnia exchange rate growth as a means of dynamic acceleration of the economic growth in the low-inflation environment. It’s appropriate to neutralize possible balance deterioration of the trade balance is with the use of nonprice factors like reduction of the budget deficit and limitation of the money stock offers.
The picture exchange communication system.
Bondy, A S; Frost, L A
1998-01-01
The Picture Exchange Communication System (PECS) was developed as a means to teach children with autism and related developmental disabilities a rapidly acquired, self-initiating, functional communication system. Its theoretical roots combine principles from applied behavior analysis and guidelines established within the field of alternative and augmentative communication. This approach has several potential advantages relative to imitation-based strategies (both vocal and gestural) and symbol selection strategies. The system begins with the exchange of simple icons but rapidly builds "sentence" structure. The system also emphasizes developing the request function prior to developing responding to simple questions and commenting. The development of requesting with a sentence structure also permits the rapid development of attributes more traditionally taught within a receptive mode. The relationship between the introduction of PECS and various other behavioral issues (i.e., social approach and behavior management) as well as its relationship to the codevelopment of speech are reviewed.
Thermodynamic length for far-from-equilibrium quantum systems.
Deffner, Sebastian; Lutz, Eric
2013-02-01
We consider a closed quantum system initially at thermal equilibrium and driven by arbitrary external parameters. We derive a lower bound on the entropy production which we express in terms of the Bures angle between the nonequilibrium and the corresponding equilibrium state of the system. The Bures angle is an angle between mixed quantum states and defines a thermodynamic length valid arbitrarily far from equilibrium. As an illustration, we treat the case of a time-dependent harmonic oscillator for which we obtain analytic expressions for generic driving protocols.
Energy Technology Data Exchange (ETDEWEB)
Coppola, C. M.; Longo, S. [Dipartimento di Chimica, Universita degli Studi di Bari, Via Orabona 4, I-70126 Bari (Italy); D' Introno, R. [Dipartimento di Fisica, Universita degli Studi di Bari, Via Amendola 173, I-70126 Bari (Italy); Galli, D. [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); Tennyson, J., E-mail: carla.coppola@chimica.uniba.it [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)
2012-03-01
Energy exchange processes play a crucial role in the early universe, affecting the thermal balance and the dynamical evolution of the primordial gas. In the present work we focus on the consequences of a non-thermal distribution of the level populations of H{sub 2}: first, we determine the excitation temperatures of vibrational transitions and the non-equilibrium heat transfer; second, we compare the modifications to chemical reaction rate coefficients with respect to the values obtained assuming local thermodynamic equilibrium; and third, we compute the spectral distortions to the cosmic background radiation generated by the formation of H{sub 2} in vibrationally excited levels. We conclude that non-equilibrium processes cannot be ignored in cosmological simulations of the evolution of baryons, although their observational signatures remain below current limits of detection. New fits to the equilibrium and non-equilibrium heat transfer functions are provided.
Balance Mass Flux and Velocity Across the Equilibrium Line in Ice Drainage Systems of Greenland
Zwally, H. Jay; Giovinetto, Mario B.; Koblinsky, Chester J. (Technical Monitor)
2001-01-01
Estimates of balance mass flux and the depth-averaged ice velocity through the cross-section aligned with the equilibrium line are produced for each of six drainage systems in Greenland. (The equilibrium line, which lies at approximately 1200 m elevation on the ice sheet, is the boundary between the area of net snow accumulation at higher elevations and the areas of net melting at lower elevations around the ice sheet.) Ice drainage divides and six major drainage systems are delineated using surface topography from ERS (European Remote Sensing) radar altimeter data. The net accumulation rate in the accumulation zone bounded by the equilibrium line is 399 Gt/yr and net ablation rate in the remaining area is 231 Gt/yr. (1 GigaTon of ice is 1090 kM(exp 3). The mean balance mass flux and depth-averaged ice velocity at the cross-section aligned with the modeled equilibrium line are 0.1011 Gt kM(exp -2)/yr and 0.111 km/yr, respectively, with little variation in these values from system to system. The ratio of the ice mass above the equilibrium line to the rate of mass output implies an effective exchange time of approximately 6000 years for total mass exchange. The range of exchange times, from a low of 3 ka in the SE drainage system to 14 ka in the NE, suggests a rank as to which regions of the ice sheet may respond more rapidly to climate fluctuations.
Gold Loading on Ion Exchange Resins in Non-Ammoniacal Resin-Solution Systems
Directory of Open Access Journals (Sweden)
Abrar Muslim
2010-12-01
Full Text Available The loading of gold using strong base anion exchange resin in non-ammoniac resin-solution (NARS systems has been studied. The loading of gold onto ion exchange resins is affected by polythionate concentration, and trithionate can be used as the baseline in the system. The results also show that resin capacity on gold loading increases due to the increase in the equilibrium thiosulfate concentration in the NARS system. Gold loading performances show the need of optimization the equilibrium concentrations of thiosulfate in the NARS system. Keywords: equilibrium, gold loading, resin capacity, thiosulfate, trithionate
Estimate of Equilibrium Real Exchange Rate and Misalignment of Chinese Yuan Vis-a-Vis US Dollar
Directory of Open Access Journals (Sweden)
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.
Data Exchange Inventory System (DEXI)
Social Security Administration — Enterprise tool used to identify data exchanges occurring between SSA and our trading partners. DEXI contains information on both incoming and outgoing exchanges and...
EPR of exchange coupled systems
Bencini, Alessandro
2012-01-01
From chemistry to solid state physics to biology, the applications of Electron Paramagnetic Resonance (EPR) are relevant to many areas. This unified treatment is based on the spin Hamiltonian approach and makes extensive use of irreducible tensor techniques to analyze systems in which two or more spins are magnetically coupled. This edition contains a new Introduction by coauthor Dante Gatteschi, a pioneer and scholar of molecular magnetism.The first two chapters review the foundations of exchange interactions, followed by examinations of the spectra of pairs and clusters, relaxation in oligon
Approach to thermal equilibrium of macroscopic quantum systems.
Goldstein, Sheldon; Lebowitz, Joel L; Mastrodonato, Christian; Tumulka, Roderich; Zanghi, Nino
2010-01-01
We consider an isolated macroscopic quantum system. Let H be a microcanonical "energy shell," i.e., a subspace of the system's Hilbert space spanned by the (finitely) many energy eigenstates with energies between E and E+deltaE . The thermal equilibrium macrostate at energy E corresponds to a subspace H(eq) of H such that dim H(eq)/dim H is close to 1. We say that a system with state vector psi is the element of H is in thermal equilibrium if psi is "close" to H(eq). We show that for "typical" Hamiltonians with given eigenvalues, all initial state vectors psi(0) evolve in such a way that psi(t) is in thermal equilibrium for most times t. This result is closely related to von Neumann's quantum ergodic theorem of 1929.
Fluctuations and large deviations in non-equilibrium systems
Indian Academy of Sciences (India)
For systems in contact with two reservoirs at different densities or with two thermostats at different temperatures, the large deviation function of the density gives a possible way of extending the notion of free energy to non-equilibrium systems. This large deviation function of the density can be calculated explicitly for ...
Fluctuations and large deviations in non-equilibrium systems
Indian Academy of Sciences (India)
systems. Keywords. Non-equilibrium systems; large deviations; current fluctuations. PACS Nos 02.50.-r; 05.40.-a; 05.70.Ln; 82.20.-w. 1. Introduction. The goal of this talk is to give a short review on results [1–8] obtained recently on the steady .... binary variable indicating whether site i is occupied or empty, the time evolution.
Energy Technology Data Exchange (ETDEWEB)
Kurath, D.E.; Bray, L.A.; Brooks, K.P.; Carlson, C.D.; Kim, A.Y.
1996-04-01
This report contains the results of a partial analysis and correlation of a large amount of equilibrium data obtained for cesium ion exchange. Data from testing of organic resins, a phenolic- carboxylic acid resin, and a resorcinol-formaldehyde resin with NCAW and CC waste simulants were assessed. The isotherms that were considered for correlating the data include the Langmuir, the Freundlich, and a combination of the two. These correlations are being developed to provide equations that can be used with models for assessing column behavior and provide correlations that will allow prediction of the equilibrium performance of the two resins with wastes of different compositions.
Data Exchange Inventory (DEXI) System
Social Security Administration — DEXI is an intranet application used by SSA users to track all incoming and outgoing data exchanges between SSA and our data exchange partners. Information such as...
Exchanger system for anhydrite pipeline
Energy Technology Data Exchange (ETDEWEB)
Penet, A.
1980-12-01
This paper deals with the problem of roadway behaviour affecting airways, bottom roads and top roads in advancing faces in the HBNPC area. The support work in these zones used to be undertaken manually and involved a lot of man hours. These operations are now mechanized in the form of pneumatic stowing with anhydrite. The latter is delivered by pipeline using compressed air. The 'exchanger' is a sort of branching system in the pipeline enabling the flow to be switched from the top end of the face to the bottom end and vice versa (diagram). The associated operations can be undertaken with ease. The effect the system has on costs will soon be known. (In French)
Rangel-Cárdenas, Angie L; Koper, Ger J M
2017-05-25
We hypothesize that the properties of proton-exchange membranes for fuel cell applications cannot be described unambiguously unless interface effects are taken into account. In order to prove this, we first develop a thermodynamically consistent description of the transport properties in the membranes, both for a homogeneous membrane and for a homogeneous membrane with two surface layers in contact with the electrodes or holder material. For each subsystem, homogeneous membrane, and the two surface layers, we limit ourselves to four parameters as the system as a whole is considered to be isothermal. We subsequently analyze the experimental results on some standard membranes that have appeared in the literature and analyze these using the two different descriptions. This analysis yields relatively well-defined values for the homogeneous membrane parameters and estimates for those of the surface layers and hence supports our hypothesis. As demonstrated, the method used here allows for a critical evaluation of the literature values. Moreover, it allows optimization of stacked transport systems such as proton-exchange membrane fuel cell units where interfacial layers, such as that between the catalyst and membrane, are taken into account systematically.
Directory of Open Access Journals (Sweden)
Angie L. Rangel-Cárdenas
2017-05-01
Full Text Available We hypothesize that the properties of proton-exchange membranes for fuel cell applications cannot be described unambiguously unless interface effects are taken into account. In order to prove this, we first develop a thermodynamically consistent description of the transport properties in the membranes, both for a homogeneous membrane and for a homogeneous membrane with two surface layers in contact with the electrodes or holder material. For each subsystem, homogeneous membrane, and the two surface layers, we limit ourselves to four parameters as the system as a whole is considered to be isothermal. We subsequently analyze the experimental results on some standard membranes that have appeared in the literature and analyze these using the two different descriptions. This analysis yields relatively well-defined values for the homogeneous membrane parameters and estimates for those of the surface layers and hence supports our hypothesis. As demonstrated, the method used here allows for a critical evaluation of the literature values. Moreover, it allows optimization of stacked transport systems such as proton-exchange membrane fuel cell units where interfacial layers, such as that between the catalyst and membrane, are taken into account systematically.
Quantum many-body systems out of equilibrium
Eisert, J.; Friesdorf, M.; Gogolin, Christian
2014-01-01
How do closed quantum many-body systems driven out of equilibrium eventually achieve equilibration? And how do these systems thermalize, given that they comprise so many degrees of freedom? Progress in answering these—and related— questions has accelerated in recent years—a trend that can be partially attributed to success with experiments performing quantum simulations using ultracold atoms and trapped ions. Here we provide an overview of this progress, specifically in studies pr...
Geometry and symmetry in non-equilibrium thermodynamic systems
Sonnino, Giorgio
2017-06-01
The ultimate aim of this series of works is to establish the closure equations, valid for thermodynamic systems out from the Onsager region, and to describe the geometry and symmetry in thermodynamic systems far from equilibrium. Geometry of a non-equilibrium thermodynamic system is constructed by taking into account the second law of thermodynamics and by imposing the validity of the Glansdorff-Prigogine Universal Criterion of Evolution. These two constraints allow introducing the metrics and the affine connection of the Space of the Thermodynamic Forces, respectively. The Lie group associated to the nonlinear Thermodynamic Coordinate Transformations (TCT) leaving invariant both the entropy production σ and the Glansdorff-Prigogine dissipative quantity P, is also described. The invariance under TCT leads to the formulation of the Thermodynamic Covariance Principle (TCP): The nonlinear closure equations, i.e. the flux-force relations, must be covariant under TCT. In other terms, the fundamental laws of thermodynamics should be manifestly covariant under transformations between the admissible thermodynamic forces (i.e. under TCT). The symmetry properties of a physical system are intimately related to the conservation laws characterizing the thermodynamic system. Noether's theorem gives a precise description of this relation. The macroscopic theory for closure relations, based on this geometrical description and subject to the TCP, is referred to as the Thermodynamic Field Theory (TFT). This theory ensures the validity of the fundamental theorems for systems far from equilibrium.
Modelling and simulation of phase equilibrium in dynamic systems
Directory of Open Access Journals (Sweden)
T. Dahl
1997-04-01
Full Text Available The article reports an investigation on how to efficiently describe phase equilibrium in dynamic systems, and how to solve the resulting equations numerically. An overview of possible solution strategies is given. Different thermodynamic models are briefly reviewed, and important algorithms like PT flash are described. A flash tank with a mixture of propane and propylene is simulated to illustrate some different solution strategies.
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.
Entropy exchange for infinite-dimensional systems.
Duan, Zhoubo; Hou, Jinchuan
2017-02-06
In this paper the entropy exchange for channels and states in infinite-dimensional systems are defined and studied. It is shown that, this entropy exchange depends only on the given channel and the state. An explicit expression of the entropy exchange in terms of the state and the channel is proposed. The generalized Klein's inequality, the subadditivity and the triangle inequality about the entropy including infinite entropy for the infinite-dimensional systems are established, and then, applied to compare the entropy exchange with the entropy change.
Doi, Hideo; Yasuoka, Kenji
2017-05-01
Confined systems exhibit interesting properties that are applied to the fields of lubrication, adhesion and nanotechnology. The replica exchange molecular simulation method was applied to calculate the phase equilibrium points of Lennard-Jones particles in a two-dimensional confined system. The liquid-solid phase equilibrium points and the solid structure with a dependency of the slit width were determined and the order parameter of the solid structure was analyzed. Such confined systems are shown to be favorable for manipulation of the phase equilibrium points.
Directory of Open Access Journals (Sweden)
Hideo Doi
2017-05-01
Full Text Available Confined systems exhibit interesting properties that are applied to the fields of lubrication, adhesion and nanotechnology. The replica exchange molecular simulation method was applied to calculate the phase equilibrium points of Lennard–Jones particles in a two-dimensional confined system. The liquid–solid phase equilibrium points and the solid structure with a dependency of the slit width were determined and the order parameter of the solid structure was analyzed. Such confined systems are shown to be favorable for manipulation of the phase equilibrium points.
Nichols, Michael A.; Waner, Mark J.
2010-01-01
An extension of the classic keto-enol tautomerization of beta-dicarbonyl compounds into a kinetic analysis of deuterium exchange is presented. It is shown that acetylacetone and ethyl acetoacetate undergo nearly complete deuterium exchange of the alpha-methylene carbon when dissolved in methanol-d[subscript 4]. The extent of deuteration may be…
The Equilibrium Compositions of Methanol Synthesis System by Cornstalk Syngas
Zhu, Ling-feng; Zhao, Qing-ling; Wang, Yang-yang; Chen, Jing; Zhang, Le; Zhang, Run-tao; Liu, Li-li; Zhang, Zhao-yue
2010-11-01
Methanol can be used as a promising alternative for conventional gasoline and Diesel fuel. It is necessary to decompose biomass such as cornstalks in order to produce methanol which is a raw material from agricultural residues. A promising route for processing cornstalks is firstly to gasify cornstalks with thermo-chemical method to prepare the syngas, which can be conducted under a down-flow fixed bed gasifier. The low-heat-value cornstalk syngas produced in this way needs purification and a variety of technical procedures such as deoxygenation, desulfurization, catalytic cracking of tar and hydrogenation. In this paper, the catalytic experiments of methanol synthesis with cornstalk syngas were carried out in a tubular-flow integral and isothermal reactor. The effect such as reaction temperature, pressure, catalyst types, catalyst particle size, syngas flow at entering end and composition of syngas was investigated. Moreover, the equilibrium constants (Kf1, Kf2, KP1, KP2), equilibrium compositions and the concentrations of each part of the equilibrium system for methanol synthesis were calculated by SHBWR state equation under given reaction pressure. The results provided basic data for the design of the industrial equipments in which catalyzed synthesis of methanol from cornstalk gases is operated.
Temperature and voltage measurement in quantum systems far from equilibrium
Shastry, Abhay; Stafford, Charles A.
2016-10-01
We show that a local measurement of temperature and voltage for a quantum system in steady state, arbitrarily far from equilibrium, with arbitrary interactions within the system, is unique when it exists. This is interpreted as a consequence of the second law of thermodynamics. We further derive a necessary and sufficient condition for the existence of a solution. In this regard, we find that a positive temperature solution exists whenever there is no net population inversion. However, when there is a net population inversion, we may characterize the system with a unique negative temperature. Voltage and temperature measurements are treated on an equal footing: They are simultaneously measured in a noninvasive manner, via a weakly coupled thermoelectric probe, defined by requiring vanishing charge and heat dissipation into the probe. Our results strongly suggest that a local temperature measurement without a simultaneous local voltage measurement, or vice versa, is a misleading characterization of the state of a nonequilibrium quantum electron system. These results provide a firm mathematical foundation for voltage and temperature measurements far from equilibrium.
Exchange fluctuation theorem for correlated quantum systems.
Jevtic, Sania; Rudolph, Terry; Jennings, David; Hirono, Yuji; Nakayama, Shojun; Murao, Mio
2015-10-01
We extend the exchange fluctuation theorem for energy exchange between thermal quantum systems beyond the assumption of molecular chaos, and describe the nonequilibrium exchange dynamics of correlated quantum states. The relation quantifies how the tendency for systems to equilibrate is modified in high-correlation environments. In addition, a more abstract approach leads us to a "correlation fluctuation theorem". Our results elucidate the role of measurement disturbance for such scenarios. We show a simple application by finding a semiclassical maximum work theorem in the presence of correlations. We also present a toy example of qubit-qudit heat exchange, and find that non-classical behaviour such as deterministic energy transfer and anomalous heat flow are reflected in our exchange fluctuation theorem.
Non-equilibrium dynamics of isolated quantum systems
Directory of Open Access Journals (Sweden)
Calabrese Pasquale
2015-01-01
Full Text Available The non-equilibrium dynamics of isolated quantum systems represent a theoretical and experimental challenge raising many fundamental questions with applications to different fields of modern physics. In these proceedings, we briefly review some of the recent findings on the subject, with particular emphasis to the existence of stationary expectation values of local observables and to their statistical mechanics description. It turns out that the appropriate statistical ensemble describing these asymptotic values depends on whether the Hamiltonian governing the time evolution is integrable or not.
A Variational Method in Out of Equilibrium Physical Systems
Pinheiro, Mario J
2012-01-01
A variational principle is further developed for out of equilibrium dynamical systems by using the concept of maximum entropy. With this new formulation it is obtained a set of two first-order differential equations, revealing the same formal symplectic structure shared by classical mechanics, fluid mechanics and thermodynamics. In particular, it is obtained an extended equation of motion for a rotating dynamical system, from where it emerges a kind of topological torsion current of the form $\\epsilon_{ijk} A_j \\omega_k$, with $A_j$ and $\\omega_k$ denoting components of the vector potential (gravitational or/and electromagnetic) and $\\omega$ is the angular velocity of the accelerated frame. In addition, it is derived a special form of Umov-Poynting's theorem for rotating gravito-electromagnetic systems, and obtained a general condition of equilibrium for a rotating plasma. The variational method is then applied to clarify the working mechanism of some particular devices, such as the Bennett pinch and vacuum a...
Development of the stock exchange information system
Directory of Open Access Journals (Sweden)
Miladinović Radojko
2006-01-01
Full Text Available The stock exchange represents the key institution for the development of capital market of any country. Thus the information system of every stock exchange must satisfy very strict international standards. The development of these systems is particularly difficult in countries in transition, due to intense economic and legal changes, lack of technical and financial resources, lack of experience and knowledge in the area of the capital market business, etc. Therefore the special software project management methodology for their realization must be clearly defined. In the development process of the Belgrade Stock Exchange (BSE information system a new software project management methodology for its realization has been defined, the application of which is illustrated through a series of different development stages of the Belgrade Stock Exchange information system. In order to make all the problems more comprehensive, only the continuous trading method is described, being the most frequently used trading method in the world.
Assessment, Cleanup and Redevelopment Exchange System (ACRES)
U.S. Environmental Protection Agency — The Assessment, Cleanup and Redevelopment Exchange System (ACRES) is an online database for Brownfields Grantees to electronically submit data directly to EPA.
Xie, H.; Ponton, C.; Kitchen, N.; Lloyd, M. K.; Lawson, M.; Formolo, M. J.; Eiler, J. M.
2016-12-01
Intramolecular isotope ordering can constrain temperatures of synthesis, mechanisms of formation, and/or source substrates of organic compounds. Here we explore site-specific hydrogen isotope variations of propane. Statistical thermodynamic models predict that at equilibrium methylene hydrogen (-CH2-) in propane will be 10's of per mil higher in D/H ratio than methyl hydrogen (-CH3) at geologically relevant temperatures, and that this difference is highly temperature dependent ( 0.5-1 ‰/°C). Chemical-kinetic controls on site-specific D/H in propane could constrain the mechanisms, conditions and extents of propane synthesis or destruction. We have developed a method for measuring the difference in D/H ratio between methylene and methyl hydrogen in propane by gas source mass spectrometry. The data were measured using the Thermo Fisher Double Focusing Sector high resolution mass spectrometer (DFS), and involve comparison of the D/H ratios of molecular ion (C3H8+) and the ethyl fragmental ion (C2H5+). We demonstrate the accuracy and precision of this method through analysis of D-labeled and independently analyzed propanes. In the exchange experiments, propane was heated (100-200 oC) either alone or in the presence of D-enriched water (δD=1,1419 ‰ SMOW), with or without one of several potentially catalytic substrates for hours to weeks. Propane was found to exchange hydrogen with water vigorously at 200 °C in the presence of metal catalysts. In the presence of Ni catalyst, methylene hydrogen exchanges 2.5 times faster than methyl hydrogen. Hydrogen exchange in the presence of Pd catalyst is more effective and can equilibrate hydrogen isotope distribution on propane on the order of 7 days. Isotopic exchange in the presence of natural materials have also been tested, but is only measurable in the methylene group at 200 °C. High catalytic activity of Pd permits attainment of a bracketed, time-invariant equilibrium state that we use to calibrate the site
Local temperature of an interacting quantum system far from equilibrium
Stafford, Charles A.
2016-06-01
A theory of local temperature measurement of an interacting quantum electron system far from equilibrium via a floating thermoelectric probe is developed. It is shown that the local temperature so defined is consistent with the zeroth, first, second, and third laws of thermodynamics, provided the probe-system coupling is weak and broadband. For non-broadband probes, the local temperature obeys the Clausius form of the second law and the third law exactly, but there are corrections to the zeroth and first laws that are higher order in the Sommerfeld expansion. The corrections to the zeroth and first laws are related, and can be interpreted in terms of the error of a nonideal temperature measurement. These results also hold for systems at negative absolute temperature.
Emergent hydrodynamics in integrable quantum systems out of equilibrium
Castro-Alvaredo, Olalla A; Yoshimura, Takato
2016-01-01
Understanding the general principles underlying strongly interacting quantum states out of equilibrium is one of the most important tasks of current theoretical physics. With experiments now able to access the intricate dynamics of many-body quantum systems, it is paramount to develop powerful and widely applicable methods that encode the emergent physics. Up to now, the strong dichotomy observed between integrable and non-integrable evolutions made an overarching theory difficult to build, especially for transport phenomena where space-time profiles show drastically different behaviours. We present a novel framework for studying transport in integrable systems: that of emergent hydrodynamics with infinitely-many conservation laws. This method bridges the conceptual gap between integrable and non-integrable quantum dynamics. We apply it to the description of energy transport between heat baths in interacting integrable systems. We provide for the first time a full description of the current-carrying non-equil...
Ion Exchange Resins Transforming Drug Delivery Systems.
Gupta, Shweta; Benien, Parul; Sahoo, P K
2010-07-01
Ion-exchange resins are light, porous, three-dimensional high molecular weight cross - linked matrix of hydrocarbon chains carrying positively or negatively charged sites that can attract an ion of opposite charge from the surrounding medium. There is stoichiometric exchange of mobile ions between the solid and the solution called as Ion-exchange which does not lead to any radical change in the properties and structure of the solid. Depending upon the type of Ionexchanged it can be either Cation-exchange or Anion-exchange. They are prepared in the form of granules, beads or sheets. As drug delivery systems they have received considerable attention after the 1950s due to their inertness, freedom from side effects, high drug loading capacity, ease of sterilization and the fact that their structure can be easily altered to achieve the desired drug release characteristics. Their use is revolutionizing all traditional delivery systems namely - oral, nasal, ophthalmic and parenteral. Ion- exchange resins have been used for the development of novel drug delivery systems (NDDSs), to modify the characteristics of the dosage form and various other biomedical applications. The present article deals with the varied applications of ion-exchange resins for taste making, as resinates (simple and microencapsulated or coated), Pennkinetic systems, in selective recovery of pharmaceuticals, in pH and ionic strength responsive systems, in gastro-retentive systems, in hollow fiber systems, as sigmoidal release systems, as site specific delivery systems and as inotophoretically assisted transdermal drug delivery systems. They also have an immense importance when used as disintegrants / superdisintegrants in formulation of orodispersible tablets, powder processing aids and in the dissolution and stabilization of drugs.
Interacting systems far from equilibrium quantum kinetic theory
Morawetz, Klaus
2018-01-01
This book presents an up-to-date formalism of non-equilibrium Green's functions covering different applications ranging from solid state physics, plasma physics, cold atoms in optical lattices up to relativistic transport and heavy ion collisions. Within the Green's function formalism, the basic sets of equations for these diverse systems are similar, and approximations developed in one field can be adapted to another field. The central object is the self-energy which includes all non-trivial aspects of the system dynamics. The focus is therefore on microscopic processes starting from elementary principles for classical gases and the complementary picture of a single quantum particle in a random potential. This provides an intuitive picture of the interaction of a particle with the medium formed by other particles, on which the Green's function is built on.
The equilibrium compositions of methanol synthesis system by cornstalk syngas
Energy Technology Data Exchange (ETDEWEB)
Zhu, L.F.; Du, L.; Zhao, Q.L.; Li, X.B.; Ming, H.T.; Wu, B. [North China Inst. of Water Conservancy and Hydroelectric Power, Zhengzhou (China). Dept. of Environmental Engineering
2008-07-01
Methanol is produced by decomposed biomass from agricultural residues. Various thermo-chemical gasification methods are used to process the cornstalks in order to produce syngas. The syngas is then purified using de-oxygenation, de-sulfurization, and catalytic cracking processes. This paper described a series of catalytic methanol synthesis experiments conducted in a tubular-flow integral and isothermal reactor. The aim of the study was to determine the density and reaction heat of preparing methanol with syngas. The experiments were conducted to examine reaction temperatures; pressure; catalyst types; catalyst particle size; syngas flow; and the composition of syngas. Equilibrium constants, compositions, and concentrations of the equilibrium system for methanol synthesis were calculated using SHBWR state equations under given reaction pressures. The study showed that under pressure, K{sub p1} is a function of temperature, pressure, and composition, while K{sub f1} is a function of temperature. Data obtained in the study will be used to design commercial synthesis equipment. 10 refs., 1 tab., 1 fig.
A study on equilibrium and kinetics of ion exchange of alkaline earth ...
Indian Academy of Sciences (India)
Unknown
meters. It was thought that if Ti4+ is incorporated in the matrix of zirconium phosphate or visa versa, the ion exchange properties of mixed zirconium–tita- nium phosphate could ... equivalent per gram (meq gm–1) is given by, av/w where a is the molarity of the .... (m2 s–1) (kJ mol–1) (kJ mol–1). Mg(II) H(I). 0⋅34 (6⋅33) 0⋅44 ...
HPLWR equilibrium core design with the KARATE code system
Energy Technology Data Exchange (ETDEWEB)
Maraczy, Cs.; Hegyi, Gy.; Hordosy, G.; Temesvari, E. [KFKI Atomic Energy Research Inst., Hungarian Academy of Sciences, Budapest (Hungary)
2011-07-01
The High Performance Light Water Reactor (HPLWR) is the European version of the various supercritical water cooled reactor proposals. The paper presents the activity of KFKI-AEKI in the field of neutronic core design within the framework of the 'HPLWR Phase 2' FP-6 and the Hungarian 'NUKENERG' projects. As the coolant density along the axial direction shows remarkable change, coupled neutronic- thermohydraulic calculations are essential which take into account the heating of moderator in the special water rods of the assemblies. A parametrized diffusion cross section library was prepared for the HPLWR assembly with the MULTICELL neutronic transport code. The parametrized cross sections are used by the KARATE program system, which was verified for supercritical conditions by comparative Monte Carlo calculations. To design the HPLWR equilibrium core preliminary loadings were assessed, which contain insulated assemblies with Gd burnable absorbers. The fuel assemblies have radial and axial enrichment zoning to reduce hot spots. (author)
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.
Darnell, K.; Flemings, P. B.; DiCarlo, D. A.
2016-12-01
Guest molecule exchange is a new and promising methane hydrate production technique in which methane gas is produced by injection of another gas without requiring depressurization or thermal stimulation. The technique is generally associated with injection of carbon dioxide, but injection of nitrogen and carbon dioxide mixtures are the most efficient and economical. However, thermodynamic behavior of injection mixtures is poorly understood, and it is unclear how nitrogen affects the exchange process. Here, we describe thermodynamic stability of hydrate systems that contain water, methane, carbon dioxide, and nitrogen. We present a series of ternary and quaternary phase diagrams and show the impact nitrogen has on hydrate stability. Our results demonstrate that nitrogen can either stabilize hydrate, de-stabilize hydrate, or produce three-phase equilibrium (gas, water, and hydrate) depending on its relative abundance. At low abundance nitrogen forms hydrate and directly contributes to the exchange process. At high abundance nitrogen de-stabilizes hydrate akin to traditional hydrate inhibitors, such as salt, alcohol, or mono-ethylene glycol. We show how the dual properties of nitrogen lead to three-phase equilibrium and how three-phase equilibrium may explain much of the behavior observed in methane production from nitrogen-rich injections. We apply our analysis to laboratory experiments and the methane hydrate field test on the northern Alaskan slope at Ignik Sikumi. These results can be extended to analyze dynamic evolution of mixed hydrate systems.
Parametrizing coarse grained models for molecular systems at equilibrium
Kalligiannaki, Evangelia
2016-10-18
Hierarchical coarse graining of atomistic molecular systems at equilibrium has been an intensive research topic over the last few decades. In this work we (a) review theoretical and numerical aspects of different parametrization methods (structural-based, force matching and relative entropy) to derive the effective interaction potential between coarse-grained particles. All methods approximate the many body potential of mean force; resulting, however, in different optimization problems. (b) We also use a reformulation of the force matching method by introducing a generalized force matching condition for the local mean force in the sense that allows the approximation of the potential of mean force under both linear and non-linear coarse graining mappings (E. Kalligiannaki, et al., J. Chem. Phys. 2015). We apply and compare these methods to: (a) a benchmark system of two isolated methane molecules; (b) methane liquid; (c) water; and (d) an alkane fluid. Differences between the effective interactions, derived from the various methods, are found that depend on the actual system under study. The results further reveal the relation of the various methods and the sensitivities that may arise in the implementation of numerical methods used in each case.
Emergent Hydrodynamics in Integrable Quantum Systems Out of Equilibrium
Castro-Alvaredo, Olalla A.; Doyon, Benjamin; Yoshimura, Takato
2016-10-01
Understanding the general principles underlying strongly interacting quantum states out of equilibrium is one of the most important tasks of current theoretical physics. With experiments accessing the intricate dynamics of many-body quantum systems, it is paramount to develop powerful methods that encode the emergent physics. Up to now, the strong dichotomy observed between integrable and nonintegrable evolutions made an overarching theory difficult to build, especially for transport phenomena where space-time profiles are drastically different. We present a novel framework for studying transport in integrable systems: hydrodynamics with infinitely many conservation laws. This bridges the conceptual gap between integrable and nonintegrable quantum dynamics, and gives powerful tools for accurate studies of space-time profiles. We apply it to the description of energy transport between heat baths, and provide a full description of the current-carrying nonequilibrium steady state and the transition regions in a family of models including the Lieb-Liniger model of interacting Bose gases, realized in experiments.
Emergent Hydrodynamics in Integrable Quantum Systems Out of Equilibrium
Directory of Open Access Journals (Sweden)
Olalla A. Castro-Alvaredo
2016-12-01
Full Text Available Understanding the general principles underlying strongly interacting quantum states out of equilibrium is one of the most important tasks of current theoretical physics. With experiments accessing the intricate dynamics of many-body quantum systems, it is paramount to develop powerful methods that encode the emergent physics. Up to now, the strong dichotomy observed between integrable and nonintegrable evolutions made an overarching theory difficult to build, especially for transport phenomena where space-time profiles are drastically different. We present a novel framework for studying transport in integrable systems: hydrodynamics with infinitely many conservation laws. This bridges the conceptual gap between integrable and nonintegrable quantum dynamics, and gives powerful tools for accurate studies of space-time profiles. We apply it to the description of energy transport between heat baths, and provide a full description of the current-carrying nonequilibrium steady state and the transition regions in a family of models including the Lieb-Liniger model of interacting Bose gases, realized in experiments.
PANNEMAN, HJ; BEENACKERS, AACM
The liquid-phase hydration of cyclohexene, a pseudo-first-order reversible reaction catalyzed by a strong acid ion-exchange resin, was investigated in solvent mixtures of water and sulfolane. Macroporous Amberlite XE 307 was used because of its superior catalytic activity. Chemical equilibrium
Kowalczyk, T H; Horn, P J; Pan, W H; Phillips, N F
1996-05-28
Polyphosphate glucokinase [EC 2.7.1.63] catalyzes the phosphorylation of glucose using either inorganic polyphosphate [poly(P)] or ATP as the phosphoryl donor. Both activities purified from Propionibacterium shermanii are the functional properties of a single enzyme with separate binding sites for the two phosphoryl donor substrates. The enzyme was found to utilize poly(P) much more efficiently than it does ATP, with a kcat/Kpoly(P) to kcat/KATP ratio of 2800. The catalytic constant for poly(P) is about 2-fold higher than for ATP. Other nucleotides like GTP and dATP also served as substrates with good efficiencies. The ATP-dependent reaction was analyzed using steady-state kinetics and isotopic exchange kinetics at chemical equilibrium. Intersecting initial velocity patterns for both glucose and ATP indicate sequential addition of substrates. Product inhibition studies resulted in two competitive and two noncompetitive patterns, which is characteristic of a Theorell-Chance mechanism or a random mechanism with two dead-end complexes. Results of isotope exchange experiments, however, rule out a Theorell-Chance mechanism, as well as a truly random mechanism. They are not consistent with a partially random mechanism (although a kinetically compulsory order of substrate binding is not excluded), where glucose is preferentially bound to free enzyme before ATP, and ADP is preferentially released as the first product, followed by glucose 6-phosphate. Dead-end inhibition analysis confirms this order of substrate binding. Competitive inhibition of ADP vs ATP is explained as resulting primarily from binding as a dead-end inhibitor (E.Glc.ADP) and not as a product. Another weaker abortive complex, E.ATP.G6P, is also formed. The chemical transformation or the release of ADP is the rate-limiting step in ATP utilization.
Equilibrium ion exchange studies of Ni2+ on homoionic forms of clinoptilolite
Joshua Gorimbo; Blessing Taenzana; Kutemba Kapanji; Linda L. Jewell
2014-01-01
A natural zeolite (clinoptilolite) that is mined in KwaZulu-Natal, South Africa, was evaluated for the removal of Ni2+ from wastewater. In particular, the effect of zeolite modification on Ni2+ removal from synthetic wastewater was investigated. The natural clinoptilolite was pretreated with 2 M metal chlorides for 24 h to yield near homoionic Na+, K+ and Ca2+ forms. A comparison of the isotherms for the Na+-Ni2+, K+-Ni2+, Ca2+-Ni2+ and natural-Ni2+ systems gave insight into how the displaced...
Carbon nanotube heat-exchange systems
Hendricks, Terry Joseph; Heben, Michael J.
2008-11-11
A carbon nanotube heat-exchange system (10) and method for producing the same. One embodiment of the carbon nanotube heat-exchange system (10) comprises a microchannel structure (24) having an inlet end (30) and an outlet end (32), the inlet end (30) providing a cooling fluid into the microchannel structure (24) and the outlet end (32) discharging the cooling fluid from the microchannel structure (24). At least one flow path (28) is defined in the microchannel structure (24), fluidically connecting the inlet end (30) to the outlet end (32) of the microchannel structure (24). A carbon nanotube structure (26) is provided in thermal contact with the microchannel structure (24), the carbon nanotube structure (26) receiving heat from the cooling fluid in the microchannel structure (24) and dissipating the heat into an external medium (19).
Heat Exchanger for Motor Vehicle Cooling System
Thuliez, Jean-Luc; Chevroulet, Tristan; Stoll, Daniel
1997-01-01
Heat exchanger for a motor vehicle cooling system including a sleeve-like meter hermetically mounted on, and surrounding, a hollow tubular chassis meter of the vehicle. The sleeve is provided with inlets and outlets communicating with the space between the sleeve and the chassis meter and vehicle coolant flows through the inlet and outlet. Air, flowing over the outside surface of the sleeve and the inside surface of the chassis meter, cools the vehicle coolant. SMH - MCC Smart, car concepts (...
40 CFR 63.104 - Heat exchange system requirements.
2010-07-01
... heat exchange system or at locations where the cooling water enters and exits each heat exchanger or any combination of heat exchangers. (i) For samples taken at the entrance and exit of recirculating... manufacturing process units. (iii) For samples taken at the entrance and exit of each heat exchanger or any...
Non-equilibrium reversible dynamics of work production in four-spin system in a magnetic field
Directory of Open Access Journals (Sweden)
E.A. Ivanchenko
2011-06-01
Full Text Available A closed system of the equations for the local Bloch vectors and spin correlation functions is obtained by decomplexification of the Liouville-von Neumann equation for 4 magnetic particles with the exchange interaction that takes place in an arbitrary time-dependent external magnetic field. The analytical and numerical analysis of the quantum thermodynamic variables is carried out depending on separable mixed initial state and the magnetic field modulation. Under unitary evolution, non-equilibrium reversible dynamics of power production in the finite environment is investigated.
Direct transition from a stable equilibrium to quasiperiodicity in non-smooth systems
DEFF Research Database (Denmark)
Zhusubaliyev, Z.T.; Mosekilde, Erik
2008-01-01
regions in phase space. When this happens, one can observe a number of different bifurcation scenarios. One scenario is the continuous transformation of the stable equilibrium into a stable period-1 cycle. Another is the transformation of the stable equilibrium into an unstable period-1 cycle with complex......The purpose of this Letter is to show how a border-collision bifurcation in a piecewise-smooth dynamical system can produce a direct transition from a stable equilibrium point to a two-dimensional invariant torus. Considering a system of nonautonomous differential equations describing the behavior...... of a power electronic DC/DC converter, we first determine the chart of dynamical modes and show that there is a region of parameter space in which the system has a single stable equilibrium point. Under variation of the parameters, this equilibrium may collide with a discontinuity boundary between two smooth...
Students' Understanding of Equilibrium and Stability: The Case of Dynamic Systems
Canu, Michaël; de Hosson, Cécile; Duque, Mauricio
2016-01-01
Engineering students in control courses have been observed to lack an understanding of equilibrium and stability, both of which are crucial concepts in this discipline. The introduction of these concepts is generally based on the study of classical examples from Newtonian mechanics supplemented with a control system. Equilibrium and stability are…
Non-equilibrium statistical physics with application to disordered systems
Cáceres, Manuel Osvaldo
2017-01-01
This textbook is the result of the enhancement of several courses on non-equilibrium statistics, stochastic processes, stochastic differential equations, anomalous diffusion and disorder. The target audience includes students of physics, mathematics, biology, chemistry, and engineering at undergraduate and graduate level with a grasp of the basic elements of mathematics and physics of the fourth year of a typical undergraduate course. The little-known physical and mathematical concepts are described in sections and specific exercises throughout the text, as well as in appendices. Physical-mathematical motivation is the main driving force for the development of this text. It presents the academic topics of probability theory and stochastic processes as well as new educational aspects in the presentation of non-equilibrium statistical theory and stochastic differential equations.. In particular it discusses the problem of irreversibility in that context and the dynamics of Fokker-Planck. An introduction on fluc...
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.
Spinor order parameter and equilibrium states of spin s = 1 Bose systems
Glushchenko, A. V.; Kovalevsky, M. Yu.
2017-09-01
The problem of classification of degenerate equilibrium states in spin s = 1 systems with the phase and magnetic symmetries simultaneously broken is considered. An assumption about the residual symmetry of degenerate equilibrium states and the transformation properties of the spinor order-parameter operator under transformations generated by additive integrals of motion yields equations that classify its equilibrium values. The anisotropic structure of the equilibrium values of the order parameter is presented in terms of the parameters of the residual symmetry generator. Based on the model with a separated condensate, the structure of the densities of the magnetic additive integrals of motion in the equilibrium state is revealed. A comparison is made with the results of existing studies on superfluid spin s = 1 systems.
Modelling non-equilibrium thermodynamic systems from the speed-gradient principle.
Khantuleva, Tatiana A; Shalymov, Dmitry S
2017-03-06
The application of the speed-gradient (SG) principle to the non-equilibrium distribution systems far away from thermodynamic equilibrium is investigated. The options for applying the SG principle to describe the non-equilibrium transport processes in real-world environments are discussed. Investigation of a non-equilibrium system's evolution at different scale levels via the SG principle allows for a fresh look at the thermodynamics problems associated with the behaviour of the system entropy. Generalized dynamic equations for finite and infinite number of constraints are proposed. It is shown that the stationary solution to the equations, resulting from the SG principle, entirely coincides with the locally equilibrium distribution function obtained by Zubarev. A new approach to describe time evolution of systems far from equilibrium is proposed based on application of the SG principle at the intermediate scale level of the system's internal structure. The problem of the high-rate shear flow of viscous fluid near the rigid plane plate is discussed. It is shown that the SG principle allows closed mathematical models of non-equilibrium processes to be constructed.This article is part of the themed issue 'Horizons of cybernetical physics'. © 2017 The Author(s).
Plasma exchange in progressive systemic sclerosis
Directory of Open Access Journals (Sweden)
Mohammad Bagher Owlia
2015-10-01
Full Text Available Systemic sclerosis (SSc is an autoimmune systemic disease of unknown etiology. Present treatment modalities have limited impact on clinical/ laboratory outcomes. For the first time in our center, we used plasma exchange (PEx in a rather young woman with recent onset but progressive SSc. She is a 39-year-old woman with a recent history of skin stiffness, Raynaud’s phenomenon, nail fold capillary changes and newly diagnosis of SSc presented to us due to worsening her clinical symptoms even after initiation of routine remedies such as low dose oral prednisolone, Ca-channel blockers, azathioprine and pentoxyfylline. After obtaining written consent, interdisciplinary discussion with experts in this field and agreement we started a series of plasma exchange with FFP replacement for her. A dramatic clinical response was observed in respect to Raynaud’s phenomenon, skin stiffness, tendon rub after three sessions of PEx. Her modified Rodnan skin score (MRSS dropped from 36 (before commencement of therapy to 28 in day 4 and 18 in day 20 after 15 sessions of PEx. In conclusion PEx could significantly modify the course of SSc as observed in our case study. Elimination of culprit immune mediators/cytokines/autoantibodies could be the possible mechanism of action of PEx.
Kazdal, Timur J.; Lang, Sebastian; Kühl, Frank; Hampe, Manfred J.
2014-03-01
The fuel cell technology is a key element for the hydrogen energy economy and therefore crucial for sustainable development. High temperature proton exchange membrane (HT-PEM) fuel cells (FC) can be operated with reformate gas and thus represent an important bridging technology for the energy transition to a renewable energy based system. HT-PEM FCs based on phosphoric acid (PA) are still subject to intense research, investigating the electrolyte behaviour. By enhancing state of the art 2D FEM simulations of FCs with the vapour liquid equilibrium of water-phosphoric acid and evaporation kinetics, a model was created in which the local concentration of PA can be calculated. Knowledge of the concentration field yields the basis for calculating the locally varying ionic conductivity and other physical properties. By describing the volume expansion behaviour of PA it was possible to predict the catalyst particle deactivation due to the swelling of PA. The in situ concentration predicted by the simulation ranges from 96 to 111 wt%. The model was validated using measured data of a single cell design for different temperatures and pressures. By varying the PA content flooding of the simulated fuel cell could be observed and was linked to humidification effects.
Trapped ion system for sympathetic cooling and non-equilibrium dynamics
Doret, Charlie; Jubin, Sierra; Stevenson, Sarah
2017-04-01
Atomic systems are superbly suited to the study of non-equilibrium dynamics. These systems' exquisite isolation from environmental perturbations leads to long relaxation times that enable exploration of far-from-equilibrium phenomena. We present progress towards trapping chains of multiple co-trapped calcium isotopes geared towards measuring thermal equilibration and sympathetic cooling rates. We also discuss plans for future experiments in non-equilibrium statistical mechanics, including exploration of the quantum-to-classical crossover between ballistic transport and diffusive, Fourier's Law conduction. This work is supported by Cottrell College Science Award from the Research Corporation for Science Advancement and by Williams College.
Studies on the formulation of thermodynamics and stochastic theory for systems far from equilibrium
Energy Technology Data Exchange (ETDEWEB)
Ross, J. [Stanford Univ., CA (United States)
1995-12-31
We have been working for some time on the formulation of thermodynamics and the theory of fluctuations in systems far from equilibrium and progress in several aspects of that development are reported here.
Valeriani, C.; Allen, R.J.; Morelli, M.J.; Frenkel, D.; Wolde, P.R. ten
2007-01-01
We present a method for computing stationary distributions for activated processes in equilibrium and nonequilibrium systems using forward flux sampling. In this method, the stationary distributions are obtained directly from the rate constant calculations for the forward and backward
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.
Relaxation to equilibrium of the expectation values in macroscopic quantum systems.
Monnai, Takaaki
2011-07-01
A quantum mechanical explanation of the relaxation to equilibrium is shown for macroscopic systems for nonintegrable cases and numerically verified. The macroscopic system is initially in an equilibrium state, subsequently externally perturbed during a finite time, and then isolated for a sufficiently long time. We show a quantitative explanation that the initial microcanonical state typically reaches a state whose expectation values are well approximated by the average over another microcanonical ensemble.
Thermal Propulsion Capture System Heat Exchanger Design
Richard, Evan M.
2016-01-01
One of the biggest challenges of manned spaceflight beyond low earth orbit and the moon is harmful radiation that astronauts would be exposed to on their long journey to Mars and further destinations. Using nuclear energy has the potential to be a more effective means of propulsion compared to traditional chemical engines (higher specific impulse). An upper stage nuclear engine would allow astronauts to reach their destination faster and more fuel efficiently. Testing these engines poses engineering challenges due to the need to totally capture the engine exhaust. The Thermal Propulsion Capture System is a concept for cost effectively and safely testing Nuclear Thermal Engines. Nominally, hydrogen exhausted from the engine is not radioactive, but is treated as such in case of fuel element failure. The Thermal Propulsion Capture System involves injecting liquid oxygen to convert the hydrogen exhaust into steam. The steam is then cooled and condensed into liquid water to allow for storage. The Thermal Propulsion Capture System concept for ground testing of a nuclear powered engine involves capturing the engine exhaust to be cooled and condensed before being stored. The hydrogen exhaust is injected with liquid oxygen and burned to form steam. That steam must be cooled to saturation temperatures before being condensed into liquid water. A crossflow heat exchanger using water as a working fluid will be designed to accomplish this goal. Design a cross flow heat exchanger for the Thermal Propulsion Capture System testing which: Eliminates the need for water injection cooling, Cools steam from 5800 F to saturation temperature, and Is efficient and minimizes water requirement.
