Directory of Open Access Journals (Sweden)
Leonid M. Martyushev
2015-06-01
Full Text Available The entropy production (inside the volume bounded by a photosphere of main-sequence stars, subgiants, giants, and supergiants is calculated based on B–V photometry data. A non-linear inverse relationship of thermodynamic fluxes and forces as well as an almost constant specific (per volume entropy production of main-sequence stars (for 95% of stars, this quantity lies within 0.5 to 2.2 of the corresponding solar magnitude is found. The obtained results are discussed from the perspective of known extreme principles related to entropy production.
Minimum entropy production principle
Czech Academy of Sciences Publication Activity Database
Maes, C.; Netočný, Karel
2013-01-01
Roč. 8, č. 7 (2013), s. 9664-9677 ISSN 1941-6016 Institutional support: RVO:68378271 Keywords : MINEP Subject RIV: BE - Theoretical Physics http://www.scholarpedia.org/article/Minimum_entropy_production_principle
Entropy production and rectification efficiency in colloid transport along a pulsating channel
Florencia Carusela, M.; Rubi, J. Miguel
2018-06-01
We study the current rectification of particles moving in a pulsating channel under the influence of an applied force. We have shown the existence of different rectification scenarios in which entropic and energetic effects compete. The effect can be quantified by means of a rectification coefficient that is analyzed in terms of the force, the frequency and the diffusion coefficient. The energetic cost of the motion of the particles expressed in terms of the entropy production depends on the importance of the entropic contribution to the total force. Rectification is more important at low values of the applied force when entropic effects become dominant. In this regime, the entropy production is not invariant under reversal of the applied force. The phenomenon observed could be used to optimize transport in microfluidic devices or in biological channels.
Entropy Production in Stochastics
Directory of Open Access Journals (Sweden)
Demetris Koutsoyiannis
2017-10-01
Full Text Available While the modern definition of entropy is genuinely probabilistic, in entropy production the classical thermodynamic definition, as in heat transfer, is typically used. Here we explore the concept of entropy production within stochastics and, particularly, two forms of entropy production in logarithmic time, unconditionally (EPLT or conditionally on the past and present having been observed (CEPLT. We study the theoretical properties of both forms, in general and in application to a broad set of stochastic processes. A main question investigated, related to model identification and fitting from data, is how to estimate the entropy production from a time series. It turns out that there is a link of the EPLT with the climacogram, and of the CEPLT with two additional tools introduced here, namely the differenced climacogram and the climacospectrum. In particular, EPLT and CEPLT are related to slopes of log-log plots of these tools, with the asymptotic slopes at the tails being most important as they justify the emergence of scaling laws of second-order characteristics of stochastic processes. As a real-world application, we use an extraordinary long time series of turbulent velocity and show how a parsimonious stochastic model can be identified and fitted using the tools developed.
Equipartition of entropy production
International Nuclear Information System (INIS)
Tondeur, D.