Linking Equilibrium and Nonequilibrium Dynamics in Glass-Forming Systems
DEFF Research Database (Denmark)
Mauro, John C.; Guo, Xiaoju; Smedskjær, Morten Mattrup
Understanding nonequilibrium glassy dynamics is of great scientific and technological importance. However, prediction of the temperature, thermal history, and composition dependence of nonequilibrium viscosity is challenging due to the noncrystalline and nonergodic nature of the glassy state. Here......, we show that the nonequilibrium glassy dynamics are intimately connected with the equilibrium liquid dynamics. This is accomplished by deriving a new functional form for the thermal history dependence of nonequilibrium viscosity, which is validated against experimental measurements of industrial...... silicate glasses and computed viscosities for selenium over a wide range of conditions. Since the temperature and composition dependence of liquid viscosity can be predicted using temperature-dependent constraint theory, our work also opens the possibility to improve understanding of the physics...
Energy Technology Data Exchange (ETDEWEB)
Glavatskiy, K. S. [School of Chemical Engineering, The University of Queensland, St. Lucia QLD 4072 (Australia)
2015-10-28
Validity of local equilibrium has been questioned for non-equilibrium systems which are characterized by delayed response. In particular, for systems with non-zero thermodynamic inertia, the assumption of local equilibrium leads to negative values of the entropy production, which is in contradiction with the second law of thermodynamics. In this paper, we address this question by suggesting a variational formulation of irreversible evolution of a system with non-zero thermodynamic inertia. We introduce the Lagrangian, which depends on the properties of the normal and the so-called “mirror-image” systems. We show that the standard evolution equations, in particular, the Maxwell-Cattaneo-Vernotte equation, can be derived from the variational procedure without going beyond the assumption of local equilibrium. We also argue that the second law of thermodynamics in non-equilibrium should be understood as a consequence of the variational procedure and the property of local equilibrium. For systems with instantaneous response this leads to the standard requirement of the local instantaneous entropy production being always positive. However, if a system is characterized by delayed response, the formulation of the second law of thermodynamics should be altered. In particular, the quantity, which is always positive, is not the instantaneous entropy production, but the entropy production averaged over a proper time interval.
Glavatskiy, K S
2015-10-28
Validity of local equilibrium has been questioned for non-equilibrium systems which are characterized by delayed response. In particular, for systems with non-zero thermodynamic inertia, the assumption of local equilibrium leads to negative values of the entropy production, which is in contradiction with the second law of thermodynamics. In this paper, we address this question by suggesting a variational formulation of irreversible evolution of a system with non-zero thermodynamic inertia. We introduce the Lagrangian, which depends on the properties of the normal and the so-called "mirror-image" systems. We show that the standard evolution equations, in particular, the Maxwell-Cattaneo-Vernotte equation, can be derived from the variational procedure without going beyond the assumption of local equilibrium. We also argue that the second law of thermodynamics in non-equilibrium should be understood as a consequence of the variational procedure and the property of local equilibrium. For systems with instantaneous response this leads to the standard requirement of the local instantaneous entropy production being always positive. However, if a system is characterized by delayed response, the formulation of the second law of thermodynamics should be altered. In particular, the quantity, which is always positive, is not the instantaneous entropy production, but the entropy production averaged over a proper time interval.
Thermodynamics and stability of non-equilibrium steady states in open systems
Bulíček, Miroslav; Málek, Josef; Průša, Vít
2017-01-01
Thermodynamical arguments are known to be useful in the construction of physically motivated Lyapunov functionals for nonlinear stability analysis of spatially homogeneous equilibrium steady states in thermodynamically isolated systems. Unfortunately, the limitation to thermodynamically isolated systems is essential, and standard arguments are not applicable even for some very simple thermodynamically open systems. On the other hand, the nonlinear stability of thermodynamically open systems i...
RiverHeath: Neighborhood Loop Geothermal Exchange System
Energy Technology Data Exchange (ETDEWEB)
Geall, Mark [RiverHeath LLC, Appleton, WI (United States)
2016-07-11
The goal of the RiverHeath project is to develop a geothermal exchange system at lower capital infrastructure cost than current geothermal exchange systems. The RiverHeath system features an innovative design that incorporates use of the adjacent river through river-based heat exchange plates. The flowing water provides a tremendous amount of heat transfer. As a result, the installation cost of this geothermal exchange system is lower than more traditional vertical bore systems. Many urban areas are located along rivers and other waterways. RiverHeath will serve as a template for other projects adjacent to the water.
Equilibrium configurations of a cable drogue system towed in a helical motion
Cohen, Y.; Manor, H.
The dynamical equilibrium configuration of a system consisting of a drogue attached to a towed flexible cable is examined for the particular case depicted by a helical vertical descent. The motion equations, together with boundary conditions, were solved numerically after nondimensional treatment, and a region was found where results are of multivalued nature. Different cable configurations in dynamic equilibrium conditions were presented; the influence of constrained factors such as angular velocity, radius of towpoint and vertical rate of descent are discussed.
Time scales in the approach to equilibrium of macroscopic quantum systems.
Goldstein, Sheldon; Hara, Takashi; Tasaki, Hal
2013-10-04
We prove two theorems concerning the time evolution in general isolated quantum systems. The theorems are relevant to the issue of the time scale in the approach to equilibrium. The first theorem shows that there can be pathological situations in which the relaxation takes an extraordinarily long time, while the second theorem shows that one can always choose an equilibrium subspace, the relaxation to which requires only a short time for any initial state.
Data Exchange Management Information System (DEMIS)
Social Security Administration — DEMIS combines a database (Operational Data Store - ODS) of data exchange-related Management Information (MI) with the agency's querying and reporting utility, the...
Magnetic stability in exchange-spring and exchange bias systems after multiple switching cycles.
Energy Technology Data Exchange (ETDEWEB)
Jiang, J. S.; Inomata, A.; You, C.-Y.; Pearson, J. E.; Bader, S. D.
2001-06-01
We have studied the magnetic stability in exchange bias and exchange spring systems prepared via epitaxial sputter deposition. The two interfacial exchange coupled systems, Fe/Cr(211) double superlattices consisting of a ferromagnetic and an antiferromagnetic Fe/Cr superlattice that are exchange coupled through a Cr spacer, and Sin-Co/Fe exchange-spring bilayer structures with ferromagnetically coupled hard Sin-Co layer and soft Fe layer, were epitaxially grown on suitably prepared Cr buffer layers to give rise to different microstructure and magnetic anisotropy. The magnetic stability was investigated using the magneto-optic Kerr effect during repeated reversal of the soft layer magnetization by field cycling up to 10{sup 7} times. For uniaxial Fe/Cr exchange biased double superlattices and exchange spring bilayers with uniaxial Sin-Co, small but rapid initial decay in the exchange bias field HE and in the remanent magnetization is observed. However, the exchange spring bilayers with biaxial and random in-plane anisotropy in the Sin-Co layer shows gradual decay in H{sub E} and without large reduction of the magnetization. The different decay behaviors are attributed to the different microstructure and spin configuration of the pinning layers.
On the instability of equilibrium of a mechanical system with nonconservative forces
Directory of Open Access Journals (Sweden)
Vesković Miroslav
2004-01-01
Full Text Available In this paper the stability of equilibrium of nonholonomic systems, on which dissipative and nonconservative positional forces act, is considered. We have proved the theorems on the instability of equilibrium under the assumptions that: the kinetic energy, the Rayleigh’s dissipation function and the positional forces are infinitely differentiable functions; the projection of the positional force component which represents the first nontrivial form of Maclaurin’s series of that positional force to the plane, which is normal to the vectors of nonholonomic constraints in the equilibrium position, is central and repulsive (with its centre of action in the equilibrium position. The suggested theorems are generalization of the results from [V.V. Kozlov, Prikl. Math. Mekh. (PMM, T58, V5, (1994, 31-36] and [M.M. Veskovic, Theoretical and Applied Mechanics, 24, (1998, 139-154]. The result obtained is analogous to the result from [D.R. Merkin, Introduction to theory of the stability of motion, Nauka, Moscow (1987], which refers to the impossibility of equilibrium stabilization in a holonomic conservative system by dissipative and nonconservative positional forces in case when the potential energy in the equilibrium position has the maximum. The proving technique will be similar to that used in the paper [V.V. Kozlov, Prikl. Math. Mekh. (PMM, T58, V5, (1994, 31-36]. .
Linear response theory and optimal control for a molecular system under non-equilibrium conditions
Wang, Han; Hartmann, Carsten; Schütte, Christof
2013-12-01
In this paper, we propose a straightforward generalisation of the linear response theory on a finite time-horizon to systems in non-equilibrium that are subject to external forcing. We briefly revisit the standard linear response result for equilibrium systems, where we consider Langevin dynamics as a special case, and then give an alternative derivation using a change-of-measure argument that does not rely on any stationarity or reversibility assumption. This procedure easily enables us to calculate the second-order correction to the linear response formula (which may or may not be useful in practice). Furthermore, we outline how the novel non-equilibrium linear response formula can be used to compute optimal controls of molecular systems for cases in which one wants to steer the system to maximise a certain target expectation value. We illustrate our approach with simple numerical examples.
Scaling approach to quantum non-equilibrium dynamics of many-body systems
Energy Technology Data Exchange (ETDEWEB)
Gritsev, Vladimir; Barmettler, Peter [Physics Department, University of Fribourg, Chemin du Musee 3, 1700 Fribourg (Switzerland); Demler, Eugene, E-mail: vladimir.gritsev@unifr.c [Lyman Laboratory of Physics, Physics Department, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States)
2010-11-15
Understanding the non-equilibrium quantum dynamics of many-body systems is one of the most challenging problems in modern theoretical physics. While numerous approximate and exact solutions exist for systems in equilibrium, examples of non-equilibrium dynamics of many-body systems that allow reliable theoretical analysis are few and far between. In this paper, we discuss a broad class of time-dependent interacting systems subject to external linear and parabolic potentials, for which the many-body Schroedinger equation can be solved using a scaling transformation. We demonstrate that scaling solutions exist for both local and non-local interactions, and derive appropriate self-consistency equations. We apply this approach to several specific experimentally relevant examples of interacting bosons in one and two dimensions. As an intriguing result, we find that weakly and strongly interacting Bose gases expanding from a parabolic trap can exhibit very similar dynamics.
USER EQUILIBRIUM AND SYSTEM OPTIMUM TRAFFIC ASSIGNMENTS; ISTANBUL ROAD NETWORK EXAMPLE
Directory of Open Access Journals (Sweden)
Banihan GÜNAY
1996-03-01
Full Text Available The concept of road networks and traffic flow equilibrium conditions are briefly reviewed and discussed. In order to see whether some benefits for the society (e.g. whole network by employing a System Optimum assignment approach can be achieved or not, an assessment study was carried out on the Ystanbul road network using the actual data gathered. As a result of the system optimising simulation, queuing times on the Bosphorus Bridge dropped by 12% and speed of an average car increased by 16%, compared to the results produced by the User Equilibrium assignment. Besides, the total system journey time was also reduced by about 4%.
Equilibrium states of generic quantum systems subject to periodic driving.
Lazarides, Achilleas; Das, Arnab; Moessner, Roderich
2014-07-01
When a closed quantum system is driven periodically with period T, it approaches a periodic state synchronized with the drive in which any local observable measured stroboscopically approaches a steady value. For integrable systems, the resulting behavior is captured by a periodic version of a generalized Gibbs ensemble. By contrast, here we show that for generic nonintegrable interacting systems, local observables become independent of the initial state entirely. Essentially, this happens because Floquet eigenstates of the driven system at quasienergy ω(α) consist of a mixture of the exponentially many eigenstates of the undriven Hamiltonian, which are thus drawn from the entire extensive undriven spectrum. This is a form of equilibration which depends only on the Hilbert space of the undriven system and not on any details of its Hamiltonian.
Liquid–liquid equilibrium in the lithium–lanthanum system
Energy Technology Data Exchange (ETDEWEB)
Khairulin, Rashid A., E-mail: kra@itp.nsc.ru [Institute of Thermophysics, Siberian Branch of the Russian Academy of Sciences, Lavrentyev Avenue 1, 630090 Novosibirsk (Russian Federation); Belozerova, Anastasiya A. [Institute of Metallurgy, Ural Division of the Russian Academy of Sciences, Amundsen Street 101, 620016 Ekaterinburg (Russian Federation); Abdullaev, Rasul N. [Novosibirsk State University, Pirogov Street 2, 630090 Novosibirsk (Russian Federation); Stankus, Sergei V. [Institute of Thermophysics, Siberian Branch of the Russian Academy of Sciences, Lavrentyev Avenue 1, 630090 Novosibirsk (Russian Federation)
2016-08-20
Highlights: Liquid–liquid equilibria in the Li–La system are studied experimentally. The study is conducted by a gamma-ray attenuation technique. The phase diagram of the Li–La system is refined. - Abstract: The boundaries of the liquid–liquid immiscibility region on the phase diagram of the Li–La system have been determined by the gamma-ray attenuation technique. At the monotectic temperature (1118 K), the miscibility gap ranges from 0.25 to 92.9 at.% La. As the temperature increases, the solubility of the liquid metals in each other rises slightly.
Development of solid-gas equilibrium propulsion system for small spacecraft
Chujo, Toshihiro; Mori, Osamu; Kubo, Yuki
2017-11-01
A phase equilibrium propulsion system is a kind of cold-gas jet in which the phase equilibrium state of the fuel is maintained in a tank and its vapor is ejected when a valve is opened. One such example is a gas-liquid equilibrium propulsion system that uses liquefied gas as fuel. This system was mounted on the IKAROS solar sail and has been demonstrated in orbit. The system has a higher storage efficiency and a lighter configuration than a high-pressure cold-gas jet because the vapor pressure is lower, and is suitable for small spacecraft. However, the system requires a gas-liquid separation device in order to avoid leakage of the liquid, which makes the system complex. As another example of a phase equilibrium propulsion system, we introduce a solid-gas equilibrium propulsion system, which uses a sublimable substance as fuel and ejects its vapor. This system has an even lower vapor pressure and does not require such a separation device, instead requiring only a filter to keep the solid inside the tank. Moreover, the system is much simpler and lighter, making it more suitable for small spacecraft, especially CubeSat-class spacecraft, and the low thrust of the system allows spacecraft motion to be controlled precisely. In addition, the thrust level can be controlled by controlling the temperature of the fuel, which changes the vapor pressure. The present paper introduces the concept of the proposed system, and describes ejection experiments and its evaluation. The basic function of the proposed system is demonstrated in order to verify its usefulness.
Entropy production in a fluid-solid system far from thermodynamic equilibrium.
Chung, Bong Jae; Ortega, Blas; Vaidya, Ashwin
2017-11-24
The terminal orientation of a rigid body in a moving fluid is an example of a dissipative system, out of thermodynamic equilibrium and therefore a perfect testing ground for the validity of the maximum entropy production principle (MaxEP). Thus far, dynamical equations alone have been employed in studying the equilibrium states in fluid-solid interactions, but these are far too complex and become analytically intractable when inertial effects come into play. At that stage, our only recourse is to rely on numerical techniques which can be computationally expensive. In our past work, we have shown that the MaxEP is a reliable tool to help predict orientational equilibrium states of highly symmetric bodies such as cylinders, spheroids and toroidal bodies. The MaxEP correctly helps choose the stable equilibrium in these cases when the system is slightly out of thermodynamic equilibrium. In the current paper, we expand our analysis to examine i) bodies with fewer symmetries than previously reported, for instance, a half-ellipse and ii) when the system is far from thermodynamic equilibrium. Using two-dimensional numerical studies at Reynolds numbers ranging between 0 and 14, we examine the validity of the MaxEP. Our analysis of flow past a half-ellipse shows that overall the MaxEP is a good predictor of the equilibrium states but, in the special case of the half-ellipse with aspect ratio much greater than unity, the MaxEP is replaced by the Min-MaxEP, at higher Reynolds numbers when inertial effects come into play. Experiments in sedimentation tanks and with hinged bodies in a flow tank confirm these calculations.
Hoving, H; Lolkema, Juke S.; Robillard, George T.
1981-01-01
The phosphorylation of enzyme I from the Escherichia coli phosphoenolpyruvate-dependent phosphotransferase system was studied by means of isotope exchange between phosphoenolpyruvate and pyruvate. Experiments monitoring 1H-2H exchange showed that enzyme I phosphorylation is accompanied by the
Intelligent transportation system (ITS) international research exchange.
2014-01-01
ITS applications address surface transportation challenges in safety, mobility, and : sustainability that are similar in cause and impact worldwide. International ITS : exchange allows cooperating nations to benefit from each others pre-competitiv...
Chemical oceanography of the Arabian Sea: Part II - Equilibrium of inorganic nitrogen system
Digital Repository Service at National Institute of Oceanography (India)
Naik, S.; SenGupta, R.
The concept pE, expressed as a dimensionless quantity to study the redox potential of a system at equilibrium, is applied to study the chemistry of the system NO-_{3}-NO-_{2}NH+_{4} in the northern Arabian Sea. Values...
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.
Directory of Open Access Journals (Sweden)
Karthikeyan Rajagopal
2017-01-01
Full Text Available This paper introduces a fractional order memristor no equilibrium (FOMNE chaotic system and investigates its adaptive sliding mode synchronization. Firstly the dynamic properties of the integer order memristor no equilibrium system are analyzed. The fractional order memristor no equilibrium system is then derived from the integer order model. Lyapunov exponents and bifurcation with fractional order are investigated. An adaptive sliding mode control algorithm is derived to globally synchronize the identical fractional order memristor systems and genetically optimized fractional order PID controllers are designed and used to synchronize the FOMNE systems. Finally the fractional order memristor no equilibrium system is realized using FPGA.
Numerical computation of bifurcations in large equilibrium systems in MATLAB.
Bindel, David; Friedman, Mark; Govaerts, Willy; Hughes, Jeremy; Kuznetsov, Yuri
2014-01-01
The Continuation of Invariant Subspaces (CIS) algorithm produces a smoothly-varying basis for an invariant subspace R(s) of a parameter-dependent matrix A(s). We have incorporated the CIS algorithm into Cl_matcont, a Matlab package for the study of dynamical systems and their bifurcations. Using
Response and correlation functions of nonlinear systems in equilibrium states
Xu, Lubo; Wang, Lei
2017-11-01
In this paper, we study systematically a serial of correlation functions in some one-dimensional nonlinear lattices. Due to the energy conservation law, they are implicitly interdependent. Various transport coefficients are thus also connected. In the studies of the autocorrelations of local energy density and of local heat current, a general relation between diverging heat conduction and super heat diffusion has been proposed recently. We clarify that such a relation is valid only in systems without temperature pressure. In those with temperature pressure, a constant but nontrivial term appears. This term explains a previously observed fact that heat diffusion in such systems is always ballistic but heat conduction can diverge very slowly. Such a result not only disproves the existence of any general relation between diverging heat conduction and super heat diffusion, but it also breaks the long-term presumption that ballistic heat conduction and diffusion always coexist.
Non-equilibrium water flow in multimodal soil porous system
Kodesova, R.; Nikodem, A.; Jirku, V.
2009-04-01
Soil hydraulic properties of various horizons of Haplic Luvisol were studied under the laboratory and field conditions. Multistep outflow experiments were performed in the laboratory, and tension disk and Guelph permeameter tests were carried out in the field. The dual-permeability flow model in HYDRUS-1D and HYDRUS-2D were used to estimate the soil hydraulic parameters of matrix and macropore domains from the laboratory and field transient flow data via numerical inversion. First, the laboratory experimental data were analyzed to obtain soil hydraulic properties of the one-dimensional (small column) dual-permeability system. Parameters obtained for the matrix domains were then used to analyze field transient flow data of both permeameters tests to estimate parameters of macropore domains in the radially symmetric dual-permeability system. Results showed impact of various pore fractions (gravitational and large capillary pores) and multimodality of soil porous system, which were previously documented by Kodesova et al. (2008) in the micromorphological images, on preferential flow occurrence in structured soils. Acknowledgement: Authors acknowledge the financial support of the Grant Agency of the Czech Republic grant No. 526/08/0434, and the Ministry of Education, Youth and Sports grant No. MSM 6046070901.
Equilibrium spin current induced by spin-orbital interaction in a quantum dot system
Energy Technology Data Exchange (ETDEWEB)
Liang Feng [Department of Physics, Southeast University, Nanjing 211189 (China)], E-mail: lf_125s@sohu.com; Shen Yaoguo; Yang Yonghong [Department of Physics, Southeast University, Nanjing 211189 (China)
2008-06-16
We report a theoretical study of the equilibrium spin current flowing in a quantum dot system. Two electrodes are the two-dimensional electron gas with Rashba or Dresselhaus spin-orbital interaction. By using the Keldysh Green's function technique, we demonstrated that a nonzero spin current can flow in the system without bias. At the weak coupling between electrodes and the quantum dot, the spin current is approximately proportional to the cross product of two average pseudo-magnetizations in two electrodes, which agrees with the result of the linear response theory; whereas at the opposite case, the strong coupling between the quantum dot and electrodes can lead to a non-sinusoidal behavior of the equilibrium spin current. These behaviors of the equilibrium spin current are similar to the Josephson current.
Beyond the second law entropy production and non-equilibrium systems
Lineweaver, Charles; Niven, Robert; Regenauer-Lieb, Klaus
2014-01-01
The Second Law, a cornerstone of thermodynamics, governs the average direction of dissipative, non-equilibrium processes. But it says nothing about their actual rates or the probability of fluctuations about the average. This interdisciplinary book, written and peer-reviewed by international experts, presents recent advances in the search for new non-equilibrium principles beyond the Second Law, and their applications to a wide range of systems across physics, chemistry and biology. Beyond The Second Law brings together traditionally isolated areas of non-equilibrium research and highlights potentially fruitful connections between them, with entropy production playing the unifying role. Key theoretical concepts include the Maximum Entropy Production principle, the Fluctuation Theorem, and the Maximum Entropy method of statistical inference. Applications of these principles are illustrated in such diverse fields as climatology, cosmology, crystal growth morphology, Earth system science, environmental physics, ...
An equilibrium for frustrated quantum spin systems in the stochastic state selection method
Energy Technology Data Exchange (ETDEWEB)
Munehisa, Tomo; Munehisa, Yasuko [Faculty of Engineering, University of Yamanashi, Kofu 400-8511 (Japan)
2007-05-16
We develop a new method to calculate eigenvalues in frustrated quantum spin models. It is based on the stochastic state selection (SSS) method, which is an unconventional Monte Carlo technique that we have investigated in recent years. We observe that a kind of equilibrium is realized under some conditions when we repeatedly operate a Hamiltonian and a random choice operator, which is defined by stochastic variables in the SSS method, to a trial state. In this equilibrium, which we call the SSS equilibrium, we can evaluate the lowest eigenvalue of the Hamiltonian using the statistical average of the normalization factor of the generated state. The SSS equilibrium itself has already been observed in unfrustrated models. Our study in this paper shows that we can also see the equilibrium in frustrated models, with some restriction on values of a parameter introduced in the SSS method. As a concrete example, we employ the spin-1/2 frustrated J{sub 1}-J{sub 2} Heisenberg model on the square lattice. We present numerical results on the 20-, 32-, and 36-site systems, which demonstrate that statistical averages of the normalization factors reproduce the known exact eigenvalue to good precision. Finally, we apply the method to the 40-site system. Then we obtain the value of the lowest energy eigenvalue with an error of less than 0.2%.
Non-equilibrium phase transitions in a driven-dissipative system of interacting bosons
Young, Jeremy T.; Foss-Feig, Michael; Gorshkov, Alexey V.; Maghrebi, Mohammad F.
2017-04-01
Atomic, molecular, and optical systems provide unique opportunities to study simple models of driven-dissipative many-body quantum systems. Typically, one is interested in the resultant steady state, but the non-equilibrium nature of the physics involved presents several problems in understanding its behavior theoretically. Recently, it has been shown that in many of these models, it is possible to map the steady-state phase transitions onto classical equilibrium phase transitions. In the language of Keldysh field theory, this relation typically only becomes apparent after integrating out massive fields near the critical point, leaving behind a single massless field undergoing near-equilibrium dynamics. In this talk, we study a driven-dissipative XXZ bosonic model and discover critical points at which two fields become gapless. Each critical point separates three different possible phases: a uniform phase, an anti-ferromagnetic phase, and a limit cycle phase. Furthermore, a description in terms of an equilibrium phase transition does not seem possible, so the associated phase transitions appear to be inherently non-equilibrium.
New quasi-steady-state and partial-equilibrium methods for integrating chemically reacting systems
Mott, David Ray
1999-11-01
We present new quasi-steady-state (QSS) and partial- equilibrium (PE) methods for integrating systems of ordinary differential equations (ODEs) that arise from chemical reactions. These methods were developed for use in process-split reacting-flow simulations. The new QSS integrator is a second-order predictor- corrector method that is A-stable for linear equations. The method is accurate regardless of the timescales of the individual ODEs in the system and works well for problems typical of hydrocarbon combustion. The method has very low start-up costs, making it ideal for process- split reacting-flow simulations which require the solution of an initial-value problem in each computational cell in the flowfield for every global timestep. For problems of extreme stiffness, PE tools can be used in combination with the QSS integrator. PE methods remove the fastest reactions in the mechanism from the kinetic integration when their effects can be calculated using algebraic equilibrium constraints. Conservation constraints are used to write an ODE for the reaction's progress variable. The solution of this equation provides a new method for identifying reactions in equilibrium. A systematic method for finding a set of conserved scalars for an arbitrary group of reactions is presented, and this method is used to eliminate reactions that produce redundant equilibrium constraints. Since the equilibrium reactions must compensate for changes in the system that disturb their equilibrium, the equilibrium source terms are not forced identically to zero. Equilibrium is imposed by driving these source terms to the average value required to compensate for the perturbations caused by the other processes. Integration results for a cesium-air mechanism, a hydrogen-air mechanism, and a thermonuclear mechanism used in astrophysics are presented. One-dimensional flame and detonation results are presented for a single-step hydrogen mechanism and the thermonuclear mechanism, respectively
Tsventoukh, M. M.
2010-10-01
A study is made of the convective (interchange, or flute) plasma stability consistent with equilibrium in magnetic confinement systems with a magnetic field decreasing outward and large curvature of magnetic field lines. Algorithms are developed which calculate convective plasma stability from the Kruskal-Oberman kinetic criterion and in which the convective stability is iteratively consistent with MHD equilibrium for a given pressure and a given type of anisotropy in actual magnetic geometry. Vacuum and equilibrium convectively stable configurations in systems with a decreasing, highly curved magnetic field are calculated. It is shown that, in convectively stable equilibrium, the possibility of achieving high plasma pressures in the central region is restricted either by the expansion of the separatrix (when there are large regions of a weak magnetic field) or by the filamentation of the gradient plasma current (when there are small regions of a weak magnetic field, in which case the pressure drops mainly near the separatrix). It is found that, from the standpoint of equilibrium and of the onset of nonpotential ballooning modes, a kinetic description of convective stability yields better plasma confinement parameters in systems with a decreasing, highly curved magnetic field than a simpler MHD model and makes it possible to substantially improve the confinement parameters for a given type of anisotropy. For the Magnetor experimental compact device, the maximum central pressure consistent with equilibrium and stability is calculated to be as high as β ˜ 30%. It is shown that, for the anisotropy of the distribution function that is typical of a background ECR plasma, the limiting pressure gradient is about two times steeper than that for an isotropic plasma. From a practical point of view, the possibility is demonstrated of achieving better confinement parameters of a hot collisionless plasma in systems with a decreasing, highly curved magnetic field than those
Keshtkar, F.; Erjaee, G.; Boutefnouchet, M.
2014-01-01
In this article, a brief stability analysis of equilibrium points in nonlinear fractional order dynamical systems is given. Then, based on the first integral concept, a definition of planar Hamiltonian systems with fractional order introduced. Some interesting properties of these fractional Hamiltonian systems are also presented. Finally, we illustrate two examples to see the differences between fractional Hamiltonian systems with their classical order counterparts. NPRP . Grant Number: NP...
Equilibrium system analysis in a tokamak ignition experiment. Final report
Energy Technology Data Exchange (ETDEWEB)
Carrera, R.; Weldon, W.F.; Woodson, H.H.
1989-10-01
The objective of the IGNITEX Project is to produce and control ignited plasmas for scientific study in the simplest and least expensive way possible. The original concept was proposed by both physics and engineering researchers along the following line of thought. Question: Is there any theoretically simple, compact and reliable way of achieving fusion ignition according to the results of the fusion research program for the last decades? Answer: Yes. An experiment to be carried out in an ohmically heated compact tokamak device with 20 T field on plasma axis. Question: Is there any practical way to carry out that experiment at low cost in the near term? Answer: Yes. Using a single-turn coil magnet system with homopolar power supplies.
Equilibrium system analysis in a tokamak ignition experiment
Energy Technology Data Exchange (ETDEWEB)
Carrera, R.; Weldon, W.F.; Woodson, H.H.
1989-10-01
The objective of the IGNITEX Project is to produce and control ignited plasmas for scientific study in the simplest and least expensive way possible. The original concept was proposed by both physics and engineering researchers along the following line of thought. Question: Is there any theoretically simple, compact and reliable way of achieving fusion ignition according to the results of the fusion research program for the last decades Answer: Yes. An experiment to be carried out in an ohmically heated compact tokamak device with 20 T field on plasma axis. Question: Is there any practical way to carry out that experiment at low cost in the near term Answer: Yes. Using a single-turn coil magnet system with homopolar power supplies.
Energy and transverse momentum fluctuations in the equilibrium quantum systems
Energy Technology Data Exchange (ETDEWEB)
Gorenstein, M.I. [Bogolyubov Institute for Theoretical Physics, Kiev (Ukraine); Frankfurt Institute for Advanced Studies, Frankfurt (Germany); Rybczyński, M. [Institute of Physics, Jan Kochanowski University, Kielce (Poland)
2014-03-07
The fluctuations in the ideal quantum gases are studied using the strongly intensive measures Δ[A,B] and Σ[A,B] defined in terms of two extensive quantities A and B. In the present Letter, these extensive quantities are taken as the motional variable, A=X, the system energy E or transverse momentum P{sub T}, and number of particles, B=N. This choice is most often considered in studying the event-by-event fluctuations and correlations in high energy nucleus–nucleus collisions. The recently proposed special normalization ensures that Δ and Σ are dimensionless and equal to unity for fluctuations given by the independent particle model. In statistical mechanics, the grand canonical ensemble formulation within the Boltzmann approximation gives an example of independent particle model. Our results demonstrate the effects due to the Bose and Fermi statistics. Estimates of the effects of quantum statistics in the hadron gas at temperatures and chemical potentials typical for thermal models of hadron production in high energy collisions are presented. In the case of massless particles and zero chemical potential the Δ and Σ measures are calculated analytically/.
Equilibrium Statistical Thermodynamics of a Many-Particle System Coupled to an External Scalar Field
Salvino, R. E.
1990-01-01
The equilibrium thermodynamics of a many-particle assembly in the presence of an external scalar field is examined. Two types of scalar coupling are considered: an external field coupled to the particle density and an external scalar field coupled to the energy density. It is shown that the broken translational and rotational invariance of the system due to the external field is reflected in the macroscopic physics by loss of the usual extensivity property of the system and by means of anisotropy in the response of the system to changes in the system lengths or to the system shape. In addition, the assumptions used in local equilibrium analyses are shown to be incorrect in principle. Nonlocal effects due to the external field must be included in the determination of the equation of state. Simple model calculations for a system in an external gravitational field and an externally imposed temperature field are presented as illustrations.
Cloonan, Carrie A.; Andrew, Julie A.; Nichol, Carolyn A.; Hutchinson, John S.
2011-01-01
This article describes an activity that can be used as an inquiry-based laboratory or demonstration for either high school or undergraduate chemistry students to provide a basis for understanding both vapor pressure and the concept of dynamic phase equilibrium. The activity includes a simple setup to create a closed system of only water liquid and…
Convergence to equilibrium in competitive Lotka–Volterra and chemostat systems
Champagnat, Nicolas
2010-12-01
We study a generalized system of ODE\\'s modeling a finite number of biological populations in a competitive interaction. We adapt the techniques in Jabin and Raoul [8] and Champagnat and Jabin (2010) [2] to prove the convergence to a unique stable equilibrium. © 2010 Académie des sciences.
Restructured electric power systems analysis of electricity markets with equilibrium models
2010-01-01
Electricity market deregulation is driving the power energy production from a monopolistic structure into a competitive market environment. The development of electricity markets has necessitated the need to analyze market behavior and power. Restructured Electric Power Systems reviews the latest developments in electricity market equilibrium models and discusses the application of such models in the practical analysis and assessment of electricity markets.
Modeling the Equilibrium Bus Line Choice Behavior and Transit System Design with Oblivious Users
National Research Council Canada - National Science Library
Zhao, Chuan-Lin; Huang, Hai-Jun
2014-01-01
... a more realistic public transit system when considering the boundedly rational users. In the literature, user equilibrium models play an important role in the traffic assignment problems. By assuming that all road users behave in a completely rational way and seeking to minimize their own disutility, Wardrop [1] defined a state of route choice, the so-call...
Londono, A.; Jongmans, Mark; Schuur, Boelo; de Haan, A.B.
2012-01-01
Isobaric vapor–liquid equilibrium (VLE) data for the binary system monochloroacetic acid + dichloroacetic acid have been measured at 5, 7.5, and 10 kPa. The VLE data measured in this work is thermodynamically consistent according to the Herington area method. The non-ideal behavior in the vapor
Ge, Hao; Qian, Hong
2011-01-06
A theory for an non-equilibrium phase transition in a driven biochemical network is presented. The theory is based on the chemical master equation (CME) formulation of mesoscopic biochemical reactions and the mathematical method of large deviations. The large deviations theory provides an analytical tool connecting the macroscopic multi-stability of an open chemical system with the multi-scale dynamics of its mesoscopic counterpart. It shows a corresponding non-equilibrium phase transition among multiple stochastic attractors. As an example, in the canonical phosphorylation-dephosphorylation system with feedback that exhibits bistability, we show that the non-equilibrium steady-state (NESS) phase transition has all the characteristics of classic equilibrium phase transition: Maxwell construction, a discontinuous first-derivative of the 'free energy function', Lee-Yang's zero for a generating function and a critical point that matches the cusp in nonlinear bifurcation theory. To the biochemical system, the mathematical analysis suggests three distinct timescales and needed levels of description. They are (i) molecular signalling, (ii) biochemical network nonlinear dynamics, and (iii) cellular evolution. For finite mesoscopic systems such as a cell, motions associated with (i) and (iii) are stochastic while that with (ii) is deterministic. Both (ii) and (iii) are emergent properties of a dynamic biochemical network.
A novel four-wing non-equilibrium chaotic system and its circuit ...
Indian Academy of Sciences (India)
A novel four-wing non-equilibrium chaotic system and its circuit implementation. YUAN LIN1,2,∗, CHUNHUA WANG1, HAIZHEN HE1 and LI LI ZHOU1. 1College of Information Science and Engineering, Hunan University, Changsha 410082, China. 2College of Electrical and Information Engineering, Hunan Institute of ...
De Souza, Roger A; Martin, Manfred
2008-05-07
The use of an (18)O/(16)O exchange experiment as a means for probing surface space-charge layers in oxides is examined theoretically and experimentally. On the basis of a theoretical treatment, isotope penetration profiles are calculated for (18)O/(16)O exchange across a gas-solid interface and subsequent diffusion of the labelled isotope through an equilibrium space-charge layer depleted of mobile oxygen vacancies and into a homogeneous bulk phase. Profiles calculated for a range of conditions all have a characteristic shape: a sharp drop in isotope fraction close to the surface followed by a normal bulk diffusion profile. Experimental (18)O profiles in an exchanged (001) oriented single crystal of Fe-doped SrTiO(3) were measured by time-of-flight secondary ion mass spectrometry (ToF-SIMS). By extracting the space-charge potential from such profiles, we demonstrate that this method allows the spatially resolved characterization of space-charge layers at the surfaces of crystalline oxides under thermodynamically well-defined conditions.
Business Information Exchange System with Security, Privacy, and Anonymity
Directory of Open Access Journals (Sweden)
Sead Muftic
2016-01-01
Full Text Available Business Information Exchange is an Internet Secure Portal for secure management, distribution, sharing, and use of business e-mails, documents, and messages. It has three applications supporting three major types of information exchange systems: secure e-mail, secure instant messaging, and secure sharing of business documents. In addition to standard security services for e-mail letters, which are also applied to instant messages and documents, the system provides innovative features of privacy and full anonymity of users and their locations, actions, transactions, and exchanged resources. In this paper we describe design, implementation, and use of the system.
Dynamics of a mechanical system with multiple degrees of freedom out of thermal equilibrium
Feigel, A.
2017-05-01
Out of thermal equilibrium, an environment imposes effective mechanical forces on nanofabricated devices as well as on microscopic chemical or biological systems. Here we address the question of how to calculate these forces together with the response of the system from first principles. We show that an ideal gaslike environment, even near thermal equilibrium, can enforce a specific steady state on the system by creating effective potentials in otherwise homogeneous space. An example of stable and unstable rectifications of thermal fluctuations is presented using a modified Feynman-Smoluchowski ratchet with two degrees of freedom. Moreover, the stability of a steady configuration depends on its chiral symmetry. The transition rate probabilities and the corresponding kinetic equations are derived for a complex mechanical system with arbitrary degrees of freedom. This work, therefore, extends the applicability of mechanical systems as a toy model playground of statistical physics for active and living matter with multiple degrees of freedom.
Equilibrium configurations of the tethered three-body formation system and their nonlinear dynamics
Xu, Ming; Zhu, Jian-Min; Tan, Tian; Xu, Shi-Jie
2012-12-01
This paper considers nonlinear dynamics of tethered three-body formation system with their centre of mass staying on a circular orbit around the Earth, and applies the theory of space manifold dynamics to deal with the nonlinear dynamical behaviors of the equilibrium configurations of the system. Compared with the classical circular restricted three body system, sixteen equilibrium configurations are obtained globally from the geometry of pseudo-potential energy surface, four of which were omitted in the previous research. The periodic Lyapunov orbits and their invariant manifolds near the hyperbolic equilibria are presented, and an iteration procedure for identifying Lyapunov orbit is proposed based on the differential correction algorithm. The non-transversal intersections between invariant manifolds are addressed to generate homoclinic and heteroclinic trajectories between the Lyapunov orbits. (3,3)-and (2,1)-heteroclinic trajectories from the neighborhood of one collinear equilibrium to that of another one, and (3,6)- and (2,1)-homoclinic trajectories from and to the neighborhood of the same equilibrium, are obtained based on the Poincaré mapping technique.
An Electric Bus with a Battery Exchange System
Directory of Open Access Journals (Sweden)
Jeongyong Kim
2015-07-01
Full Text Available As part of the ongoing effort to be independent of petroleum resources and to be free from pollutant emission issues, various electric vehicles have been developed and tested through their integration with real world systems. In the current paper, yet another application specific EV for public transportation, an electric bus, is introduced and explained with results from the pilot test program which was carried out under real traffic conditions. The main feature of the current system is a battery exchanging mechanism mounted on the roof of the bus. The current configuration certainly requires an externally fabricated battery exchanging robot system that would complement the electric bus for a fully automated battery exchanging process. The major advantage of the current system is the quick re-charging of the electric energy through the physical battery exchange and the possible utilization of the battery exchange station as a mini scale energy storage system for grid system peak power shaving. With the total system solution approach for the public transportation system, it is fully expected to create outstanding business opportunities in number of areas such as battery suppliers, battery exchanging station management, battery leasing and many more.
Boundary-equilibrium bifurcations in piecewise-smooth slow-fast systems.
Kowalczyk, P; Glendinning, P
2011-06-01
In this paper we study the qualitative dynamics of piecewise-smooth slow-fast systems (singularly perturbed systems) which are everywhere continuous. We consider phase space topology of systems with one-dimensional slow dynamics and one-dimensional fast dynamics. The slow manifold of the reduced system is formed by a piecewise-continuous curve, and the differentiability is lost across the switching surface. In the full system the slow manifold is no longer continuous, and there is an O(ɛ) discontinuity across the switching manifold, but the discontinuity cannot qualitatively alter system dynamics. Revealed phase space topology is used to unfold qualitative dynamics of planar slow-fast systems with an equilibrium point on the switching surface. In this case the local dynamics corresponds to so-called boundary-equilibrium bifurcations, and four qualitative phase portraits are uncovered. Our results are then used to investigate the dynamics of a box model of a thermohaline circulation, and the presence of a boundary-equilibrium bifurcation of a fold type is shown.
Non-equilibrium steady states of quantum systems on star graphs
Energy Technology Data Exchange (ETDEWEB)
Mintchev, Mihail, E-mail: mintchev@df.unipi.it [Istituto Nazionale di Fisica Nucleare and Dipartimento di Fisica, Universita di Pisa, Largo Pontecorvo 3, 56127 Pisa (Italy)
2011-10-14
Non-equilibrium steady states of quantum fields on star graphs are explicitly constructed. These states are parametrized by the temperature and the chemical potential, associated with each edge of the graph. Time reversal invariance is spontaneously broken. We study in this general framework the transport properties of the Schroedinger and the Dirac systems on a star graph, modeling a quantum wire junction. The interaction, which drives the system away from equilibrium, is localized in the vertex of the graph. All point-like vertex interactions, giving rise to self-adjoint Hamiltonians possibly involving the minimal coupling to a static electromagnetic field in the ambient space, are considered. In this context, we compute the exact electric steady current and the non-equilibrium charge density. We also investigate the heat transport and derive the Casimir energy density away from equilibrium. The appearance of Friedel-type oscillations of the charge and energy densities along the edges of the graph is established. We focus finally on the noise power and discuss the non-trivial impact of the point-like interactions on the noise. (paper)
Phase rule calculations and the thermodynamics of reactive systems under chemical equilibrium
Directory of Open Access Journals (Sweden)
PLATT G. M.
1999-01-01
Full Text Available In this paper, we examine the resolution of some phase rule problems within the context of multiple chemical equilibrium reactions, using cubic equations of state and an activity coefficient model. Bubble and dew reactive surfaces, reactive azeotropic loci and reactive critical loci are generated and presented in graphical form. Also isobaric bubble and dew reactive enthalpy loci, which may be useful in the modeling of reactive distillation operations, are depicted. All the formalism here employed is developed within the coordinate transformation of Ung and Doherty, which is appropriate for equilibrium reactive or multireactive systems. The major contribution of this work is the determination of critical loci for reactive or multireactive equilibrium systems. Since it is known that for some class of chemical reactions the kinetics and product distribution exhibit high sensitivity to pressure near criticality, the present study may be useful as a predicting tool in these cases if the chemical equilibrium condition is not too far from the real phenomenon.
Wireless health data exchange for home healthcare monitoring systems.
Lee, Malrey; Gatton, Thomas M
2010-01-01
Ubiquitous home healthcare systems have been playing an increasingly significant role in the treatment and management of chronic diseases, such as diabetes and hypertension, but progress has been hampered by the lack of standardization in the exchange of medical health care information. In an effort to establish standardization, this paper proposes a home healthcare monitoring system data exchange scheme between the HL7 standard and the IEEE1451 standard. IEEE1451 is a standard for special sensor networks, such as industrial control and smart homes, and defines a suite of interfaces that communicate among heterogeneous networks. HL7 is the standard for medical information exchange among medical organizations and medical personnel. While it provides a flexible data exchange in health care domains, it does not provide for data exchange with sensors. Thus, it is necessary to develop a data exchange schema to convert data between the HL7 and the IEEE1451 standard. This paper proposes a schema that can exchange data between HL7 devices and the monitoring device, and conforms to the IEEE 1451 standard. The experimental results and conclusions of this approach are presented and show the feasibility of the proposed exchange schema.
Wireless Health Data Exchange for Home Healthcare Monitoring Systems
Directory of Open Access Journals (Sweden)
Malrey Lee
2010-04-01
Full Text Available Ubiquitous home healthcare systems have been playing an increasingly significant role in the treatment and management of chronic diseases, such as diabetes and hypertension, but progress has been hampered by the lack of standardization in the exchange of medical health care information. In an effort to establish standardization, this paper proposes a home healthcare monitoring system data exchange scheme between the HL7 standard and the IEEE1451 standard. IEEE1451 is a standard for special sensor networks, such as industrial control and smart homes, and defines a suite of interfaces that communicate among heterogeneous networks. HL7 is the standard for medical information exchange among medical organizations and medical personnel. While it provides a flexible data exchange in health care domains, it does not provide for data exchange with sensors. Thus, it is necessary to develop a data exchange schema to convert data between the HL7 and the IEEE1451 standard. This paper proposes a schema that can exchange data between HL7 devices and the monitoring device, and conforms to the IEEE 1451 standard. The experimental results and conclusions of this approach are presented and show the feasibility of the proposed exchange schema.
The Prognosis of the Phase Equilibrium Diagram of the System Al-Cu-Si
Florentina Cziple
2007-01-01
The paper presents a model for establishing the mathematical functions of the liquidus and solidus curves, from the binary diagrams Al-Si, Si-Cu, Cu-Al and their use in the prognosis of the phase equilibrium diagram from the ternary system Al-Cu-Si. We have studied the model of the non-ideal liquid solution of the regular type. The calculus and graphic plotting of the equations for the binary systems has been performed on the computer
Some properties of correlations of quantum lattice systems in thermal equilibrium
Energy Technology Data Exchange (ETDEWEB)
Fröhlich, Jürg, E-mail: juerg@phys.ethz.ch [Institut für Theoretische Physik, ETH Zürich (Switzerland); Ueltschi, Daniel, E-mail: daniel@ueltschi.org [Department of Mathematics, University of Warwick, Coventry CV4 7AL (United Kingdom)
2015-05-15
Simple proofs of uniqueness of the thermodynamic limit of KMS states and of the decay of equilibrium correlations are presented for a large class of quantum lattice systems at high temperatures. New quantum correlation inequalities for general Heisenberg models are described. Finally, a simplified derivation of a general result on power-law decay of correlations in 2D quantum lattice systems with continuous symmetries is given, extending results of McBryan and Spencer for the 2D classical XY model.
Wang, Sheng; Wang, Shudong
Methanol autothermal reforming was thermodynamically analyzed using FLUENT software. The calculation methodology using this software is simple and convenient, and its validity was confirmed by comparing the obtained data with previous studies. As a function of the effects of temperature, pressure, molar steam-to-carbon ratio (S/C), and molar oxygen-to-carbon ratio (O/C) on the objective products, favorable operational parameters were evaluated, under which H 2 yield maximizes, the CO molar fraction minimizes and carbon deposition can be eliminated. The equilibrium constants of the possible reactions involved in oxidative methanol steam reforming, coupled with the reaction mechanism for the entire investigated temperature range, were elucidated and discussed. On the basis of the concluded possible mechanisms, three areas are inferred. In each individual area, H 2 or CO yield reached a maximum, or solid C was efficiently suppressed. Therein, a favorable operational range is proposed to assure the most optimized product yield.
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.
Thermalization and out-of-equilibrium dynamics in open quantum many-body systems
Energy Technology Data Exchange (ETDEWEB)
Buchhold, Michael
2015-06-30
In this thesis, we address both the question whether or not a quantum system driven away from equilibrium is able to relax to a thermal state, which fulfills detailed balance, and if one can identify universal behavior in the non-equilibrium relaxation dynamics. As a first realization of driven quantum systems out of equilibrium, we investigate a system of Ising spins, interacting with the quantized radiation field in an optical cavity. For multiple cavity modes, this system forms a highly entangled and frustrated state with infinite correlation times, known as a quantum spin glass. In the thermalized system, the features of the spin glass are mirrored onto the photon degrees of freedom, leading to an emergent photon glass phase. Exploiting the inherent photon loss of the cavity, we make predictions of possible measurements on the escaping photons, which contain detailed information of the state inside the cavity and allow for a precise, non-destructive measurement of the glass state. As a further set of non-equilibrium systems, we consider one-dimensional quantum fluids driven out of equilibrium, whose universal low energy theory is formed by the so-called Luttinger Liquid description. In this thesis, we derive for the first time a kinetic equation for interacting Luttinger Liquids, which describes the time evolution of the excitation densities for arbitrary initial states. The resonant character of the interaction makes a straightforward derivation of the kinetic equation, using Fermis golden rule, impossible and we have to develop non-perturbative techniques in the Keldysh framework. We derive a closed expression for the time evolution of the excitation densities in terms of self-energies and vertex corrections. Close to equilibrium, the kinetic equation describes the exponential decay of excitations, with a decay rate σ{sup R}=ImΣ{sup R}, determined by the self-energy at equilibrium. However, for long times τ, it also reveals the presence of dynamical slow
Wu, Wei; Wang, Jin
2013-09-28
We established a potential and flux field landscape theory to quantify the global stability and dynamics of general spatially dependent non-equilibrium deterministic and stochastic systems. We extended our potential and flux landscape theory for spatially independent non-equilibrium stochastic systems described by Fokker-Planck equations to spatially dependent stochastic systems governed by general functional Fokker-Planck equations as well as functional Kramers-Moyal equations derived from master equations. Our general theory is applied to reaction-diffusion systems. For equilibrium spatially dependent systems with detailed balance, the potential field landscape alone, defined in terms of the steady state probability distribution functional, determines the global stability and dynamics of the system. The global stability of the system is closely related to the topography of the potential field landscape in terms of the basins of attraction and barrier heights in the field configuration state space. The effective driving force of the system is generated by the functional gradient of the potential field alone. For non-equilibrium spatially dependent systems, the curl probability flux field is indispensable in breaking detailed balance and creating non-equilibrium condition for the system. A complete characterization of the non-equilibrium dynamics of the spatially dependent system requires both the potential field and the curl probability flux field. While the non-equilibrium potential field landscape attracts the system down along the functional gradient similar to an electron moving in an electric field, the non-equilibrium flux field drives the system in a curly way similar to an electron moving in a magnetic field. In the small fluctuation limit, the intrinsic potential field as the small fluctuation limit of the potential field for spatially dependent non-equilibrium systems, which is closely related to the steady state probability distribution functional, is
Energy Technology Data Exchange (ETDEWEB)
Suzuki-Muresan, Tomo; Perrigaud, Katy; Vandenborre, Johan; Ribet, Solange; Grambow, Bernd [Nantes Univ., CNRS/IN2P3 (France). SUBATECH Unite Mixte de Recherche 6457; Takamasa, Inai [TOKAI Univ., Kanagawa (Japan)
2017-08-01
This work aims to assess the solubility and the surface reactivity of crystallized thorium at pH 3.0 in presence of three types of solids: synthesized powder at 1300 C, crushed kernel, and intact kernel. In this study, the kernel is composed by the core solid from high temperature reactors (HTR) sphere particles. The originality of this work consisted in following in a sequential order the kinetic of dissolution, the surface reactivity in presence of isotope tracer {sup 229}Th, and its desorption process. Long time experiments (634 days) allowed to get deeper understanding on the behavior of the surface reactivity in contact with the solution. Solubility values are ranging from 0.3 x 10{sup -7} mol.L{sup -1} to 3 x 10{sup -7} mol.L{sup -1} with a dissolution rate of 10{sup -6}-10{sup -4} g.m{sup -2} day{sup -1}. PHREEQC modeling showed that crystallized ThO{sub 2}(cr, 20 nm) phase controls the equilibrium in solution. Isotope exchange between {sup 229}Th and {sup 232}Th indicated that well-crystallized phase exist as an inert surface regarding to the absence of exchange between surface solid and solution.
Research on Heat Exchange Process in Aircraft Air Conditioning System
Chichindaev, A. V.
2017-11-01
Using of heat-exchanger-condenser in the air conditioning system of the airplane Tu-204 (Boeing, Airbus, Superjet 100, MS-21, etc.) for cooling the compressed air by the cold air with negative temperature exiting the turbine results in a number of operational problems. Mainly it’s frosting of the heat exchange surface, which is the cause of live-section channels frosting, resistance increasing and airflow in the system decreasing. The purpose of this work is to analyse the known freeze-up-fighting methods for heat-exchanger-condenser, description of the features of anti-icing protection and offering solutions to this problem. For the problem of optimizing the design of heat exchangers in this work used generalized criterion that describes the ratio of thermal resistances of cold and hot sections, which include: the ratio of the initial values of heat transfer agents flow state; heat exchange surface finning coefficients; factors which describes the ratio of operating parameters and finning area. By controlling the ratio of the thermal resistances can be obtained the desired temperature of the heat exchange surface, which would prevent freezing. The work presents the results of a numerical study of the effect of different combinations of regime and geometrical factors changes on reduction of the heat-exchanger-condenser freezing surface area, including using of variable ratio of thermal resistances.
Induced ferro-ferromagnetic exchange bias in nanocrystalline systems
Energy Technology Data Exchange (ETDEWEB)
Martínez-García, J.C.; Rivas, M.; García, J.A.
2015-03-01
An unusual magnetic hysteresis consisting of horizontally shifted and distorted loops appears in some Co-based nanocrystalline systems in which soft and hard ferromagnetic phases coexist. The bias field can be tuned at room temperature by premagnetising treatments. Several works attributed the origin of this effect to the dipolar interaction, while little attention has been paid to the exchange interaction contribution due to its short-range nature. In this paper the relative importance of the dipolar and exchange interactions is investigated by means of micromagnetic simulations. It is demonstrated that the exchange coupling, though a nearest-neighbour interaction, has far-reaching repercussions in the magnetic configuration, and substantially prevails over the magnetostatic interaction as the cause of the asymmetrical magnetisation reversal. The straightforward conclusion is that we are dealing with a ferro-ferromagnetic exchange bias effect. - Highlights: • Magnetic biphase nanocrystalline systems with biased hysteresis loops are presented. • Computational calculations including magnetostatic and exchange interactions have been made. • Exchange interaction largely prevails as the cause of the biasing effect. • The biasing of HL is due to exchange coupling of both ferromagnetic phases. • Assuming monodomain behaviour for the crystals allows simulating the experimental HL.
Plate Tectonics as a Far-From-Equilibrium Self-Organized Dissipative System
Anderson, D. L.
2001-12-01
A fluid above the critical Rayleigh number is far from equilibrium and spontaneously organizes itself into patterns involving the collective motion of large numbers of molecules which are resisted by the viscosity of the fluid. No external template is involved in forming the pattern. In 1928 Pearson showed that Bénard's experiments were driven by variations in surface tension at the top of the fluid and the surface motions drove convection in the fluid. In this case, the surface organized itself AND the underlying fluid. Both internal buoyancy driven flow and flow driven by surface forces can be far-from-equilibrium self-organized open systems that receive energy and matter from the environment. In the Earth, the cold thermal boundary layer at the surface drives plate tectonics and introduces temperature, shear and pressure gradients into the mantle that drive mantle convection. The mantle provides energy and material but may not provide the template. Plate tectonics is therefore a candidate for a far-from-equilibrium dissipative self-organizing system. Alternatively, one could view mantle convection as the self-organized system and the plates as simply the surface manifestation. Lithospheric architecture also imposes lateral temperature gradients onto the mantle which can drive and organize flow. Far-from-equilibrium self-organization requires; an open system, interacting parts, nonlinearities or feedbacks, an outside steady source of energy or matter, multiple possible states and a source of dissipation. In uniform fluids viscosity is the source of dissipation. Sources of dissipation in the plate system include bending, breaking, folding, shearing, tearing, collision and basal drag. These can change rapidly, in contrast to plate driving forces, and introduce the sort of fluctuations that can reorganize far-from-equilibrium systems. Global plate reorganizations can alternatively be thought of as convective overturns of the mantle, or thermal weakening of plates
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.
The Picture Exchange Communication System: Digital Photographs versus Picture Symbols
Jonaitis, Carmen
2011-01-01
The Picture Exchange Communication System (PECS) is an augmentative and alternative system (AAC) used to improve and increase communication for children with Autism Spectrum Disorder (ASD) and other developmental disorders. Research addressing the efficacy of this system is increasing; however, there is limited information published that evaluates…
Devine, Sean D
2016-02-01
Replication can be envisaged as a computational process that is able to generate and maintain order far-from-equilibrium. Replication processes, can self-regulate, as the drive to replicate can counter degradation processes that impact on a system. The capability of replicated structures to access high quality energy and eject disorder allows Landauer's principle, in conjunction with Algorithmic Information Theory, to quantify the entropy requirements to maintain a system far-from-equilibrium. Using Landauer's principle, where destabilising processes, operating under the second law of thermodynamics, change the information content or the algorithmic entropy of a system by ΔH bits, replication processes can access order, eject disorder, and counter the change without outside interventions. Both diversity in replicated structures, and the coupling of different replicated systems, increase the ability of the system (or systems) to self-regulate in a changing environment as adaptation processes select those structures that use resources more efficiently. At the level of the structure, as selection processes minimise the information loss, the irreversibility is minimised. While each structure that emerges can be said to be more entropically efficient, as such replicating structures proliferate, the dissipation of the system as a whole is higher than would be the case for inert or simpler structures. While a detailed application to most real systems would be difficult, the approach may well be useful in understanding incremental changes to real systems and provide broad descriptions of system behaviour. Copyright © 2016 The Author. Published by Elsevier Ireland Ltd.. All rights reserved.
Experimental Liquidus Studies of the Pb-Fe-Si-O System in Equilibrium with Metallic Pb
Shevchenko, M.; Jak, E.
2018-02-01
Phase equilibria of the Pb-Fe-Si-O system have been investigated at 943 K to 1773 K (670 °C to 1500 °C) for oxide liquid in equilibrium with liquid Pb metal and solid oxide phases: (a) quartz, tridymite, or cristobalite; (b) (fayalite + tridymite) or (fayalite + spinel); (c) spinel (Fe3O4); (d) complex lead-iron silicates (melanotekite PbO·FeO1.5·SiO2, barysilite 8PbO·FeO·6SiO2, 5PbO·FeO1.5·SiO2, and 6PbO·FeO1.5·SiO2); (e) lead silicates (Pb2SiO4, Pb11Si3O17); (f) lead ferrites (magnetoplumbite Pb1+ x Fe12- x O19- x solid solution range); and (g) lead oxide (PbO, massicot). High-temperature equilibration on primary phase or iridium substrates, followed by quenching and direct measurement of Pb, Fe, and Si concentrations in the phases with the electron probe X-ray microanalysis, has been used to accurately characterize the system in equilibrium with Pb metal. All results are projected onto the PbO-"FeO"-SiO2 plane for presentation purposes. The present study is the first systematic characterization of liquidus over a wide range of compositions in this system in equilibrium with metallic Pb.
Implementation of Medical Information Exchange System Based on EHR Standard.
Han, Soon Hwa; Lee, Min Ho; Kim, Sang Guk; Jeong, Jun Yong; Lee, Bi Na; Choi, Myeong Seon; Kim, Il Kon; Park, Woo Sung; Ha, Kyooseob; Cho, Eunyoung; Kim, Yoon; Bae, Jae Bong
2010-12-01
To develop effective ways of sharing patients' medical information, we developed a new medical information exchange system (MIES) based on a registry server, which enabled us to exchange different types of data generated by various systems. To assure that patient's medical information can be effectively exchanged under different system environments, we adopted the standardized data transfer methods and terminologies suggested by the Center for Interoperable Electronic Healthcare Record (CIEHR) of Korea in order to guarantee interoperability. Regarding information security, MIES followed the security guidelines suggested by the CIEHR of Korea. This study aimed to develop essential security systems for the implementation of online services, such as encryption of communication, server security, database security, protection against hacking, contents, and network security. The registry server managed information exchange as well as the registration information of the clinical document architecture (CDA) documents, and the CDA Transfer Server was used to locate and transmit the proper CDA document from the relevant repository. The CDA viewer showed the CDA documents via connection with the information systems of related hospitals. This research chooses transfer items and defines document standards that follow CDA standards, such that exchange of CDA documents between different systems became possible through ebXML. The proposed MIES was designed as an independent central registry server model in order to guarantee the essential security of patients' medical information.
Isolated many-body quantum systems far from equilibrium: Relaxation process and thermalization
Energy Technology Data Exchange (ETDEWEB)
Torres-Herrera, E. J.; Santos, Lea F. [Physics Department, Yeshiva University, New York, New York 10016 (United States)
2014-10-15
We present an overview of our recent numerical and analytical results on the dynamics of isolated interacting quantum systems that are taken far from equilibrium by an abrupt perturbation. The studies are carried out on one-dimensional systems of spins-1/2, which are paradigmatic models of many-body quantum systems. Our results show the role of the interplay between the initial state and the post-perturbation Hamiltonian in the relaxation process, the size of the fluctuations after equilibration, and the viability of thermalization.
Microcavity quantum-dot systems for non-equilibrium Bose-Einstein condensation
Energy Technology Data Exchange (ETDEWEB)
Piper, I M; Ediger, M; Wilson, A M; Wu, Y; Phillips, R T [Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Eastham, P R [School of Physics, Trinity College Dublin, Dublin 2 (Ireland); Hugues, M; Hopkinson, M, E-mail: imp24@cam.ac.u [Department of Electronic and Electrical Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom)
2010-09-01
We review the practical conditions required to achieve a non-equilibrium BEC driven by quantum dynamics in a system comprising a microcavity field mode and a distribution of localised two-level systems driven to a step-like population inversion profile. A candidate system based on eight 3.8nm layers of In{sub 0.23}Ga{sub 0.77}As in GaAs shows promising characteristics with regard to the total dipole strength which can be coupled to the field mode.
A 3D Fractional-Order Chaotic System with Only One Stable Equilibrium and Controlling Chaos
Directory of Open Access Journals (Sweden)
Shiyun Shen
2017-01-01
Full Text Available One 3D fractional-order chaotic system with only one locally asymptotically stable equilibrium is reported. To verify the chaoticity, the maximum Lyapunov exponent (MAXLE with respect to the fractional-order and chaotic attractors are obtained by numerical calculation for this system. Furthermore, by linear scalar controller consisting of a single state variable, one control scheme for stabilization of the 3D fractional-order chaotic system is suggested. The numerical simulations show the feasibility of the control scheme.
Energy Technology Data Exchange (ETDEWEB)
Chung, P.-Y. [R and D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); Soriano, Allan N. [R and D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); School of Chemical Engineering and Chemistry, Mapua Institute of Technology, Manila 1002 (Philippines); Leron, Rhoda B. [R and D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); Li, M.-H., E-mail: mhli@cycu.edu.t [R and D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China)
2010-06-15
In this study, a new set of data for the equilibrium solubility of carbon dioxide in the amine solvent system that consists of triethanolamine (TEA), piperazine (PZ), and water is presented. Equilibrium solubility values were obtained at T = (313.2, 333.2, and 353.2) K and pressures up to 153 kPa using the vapour-recirculation equilibrium cell. The TEA concentrations in the considered ternary (solvent) mixture were (2 and 3) kmol . m{sup -3} and those of PZ's were (0.5, 1.0, and 1.5) kmol . m{sup -3}. The solubility data (CO{sub 2} loading in the amine solution) obtained were correlated as a function of CO{sub 2} partial pressure, system temperature, and amine composition via the modified Kent-Eisenberg model. Results showed that the model applied is generally satisfactory in representing the CO{sub 2} absorption into mixed aqueous solutions of TEA and PZ.
Pelissetto, Andrea; Vicari, Ettore
2017-01-20
We study the off-equilibrium behavior of systems with short-range interactions, slowly driven across a thermal first-order transition, where the equilibrium dynamics is exponentially slow. We consider a dynamics that starts in the high-T phase at time t=t_{i}0 in the low-T phase, with a time-dependent temperature T(t)/T_{c}≈1-t/t_{s}, where t_{s} is the protocol time scale. A general off-equilibrium scaling (OS) behavior emerges in the limit of large t_{s}. We check it at the first-order transition of the two-dimensional q-state Potts model with q=20 and 10. The numerical results show evidence of a dynamic transition, where the OS functions show a spinodal-like singularity. Therefore, the general mean-field picture valid for systems with long-range interactions is qualitatively recovered, provided the time dependence is appropriately (logarithmically) rescaled.
Path-space variational inference for non-equilibrium coarse-grained systems
Harmandaris, Vagelis; Kalligiannaki, Evangelia; Katsoulakis, Markos; Plecháč, Petr
2016-06-01
In this paper we discuss information-theoretic tools for obtaining optimized coarse-grained molecular models for both equilibrium and non-equilibrium molecular simulations. The latter are ubiquitous in physicochemical and biological applications, where they are typically associated with coupling mechanisms, multi-physics and/or boundary conditions. In general the non-equilibrium steady states are not known explicitly as they do not necessarily have a Gibbs structure. The presented approach can compare microscopic behavior of molecular systems to parametric and non-parametric coarse-grained models using the relative entropy between distributions on the path space and setting up a corresponding path-space variational inference problem. The methods can become entirely data-driven when the microscopic dynamics are replaced with corresponding correlated data in the form of time series. Furthermore, we present connections and generalizations of force matching methods in coarse-graining with path-space information methods. We demonstrate the enhanced transferability of information-based parameterizations to different observables, at a specific thermodynamic point, due to information inequalities. We discuss methodological connections between information-based coarse-graining of molecular systems and variational inference methods primarily developed in the machine learning community. However, we note that the work presented here addresses variational inference for correlated time series due to the focus on dynamics. The applicability of the proposed methods is demonstrated on high-dimensional stochastic processes given by overdamped and driven Langevin dynamics of interacting particles.
Mélykúti, Bence; Hespanha, João P; Khammash, Mustafa
2014-08-06
Many biochemical reaction networks are inherently multiscale in time and in the counts of participating molecular species. A standard technique to treat different time scales in the stochastic kinetics framework is averaging or quasi-steady-state analysis: it is assumed that the fast dynamics reaches its equilibrium (stationary) distribution on a time scale where the slowly varying molecular counts are unlikely to have changed. We derive analytic equilibrium distributions for various simple biochemical systems, such as enzymatic reactions and gene regulation models. These can be directly inserted into simulations of the slow time-scale dynamics. They also provide insight into the stimulus-response of these systems. An important model for which we derive the analytic equilibrium distribution is the binding of dimer transcription factors (TFs) that first have to form from monomers. This gene regulation mechanism is compared to the cases of the binding of simple monomer TFs to one gene or to multiple copies of a gene, and to the cases of the cooperative binding of two or multiple TFs to a gene. The results apply equally to ligands binding to enzyme molecules.
Roles of Energy Dissipation in a Liquid-Solid Transition of Out-of-Equilibrium Systems
Directory of Open Access Journals (Sweden)
Yuta Komatsu
2015-08-01
Full Text Available Self-organization of active matter as well as driven granular matter in nonequilibrium dynamical states has attracted considerable attention not only from the fundamental and application viewpoints but also as a model to understand the occurrence of such phenomena in nature. These systems share common features originating from their intrinsically out-of-equilibrium nature, and how energy dissipation affects the state selection in such nonequilibrium states remains elusive. As a simple model system, we consider a nonequilibrium stationary state maintained by continuous energy input, relevant to industrial processing of granular materials by vibration and/or flow. More specifically, we experimentally study roles of dissipation in self-organization of a driven granular particle monolayer. We find that the introduction of strong inelasticity entirely changes the nature of the liquid-solid transition from two-step (nearly continuous transitions (liquid-hexatic-solid to a strongly discontinuous first-order-like one (liquid-solid, where the two phases with different effective temperatures can coexist, unlike thermal systems, under a balance between energy input and dissipation. Our finding indicates a pivotal role of energy dissipation and suggests a novel principle in the self-organization of systems far from equilibrium. A similar principle may apply to active matter, which is another important class of out-of-equilibrium systems. On noting that interaction forces in active matter, and particularly in living systems, are often nonconservative and dissipative, our finding may also shed new light on the state selection in these systems.
Information Geometry of Non-Equilibrium Processes in a Bistable System with a Cubic Damping
Directory of Open Access Journals (Sweden)
Rainer Hollerbach
2017-06-01
Full Text Available A probabilistic description is essential for understanding the dynamics of stochastic systems far from equilibrium, given uncertainty inherent in the systems. To compare different Probability Density Functions (PDFs, it is extremely useful to quantify the difference among different PDFs by assigning an appropriate metric to probability such that the distance increases with the difference between the two PDFs. This metric structure then provides a key link between stochastic systems and information geometry. For a non-equilibrium process, we define an infinitesimal distance at any time by comparing two PDFs at times infinitesimally apart and sum these distances in time. The total distance along the trajectory of the system quantifies the total number of different states that the system undergoes in time and is called the information length. By using this concept, we investigate the information geometry of non-equilibrium processes involved in disorder-order transitions between the critical and subcritical states in a bistable system. Specifically, we compute time-dependent PDFs, information length, the rate of change in information length, entropy change and Fisher information in disorder-to-order and order-to-disorder transitions and discuss similarities and disparities between the two transitions. In particular, we show that the total information length in order-to-disorder transition is much larger than that in disorder-to-order transition and elucidate the link to the drastically different evolution of entropy in both transitions. We also provide the comparison of the results with those in the case of the transition between the subcritical and supercritical states and discuss implications for fitness.
NON-EQUILIBRIUM DYNAMICS OF MANY-BODY QUANTUM SYSTEMS: FUNDAMENTALS AND NEW FRONTIER
Energy Technology Data Exchange (ETDEWEB)
DeMille, David; LeHur, Karyn
2013-11-27
Rapid progress in nanotechnology and naofabrication techniques has ushered in a new era of quantum transport experiments. This has in turn heightened the interest in theoretical understanding of nonequilibrium dynamics of strongly correlated quantum systems. This project has advanced the frontiers of understanding in this area along several fronts. For example, we showed that under certain conditions, quantum impurities out of equilibrium can be reformulated in terms of an effective equilibrium theory; this makes it possible to use the gamut of tools available for quantum systems in equilibrium. On a different front, we demonstrated that the elastic power of a transmitted microwave photon in circuit QED systems can exhibit a many-body Kondo resonance. We also showed that under many circumstances, bipartite fluctuations of particle number provide an effective tool for studying many-body physics—particularly the entanglement properties of a many-body system. This implies that it should be possible to measure many-body entanglement in relatively simple and tractable quantum systems. In addition, we studied charge relaxation in quantum RC circuits with a large number of conducting channels, and elucidated its relation to Kondo models in various regimes. We also extended our earlier work on the dynamics of driven and dissipative quantum spin-boson impurity systems, deriving a new formalism that makes it possible to compute the full spin density matrix and spin-spin correlation functions beyond the weak coupling limit. Finally, we provided a comprehensive analysis of the nonequilibrium transport near a quantum phase transition in the case of a spinless dissipative resonant-level model. This project supported the research of two Ph.D. students and two postdoctoral researchers, whose training will allow them to further advance the field in coming years.
The Prognosis of the Phase Equilibrium Diagram of the System Al-Cu-Si
Directory of Open Access Journals (Sweden)
Florentina Cziple
2007-10-01
Full Text Available The paper presents a model for establishing the mathematical functions of the liquidus and solidus curves, from the binary diagrams Al-Si, Si-Cu, Cu-Al and their use in the prognosis of the phase equilibrium diagram from the ternary system Al-Cu-Si. We have studied the model of the non-ideal liquid solution of the regular type. The calculus and graphic plotting of the equations for the binary systems has been performed on the computer
DEFF Research Database (Denmark)
Awan, Javeed; Thomsen, Kaj; Coquelet, Christophe
2010-01-01
In this work, vapor−liquid equilibrium (VLE) measurements of propyl mercaptan (PM) in pure water were performed at three different temperatures, (303, 323, and 365) K, with a pressure variation from (1 to 8) MPa. The total system pressure was maintained by CH4. The inlet mole fraction of propyl...... mercaptan in all experiments was the same, around 4.5·10−4 in the liquid phase. The objective was to provide experimental VLE data points of the propyl mercaptan + methane + water system for modeling since there is a lack of available data. These data will allow the industrial modeling of sulfur emission...
Directory of Open Access Journals (Sweden)
Luis Rabelo
2011-01-01
Full Text Available We propose and demonstrate a new methodology to stabilize systems with complex dynamics like the supply chain. This method is based on the accumulated deviations from equilibrium (ADE. It is most beneficial for controlling system dynamic models characterized by multiple types of delays, many interacting variables, and feedback processes. We employ the classical version of particle swarm optimization as the optimization approach due to its performance in multidimensional space, stochastic properties, and global reach. We demonstrate the effectiveness of our method based on ADE using a manufacturing-supply-chain case study.
Comparative field performance of three different gas exchange systems
Directory of Open Access Journals (Sweden)
G. F. Midgley
1997-12-01
Full Text Available We compared portable and continuously monitoring gas exchange systems under field conditions, using Protea glabra Thunb. as a test species. The aim was to determine if the same patterns of gas exchange and ancillary parameters could be obtained with rather different measurement systems, and whether the same interpretation and conclusions about environmental control of gas exchange could be drawn. The following systems were compared: 1, a ‘closed’ portable 1RGA manufactured by Ll-Cor (LI-6200; 2, an ‘open’ portable porometer manufactured by Walz; and 3, a continuously monitoring minicuvette system with temperature control facility, also manufactured by Walz. All three systems yielded similar diurnal curves for CO2 uptake, although absolute flux values for the minicuvette system were lower than those obtained for the portable systems. This was likely due to stem respiration and self-shading of leaves on the shoot enclosed in the minicuvette. Differences in sampling technique between the two portable systems, primarily with regard to changes in leaf orientation, resulted in some differences in absolute values of gas fluxes and ancillary parameters such as leaf temperature and leaf to air vapour pressure difference. However, data from all three systems allowed similar interpretations to be made about the environmental dependencies of gas exchange patterns. It appears that each system has certain drawbacks associated with widely varying field conditions. A combination of portable and continuous monitoring techniques would seem to be the most powerful approach to investigating the gas exchange patterns of terrestrial plants in their natural environment.
Fluctuation-dissipation theorem in isolated quantum systems out of equilibrium
Khatami, Ehsan; Pupillo, Guido; Srednicki, Mark; Rigol, Marcos
2014-05-01
We study the validity of the fluctuation-dissipation theorem for an isolated quantum system of harmonically trapped dipolar molecules taken out of equilibrium by means of a quench, a sudden change in the Hamiltonian parameters. We find that the integrability of the system plays a crucial role in the validity of the fluctuation-dissipation theorem. Namely, the system thermalizes according to the eigenstate thermalization hypothesis and the theorem holds if the system is nonintegrable after the quench. However, it fails if the system is integrable, unless the initial state is an eigenstate of a nonintegrable Hamiltonian, in which case the system still thermalizes despite the eigenstate thermalization hypothesis failing to describe it.
Fresch, Barbara; Moro, Giorgio J
2010-07-21
A system composed of identical spins and described by a quantum mechanical pure state is analyzed within the statistical framework presented in Part I of this work. We explicitly derive the typical values of the entropy, of the energy, and of the equilibrium reduced density matrix of a subsystem for the two different statistics introduced in Part I. In order to analyze their consistency with thermodynamics, these quantities of interest are evaluated in the limit of large number of components of the isolated system. The main results can be summarized as follows: typical values of the entropy and of the equilibrium reduced density matrix as functions of the internal energy in the fixed expectation energy ensemble do not satisfy the requirement of thermodynamics. On the contrary, the thermodynamical description is recovered from the random pure state ensemble (RPSE), provided that one considers systems large enough. The thermodynamic limit of the considered properties for the spin system reveals a number of important features. First canonical statistics (and thus, canonical typicality as long as the fluctuations around the average value are small) emerges without the need of assuming the microcanonical space for the global pure state. Moreover, we rigorously prove (i) the equivalence of the "global temperature," derived from the entropy equation of state, with the "local temperature" determining the canonical state of the subsystems; and (ii) the equivalence between the RPSE typical entropy and the canonical entropy for the overall system.
Standard Data Exchanges for Distribution System Management
Energy Technology Data Exchange (ETDEWEB)
Thomas E. McDermott
2007-10-05
Databases and software tools for electric power distribution systems have not been integrated, and this leads to extra costs and restrictions imposed on utilities and other stakeholders. For example, distributed resource integration studies and modern grid technology assessments are more difficult and costly. New vendors face high market entry barriers, because it’s necessary to interface with large and customized data systems at each potential utility customer. This project promotes data and software tool integration, through a set of data translators based on a common object model. The data translators are delivered as open-source software, using appropriate Web software technologies. The parties who benefit include electric utilities (and their ratepayers), researchers at government laboratories and universities, small software companies wishing to enter the electric utility market, and parties wishing to interconnect distributed generation to a utility system.
Pshenichnikov, A F
2000-01-01
The Monte Carlo method is used to study the equilibrium magnetization of a 3D system of superparamagnetic particles taking into account the steric and dipole-dipole interparticle interactions. Two types of systems are considered: magnetic fluids and solidified ferrocolloids containing randomly spatially distributed particles with negligible energy of magnetic anisotropy. The results of numerical simulations confirm the universality of Langevin susceptibility as a main dimensionless parameter determining the influence of interparticle interactions on the magnetization of the system for moderate values of the aggregation parameter. The obtained results are in good agreement with theoretical and experimental data. At large values of the aggregation parameter, the clustering of particles in magnetic fluids is observed resulting in a reduction of their magnetization as compared to solidified systems. It is shown that the magnetization of solidified systems can be well described by the modified effective field appr...
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.
Modeling of gamma/gamma-prime phase equilibrium in the nickel-aluminum system
Sanchez, J. M.; Barefoot, J. R.; Jarrett, R. N.; Tien, J. K.
1984-01-01
A theoretical model is proposed for the determination of phase equilibrium in alloys, taking into consideration dissimilar lattice parameters. Volume-dependent pair interactions are introduced by means of phenomenological Lennard-Jones potentials and the configurational entropy of the system is treated in the tetrahedron approximation of the cluster variation method. The model is applied to the superalloy-relevant, nickel-rich, gamma/gamma-prime phase region of the Ni-Al phase diagram. The model predicts reasonable values for the lattice parameters and the enthalpy of formation as a function of composition, and the calculated phase diagram closely approximates the experimental diagram.
Lu, Jianfeng; Zhou, Zhennan
2017-04-21
In this work, a novel ring polymer representation for a multi-level quantum system is proposed for thermal average calculations. The proposed representation keeps the discreteness of the electronic states: besides position and momentum, each bead in the ring polymer is also characterized by a surface index indicating the electronic energy surface. A path integral molecular dynamics with surface hopping (PIMD-SH) dynamics is also developed to sample the equilibrium distribution of the ring polymer configurational space. The PIMD-SH sampling method is validated theoretically and by numerical examples.
Jones, Kevin
Midwest Independent Transmission System Operator, Inc. (MISO) is a non-profit regional transmission organization (RTO) that oversees electricity production and transmission across thirteen states and one Canadian province. MISO also operates an electronic exchange for buying and selling electricity for each of its five regional hubs. MISO oversees two types of markets. The forward market, which is referred to as the day-ahead (DA) market, allows market participants to place demand bids and supply offers on electricity to be delivered at a specified hour the following day. The equilibrium price, known as the locational marginal price (LMP), is determined by MISO after receiving sale offers and purchase bids from market participants. MISO also coordinates a spot market, which is known as the real-time (RT) market. Traders in the real-time market must submit bids and offers by thirty minutes prior to the hour for which the trade will be executed. After receiving purchase and sale offers for a given hour in the real time market, MISO then determines the LMP for that particular hour. The existence of the DA and RT markets allows producers and retailers to hedge against the large fluctuations that are common in electricity prices. Hedge ratios on the MISO exchange are estimated using various techniques. No hedge ratio technique examined consistently outperforms the unhedged portfolio in terms of variance reduction. Consequently, none of the hedge ratio methods in this study meet the general interpretation of FASB guidelines for a highly effective hedge. One of the major goals of deregulation is to bring about competition and increased efficiency in electricity markets. Previous research suggests that electricity exchanges may not be weak-form market efficient. A simple moving average trading rule is found to produce statistically and economically significant profits on the MISO exchange. This could call the long-term survivability of the MISO exchange into question.
Non-equilibrium transitions in multiscale systems with a bifurcating slow manifold
Grafke, Tobias; Vanden-Eijnden, Eric
2017-09-01
Noise-induced transitions between metastable fixed points in systems evolving on multiple time scales are analyzed in situations where the time scale separation gives rise to a slow manifold with bifurcation. This analysis is performed within the realm of large deviation theory. It is shown that these non-equilibrium transitions make use of a reaction channel created by the bifurcation structure of the slow manifold, leading to vastly increased transition rates. Several examples are used to illustrate these findings, including an insect outbreak model, a system modeling phase separation in the presence of evaporation, and a system modeling transitions in active matter self-assembly. The last example involves a spatially extended system modeled by a stochastic partial differential equation.
Su, Ji; Yang, Lisha; Lu, Mi; Lin, Hongfei
2015-03-01
A highly efficient, reversible hydrogen storage-evolution process has been developed based on the ammonium bicarbonate/formate redox equilibrium over the same carbon-supported palladium nanocatalyst. This heterogeneously catalyzed hydrogen storage system is comparable to the counterpart homogeneous systems and has shown fast reaction kinetics of both the hydrogenation of ammonium bicarbonate and the dehydrogenation of ammonium formate under mild operating conditions. By adjusting temperature and pressure, the extent of hydrogen storage and evolution can be well controlled in the same catalytic system. Moreover, the hydrogen storage system based on aqueous-phase ammonium formate is advantageous owing to its high volumetric energy density. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Quantum Correlations, Separability, and Quantum Coherence Length in Equilibrium Many-Body Systems
Malpetti, Daniele; Roscilde, Tommaso
2016-09-01
Nonlocality is a fundamental trait of quantum many-body systems, both at the level of pure states, as well as at the level of mixed states. Because of nonlocality, mixed states of any two subsystems are correlated in a stronger way than what can be accounted for by considering the correlated probabilities of occupying some microstates. In the case of equilibrium mixed states, we explicitly build two-point quantum correlation functions, which capture the specific, superior correlations of quantum systems at finite temperature, and which are directly accessible to experiments when correlating measurable properties. When nonvanishing, these correlation functions rule out a precise form of separability of the equilibrium state. In particular, we show numerically that quantum correlation functions generically exhibit a finite quantum coherence length, dictating the characteristic distance over which degrees of freedom cannot be considered as separable. This coherence length is completely disconnected from the correlation length of the system—as it remains finite even when the correlation length of the system diverges at finite temperature—and it unveils the unique spatial structure of quantum correlations.
Energy Technology Data Exchange (ETDEWEB)
Charin, Rafael M. [Department of Chemical Engineering, Federal University of Parana (UFPR), Polytechnic Center (DTQ/ST/UFPR), Jardim das Americas, Curitiba 82530-990, PR (Brazil); Department of Food Engineering, URI - Campus de Erechim, Av. Sete de Setembro, 1621, Erechim 99700-000, RS (Brazil); Corazza, Marcos L.; Ndiaye, Papa M. [Department of Chemical Engineering, Federal University of Parana (UFPR), Polytechnic Center (DTQ/ST/UFPR), Jardim das Americas, Curitiba 82530-990, PR (Brazil); Rigo, Aline A.; Mazutti, Marcio A. [Department of Food Engineering, URI - Campus de Erechim, Av. Sete de Setembro, 1621, Erechim 99700-000, RS (Brazil); Vladimir Oliveira, J., E-mail: vladimir@uricer.edu.b [Department of Food Engineering, URI - Campus de Erechim, Av. Sete de Setembro, 1621, Erechim 99700-000, RS (Brazil)
2011-03-15
Reported in this work are phase equilibrium data at high pressures for the binary and ternary systems formed by {l_brace}propane + N,N-dimethylformamide (DMF) + methanol{r_brace}. Phase equilibrium measurements were performed in a high-pressure, variable-volume view cell, following the static synthetic method for obtaining the experimental bubble and dew points transition data over the temperature range of (363 to 393) K, pressures up to 11.5 MPa and overall mole fraction of the lighter component varying from 0.1 to 0.995. For the systems investigated, vapour-liquid (VLE), liquid-liquid (LLE) and vapour-liquid-liquid (VLLE) phase transitions were visually recorded. Results show that the systems investigated present UCST (upper critical solution temperature) phase transition curves with an UCEP (upper critical end point) at a temperature higher than the propane critical temperature. The experimental data were modelled using the Peng-Robinson equation of state with the Wong-Sandler and the classical quadratic mixing rules, affording a satisfactory representation of the experimental data.
Training Paraprofessionals to Implement the Picture Exchange Communication System (PECS)
Sloman, Glenn Matthew
2010-01-01
Based on Skinner's "Verbal Behavior" (1957), the picture exchange communication system (PECS) was designed to teach children with autism functional verbal behavior. Much research has demonstrated the effectiveness and efficiency of PECS in building verbal behavior. However, because PECS training is typically presented in a group format and later…
Data Exchange Inventory System for Telecommunications and Systems Operations (DEXI-OTSO)
Social Security Administration — This Data Exchange Inventory (DEXI) for the Office of Telecommunications and System Operations, (OTSO) Network Troubleshooting is a browser-based inventory database...
Interfacial spin cluster effects in exchange bias systems
Energy Technology Data Exchange (ETDEWEB)
Carpenter, R., E-mail: rc548@york.ac.uk; Vallejo-Fernandez, G.; O' Grady, K. [Department of Physics, The University of York, York YO10 5DD (United Kingdom)
2014-05-07
In this work, the effect of exchange bias on the hysteresis loop of CoFe is observed. The evolution of the coercivities and the shift of the hysteresis loop during the annealing process has been measured for films deposited on NiCr and Cu seed layers. Through comparison of the as deposited and field annealed loops, it is clear that for an exchange biased material, the two coercivities are due to different reversal processes. This behaviour is attributed to spin clusters at the ferromagnet/antiferromagnet interface, which behave in a similar manner to a fine particle system.
DEFF Research Database (Denmark)
Bojesen, Inge Norby; Bojesen, Eigil
1992-01-01
Biokemi, erythrocyte ghosts, pamitate, bovine serum albumin, long-chain fatty acids, equilibrium constants......Biokemi, erythrocyte ghosts, pamitate, bovine serum albumin, long-chain fatty acids, equilibrium constants...
Energy Technology Data Exchange (ETDEWEB)
Cramer, M [Institut fuer Theoretische Physik, Albert-Einstein Allee 11, Universitaet Ulm, D-89069 Ulm (Germany); Eisert, J, E-mail: marcus.cramer@macnews.d, E-mail: jense@qipc.or [Institute for Mathematical Sciences, Imperial College London, Prince' s Gardens, London SW7 2PE (United Kingdom)
2010-05-15
We prove that quantum many-body systems on a one-dimensional lattice locally relax to Gaussian states under non-equilibrium dynamics generated by a bosonic quadratic Hamiltonian. This is true for a large class of initial states-pure or mixed-which have to satisfy merely weak conditions concerning the decay of correlations. The considered setting is a proven instance of a situation where dynamically evolving closed quantum systems locally appear as if they had truly relaxed, to maximum entropy states for fixed second moments. This furthers the understanding of relaxation in suddenly quenched quantum many-body systems. The proof features a non-commutative central limit theorem for non-i.i.d. random variables, showing convergence to Gaussian characteristic functions, giving rise to trace-norm closeness. We briefly link our findings to the ideas of typicality and concentration of measure.
Seasonal thermal energy storage in shallow geothermal systems: thermal equilibrium stage
Directory of Open Access Journals (Sweden)
Nowamooz Hossein
2016-01-01
Full Text Available This paper is dedicated to the study of seasonal heat storage in shallow geothermal installations in unsaturated soils for which hydrothermal properties such as degree of saturation and thermal conductivity vary with time throughout the profile. In the model, a semi-analytical model which estimates time-spatial thermal conductivity is coupled with a 2D cylindrical heat transfer modeling using finite difference method. The variation of temperature was obtained after 3 heating and cooling cycles for the different types of loads with maximum thermal load of qmax = 15 W.m−1 with variable angular frequency (8 months of heating and 4 months of cooling.and constant angular frequency (6 months of heating and 6 months of cooling to estimate the necessary number of cycles to reach the thermal equilibrium stage. The results show that we approach a thermal equilibrium stage where the same variation of temperature can be observed in soils after several heating and cooling cycles. Based on these simulations, the necessary number of cycles can be related to the total applied energy on the system and the minimum number of cycles is for a system with the total applied energy of 1.9qmax.
Majda, Andrew J; Gershgorin, Boris
2011-08-02
Understanding and improving the predictive skill of imperfect models for complex systems in their response to external forcing is a crucial issue in diverse applications such as for example climate change science. Equilibrium statistical fidelity of the imperfect model on suitable coarse-grained variables is a necessary but not sufficient condition for this predictive skill, and elementary examples are given here demonstrating this. Here, with equilibrium statistical fidelity of the imperfect model, a direct link is developed between the predictive fidelity of specific test problems in the training phase where the perfect natural system is observed and the predictive skill for the forced response of the imperfect model by combining appropriate concepts from information theory with other concepts based on the fluctuation dissipation theorem. Here a suite of mathematically tractable models with nontrivial eddy diffusivity, variance, and intermittent non-Gaussian statistics mimicking crucial features of atmospheric tracers together with stochastically forced standard eddy diffusivity approximation with model error are utilized to illustrate this link.
Junkers, Thomas; Barner-Kowollik, Christopher; Coote, Michelle L
2011-12-01
In a recent article (W. Meiser, M. Buback, Assessing the RAFT Equilibrium Constant via Model Systems: An EPR Study, Macromol. Rapid Commun. 2011, 18, 1490-1494), it is claimed that evidence is found that unequivocally proves that quantum mechanical calculations assessing the equilibrium constant and fragmentation rate coefficients in dithiobenzoate-mediated reversible addition fragmentation transfer (RAFT) systems are beset with a considerable uncertainty. In the present work, we show that these claims made by Meiser and Buback are beset with a model dependency, as a critical key parameter in their data analysis - the addition rate coefficient of the radicals attacking the C=S double bond in the dithiobenzoate - induces a model insensitivity into the data analysis. Contrary to the claims made by Meiser and Buback, their experimental results can be brought into agreement with the quantum chemical calculations if a lower addition rate coefficient of cyanoisopropyl radicals (CIP) to the CIP dithiobenzoate (CPDB) is assumed. To resolve the model dependency, the addition rate coefficient of CIP radicals to CPDB needs to be determined as a matter of priority. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Exchange bias of patterned systems: Model and numerical simulation
Energy Technology Data Exchange (ETDEWEB)
Garcia, Griselda [Facultad de Fisica, P. Universidad Catolica de Chile, Casilla 306, Santiago 7820436 (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnologia, CEDENNA, Avda. Ecuador 3493, Santiago (Chile); Kiwi, Miguel, E-mail: mkiwi@puc.c [Facultad de Fisica, P. Universidad Catolica de Chile, Casilla 306, Santiago 7820436 (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnologia, CEDENNA, Avda. Ecuador 3493, Santiago (Chile); Mejia-Lopez, Jose; Ramirez, Ricardo [Facultad de Fisica, P. Universidad Catolica de Chile, Casilla 306, Santiago 7820436 (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnologia, CEDENNA, Avda. Ecuador 3493, Santiago (Chile)
2010-11-15
The magnitude of the exchange bias field of patterned systems exhibits a notable increase in relation to the usual bilayer systems, where a continuous ferromagnetic film is deposited on an antiferromagnet insulator. Here we develop a model, and implement a Monte Carlo calculation, to interpret the experimental observations which is consistent with experimental results, on the basis of assuming a small fraction of spins pinned ferromagnetically in the antiferromagnetic interface layer.
Yumei Li
2014-01-01
Isobaric vapor-liquid equilibrium (VLE) data for the cyclopentane and tetrahydrofuran (THF) system were measured at 101.3 kPa by using an equilibrium still. Thermodynamic consistency of the experimental data was confirmed by means of the Herington method. The experimental data were correlated and calculated by the Margules, Van Laar and Wilson activity-coefficient models, respectively. The Wilson and Van Laar activity-coefficient models are better than the Margules activity-coefficient model ...
Spooner, Stephen; Rahnama, Alireza; Warnett, Jason M; Williams, Mark A; Li, Zushu; Sridhar, Seetharaman
2017-10-30
Kinetic restriction of a thermodynamically favourable equilibrium is a common theme in materials processing. The interfacial instability in systems where rate of material exchange is far greater than the mass transfer through respective bulk phases is of specific interest when tracking the transient interfacial area, a parameter integral to short processing times for productivity streamlining in all manufacturing where interfacial reaction occurs. This is even more pertinent in high-temperature systems for energy and cost savings. Here the quantified physical pathway of interfacial area change due to material exchange in liquid metal-molten oxide systems is presented. In addition the predicted growth regime and emulsification behaviour in relation to interfacial tension as modelled using phase-field methodology is shown. The observed in-situ emulsification behaviour links quantitatively the geometry of perturbations as a validation method for the development of simulating the phenomena. Thus a method is presented to both predict and engineer the formation of micro emulsions to a desired specification.
Les Houches Summer School : Strongly Interacting Quantum Systems out of Equilibrium
Millis, Andrew J; Parcollet, Olivier; Saleur, Hubert; Cugliandolo, Leticia F
2016-01-01
Over the last decade new experimental tools and theoretical concepts are providing new insights into collective nonequilibrium behavior of quantum systems. The exquisite control provided by laser trapping and cooling techniques allows us to observe the behavior of condensed bose and degenerate Fermi gases under nonequilibrium drive or after quenches' in which a Hamiltonian parameter is suddenly or slowly changed. On the solid state front, high intensity short-time pulses and fast (femtosecond) probes allow solids to be put into highly excited states and probed before relaxation and dissipation occur. Experimental developments are matched by progress in theoretical techniques ranging from exact solutions of strongly interacting nonequilibrium models to new approaches to nonequilibrium numerics. The summer school Strongly interacting quantum systems out of equilibrium' held at the Les Houches School of Physics as its XCIX session was designed to summarize this progress, lay out the open questions and define dir...
Milazzo, P. M.; Botvina, A. S.; Vannini, G.; Bruno, M.; Colonna, N.; D'Agostino, M.; Gramegna, F.; Iori, I.; Margagliotti, G. V.; Mastinu, P. F.; Moroni, A.; Rui, R.
2002-08-01
Studies on the isospin of fragments resulting from the disassembly of highly excited large thermal-like nuclear emitting sources, formed in the 197Au+197Au reaction at 35 MeV/nucleon beam energy, are presented. Two different decay systems (the quasiprojectile formed in midperipheral reactions and the unique source coming from the incomplete fusion of projectile and target in the most central collisions) were considered; these emitting sources have the same initial N/Z ratio and excitation energy (E*~=5-6 MeV/nucleon), but different size. Their charge yields and isotopic content of the fragments show different distributions. It is observed that the neutron content of intermediate mass fragments increases with the size of the source. These evidences are consistent with chemical equilibrium reached in the systems. This fact is confirmed by the analysis with the statistical multifragmentation model.
New Chaotic Dynamical System with a Conic-Shaped Equilibrium Located on the Plane Structure
Directory of Open Access Journals (Sweden)
Jiri Petrzela
2017-09-01
Full Text Available This paper presents a new autonomous deterministic dynamical system with equilibrium degenerated into a plane-oriented hyperbolic geometrical structure. It is demonstrated via numerical analysis and laboratory experiments that the discovered system has both a structurally stable strange attractor and experimentally measurable chaotic behavior. It is shown that the evolution of complex dynamics can be associated with a single parameter of a mathematical model and, due to one-to-one correspondence, to a single circuit parameter. Two-dimensional high resolution plots of the largest Lyapunov exponent and basins of attraction expressed in terms of final state energy are calculated and put into the context of the discovered third-order mathematical model and real chaotic oscillator. Both voltage- and current-mode analog chaotic oscillators are presented and verified by visualization of the typical chaotic attractor in a different fashion.
"Assessing the RAFT equilibrium constant via model systems: an EPR study"--response to a comment.
Meiser, Wibke; Buback, Michael
2012-08-14
We have presented an EPR-based approach for deducing the RAFT equilibrium constant, K(eq), of a dithiobenzoate-mediated system [Meiser, W. and Buback M. Macromol. Rapid Commun. 2011, 32, 1490]. Our value is by four orders of magnitude below K(eq) from ab initio calculations for the identical monomer-free system. Junkers et al. [Macromol. Rapid Commun. 2011, 32, 1891] claim that our EPR approach would be model dependent and our data could be equally well fitted by assuming slow addition of radicals to the RAFT agent and slow fragmentation of the so-obtained intermediate radical as well as high cross-termination rate. By identification of all side products, our EPR-based method is shown to be model independent and to provide reliable K(eq) values, which demonstrate the validity of the intermediate radical termination model. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Out-of-equilibrium correlated systems: Bipartite entanglement as a probe of thermalization
Poilblanc, Didier
2011-07-01
Thermalization plays a central role in out-of-equilibrium physics of ultracold atoms or electronic transport phenomena. On the other hand, entanglement concepts have proven to be extremely useful to investigate quantum phases of matter. Here, it is argued that bipartite entanglement measures provide key information on out-of-equilibrium states and might therefore offer stringent thermalization criteria. This is illustrated by considering a global quench in an (extended) XXZ spin-1/2 chain across its (zero-temperature) quantum critical point. A nonlocal bipartition of the chain preserving translation symmetry is proposed. The time evolution after the quench of the reduced density matrix of the half-system is computed and its associated (time-dependent) entanglement spectrum is analyzed. Generically, the corresponding entanglement entropy quickly reaches a “plateau” after a short transient regime. However, in the case of the integrable XXZ chain, the low-energy entanglement spectrum still reveals strong time fluctuations. In addition, its infinite-time average shows strong deviations from the spectrum of a Boltzmann thermal density matrix. In contrast, when the integrability of the model is broken (by small next-nearest-neighbor couplings), the entanglement spectra of the time average and thermal density matrices become remarkably similar.
Thermal energy storage systems using fluidized bed heat exchangers
Ramanathan, V.; Weast, T. E.; Ananth, K. P.
1980-01-01
The viability of using fluidized bed heat exchangers (FBHX) for thermal energy storage (TES) in applications with potential for waste heat recovery was investigated. Of the candidate applications screened, cement plant rotary kilns and steel plant electric arc furnaces were identified, via the chosen selection criteria, as having the best potential for successful use of FBHX/TES system. A computer model of the FBHX/TES systems was developed and the technical feasibility of the two selected applications was verified. Economic and tradeoff evaluations in progress for final optimization of the systems and selection of the most promising system for further concept validation are described.
Materials, Turbomachinery and Heat Exchangers for Supercritical CO2 Systems
Energy Technology Data Exchange (ETDEWEB)
Anderson, Mark; Nellis, Greg; Corradini, Michael
2012-10-19
The objective of this project is to produce the necessary data to evaluate the performance of the supercritical carbon dioxide cycle. The activities include a study of materials compatibility of various alloys at high temperatures, the heat transfer and pressure drop in compact heat exchanger units, and turbomachinery issues, primarily leakage rates through dynamic seals. This experimental work will serve as a test bed for model development and design calculations, and will help define further tests necessary to develop high-efficiency power conversion cycles for use on a variety of reactor designs, including the sodium fast reactor (SFR) and very high-temperature gas reactor (VHTR). The research will be broken into three separate tasks. The first task deals with the analysis of materials related to the high-temperature S-CO{sub 2} Brayton cycle. The most taxing materials issues with regard to the cycle are associated with the high temperatures in the reactor side heat exchanger and in the high-temperature turbine. The system could experience pressures as high as 20MPa and temperatures as high as 650°C. The second task deals with optimization of the heat exchangers required by the S-CO{sub 2} cycle; the S-CO{sub 2} flow passages in these heat exchangers are required whether the cycle is coupled with a VHTR or an SFR. At least three heat exchangers will be required: the pre-cooler before compression, the recuperator, and the heat exchanger that interfaces with the reactor coolant. Each of these heat exchangers is unique and must be optimized separately. The most challenging heat exchanger is likely the pre-cooler, as there is only about a 40°C temperature change but it operates close to the CO{sub 2} critical point, therefore inducing substantial changes in properties. The proposed research will focus on this most challenging component. The third task examines seal leakage through various dynamic seal designs under the conditions expected in the S-CO{sub 2} cycle
Work exchange between quantum systems: the spin-oscillator model.
Schröder, Heiko; Mahler, Günter
2010-02-01
With the development of quantum thermodynamics it has been shown that relaxation to thermal equilibrium and with it the concept of heat flux may emerge directly from quantum mechanics. This happens for a large class of quantum systems if embedded into another quantum environment. In this paper, we discuss the complementary question of the emergence of work flux from quantum mechanics. We introduce and discuss two different methods to assess the work source quality of a system, one based on the generalized factorization approximation, the other based on generalized definitions of work and heat. By means of those methods, we show that small quantum systems can, indeed, act as work reservoirs. We illustrate this behavior for a simple system consisting of a spin coupled to an oscillator and investigate the effects of two different interactions on the work source quality. One case will be shown to allow for a work source functionality of arbitrarily high quality.
Update on Modular Laser Launch System and Heat Exchanger Thruster
Kare, Jordin T.
2011-11-01
The heat-exchanger (HX) thruster and modular laser array provide a comparatively low-risk route to a ground-to-orbit laser launch system. Recently, the reference designs for the propulsion system, laser array, and overall launch system have evolved significantly. By combining a variable flow of dense propellant with the primary hydrogen propellant, the heat exchanger thruster can trade reduced Isp for increased thrust at liftoff, with minimal increase in tank mass. Single-mode CW fiber lasers up to 10 kW power allow a beam module to be built with off-the-shelf commercial lasers. Low-cost high-radiance laser diode arrays can deliver launch-level fluxes of 5-10 MW/m2 over tens of kilometers, sufficient to power a vehicle through the atmosphere, and high enough to hand off propulsion to a main laser array several hundred kilometers downrange. These and other enhancements enable a system design with a true single-stage vehicle in which the only component not yet demonstrated is the silicon-carbide heat exchanger itself.
Role of interface in forming non-equilibrium hcp phase by ion mixing in an immiscible Au-Co system
Yan, H F; Liu, B X
2003-01-01
In an equilibrium immiscible Au-Co system characterized by a positive heat of formation of +11 kJ mol sup - sup 1 , a non-equilibrium Au-Co phase of hcp structure was formed by 200 keV xenon ion mixing at 77 K in the Au sub 5 sub 0 Co sub 5 sub 0 multilayered films. Based on the free energy calculation, the excess interfacial free energy stored in the Au-Co multilayered films could provide adequate thermodynamic driving force for alloying between Au and Co and forming the non-equilibrium Au-Co hcp phase. Besides, the average magnetic moment per Co atom in the newly formed hcp structure was reduced by 22% of its equilibrium value, within a measuring error of 8%.
Equilibrium states of open quantum systems in the strong coupling regime.
Subaşı, Y; Fleming, C H; Taylor, J M; Hu, B L
2012-12-01
In this work we investigate the late-time steady states of open quantum systems coupled to a thermal reservoir in the strong coupling regime. In general such systems do not necessarily relax to a Boltzmann distribution if the coupling to the thermal reservoir is nonvanishing or equivalently if the relaxation time scales are finite. Using a variety of nonequilibrium formalisms valid for non-Markovian processes, we show that starting from a product state of the closed system = system+environment, with the environment in its thermal state, the open system which results from coarse graining the environment will evolve towards an equilibrium state at late times. This state can be expressed as the reduced state of the closed system thermal state at the temperature of the environment. For a linear (harmonic) system and environment, which is exactly solvable, we are able to show in a rigorous way that all multitime correlations of the open system evolve towards those of the closed system thermal state. Multitime correlations are especially relevant in the non-Markovian regime, since they cannot be generated by the dynamics of the single-time correlations. For more general systems, which cannot be exactly solved, we are able to provide a general proof that all single-time correlations of the open system evolve to those of the closed system thermal state, to first order in the relaxation rates. For the special case of a zero-temperature reservoir, we are able to explicitly construct the reduced closed system thermal state in terms of the environmental correlations.
Thermal Analysis for Ion-Exchange Column System
Energy Technology Data Exchange (ETDEWEB)
Lee, Si Y.; King, William D.
2012-12-20
Models have been developed to simulate the thermal characteristics of crystalline silicotitanate ion exchange media fully loaded with radioactive cesium either in a column configuration or distributed within a waste storage tank. This work was conducted to support the design and operation of a waste treatment process focused on treating dissolved, high-sodium salt waste solutions for the removal of specific radionuclides. The ion exchange column will be installed inside a high level waste storage tank at the Savannah River Site. After cesium loading, the ion exchange media may be transferred to the waste tank floor for interim storage. Models were used to predict temperature profiles in these areas of the system where the cesium-loaded media is expected to lead to localized regions of elevated temperature due to radiolytic decay. Normal operating conditions and accident scenarios (including loss of solution flow, inadvertent drainage, and loss of active cooling) were evaluated for the ion exchange column using bounding conditions to establish the design safety basis. The modeling results demonstrate that the baseline design using one central and four outer cooling tubes provides a highly efficient cooling mechanism for reducing the maximum column temperature. In-tank modeling results revealed that an idealized hemispherical mound shape leads to the highest tank floor temperatures. In contrast, even large volumes of CST distributed in a flat layer with a cylindrical shape do not result in significant floor heating.
Condensing Heat Exchanger Concept Developed for Space Systems
Hasan, Mohammad M.; Nayagam, Vedha
2005-01-01
The current system for moisture removal and humidity control for the space shuttles and the International Space Station uses a two-stage process. Water first condenses onto fins and is pulled through "slurper bars." These bars take in a two-phase mixture of air and water that is then separated by the rotary separator. A more efficient design would remove the water directly from the air without the need of an additional water separator downstream. For the Condensing Heat Exchanger for Space Systems (CHESS) project, researchers at the NASA Glenn Research Center in collaboration with NASA Johnson Space Center are designing a condensing heat exchanger that utilizes capillary forces to collect and remove water and that can operate in varying gravitational conditions including microgravity, lunar gravity, and Martian gravity.
Exchange Bias Effects in Iron Oxide-Based Nanoparticle Systems
Phan, Manh-Huong; Alonso, Javier; Khurshid, Hafsa; Lampen-Kelley, Paula; Chandra, Sayan; Stojak Repa, Kristen; Nemati, Zohreh; Das, Raja; Iglesias, Óscar; Srikanth, Hariharan
2016-01-01
The exploration of exchange bias (EB) on the nanoscale provides a novel approach to improving the anisotropic properties of magnetic nanoparticles for prospective applications in nanospintronics and nanomedicine. However, the physical origin of EB is not fully understood. Recent advances in chemical synthesis provide a unique opportunity to explore EB in a variety of iron oxide-based nanostructures ranging from core/shell to hollow and hybrid composite nanoparticles. Experimental and atomistic Monte Carlo studies have shed light on the roles of interface and surface spins in these nanosystems. This review paper aims to provide a thorough understanding of the EB and related phenomena in iron oxide-based nanoparticle systems, knowledge of which is essential to tune the anisotropic magnetic properties of exchange-coupled nanoparticle systems for potential applications. PMID:28335349
Sucipto, Retno Kumala Hesti; Kuswandi, Wibawa, Gede
2017-05-01
The objective of this study was to determine ternary liquid-liquid equilibrium for eugenol + tert-butanol + water system at 303.15 and 323.15K and atmospheric pressure. Using 25 mL equilibrium cell equipped jacketted water connected to water bath to maintain equilibrium temperature constant. The procedure of this experiment was conducted by inserting mixture of eugenol + tert-butanol + water system at certain composition into equilibrium cell. The solution was stirred for 4 hours and then was allowed for 20 hours in order to separate aqueous and organic phases completely. The temperature equilibrium cell of and the atmosphere pressure were recorded as equilibrium temperature and pressure for each measurenment. The equilibrium compositions of each phase were analyzed using Gas Chromatography. The experimental data obtained in this work were correlated with NRTL and UNIQUAC models with root mean square deviation between esperimental and calculated equilibrium compositions of 0.03% and 0.04% respectively.
40 CFR 63.654 - Heat exchange systems.
2010-07-01
... any one of the criteria in paragraphs (b)(1) through (2) of this section. (1) All heat exchangers that... any heat exchangers that are in organic HAP service as defined in this subpart). (c) The owner or... each heat exchanger exit line for each heat exchanger or group of heat exchangers in organic HAP...
40 CFR 63.1409 - Heat exchange system provisions.
2010-07-01
... locations where the cooling water enters and exits each heat exchanger or any combination of heat exchangers.... (iii) For samples taken at the entrance and exit of each heat exchanger or any combination of heat exchangers, the entrance is the point at which the cooling water enters the individual heat exchanger or...
Waste load equilibrium allocation: a soft path for coping with deteriorating water systems.
Yao, Liming; Xu, Jiuping; Zhang, Mengxiang; Lv, Chengwei; Li, Chaozhi
2016-08-01
Waste load allocation is always regarded as another efficient approach comparing with the technology-based approach to improve the water quality. This paper proposes a bi-level multi-objective optimization model for optimally allocating the waste load of a river basin incorporating some concerns (i) the allocation equity from the regional authority, (ii) maximal benefits from the subareas along the river, and (iii) the Stackelberg-Nash-Cournot equilibrium strategy between the upper and lower decision makers. Especially, a novel Gini coefficient for measuring the load allocation equity is defined by considering the economic level and waste water quantity. The applicability and effectiveness of the proposed model is demonstrated through a practical case based on the Tuojiang River, which is a typical basin with diversified industrial waste discharges in western China. Some operational suggestions are developed to assist the decision makers' cope with deteriorating water systems.
System and method of adjusting the equilibrium temperature of an inductively-heated susceptor
Matsen, Marc R; Negley, Mark A; Geren, William Preston
2015-02-24
A system for inductively heating a workpiece may include an induction coil, at least one susceptor face sheet, and a current controller coupled. The induction coil may be configured to conduct an alternating current and generate a magnetic field in response to the alternating current. The susceptor face sheet may be configured to have a workpiece positioned therewith. The susceptor face sheet may be formed of a ferromagnetic alloy having a Curie temperature and being inductively heatable to an equilibrium temperature approaching the Curie temperature in response to the magnetic field. The current controller may be coupled to the induction coil and may be configured to adjust the alternating current in a manner causing a change in at least one heating parameter of the susceptor face sheet.
Modeling Of Proton Exchange Membrane Fuel Cell Systems
DEFF Research Database (Denmark)
Nielsen, Mads Pagh
The objective of this doctoral thesis was to develop reliable steady-state and transient component models suitable to asses-, develop- and optimize proton exchange membrane (PEM) fuel cell systems. Several components in PEM fuel cell systems were characterized and modeled. The developed component...... cell systems. Consequences of indirectly fueling PEM stacks with hydrocarbons using reforming technology were investigated using a PEM stack model including CO poisoning kinetics and a transient Simulink steam reforming system model. Aspects regarding the optimization of PEM fuel cell systems......- and system models match experimental data from the literature. However, limited data were available for verification so further work is necessary to confirm detailed aspects of the models. It is nonetheless expected that the developed models will be useful for system modeling and optimization of PEM fuel...
Dron, Julien; Dodi, Alain
2011-06-15
The removal of chloride, nitrate and sulfate ions from aqueous solutions by a macroporous resin is studied through the ion exchange systems OH(-)/Cl(-), OH(-)/NO(3)(-), OH(-)/SO(4)(2-), and HCO(3)(-)/Cl(-), Cl(-)/NO(3)(-), Cl(-)/SO(4)(2-). They are investigated by means of Langmuir, Freundlich, Dubinin-Radushkevitch (D-R) and Dubinin-Astakhov (D-A) single-component adsorption isotherms. The sorption parameters and the fitting of the models are determined by nonlinear regression and discussed. The Langmuir model provides a fair estimation of the sorption capacity whatever the system under study, on the contrary to Freundlich and D-R models. The adsorption energies deduced from Dubinin and Langmuir isotherms are in good agreement, and the surface parameter of the D-A isotherm appears consistent. All models agree on the order of affinity OH(-)models provide the best fit to the experimental points, indicating that the micropore volume filling theory is the best representation of the ion exchange processes under study among other adsorption isotherms. The nonlinear regression results are also compared with linear regressions. While the parameter values are not affected, the evaluation of the best fitting model is biased by linearization. Copyright © 2011 Elsevier B.V. All rights reserved.
Optimizing the Heat Exchanger Network of a Steam Reforming System
DEFF Research Database (Denmark)
Nielsen, Mads Pagh; Korsgaard, Anders Risum; Kær, Søren Knudsen
2004-01-01
gas steam reformer along with gas purification reactors to generate clean hydrogen suited for a PEM stack. The temperatures in the various reactors in the fuel processing system vary from around 1000°C to the stack temperature at 80°C. Furthermore, external heating must be supplied to the endothermic...... steam reforming reaction and steam must be generated. The dependence of the temperature profiles on conversion in shift reactors for gas purification is also significant. The optimum heat integration in the system is thus imperative in order to minimize the need for hot and cold utilities. A rigorous 1D......Proton Exchange Membrane (PEM) based combined heat and power production systems are highly integrated energy systems. They may include a hydrogen production system and fuel cell stacks along with post combustion units optionally coupled with gas turbines. The considered system is based on a natural...
Standards, Data Exchange and Intellectual Property Rights in Systems Biology
DEFF Research Database (Denmark)
van Zimmeren, Esther; Rutz, Berthold; Minssen, Timo
2016-01-01
assets to be formatted and described in standard ways to enable exchange and reuse of high quality data. This allows a more effective utilisation of the enormous potential that rests in “big data” analysis. Finally, SysBio is often closely linked to or provides the foundation for Synthetic Biology (Syn...... we provided a number of recommendations for a variety of stakeholders. The current article offers some deeper reflections about the interface between IPRs, standards and data exchange in Systems Biology resulting from an Expert Meeting funded by another ERA-Net, ERASysAPP. The meeting brought...... and qualitative data on biological processes and activities in much greater volumes, velocity, variety and veracity. The skilful integration of multiple heterogeneous data sets allows scientists to model and predict biological processes. SysBio’s interdisciplinary nature requires data, models and other research...
Wiesel, A; Schmidt-Traub, H; Lenz, J; Strube, J
2003-07-18
A theoretical framework for the ion-exchange behaviour of bioactive substances in non-linear ion-exchange chromatogaphy is described. The aim of the study was the creation of a model basis to support a process design for production-scale ion-exchange chromatography. The theory can be applied to a whole variety of biological substances, such as amino acids, polysaccharides, peptides and proteins and either isocratic or gradient elution can be carried out. The influence of the eluent concentration on the ion-exchange as well as on the characteristic charge was considered. Experimental measurements showed a strong non-linear ion-exchange equilibrium with a transition from a Langmuir-type to a sigmoidal isotherm at higher eluent concentrations. Hereby, the compound binds to the surface though it is not ionic. Therefore, the model considered the possibility of ion-exchange as well as adsorption. A simplified distribution of the counter-ions based on the Gouy-Chapman theory with a discrete distribution of the counter-ions was used. The theory was extended by a selectivity in the double layer to allow specific adsorption. Calculations of adsorption-elution cycles showed, in agreement with the experimental observations, the development of non-linear elution profiles with a desorption fronting. As a result, the column loading and the eluent concentration were varied. The effect of contaminants, in this case sodium ions, was investigated and included in the model. Finally, the model was extended to multicomponent systems to investigate the effect of side components on the retention behaviour. The development of the characteristic elution profiles and the effect of the column loading on the separation are discussed. Calculated concentration profiles along the column at discrete time steps were used to reveal the influence of side components and the underlying separation mechanism. The simulations provided a new insight into the phenomena involved in biochromatography and make
Conductivity of strongly pumped superconductors. An electron-phonon system far from equilibrium
Energy Technology Data Exchange (ETDEWEB)
Krull, Holger
2015-01-29
The study of nonequilibrium physics is of great interest, because one can capture novel phenomena and properties which are hidden at equilibrium, e.g., one can study relaxation processes. A common way to study the nonequilibrium dynamics of a sample is a pump-probe experiment. In a pump probe experiment an intense laser pulse, the so called pump pulse, excites the sample and takes it out of equilibrium. After a certain delay time a second pulse, the probe pulse, measures the actual state of the sample. In this thesis, we theoretically study the pump-probe response of superconductors. On the one hand we are interest in the effect of a pump pulse and on the other hand we want to provide the pump-probe response, such that experimental measurement can be easily interpreted. In order to do this, we use the density matrix formalism to compute the pump-probe response of the system. In the density matrix formalism equations of motion are set up for expectation values of interest. In order to study the dynamics induced by a pump pulse, we compute the temporal evolution of the quasiparticle densities and the mean phonon amplitude. We find that the induced dynamics of the system depends on characteristics of the pump pulse. For short pulses, the system is pushed into the nonadiabatic regime. In this regime, the order parameter is lowered during the pump pulse and shows a 1/(√(t))-decaying oscillation afterwards. In addition, coherent phonons are generated, which is resonantly enhanced if the frequency of the order parameter oscillation is equal to the phonon frequency. For long pulses, the system is pushed into the adiabatic regime. In this regime, the order parameter is lowered during the pulse and remains almost constant afterwards. Further, there is almost no generation of coherent phonons. For the pump-probe response we compute the conductivity induced by the probe pulse. The conductivity is a typical observable in real pump-probe experiments. Hence, it is possible to
Fluid-like entropy and equilibrium statistical mechanics of self-gravitating systems
Kang, Dong-Biao; He, Ping
2011-09-01
The statistical mechanics of self-gravitating systems has not been well understood, and still remains an open question so far. In a previous study by Kang & He, we showed that the fluid approximation may give a clue to investigate this problem further. In fact, there are indeed many dynamical similarities between self-gravitating and fluid systems. Based on a fluid-like entropy, that work explained successfully the outer density profiles of dark matter haloes, but there remain some drawbacks with the calculation concerning the extremizing process of the entropy. In the current paper, with the improved extremizing calculation - including an additional differential constraint of dynamical equilibrium and without any other assumptions, we confirm that statistical-mechanical methods can give a density profile with finite mass and finite energy. Moreover, this density profile is also consistent with the observational surface brightness of the elliptical galaxy NGC 3379. In our methods, the density profile is derived from the equation of state, which is obtained from the entropy principle but does not correspond to the maximum entropy of the system. Finally, we suggest an alternative entropy form, a hybrid of Boltzmann-Gibbs and Tsallis entropy, whose global maximum may give rise to this equation of state.
Brownian motion in non-equilibrium systems and the Ornstein-Uhlenbeck stochastic process.
Donado, F; Moctezuma, R E; López-Flores, L; Medina-Noyola, M; Arauz-Lara, J L
2017-10-03
The Ornstein-Uhlenbeck stochastic process is an exact mathematical model providing accurate representations of many real dynamic processes in systems in a stationary state. When applied to the description of random motion of particles such as that of Brownian particles, it provides exact predictions coinciding with those of the Langevin equation but not restricted to systems in thermal equilibrium but only conditioned to be stationary. Here, we investigate experimentally single particle motion in a two-dimensional granular system in a stationary state, consisting of 1 mm stainless balls on a plane circular surface. The motion of the particles is produced by an alternating magnetic field applied perpendicular to the surface of the container. The mean square displacement of the particles is measured for a range of low concentrations and it is found that following an appropriate scaling of length and time, the short-time experimental curves conform a master curve covering the range of particle motion from ballistic to diffusive in accordance with the description of the Ornstein-Uhlenbeck model.
Energy Technology Data Exchange (ETDEWEB)
Koerting, V., E-mail: koerting@nbi.d [Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Niels Bohr Institute, Universitetsparken, DK-2100 Copenhagen (Denmark); The Niels Bohr International Academy, The Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen (Denmark); Fritsch, P. [Physics Department, Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Ludwig-Maximilians-Universitaet, Theresienstrasse 37, 80333 Munich (Germany); Kehrein, S., E-mail: stefan.kehrein@physik.lmu.d [Physics Department, Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Ludwig-Maximilians-Universitaet, Theresienstrasse 37, 80333 Munich (Germany)
2011-05-15
Since the experimental realization of Kondo physics in quantum dots, its far-from-equilibrium properties have generated considerable theoretical interest. This is due to the interesting interplay of non-equilibrium physics and correlation effects in this model, which has now been analyzed using several new theoretical methods that generalize renormalization techniques to non-equilibrium situations. While very good agreement between these methods has been found for the spin-1/2 Kondo model, it is desirable to have a better understanding of their applicability for more complicated impurity models. In this paper the differences and commons between two such approaches, namely the flow equation method out of equilibrium and the frequency-dependent poor man's scaling approach are presented for the non-equilibrium double quantum dot system. This will turn out to be a particularly suitable testing ground while being experimentally interesting in its own right. An outlook is given on the quantum critical behavior of the double quantum dot system and its accessibility with the two methods.
A Freezable Heat Exchanger for Space Suit Radiator Systems
Nabity, James A.; Mason, Georgia R.; Copeland, Robert J.; Trevino, Luis a.
2008-01-01
During an ExtraVehicular Activity (EVA), both the heat generated by the astronaut s metabolism and that produced by the Portable Life Support System (PLSS) must be rejected to space. The heat sources include the heat of adsorption of metabolic CO2, the heat of condensation of water, the heat removed from the body by the liquid cooling garment and the load from the electrical components. Although the sublimator hardware to reject this load weighs only 1.58 kg (3.48 lbm), an additional 3.6 kg (8 lbm) of water are loaded into the unit, most of which is sublimated and lost to space, thus becoming the single largest expendable during an eight-hour EVA. Using a radiator to reject heat from the astronaut during an EVA can reduce the amount of expendable water consumed in the sublimator. Radiators have no moving parts and are thus highly reliable. Past freezable radiators have been too heavy, but the weight can be greatly reduced by placing a small and freeze tolerant heat exchanger between the astronaut and radiator, instead of making the very large radiator freeze tolerant. Therefore, the key technological innovation to improve space suit radiator performance was the development of a lightweight and freezable heat exchanger that accommodates the variable heat load generated by the astronaut. Herein, we present the heat transfer performance of a newly designed heat exchanger that endured several freeze / thaw cycles without any apparent damage. The heat exchanger was also able to continuously turn down or turn up the heat rejection to follow the variable load.
A microprocessor-based system for measurement of gas exchange.
Jaffe, M B; Frick, G; Wilson, D; Johnston, M; Reid, H; Foster, S; Norton, A C
1984-10-01
The basic physical measurements for determining gas exchange are difficult to make accurately even in a well-equipped, human-performance laboratory with experienced personnel. A fully automated system has been developed to achieve the accuracy of standard laboratory measurements. The application of this instrument extends from critical care to stress-testing. Real-time, multitasking software integrates the data collected from several transducers and analyzers and calculates up to several dozen physiological variables, which are range-checked for reasonableness. The operator is provided with user-friendly means to tailor the data-reporting and- collection functions of the system to his own needs and requirements. Because the instrument is controlled by software, the functions of calibration, measurement, timing, reporting, plotting, and data quality assurance are highly cost-effective. Extensive use of formal test procedures permits verifying all systems and data reliability; it also assures meeting the desired specifications. The ease of operation and high-quality results inherent in this system make it unsurpassed in gas-exchange measurements.
Chemical potential in active systems: predicting phase equilibrium from bulk equations of state?
Paliwal, Siddharth; Rodenburg, Jeroen; van Roij, René; Dijkstra, Marjolein
2018-01-01
We derive a microscopic expression for a quantity μ that plays the role of chemical potential of active Brownian particles (ABPs) in a steady state in the absence of vortices. We show that μ consists of (i) an intrinsic chemical potential similar to passive systems, which depends on density and self-propulsion speed, but not on the external potential, (ii) the external potential, and (iii) a newly derived one-body swim potential due to the activity of the particles. Our simulations on ABPs show good agreement with our Fokker–Planck calculations, and confirm that μ (z) is spatially constant for several inhomogeneous active fluids in their steady states in a planar geometry. Finally, we show that phase coexistence of ABPs with a planar interface satisfies not only mechanical but also diffusive equilibrium. The coexistence can be well-described by equating the bulk chemical potential and bulk pressure obtained from bulk simulations for systems with low activity but requires explicit evaluation of the interfacial contributions at high activity.
Mean first-passage times for systems driven by equilibrium persistent-periodic dichotomous noise
Energy Technology Data Exchange (ETDEWEB)
Porra, J.M.; Lindenberg, K. [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0340 (United States)
1995-07-01
In a recent paper, [J. M. Porra, J. Masoliver, and K. Lindenberg, Phys. Rev. E 48, 951 (1993)], we derived the equations for the mean first-passage time for systems driven by the coin-toss square wave, a particular type of dichotomous noisy signal, to reach either one of two boundaries. The coin-toss square wave, which we here call periodic-persistent dichotomous noise, is a random signal that can only change its value at specified time points, where it changes its value with probability {ital q} or retains its previous value with probability {ital p}=1{minus}{ital q}. These time points occur periodically at time intervals {tau}. Here we consider the stationary version of this signal, that is, ``equilibrium`` periodic-persistent noise. We show that the mean first-passage time for systems driven by this stationary noise does not show either the discontinuities or the oscillations found in the case of nonstationary noise. We also discuss the existence of discontinuities in the mean first-passage time for random one-dimensional stochastic maps.
Assessing the RAFT equilibrium constant via model systems: an EPR study.
Meiser, Wibke; Buback, Michael
2011-09-15
Reversible addition-fragmentation chain transfer (RAFT) equilibrium constants, K(eq), for the model system cyano-iso-propyl dithiobenzoate (CPDB) - cyano-iso-propyl radical (CIP) have been deduced via electron paramagnetic resonance (EPR) spectroscopy. The CIP species is produced by thermal decomposition of azobis-iso-butyronitrile (AIBN). In solution of toluene at 70 °C, K(eq) has been determined to be (9 ± 1) L · mol(-1). Measurement of K(eq) = k(ad)/k(β) between 60 and 100 °C yields ΔE(a) = (-28 ± 4) kJ · mol(-1) as the difference in the activation energies of k(ad) and k(β). The data measured on the model system are indicative of fast fragmentation of the intermediate radical produced by addition of CIP to CPDB. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Energy Technology Data Exchange (ETDEWEB)
Domanska, Urszula, E-mail: ula@ch.pw.edu.pl [Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland); Thermodynamic Research Unit, School of Chemical Engineering, University of KwaZulu-Natal, Howard College Campus, King George V Avenue, Durban 4001 (South Africa); Krolikowski, Marek [Department of Physical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw (Poland)
2011-10-15
Highlights: > Synthesis, DSC, and measurements of phase equilibrium of N-hexyl-3-methylpyridinium tosylate. > Solvents used: water, alcohols, benzene, alkylbenzenes, and aliphatic hydrocarbons. > Correlation with UNIQUAC, Wilson and NRTL models. > Comparison with different tosylate-based ILs. - Abstract: The (solid + liquid) phase equilibrium (SLE) and (liquid + liquid) phase equilibrium (LLE) for the binary systems ionic liquid (IL) N-hexyl-3-methylpyridinium tosylate (p-toluenesulfonate), {l_brace}([HM{sup 3}Py][TOS] + water, or an alcohol (1-butanol, or 1-hexanol, or 1-octanol, or 1-decanol), or an aromatic hydrocarbon (benzene, toluene, or ethylbenzene, or propylbenzene), or an alkane (n-hexane, n-heptane, n-octane){r_brace} have been determined at ambient pressure using a dynamic method. Simple eutectic systems with complete miscibility in the liquid phase were observed for the systems involving water and alcohols. The phase equilibrium diagrams of IL and aromatic or aliphatic hydrocarbons exhibit eutectic systems with immiscibility in the liquid phase with an upper critical solution temperature as for most of the ILs. The correlation of the experimental data has been carried out using the UNIQUAC, Wilson and the non-random two liquid (NRTL) correlation equations. The results reported here have been compared with analogous phase diagrams reported by our group previously for systems containing the tosylate-based ILs.
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...
Universality classes far from equilibrium. From heavy-ion collisions to superfluid Bose systems
Energy Technology Data Exchange (ETDEWEB)
Boguslavski, Kirill
2016-07-27
Quantum many-body systems far from equilibrium can approach a nonthermal fixed point during their real-time evolution. One example is scalar field theory, which occurs in models of cosmological inflation, and similar examples are found for non-Abelian plasmas relevant for heavy-ion collisions and for ultracold Bose gases. Investigating nonthermal fixed points of different microscopic theories, we present two novel universality classes that provide links between these systems. One of them involves nonrelativistic, N-component relativistic and expanding scalar systems. It occurs in the deep infrared regime of very high occupancies and is governed by a self-similar evolution. Its nonequilibrium dynamics leads to the formation of a Bose-Einstein condensate. The scaling properties of this region can be described by a vertex-resummed kinetic theory that is based on a systematic large-N expansion at next-to-leading order. The other novel universality class encompasses scalar field theories and non-Abelian plasmas in a longitudinally expanding background and corresponds to an early dynamical stage of heavy-ion collisions in the high-energy limit. We show that these systems share the same self-similar scaling properties for a wide range of momenta in a limit where particles are weakly coupled but their occupancy is high. Both universality classes are found in separate momentum regions in a longitudinally expanding N-component scalar field theory. We argue that the important role of the infrared dynamics ensures that key features of our results for scalar and gauge theories cannot be reproduced consistently in conventional kinetic theory frameworks. Moreover, the observed universality connects different physics disciplines from heavy-ion collisions to ultracold atoms, making a remarkable link between the world's hottest and coldest matter.
Reactivation System for Proton-Exchange Membrane Fuel-Cells
Directory of Open Access Journals (Sweden)
Roberto Giral
2012-07-01
Full Text Available In recent years, Proton-Exchange Membrane Fuel Cells (PEMFCs have been the focus of very intensive researches. Manufacturers of these alternative power sources propose a rejuvenation sequence after the FC has been operating at high power for a certain period of time. These rejuvenation methods could be not appropriate for the reactivation of the FC when it has been out of operation for a long period of time or after it has been repaired. Since the developed reactivation system monitors temperature, current, and the cell voltages of the stack, it could be also useful for the diagnostic and repairing processes. The limited number of published contributions suggests that systems developing reactivation techniques are an open research field. In this paper, an automated system for reactivating PEMFCs and results of experimental testing are presented.
Out-of-equilibrium Correlated Systems : Bipartite Entanglement as a Probe of Thermalization
Poilblanc, Didier
2010-01-01
Thermalization play a central role in out-of-equilibrium physics of ultracold atoms or electronic transport phenomena. On the other hand, entanglement concepts have proven to be extremely useful to investigate quantum phases of matter. Here, it is argued that **bipartite** entanglement measures provide key information on out-of-equilibrium states and might therefore offer stringent thermalization criteria. This is illustrated by considering a global quench in an (extended) XXZ spin-1/2 chain ...
Dynamics of a spin-1 Ising system in the neighborhood of equilibrium states
Erdem, R.ıza; Keskin, Mustafa
2001-08-01
The dynamics of a spin-1 Ising system containing biquadratic interactions near equilibrium states is formulated by the method of thermodynamics of irreversible processes. From the expression for the entropy production, generalized forces and fluxes are determined. The kinetic equations are obtained by introducing kinetic coefficients that satisfy the Onsager relation. By solving these equations a set of relaxation times is calculated and examined for temperatures near the phase transition temperatures, with the result that one of the relaxation times approaches infinity near the second-order phase transition temperature on either side, whereas it is sharply cusped at the first-order phase transition temperature. On the other hand, the other relaxation time has a cusp at the second-order phase transition temperature but displays a different behavior at the first-order phase transition, just a jump discontinuity. The behavior of both relaxation times is also investigated at the tricritical point. Moreover, the phase transition behaviors of the relaxation times are also obtained analytically via the critical exponents. Results are compared with conventional kinetic theory in the random-phase or generalized molecular-field approximation and a very good overall agreement is found.
A Spacebased Ocean Surface Exchange Data Analysis System
Tang, Wenqing; Liu, W. Timothy
2000-01-01
Emerging technologies have provided unprecedented opportunities to transform information into knowledge and disseminate them in a much faster, cheaper, and userfriendly mode. We have set up a system to produce and disseminate high level (gridded) ocean surface wind data from the NASA Scatterometer and European Remote Sensing missions. The data system is being expanded to produce real-time gridded ocean surface winds from an improved sensor SeaWinds on the Quikscat Mission. The wind field will be combined with hydrologic parameters from the Tropical Rain Measuring Mission to monitor evolving weather systems and natural hazard in real time. It will form the basis for spacebased Ocean Surface Exchange Data Analysis System (SOSEDAS) which will include the production of ocean surface momentum, heat, and water fluxes needed for interdisciplinary studies of ocean-atmosphere interaction. Various commercial or non-commercial software tools have been compared and selected in terms of their ability in database management, remote data accessing, graphical interface, data quality, storage needs and transfer speed, etc. Issues regarding system security and user authentication, distributed data archiving and accessing, strategy to compress large-volume geophysical and satellite data/image. and increasing transferring speed are being addressed. A simple and easy way to access information and derive knowledge from spacebased data of multiple missions is being provided. The evolving 'knowledge system' will provide relevant infrastructure to address Earth System Science, make inroads in educating an informed populace, and illuminate decision and policy making.
Advanced integrated solvent extraction and ion exchange systems
Energy Technology Data Exchange (ETDEWEB)
Horwitz, P. [Argonne National Lab., IL (United States)
1996-10-01
Advanced integrated solvent extraction (SX) and ion exchange (IX) systems are a series of novel SX and IX processes that extract and recover uranium and transuranics (TRUs) (neptunium, plutonium, americium) and fission products {sup 90}Sr, {sup 99}Tc, and {sup 137}Cs from acidic high-level liquid waste and that sorb and recover {sup 90}Sr, {sup 99}Tc, and {sup 137}Cs from alkaline supernatant high-level waste. Each system is based on the use of new selective liquid extractants or chromatographic materials. The purpose of the integrated SX and IX processes is to minimize the quantity of waste that must be vitrified and buried in a deep geologic repository by producing raffinates (from SX) and effluent streams (from IX) that will meet the specifications of Class A low-level waste.
Kleidon, A.
2010-01-01
The Earth system is remarkably different from its planetary neighbours in that it shows pronounced, strong global cycling of matter. These global cycles result in the maintenance of a unique thermodynamic state of the Earth's atmosphere which is far from thermodynamic equilibrium (TE). Here, I provide a simple introduction of the thermodynamic basis to understand why Earth system processes operate so far away from TE. I use a simple toy model to illustrate the application of non-equilibrium thermodynamics and to classify applications of the proposed principle of maximum entropy production (MEP) to such processes into three different cases of contrasting flexibility in the boundary conditions. I then provide a brief overview of the different processes within the Earth system that produce entropy, review actual examples of MEP in environmental and ecological systems, and discuss the role of interactions among dissipative processes in making boundary conditions more flexible. I close with a brief summary and conclusion. PMID:20368248
Energy Technology Data Exchange (ETDEWEB)
Miroshnichenko, A.A.
1983-07-20
The selection of efficient separating agents for the extractive fractionation of aliphatic-aromatic hydrocarbon systems has fundamental importance in technology of preparing pure aromatic hydrocarbons. It has been shown previously that N-methylpyrrolidone (NMP) can be used as an efficient separating agent for paraffin-aromatic hydrocarbon, naphthene-aromatic hydrocarbon, or olefin-aromatic hydrocarbon systems. It was previously shown that the presence of water in the NMP increases its selectivity in the heptane-benzene system. However, the limited number of systems studied which contain heptane does not allow one to make a judgment about the relative volatility of paraffins, naphthenes, olefins, and benzene in mixtures with NMP containing water. Moreover, the complexity of the indicated systems causes definite difficulties in the experimental study of the isobaric liquid-vapor equilbrium for determining the relative volatility ..cap alpha../sub i-j/ of nonaromatic hydrocarbons, i, and benzene, j, as a function of the concentration of an extractant containing water, X/sub r/. The author has previously made studies of methods of calculating liquid-vapor equilibrium in the analogous systems with anhydrous NMP from a limited amount of information about liquid-vapor equilibrium. Therefore the objective of this work was to perform analytical calculations and an experimental check of liquid-vapor equilibrium in systems which included paraffins, naphthenes, olefins, benzene, NMP, and water.
Gregory, R.T.; Criss, R.E.; Taylor, H.P.
1989-01-01
The systematics of stable-isotope exchange between minerals and fluids are examined in the context of modal mineralogical variations and mass-balance considerations, both in closed and in open systems. On mineral-pair ??18O plots, samples from terranes that have exchanged with large amounts of fluid typically map out steep positively-sloped non-equilibrium arrays. Analytical models are derived to explain these effects; these models allow for different exchange rates between the various minerals and the external fluids, as well as different fluid fluxes. The steep arrays are adequately modelled by calculated isochron lines that involve the whole family of possible exchange trajectories. These isochrons have initially-steep near-vertical positive slopes that rotate toward a 45?? equilibrium slope as the exchange process proceeds to completion. The actual data-point array is thus analogous to the hand of an "isotopic clock" that measures the duration of the hydrothermal episode. The dimensionless ratio of the volumetric fluid flux to the kinetic rate parameter ( u k) determines the shape of each individual exchange trajectory. In a fluid-buffered system ( u k ??? 1), the solutions to the equations: (1) are independent of the mole fractions of the solid phases; (2) correspond to Taylor's open-system water/rock equation; and (3) yield straight-line isochrons that have slopes that approach 1 f, where f is the fraction reacted of the more sluggishly exchanging mineral. The isochrons for this simple exchange model are closely congruent with the isochrons calculated for all of the more complex models, thereby simplifying the application of theory to actual hydrothermal systems in nature. In all of the models an order of magnitude of time (in units of kt) separates steep non-equilibrium arrays (e.g., slope ??? 10) from arrays approaching an equilibrium slope of unity on a ??-?? diagram. Because we know the approximate lifetimes of many hydrothermal systems from geologic and
Feder-Bubis, Paula; Chinitz, David
2010-08-01
Israel's enactment of national health insurance was clearly a breakthrough. However, other aspects of reform that were supposed to be implemented simultaneously were stymied, in particular, the conversion of government hospitals to independent trusts and removing the Ministry of Health from the direct provision of services such as mental health and long-term care. This article explores how punctuated equilibrium and path dependency coexist in the Israeli case. In doing so, it examines the relevance of concepts provided by various theories of social and institutional change. Aside from path dependency and punctuated equilibrium, we discuss other notions derived from related theories, such as political leadership and the role of ideas. Applying these theories to the Israeli case helps better understand the coexistence of punctuated equilibrium and path dependency.
Modelling Thomson scattering for systems with non-equilibrium electron distributions
Directory of Open Access Journals (Sweden)
Chapman D.A.
2013-11-01
Full Text Available We investigate the effect of non-equilibrium electron distributions in the analysis of Thomson scattering for a range of conditions of interest to inertial confinement fusion experiments. Firstly, a generalised one-component model based on quantum statistical theory is given in the random phase approximation (RPA. The Chihara expression for electron-ion plasmas is then adapted to include the new non-equilibrium electron physics. The theoretical scattering spectra for both diffuse and dense plasmas in which non-equilibrium electron distributions are expected to arise are considered. We find that such distributions strongly influence the spectra and are hence an important consideration for accurately determining the plasma conditions.
Fabrication of Flat Plate Solar Geyser with Flat Grooved Heat Exchanger Having Special Exit System
Malik, Muhammad Suleman; Malik, Muhammad Arsalan; Shah, Haseeb Ali; Khan Afridi, Adnan Anwar; Asif, Muhammad
2017-01-01
International audience; The main objective of this paper is to introduce the concept of novel flat plate solar geyser with integrated heat exchanger and open loop passive system.The heat exchanger acts both as collector for solar radiations and as a heat exchanger its self for cold water beneath it. Contrary to the conventional flat plate solar collectors, water is in direct contact with the collector or flat grooved heat exchanger. A safety control box is installed to minimize hydraulic pres...
Fundamentals for magnetic patterning by ion bombardment of exchange bias layer systems
Ehresmann, A.; Engel, D.; Weis, T.; Schindler, A.; Junk, D.; Schmalhorst, J.; Höink, V.; Sacher, M. D.; Reiss, G.
2006-01-01
In the present paper we investigate whether the ion bombardment induced magnetic modifications in exchange biased bilayers are stable in time, whether the direction of the exchange bias can be set to any arbitrary (in-plane) direction by the ion bombardment and whether the exchange bias field can be changed in successive bombardment steps. These three fundamental characteristics are prerequisites for ion bombardment used for an efficient, practical, and stable magnetic patterning of exchange biased layer systems.
Wang, Zhijian; Xu, Bin; Zhejiang Collaboration
2011-03-01
In social science, laboratory experiment with human subjects' interaction is a standard test-bed for studying social processes in micro level. Usually, as in physics, the processes near equilibrium are suggested as stochastic processes with time-reversal symmetry (TRS). To the best of our knowledge, near equilibrium, the breaking time symmetry, as well as the existence of robust time anti-symmetry processes, has not been reported clearly in experimental economics till now. By employing Markov transition method to analysis the data from human subject 2x2 Games with wide parameters and mixed Nash equilibrium, we study the time symmetry of the social interaction process near Nash equilibrium. We find that, the time symmetry is broken, and there exists a robust time anti-symmetry processes. We also report the weight of the time anti-symmetry processes in the total processes of each the games. Evidences in laboratory marketing experiments, at the same time, are provided as one-dimension cases. In these cases, time anti-symmetry cycles can also be captured. The proposition of time anti-symmetry processes is small, but the cycles are distinguishable.
Gelin, M F; Kosov, D S
2008-07-01
We present a unified and simple method for deriving work theorems for classical and quantum Hamiltonian systems, both under equilibrium conditions and in a steady state. Throughout the paper, we adopt the partitioning of the total Hamiltonian into the system part, the bath part, and their coupling. We rederive many equalities which are available in the literature and obtain a number of new equalities for nonequilibrium classical and quantum systems. Our results can be useful for determining partition functions and (generalized) free energies through simulations or measurements performed on nonequilibrium systems.
Energy Technology Data Exchange (ETDEWEB)
Michielin, Eliane M.Z.; Rosso, Sibele R. [EQA/UFSC, Chemical and Food Engineering Department, Federal University of Santa Catarina, C.P. 476, CEP 88040-900, Florianopolis, SC (Brazil); Franceschi, Elton; Borges, Gustavo R.; Corazza, Marcos L.; Oliveira, J. Vladimir [Department of Food Engineering, URI - Campus de Erechim, Av. Sete de Setembro, 1621, Erechim, RS, 99700-000 (Brazil); Ferreira, Sandra R.S. [EQA/UFSC, Chemical and Food Engineering Department, Federal University of Santa Catarina, C.P. 476, CEP 88040-900, Florianopolis, SC (Brazil)], E-mail: sandra@enq.ufsc.br
2009-01-15
The aim of this work is to report phase equilibrium data for the binary systems (CO{sub 2} + {alpha}-humulene) and (CO{sub 2} + trans-caryophyllene), and for the ternary system (CO{sub 2} + {alpha}-humulene + trans-caryophyllene). Results from literature show that {alpha}-humulene and trans-caryophyllene are the main compounds responsible for the anti-inflammatory and anti-allergic characteristics attributed to the medicinal plant Cordia verbenacea D.C., hence giving importance to the phase behaviour investigation performed in this work. Phase equilibrium experiments were performed in a high-pressure, variable-volume view cell over the temperature range of T = (303 to 343) K and pressures up to 20 MPa. (Liquid + liquid) and (vapour + liquid + liquid) equilibrium were observed at T = 303 K, while (vapour + liquid) phase transitions were verified to occur from T = (313 to 343) K, for all systems studied. Thermodynamic modelling was performed using the Peng-Robinson equation of state and the classical quadratic mixing rules, with a satisfactory agreement between experimental and calculated values.
Compact Water Vapor Exchanger for Regenerative Life Support Systems
Izenson, Michael G.; Chen, Weibo; Anderson, Molly; Hodgson, Edward
2012-01-01
Thermal and environmental control systems for future exploration spacecraft must meet challenging requirements for efficient operation and conservation of resources. Regenerative CO2 removal systems are attractive for these missions because they do not use consumable CO2 absorbers. However, these systems also absorb and vent water to space along with carbon dioxide. This paper describes an innovative device designed to minimize water lost from regenerative CO2 control systems. Design studies and proof-of-concept testing have shown the feasibility of a compact, efficient membrane water vapor exchanger (WVX) that will conserve water while meeting challenging requirements for operation on future spacecraft. Compared to conventional WVX designs, the innovative membrane WVX described here has the potential for high water recovery efficiency, compact size, and very low pressure losses. The key innovation is a method for maintaining highly uniform flow channels in a WVX core built from water-permeable membranes. The proof-of-concept WVX incorporates all the key design features of a prototypical unit, except that it is relatively small scale (1/23 relative to a unit sized for a crew of six) and some components were fabricated using non-prototypical methods. The proof-of-concept WVX achieved over 90% water recovery efficiency in a compact core in good agreement with analysis models. Furthermore the overall pressure drop is very small (less than 0.5 in. H2O, total for both flow streams) and meets requirements for service in environmental control and life support systems on future spacecraft. These results show that the WVX provides very uniform flow through flow channels for both the humid and dry streams. Measurements also show that CO2 diffusion through the water-permeable membranes will have negligible effect on the CO2 partial pressure in the spacecraft atmosphere.
Fault tolerance control for proton exchange membrane fuel cell systems
Wu, Xiaojuan; Zhou, Boyang
2016-08-01
Fault diagnosis and controller design are two important aspects to improve proton exchange membrane fuel cell (PEMFC) system durability. However, the two tasks are often separately performed. For example, many pressure and voltage controllers have been successfully built. However, these controllers are designed based on the normal operation of PEMFC. When PEMFC faces problems such as flooding or membrane drying, a controller with a specific design must be used. This paper proposes a unique scheme that simultaneously performs fault diagnosis and tolerance control for the PEMFC system. The proposed control strategy consists of a fault diagnosis, a reconfiguration mechanism and adjustable controllers. Using a back-propagation neural network, a model-based fault detection method is employed to detect the PEMFC current fault type (flooding, membrane drying or normal). According to the diagnosis results, the reconfiguration mechanism determines which backup controllers to be selected. Three nonlinear controllers based on feedback linearization approaches are respectively built to adjust the voltage and pressure difference in the case of normal, membrane drying and flooding conditions. The simulation results illustrate that the proposed fault tolerance control strategy can track the voltage and keep the pressure difference at desired levels in faulty conditions.
Quaternary liquid-liquid equilibrium studies on hydrocarbon-solvent systems
Energy Technology Data Exchange (ETDEWEB)
Naithani, J.; Khanna, M.K.; Nanoti, S.M.; Rawat, B.S. (Indian Inst. of Petroleum, Dehra Dun 248005 (IN))
1992-01-01
This paper reports that quaternary equilibrium tie-line data have been determined at 60{degrees}C for the model hydrocarbon mixtures of naphtha and kerosene with sulfolane and triethylene glycol solvents. The study was carried out in order to understand the mechanism of simultaneous extraction of aromatics from naphtha and kerosene feedstocks. Benzene-heptane and 1-methylnaphthalene-dodecane model mixtures were chosen as feeds representing naphtha and kerosene cuts, respectively. The liquid-liquid equilibrium data so obtained have been predicted by the UNIFAC group contribution model. Group interaction parameters for groups which best represent triethylene glycol molecule were also calculated from the data available with the authors for those not available in the literature.
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...
Energy Technology Data Exchange (ETDEWEB)
Pruschke, Th., E-mail: pruschke@theorie.physik.uni-goettingen.d [Insitute for Theoretical Physics, University of Goettingen, Friedrich-Hund-Platz 1, 37077 Goetingen (Germany); Dirks, A.; Gezzi, R. [Insitute for Theoretical Physics, University of Goettingen, Friedrich-Hund-Platz 1, 37077 Goetingen (Germany)
2009-10-15
We present an extension of the concepts of the functional renormalization group approach to quantum many-body problems in non-equilibrium situations. The approach is completely general and allows calculations for both stationary and time-dependent situations. As a specific example we study the stationary state transport through a quantum dot with local Coulomb correlations. We discuss the influence of finite bias voltage and temperature on the current and conductance.
Phase rule calculations and the thermodynamics of reactive systems under chemical equilibrium
PLATT G. M.; Medeiros,J. L.
1999-01-01
In this paper, we examine the resolution of some phase rule problems within the context of multiple chemical equilibrium reactions, using cubic equations of state and an activity coefficient model. Bubble and dew reactive surfaces, reactive azeotropic loci and reactive critical loci are generated and presented in graphical form. Also isobaric bubble and dew reactive enthalpy loci, which may be useful in the modeling of reactive distillation operations, are depicted. All the formalism here emp...
Turbulent wake vortex system at equilibrium, and its interaction with a ground at ReΓ = 2.0105
Winckelmans, Gregoire; Thiry, Olivier; Duponcheel, Matthieu; Bricteux, Laurent; de Visscher, Ivan
2017-11-01
A turbulent two-vortex system (T-2VS) at statistical equilibrium is first obtained. This is done by putting two vortices with analytical circulation distribution in a weak homogeneous isotropic turbulence field (obtained by LES), and then further running the LES. The system goes unstable and a turbulent equilibrium is obtained after some transient. This is believed to be representative of the state reached by the wake behind a real aircraft, when it is fully rolled up. The T-2VS is also characterized (vortex circulation profile, turbulence, etc.), which provides useful information to support further modeling and theory. Next, that T-2VS wake is put in near ground proximity, and a wall-resolved LES at ReΓ = Γ / ν = 2.0105 is carried out: this is ten times larger than the published works on wake vortices interacting with a ground. As the T-2VS comes down, it goes in ground effects (IGE), and then strongly interacts with the ground and rebounds. The physics of the interaction with the ground are analyzed (also relatively to previous works where the 2VS was made of 2D analytical vortices with white noise added), and diagnostics are obtained: vortex rebound and trajectory, vortex global circulation decay, state of the vortices long after rebound (also an equilibrium).
Purkayastha, Archak; Dhar, Abhishek; Kulkarni, Manas
2016-06-01
We present the Born-Markov approximated Redfield quantum master equation (RQME) description for an open system of noninteracting particles (bosons or fermions) on an arbitrary lattice of N sites in any dimension and weakly connected to multiple reservoirs at different temperatures and chemical potentials. The RQME can be reduced to the Lindblad equation, of various forms, by making further approximations. By studying the N =2 case, we show that RQME gives results which agree with exact analytical results for steady-state properties and with exact numerics for time-dependent properties over a wide range of parameters. In comparison, the Lindblad equations have a limited domain of validity in nonequilibrium. We conclude that it is indeed justified to use microscopically derived full RQME to go beyond the limitations of Lindblad equations in out-of-equilibrium systems. We also derive closed-form analytical results for out-of-equilibrium time dynamics of two-point correlation functions. These results explicitly show the approach to steady state and thermalization. These results are experimentally relevant for cold atoms, cavity QED, and far-from-equilibrium quantum dot experiments.
de Almeida, A. K., Jr.; Prado, A. F. B. A.; Sanchez, D. M.; Yokoyama, T.
2017-10-01
Regarding practical applications of L3 of the Sun-Earth system, there are few studies with the goal of placing a spacecraft at this point, or in orbit around it. One of the main problems in placing a spacecraft near this equilibrium point is the fact that it is located behind the Sun with respect to the Earth. The Sun would be blocking direct communication between the spacecraft and the Earth. The present research gives several options to solve this problem by using a solar sail to place one or two spacecraft above and/or below the Ecliptic plane. This sail could also be used for the mission itself, to collect energy or particles. By using an adequate size, location and attitude of the solar sail, the equilibrium point can be moved from its original location to allow communications between the spacecraft and the Earth. A preliminary study of a solar sail that uses this strategy is shown here.
Odagaki, Takashi
2017-08-01
Extending the concept of the Ginzburg-Landau theory of phase transition to non-equilibrium systems, I present a free energy landscape (FEL) formalism of non-equilibrium statistical mechanics and show that the FEL formalism provides a framework for unified description of thermodynamic and dynamic properties of non-equilibrium systems. I first show that a conditional free energy Φ (T,V,N,{ Ri} ) can be defined as a function of configuration {Ri} of a given average position of atoms so that the probability of finding the configuration {Ri} is in proportion to \\exp [ - Φ (T,V,N,{ Ri} )/kBT]. Thermodynamic quantities in quasi-equilibrium states are given by their average over the configuration, and the temperature dependence of the FEL manifests itself in the temperature derivatives of thermodynamic quantities. As an example, I discuss the entropy and the specific heat, focusing on the contributions due to configuration and the temperature dependence of the FEL, and show that an additional contribution due to the temperature dependence of the FEL exists in the specific heat. I generalize the FEL formalism so that time dependent phenomena can be analyzed in a frame work similar to the time-dependent Ginzburg-Landau theory. I introduce a time-dependent probability function of configuration and describe its time dependence by a Fokker-Planck equation which guarantees that the probability function satisfies the initial condition and the proper long-time limit. The time dependence of a physical quantity is given by its average over the time-dependent distribution function. In order to show the robustness of the FEL formalism in explaining thermodynamic and dynamic effects in a unified frame work, I discuss several phenomena found in super-cooled liquids on the basis of the FEL formalism which includes glass transition singularities, slow relaxations, cooling rate dependence of the specific heat, the ac specific heat, temperature dependence of the crystallization time and
Energy Technology Data Exchange (ETDEWEB)
Smith, C E; Spakovsky, M R von [Center for Energy Systems Research, M.E. Department Virginia Polytechnic Institute and State University, Blacksburg, VA (United States); Sciacovelli, A; Verda, V, E-mail: vonspako@vt.ed [Department of Energy Engineering, Politecnico di Torino, c.so Duca degli Abruzzi 24, 10129 Torino (Italy)
2010-06-01
Quantum thermodynamics (QT) provides a general framework for the description of non-equilibrium phenomena at any level, particularly the atomistic one. This theory and its dynamical postulate are used here to model the storage of hydrogen on and in a carbon nanotube. The tube is placed at the center of a tank with a volume of 250 nm{sup 3}. The thermodynamic system of interest is the hydrogen, which is assumed isolated and having boundaries that coincide with the walls of the tank and the carbon nanotube. The hydrogen is initially prepared in a state far from stable equilibrium (i.e., with the hydrogen molecules probabilistically near one of the outer tank walls) after which the system is allowed to relax (evolve) to a state of stable equilibrium. To predict this evolution in state, the so-called energy eigenvalue problem, which entails a many-body problem that for dilute and moderately dense gases can be modeled using virial expansion theory, is first solved for the geometry involved. The energy eigenvalues and eigenstates of the system found are then used by the nonlinear Beretta equation of motion of QT to determine the evolution of the thermodynamic state of the system as well as the 3D spatial distributions of the hydrogen molecules in time. The simulation results provide a quantification of the entropy generated due to irreversibilities at an atomistic level and show in detail the trajectory of the thermodynamic state of the system as the hydrogen molecules, which are initially arranged to be far from the carbon nanotube, spread out in the system and eventually become probabilistically more concentrated near the carbon atoms, which make up the nanotube.
Heat exchanger optimization for geothermal district heating systems: A fuel saving approach
Energy Technology Data Exchange (ETDEWEB)
Dagdas, Ahmet [Department of Mechanical Engineering, Yildiz Technical University, 34349 Besiktas, Istanbul (Turkey)
2007-05-15
One of the most commonly used heating devices in geothermal systems is the heat exchanger. The output conditions of heat exchangers are based on several parameters. The heat transfer area is one of the most important parameters for heat exchangers in terms of economics. Although there are a lot of methods to optimize heat exchangers, the method described here is a fairly easy approach. In this paper, a counter flow heat exchanger of geothermal district heating system is considered and optimum design values, which provide maximum annual net profit, for the considered heating system are found according to fuel savings. Performance of the heat exchanger is also calculated. In the analysis, since some values are affected by local conditions, Turkey's conditions are considered. (author)
Florentina A. Cziple
2006-01-01
The paper presents a model for establishing the mathematical functions of the liquidus and solidus curves, from the binary diagrams Al-Si, Si-Cu, Cu-Al and their use in the prognosis of the phase equilibrium diagram from the ternary system Al-Cu-Si. We have studied the model of the non-ideal liquid solution of the regular type. The calculus and graphic plotting of the equations for the binary systems has been performed on the computer with the software programmes MathC...
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
Vlad, Marcel O; Popa, Vlad T; Ross, John
2011-02-03
We examine the problem of consistency between the kinetic and thermodynamic descriptions of reaction networks. We focus on reaction networks with linearly dependent (but generally kinetically independent) reactions for which only some of the stoichiometric vectors attached to the different reactions are linearly independent. We show that for elementary reactions without constraints preventing the system from approaching equilibrium there are general scaling relations for nonequilibrium rates, one for each linearly dependent reaction. These scaling relations express the ratios of the forward and backward rates of the linearly dependent reactions in terms of products of the ratios of the forward and backward rates of the linearly independent reactions raised to different scaling powers; the scaling powers are elements of the transformation matrix, which relates the linearly dependent stoichiometric vectors to the linearly independent stoichiometric vectors. These relations are valid for any network of elementary reactions without constraints, linear or nonlinear kinetics, far from equilibrium or close to equilibrium. We show that similar scaling relations for the reaction routes exist for networks of nonelementary reactions described by the Horiuti-Temkin theory of reaction routes where the linear dependence of the mechanistic (elementary) reactions is transferred to the overall (route) reactions. However, in this case, the scaling conditions are valid only at the steady state. General relationships between reaction rates of the two levels of description are presented. These relationships are illustrated for a specific complex reaction: radical chlorination of ethylene.
Directory of Open Access Journals (Sweden)
Hadi Jasim Arkan
2013-01-01
Full Text Available One of the most important design considerations which should not be ignored during the equipment designing for some industrial purpose is vapour-liquid equilibrium (VLE. Thus, in chemical engineering, the first step is the computation of VLE properties of materials by employing Equation of state (EOS. In this study, we have used a thermodynamic model which was established for binary system of carbon dioxide (1-(2 solubility of CO2 in aqueous ethanol and it was employed to estimate the gas-liquid equilibrium at moderate pressures (till 6 bar and varying temperatures (288 K to 323 K. Peng-Robinson EOS was employed to determine the VLE properties. Mixing rules such as vanderWaals and quadratic mixing rules were also used for the determination of ethanol-water mixture critical parameters which entails the pseudo-critical method as one component and results obtained from this study were similar to the ones reported in recent literature for empirical phase equilibrium studies.
40 CFR 63.11499 - What are the standards and compliance requirements for heat exchange systems?
2010-07-01
... requirements for heat exchange systems? 63.11499 Section 63.11499 Protection of Environment ENVIRONMENTAL... and compliance requirements for heat exchange systems? (a) If the cooling water flow rate in your heat... part 211, you may use the physical integrity of the reactor as the surrogate indicator of heat...
Directory of Open Access Journals (Sweden)
E. I. Goncharov
2010-03-01
Full Text Available When personal data exchange between informational systems takes place, one must guarantee the systems are not integrating but just interacting. This task can not be accomplished by using traditional tools such as firewalls, cryptography and so on. To solve the problem we suggest deploying of informational gateway in personal data exchange process.
Performance enhancement study of mobile air conditioning system using microchannel heat exchangers
Energy Technology Data Exchange (ETDEWEB)
Qi, Zhaogang; Zhao, Yu.; Chen, Jiangping [Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, No. 800, Dongchuan Road, Shanghai 200240 (China)
2010-03-15
In the present paper, two retrofitted compact and high efficient microchannel heat exchangers were proposed. The new microchannel heat exchangers have advantages in compactness (17.2% and 15.1% volume reduction for evaporator and condenser, respectively), weight (2.8% and 14.9% lighter for evaporator and condenser, respectively), heat transfer characteristics compared with the currently used heat exchangers in mobile air conditioning (MAC) industry. One enhanced and one baseline R134a MAC systems were established including the new microchannel heat exchangers and the traditional MAC heat exchangers, respectively. The system performances have been experimentally carried out under variable ambient conditions in psychrometric calorimeter test bench. The optimal system refrigerant charge amounts for both systems were tested and the results showed that the enhanced system with more compact heat exchangers could reduce system charge amount and the minimum effective charge amount was less than that of the baseline system. The enhanced system could supply more cooling capacity to car compartment under all test conditions because of higher performance heat exchangers. The coefficient of performance (COP) of the enhanced system was slightly lower than that of the baseline system under idle conditions but higher under all the other test conditions. Cooling capacity and COP of the enhanced system was increased by about 5% and 8% under high vehicle speed condition. (author)
Long-run equilibrium relationships in the international stock market factor systems
Directory of Open Access Journals (Sweden)
Hyung-Suk Choi
2014-06-01
Full Text Available The main objective of this paper is to investigate the international linkages among local, country-specific stock market factors in order to better understand the dependence structure of increasingly integrated world financial markets. The seeming discordance between Fama and French (1998 and Griffin (2002 regarding the multi-factor model in the international stock markets motivates us to study the international relationship among local factors. With the individual stock data from the six major developed countries in the international stock market, we compose daily returns to the Fama-French three factors (i.e. market, size, and value and the momentum factor over the period from January 2000 to June 2010. We investigate the international linkages among local stock market factors, focusing on their equilibrium relationship in the integrated world financial market. The cointegration analysis indicates that local factor indices, constructed from the cumulative factor returns, are cointegrated for each of the four factor classes. Thus, we conclude that local factors are globally bound to each other through a long-run equilibrium relationship and that although stock market factors may be local, rather than global, individual stock returns are driven by common global stochastic trends.
Using a health information exchange system for imaging information: patterns and predictors.
Vest, Joshua R; Grinspan, Zachary M; Kern, Lisa M; Campion, Thomas R; Kaushal, Rainu
2013-01-01
Health information exchange (HIE) systems may address the challenges that prevent easy access to patients' existing radiological information at the point of care. However, little is known about the factors associated with usage of HIE for radiology reports, nor about how reports are shared with an exchange network. We analyzed the system log files from a regional health information organization in upstate New York matched with insurance claims files using network analysis and regression modeling. The exchange network was dominated by a few key information sources. Outpatient users overall accessed 17 times more radiology reports than inpatient and ED users combined. Additionally, as the number of exchange partners increased per organization, the average number of reports exchanged by that organization also increased. Radiology reports were most likely to be accessed by physicians and other clinical users. These findings have implications for those operating and fostering exchange activity.
Effects and Implications for Adoption of Brokerage System in Korea's Foreign Exchange Market
Directory of Open Access Journals (Sweden)
Yunjong Wang
1999-03-01
Full Text Available Since January 1st 1999, the South Korean government has begun to establish the understructure of the foreign exchange market in order to achieve the liberalization of foreign exchange. As one of the plans, the trade of foreign exchange which was under the monopolized mediation of the capital medium of financial settlement center will be in the charge of several commercial brokers. In the developed countries, the foreign exchange & stock system and the liberalization of foreign exchange are both widely used in a flexible way. So it is predicted that the introduction of commercial foreign exchange & stock system will bring positive effect to the enhancement of the market efficiency and the function of price both in South Korean market and overseas market, the foster of competitive power of the domestic broker and the improvement of the understructure of domestic foreign exchange market. But more importantly is that the foreign exchange market must expand the scale of its participator, bring in various relevant foreign exchange products and develop the bond market which has a close relationship with the foreign exchange market for further development.
Model-based analysis of anion-exchanger positioning in direct methanol fuel cell systems
Kraus, Maik; Schröder, Daniel; Krewer, Ulrike
2014-09-01
In this work we present a model based study to investigate the presence of anion exchangers in direct methanol fuel cell (DMFC) systems. It is well known that environmental or fuel impurities lead to accumulation of harmful anions, such as chloride, in the system. However, due to DMFC anodic reaction, a carbonate system is present. These corbanate anions have to be taken into account for the anion exchanger design and placement as well as for the system operation strategy with and without anion exchanger, which is the objective of this study. For this purpose, the expected amount of harmful chloride ions in a DMFC system is estimated, and that of carbonate ions is calculated with a model of the carbonate system in a DMFC system. The predicition of durability and dimensions of an anion exchanger is based on a monovalent anion exchange model. The design of gas liquid separators in the DMFC system has a major influence on the amount of dissolved carbon dioxide, which is crucial for durability and dimension of a system integrated anion exchanger. Finally, feasible positions of anion exchanger in a DMFC system are elaborated to fulfill the needs for long term and stable DMFC operation.
Xia, Longgong; Liu, Zhihong; Taskinen, Pekka
2016-12-01
Phase relationships of the Cu-O-ZnO-CaO system in equilibrium with air ( p tot = 1 atm, p_{{{{O}}2 }} = 0.21 {{atm}} ) have been studied using the equilibration and quenching technique within the temperature range from 1273 K to 1773 K (1000 °C to 1500 °C). The chemical compositions of the molten oxide and solid phases in equilibrium were analyzed by EPMA. The eutectic point in the Cu-O-ZnO-CaO system was found to be 1293 K ± 2 K (1020 °C ± 2 °C) and 0.6785 mole fraction tenorite (`CuO'), 0.1793 mole fraction halite (CaO), and 0.1422 mole fraction wurtzite (ZnO). The results from the present study have been used in constructing the liquidus surface of the Cu-O-ZnO-CaO system. The liquidus surface expands dramatically along with increasing temperature, and it moves simultaneously toward the primary phase fields of wurtzite (ZnO) and halite (CaO). The constructed liquidus surfaces have been compared with the isothermal sections (`Cu2O'-ZnO-CaO) calculated by MTDATA 5.10 software and its Mtox 8.1 database. Deviations between the thermodynamically assessed diagrams and the experimental results are significant. Thus, the system requires a reassessment.
Energy Technology Data Exchange (ETDEWEB)
Zhang, Delu, E-mail: deluzh@163.com [Department of Lifescience and Biotechnology, College of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070 (China); Liu, Siyi [Department of Lifescience and Biotechnology, College of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070 (China); Zhang, Jing [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Zhang, Jian Kong [Department of Lifescience and Biotechnology, College of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070 (China); Hu, Chunxiang, E-mail: deluzh@ihb.ac.cn [Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan 430072 (China); Liu, Yongding [Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan 430072 (China)
2016-08-15
Highlights: • Aphantoxins induce respiratory dysfunction in zebrafish gills. • Changes in LDH and cellular ultrastructure indicate gill damage. • Decreased NKA and CA reflect abnormal ion transport and gas exchange. • Increased ROS and decreased T-AOC suggest oxidative stress in the gills. - Abstract: Aphantoxins, neurotoxins or paralytic shellfish poisons (PSPs) generated by Aphanizomenon flos-aquae, are a threat to environmental safety and human health in eutrophic waters worldwide. The molecular mechanisms of neurotoxin function have been studied; however, the effects of these neurotoxins on oxidative stress, ion transport, gas exchange, and branchial ultrastructure in fish gills are not fully understood. Aphantoxins extracted from A. flos-aquae DC-1 were detected by high-performance liquid chromatography. The major ingredients were gonyautoxins 1 and 5 and neosaxitoxin, which comprised 34.04%, 21.28%, and 12.77% of the total, respectively. Zebrafish (Danio rerio) were administered A. flos-aquae DC-1 aphantoxins at 5.3 or 7.61 μg saxitoxin equivalents (eq)/kg (low and high doses, respectively) by intraperitoneal injection. The activities of Na{sup +}-K{sup +}-ATPase (NKA), carbonic anhydrase (CA), and lactate dehydrogenase (LDH), ultrastructural alterations in chloride and epithelial cells, and reactive oxygen species (ROS) and total antioxidative capacity (T-AOC) were investigated in the gills during the first 24 h after exposure. Aphantoxins significantly increased the level of ROS and decreased the T-AOC in zebrafish gills from 3 to 12 h post-exposure, suggesting an induction of oxidative stress and inhibition of antioxidant capacity. Reduced activities of NKA and CA demonstrated abnormal ion transport and gas exchange in the gills of aphantoxin-treated fish. Toxin administration also resulted in increased LDH activity and ultrastructural alterations in chloride and epithelial cells, suggesting a disruption of function and structure in zebrafish
Khadra, Ibrahim; Zhou, Zhou; Dunn, Claire; Wilson, Clive G; Halbert, Gavin
2015-01-25
A drug's solubility and dissolution behaviour within the gastrointestinal tract is a key property for successful administration by the oral route and one of the key factors in the biopharmaceutics classification system. This property can be determined by investigating drug solubility in human intestinal fluid (HIF) but this is difficult to obtain and highly variable, which has led to the development of multiple simulated intestinal fluid (SIF) recipes. Using a statistical design of experiment (DoE) technique this paper has investigated the effects and interactions on equilibrium drug solubility of seven typical SIF components (sodium taurocholate, lecithin, sodium phosphate, sodium chloride, pH, pancreatin and sodium oleate) within concentration ranges relevant to human intestinal fluid values. A range of poorly soluble drugs with acidic (naproxen, indomethacin, phenytoin, and piroxicam), basic (aprepitant, carvedilol, zafirlukast, tadalafil) or neutral (fenofibrate, griseofulvin, felodipine and probucol) properties have been investigated. The equilibrium solubility results determined are comparable with literature studies of the drugs in either HIF or SIF indicating that the DoE is operating in the correct space. With the exception of pancreatin, all of the factors individually had a statistically significant influence on equilibrium solubility with variations in magnitude of effect between the acidic and basic or neutral compounds and drug specific interactions were evident. Interestingly for the neutral compounds pH was the factor with the second largest solubility effect. Around one third of all the possible factor combinations showed a significant influence on equilibrium solubility with variations in interaction significance and magnitude of effect between the acidic and basic or neutral compounds. The least number of significant media component interactions were noted for the acidic compounds with three and the greatest for the neutral compounds at seven
Nagarajan, Ramanathan
2015-07-01
Micelles generated in water from most amphiphilic block copolymers are widely recognized to be non-equilibrium structures. Typically, the micelles are prepared by a kinetic process, first allowing molecular scale dissolution of the block copolymer in a common solvent that likes both the blocks and then gradually replacing the common solvent by water to promote the hydrophobic blocks to aggregate and create the micelles. The non-equilibrium nature of the micelle originates from the fact that dynamic exchange between the block copolymer molecules in the micelle and the singly dispersed block copolymer molecules in water is suppressed, because of the glassy nature of the core forming polymer block and/or its very large hydrophobicity. Although most amphiphilic block copolymers generate such non-equilibrium micelles, no theoretical approach to a priori predict the micelle characteristics currently exists. In this work, we propose a predictive approach for non-equilibrium micelles with glassy cores by applying the equilibrium theory of micelles in two steps. In the first, we calculate the properties of micelles formed in the mixed solvent while true equilibrium prevails, until the micelle core becomes glassy. In the second step, we freeze the micelle aggregation number at this glassy state and calculate the corona dimension from the equilibrium theory of micelles. The condition when the micelle core becomes glassy is independently determined from a statistical thermodynamic treatment of diluent effect on polymer glass transition temperature. The predictions based on this "non-equilibrium" model compare reasonably well with experimental data for polystyrene-polyethylene oxide diblock copolymer, which is the most extensively studied system in the literature. In contrast, the application of the equilibrium model to describe such a system significantly overpredicts the micelle core and corona dimensions and the aggregation number. The non-equilibrium model suggests ways to
Zhang, Yin; Wei, Zhiyuan; Zhang, Yinping; Wang, Xin
2017-12-01
Urban heating in northern China accounts for 40% of total building energy usage. In central heating systems, heat is often transferred from heat source to users by the heat network where several heat exchangers are installed at heat source, substations and terminals respectively. For given overall heating capacity and heat source temperature, increasing the terminal fluid temperature is an effective way to improve the thermal performance of such cascade heat exchange network for energy saving. In this paper, the mathematical optimization model of the cascade heat exchange network with three-stage heat exchangers in series is established. Aim at maximizing the cold fluid temperature for given hot fluid temperature and overall heating capacity, the optimal heat exchange area distribution and the medium fluids' flow rates are determined through inverse problem and variation method. The preliminary results show that the heat exchange areas should be distributed equally for each heat exchanger. It also indicates that in order to improve the thermal performance of the whole system, more heat exchange areas should be allocated to the heat exchanger where flow rate difference between two fluids is relatively small. This work is important for guiding the optimization design of practical cascade heating systems.
Directory of Open Access Journals (Sweden)
R.A.G. Sé
2002-04-01
Full Text Available The NRTL (nonrandom, two-liquid model, expressed in mass fraction instead of mole fraction, was used to correlate liquid-liquid equilibria for aqueous two-phase polymer-salt solutions. New interaction energy parameters for this model were determined using reported data on the water + poly(ethylene glycol + salt systems, with different molecular masses for PEG and the salts potassium phosphate, sodium sulfate, sodium carbonate and magnesium sulfate. The correlation of liquid-liquid equilibrium is quite satisfactory.
Directory of Open Access Journals (Sweden)
Kuznetsov Vladimir V.
2017-01-01
Full Text Available Multiscale processes of self-organization of the flow and non-equilibrium heat and mass transfer during the separation of a binary mixture in a multiphase system formed by a structural packing and a counter-flow vapor-liquid flow are considered. The conditions for the appearance of large-scale convective flow during separation of the binary mixture of refrigerants R21-R114 in a distillation column with Koch 1Y structure packing are obtained. The physical properties of this mixture are similar to the properties of air component at cryogenic temperatures.
Rezvani, Mohammad Hossein; Analoui, Morteza
2010-11-01
We have designed a competitive economical mechanism for application level multicast in which a number of independent services are provided to the end-users by a number of origin servers. Each offered service can be thought of as a commodity and the origin servers and the users who relay the service to their downstream nodes can thus be thought of as producers of the economy. Also, the end-users can be viewed as consumers of the economy. The proposed mechanism regulates the price of each service in such a way that general equilibrium holds. So, all allocations will be Pareto optimal in the sense that the social welfare of the users is maximized.
Entropy Production and Equilibrium Conditions of General-Covariant Spin Systems
Directory of Open Access Journals (Sweden)
Wolfgang Muschik
2015-12-01
Full Text Available In generalizing the special-relativistic one-component version of Eckart’s continuum thermodynamics to general-relativistic space-times with Riemannian or post-Riemannian geometry as presented by Schouten (Schouten, J.A. Ricci-Calculus, 1954 and Blagojevic (Blagojevic, M. Gauge Theories of Gravitation, 2013 we consider the entropy production and other thermodynamical quantities, such as the entropy flux and the Gibbs fundamental equation. We discuss equilibrium conditions in gravitational theories, which are based on such geometries. In particular, thermodynamic implications of the non-symmetry of the energy-momentum tensor and the related spin balance equations are investigated, also for the special case of general relativity.
Viguera, Ana-Rosa; Serrano, Luis
2003-01-01
Amide hydrogen/deuterium exchange rates have been determined for two mutants of α-spectrin Src homology 3 domain (WT), containing an elongated stable (SHH) and unstable (SHA) distal loop. SHA, similarly to WT, follows a two-state transition, whereas SHH apparently folds via a three-state mechanism. Native-state amide hydrogen exchange is effective in ascribing energetic readjustments observed in kinetic experiments to species stabilized within the denatured base and distinguishing those from high-energy barrier crossings. Comparison of ΔGex and mex parameters for amide protons of these mutants demonstrates the existence of an intermediate and allows the identification of protons protected in this state. The consolidation of a form containing a prefolded long β-hairpin induces the switch to a three-state mechanism in an otherwise two-state folder. It can be inferred that the unbalanced high stability of individual elements of secondary structure in a polypeptide could ultimately complicate its folding mechanism. PMID:12719536
Energy Technology Data Exchange (ETDEWEB)
Chen, Xin, E-mail: xin.chen.nj@gmail.com [Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
2014-04-21
Understanding the roles of the temporary and spatial structures of quantum functional noise in open multilevel quantum molecular systems attracts a lot of theoretical interests. I want to establish a rigorous and general framework for functional quantum noises from the constructive and computational perspectives, i.e., how to generate the random trajectories to reproduce the kernel and path ordering of the influence functional with effective Monte Carlo methods for arbitrary spectral densities. This construction approach aims to unify the existing stochastic models to rigorously describe the temporary and spatial structure of Gaussian quantum noises. In this paper, I review the Euclidean imaginary time influence functional and propose the stochastic matrix multiplication scheme to calculate reduced equilibrium density matrices (REDM). In addition, I review and discuss the Feynman-Vernon influence functional according to the Gaussian quadratic integral, particularly its imaginary part which is critical to the rigorous description of the quantum detailed balance. As a result, I establish the conditions under which the influence functional can be interpreted as the average of exponential functional operator over real-valued Gaussian processes for open multilevel quantum systems. I also show the difference between the local and nonlocal phonons within this framework. With the stochastic matrix multiplication scheme, I compare the normalized REDM with the Boltzmann equilibrium distribution for open multilevel quantum systems.
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.
Fabrication of Flat Plate Solar Geyser with Flat Grooved Heat Exchanger Having Special Exit System
Muhammad Suleman Malik; Muhammad Arsalan Malik; Haseeb Ali Shah; Adnan Anwar khan afridi; Muhammad Asif
2017-01-01
The main objective of this paper is to introduce the concept of novel flat plate solar geyser with integrated heat exchanger and open loop passive system.The heat exchanger acts both as collector for solar radiations and as a heat exchanger its self for cold water beneath it. Contrary to the conventional flat plate solar collectors, water is in direct contact with the collector or flat grooved heat exchanger. A safety control box is installed to minimize hydraulic pressure of cold water rese...
Fundamentals for magnetic patterning by ion bombardment of exchange bias layer systems
Energy Technology Data Exchange (ETDEWEB)
Ehresmann, A.; Engel, D.; Weis, T. [Institute of Physics and Centre for Interdisciplinary Nanostructure Science and Technology (CINSaT), Kassel University, Heinrich-Plett-Str. 40, 34132 Kassel (Germany); Schindler, A. [Institut fuer Festkoerperforschung, Forschungszentrum Juelich GmbH, 52425 Juelich (Germany); Junk, D. [Technische Physik, Universitaet des Saarlandes, P.O. Box 151150, 66041 Saarbruecken (Germany); Schmalhorst, J.; Hoeink, V.; Sacher, M.D.; Reiss, G. [Faculty of Physics, Bielefeld University, P.O. Box 100131, 33501 Bielefeld (Germany)
2006-01-01
In the present paper we investigate whether the ion bombardment induced magnetic modifications in exchange biased bilayers are stable in time, whether the direction of the exchange bias can be set to any arbitrary (in-plane) direction by the ion bombardment and whether the exchange bias field can be changed in successive bombardment steps. These three fundamental characteristics are prerequisites for ion bombardment used for an efficient, practical, and stable magnetic patterning of exchange biased layer systems. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
Stary, J
1979-01-01
Critical Evaluation of Equilibrium Constants Involving 8-Hydroxyquinoline and Its Metal Chelates presents and evaluates the published data on the solubility, dissociation, and liquid-liquid distribution of oxine and its metal chelates to recommend the most reliable numerical data. This book explores the dissociation constants of oxine in aqueous solutions.Organized into four chapters, this book begins with an overview of the characteristics of 8-hydroxyquinoline (oxine). This text then examines the total solubility of oxine in aqueous solution at different pH values. Other chapters consider th
Development of a Malian food exchange system based on local ...
African Journals Online (AJOL)
Energy and macronutrient intakes obtained by a software-based nutritional analysis of the dietary recalls were compared with the average energy and nutrient values calculated with the exchange lists. Setting: Centre National de Lutte contre le Diabète. Subjects: Seventeen male and 40 female adults with type 2 diabetes.
Directory of Open Access Journals (Sweden)
Florentina A. Cziple
2006-10-01
Full Text Available The paper presents a model for establishing the mathematical functions of the liquidus and solidus curves, from the binary diagrams Al-Si, Si-Cu, Cu-Al and their use in the prognosis of the phase equilibrium diagram from the ternary system Al-Cu-Si. We have studied the model of the non-ideal liquid solution of the regular type. The calculus and graphic plotting of the equations for the binary systems has been performed on the computer with the software programmes MathCad 2000 Professional, Statistica 5, Curve Expert, and for the ternary system Al-Cu-Si, with the 3D StudioMax software
Directory of Open Access Journals (Sweden)
Yumei Li
2014-09-01
Full Text Available Isobaric vapor-liquid equilibrium (VLE data for the cyclopentane and tetrahydrofuran (THF system were measured at 101.3 kPa by using an equilibrium still. Thermodynamic consistency of the experimental data was confirmed by means of the Herington method. The experimental data were correlated and calculated by the Margules, Van Laar and Wilson activity-coefficient models, respectively. The Wilson and Van Laar activity-coefficient models are better than the Margules activity-coefficient model based on the average absolute deviations of temperature and the vapor-phase composition. For the Wilson and Van Laar activity-coefficient models the average absolute deviations between the experimental and the calculated values were 0.24 K and 0.23 K for the boiling point, and 0.0040 for vapor-phase composition, respectively. These agree well with the experimental data. Therefore, it was shown that the Wilson and Van Laar activity-coefficient models satisfactorily correlate the experimental results of the cyclopentane and tetrahydrofuran system.
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.
Design and study of the mask exchange system based on Delta parallel mechanism
Zhang, Feifan; Wang, Jianping; Zhou, Hongfei; Zhou, Zengxiang; Chu, Jiaru
2016-07-01
Mask exchange system is the main part of Multi-Object Broadband Imaging Echellette (MOBIE) on the Thirty Meter Telescope (TMT). The robot is one of the key parts in the mask exchange process. In view of the facts that the scheme the on-board robot is hard to meet the requirements of TMT and the traditional industrial robot is difficult to use in the Mask Exchange System (MEX). The delta parallel mechanism has much advantages such as good dynamic performance, high speed and could integrate a vision recognition system to identify the masks. The design for MEX based on off-board Delta parallel mechanism was proposed in the paper.
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
Nunes, Diego L; Oliveira, Leandro S; Franca, Adriana S
2015-01-01
Melanoidins are colored products that can be found in food and drinks, formed by Maillard reactions. Sometimes these compounds are considered undesirable in certain food products, because they impart a brownish color and must be removed. An overview of recent patents related to melanoidin removal indicates that it can be performed by chemical/biological degradation or by adsorption processes. Therefore, in the present study, the adsorption mechanism for synthetic melanoidin removal from aqueous solutions was studied using different Raphanus sativus press-cake sorbents, with the precursor material being carbonized in a microwave oven, either with direct heating or after a chemical activation process with phosphoric acid, nitric acid or potassium hydroxide. Physical and chemical modifications were evaluated by FTIR, pHPZC, thermogravimetry and BET. The adsorption kinetics was better described by a pseudo-second order model for all activated carbons (ACs). Evaluation of the diffusion process showed dependence on the initial melanoidin concentration due to the wide range of sizes of the adsorbed molecules. The equilibrium data were best fitted by the Langmuir model for the acid-treated AC and by the Freundlich model for the base-treated and non-chemically treated ACs. Melanoidin adsorption was characterized as a spontaneous, favorable and endothermic process involving hydrogen bonds and π-π interactions between the adsorbents surfaces and the adsorbed molecules.
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…
Measuring and Modeling Component and Whole-System Carbon Exchange
Energy Technology Data Exchange (ETDEWEB)
Paul Bolstad
2006-11-01
We measured ecosystem/atmospheric carbon exchange through a range of methods covering a range of scales. We measured carbon (C) pool and flux for a number of previously poorly quantified ecosystems, developed measurement and modeling methods, and applied these to substantially increase the accuracy and reduce uncertainty in ecosystem/atmospheric C exchange at a range of scales. It appears most upland forests are weak to strong carbon sinks, and status depends largely on disturbance history and age. Net flux from wetland ecosystems appears to be from weak sinks to moderate sources of C to the atmosphere. We found limited evidence for a positive feedback of warming/drying to increased ecosystem C emissions. We further developed multi-source integration and modeling methods, including multiple towers, to scale estimates to landscapes and larger regions.
Exchange rate system and policy in the present world
Directory of Open Access Journals (Sweden)
Grubišić Zoran
2005-01-01
Full Text Available The choice of exchange rate regime is important, not only in terms of its effect on trade flows, but also with respect to inflation expectations. Countries facing disinflation may find that pegs regimes are more appropriate solution. But where the trade balance account is significantly deteriorated and growth has been sluggish, a more flexible regime might be called for. The natural classification in eighties and early nineties suggests that intermediate regimes may provide important advantages – to capture some of the benefits of both extremes while avoiding many of the costs. However today many experts predicted that exchange rate regimes would move in a "bipolar" manner to the extremes of "hard" pegs or free floats. An increasing number of countries did announce their intent to allow greater exchange rate flexibility. But, in practice, countries had a "fear of floating ". Distinction is made among advanced, emerging and other developing countries. Emerging markets have stronger links to international capital markets than do other developing economies. Thus, while non-emerging market developing economies may gain credibility through pegging their exchange rates, emerging markets find it harder to do so and could benefit from investing in "learning to float". More advanced economies with their access to international capital market are best positioned to enjoy the benefits of flexibility. It is found that the proportion of countries adopting intermediate regimes has indeed been shrinking in favor of greater flexibility or greater fixity, especially for countries more integrated with international markets. But, there is no final conclusion on the idea that intermediate regimes will dissapear.
Lísal, Martin; Brennan, John K; Smith, William R
2006-10-28
We present a mesoscale simulation technique, called the reaction ensemble dissipative particle dynamics (RxDPD) method, for studying reaction equilibrium of polymer systems. The RxDPD method combines elements of dissipative particle dynamics (DPD) and reaction ensemble Monte Carlo (RxMC), allowing for the determination of both static and dynamical properties of a polymer system. The RxDPD method is demonstrated by considering several simple polydispersed homopolymer systems. RxDPD can be used to predict the polydispersity due to various effects, including solvents, additives, temperature, pressure, shear, and confinement. Extensions of the method to other polymer systems are straightforward, including grafted, cross-linked polymers, and block copolymers. To simulate polydispersity, the system contains full polymer chains and a single fractional polymer chain, i.e., a polymer chain with a single fractional DPD particle. The fractional particle is coupled to the system via a coupling parameter that varies between zero (no interaction between the fractional particle and the other particles in the system) and one (full interaction between the fractional particle and the other particles in the system). The time evolution of the system is governed by the DPD equations of motion, accompanied by changes in the coupling parameter. The coupling-parameter changes are either accepted with a probability derived from the grand canonical partition function or governed by an equation of motion derived from the extended Lagrangian. The coupling-parameter changes mimic forward and reverse reaction steps, as in RxMC simulations.
Yoder, Paul J.; Lieberman, Rebecca G.
2010-01-01
A randomized control trial comparing two social-communication interventions in young children with autism examined far-transfer of the use of picture exchange to communicate. Thirty-six children were randomly assigned to one of two treatment conditions, one of which was the Picture Exchange Communication System (PECS). All children had access to picture symbols during assessments. Post-treatment measurement of the number of picture exchanges in a far-transfer, assessment context favored the P...
Si, Wen; Si, Jianguo
2017-05-01
By developing two KAM theorems, in this paper, we show that two classes of quasi-periodically forced four-dimensional nonlinear systems with degenerate equilibrium point, a reversible system and a non-conservative system, admit a response solution under small perturbations. For the degenerate reversible system, applying special structure of unperturbed nonlinear term and Herman method, we successfully control the shift of equilibrium point, which is difficult in view of the degenerate linear term. For the degenerate non-conservative system, KAM method is brought into force even in completely degenerate case because of the restrictions on the smallness and average of perturbation. Moreover, arithmetic condition on the frequency is assumed to satisfy the Brjuno-Rüssmann's non-resonant condition. By the Pöschel-Rüssmann KAM method, we prove that these two kinds of perturbed systems can be reduced to a suitable normal form with zero as equilibrium point by a quasi-periodic transformation.
2010-01-01
... Student and Exchange Visitor Information System (SEVIS). 214.12 Section 214.12 Aliens and Nationality... of schools in the Student and Exchange Visitor Information System (SEVIS). (a) Private elementary and... schools are eligible for preliminary enrollment in Student and Exchange Visitor Information System (SEVIS...
Shpielberg, O; Akkermans, E
2016-06-17
A stability analysis is presented for boundary-driven and out-of-equilibrium systems in the framework of the hydrodynamic macroscopic fluctuation theory. A Hamiltonian description is proposed which allows us to thermodynamically interpret the additivity principle. A necessary and sufficient condition for the validity of the additivity principle is obtained as an extension of the Le Chatelier principle. These stability conditions result from a diagonal quadratic form obtained using the cumulant generating function. This approach allows us to provide a proof for the stability of the weakly asymmetric exclusion process and to reduce the search for stability to the solution of two coupled linear ordinary differential equations instead of nonlinear partial differential equations. Additional potential applications of these results are discussed in the realm of classical and quantum systems.
A novel four-wing non-equilibrium chaotic system and its circuit ...
Indian Academy of Sciences (India)
In this paper, we construct a novel, 4D smooth autonomous system. Compared to the existing chaotic systems, the most attractive point is that this system does not display any equilibria, but can still exhibit four-wing chaotic attractors. The proposed system is investigated through numerical simulations and analyses including ...
Equilibrium phases in the multiferroic BiFeO3-PbTiO3 system – a revisit
Directory of Open Access Journals (Sweden)
Kothai V.
2014-07-01
Full Text Available The(1-x BiFeO3-(x PbTiO3 solid solution exhibiting a Morphotropic Phase Boundary (MPB has attracted considerable attention recently because of its unique features such as multiferroic, high Curie point (TC ~ 700°C and giant tetragonality (c/a -1 ~ 0.19. Different research groups have reported different composition range of MPB for this system. In this work we have conclusively proved that the wide composition range of MPB reported in the literature is due to kinetic arrest of the metastable rhombohedral phase and that if sufficient temperature and time is allowed the metastable phase disappears. The genuine MPB was found to be x=0.27 for which the tetragonal and the rhombohedral phases are in thermodynamic equilibrium. In-situ high temperature structural study of x=0.27 revealed the sluggish kinetics associated with the temperature induced structural transformation. Neutron powder diffraction study revealed that themagnetic ordering at room temperature occurs in the rhombohedral phase. The magnetic structure was found to be commensurate G-type antiferromagnetic with magnetic moments parallel to the c-direction (of the hexagonal cell. The present study suggests that the equilibrium properties in this solid solution series should be sought for x=0.27.
Directory of Open Access Journals (Sweden)
O A Habeeb
2017-05-01
Full Text Available The studies of adsorption equilibrium isotherm and kinetics of hydrogen sulfide-water systems on calcite-based adsorbents prepared from eggshell are undertaken. The effects of operating variables such as contact time and initial concentration on the adsorption capacity of hydrogen sulfide are investigated. The modified eggshells are characterized by using different analytical approaches such as Scanning Electron Microscopy (SEM and Fourier Transform Infrared (FTIR. The batch mode adsorption process is performed at optimum removal conditions: dosage of 1 g/L, pH level of pH 6, agitation speed of 150 rpm and contact time of 14h for adsorbing hydrogen sulfide with an initial concentration of 100-500 mg/L. In the current study, the Langmuir, Freundlich, Temkin, and Dubinin models are used to predict the adsorption isotherms. Our equilibrium data for hydrogen sulfide adsorption agrees well with those of the Langmuir equation. The maximum monolayer adsorption capacity is 150.07 mg/g. Moreover, the kinetics of H2S adsorption by using the modified calcite of eggshell follows a pseudo-second-order model. From the current work, we have found that the calcite eggshell is a suitable adsorbent for H2S embeded inside the waste water. Most importantly, chicken eggshell is a waste and vastly available; hence, it could serve as a practical mean for H2S adsorption.
Lucato, Jeanette Janaina Jaber; Adams, Alexander Bernard; Souza, Rogério; Torquato, Jamili Anbar; Carvalho, Carlos Roberto Ribeiro; Marini, John J
2009-01-01
To evaluate and compare the efficiency of humidification in available heat and moisture exchanger models under conditions of varying tidal volume, respiratory rate, and flow rate. Inspired gases are routinely preconditioned by heat and moisture exchangers to provide a heat and water content similar to that provided normally by the nose and upper airways. The absolute humidity of air retrieved from and returned to the ventilated patient is an important measurable outcome of the heat and moisture exchangers' humidifying performance. Eight different heat and moisture exchangers were studied using a respiratory system analog. The system included a heated chamber (acrylic glass, maintained at 37 degrees C), a preserved swine lung, a hygrometer, circuitry and a ventilator. Humidity and temperature levels were measured using eight distinct interposed heat and moisture exchangers given different tidal volumes, respiratory frequencies and flow-rate conditions. Recovery of absolute humidity (%RAH) was calculated for each setting. Increasing tidal volumes led to a reduction in %RAH for all heat and moisture exchangers while no significant effect was demonstrated in the context of varying respiratory rate or inspiratory flow. Our data indicate that heat and moisture exchangers are more efficient when used with low tidal volume ventilation. The roles of flow and respiratory rate were of lesser importance, suggesting that their adjustment has a less significant effect on the performance of heat and moisture exchangers.
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)
Equilibrium isotope effects on noncovalent interactions in a supramolecular host-guest system.
Mugridge, Jeffrey S; Bergman, Robert G; Raymond, Kenneth N
2012-02-01
The self-assembled supramolecular complex [Ga(4)L(6)](12-) (1; L = 1,5-bis[2,3-dihydroxybenzamido]naphthalene) can act as a molecular host in aqueous solution and bind cationic guest molecules to its highly charged exterior surface or within its hydrophobic interior cavity. The distinct internal cavity of host 1 modifies the physical properties and reactivity of bound guest molecules and can be used to catalyze a variety of chemical transformations. Noncovalent host-guest interactions in large part control guest binding, molecular recognition and the chemical reactivity of bound guests. Herein we examine equilibrium isotope effects (EIEs) on both exterior and interior guest binding to host 1 and use these effects to probe the details of noncovalent host-guest interactions. For both interior and exterior binding of a benzylphosphonium guest in aqueous solution, protiated guests are found to bind more strongly to host 1 (K(H)/K(D) > 1) and the preferred association of protiated guests is driven by enthalpy and opposed by entropy. Deuteration of guest methyl and benzyl C-H bonds results in a larger EIE than deuteration of guest aromatic C-H bonds. The observed EIEs can be well explained by considering changes in guest vibrational force constants and zero-point energies. DFT calculations further confirm the origins of these EIEs and suggest that changes in low-frequency guest C-H/D vibrational motions (bends, wags, etc.) are primarily responsible for the observed EIEs. © 2011 American Chemical Society
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...
National Aeronautics and Space Administration — CCT proposes an advanced data description exchange approach for space/spaceport systems that will provide a generic platform independent software capability for...
RRB's SVES Input File - Post Entitlement State Verification and Exchange System (PSSVES)
Social Security Administration — Several PSSVES request files are transmitted to SSA each year for processing in the State Verification and Exchange System (SVES). This is a first step in obtaining...
Gain measurements of the Ca-Xe charge exchange system. [for UV lasers
Michels, C. J.; Chubb, D. L.
1978-01-01
Charge-exchange-pumped Ca(+) was studied for possible positive laser gain at 370.6 and 315.9 nm using an Xe MPD arc as the Xe(+) source. The present paper describes the MPD arc, the calcium injection system, the diagnostics for gain, and spontaneous emission measurements and results. No positive gain measurements were observed. A small Xe-Ca charge exchange cross section compared to He-metal laser systems charge exchange cross sections is the most probable reason why the result was negative.
Directory of Open Access Journals (Sweden)
B. D. Castro
2005-09-01
Full Text Available Liquid-liquid extraction using aqueous two-phase systems is a highly efficient technique for separation and purification of biomolecules due to the mild properties of both liquid phases. Reliable data on the phase behavior of these systems are essential for the design and operation of new separation processes; several authors reported phase diagrams for polymer-polymer systems, but data on polymer-salt systems are still relatively scarce. In this work, experimental liquid-liquid equilibrium data on water + polyethylene glycol 8000 + magnesium sulfate and water + polyethylene glycol 8000 + sodium sulfate aqueous two-phase systems were obtained at 35°C. Both equilibrium phases were analyzed by lyophilization and ashing. Experimental results were correlated with a mass-fraction-based NRTL activity coefficient model. New interaction parameters were estimated with the Simplex method. The mean deviations between the experimental and calculated compositions in both equilibrium phases is about 2%.
Vorberger, J
2016-01-01
We present a quantum theory for the dynamic structure factors in non-equilibrium, correlated, two-component systems such as plasmas or warm dense matter. Using this general framework, we derive expressions for effective local field corrections to the random phase approximation. The polarization function, which is needed as the input for the calculation of the structure factors, is calculated in non-equilibrium based on a perturbation expansion in the interaction strength. To make our theory applicable for x-ray scattering, a generalized Chihara decomposition for the total electron structure factor in non-equilibrium is derived. Examples are given for the special case of equilibrium and for a model bump-on-hot-tail distribution, as often encountered during laser heating of materials.
Yoshikawa, Masahiro; Koga, Nobuyoshi
2016-01-01
This study focuses on students' understandings of a liquid-gas system with liquid-vapor equilibrium in a closed system using a pressure-temperature ("P-T") diagram. By administrating three assessment questions concerning the "P-T" diagrams of liquid-gas systems to students at the beginning of undergraduate general chemistry…
Control and prevention of ice formation and accretion on heat exchangers for ventilation systems
DEFF Research Database (Denmark)
Rahimi, Maral; Afshari, Alireza
2015-01-01
In cold climates, the application of mechanical ventilation systems with heat recovery like are airto-air exchangers is used for reducing energy consumption for heating buildings by transferring heat exhausted air to supply air. However, increase efficiency of heat exchanger results in lower...... exhaust air temperatures and Ice formation on heat exchanger fins, which can cause problem and is not favourable. Therefore, prevention and control of ice formation on heat exchangers is necessary. The existing methods are divided into two different methods: active and passive ice control methods....... The active methods are e.g. bypass, recirculation, preheating. The passive methods relate to the surface characteristics of the heat exchanger fins as they have effect on ice formation in initial phase. All these methods have varying levels of success, cost, and effectiveness, which are depending on the heat...
Parmar, Vandana
2008-08-01
Adequate humidification is vital to maintain homeostasis of the airway. Heat and moisture exchangers conserve some of the exhaled water, heat and return them to inspired gases. Many heat and moisture exchangers also perfom bacterial/viral filtration and prevent inhalation of small particles. Heat and moisture exchangers are also called condenser humidifier, artificial nose, etc. Most of them are disposable devices with exchanging medium enclosed in a plastic housing. For adult and paediatric age group different dead space types are available. Heat and moisture exchangers are helpful during anaesthesia and ventilatory breathing system. To reduce the damage of the upper respiratory tract through cooling and dehydration inspiratory air can be heated and humidified, thus preventing the serious complications.
Yoder, Paul J.; Lieberman, Rebecca G.
2010-01-01
A randomized control trial comparing two social-communication interventions in young children with autism examined far-transfer of the use of picture exchange to communicate. Thirty-six children were randomly assigned to one of two treatment conditions, one of which was the Picture Exchange Communication System (PECS). All children had access to…
Directory of Open Access Journals (Sweden)
S. Vaidyanathan
2014-11-01
Full Text Available Chaos theory has wide applications and its importance can be seen by the voluminous publications on various applications in several branches of science, commerce and engineering. Control, tracking or regulation and synchronization of different types of chaotic systems are importance areas of research in the control literature and various methods have been adopted over the past few decades for tackling these research problems. Also, the discovery of novel chaotic and hyperchaotic systems in various applications, their qualitative properties and the control of such systems are also important research areas in chaos theory. This paper announces a novel 4-D hyperchaotic Rikitake dynamo system, which is derived by adding a state feedback control to the famous 3-D Rikitake two-disk dynamo system (1958. The frequent and irregular reversals of the Earth’s magnetic field inspired a number of early studies involving electrical currents within the Earth’s molten core. One of the first such models to exhibit reversals was Rikitake’s two-disk dynamo system (Rikitake, 1958. This paper discusses the qualitative properties of the novel hyperchaotic Rikitake dynamo system. We note that the novel hyperchaotic Rikitake dynamo system has no equilibrium points. The Lyapunov exponents of the hyperchaotic Rikitake dynamo system are found as �! = 0.09136, �! = 0.02198, �! = 0 and �! = −2.11190. The Kaplan-Yorke fractional dimension of the novel hyperchaotic Rikitake dynamo system is found as �!" = 3.05367. Next, this paper discusses control and synchronization of the novel hyperchaotic Rikitake dynamo system with unknown parameters using adaptive control method. The main results are established using Lyapunov stability theory and numerically illustrated using MATLAB. Finally, for the 4-D novel hyperchaotic system, an electronic circuit realization in SPICE has been described to confirm the feasibility of the theoretical hyperchaotic Rikitake dynamo
Ion-exchange chromatography separation applied to mineral recycle in closed systems
Ballou, E.; Spitze, L. A.; Wong, F. W.; Wydeven, T.; Johnson, C. C.
1981-01-01
As part of the controlled ecological life support system (CELSS) program, a study is being made of mineral separation on ion-exchange columns. The purpose of the mineral separation step is to allow minerals to be recycled from the oxidized waste products of plants, man, and animals for hydroponic food production. In the CELSS application, relatively large quantities of minerals in a broad concentration range must be recovered by the desired system, rather than the trace quantities and very low concentrations treated in analytical applications of ion-exchange chromatography. Experiments have been carried out to assess the parameters pertinent to the scale-up of ion-exchange chromatography and to determine feasibility. Preliminary conclusions are that the column scale-up is in a reasonable size range for the CELSS application. The recycling of a suitable eluent, however, remains a major challenge to the suitability of using ion exchange chromatography in closed systems.
Directory of Open Access Journals (Sweden)
Lu-Chuan Ceng
2014-01-01
Full Text Available We introduce and analyze one iterative algorithm by hybrid shrinking projection method for finding a solution of the minimization problem for a convex and continuously Fréchet differentiable functional, with constraints of several problems: finitely many generalized mixed equilibrium problems, finitely many variational inequalities, the general system of variational inequalities and the fixed point problem of an asymptotically strict pseudocontractive mapping in the intermediate sense in a real Hilbert space. We prove strong convergence theorem for the iterative algorithm under suitable conditions. On the other hand, we also propose another iterative algorithm by hybrid shrinking projection method for finding a fixed point of infinitely many nonexpansive mappings with the same constraints, and derive its strong convergence under mild assumptions.
Energy Technology Data Exchange (ETDEWEB)
Pereira, Milton A.P. [School of Chemical Engineering, State University of Campinas, P.O. Box 6066, Campinas-SP 13081-970 (Brazil); Aznar, Martin [School of Chemical Engineering, State University of Campinas, P.O. Box 6066, Campinas-SP 13081-970 (Brazil)]. E-mail: maznar@feq.unicamp.br
2006-01-15
(Liquid + liquid) equilibrium data for the quaternary systems (water + tert-butanol + 1-butanol + KBr) and (water + tert-butanol + 1-butanol + MgCl{sub 2}) were experimentally determined at T = 293.15 K and T = 313.15 K. For mixtures with KBr, the overall salt concentrations were 5 and 10 mass percent; for mixtures with MgCl{sub 2}, the overall salt concentrations were 2 and 5 mass percent. The experimental results were used to estimate molecular interaction parameters for the NRTL activity coefficient model, using the Simplex minimization method and a concentration-based objective function. The correlation results are extremely satisfactory, with deviations in phase compositions below 1.7%.
Tetrisyanda, Rizky; Kuswandi, Wibawa, Gede
2017-01-01
To obtain a high purity of clove oil, it is needed to separate β-caryophyllene from the oil mixtures.The separation of this component could be obtained by solvent extraction. In this work, liquid-liquid equilibrium (LLE) data were measured for the ternary system of water β-caryophyllene (1) + 2-propanol (2) + water (3) at temperature 303.15 K, 313.15 K and 323.15K under atmospheric pressure. The experimental LLE data were correlated with the NRTL and UNIQUAC models. The reliability of these models is tested by comparison with experimental results. The varied temperatures studied in this work have significant influence to the two-phase area and the solubility of 2-propanol and β-caryophyllene in the aqueous phase.
Self-organizing dynamic stability of far-from-equilibrium biological systems
Ivanitskii, G. R.
2017-10-01
One indication of the stability of a living system is the variation of the system’s characteristic time scales. Underlying the stability mechanism are the structural hierarchy and self-organization of systems, factors that give rise to a positive (accelerating) feedback and a negative (braking) feedback. Information processing in the brain cortex plays a special role in highly organized living organisms.
Olmos, Beatriz; Lesanovsky, Igor; Garrahan, Juan P
2014-10-01
We explore the relaxation dynamics of quantum many-body systems that undergo purely dissipative dynamics through non-classical jump operators that can establish quantum coherence. Our goal is to shed light on the differences in the relaxation dynamics that arise in comparison to systems evolving via classical rate equations. In particular, we focus on a scenario where both quantum and classical dissipative evolution lead to a stationary state with the same values of diagonal or "classical" observables. As a basis for illustrating our ideas we use spin systems whose dynamics becomes correlated and complex due to dynamical constraints, inspired by kinetically constrained models (KCMs) of classical glasses. We show that in the quantum case the relaxation can be orders of magnitude slower than the classical one due to the presence of quantum coherences. Aspects of these idealized quantum KCMs become manifest in a strongly interacting Rydberg gas under electromagnetically induced transparency (EIT) conditions in an appropriate limit. Beyond revealing a link between this Rydberg gas and the rather abstract dissipative KCMs of quantum glassy systems, our study sheds light on the limitations of the use of classical rate equations for capturing the non-equilibrium behavior of this many-body system.
Evaluation of a Passive Heat Exchanger Based Cooling System for Fuel Cell Applications
Colozza, Anthony J.; Burke, Kenneth A.
2011-01-01
Fuel cell cooling is conventionally performed with an actively controlled, dedicated coolant loop that exchanges heat with a separate external cooling loop. To simplify this system the concept of directly cooling a fuel cell utilizing a coolant loop with a regenerative heat exchanger to preheat the coolant entering the fuel cell with the coolant exiting the fuel cell was analyzed. The preheating is necessary to minimize the temperature difference across the fuel cell stack. This type of coolant system would minimize the controls needed on the coolant loop and provide a mostly passive means of cooling the fuel cell. The results indicate that an operating temperature of near or greater than 70 C is achievable with a heat exchanger effectiveness of around 90 percent. Of the heat exchanger types evaluated with the same type of fluid on the hot and cold side, a counter flow type heat exchanger would be required which has the possibility of achieving the required effectiveness. The number of heat transfer units required by the heat exchanger would be around 9 or greater. Although the analysis indicates the concept is feasible, the heat exchanger design would need to be developed and optimized for a specific fuel cell operation in order to achieve the high effectiveness value required.
Power-law Growth and Punctuated Equilibrium Dynamics in Water Resources Systems
Parolari, A.; Katul, G. G.; Porporato, A. M.
2015-12-01
The global rise in population-driven water scarcity and recent appreciation of strong dynamic coupling between human and natural systems has called for new approaches to predict the future sustainability of regional and global water resources systems. The dynamics of coupled human-water systems are driven by a complex set of social, environmental, and technological factors. Present projections of water resources systems range from a finite carrying capacity regulated by accessible freshwater, or `peak renewable water,' to punctuated evolution with new supplied and improved efficiency gained from technological and social innovation. However, these projections have yet to be quantified from observations or in a comprehensive theoretical framework. Using data on global water withdrawals and storage capacity of regional water supply systems, non-trivial dynamics are identified in water resources systems development over time, including power-law growth and punctuated equilibria. Two models are introduced to explain this behavior: (1) a delay differential equation and (2) a power-law with log-periodic oscillations, both of which rely on past conditions (or system memory) to describe the present rate of growth in the system. In addition, extension of the first model demonstrates how system delays and punctuated equilibria can emerge from coupling between human population growth and associated resource demands. Lastly, anecdotal evidence is used to demonstrate the likelihood of power-law growth in global water use from the agricultural revolution 3000 BC to the present. In a practical sense, the presence of these patterns in models with delayed oscillations suggests that current decision-making related to water resources development results from the historical accumulation of resource use decisions, technological and social changes, and their consequences.
Real time alert system: a disease management system leveraging health information exchange.
Anand, Vibha; Sheley, Meena E; Xu, Shawn; Downs, Stephen M
2012-01-01
Rates of preventive and disease management services can be improved by providing automated alerts and reminders to primary care providers (PCPs) using of health information technology (HIT) tools. Using Adaptive Turnaround Documents (ATAD), an existing Health Information Exchange (HIE) infrastructure and office fax machines, we developed a Real Time Alert (RTA) system. RTA is a computerized decision support system (CDSS) that is able to deliver alerts to PCPs statewide for recommended services around the time of the patient visit. RTA is also able to capture structured clinical data from providers using existing fax technology. In this study, we evaluate RTA's performance for alerting PCPs when their patients with asthma have an emergency room visit anywhere in the state. Our results show that RTA was successfully able to deliver "just in time" patient-relevant alerts to PCPs across the state. Furthermore, of those ATADs faxed back and automatically interpreted by the RTA system, 35% reported finding the provided information helpful. The PCPs who reported finding information helpful also reported making a phone call, sending a letter or seeing the patient for follow up care. We have successfully demonstrated the feasibility of electronically exchanging important patient related information with the PCPs statewide. This is despite a lack of a link with their electronic health records. We have shown that using our ATAD technology, a PCP can be notified quickly of an important event such as a patient's asthma related emergency room admission so further follow up can happen in near real time.
Heat exchangers for cardioplegia systems: in vitro study of four different concepts.
Drummond, Mário; Novello, Waldyr Parorali; de Arruda, Antonio Celso Fonseca; Braile, Domingo Marcolino
2003-05-01
The aim of this work is the evaluation of four different heat exchangers used for myocardium during cardioplegic system in cardiac surgeries. Four types of shell and tube heat exchangers made of different exchange elements were constructed, as follows: stainless steel tubes, aluminium tubes, polypropylene hollow fiber, and bellows type. The evaluation was performed by in vitro tests of parameters such as heat transfer, pressure drop, and hemolysis tendency. The result has shown that all four systems tested were able to achieve the heat performance, and to offer low resistance to flow, and safety, as well as have low tendency to hemolysis. However, we can emphasize that the bellows type heat exchanger has a significant difference with regard to the other three types.
Advanced Heat/Mass Exchanger Technology for Geothermal and Solar Renewable Energy Systems
Energy Technology Data Exchange (ETDEWEB)
Greiner, Miles [Univ. of Nevada, Reno, NV (United States); Childress, Amy [Univ. of Nevada, Reno, NV (United States); Hiibel, Sage [Univ. of Nevada, Reno, NV (United States); Kim, Kwang [Univ. of Nevada, Reno, NV (United States); Park, Chanwoo [Univ. of Nevada, Reno, NV (United States); Wirtz, Richard [Univ. of Nevada, Reno, NV (United States)
2014-12-16
Northern Nevada has abundant geothermal and solar energy resources, and these renewable energy sources provide an ample opportunity to produce economically viable power. Heat/mass exchangers are essential components to any energy conversion system. Improvements in the heat/mass exchange process will lead to smaller, less costly (more efficient) systems. There is an emerging heat transfer technology, based on micro/nano/molecular-scale surface science that can be applied to heat/mass exchanger design. The objective is to develop and characterize unique coating materials, surface configurations and membranes capable of accommodating a 10-fold increase in heat/mass exchanger performance via phase change processes (boiling, condensation, etc.) and single phase convective heat/mass transfer.
21 CFR 26.41 - Exchange and endorsement of quality system evaluation reports.
2010-04-01
... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Exchange and endorsement of quality system... DEVICE QUALITY SYSTEM AUDIT REPORTS, AND CERTAIN MEDICAL DEVICE PRODUCT EVALUATION REPORTS: UNITED STATES... endorsement of quality system evaluation reports. (a) Listed European Community (EC) conformity assessment...
An Approach to Semantic Interoperability for Improved Capability Exchanges in Federations of Systems
Moschoglou, Georgios
2013-01-01
This study seeks an affirmative answer to the question whether a knowledge-based approach to system of systems interoperation using semantic web standards and technologies can provide the centralized control of the capability for exchanging data and services lacking in a federation of systems. Given the need to collect and share real-time…
Staff exchange with Viatex-Recovery Systems, Inc.. Final project report
Energy Technology Data Exchange (ETDEWEB)
Jones, E.O. [Pacific Northwest Lab., Richland, WA (United States); Kensington, K.L. [Viatec, Inc., Hastings, MI (United States)
1994-03-01
The purpose of this industrial staff exchange is to assist the license, Viatec, Inc., in commercializing the Waste Acid Detoxification and Reclamation (WADR) process system. The process system was developed at the Pacific Northwest Laboratory (PNL) which is a DOE national laboratory. The objective of the activity is to establish a successful local business to design, build, and manufacture WARD process systems.
ASN.1 notation for exchange of data in computer-based railway control systems
Directory of Open Access Journals (Sweden)
Zbigniew ŁUKASIK
2009-01-01
Full Text Available Development of railway control systems aims at computerization. In most cases these systems are Distributed Real Time Systems. However, a huge problem in their putting into practice is the lack of interface standardization in the range of data structures and information exchange methods. It results in a variety of solutions, and thus in problems concerning cooperation of systems that come from different software vendors. Specification of protocols for data exchanging applications should therefore be created with the use of generally accepted standards. One of them is ASN.1 (Abstract Syntax Notation One language, which shall be presented in this article.
DEFF Research Database (Denmark)
Awan, Javeed A.; Coquelet, Christophe; Tsivintzelis, Ioannis
2016-01-01
New vapor-liquid equilibrium (VLE) data for 1-propanethiol + 1-butanethiol + CH4 ternary system is reported. Measurements were performed at three different temperatures (303, 336, and 368 K), and the pressure ranged from 1 to 9 MPa. The total system pressure was maintained by CH4. The inlet mole...
Dehumidification performance investigation of run-around membrane energy exchanger system
Directory of Open Access Journals (Sweden)
Kassai Miklos
2016-01-01
Full Text Available Liquid-to-air membrane energy exchanger is a novel membrane base energy exchanger, which allows both heat and moisture transfer between air and a salt solution. It uses semi-permeable membrane to eliminate entrainment of liquid desiccant as aerosols in air stream and allow simultaneous heat and moisture transfer between salt solution flow and airflow. The heat and mass transfer performance of a single liquid-to-air membrane energy exchanger is significantly dependent on two dimensionless parameters. They are the number of heat transfer units (NTU and the ratio of heat capacity rates between solution flow and air flow (Cr*. The liquid-to-air membrane energy exchangers can also be applied in a run-around membrane energy exchanger system, which is mainly comprised of two liquid-to-air membrane energy exchangers and a closed loop of aqueous desiccant solution and used as a passive energy recovery system to recover the energy (both heat and moisture from the exhaust air to precondition the supply air in air conditioning systems. In this study the dehumidification capacity of a run-around membrane energy exchanger is investigated numerically at different exhaust air temperatures and Cr* values. Increasing the exhaust air temperature or the Cr* would enhance the dehumidification capacity of the a run-around membrane energy exchanger system under Cr*≤1, but the improvement is limited. The dehumidification capacity at low Cr* is much lower than that under the optimal Cr* value (Cr*=3.2 where the maximum latent effectiveness is obtained.
Nanofiltration: ion exchange system for effective surfactant removal from water solutions
Kowalska, I.
2014-01-01
A system combining nanofiltration and ion exchange for highly effective separation of anionic surfactant from water solutions was proposed. The subjects of the study were nanofiltration polyethersulfone membranes and ion-exchange resins differing in type and structure. The quality of the treated solution was affected by numerous parameters, such as quality of the feed solution, membrane cut-off, resin type, dose and the solution contact time with the resin. A properly designed purification sy...
Equilibrium of a system of superconducting rings in a uniform gravitational field
Bishaev, A. M.; Bush, A. A.; Gavrikov, M. B.; Gordeev, I. S.; Denisyuk, A. I.; Kamentsev, K. E.; Kozintseva, M. V.; Savel'ev, V. V.; Sigov, A. S.
2013-05-01
To construct a plasma trap with levitating magnetic coils in the thin ring approximation, we derive the expression for the potential energy of a system of several superconducting rings (one of which is fixed) capturing the preset flows in the uniform gravitational field as a function of the coordinates of the free ring (or rings). Calculations performed in the Mathcad system show that the potential energy of such a system has a local minimum for certain values of parameters. Stable levitation of a superconducting ring in the position corresponding to calculations is realized in the field of another superconducting ring, and this leads to the conclusion that a magnetic Galatea trap can be prepared on the basis of a levitating quadrupole.
Directory of Open Access Journals (Sweden)
Ruberlan Gomes da Silva
2017-01-01
Full Text Available Chemical fertilizers, such as potassium chloride, ammonium nitrate and other chemical products like sodium hydroxide and soda ash are produced from electrolyte solutions or brines with a high content of soluble salts. Some of these products are manufactured by fractional crystallization, when several salts are separated as solid phases with high purity (>90%. Due to the large global demand for potassium fertilizers, a good knowledge about the compositions of salts and brines is helpful to design an effective process. A thermodynamic model based on Pitzer and Harvie's model was used to predict the composition of crystallized salts after water removal by forced evaporation and cooling from multicomponent solutions or brines. Initially, the salts’ solubilities in binary systems (NaCl–H2O, KCl–H2O and MgCl2–H2O and ternary system (KCl–MgCl2–H2O were calculated at 20 °C and compared with literature data. Next, the model was compared to our experimental data on the quinary system NaCl–KCl–MgCl2–CaCl2–H2O system at 20 °C. The Pitzer and Harvie's model represented well both the binary and ternary systems. Besides, for the quinary system the fit was good for brine densities up to 1350 kg/m3. The models were used to estimate the chemical composition of the solutions and salts produced by fractional crystallization and in association with material balance to respond to issues related to the production rates in a solar pond containing several salts dissolved, for instance, NaCl, KCl, MgCl2 and CaCl2.
A Computer Aided System for Correlation and Prediction of Phase Equilibrium Data
DEFF Research Database (Denmark)
Nielsen, T.L.; Gani, Rafiqul
2001-01-01
based on mathematical programming. This paper describes the development of a computer aided system for the systematic derivation of appropriate property models to be used in the service role for a specified problem. As a first step, a library of well-known property models ha's been developed...
Equilibrium thermodynamics of the ternary membrane-forming system nylon, formic acid and water
Bulte, A.M.W.; Bulte, A.M.W.; Naafs, E.M.; van Eeten, F.; Mulder, M.H.V.; Smolders, C.A.; Smolders, C.A.; Strathmann, H.
1996-01-01
The binary Flory-Huggins interaction parameters for the ternary membrane-forming system nylon, formic acid and water have been obtained from literature data, swelling values and melting point depression. Nylon 4,6 nylon 6 and a copolymer of nylon 4,6 and 6 were examined. The isothermal
Experimental study and phase equilibrium modeling of systems containing acid gas and glycol
DEFF Research Database (Denmark)
Afzal, Waheed; Breil, Martin P.; Tsivintzelis, Ioannis
2012-01-01
In this work, we study phase equilibria of systems containing acid gases and glycols. The acid gases include carbonyl sulfide (COS), hydrogen sulfide (H2S), and carbon dioxide (CO2) while glycols include monoethylene glycol (MEG), diethylene glycol (DEG), and triethylene glycol (TEG). A brief lit...
Directory of Open Access Journals (Sweden)
T. A. Kuchmenko
2013-01-01
Full Text Available In the article discussed the possibility of blood sample’s assessment with the following diagnostic characteristics: "endometriosis", "fibroids", "uterine body cancer" by the signals of multisensor system. It has been found that blood samples can be reliably ranking into groups according to their diagnostic characteristics using the geometry, square of "visual prints" and the sorption effectiveness parameters max ij А.
An exchange format for use-cases of hospital information systems.
Masuda, G; Sakamoto, N; Sakai, R; Yamamoto, R
2001-01-01
Object-oriented software development is a powerful methodology for development of large hospital information systems. We think use-case driven approach is particularly useful for the development. In the use-cases driven approach, use-cases are documented at the first stage in the software development process and they are used through the whole steps in a variety of ways. Therefore, it is important to exchange and share the use-cases and make effective use of them through the overall lifecycle of a development process. In this paper, we propose a method of sharing and exchanging use-case models between applications, developers, and projects. We design an XML based exchange format for use-cases. We then discuss an application of the exchange format to support several software development activities. We preliminarily implemented a support system for object-oriented analysis based on the exchange format. The result shows that using the structural and semantic information in the exchange format enables the support system to assist the object-oriented analysis successfully.
Causality and non-equilibrium second-order phase transitions in inhomogeneous systems.
del Campo, A; Kibble, T W B; Zurek, W H
2013-10-09
When a second-order phase transition is crossed at a finite rate, the evolution of the system stops being adiabatic as a result of the critical slowing down in the neighborhood of the critical point. In systems with a topologically nontrivial vacuum manifold, disparate local choices of the ground state lead to the formation of topological defects. The universality class of the transition imprints a signature on the resulting density of topological defects: it obeys a power law in the quench rate, with an exponent dictated by a combination of the critical exponents of the transition. In inhomogeneous systems the situation is more complicated, as the spontaneous symmetry breaking competes with bias caused by the influence of the nearby regions that already chose the new vacuum. As a result, the choice of the broken symmetry vacuum may be inherited from the neighboring regions that have already entered the new phase. This competition between the inherited and spontaneous symmetry breaking enhances the role of causality, as the defect formation is restricted to a fraction of the system where the front velocity surpasses the relevant sound velocity and phase transition remains effectively homogeneous. As a consequence, the overall number of topological defects can be substantially suppressed. When the fraction of the system is small, the resulting total number of defects is still given by a power law related to the universality class of the transition, but exhibits a more pronounced dependence on the quench rate. This enhanced dependence complicates the analysis but may also facilitate experimental testing of defect formation theories.
DEFF Research Database (Denmark)
Awan, Javeed A.; Coquelet, Christophe; Tsivintzelis, Ioannis
2016-01-01
New vapor-liquid equilibrium (VLE) data for 1-propanethiol + 1-butanethiol + CH4 ternary system is reported. Measurements were performed at three different temperatures (303, 336, and 368 K), and the pressure ranged from 1 to 9 MPa. The total system pressure was maintained by CH4. The inlet mole...... fraction of 1-propanethiol (x = 5.43 x 10-1) and 1-butanethiol (x = 4.56 x 10-1) in the liquid phase were same in all experiments. A static analytic method was used for performing phase equilibrium measurements. The new VLE data have been modeled successfully with cubic-plus-association (CPA) equation...
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
Tarquini, Simone
2017-08-01
A simple formula relates lava discharge rate to the heat radiated per unit time from the surface of active lava flows (the "thermal proxy"). Although widely used, the physical basis of this proxy is still debated. In the present contribution, lava flows are approached as open, dissipative systems that, under favorable conditions, can attain a non-equilibrium stationary state. In this system framework, the onset, growth, and demise of lava flow units can be explained as a self-organization phenomenon characterized by a given temporal frequency defined by the average life span of active lava flow units. Here, I review empirical, physical, and experimental models designed to understand and link the flow of mass and energy through a lava flow system, as well as measurements and observations that support a "real-world" view. I set up two systems: active lava flow system (or ALFS) for flowing, fluid lava and a lava deposit system for solidified, cooling lava. The review highlights surprising similarities between lava flows and electric currents, which typically work under stationary conditions. An electric current propagates almost instantaneously through an existing circuit, following the Kirchhoff law (a least dissipation principle). Flowing lavas, in contrast, build up a slow-motion "lava circuit" over days, weeks, or months by following a gravity-driven path down the steepest slopes. Attainment of a steady-state condition is hampered (and the classic thermal proxy does not hold) if the supply stops before completion of the "lava circuit." Although gravity determines initial flow path and extension, the least dissipation principle means that subsequent evolution of mature portions of the active lava flow system is controlled by increasingly insulated conditions.
Fluctuations of energy flux in a simple dissipative out-of-equilibrium system
Falcón, Claudio; Falcon, Eric
2009-04-01
We report the statistical properties of the fluctuations of the energy flux in an electronic RC circuit driven with a stochastic voltage. The fluctuations of the power injected in the circuit are measured as a function of the damping rate and the forcing parameters. We show that its distribution exhibits a cusp close to zero and two asymmetric exponential tails, with the asymmetry being driven by the mean dissipation. This simple experiment allows one to capture the qualitative features of the energy flux distribution observed in more complex dissipative systems. We also show that the large fluctuations of injected power averaged on a time lag do not verify the fluctuation theorem even for long averaging time. This is in contrast to the findings of previous experiments due to their small range of explored fluctuation amplitude. The injected power in a system of N components either correlated or not is also studied to mimic systems with large number of particles, such as in a dilute granular gas.
MODELING OF AN ADVANCED HEAT EXCHANGE UNIT WITH MICROCHANNELS FOR A COMBINED PHOTOENERGY SYSTEM
Directory of Open Access Journals (Sweden)
R. V. Zaitsev
2017-06-01
Full Text Available Purpose. Mathematical modeling of the heat exchange unit main parameters for photoenergy system based on general models with forced circulation of heat transfer fluid. Methodology. To determine the coefficient of heat transfer at a given coolant temperature and surfaces temperature necessary to determine the temperature gradient in the wall of the heat exchanger. Temperature gradients can be determined by solving the equation of energy, which depends on the distribution of the flow rate in the flow. In general, a solution of convective heat transfer fluid to flow along the plane comes to solution of the system of differential equations. Results. In the paper features of the selection of theoretical basis and mathematical modeling of thermal processes in the heat exchange unit for combination photoenergy system are presented. As a result of the simulation conducted we improve and develop high-efficiency heat exchange unit with microchannels. Testing of the proposed unit proved its high efficiency through the implementation of turbulent flow of coolant with heat transfer coefficient at 18 kW/(m2×K. Analytical testing of the heat exchanger allowed showing that heat exchanger unit provides a stable operating temperature at less than 50 °C with the coolant flow rate is less than 0.3 m/s. Originality. Novelty of the proposed heat exchanger is in the optimal design of microchannels to improve the heat transfer coefficient. Practical value. The use of this heat exchanger will improve the quality and uniformity of cooling solar panels and reduce energy costs for circulation of fluid.
Directory of Open Access Journals (Sweden)
MELO S. A. B. VIEIRA DE
1999-01-01
Full Text Available The feasibility of deterpenating orange peel oil with supercritical CO2 depends on relevant vapor-liquid equilibrium data because the selectivity of this solvent for limonene and linalool (the two key components of the oil is of crucial importance. The vapor-liquid equilibrium data of the CO2-limonene binary system was measured at 50, 60 and 70oC and pressures up to 10 MPa, and of the CO2-linalool binary system at 50oC and pressures up to 85 bar. These results were compared with published data when available in the literature. The unpublished ternary phase equilibrium of CO2-limonene-linalool was studied at 50oC and up to 9 MPa. Selectivities obtained using these ternary data were compared with those calculated using binary data and indicate that a selective separation of limonene and linalool can be achieved.
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…
Modeling of vapor-liquid-solid equilibrium in gas - aqueous electrolyte systems
DEFF Research Database (Denmark)
Thomsen, Kaj; Rasmussen, Peter
1999-01-01
A thermodynamic model for the description of vapor-liquid-solid equilibria is introduced. This model is a combination of the extended UNIQUAC model for electrolytes and the Soave-Redlich-Kwong cubic equation of state. The model has been applied to aqueous systems containing ammonia and/or carbon...... dioxide along with various salts. Model parameters valid in the temperature range 0-110 degrees C, the pressure range from 0-100 bar, and the concentration range up to approximately 80 molal ammonia are given. The model parameters were evaluated on the basis of more than 7000 experimental data points. (C...
Wysocka, Waleria; Brukwicki, Tadeusz; Włodarczak, Jacek
2012-06-01
On the basis of literature interpretation of 13C NMR and 1H NMR spectra of bis-quinolizidine alkaloids, the values of free enthalpy ΔG of conformational equilibria of those compounds were calculated. The results were analysed together with the X-ray and DFT data to discuss the effects of different substituents attached to the sparteine system in various positions as well as the effects of structural modifications on conformational equilibria. The measure of the effect was expressed by ΔΔG value, defined as the difference in ΔG of the compound under consideration and its parent compound without a given substituent.
Two simple systems with cold atoms: quantum chaos tests and non-equilibrium dynamics
Energy Technology Data Exchange (ETDEWEB)
Stone, Cavan; Aoud, Yassine Ait El; Olshanii, Maxim [Department of Physics, University of Massachusetts Boston, Boston MA 02125 (United States); Yurovsky, Vladimir A, E-mail: Maxim.Olshanii@umb.ed [School of Chemistry, Tel Aviv University, 69978 Tel Aviv (Israel)
2010-05-15
This paper is an attempt to establish a link between the quantum nonequilibrium dynamics of cold gases and 50 years of progress in low-dimensional quantum chaos. We identify two atomic systems lying in the interface: two interacting atoms in a harmonic multimode waveguide and an interacting two-component Bose-Bose mixture in a double-well potential. In particular, we study the level spacing distribution, the wavefunction statistics, the eigenstate thermalization and the ability to thermalize in a relaxation process as such.
Pudlak, M; Nazmitdinov, R G; Pincak, R
2011-01-01
Creation of electron or exciton by external fields in a system with initially statistically independent unrelaxed vibrational modes leads to an initial condition term. The contribution of this term in the time convolution generalized master equation approach is studied in second order of the perturbation theory for electron-phonon coupling in the parth integral formalism. The developed approach, applied for analysis of dynamics in the photosynthetic reaction center, exhibits the key role of the initial condition term at the primary stage of electron transfer.
Caliber approach for non-equilibrium systems with a small number of states
Schmit, Jeremy; Ghosh, Kingshuk; Dill, Ken
2008-03-01
We present a theory for the dynamics of systems with a small number of states based on E.T. Jaynes' principle of Maximum Caliber. We construct the full dynamical partition function using a transfer matrix formalism with the transition rates as input parameters. Using this partition function, we are able to calculate all moments of dynamical quantities, and thus are able to predict fluctuations around the average behavior. We compare our results to single molecule and microfluidics experiments and contrast our results to the predictions of Minimum Entropy Production.
Development of a Waste Water Regenerative System - Using Sphagnum Moss Ion-exchange
McKeon, M.; Wheeler, R.; Leahy, Jj
The use of inexpensive, light weight and regenerative systems in an enclosed environment is of great importance to sustained existence in such habitats as the International Space Station, Moon or even Mars. Many systems exist which utilise various synthetic ion exchangers to complete the process of waste water clean-up. These systems do have a very good exchange rate for cations but a very low exchange rate for anions. They also have a maximum capacity before they need regeneration. This research proposes a natural alternative to these synthetic ion-exchangers that utilises one of natures greatest ion-exchangers, that of Sphagnum Moss. Sphagna can be predominantly found in the nutrient poor environment of Raised Bogs, a type of isolated wetland with characteristic low pH and little interaction with the surrounding water table. All nutrients come from precipitation. The sphagna have developed as the bog's sponges, soaking up all available nutrients (both cation & anion) from the precipitation and eventually distributing them to the surrounding flora and fauna, through the water. The goal of this research is to use this ability in the processing of waste water from systems similar to isolated microgravity environments, to produce clean water for reuse in these environments. The nutrients taken up by the sphagna will also be utilised as a growth medium for cultivar growth, such as those selected for hydroponics' systems.
Compact interior heat exchangers for CO{sub 2} mobile heat pumping systems
Energy Technology Data Exchange (ETDEWEB)
Hafner, Armin
2003-07-01
The natural refrigerant carbon dioxide (CO{sub 2}) offers new possibilities for design of flexible, efficient and environmentally safe mobile heat pumping systems. As high-efficient car engines with less waste heat are developed, extra heating of the passenger compartment is needed in the cold season. A reversible transcritical CO{sub 2} system with gliding temperature heat rejection can give high air delivery temperature which results in rapid heating of the passenger compartment and rapid defogging or defrosting of windows. When operated in cooling mode, the efficiency of transcritical CO{sub 2} systems is higher compared to common (HFC) air conditioning systems, at most dominant operating conditions. Several issues were identified for the design of compact interior heat exchangers for automotive reversible CO{sub 2} heat pumping systems. Among theses issues are: (1) Refrigerant flow distribution, (2) Heat exchanger fluid flow circuiting, (3) Air temperature uniformity downstream of the heat exchanger, (4) Minimization of temperature approach, (5) Windshield flash fogging due to retained water inside the heat exchanger, (6) Internal beat conduction in heating mode operation, and (7) Refrigerant side pressure drop In order to provide a basis for understanding these issues, the author developed a calculation model and set up a test facility and investigated different prototype heat exchangers experimentally.
Solid Phase Equilibrium Relations in the CaO-SiO2-Nb2O5-La2O3 System at 1273 K
Qiu, Jiyu; Liu, Chengjun
2017-12-01
Silicate slag system with additions Nb and RE formed in the utilization of REE-Nb-Fe ore deposit resources in China has industrial uses as a metallurgical slag system. The lack of a phase diagram, theoretical, and thermodynamic information for the multi-component system restrict the comprehensive utilization process. In the current work, solid phase equilibrium relations in the CaO-SiO2-Nb2O5-La2O3 quaternary system at 1273 K (1000 °C) were investigated experimentally by the high-temperature equilibrium experiment followed by X-ray diffraction, scanning electron microscope, and energy dispersive spectrometer. Six spatial independent tetrahedron fields in the CaO-SiO2-Nb2O5-La2O3 system phase diagram were determined by the Gibbs Phase Rule. The current work combines the mass fraction of equilibrium phase and corresponding geometric relation. A determinant method was deduced to calculate the mass fraction of equilibrium phase in quaternary system according to the Mass Conservation Law, the Gibbs Phase Rule, the Lever's Rule, and the Cramer Law.
He, Feng
The phase equilibrium, viscosity of melt-quenched glasses, and processing of sol-gel glasses of the alumina-silica-lanthanum phosphate system were studied. These investigations were directed towards serving the objective of synthesizing nano-structured ceramic-matrix-composites via controlled crystallization of glass precursors. The thermal stability, phase equilibrium, and liquidus temperatures of the alumina- and mullite-lanthanum phosphate systems are determined. An iridium wire heater was constructed to anneal samples up to 2200°C. Phosphorus evaporation losses were significant at high temperatures, especially over 1800°C. The tentative phase diagrams of the two quasi-binary systems were presented. The viscosity of the melt-quenched mullite-lanthanum phosphate glasses was measured by three different methods, including viscous sintering of glass powder compacts, neck formation between two Frenkel glass beads, and thermal analysis of the glass transition. Improved methodologies were developed for applying the interpretative mathematical models to the results of the sintered powder and thermal analytical experiments. Good agreement was found between all three methods for both absolute values and temperature dependence. A sol-gel process was developed as a low temperature route to producing glasses. A unique, single phase mullite gel capable of low temperature (575°C) mullitization was made from tetraethoxysilane and aluminum isopropoxide at room temperature in three days. Low temperature crystallization was attributed to the avoidance of phase segregation during gel formation and annealing. This was greatly enhanced by a combination of low temperature preheating in the amorphous state, a high heating rate during crystallization and low water content. The Al2O3 content in mullite (61-68 mol%) depended on the highest annealing temperature. Two mullite-lanthanum phosphate gels were made based upon modifying the chemical procedures used for the homogeneous single
The evolutionary synchronization of the exchange rate system in ASEAN+6
Feng, Xiaobing; Hu, Haibo; Wang, Xiaofan
2010-12-01
Although there are extensive researches on the behavior of the world currency network, the complexity of the Asian regional currency system is not well understood regardless of its importance. Using daily exchange rates this paper examines exchange rate co-movements in the region before and after the China exchange rate reform. It was found that the correlation between Asian currencies and the US Dollar, the previous regional key currency has become weaker and intra-Asia interactions have increased. Cross sample entropy and cross entropy approaches are also applied to examine the synchrony behavior among the Asian currencies. The study also shows that the Asian exchange rate markets featured are neither stochastic nor efficient. These findings may shed some light on the in-depth understanding of collective behaviors in a regional currency network; they will also lay a theoretical foundation for further policy formulation in Asian currency integration.
A unified approach to equilibrium statistics in closed systems with random dynamics
Biró, Tamás S
2016-01-01
In a balanced version of decay and growth processes a simple master equation arrives at a final state including the Poisson, Bernoulli, negative binomial and P\\'olya distribution. Such decay and growth rates incorporate a symmetry between the observed subsystem and the rest of a total system with fixed total number of states, K, and occupation numbers N. We give both a complex network and a particle production dynamics interpretation. For networks we follow the evolution of the degree distribution, P(n), in a directed network where a node can activate k fixed connections from K possible partnerships among all nodes while n is a random variable counting the links per node, and N is the total number of connections, which is also fixed. For particle physics problems P(n) is the probability of having n particles (or other quanta) distributed among k states (phase space cells) while altogether a fixed number of N particles reside on K states.
Yeung, Jason; Sivarajan, S; Treibel, T A; Rosmini, S; Fontana, M; Gillmore, J D; Hawkins, P N; Punwani, S; Moon, J C; Taylor, S A; Bandula, S
2017-11-01
To investigate equilibrium contrast-enhanced CT (EQ-CT) measurement of extracellular volume fraction (ECV) in patients with systemic amyloid light-chain (AL) amyloidosis, testing the hypothesis that ECV becomes elevated in the liver and spleen and ECV correlates with other estimates of organ amyloid burden. 26 patients with AL amyloidosis underwent EQ-CT, and ECV was measured in the liver and spleen. Patients also underwent serum amyloid P (SAP) component scintigraphy with grading of liver and spleen involvement. Mann-Whitney U test was used to test for a difference between patients with amyloid deposition (SAP grade 1-3) and those without (SAP grade 0). Variation in ECV across SAP grades was assessed using the Kruskal-Wallis test and association between ECV and SAP grades with Spearman correlation. Mean ECV in the spleen and liver was significantly greater (p ECV increased with increasing amyloid burden, showing positive correlation with SAP grade in both the liver (r = 0.758) and spleen (r = 0.867). In patients with systemic AL amyloidosis, EQ-CT can demonstrate increased spleen and liver ECV, which is associated with amyloid disease burden.
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.
Prototype solar heated hot water systems and double-walled heat exchangers. Progress report
Energy Technology Data Exchange (ETDEWEB)
1978-10-01
A collection of quarterly and monthly reports from Elcam, Inc., covering progress made from January 1, 1978, through September 30, 1978, is presented. Elcam, is developing two solar-heated hot water prototype systems and two heat exchangers. This effort consists of development, manufacture, installation, maintenance, problem resolution, and system evaluation.
Barnes, Clarissa S.; Dunning, Johnna L.; Rehfeldt, Ruth Anne
2011-01-01
The picture exchange communication system (PECS) is a functional communication system frequently used with individuals diagnosed with autism spectrum disorders who experience severe language delays (Frost & Bondy, 2002). Few empirical investigations have evaluated strategies for training direct care staff how to effectively implement PECS with…
Rosales, Rocio; Stone, Karen; Rehfeldt, Ruth Anne
2009-01-01
The effectiveness of a behavioral skills training (BST) package to teach the implementation of the first three phases of the picture exchange communication system (PECS) was evaluated with 3 adults who had no history teaching any functional communication system. A multiple baseline design across participants was used to evaluate the effectiveness…
Energy Technology Data Exchange (ETDEWEB)
Pinto, Leandro F.; Segalen da Silva, Diogo Italo [Department of Chemical Engineering, Federal University of Parana, CEP 81531-990, Curitiba, PR (Brazil); Rosa da Silva, Fabiano; Ramos, Luiz P. [Department of Chemistry, Federal University of Parana, CEP 81531-990, Curitiba, PR (Brazil); Ndiaye, Papa M. [Department of Chemical Engineering, Federal University of Parana, CEP 81531-990, Curitiba, PR (Brazil); Corazza, Marcos L., E-mail: corazza@ufpr.br [Department of Chemical Engineering, Federal University of Parana, CEP 81531-990, Curitiba, PR (Brazil)
2012-01-15
Highlights: > We measured phase behavior for the system involving {l_brace}CO{sub 2} + biodiesel + methanol{r_brace}. > The saturation pressures were obtained using a variable-volume view cell. > The experimental data were modeled using PR-vdW2 and PR-WS equations of state. - Abstract: The main objective of this work was to investigate the high pressure phase behavior of the binary systems {l_brace}CO{sub 2}(1) + methanol(2){r_brace} and {l_brace}CO{sub 2}(1) + soybean methyl esters (biodiesel)(2){r_brace} and the ternary system {l_brace}CO{sub 2}(1) + biodiesel(2) + methanol(3){r_brace} were determined. Biodiesel was produced from soybean oil, purified, characterized and used in this work. The static synthetic method, using a variable-volume view cell, was employed to obtain the experimental data in the temperature range of (303.15 to 343.15) K and pressures up to 21 MPa. The mole fractions of carbon dioxide were varied according to the systems as follows: (0.2383 to 0.8666) for the binary system {l_brace}CO{sub 2}(1) + methanol(2){r_brace}; (0.4201 to 0.9931) for the binary system {l_brace}CO{sub 2}(1) + biodiesel(2){r_brace}; (0.4864 to 0.9767) for the ternary system {l_brace}CO{sub 2}(1) + biodiesel(2) + methanol(3){r_brace} with a biodiesel to methanol molar ratio of (1:3); and (0.3732 to 0.9630) for the system {l_brace}CO{sub 2} + biodiesel + methanol{r_brace} with a biodiesel to methanol molar ratio of (8:1). For these systems, (vapor + liquid), (liquid + liquid), (vapor + liquid + liquid) transitions were observed. The phase equilibrium data obtained for the systems were modeled using the Peng-Robinson equation of state with the classical van der Waals (PR-vdW2) and Wong-Sandler (PR-WS) mixing rules. Both thermodynamic models were able to satisfactorily correlate the phase behavior of the systems investigated and the PR-WS presented the best performance.
On the equilibrium morphology of systems drawn from spherical collapse experiments
Boily, C. M.; Athanassoula, E.
2006-06-01
We present a purely theoretical study of the morphological evolution of self-gravitating systems formed through the dissipationless collapse of N-point sources. We explore the effects of resolution in mass and length on the growth of triaxial structures formed by an instability triggered by an excess of radial orbits. We point out that as resolution increases, the equilibria shift, from mildly prolate, to oblate. A number of particles N ~= 100000 or larger is required for convergence of axial aspect ratios. An upper bound for the softening, ɛ ~ 1/256, is also identified. We then study the properties of a set of equilibria formed from scale-free cold initial mass distributions, ρ ~ r-γ 0 values of γ). We map the run of density in space and find no evidence for a power-law inner structure when γ violent relaxation for more peaked profiles when more phase mixing takes place at the centre. We map out the velocity field of the equilibria and note that at small radii the velocity coarse-grained distribution function (DF) is Maxwellian to a very good approximation. We extend our study to non-scale-free initial conditions and finite but subvirial kinetic energy. For cold collapses, the equilibria are again oblate, as the scale-free models. With increasing kinetic energy, the equilibria first shift to prolate morphology and then to spherical symmetry.
Zakhari, Monica E. A.; Anderson, Patrick D.; Hütter, Markus
2017-07-01
Open-porous deformable particles, often envisaged as sponges, are ubiquitous in biological and industrial systems (e.g., casein micelles in dairy products and microgels in cosmetics). The rich behavior of these suspensions is owing to the elasticity of the supporting network of the particle, and the viscosity of permeating solvent. Therefore, the rate-dependent size change of these particles depends on their structure, i.e., the permeability. This work aims at investigating the effect of the particle-size dynamics and the underlying particle structure, i.e., the particle permeability, on the transient and long-time behavior of suspensions of spongy particles in the absence of applied deformation, using the dynamic two-scale model developed by Hütter et al. [Farad. Discuss. 158, 407 (2012), 10.1039/c2fd20025b]. In the high-density limit, the transient behavior is found to be accelerated by the particle-size dynamics, even at average size changes as small as 1 % . The accelerated dynamics is evidenced by (i) the higher short-time diffusion coefficient as compared to elastic-particle systems and (ii) the accelerated formation of the stable fcc crystal structure. Furthermore, after long times, the particle-size dynamics of spongy particles is shown to result in lower stationary values of the energy and normal stresses as compared to elastic-particle systems. This dependence of the long-time behavior of these systems on the permeability, that essentially is a transport coefficient and hence must not affect the equilibrium properties, confirms that full equilibration has not been reached.
Rao, Wenwei; Wang, Yun; Han, Juan; Wang, Lei; Chen, Tong; Liu, Yan; Ni, Liang
2015-06-25
The cloud point of thermosensitive triblock polymer L61, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO), was determined in the presence of various electrolytes (K2HPO4, (NH4)3C6H5O7, and K3C6H5O7). The cloud point of L61 was lowered by the addition of electrolytes, and the cloud point of L61 decreased linearly with increasing electrolyte concentration. The efficacy of electrolytes on reducing cloud point followed the order: K3C6H5O7 > (NH4)3C6H5O7 > K2HPO4. With the increase in salt concentration, aqueous two-phase systems exhibited a phase inversion. In addition, increasing the temperature reduced the concentration of salt needed that could promote phase inversion. The phase diagrams and liquid-liquid equilibrium data of the L61-K2HPO4/(NH4)3C6H5O7/K3C6H5O7 aqueous two-phase systems (before the phase inversion but also after phase inversion) were determined at T = (25, 30, and 35) °C. Phase diagrams of aqueous two-phase systems were fitted to a four-parameter empirical nonlinear expression. Moreover, the slopes of the tie-lines and the area of two-phase region in the diagram have a tendency to rise with increasing temperature. The capacity of different salts to induce aqueous two-phase system formation was the same order as the ability of salts to reduce the cloud point.
Florentina A. Cziple
2006-01-01
The paper forwards the conclusions of a survey performed on a mathematical model of the phase equilibrium from the ternary system Al-Cu-Si. The author presents the calculus of the statistic equation of the liquidus surface model from this diagram, the plotting and statistical-mathematical interpretation of the results obtained.
Directory of Open Access Journals (Sweden)
Florentina A. Cziple
2006-10-01
Full Text Available The paper forwards the conclusions of a survey performed on a mathematical model of the phase equilibrium from the ternary system Al-Cu-Si. The author presents the calculus of the statistic equation of the liquidus surface model from this diagram, the plotting and statistical-mathematical interpretation of the results obtained.
Nishino, Masamichi; Miyashita, Seiji
2015-04-01
It is crucially important to investigate the effects of temperature on magnetic properties such as critical phenomena, nucleation, pinning, domain wall motion, and coercivity. The Landau-Lifshitz-Gilbert (LLG) equation has been applied extensively to study dynamics of magnetic properties. Approaches of Langevin noises have been developed to introduce the temperature effect into the LLG equation. To have the thermal equilibrium state (canonical distribution) as the steady state, the system parameters must satisfy some condition known as the fluctuation-dissipation relation. In inhomogeneous magnetic systems in which spin magnitudes are different at sites, the condition requires that the ratio between the amplitude of the random noise and the damping parameter depend on the magnitude of the magnetic moment at each site. Focused on inhomogeneous magnetic systems, we systematically showed agreement between the stationary state of the stochastic LLG equation and the corresponding equilibrium state obtained by Monte Carlo simulations in various magnetic systems including dipole-dipole interactions. We demonstrated how violations of the condition result in deviations from the true equilibrium state. We also studied the characteristic features of the dynamics depending on the choice of the parameter set. All the parameter sets satisfying the condition realize the same stationary state (equilibrium state). In contrast, different choices of parameter set cause seriously different relaxation processes. We show two relaxation types, i.e., magnetization reversals with uniform rotation and with nucleation.
Directory of Open Access Journals (Sweden)
Pessôa Filho P. A.
2004-01-01
Full Text Available Mixtures containing compounds that undergo hydrogen bonding show large deviations from ideal behavior. These deviations can be accounted for through chemical theory, according to which the formation of a hydrogen bond can be treated as a chemical reaction. This chemical equilibrium needs to be taken into account when applying stability criteria and carrying out phase equilibrium calculations. In this work, we illustrate the application of the stability criteria to establish the conditions under which a liquid-phase split may occur and the subsequent calculation of liquid-liquid equilibrium using a chemical-theory-modified Flory-Huggins equation to describe the non ideality of aqueous two-phase systems composed of poly(ethylene glycol and dextran. The model was found to be able to correlate ternary liquid-liquid diagrams reasonably well by simple adjustment of the polymer-polymer binary interaction parameter.
Recent trends in the development of heat exchangers for geothermal systems
Franco, A.; Vaccaro, M.
2017-11-01
The potential use of geothermal resources has been a remarkable driver for market players and companies operating in the field of geothermal energy conversion. For this reason, medium to low temperature geothermal resources have been the object of recent rise in consideration, with strong reference to the perspectives of development of Organic Rankine Cycle (ORC) technology. The main components of geothermal plants based on ORC cycle are surely the heat exchangers. A lot of different heat exchangers are required for the operation of ORC plants. Among those it is surely of major importance the Recovery Heat Exchanger (RHE, typically an evaporator), in which the operating fluid is evaporated. Also the Recuperator, in regenerative Organic Rankine Cycle, is of major interest in technology. Another important application of the heat exchangers is connected to the condensation, according to the possibility of liquid or air cooling media availability. The paper analyzes the importance of heat exchangers sizing and the connection with the operation of ORC power plants putting in evidence the real element of innovation: the consideration of the heat exchangers as central element for the optimum design of ORC systems.
Groenewald, Berlizé; Hetz, Stefan K; Chown, Steven L; Terblanche, John S
2012-07-01
Gas exchange dynamics in insects is of fundamental importance to understanding evolved variation in breathing patterns, such as discontinuous gas exchange cycles (DGCs). Most insects do not rely solely on diffusion for the exchange of respiratory gases but may also make use of respiratory movements (active ventilation) to supplement gas exchange at rest. However, their temporal dynamics have not been widely investigated. Here, intratracheal pressure, V(CO2) and body movements of the desert locust Schistocerca gregaria were measured simultaneously during the DGC and revealed several important aspects of gas exchange dynamics. First, S. gregaria employs two different ventilatory strategies, one involving dorso-ventral contractions and the other longitudinal telescoping movements. Second, although a true spiracular closed (C)-phase of the DGC could be identified by means of subatmospheric intratracheal pressure recordings, some CO(2) continued to be released. Third, strong pumping actions do not necessarily lead to CO(2) release and could be used to ensure mixing of gases in the closed tracheal system, or enhance water vapour reabsorption into the haemolymph from fluid-filled tracheole tips by increasing the hydrostatic pressure or forcing fluid into the haemocoel. Finally, this work showed that the C-phase of the DGC can occur at any pressure. These results provide further insights into the mechanistic basis of insect gas exchange.
Nanofiltration: ion exchange system for effective surfactant removal from water solutions
Directory of Open Access Journals (Sweden)
I. Kowalska
2014-12-01
Full Text Available A system combining nanofiltration and ion exchange for highly effective separation of anionic surfactant from water solutions was proposed. The subjects of the study were nanofiltration polyethersulfone membranes and ion-exchange resins differing in type and structure. The quality of the treated solution was affected by numerous parameters, such as quality of the feed solution, membrane cut-off, resin type, dose and the solution contact time with the resin. A properly designed purification system made it possible to reduce the concentration of anionic surfactant below 1 mg L-1 from feed solutions containing surfactant in concentrations above the CMC value.
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.
160 C PROTON EXCHANGE MEMBRANE (PEM) FUEL CELL SYSTEM DEVELOPMENT
Energy Technology Data Exchange (ETDEWEB)
L.G. Marianowski
2001-12-21
The objectives of this program were: (a) to develop and demonstrate a new polymer electrolyte membrane fuel cell (PEMFC) system that operates up to 160 C temperatures and at ambient pressures for stationary power applications, and (b) to determine if the GTI-molded composite graphite bipolar separator plate could provide long term operational stability at 160 C or higher. There are many reasons that fuel cell research has been receiving much attention. Fuel cells represent environmentally friendly and efficient sources of electrical power generation that could use a variety of fuel sources. The Gas Technology Institute (GTI), formerly Institute of Gas Technology (IGT), is focused on distributed energy stationary power generation systems. Currently the preferred method for hydrogen production for stationary power systems is conversion of natural gas, which has a vast distribution system in place. However, in the conversion of natural gas into a hydrogen-rich fuel, traces of carbon monoxide are produced. Carbon monoxide present in the fuel gas will in time cumulatively poison, or passivate the active platinum catalysts used in the anodes of PEMFC's operating at temperatures of 60 to 80 C. Various fuel processors have incorporated systems to reduce the carbon monoxide to levels below 10 ppm, but these require additional catalytic section(s) with sensors and controls for effective carbon monoxide control. These CO cleanup systems must also function especially well during transient load operation where CO can spike 300% or more. One way to circumvent the carbon monoxide problem is to operate the fuel cell at a higher temperature where carbon monoxide cannot easily adsorb onto the catalyst and poison it. Commercially available polymer membranes such as Nafion{trademark} are not capable of operation at temperatures sufficiently high to prevent this. Hence this project investigated a new polymer membrane alternative to Nafion{trademark} that is capable of operation at
Energy exchange in systems of particles with nonreciprocal interaction
Energy Technology Data Exchange (ETDEWEB)
Vaulina, O. S.; Lisina, I. I., E-mail: Irina.Lisina@mail.ru; Lisin, E. A. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)
2015-10-15
A model is proposed to describe the sources of additional kinetic energy and its redistribution in systems of particles with a nonreciprocal interaction. The proposed model is shown to explain the qualitative specific features of the dust particle dynamics in the sheath region of an RF discharge. Prominence is given to the systems of particles with a quasi-dipole–dipole interaction, which is similar to the interaction induced by the ion focusing effects that occur in experiments on a laboratory dusty plasma, and with the shadow interaction caused by thermophoretic forces and Le Sage’s forces.
Wu, Songgu; Feng, Fei; Zhou, Lina; Gong, Junbo
2012-09-01
Measurements of the metastable zone and solubility for flunixin meglumine-ethanol system were obtained. The solubility was measured within the temperature range from 288.15 to 328.15 K. The mole fraction solubility was correlated satisfactorily with the temperature by the equation: xeq=2.35×10-12e0.07121T. The value of enthalpy of dissolution, enthalpy of fusion and enthalpy of mixing were determined to be 49.04, 64.03 and -14.99 kJ mol-1 respectively. The metastable zone width of flunixin meglumine was measured by an electric conductivity method. A comparison of the nucleation temperatures from electric conductivity measurement and from focused beam reflectance measurement (FBRM) shows that both detection techniques give almost the same results for flunixin meglumine. The nucleation parameters of flunixin meglumine in ethanol were determined from the metastable zone data. Over the equilibrium temperature range from 312.28 to 325.55 K, the nucleation rate constant was varied from 0.00001 to 0.00120 #/m2 min, whereas the nucleation order was varied from 2.23022 to 3.39299. The obtained high values of nucleation order indicated a high rate of nucleation.
Directory of Open Access Journals (Sweden)
Maths Halstensen
2017-01-01
Full Text Available Liquid speciation is important for reliable process design and optimization of gas-liquid absorption process. Liquid-phase speciation methods are currently available, although they involve tedious and time-consuming laboratory work. Raman spectroscopy is well suited for in situ monitoring of aqueous chemical reactions. Here, we report on the development of a method for speciation of the CO2-NH3-H2O equilibrium using Raman spectroscopy and PLS-R modeling. The quantification methodology presented here offers a novel approach to provide rapid and reliable predictions of the carbon distribution of the CO2-NH3-H2O system, which may be used for process control and optimization. Validation of the reported speciation method which is based on independent, known, NH3-CO2-H2O solutions shows estimated prediction uncertainties for carbonate, bicarbonate, and carbamate of 6.45 mmol/kg H2O, 34.39 mmol/kg H2O, and 100.9 mmol/kg H2O, respectively.
Baldwin, Darryl Dean; Willi, Martin Leo; Fiveland, Scott Byron; Timmons, Kristine Ann
2010-12-14
A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.
Chun, Paul W.
2005-01-01
Applying the Planck-Benzinger methodology to biological systems, we have established that the negative Gibbs free energy minimum at a well-defined stable temperature, langTSrang, where the bound unavailable energy TΔS° = 0, has its origin in the sequence-specific hydrophobic interactions. Each such system we have examined confirms the existence of a thermodynamic molecular switch wherein a change of sign in [ΔCp°]reaction leads to a true negative minimum in the Gibbs free energy change of reaction, and hence a maximum in the related equilibrium constant, Keq. At this temperature, langTSrang, where ΔH°(TS)(-) = ΔG°(TS)(-)min, the maximum work can be accomplished in transpiration, digestion, reproduction or locomotion. In the human body, this temperature is 37°C. The langTSrang values may vary from one living organism to another, but the fact that the value of TΔS°(T) = 0 will not. There is a lower cutoff point, langThrang, where enthalpy is unfavorable but entropy is favorable, i.e. ΔH°(Th)(+) = TΔS°(Th)(+), and an upper limit, langTmrang, above which enthalpy is favorable but entropy is unfavorable, i.e. ΔH°(Tm)(-) = TΔS°(Tm)(-). Only between these two temperature limits, where ΔG°(T) = 0, is the net chemical driving force favorable for such biological processes as protein folding, protein-protein, protein-nucleic acid or protein-membrane interactions, and protein self-assembly. All interacting biological systems examined using the Planck-Benzinger methodology have shown such a thermodynamic switch at the molecular level, suggesting that its existence may be universal.
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 ...
A Novel RFID Sensing System Using Enhanced Surface Wave Technology for Battery Exchange Stations
Yeong-Lin Lai; Li-Chih Chang; Tai-Hwa Liu; Yi-Chun Sung; Cheng-Lun Yin
2014-01-01
This paper presents a novel radio-frequency identification (RFID) sensing system using enhanced surface wave technology for battery exchange stations (BESs) of electric motorcycles. Ultrahigh-frequency (UHF) RFID technology is utilized to automatically track and manage battery and user information without manual operation. The system includes readers, enhanced surface wave leaky cable antennas (ESWLCAs), coupling cable lines (CCLs), and small radiation patches (SRPs). The RFID sensing system ...
Energy Technology Data Exchange (ETDEWEB)
Sergey G Kalyakin; Andrey V Morozov; Oleg V Remizov; Alexandr A Tzyganok [State Scientific Center of Russian Federation - Institute for Physics and Power Engineering by A.I. Leypunsky, IPPE, 1, Bondarenko sq., Obninsk, 249030 (Russian Federation)
2005-07-01
Full text of publication follows: In the systems of passive reactor cooling and core reflooding from above under accident conditions, the cold water flows out into countercurrent steam flow; that is, the direct contact between steam and liquid occurs simultaneously over all cross-sections of pipes/closed spaces. The process is complicated by additional effect of steam condensation and droplet flow towards the steam flow. The processes of heat and mass transfer proceed simultaneously at variable liquid level. These factors give rise to a nonsteady, non-equilibrium two-phase flow. The operating conditions of such a non-steady process, the main of which being the time of closed water volume dump (or the flow coefficient), can be obtained only experimentally. The present work is devoted to the experimental investigations of the interaction of saturated steam with cold water at its flowing out from a closed space with a variable level and some characteristics of dynamic two-phase layer at the steam/liquid interface. With reference to the system of passive heat removal from VVER core, the processes of interaction of saturated steam, steam-water mixture, and air with cold water at its flowing out from a vertical plugged pipe with an internal diameter of 50 and 100 mm have been studied at a pressure of 0.5 MPa. It has been stated experimentally that the dump rate of subcooled water from a plugged pipe into steam is nearly an order of magnitude less than that into non-condensable gas media. The semi-empirical correlation describing the processes of water outflow from plugged pipes into steam is of the form of: W-bar = C{sub 0} {radical}(gd), where C{sub 0} is the dimensionless constant, d is the pipe internal diameter, m, g = 9.81 m/s{sup 2}. (authors)
Harmonised information exchange between decentralised food composition database systems
DEFF Research Database (Denmark)
Pakkala, Heikki; Christensen, Tue; Martínez de Victoria, Ignacio
2010-01-01
to those network nodes linked to the EuroFIR Web Services that will most likely have the requested information. The retrieved FCD are compiled into a specifically designed data interchange format (the EuroFIR Food Data Transport Package) in XML, which is sent back to the EuroFIR eSearch facility......Background/Objectives: The main aim of the European Food Information Resource (EuroFIR) project is to develop and disseminate a comprehensive, coherent and validated data bank for the distribution of food composition data (FCD). This can only be accomplished by harmonising food description and data...... documentation and by the use of standardised thesauri. Subjects/Methods: The data bank is implemented through a network of local FCD storages (usually national) under the control and responsibility of the local (national) EuroFIR partner. Results: The implementation of the system based on the Euro...
Windows-Yule, C. R. K.
2017-04-01
Driven granular media — assemblies of discrete, macroscopic elements exposed to a source of mechanical energy — represent inherently out-of-equilibrium systems. Although granular media are ubiquitous in both nature and industry, due to their dissipative nature and resultant complex behaviors they remain startlingly poorly understood as compared to classical, thermodynamic systems. Nonetheless, in recent years it has been observed that the behaviors of granular media can, under certain circumstances, closely resemble those of equilibrium systems. One of the most important contemporary questions in the field of granular physics is whether these similarities are merely superficial, or whether the parallels run deep enough that the behaviors of these nonequilibrium systems can in fact be successfully captured using analogs to existing theoretical models developed for classical systems. In this review, we draw together the findings of a variety of recent studies where this question has been addressed, comparing and contrasting the results and conclusions presented. We focus our attention on vibrated and vibrofluidized granular beds, which provide a canonical system representative of various equilibrium and nonequilibrium physical systems, and whose simple dynamics offer a valuable testing ground for exploring the fundamental physics of the granular state.
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.
Cummings, Anne R.; Carr, James E.; LeBlanc, Linda A.
2012-01-01
The Picture Exchange Communication System (PECS) is a picture-based alternative communication method that is widely accepted and utilized with individuals with disabilities. Although prior studies have examined the clinical efficacy of PECS, none have experimentally evaluated its manualized training structure. We experimentally evaluated the…
Lerna, Anna; Esposito, Dalila; Conson, Massimiliano; Russo, Luigi; Massagli, Angelo
2012-01-01
Background: The Picture Exchange Communication System (PECS) is a common treatment choice for non-verbal children with autism. However, little empirical evidence is available on the usefulness of PECS in treating social-communication impairments in autism. Aims: To test the effects of PECS on social-communicative skills in children with autism,…
Tincani, Matt; Devis, Kathryn
2011-01-01
The "Picture Exchange Communication System" (PECS) has emerged as the augmentative communication intervention of choice for individuals with autism spectrum disorder (ASD), with a supporting body of single-participant studies. This report describes a meta-analysis of 16 single-participant studies on PECS with percentage of nonoverlapping data…
Tincani, Matt
2004-01-01
This study compared the effects of Picture Exchange Communication System (PECS) and sign language training on the acquisition of mands (requests for preferred items) of students with autism. The study also examined the differential effects of each modality on students' acquisition of vocal behavior. Participants were two elementary school students…
A Review of the Efficacy of the Picture Exchange Communication System Intervention
Preston, Deborah; Carter, Mark
2009-01-01
The Picture Exchange Communication System (PECS) is a communication program that has become widely used, especially with children with autism. This paper reports the results of a review of the empirical literature on PECS. A descriptive review is provided of the 27 studies identified, which included randomized controlled trials (RCTs), other group…
The Picture Exchange Communication System (PECS): What Do the Data Say?
Sulzer-Azaroff, Beth; Hoffman, Anne O.; Horton, Catherine B.; Bondy, Andrew; Frost, Lori
2009-01-01
Originally designed to enable young children with autism lacking functional communication to initiate requests and to describe what they observed, the Picture Exchange Communication System (PECS) has been the subject of an ever-expanding body of research and development. Thirty-four peer-reviewed published reports on PECS are analyzed in this…
Marckel, Julie M.; Neef, Nancy A.; Ferreri, Summer J.
2006-01-01
Two young boys with autism who used the picture exchange communication system were taught to solve problems (improvise) by using descriptors (functions, colors, and shapes) to request desired items for which specific pictures were unavailable. The results of a multiple baseline across descriptors showed that training increased the number of…
Homlitas, Christa; Rosales, Rocío; Candel, Lindsay
2014-01-01
We evaluated the effectiveness of a behavioral skills training package to teach implementation of Phases 1, 2, and 3A of the picture exchange communication system (PECS) to teachers employed at a therapeutic center for children with autism. Probes in the natural environment and follow-up were conducted with children who were assigned to work with…
Understanding the Picture Exchange Communication System and Its Application in Physical Education
Green, Amanda; Sandt, Dawn
2013-01-01
This article presents the Picture Exchange Communication System (PECS) and its applications in physical education. The PECS is an appropriate communication intervention for students with autism who lack functional communication skills. It is often confused with other visual support strategies, so the authors delineate the six phases of PECS and…
Feru, E.; Willems, F.P.T.; Rojer, C.; Jager, B. de; Steinbuch, M.
2013-01-01
To meet future CO2 emission targets, Waste Heat Recovery systems have recently attracted much attention for automotive applications, especially for long haul trucks. This paper focuses on the development of a dynamic counter-flow heat exchanger model for control purposes. The model captures the
Using the Picture Exchange Communication System with Students with Visual Impairment
Ivy, Sarah E.; Hatton, Deborah D.; Hooper, Jonathan D.
2014-01-01
Students with visual impairment (VI) were taught to request using the Picture Exchange Communication System (PECS) and tangible symbols. Participants were four males with additional disabilities, 5 to 11 years old, who had little to no functional vision. A functional relation between PECS Phase 1 and requesting was established using a multiple…
Glavev, Victor
2016-12-01
The types of software applications used by public administrations can be divided in three main groups: document management systems, record management systems and business process systems. Each one of them generates outputs that can be used as input data to the others. This is the main reason that requires exchange of data between these three groups and well defined models that should be followed. There are also many other reasons that will be discussed in the paper. Interoperability is a key aspect when those models are implemented, especially when there are different manufactures of systems in the area of software applications used by public authorities. The report includes examples of implementation of models for exchange of data between software systems deployed in one of the biggest administration in Bulgaria.
Investigation of heat exchangers for energy conversion systems of megawatt-class space power plants
Ilmov, D. N.; Mamontov, Yu. N.; Skorohodov, A. S.; Smolyarov, V. A.; Filatov, N. I.
2016-01-01
The specifics of operation (high temperatures in excess of 1000 K and large pressure drops of several megapascals between "hot" and "cold" coolant paths) of heat exchangers in the closed circuit of a gasturbine power converter operating in accordance with the Brayton cycle with internal heat recovery are analyzed in the context of construction of space propulsion systems. The design of a heat-exchange matrix made from doubly convex stamped plates with a specific surface relief is proposed. This design offers the opportunity to construct heat exchangers with the required parameters (strength, rigidity, weight, and dimensions) for the given operating conditions. The diagram of the working area of a test bench is presented, and the experimental techniques are outlined. The results of experimental studies of heat exchange and flow regimes in the models of heat exchangers with matrices containing 50 and 300 plates for two pairs of coolants (gas-gas and gas-liquid) are detailed. A criterion equation for the Nusselt number in the range of Reynolds numbers from 200 to 20 000 is proposed. The coefficients of hydraulic resistance for each coolant path are determined as functions of the Reynolds number. It is noted that the pressure in the water path in the "gas-liquid" series of experiments remained almost constant. This suggests that no well-developed processes of vaporization occurred within this heat-exchange matrix design even when the temperature drop between gas and water was as large as tens or hundreds of degrees. The obtained results allow one to design flight heat exchangers for various space power plants.
Heat Exchanger Design Options and Tritium Transport Study for the VHTR System
Energy Technology Data Exchange (ETDEWEB)
Chang H. Oh; Eung S. Kim
2008-09-01
This report presents the results of a study conducted to consider heat exchanger options and tritium transport in a very high temperature reactor (VHTR) system for the Next Generation Nuclear Plant Project. The heat exchanger options include types, arrangements, channel patterns in printed circuit heat exchangers (PCHE), coolant flow direction, and pipe configuration in shell-and-tube designs. Study considerations include: three types of heat exchanger designs (PCHE, shell-and-tube, and helical coil); single- and two-stage unit arrangements; counter-current and cross flow configurations; and straight pipes and U-tube designs in shell-and-tube type heat exchangers. Thermal designs and simple stress analyses were performed to estimate the heat exchanger options, and the Finite Element Method was applied for more detailed calculations, especially for PCHE designs. Results of the options study show that the PCHE design has the smallest volume and heat transfer area, resulting in the least tritium permeation and greatest cost savings. It is theoretically the most reliable mechanically, leading to a longer lifetime. The two-stage heat exchanger arrangement appears to be safer and more cost effective. The recommended separation temperature between first and second stages in a serial configuration is 800oC, at which the high temperature unit is about one-half the size of the total heat exchanger core volume. Based on simplified stress analyses, the high temperature unit will need to be replaced two or three times during the plant’s lifetime. Stress analysis results recommend the off-set channel pattern configuration for the PCHE because stress reduction was estimated at up to 50% in this configuration, resulting in a longer lifetime. The tritium transport study resulted in the development of a tritium behavior analysis code using the MATLAB Simulink code. In parallel, the THYTAN code, previously performed by Ohashi and Sherman (2007) on the Peach Bottom data, was revived
Detection of stratosphere troposphere exchange in cut-off low systems
Price, Jeremy D.; Vaughan, Geraint
1994-01-01
The Aberystwyth MST radar has been used as part of the TOASTE program to study the structure of the tropopause in cut-off-low system with an aim to identifying regions where stratosphere-troposphere exchange are taking place. Theory predicts that the vertical gradient in reflected power is proportional to the static stability of the reflecting region, and should therefore resolve tropopause structure. Comparisons of MST power profiles with radiosonde data are presented and show good agreement, revealing regions of indefinite tropopauses, where stratosphere-troposphere exchange is thought to take place. The continuous nature of MST data allows an estimation of the size of these regions.
Directory of Open Access Journals (Sweden)
Li Dan
2014-06-01
Full Text Available The solubility of magnesium minerals and the refractive index of the ternary system MgBr2 + MgSO4 + H2O at 288.15 K were investigated using an isothermal dissolution method. It was found that there are two invariant points in the phase diagram and the solubility isotherm of this ternary system consists of three branches, corresponding to equilibrium crystallization of Epsomite (MgSO4·7H2O, Eps, hexahydrite (MgSO4·6H2O, Hex and magnesium bromide hexahydrate (MgBr2·6H2O, Mb. Neither solid solutions nor double salts were found. The refractive indices calculated from empirical equation are in good agreement with the experimental data. Combining the results from solubility measurements with the single-salt parameters for MgBr2 and MgSO4, and the mixed ion-interaction parameter θBr,S0(4, the parameter ψMg,Br,S0(4 at 288.15 K was fitted using the Pitzer theory and Harvie-Weare (HW approach. In addition, the average equilibrium constants of the stable equilibrium solids at 288.15 K were obtained by a method using the activity product constant. A chemical model, which combined the Pitzer parameters and the average equilibrium constants, was constructed to calculate the solid + liquid equilibria in the ternary system MgBr2 + MgSO4 + H2O at 288.15 K. The model agreed well with the equilibrium solubility data for the magnesium salts.
Activity systems modeling as a theoretical lens for social exchange studies
Directory of Open Access Journals (Sweden)
Ernest Jones
2016-01-01
Full Text Available The social exchange perspective seeks to acknowledge, understand and predict the dynamics of social interactions. Empirical research involving social exchange constructs have grown to be highly technical including confirmatory factor analysis to assess construct distinctiveness and structural equation modeling to assess construct causality. Each study seemingly strives to assess how underlying social exchange theoretic constructs interrelate. Yet despite this methodological depth and resultant explanatory and predictive power, a significant number of studies report findings that, once synthesized, suggest an underlying persistent threat of conceptual or construct validity brought about by a search for epistemological parsimony. Further, it is argued that a methodological approach that embraces inherent complexity such as activity systems modeling facilitates the search for simplified models while not ignoring contextual factors.
Serial robot for the trajectory optimization and error compensation of TMT mask exchange system
Wang, Jianping; Zhang, Feifan; Zhou, Zengxiang; Zhai, Chao
2015-10-01
Mask exchange system is the main part of Multi-Object Broadband Imaging Echellette (MOBIE) on the Thirty Meter Telescope (TMT). According to the conception of the TMT mask exchange system, the pre-design was introduced in the paper which was based on IRB 140 robot. The stiffness model of IRB 140 in SolidWorks was analyzed under different gravity vectors for further error compensation. In order to find the right location and path planning, the robot and the mask cassette model was imported into MOBIE model to perform different schemes simulation. And obtained the initial installation position and routing. Based on these initial parameters, IRB 140 robot was operated to simulate the path and estimate the mask exchange time. Meanwhile, MATLAB and ADAMS software were used to perform simulation analysis and optimize the route to acquire the kinematics parameters and compare with the experiment results. After simulation and experimental research mentioned in the paper, the theoretical reference was acquired which could high efficient improve the structure of the mask exchange system parameters optimization of the path and precision of the robot position.
Are there differences in health information exchange by health system type?
Opoku-Agyeman, William; Menachemi, Nir
2016-01-01
Despite the potential of health information exchange (HIE) to improve safety and reduce cost, hospitals have been slow to adopt HIE with only 30% of U.S. hospitals doing so in 2012. The aim of this study was to explore the relationship between different health system types and how they engage in HIE. Data on health system types and engagement in HIE activity were combined with secondary hospital characteristics. Ordinal logistic regression analyses were used to examine the relationship between a scale measuring the level of HIE engagement and health system type controlling for hospital and market characteristics. Data from 1552 hospitals were available for analyses. Overall, hospital in a health system of any kind exchanged more patient data elements (e.g., patient demographics, clinical summaries, laboratory results, medication history, and radiology report) compared with stand-alone hospitals (3.82 vs. 1.80, p difference in the exchange of patient health data. Hospital engagement in HIE is associated with health system membership. These findings will assist hospital leaders and managers to better understand how the structure and nature of their system may influence what their individual hospital can and cannot do in their decision to engage in HIE and other decisions that support the overall system objectives.
DEFF Research Database (Denmark)
Coutinho, João A.P.; Stenby, Erling Halfdan
1996-01-01
The predictive local composition model is applied to multicomponent hydrocarbon systems with long-chain n-alkanes as solutes. The results show that it can successfully be extended to highorder systems and accurately predict the solid appearance temperature, also known as cloud point, in solutions...... by considering the multiple orthorhombic phases as a single phase. It is shown that for low concentrations in heavy fraction the interaction parameter (alpha)_ls can be neglected and thus the model becomes purely predictive....
Effects of Picture Exchange Communication System on Communication and Behavioral Anomalies in Autism
Malhotra, Shahzadi; Rajender, Gaurav; Bhatia, Manjeet S.; Singh, Tej B.
2010-01-01
Communication skills deficits and stereotyped behaviors are frequently found among people with pervasive developmental disabilities like autism. These communication and behavioral oddities of autism are often considered to be difficult to treat and are challenging. Picture exchange communication system (PECS) is a six-phase picture system based on applied behavior analysis and is specially designed to overcome these communication difficulties in children with autism by encouraging the child t...
CRISCIONI FERREIRA, PATRICIA FABIOLA
2016-01-01
[EN] The main objective of this Thesis was to study the energy metabolism in small ruminants under different nutrition sceneries. As methodology we utilized indirect calorimetry instead of direct calorimetry or feeding trials. Within indirect calorimetry we worked with a portable open circuit gas exchange system with a head hood. This open circuit respiration system permitted completed the whole energy balance and evaluate the efficiency of utilization of the energy of the diet for different ...
Directory of Open Access Journals (Sweden)
Janković Milovan R.
2016-01-01
Full Text Available The liquid-liquid equilibrium constant for acetic acid in a quinary system olive oil-epoxidized olive oil-acetic acid-hydrogen peroxide-water was experimentally determined for temperatures and component ratios relevant for in situ epoxidation of plant oils. The values has the constant range from 1.52 to 2.73. To predict the equilibrium constant for acetic acid, the experimental data were correlated with UNIQUAC (universal quasi chemical and NRTL (non-random two liquid activity coefficient models. For simplified calculation of the phase equilibrium the insolubility of olive oil and epoxidized olive oil in the water, as well as insolubility of water and hydrogen peroxide in the olive oil and epoxidized olive oil, was assumed. The root mean square deviation (RMSD of the experimental and calculated values of the liquid-liquid equilibrium constant for acetic acid is 0.1910 for the UNIQUAC model and 0.1815 for the NRTL model. For rigorous flash calculation, when the partitioning of all components between the phases was assumed, the RMSD for the NRTL model is 0.1749. [Projekat Ministarstva nauke Republike Srbije, br. 45022
Energy Technology Data Exchange (ETDEWEB)
Davidson, J.H.
1998-06-01
The goals of this project are: (1) to develop guidelines for the design and use of thermosypohon side-arm heat exchangers in solar domestic water heating systems, and (2) to establish appropriate modeling and testing criteria for evaluating the performance of systems using this type of heat exchanger.
Heffler, Michael A.; Walters, Ryan D.; Kugel, Jennifer F.
2012-01-01
An undergraduate biochemistry laboratory experiment is described that will teach students the practical and theoretical considerations for measuring the equilibrium dissociation constant (K[subscript D]) for a protein/DNA interaction using electrophoretic mobility shift assays (EMSAs). An EMSA monitors the migration of DNA through a native gel;…
The strategic use of standardized information exchange technology in a university health system.
Cheng, Po-Hsun; Chen, Heng-Shuen; Lai, Feipei; Lai, Jin-Shin
2010-04-01
This article illustrates a Web-based health information system that is comprised of specific information exchange standards related to health information for healthcare services in National Taiwan University Health System. Through multidisciplinary teamwork, medical and informatics experts collaborated and studied on system scope definition, standard selection challenges, system implementation barriers, system management outcomes, and further expandability of other systems. After user requirement analysis and prototyping, from 2005 to 2008, an online clinical decision support system with multiple functions of reminding and information push was implemented. It was to replace its original legacy systems and serve among the main hospital and three branches of 180-200 clinics and 7,500-8,000 patient visits per day. To evaluate the effectiveness of this system, user surveys were performed, which revealed that the average score of user satisfaction increased from 2.80 to 3.18 on a 4-point scale. Among the items, especially e-learning for training service, courtesy communications for system requests, and courtesy communications for system operations showed statistically significant improvement. From this study, the authors concluded that standardized information exchange technologies can be used to create a brand new enterprise value and steadily obtain more competitive advantages for a prestige healthcare system.
Enabling Data Exchange in Two-Agent Interactive Systems Under Privacy Constraints
Belmega, E. Veronica; Sankar, Lalitha; Poor, H. Vincent
2015-10-01
Data collecting agents in large networks, such as the electric power system, need to share information (measurements) for estimating the system state in a distributed manner. However, privacy concerns may limit or prevent this exchange leading to a tradeoff between state estimation fidelity and privacy (referred to as competitive privacy). This paper builds upon a recent information-theoretic result (using mutual information to measure privacy and mean-squared error to measure fidelity) that quantifies the region of achievable distortion-leakage tuples in a two-agent network. The objective of this paper is to study centralized and decentralized mechanisms that can enable and sustain non-trivial data exchanges among the agents. A centralized mechanism determines the data sharing policies that optimize a network-wide objective function combining the fidelities and leakages at both agents. Using common-goal games and best-response analysis, the optimal policies allow for distributed implementation. In contrast, in the decentralized setting, repeated discounted games are shown to naturally enable data exchange without any central control nor economic incentives. The effect of repetition is modeled by a time-averaged payoff function at each agent which combines its fidelity and leakage at each interaction stage. For both approaches, it is shown that non-trivial data exchange can be sustained for specific fidelity ranges even when privacy is a limiting factor.
Pressure Pump Power Control in the Primary Circuit of the Heat Exchange System
Directory of Open Access Journals (Sweden)
Shilin Aleksandr
2017-01-01
Full Text Available In this paper we consider the problem of speed in hot water systems where highly efficient plate heat exchanger is used. Especially marked the problem which is connected with long transition drive of constant speed exceeding the time of the heat exchanger accumulative tank emptying more than twice. As a regulating element in the heat exchange system there was proposed to use asynchronous electric drive of pressure pump in the primary circuit of the heat exchanger. For correct use of such electric drive we solved the problem of control object mathematical model synthesis, which has non-linear properties, in particular, the transfer coefficient of the circuit can vary in more than 6 times. At the same time there was revealed the dependence of the transfer coefficient on the motor speed, which must be considered in the controller synthesis. In conclusion we suggested the solutions of regulators synthesis tasks with customizable settings for speed and switchable structure between relay λ and PI regulators.
Shevchenko, M.; Jak, E.
2017-12-01
The phase equilibria information on the Pb-Fe-O system is of practical importance for the improvement of the existing thermodynamic database of lead-containing slag systems (Pb-Zn-Fe-Cu-Si-Ca-Al-Mg-O). Phase equilibria of the Pb-Fe-O system have been investigated: (a) in air at temperatures between 1053 K and 1373 K (780 °C and 1100 °C); (b) in equilibrium with metallic lead at temperatures between 1053 K and 1373 K (780 °C and 1100 °C); and (c) at intermediate oxidation conditions for the liquid slag in equilibrium with two solids (spinel + magnetoplumbite), at temperatures between 1093 K and 1373 K (820 °C and 1100 °C). The high-temperature equilibration/quenching/electron probe X-ray microanalysis technique has been used to accurately determine the compositions of the phases in equilibrium in the system. The Pb and Fe concentrations in the phases were determined directly; preliminary thermodynamic modeling with FactSage was used to estimate the ferrous-to-ferric ratios and to present the results in the ternary diagram.
Loft, N. J. S.; Kristensen, L. B.; Thomsen, A. E.; Volosniev, A. G.; Zinner, N. T.
2016-12-01
We consider a one-dimensional system of particles with strong zero-range interactions. This system can be mapped onto a spin chain of the Heisenberg type with exchange coefficients that depend on the external trap. In this paper, we present an algorithm that can be used to compute these exchange coefficients. We introduce an open source code CONAN (Coefficients of One-dimensional N-Atom Networks) which is based on this algorithm. CONAN works with arbitrary external potentials and we have tested its reliability for system sizes up to around 35 particles. As illustrative examples, we consider a harmonic trap and a box trap with a superimposed asymmetric tilted potential. For these examples, the computation time typically scales with the number of particles as O(N 3.5 ± 0.4) . Computation times are around 10 s for N = 10 particles and less than 10 min for N = 20 particles.
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
Energy Technology Data Exchange (ETDEWEB)
Pereira, Milton A.P. [School of Chemical Engineering, State University of Campinas, P.O. Box 6066, 13081-970 Campinas-SP (Brazil); Aznar, Martin [School of Chemical Engineering, State University of Campinas, P.O. Box 6066, 13081-970 Campinas-SP (Brazil)]. E-mail: maznar@feq.unicamp.br
2006-06-15
(Liquid + liquid) equilibrium data for the quaternary systems (water + 2-propanol + 1-butanol + potassium bromide) and (water + 2-propanol + 1-butanol + magnesium chloride) were measured at T = 313.15 K and T = 353.15 K. The overall salt concentrations were 5 and 10 mass percent. Ternary (liquid + liquid) equilibrium data for the salt-free system (water + 2-propanol + 1-butanol) were also determined and found to be in good agreement with data from the literature. The NRTL model for the activity coefficient was used to correlate the data. New interaction parameters were estimated, using the Simplex minimization method and a concentration-based objective function. The results are very satisfactory, with root mean square deviations between experimental and calculated compositions of both phases being less than 0.5%.
Grating exchange system of independent mirror supported by floating rotary stage
Zhang, Jianhuan; Tao, Jin; Liu, Yan; Nan, Yan
2015-10-01
The performance of The Grating Exchange System can satisfy the Thirty Meter Telescope - TMT for astronomical observation WFOS index requirements and satisfy the requirement of accuracy in the grating exchange. It is used to install in the MOBIE and a key device of MOBIE. The Wide Field Optical Spectrograph (WFOS) is one of the three first-light observing capabilities selected by the TMT Science Advisory Committee. The Multi-Object Broadband Imaging Echellette (MOBIE) instrument design concept has been developed to address the WFOS requirements as described in the TMT Science-Based Requirements Document (SRD). The Grating Exchange System uses a new type of separate movement way of three grating devices and a mirror device. Three grating devices with a mirror are able to achieve independence movement. This kind of grating exchange system can effectively solve the problem that the volume of the grating change system is too large and that the installed space of MOBIE instruments is too limit. This system adopts the good stability, high precision of rotary stage - a kind of using air bearing (Air bearing is famous for its ultra-high precision, and can meet the optical accuracy requirement) and rotation positioning feedback gauge turntable to support grating device. And with a kind of device which can carry greater weight bracket fixed on the MOBIE instrument, with two sets of servo motor control rotary stage and the mirror device respectively. And we use the control program to realize the need of exercising of the grating device and the mirror device. Using the stress strain analysis software--SolidWorks for stress and strain analysis of this structure. And then checking the structure of the rationality and feasibility. And prove that this system can realize the positioning precision under different working conditions can meet the requirements of imaging optical grating diffraction efficiency and error by the calculation and optical performance analysis.
Energy Technology Data Exchange (ETDEWEB)
Yu, Byeonghun; Lee, Chang-Eon [Inha University, Incheon (Korea, Republic of); Kum, Sung Min [Halla University, Wonju (Korea, Republic of); Lee, Seungro [Chonbuk National University, Jeonju (Korea, Republic of)
2016-01-15
The effects of the number of heat exchanger modules on thermal characteristics were experimentally studied in a premixed combustion system with a cross-flow staggered-tube heat exchanger. The various heat exchanger modules, from 4 to 8, combined with a premixed burner were tested to investigate the performance of the heat exchanger through the surface area of the heat exchanger at various equivalence ratios. Additionally, the performance of the heat exchanger was analyzed by applying entropy generation theory to the heat exchanger system. As a result, although the heat transfer rate increases with the increase of the equivalence ratio, the NOx and CO concentrations also increase due to the increasing flame temperature. In addition, the entropy generation increases with an increase of the equivalence ratio. Furthermore, the heat transfer rate and the effectiveness are increased with the increase of the number of the heat exchanger modules. Also, the effectiveness is sharply increased when the number of the heat exchanger modules is increased from 4 to 5. Consequently, the optimal operating conditions regarding pollutant emission, effectiveness and entropy generation in this experimental range are 0.85 for the equivalence ratio and 8 for the number of heat exchanger modules.
Directory of Open Access Journals (Sweden)
Ren Yuan
2016-01-01
Full Text Available Current research status in energy management of Proton Exchange Membrane (PEM fuel cell hybrid power electric vehicles are first described in this paper, and then build the PEMFC/ lithium-ion battery/ ultra-capacitor hybrid system model. The paper analysis the key factors of the continuous power available in PEM fuel cell hybrid power electric vehicle and hybrid power system working status under different driving modes. In the end this paper gives the working flow chart of the hybrid power system and concludes the three items of the system performance analysis.
Real exchange rate misalignment and economic performance in ...
African Journals Online (AJOL)
This article investigates the behavior of equilibrium exchange rate and real exchange rate misalignment in Sudan over the period 1979– 2009. In addition, the impact of real exchange rate misalignment on economic performance is examined. The empirical results show that the equilibrium exchange rate is significantly ...
Heat transfer analysis of underground U-type heat exchanger of ground source heat pump system.
Pei, Guihong; Zhang, Liyin
2016-01-01
Ground source heat pumps is a building energy conservation technique. The underground buried pipe heat exchanging system of a ground source heat pump (GSHP) is the basis for the normal operation of an entire heat pump system. Computational-fluid-dynamics (CFD) numerical simulation software, ANSYS-FLUENT17.0 have been performed the calculations under the working conditions of a continuous and intermittent operation over 7 days on a GSHP with a single-well, single-U and double-U heat exchanger and the impact of single-U and double-U buried heat pipes on the surrounding rock-soil temperature field and the impact of intermittent operation and continuous operation on the outlet water temperature. The influence on the rock-soil temperature is approximately 13 % higher for the double-U heat exchanger than that of the single-U heat exchanger. The extracted energy of the intermittent operation is 36.44 kw·h higher than that of the continuous mode, although the running time is lower than that of continuous mode, over the course of 7 days. The thermal interference loss and quantity of heat exchanged for unit well depths at steady-state condition of 2.5 De, 3 De, 4 De, 4.5 De, 5 De, 5.5 De and 6 De of sidetube spacing are detailed in this work. The simulation results of seven working conditions are compared. It is recommended that the side-tube spacing of double-U underground pipes shall be greater than or equal to five times of outer diameter (borehole diameter: 180 mm).
Thermal stability of magnetic nanostructures in ion-bombardment-modified exchange-bias systems
Höink, V.; Sacher, M. D.; Schmalhorst, J.; Reiss, G.; Engel, D.; Weis, T.; Ehresmann, A.
2006-06-01
In magnetic bilayer systems consisting of a ferromagnet and an antiferromagnet the strength and direction of the exchange bias coupling can be set by ion bombardment in an external magnetic field. Magnetic nanostructures with a laterally varying exchange bias direction can be produced by local ion bombardment (ion bombardment induced magnetic patterning). We have investigated the thermal stability of these magnetic nanostructures by in situ x-ray photoemission electron microscopy while heating the samples above their blocking temperature. The investigations have been done at a 10.4μm×10.4μm large checkered pattern with a minimum size of the magnetic patterns of 800nm×800nm on a field cooled MnIr/CoFe stack and a pattern with 1.6μm wide lines with a periodicity of 5μm on an as-prepared MnIr/Co stack. The temperature dependence of the magnetization pattern can be explained by the temperature dependence of the exchange bias interaction, the exchange interaction energy, and the stray field energy. No substantial change of the thermal stability of magnetic patterns in remanence by the ion bombardment was found.
Building a national electronic medical record exchange system - experiences in Taiwan.
Li, Yu-Chuan Jack; Yen, Ju-Chuan; Chiu, Wen-Ta; Jian, Wen-Shan; Syed-Abdul, Shabbir; Hsu, Min-Huei
2015-08-01
There are currently 501 hospitals and about 20,000 clinics in Taiwan. The National Health Insurance (NHI) system, which is operated by the NHI Administration, uses a single-payer system and covers 99.9% of the nation's total population of 23,000,000. Taiwan's NHI provides people with a high degree of freedom in choosing their medical care options. However, there is the potential concern that the available medical resources will be overused. The number of doctor consultations per person per year is about 15. Duplication of laboratory tests and prescriptions are not rare either. Building an electronic medical record exchange system is a good method of solving these problems and of improving continuity in health care. In November 2009, Taiwan's Executive Yuan passed the 'Plan for accelerating the implementation of electronic medical record systems in medical institutions' (2010-2012; a 3-year plan). According to this plan, a patient can, at any hospital in Taiwan, by using his/her health insurance IC card and physician's medical professional IC card, upon signing a written agreement, retrieve all important medical records for the past 6 months from other participating hospitals. The focus of this plan is to establish the National Electronic Medical Record Exchange Centre (EEC). A hospital's information system will be connected to the EEC through an electronic medical record (EMR) gateway. The hospital will convert the medical records for the past 6 months in its EMR system into standardized files and save them on the EMR gateway. The most important functions of the EEC are to generate an index of all the XML files on the EMR gateways of all hospitals, and to provide search and retrieval services for hospitals and clinics. The EEC provides four standard inter-institution EMR retrieval services covering medical imaging reports, laboratory test reports, discharge summaries, and outpatient records. In this system, we adopted the Health Level 7 (HL7) Clinical Document
Energy Technology Data Exchange (ETDEWEB)
Hadlich de Oliveira, Leonardo [School of Chemical Engineering, State University of Campinas, UNICAMP, P.O. Box 6066, 13083-970 Campinas-SP (Brazil); Aznar, Martin, E-mail: maznar@feq.unicamp.b [School of Chemical Engineering, State University of Campinas, UNICAMP, P.O. Box 6066, 13083-970 Campinas-SP (Brazil)
2010-11-15
(Liquid + liquid) equilibrium (LLE) and binodal curve data were determined for the systems (water + phenol + tert-butanol) at T = 298.15 K, (water + phenol + 2-butanol) and (water + phenol + 1-butanol) at T = 298.15 K and T = 313.15 K by the combined techniques of densimetry and refractometry. Type I curve (for tert-butanol) and Type II curves (for 1- and 2-butanol) were found. The data were correlated with the NRTL model and the parameters estimated present root mean square deviations below 2% for the system with tert-butanol and lower than 0.8% for the other systems.
Energy Technology Data Exchange (ETDEWEB)
Yu, Samuel; Kim, Sun Min [Inha University, Incheon (Korea, Republic of)
2011-04-15
In this study, we developed a micromixer based on the non-equilibrium electrokinetics at the junction of a microchannel and nanochannel. Two fluid streams were mixed by an electro-osmotic flow and a vortex flow created as a result of the non-equilibrium electrokinetics at the junction of the microchannel and nanochannel. Initially, the microchannel was fabricated using Polydimethylsiloxane (PDMS) by the general soft lithography process and the nanochannel was created at a specific position on the microchannel by applying a high voltage. To evaluate the mixing performance of the micromixer, fluorescent distribution was analyzed by using the fluorescent dye, Rhodamine B. About 90% mixing was achieved with this novel micromixer, and this micromixer can be used in microsystems for biochemical sample analysis.
DEFF Research Database (Denmark)
Lang, Susann-Cathrin; Hursthouse, Andrew; Mayer, Philipp
2015-01-01
Solid Phase Microextraction (SPME) was applied to provide the first large scale dataset of freely dissolved concentrations for 9 polycyclic aromatic hydrocarbons (PAHs) in Baltic Sea sediment cores. Polydimethylsiloxane (PDMS) coated glass fibers were used for ex-situ equilibrium sampling followe...... to cause narcosis to benthos organisms. The SPME method is a very sensitive tool that opens new possibilities for studying the PAHs at trace levels in marine environments....
The Picture Exchange Communication System and his application of child with autism spectrum disorder
Kozlová, Veronika
2011-01-01
The bachelor thesis with title "The Picture Exchange Communication System and his application of child with autism spectrum disorder", deals with problems in communication of the children with autism spectrum disorders. One of the goals of the thesis is to submit a comprehensive overview of the essential knowledge of autism, history of autism, typical triad of symptoms (characteristic features of children with autism), etiology, and dividing autism by the adaptability. Another goal is to intr...
Marckel, Julie M; Neef, Nancy A; Ferreri, Summer J
2006-01-01
Two young boys with autism who used the picture exchange communication system were taught to solve problems (improvise) by using descriptors (functions, colors, and shapes) to request desired items for which specific pictures were unavailable. The results of a multiple baseline across descriptors showed that training increased the number of improvised requests, and that these skills generalized to novel items, and across settings and listeners in the natural environment.
Factors influencing intentions to use social recommender systems: a social exchange perspective.
Chang, Tsung-Sheng; Hsiao, Wei-Hung
2013-05-01
This study employs the perspective of social exchange theory and seeks to understand users' intentions to use social recommender systems (SRS) through three psychological factors: trust, shared values, and reputation. We use structural equation modeling to analyze 221 valid questionnaires. The results show that trust has a direct positive influence on the intention to use SRS, followed by shared values, whereas reputation has an indirect influence on SRS use. We further discuss specific recommendations concerning these factors for developing SRS.
A Generic Data Exchange System for Friend-to-Friend Networks
Soler, Cyril
2017-01-01
Decentralized private networks (a.k.a. darknets) guaranty privacy and concealment of information against global observers. Although a significant number of decentralized data distribution systems ex- ist, most of them target peer-to-peer architectures where any pair of nodes can exchange data using a temporary encrypted connection. Little has been done to achieve the same confidentiality in static darknet architectures, also known as “Friend-to-Friend” net- works, in which participants form a...
The Environmental Information Exchange Network (EIEN) is an Internet-based system used by state, tribal and territorial partners to securely share environmental and health information with one another and EPA.
Analysis and Perspective from the Complex Aerospace Systems Exchange (CASE) 2013
Jones, Kennie H.; Parker, Peter A.; Detweiler, Kurt N.; McGowan, Anna-Maria R.; Dress, David A.; Kimmel, William M.
2014-01-01
NASA Langley Research Center embedded four rapporteurs at the Complex Aerospace Systems Exchange (CASE) held in August 2013 with the objective to capture the essence of the conference presentations and discussions. CASE was established to provide a discussion forum among chief engineers, program managers, and systems engineers on challenges in the engineering of complex aerospace systems. The meeting consists of invited presentations and panels from industry, academia, and government followed by discussions among attendees. This report presents the major and reoccurring themes captured throughout the meeting and provides analysis and insights to further the CASE mission.
Energy Technology Data Exchange (ETDEWEB)
Gonzalez, Emilio J. [Departamento de Ingenieria Quimica de la Universidad de Vigo, 36310 Vigo (Spain); Laboratory of Separation and Reaction Engineering, LSRE, Departamento de Engenharia Quimica, Facultade de Engenharia, Universidade de Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Calvar, Noelia, E-mail: noecs@uvigo.e [Laboratory of Separation and Reaction Engineering, LSRE, Departamento de Engenharia Quimica, Facultade de Engenharia, Universidade de Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Dominguez, Irene; Dominguez, Angeles [Departamento de Ingenieria Quimica de la Universidad de Vigo, 36310 Vigo (Spain)
2011-05-15
Research highlights: [EMim][ESO{sub 4}] was studied as solvent to extract ethylbenzene from cycloalkanes. (Liquid + liquid) equilibrium data were measured at 298.15K and atmospheric pressure. Selectivity and solute distribution ratio were obtained and compared with literature. Experimental data were satisfactorily correlated using NRTL and UNIQUAC models. [EMim][ESO{sub 4}] can be used as solvent for the studied (liquid + liquid) extraction. - Abstract: In this paper, (liquid + liquid) equilibrium (LLE) data for the ternary systems (cyclohexane, or cyclooctane, or methylcyclohexane + ethylbenzene + 1-ethyl-3-methylimidazolium ethylsulfate) have been determined experimentally at T = 298.15 K and atmospheric pressure. The solubility curves and the tie-line compositions of the conjugate phases were obtained by means of density. The degree of consistency of the tie-lines was tested using the Othmer-Tobias equation, and the Non-Random Two-Liquid (NRTL) and the Universal Quasi-Chemical (UNIQUAC) models were used to correlate the phase equilibrium in the systems. Selectivity and solute distribution ratio were evaluated for the immiscible region.
Marinescu, Daniela-Crina; Pincu, Elena; Meltzer, Viorica
2013-05-20
Solid-liquid equilibrium (SLE) for binary mixture of Propafenone Hydrocloride (PP) with Metoprolol Tartrate (MT) was investigated using differential scanning calorimetry (DSC) and corresponding activity coefficients were calculated. Simple eutectic behavior for this system was observed. The excess thermodynamic functions: G(E) and S(E) for the pre-, post-, and eutectic composition have been obtained using the computed activity coefficients data of the eutectic phase with their excess chemical potentials μi(E) (i=1, 2). The experimental solid-liquid phase temperatures were compared with predictions obtained from available eutectic equilibrium models. The results indicate non-ideality in this mixture. Also, the compatibility of each component and their eutectic mixture with usual excipients was investigated, and the DSC experiments indicate possible weak interactions with α-lactose monohydrate and compatibility with corn starch. The results obtained were confirmed by FT-IR measurements. Copyright © 2013 Elsevier B.V. All rights reserved.
Tang, Tie-Qiao; Wang, Tao; Chen, Liang; Huang, Hai-Jun
2018-01-01
In this paper, we introduce the fuel cost into each commuter's trip cost, define a new trip cost without late arrival and its corresponding equilibrium state, and use a car-following model to explore the impacts of the fuel cost on each commuter's departure time, departure interval, arrival time, arrival interval, traveling time, early arrival time and trip cost at the above equilibrium state. The numerical results show that considering the fuel cost in each commuter's trip cost has positive impacts on his trip cost and fuel cost, and the traffic situation in the system without late arrival, i.e., each commuter should explicitly consider the fuel cost in his trip cost.
Development of a system using the library of the Genie spectroscopy software and exchange of samples
Energy Technology Data Exchange (ETDEWEB)
Lapolli, Andre L.; Munita, Casimiro S., E-mail: alapolli@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)
2011-07-01
One the great difficulties in using the NAA method is in regards to the time that the operator spends exchanging the samples after each measurement. It becomes a big problem in routine analyses when various chemical elements are determined and then each sample must be measured at different decay times. The application of the automatic sample exchanger reduces the time analysis by several hours and reduces the tedious manual operation. Then, the effective use of NAA depends on the availability of a suitable automatic sample changer. There are some systems that are sold commercially, however many laboratories can not acquire them because they are costly. This paper presents altered programs the G2KNAA.REX, which created a screen making possible automatic or manual acquisitions by calling the old program NAAACQ.rex for the procurement manual and the new program NAAACQ2.rex for automatic requisitions. In conclusion, as can be seen in the program lines, the synchronization to automation, which unites the three systems (the computer, the Canberra Set, the sample exchanger) is done in a timely manner. The system was tested and is functioning in a satisfactory manner. (author)
Norris, Zach; Mawson, Cara; Johnson, Kyron; Kessler, Sarah; Rebecca, Anne; Wolf, Nathan; Lim, Michael; Nucci, Nathaniel
Reverse micelles are molecular complexes that encapsulate a nanoscale pool of water in a surfactant shell dissolved in non-polar solvent. These complexes have a wide range of applications, and in all cases, the degree to which reverse micelles (RM) exchange their contents is relevant for their use. Despite its importance, this aspect of RM behavior is poorly understood. Photolithography is employed here to create micro and nano scale fluidic systems in which mixing rates can be precisely measured using fluorescence correlation spectroscopy (FCS). Micro-channel patterns are etched using reactive ion etching process into a layer of silicon dioxide on crystalline silicon substrates. Solutions containing mixtures of reverse micelles, proteins, and fluorophores are placed into reservoirs in the patterns, while diffusion and exchange between RMs is monitored using a FCS system built from a modified confocal Raman spectrometer. Using this approach, the diffusion and exchange rates for RM systems are measured as a function of the components of the RM mixture. Funding provided by Rowan University.
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
Energy Technology Data Exchange (ETDEWEB)
Mehl, Ana; Pessoa, Fernando L.P.; Silva, Silvia M.C. da [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica; Feiteira, Jose F. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Escola de Engenharia
2008-07-01
In separation process of multicomponent systems based on phase equilibrium is essential know the phase behavior and the critical points of the system for determination and optimization of the operational conditions. The experimental apparatus presents the challenge of determine the equilibrium phase dates of a system composed by petroleum residua and supercritical solvent. The used method, named acoustic method, allows the composition identification of the phases in equilibrium also in cloudy systems as they are the systems formed by residues of crude oil. For this reason, the acoustic methodology, based on the ultra-sound technology will be used in the study of the phase equilibrium and experimental characterization of the system, in benches scale, operating in severe conditions of temperature and pressure.The acoustic method is one not invasive and not subjective technique, what becomes the work in high pressures safer. (author)
Salvatore, Sergio; Tschacher, Wolfgang
2012-01-01
This paper provides a general framework for the use of Theory of Dynamic Systems (TDS) in the field of psychotherapy research. Psychotherapy is inherently dynamic, namely a function of time. Consequently, the improvement of construct validity and clinical relevance of psychotherapy process research require the development of models of investigation allowing dynamic mappings of clinical exchange. Thus, TDS becomes a significant theoretical and methodological reference. The paper focuses two topics. First, the main concepts of TDS are briefly introduced together with a basic typology of approaches developed within this domain. Second, we propose a repertoire of investigation strategies that can be used to capture the dynamic nature of clinical exchange. In this way we intend to highlight the feasibility and utility of strategies of analysis informed by TDS.
Directory of Open Access Journals (Sweden)
Sergio eSalvatore
2012-07-01
Full Text Available This paper provides a general framework for the use of TDS in the field of psychotherapy research. Psychotherapy is inherently dynamic, namely a function of time. Consequently, the improvement of construct validity and clinical relevance of psychotherapy process research require the development of models of investigation allowing dynamic mappings of clinical exchange. Thus, the Theory of Dynamic Systems (TDS becomes a significant theoretical and methodological reference. The paper focuses two topics. First, the main concepts of TDS are briefly introduced together with a basic typology of approaches developed within this domain. Second, we propose a repertoire of investigation strategies that can be used to capture the dynamic nature of clinical exchange. In this way we intend to highlight the feasibility and utility of strategies of analysis informed by TDS.
Ma, Jian; Lu, Chen; Liu, Hongmei
2015-01-01
The aircraft environmental control system (ECS) is a critical aircraft system, which provides the appropriate environmental conditions to ensure the safe transport of air passengers and equipment. The functionality and reliability of ECS have received increasing attention in recent years. The heat exchanger is a particularly significant component of the ECS, because its failure decreases the system's efficiency, which can lead to catastrophic consequences. Fault diagnosis of the heat exchanger is necessary to prevent risks. However, two problems hinder the implementation of the heat exchanger fault diagnosis in practice. First, the actual measured parameter of the heat exchanger cannot effectively reflect the fault occurrence, whereas the heat exchanger faults are usually depicted by utilizing the corresponding fault-related state parameters that cannot be measured directly. Second, both the traditional Extended Kalman Filter (EKF) and the EKF-based Double Model Filter have certain disadvantages, such as sensitivity to modeling errors and difficulties in selection of initialization values. To solve the aforementioned problems, this paper presents a fault-related parameter adaptive estimation method based on strong tracking filter (STF) and Modified Bayes classification algorithm for fault detection and failure mode classification of the heat exchanger, respectively. Heat exchanger fault simulation is conducted to generate fault data, through which the proposed methods are validated. The results demonstrate that the proposed methods are capable of providing accurate, stable, and rapid fault diagnosis of the heat exchanger.
Directory of Open Access Journals (Sweden)
Jian Ma
Full Text Available The aircraft environmental control system (ECS is a critical aircraft system, which provides the appropriate environmental conditions to ensure the safe transport of air passengers and equipment. The functionality and reliability of ECS have received increasing attention in recent years. The heat exchanger is a particularly significant component of the ECS, because its failure decreases the system's efficiency, which can lead to catastrophic consequences. Fault diagnosis of the heat exchanger is necessary to prevent risks. However, two problems hinder the implementation of the heat exchanger fault diagnosis in practice. First, the actual measured parameter of the heat exchanger cannot effectively reflect the fault occurrence, whereas the heat exchanger faults are usually depicted by utilizing the corresponding fault-related state parameters that cannot be measured directly. Second, both the traditional Extended Kalman Filter (EKF and the EKF-based Double Model Filter have certain disadvantages, such as sensitivity to modeling errors and difficulties in selection of initialization values. To solve the aforementioned problems, this paper presents a fault-related parameter adaptive estimation method based on strong tracking filter (STF and Modified Bayes classification algorithm for fault detection and failure mode classification of the heat exchanger, respectively. Heat exchanger fault simulation is conducted to generate fault data, through which the proposed methods are validated. The results demonstrate that the proposed methods are capable of providing accurate, stable, and rapid fault diagnosis of the heat exchanger.
Two-Phase Cryogenic Heat Exchanger for the Thermodynamic Vent System
Christie, Robert J.
2011-01-01
A two-phase cryogenic heat exchanger for a thermodynamic vent system was designed and analyzed, and the predicted performance was compared with test results. A method for determining the required size of the Joule-Thomson device was also developed. Numerous sensitivity studies were performed to show that the design was robust and possessed a comfortable capacity margin. The comparison with the test results showed very similar heat extraction performance for similar inlet conditions. It was also shown that estimates for Joule- Thomson device flow rates and exit quality can vary significantly and these need to be accommodated for with a robust system design.
International Prices and Exchange Rates
Gopinath, Gita; Burstein, Ariel
2013-01-01
We survey the recent empirical and theoretical developments in the literature on the relation between prices and exchange rates. After updating some of the major findings in the empirical literature we present a simple framework to interpret this evidence. We review theoretical models that generate insensitivity of prices to exchange rate changes through variable markups, both under flexible prices and nominal rigidities, first in partial equilibrium and then in general equilibrium.
Directory of Open Access Journals (Sweden)
Isaac Skavdahl
2016-12-01
Full Text Available Alternative control schemes for an Advanced High Temperature Reactor system consisting of a reactor, an intermediate heat exchanger, and a secondary heat exchanger (SHX are presented in this paper. One scheme is designed to control the cold outlet temperature of the SHX (Tco and the hot outlet temperature of the intermediate heat exchanger (Tho2 by manipulating the hot-side flow rates of the heat exchangers (Fh/Fh2 responding to the flow rate and temperature disturbances. The flow rate disturbances typically require a larger manipulation of the flow rates than temperature disturbances. An alternate strategy examines the control of the cold outlet temperature of the SHX (Tco only, since this temperature provides the driving force for energy production in the power conversion unit or the process application. The control can be achieved by three options: (1 flow rate manipulation; (2 reactor power manipulation; or (3 a combination of the two. The first option has a quicker response but requires a large flow rate change. The second option is the slowest but does not involve any change in the flow rates of streams. The third option appears preferable as it has an intermediate response time and requires only a minimal flow rate change.
Improvement of an automated protein crystal exchange system PAM for high-throughput data collection
Energy Technology Data Exchange (ETDEWEB)
Hiraki, Masahiko, E-mail: masahiko.hiraki@kek.jp; Yamada, Yusuke; Chavas, Leonard M. G. [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Wakatsuki, Soichi [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); SLAC National Accelerator Laboratory, 2575 Sand Hill Road, MS 69, Menlo Park, CA 94025-7015 (United States); Stanford University, Beckman Center B105, Stanford, CA 94305-5126 (United States); Matsugaki, Naohiro [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan)
2013-11-01
A special liquid-nitrogen Dewar with double capacity for the sample-exchange robot has been created at AR-NE3A at the Photon Factory, allowing continuous fully automated data collection. In this work, this new system is described and the stability of its calibration is discussed. Photon Factory Automated Mounting system (PAM) protein crystal exchange systems are available at the following Photon Factory macromolecular beamlines: BL-1A, BL-5A, BL-17A, AR-NW12A and AR-NE3A. The beamline AR-NE3A has been constructed for high-throughput macromolecular crystallography and is dedicated to structure-based drug design. The PAM liquid-nitrogen Dewar can store a maximum of three SSRL cassettes. Therefore, users have to interrupt their experiments and replace the cassettes when using four or more of them during their beam time. As a result of investigation, four or more cassettes were used in AR-NE3A alone. For continuous automated data collection, the size of the liquid-nitrogen Dewar for the AR-NE3A PAM was increased, doubling the capacity. In order to check the calibration with the new Dewar and the cassette stand, calibration experiments were repeatedly performed. Compared with the current system, the parameters of the novel system are shown to be stable.
Development of two-grating spectrometer for the charge exchange spectroscopy system on KSTAR
Lee, Hyungho; Song, Eun-ji; Park, Young-dong; Oh, Soo-ghee; Ko, Won-Ha
2011-06-01
The charge exchange spectroscopy (CES) system on Korea Superconducting Tokamak Advanced Research (KSTAR) was installed last year and had been applied to measure the C VI ion temperature and rotation velocity profiles. The ion temperature and rotation velocity profiles had been estimated from the C VI 5290.5 Å (n = 8-7) charge-exchange spectrum signal measured by a Czerny-Turner type spectrometer and a thinned back-illuminated charge coupled device (CCD) camera. However, the Czerny-Turner type spectrometer used for the KSTAR CES system showed so low signal to noise ratio for KSTAR plasmas in the 2010 experimental campaign that the time resolution of the CES system had been limited to 100 ms due to the increased exposure time of the attached CCD camera. Then, new two-grating spectrometer had been developed in order to improve the time resolution of the CES system. The spectrometer consists of two gratings (1200 g/mm and 1800 g/mm each) with additive configuration, concave mirrors (f = 50 cm), and a cylindrical lens (f = 50 cm). The time resolution of the CES system increases by a factor of 2-4 with the two-grating spectrometer. The C VI ion temperature and rotation velocity profiles obtained by the two-grating spectrometer are compared to those by Czerny-Turner type spectrometer in this paper.
Rapid RNA Exchange in Aqueous Two-Phase System and Coacervate Droplets
Jia, Tony Z.; Hentrich, Christian; Szostak, Jack W.
2014-02-01
Compartmentalization in a prebiotic setting is an important aspect of early cell formation and is crucial for the development of an artificial protocell system that effectively couples genotype and phenotype. Aqueous two-phase systems (ATPSs) and complex coacervates are phase separation phenomena that lead to the selective partitioning of biomolecules and have recently been proposed as membrane-free protocell models. We show in this study through fluorescence recovery after photobleaching (FRAP) microscopy that despite the ability of such systems to effectively concentrate RNA, there is a high rate of RNA exchange between phases in dextran/polyethylene glycol ATPS and ATP/poly-L-lysine coacervate droplets. In contrast to fatty acid vesicles, these systems would not allow effective segregation and consequent evolution of RNA, thus rendering these systems ineffective as model protocells.
Study of heat exchange in cooling systems of heat-stressed structures
Vikulin, A. V.; Yaroslavtsev, N. L.; Zemlyanaya, V. A.
2017-01-01
Increasing working parameters of the cycle of gas-turbine engines, complicating design of gas-turbine plants, as well as growing aerodynamic, thermal, static, and dynamic loads, necessitate the development of promising cooling systems for heat-stressed structures. This work is devoted to an experimental study of heat exchange in ducts equipped with systems of inclined and cross walls (fins). It has been found that an increase in the Reynolds number Re from 3000 to 20000 leads to a decrease in the heat exchange, which is characterized by the relative Nusselt number overline{Nu}, by 19-30% at the angle of inclination of the walls φ = 0, 40°, 50°, and 90° if the length of the walls x w is comparable to the spacing b s and by 12-15% at φ = 30° and 90° if x w ≫ b s. If cross walls are used in cooling ducts, the length of the walls x w plays the governing role; an increase in this characteristic from 1.22 × 10-3 to 3.14 × 10-3 m leads to an increase in the intensity of heat exchange by 30-40% and to a decrease in the capacity of the entire system of the walls. It has been shown that, on surfaces with wavy fins, the intensity of heat exchange is closest to that determined in the models under study. For example, values of the Colborne criterion StPr2/3 for ducts equipped with wavy fins and for the models under study differ only slightly (by 2-20% depending on the value of the angle φ). However, the difference for surfaces with short plate fins and ducts equipped with inclined walls is high (30-40%). This is due to the design features of these surfaces and to the severe effect of the inlet portion on heat exchange, since the surfaces are characterized by a higher ratio of the duct length to the hydraulic diameter L/d h at small fin thicknesses ((0.1-0.15) × 10-3 m). The experimental results can be used in developing designs of nozzle and rotor blades of high-temperature gas turbines in gas-turbine engines and plants.
Matysik, Piotr; Jóźwiak, Stanisław; Czujko, Tomasz
2015-03-04
Fe-Al intermetallic alloys with aluminum content over 60 at% are in the area of the phase equilibrium diagram that is considerably less investigated in comparison to the high-symmetry Fe₃Al and FeAl phases. Ambiguous crystallographic information and incoherent data referring to the phase equilibrium diagrams placed in a high-aluminum range have caused confusions and misinformation. Nowadays unequivocal material properties description of FeAl₂, Fe₂Al₅ and FeAl₃ intermetallic alloys is still incomplete. In this paper, the influence of aluminum content and processing parameters on phase composition is presented. The occurrence of low-symmetry FeAl₂, Fe₂Al₅ and FeAl₃ structures determined by chemical composition and phase transformations was defined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) examinations. These results served to verify diffraction investigations (XRD) and to explain the mechanical properties of cast materials such as: hardness, Young's modulus and fracture toughness evaluated using the nano-indentation technique.
Ma, Jian; Lu, Chen; Liu, Hongmei
2015-01-01
The aircraft environmental control system (ECS) is a critical aircraft system, which provides the appropriate environmental conditions to ensure the safe transport of air passengers and equipment. The functionality and reliability of ECS have received increasing attention in recent years. The heat exchanger is a particularly significant component of the ECS, because its failure decreases the system’s efficiency, which can lead to catastrophic consequences. Fault diagnosis of the heat exchanger is necessary to prevent risks. However, two problems hinder the implementation of the heat exchanger fault diagnosis in practice. First, the actual measured parameter of the heat exchanger cannot effectively reflect the fault occurrence, whereas the heat exchanger faults are usually depicted by utilizing the corresponding fault-related state parameters that cannot be measured directly. Second, both the traditional Extended Kalman Filter (EKF) and the EKF-based Double Model Filter have certain disadvantages, such as sensitivity to modeling errors and difficulties in selection of initialization values. To solve the aforementioned problems, this paper presents a fault-related parameter adaptive estimation method based on strong tracking filter (STF) and Modified Bayes classification algorithm for fault detection and failure mode classification of the heat exchanger, respectively. Heat exchanger fault simulation is conducted to generate fault data, through which the proposed methods are validated. The results demonstrate that the proposed methods are capable of providing accurate, stable, and rapid fault diagnosis of the heat exchanger. PMID:25823010
Energy Technology Data Exchange (ETDEWEB)
De Cort, M.; Vries, G. de; Galmarini, S. [European Comission, Ispra (Italy). Inst. for Environment and Sustainability
2003-07-01
Shortly after the Chernobyl accident the European Commission initiated various activities with the scope to make early notification and reliable radiological information available to the EU member states in case of nuclear accidents. JRC-IES/REM in Ispra, Italy, is responsible for the scientific and technical development of three closely related projects that should be a source of valuable information to support decision support in European during major radiological accidents: ECURIE (European Community Urgent Radiological Information Exchange) notifies the competent authorities and continuously informs them about the current status of the accident and its consequences; EURDEP (European Radiological Data Exchange Platform) makes radiological monitoring data from most European countries available in real-time. Currently 23 European countries exchange on a daily basis gamma dose-rates; ENSEMBLE produces a comprehensive overview and comparison of the contamination predictions calculated by world-leading long-range dispersion models. Starting from the legal background these information systems are further described in detail, with an emphasis on their current status, our experience and the planned future developments. (orig.)
National Aeronautics and Space Administration — Develop an alkaline exchange membrane (AEM)for use as a polymer electrolyte in both fuel cell and electrolyzer systems. The ultimate goal in AEM development is...
Active heat exchange system development for latent heat thermal energy storage
Energy Technology Data Exchange (ETDEWEB)
Alario, J.; Kosson, R.; Haslett, R.
1980-01-01
The selection and evaluation phase of a program to develop active heat exchange concepts for latent heat thermal energy storage systems applicable to the utility industry is described. An evaluation of suitable storage media with melting points in the temperature range of interest (250 to 400/sup 0/C) limited the candidates to molten salts from the chloride, hydroxide and nitrate families, based on high storage capacity, good corrosion characteristics and availability in large quantities at reasonable cost. The specific salt recommended for laboratory tests was a chloride eutectic (20.5KCl-24.5NaCl-55.0MgCl/sub 2/% by wt), with a nominal melting point of 385/sup 0/C. Various active heat exchange concepts were identified from among three generic categories: scrapers, agitators/vibrators and slurries. The more practical ones were given a more detailed technical evaluation and an economic comparison with a passive tube-shell design for a reference application (300 MW/sub t/ storage for 6 hours). Two concepts were selected for hardware development: a direct contact heat exchanger in which molten salt droplets are injected into a cooler counterflowing stream of liquid metal carrier fluid, and a rotating drum scraper in which molten salt is sprayed onto the circumference of a rotating drum, which contains the fluid heat sink in an internal annulus near the surface. A fixed scraper blade removes the solidified salt from the surface which has been nickel plated to decrease adhesion forces. In addition to improving performance by providing a nearly constant heat transfer rate during discharge, these active heat exchanger concepts were estimated to cost at least 25% less than the passive tube-shell design.
Zhu, Weibin; Park, Jong M.; White, Michael J.; Nellis, Gregory F.; Gianchandani, Yogesh B.
2011-01-01
This article reports the evaluation of a Joule–Thomson (JT) cooling system that combines two custom micromachined components—a Si/glass-stack recuperative heat exchanger and a piezoelectrically actuated expansion microvalve. With the microvalve controlling the flow rate, this system can modulate cooling to accommodate varying refrigeration loads. The perforated plate Si/glass heat exchanger is fabricated with a stack of alternating silicon plates and Pyrex glass spacers. The microvalve utiliz...
A Novel RFID Sensing System Using Enhanced Surface Wave Technology for Battery Exchange Stations
Directory of Open Access Journals (Sweden)
Yeong-Lin Lai
2014-01-01
Full Text Available This paper presents a novel radio-frequency identification (RFID sensing system using enhanced surface wave technology for battery exchange stations (BESs of electric motorcycles. Ultrahigh-frequency (UHF RFID technology is utilized to automatically track and manage battery and user information without manual operation. The system includes readers, enhanced surface wave leaky cable antennas (ESWLCAs, coupling cable lines (CCLs, and small radiation patches (SRPs. The RFID sensing system overcomes the electromagnetic interference in the metallic environment of a BES cabinet. The developed RFID sensing system can effectively increase the efficiency of BES operation and promote the development of electric vehicles which solve the problem of air pollution as well as protect the environment of the Earth.
Directory of Open Access Journals (Sweden)
Liu Min
2010-01-01
Full Text Available In this paper, we introduce a hybrid iterative scheme for finding a common element of the set of solutions for a system of mixed equilibrium problems, the set of common fixed points for a nonexpansive semigroup and the set of solutions of the quasi-variational inclusion problem with multi-valued maximal monotone mappings and inverse-strongly monotone mappings in a Hilbert space. Under suitable conditions, some strong convergence theorems are proved. Our results extend some recent results in the literature.
DEFF Research Database (Denmark)
Liang, Xiaodong; Yan, Wei; Thomsen, Kaj
2015-01-01
parameters for the characterized non-associating pseudo-components of petroleum fluids. New pure component parameters of mono-ethylene glycol (MEG) are obtained by considering the liquid liquid equilibrium (LLE) data of MEG with normal hydrocarbons in the estimation process and a simple binary interaction......A critical test for the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (FOS) is the modeling of systems containing petroleum fluid and polar compounds. In this work, two approaches are proposed for the simplified PC-SAFT EOS to obtain the necessary pure component...
Smirnyagina, N. N.; Khaltanova, V. M.; Dasheev, D. E.; Lapina, A. E.
2017-05-01
Composite layers on the basis of carbides and borides the titan and silicon on titanic alloy VТ-1 are generated at diffused saturation by electron beam treatment in vacuum. Formation in a composite of MAX phase Ti3SiC2 is shown. Thermodynamic research of phase equilibrium in systems Ti-Si-C and Ti-B-C in the conditions of high vacuum is executed. The thermodynamics, formation mechanisms of superfirm layers borides and carbides of the titan and silicon are investigated.
Wenchao Yang; Shuhong Li; Xianliang Li; Yuanyuan Liang; Xiaosong Zhang
2015-01-01
Cryogenic CO2 capture is considered as a promising CO2 capture method due to its energy saving and environmental friendliness. The phase equilibrium analysis of CO2-mixtures at low temperature is crucial for the design and operation of a cryogenic system because it plays an important role in analysis of recovery and purity of the captured CO2. After removal of water and toxic gas, the main components in typical boiler gases are N2/CO2. Therefore, this paper evaluates the reliabilities of diff...
Ji, Hyerim; Yoo, Sooyoung; Heo, Eun-Young; Hwang, Hee; Kim, Jeong-Whun
2017-10-01
This study aimed to identify problems and issues that arise with the implementation of online health information exchange (HIE) systems in a medical environment and to identify solutions to facilitate the successful operation of future HIE systems in primary care clinics and hospitals. In this study, the issues that arose during the establishment and operation of an HIE system in a hospital were identified so that they could be addressed to enable the successful establishment and operation of a standard-based HIE system. After the issues were identified, they were reviewed and categorized by a group of experts that included medical information system experts, doctors, medical information standard experts, and HIE researchers. Then, solutions for the identified problems were derived based on the system development, operation, and improvement carried out during this work. Twenty-one issues were identified during the implementation and operation of an online HIE system. These issues were then divided into four categories: system architecture and standards, documents and data items, consent of HIE, and usability. We offer technical and policy recommendations for various stakeholders based on the experiences of operating and improving the online HIE system in the medical field. The issues and solutions identified in this study regarding the implementation and operate of an online HIE system can provide valuable insight for planners to enable them to successfully design and operate such systems at a national level in the future. In addition, policy support from governments is needed.
Observability and Estimation of Distributed Space Systems via Local Information-Exchange Networks
Fathpour, Nanaz; Hadaegh, Fred Y.; Mesbahi, Mehran; Rahmani, Amirreza
2011-01-01
Spacecraft formation flying involves the coordination of states among multiple spacecraft through relative sensing, inter-spacecraft communication, and control. Most existing formation-flying estimation algorithms can only be supported via highly centralized, all-to-all, static relative sensing. New algorithms are proposed that are scalable, modular, and robust to variations in the topology and link characteristics of the formation exchange network. These distributed algorithms rely on a local information exchange network, relaxing the assumptions on existing algorithms. Distributed space systems rely on a signal transmission network among multiple spacecraft for their operation. Control and coordination among multiple spacecraft in a formation is facilitated via a network of relative sensing and interspacecraft communications. Guidance, navigation, and control rely on the sensing network. This network becomes more complex the more spacecraft are added, or as mission requirements become more complex. The observability of a formation state was observed by a set of local observations from a particular node in the formation. Formation observability can be parameterized in terms of the matrices appearing in the formation dynamics and observation matrices. An agreement protocol was used as a mechanism for observing formation states from local measurements. An agreement protocol is essentially an unforced dynamic system whose trajectory is governed by the interconnection geometry and initial condition of each node, with a goal of reaching a common value of interest. The observability of the interconnected system depends on the geometry of the network, as well as the position of the observer relative to the topology. For the first time, critical GN&C (guidance, navigation, and control estimation) subsystems are synthesized by bringing the contribution of the spacecraft information-exchange network to the forefront of algorithmic analysis and design. The result is a
Ganz, Jennifer B.; Simpson, Richard L.
2004-01-01
Few studies on augmentative and alternative communication (AAC) systems have addressed the potential for such systems to impact word utterances in children with autism spectrum disorders (ASD). The Picture Exchange Communication System (PECS) is an AAC system designed specifically to minimize difficulties with communication skills experienced by…
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.
Pająk, Marek; Woźniczka, Magdalena; Vogt, Andrzej; Kufelnicki, Aleksander
2017-09-19
The paper examines Co(II)-amino acid-imidazole systems (where amino acid = L-α-amino acid: alanine, asparagine, histidine) which, when in aqueous solutions, activate and reversibly take up dioxygen, while maintaining the structural scheme of the heme group (imidazole as axial ligand and O2 uptake at the sixth, trans position) thus imitating natural respiratory pigments such as myoglobin and hemoglobin. The oxygenated reaction shows higher reversibility than for Co(II)-amac systems with analogous amino acids without imidazole. Unlike previous investigations of the heteroligand Co(II)-amino acid-imidazole systems, the present study accurately calculates all equilibrium forms present in solution and determines the [Formula: see text]equilibrium constants without using any simplified approximations. The equilibrium concentrations of Co(II), amino acid, imidazole and the formed complex species were calculated using constant data obtained for analogous systems under oxygen-free conditions. Pehametric and volumetric (oxygenation) studies allowed the stoichiometry of O2 uptake reaction and coordination mode of the central ion in the forming oxygen adduct to be determined. The values of dioxygen uptake equilibrium constants [Formula: see text] were evaluated by applying the full mass balance equations. Investigations of oxygenation of the Co(II)-amino acid-imidazole systems indicated that dioxygen uptake proceeds along with a rise in pH to 9-10. The percentage of reversibility noted after acidification of the solution to the initial pH ranged within ca 30-60% for alanine, 40-70% for asparagine and 50-90% for histidine, with a rising tendency along with the increasing share of amino acid in the Co(II): amino acid: imidazole ratio. Calculations of the share of the free Co(II) ion as well as of the particular complex species existing in solution beside the oxygen adduct (regarding dioxygen bound both reversibly and irreversibly) indicated quite significant values for the
A gas-exchange system for assessing plant performance in response to environmental stress
Energy Technology Data Exchange (ETDEWEB)
Taylor, G.E. Jr; Tingey, D.T.
1979-10-01
Anthropogenic stresses are increasingly common as environmental factors affecting the performance of plants in both natural and agro-ecosystems. There is a need to determine how these stresses may influence vital physiological processes in plants. This report documents the design, construction and performance of a whole-plant, gas-exchange system that can accurately monitor gas flux (e.g., carbon dioxide, water vapor, pollutants) between plants and the atmospheric environment. From these data, rates of key physiological processes--photosynthesis, transpiration, gaseous uptake and emission--can be assessed. Example studies are reported on the uptake of sulfur dioxide by plants and emissions of monoterpenes from plants.
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.
Energy Technology Data Exchange (ETDEWEB)
Fristak, Vladimir; Soja, Gerhard [Austrian Institute of Technology GmbH, Tulln (Austria). Energy Dept. Environmental Resources and Technologies; Michalekova-Richveisova, Barbora; Pipiska, Martin [Trnava Univ. (Slovakia). Dept. of Chemistry; Viglasova, Eva; Galambos, Michal [Comenius Univ., Bratislava (Slovakia). Dept. of Inorganic Chemistry; Duriska, Libor [Slovak Univ. of Technology in Bratislava, Trnava (Slovakia). Faculty of Materials Science and Technology; Moreno-Jimenez, Eduardo [Univ. Autonoma de Madrid (Spain). Dept. de Quimica Agricola y Bromatologia
2017-03-15
The utilization of carbonaceous materials in separation processes of radionuclides, heavy metals and metalloids represents a burning issue in environmental and waste management. The main objective of this study was to characterize the effect of chemical modification of corncob-derived biochar by Fe-impregnations on sorption efficiency of Eu and As as a model compounds of cationic lanthanides and anionic metalloids. The biochar sample produced in slow pyrolysis process at 500 C before (BC) and after (IBC) impregnation process was characterized by elemental, FTIR, SEM-EDX analysis to confirm the effectiveness of Fe-impregnation process. The basic physico-chemical properties showed differences in surface area and pH values of BC- and IBC-derived sorbents. Sorption processes of Eu and As by BC and IBC were characterized as a time- and initial concentration of sorbate-dependent processes. The sorption equilibrium was reached for both sorbates in 24 h of contact time. Batch equilibrium experiments revealed the increased maximum sorption capacities (Q{sub max}) of IBC for As about more than 20 times (Q{sub max} BC 0.11 and Q{sub max} IBC 2.26 mg g{sup -1}). Our study confirmed negligible effect of Fe-impregnation on sorption capacity of biochar for Eu (Q{sub max} BC 0.89 and Q{sub max} IBC 0.98 mg g{sup -1}). The iron-impregnation of biochar-derived sorbents can be utilized as a valuable treatment method to produce stable and more effective sorption materials for various xenobiotics separation from liquid wastes and aqueous solutions.
Directory of Open Access Journals (Sweden)
Minghui CUI
2016-10-01
Full Text Available Plate heat exchanger has unique advantages and becomes dominant heat exchange equipment in heating engineering, but there is no heating regulation formula of plate exchanger applied in central heating regulation of indirect connection hot water heating. This paper analyzes the condition that the heating user's system adopts quality regulation method and the hot water network system adopts quality-flow regulation method, and obtains the regulation formulas of plate exchanger applied in central heating regulation of indirect connection hot water heating used for the above two systems. Empirical calculation shows that the formula can be applied to the quality regulation and the mass flow regulation of the different flow optimization adjustment coefficient, and it is an all-round formula.
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
Kinetic model of mass exchange with dynamic Arrhenius transition rates
Hristopulos, Dionissios T.; Muradova, Aliki
2016-02-01
We study a nonlinear kinetic model of mass exchange between interacting grains. The transition rates follow the Arrhenius equation with an activation energy that depends dynamically on the grain mass. We show that the activation parameter can be absorbed in the initial conditions for the grain masses, and that the total mass is conserved. We obtain numerical solutions of the coupled, nonlinear, ordinary differential equations of mass exchange for the two-grain system, and we compare them with approximate theoretical solutions in specific neighborhoods of the phase space. Using phase plane methods, we determine that the system exhibits regimes of diffusive and growth-decay (reverse diffusion) kinetics. The equilibrium states are determined by the mass equipartition and separation nullcline curves. If the transfer rates are perturbed by white noise, numerical simulations show that the system maintains the diffusive and growth-decay regimes; however, the noise can reverse the sign of equilibrium mass difference. Finally, we present theoretical analysis and numerical simulations of a system with many interacting grains. Diffusive and growth-decay regimes are established as well, but the approach to equilibrium is considerably slower. Potential applications of the mass exchange model involve coarse-graining during sintering and wealth exchange in econophysics.
Lack of Agreement Between Gas Exchange Variables Measured by Two Metabolic Systems
Jakovljevic, Djordje G.; Nunan, David; Donovan, Gay; Hodges, Lynette D.; Sandercock, Gavin R. H.; Brodie, David A.
2008-01-01
The purpose of this study was to assess the agreement and consistency between gas exchange variables measured by two online metabolic systems during an incremental exercise test. After obtaining local ethics approval and informed consent, 15 healthy subjects performed an incremental exercise test to volitional fatigue using the Bruce protocol. The Innocor (Innovision, Denmark) and CardiO2 (Medical Graphics, USA) systems were placed in series, with the Innocor mouthpiece attached to the pneumotach of the CardiO2. Metabolic data were analysed during the last 30 seconds of each stage and at peak exercise. There were non- significant differences (p > 0.05) between the two systems in estimation of oxygen consumption (VO2) and in minute ventilation (VE). Mean Cronbach’s alpha for VO2 and VE were 0.88 and 0.92. The Bland-Altman analysis revealed that limits of agreement were -0.52 to 0.55 l.min-1 for VO2, and -8.74 to 10.66 l.min-1 for VE. Carbon dioxide production (VCO2) and consequently respiratory exchange ratio (RER) measured by the Innocor were significantly lower (p < 0.05) through all stages. The CardiO2 measured fraction of expired carbon dioxide (FeCO2) significantly higher (p < 0.05). The limits of agreement for VO2 and VE are wide and unacceptable in cardio-pulmonary exercise testing. The Innocor reported VCO2 systematically lower. Therefore the Innocor and CardiO2 metabolic systems cannot be used interchangeably without affecting the diagnosis of an individual patient. Results from the present study support previous suggestion that considerable care is needed when comparing metabolic data obtained from different automated metabolic systems. Key pointsThere is general concern regarding the limited knowledge available about the accuracy of a number of commercially available systems.Demonstrated limits of agreement between key gas exchange variables (oxygen consumption and minute ventilation) as measured by the two metabolic systems were wide and unacceptable
Searching for an Appropriate Exchange Rate Regime
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Yunjong Wang
2001-06-01
Full Text Available This paper attempts to survey current debates on the choice of exchange rate regime in emerging market economies. The issue of choosing an appropriate exchange rate regime is being actively discussed since the recent Asian crisis. As a lesson from the recent crises, one widely shared conclusion is that soft peg exchange rate regimes are extremely vulnerable in a world of volatile capital movements. Consequently, new orthodoxy based on the impossible trinity hypothesis favours two corner solutions ― greater flexibility or credible institutional assurance, like a currency board system or dollarization. Nevertheless, questions whether such corner solutions are adequate for developing countries are rising of late. "Fear of floating" is still conspicuous in many developing countries having adopted nominally a free-floating exchange rate regime. Developing countries are sensitive to exchange rate fluctuations because the cost of exchange rate volatility is greater than the benefit when compared to developed countries. Monitoring bands is a compromise solution, but it still needs further enhancement of estimation techniques for fundamental equilibrium exchange rates in order to make those estimation results more workable in practice. Other alternatives include the creation of soft peg of the G-3 currencies. Despite counterarguments, the stability of G-3 currencies could prove to be beneficial to emerging market economies.
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.
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.
Physical Equilibrium Evaluation in Parkinson Disease
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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.
Modelling shelf-ocean exchange and its biogeochemical consequences in coastal upwelling systems
DEFF Research Database (Denmark)
Muchamad, Al Azhar
The biogeochemical cycles of organic carbon, nutrients, oxygen, and sulfur in the oceans have been suggested to dominantly occur across the shelf–ocean transition over the continental margin, although this zone represents only a small percentage of the global ocean area. Coastal upwelling zones...... in eastern boundary upwelling systems is an example of the most productive ocean waters over continental margins where intense supply of nutrients occur from deeper ocean waters. Interesting questions arise related to the biogeochemical cycles in such upwelling systems; such as 1) how the recently observed...... these questions centering on shelf–ocean exchange and biogeochemical cycle in the coastal upwelling systems under oxic and anoxic conditions. Firstly, I developed a new biogeochemical model which resolves coupling between cycles of the elements nitrogen, oxygen, phosphate, and sulfur by considering several key...
A MODEL OF HETEROGENEOUS DISTRIBUTED SYSTEM FOR FOREIGN EXCHANGE PORTFOLIO ANALYSIS
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Dragutin Kermek
2006-06-01
Full Text Available The paper investigates the design of heterogeneous distributed system for foreign exchange portfolio analysis. The proposed model includes few separated and dislocated but connected parts through distributed mechanisms. Making system distributed brings new perspectives to performance busting where software based load balancer gets very important role. Desired system should spread over multiple, heterogeneous platforms in order to fulfil open platform goal. Building such a model incorporates different patterns from GOF design patterns, business patterns, J2EE patterns, integration patterns, enterprise patterns, distributed design patterns to Web services patterns. The authors try to find as much as possible appropriate patterns for planned tasks in order to capture best modelling and programming practices.
Exchange bias training effect in coupled all ferromagnetic bilayer structures.
Binek, Ch; Polisetty, S; He, Xi; Berger, A
2006-02-17
Exchange coupled bilayers of soft and hard ferromagnetic thin films show remarkable analogies to conventional antiferromagnetic/ferromagnetic exchange bias heterostructures. Not only do all these ferromagnetic bilayers exhibit a tunable exchange bias effect, they also show a distinct training behavior upon cycling the soft layer through consecutive hysteresis loops. In contrast with conventional exchange bias systems, such all ferromagnetic bilayer structures allow the observation of training induced changes in the bias-setting hardmagnetic layer by means of simple magnetometry. Our experiments show unambiguously that the exchange bias training effect is driven by deviations from equilibrium in the pinning layer. A comparison of our experimental data with predictions from a theory based upon triggered relaxation phenomena shows excellent agreement.