1990-01-01
This paper deals with the optimal design or operation of heat and mass transfer processes and develops the following conjecture: for a given duty, the best configuration of the process is that in which the entropy production rate is most uniformly distributed. This principle is first analyzed in detail on the simple example of tubular heat exchangers, and within the framework of linear irreversible thermodynamics. A main result is established, which states that the total entropy production is minimal when the local production is uniformly distributed (equipartition). Corollaries then result, which relate the entropy production and the variance of its distribution to economic factors such as the duty, the exchange area, the fluid flow-rates, and the temperature changes. The equipartition principle is then extended to multiple independent variables (time and space), multicomponent transfer, and non-linear but concave flux vs force relationship. Chemical Engineering examples are discussed, where the equipartition property has been applied implicitly or explicitly: design of distillation plates, cyclic distillation, optimal state of feed, and flow-sheets in chromatographic separations. Finally, a generalization of the equipartition principle is proposed, for systems with a distributed design variable (such as the size of the various elements of a system). The optimal distribution of investment is such that the investment in each element (properly amortized) is equal to the cost of irreversible energy degradation in this element. This is equivalent to saying that the ratio of these two quantities is uniformly distributed over the system, and reduces to equipartition of entropy production when the cost factors are constant over the whole system
Entropy equilibrium equation and dynamic entropy production in environment liquid
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
The entropy equilibrium equation is the basis of the nonequilibrium state thermodynamics. But the internal energy implies the kinetic energy of the fluid micelle relative to mass center in the classical entropy equilibrium equation at present. This internal energy is not the mean kinetic energy of molecular movement in thermodynamics. Here a modified entropy equilibrium equation is deduced, based on the concept that the internal energy is just the mean kinetic energy of the molecular movement. A dynamic entropy production is introduced into the entropy equilibrium equation to describe the dynamic process distinctly. This modified entropy equilibrium equation can describe not only the entropy variation of the irreversible processes but also the reversible processes in a thermodynamic system. It is more reasonable and suitable for wider applications.
Fractal Structure and Entropy Production within the Central Nervous System
Directory of Open Access Journals (Sweden)
Andrew J. E. Seely
2014-08-01
Full Text Available Our goal is to explore the relationship between two traditionally unrelated concepts, fractal structure and entropy production, evaluating both within the central nervous system (CNS. Fractals are temporal or spatial structures with self-similarity across scales of measurement; whereas entropy production represents the necessary exportation of entropy to our environment that comes with metabolism and life. Fractals may be measured by their fractal dimension; and human entropy production may be estimated by oxygen and glucose metabolism. In this paper, we observe fractal structures ubiquitously present in the CNS, and explore a hypothetical and unexplored link between fractal structure and entropy production, as measured by oxygen and glucose metabolism. Rapid increase in both fractal structures and metabolism occur with childhood and adolescent growth, followed by slow decrease during aging. Concomitant increases and decreases in fractal structure and metabolism occur with cancer vs. Alzheimer’s and multiple sclerosis, respectively. In addition to fractals being related to entropy production, we hypothesize that the emergence of fractal structures spontaneously occurs because a fractal is more efficient at dissipating energy gradients, thus maximizing entropy production. Experimental evaluation and further understanding of limitations and necessary conditions are indicated to address broad scientific and clinical implications of this work.
Entropy and Entropy Production: Old Misconceptions and New Breakthroughs
Directory of Open Access Journals (Sweden)
Leonid M. Martyushev
2013-03-01
Full Text Available Persistent misconceptions existing for dozens of years and influencing progress in various fields of science are sometimes encountered in the scientific and especially, the popular-science literature. The present brief review deals with two such interrelated misconceptions (misunderstandings. The first misunderstanding: entropy is a measure of disorder. This is an old and very common opinion. The second misconception is that the entropy production minimizes in the evolution of nonequilibrium systems. However, as it has recently become clear, evolution (progress in Nature demonstrates the opposite, i.e., maximization of the entropy production. The principal questions connected with this maximization are considered herein. The two misconceptions mentioned above can lead to the apparent contradiction between the conclusions of modern thermodynamics and the basic conceptions of evolution existing in biology. In this regard, the analysis of these issues seems extremely important and timely as it contributes to the deeper understanding of the laws of development of the surrounding World and the place of humans in it.
Gradient Dynamics and Entropy Production Maximization
Janečka, Adam; Pavelka, Michal
2018-01-01
We compare two methods for modeling dissipative processes, namely gradient dynamics and entropy production maximization. Both methods require similar physical inputs-how energy (or entropy) is stored and how it is dissipated. Gradient dynamics describes irreversible evolution by means of dissipation potential and entropy, it automatically satisfies Onsager reciprocal relations as well as their nonlinear generalization (Maxwell-Onsager relations), and it has statistical interpretation. Entropy production maximization is based on knowledge of free energy (or another thermodynamic potential) and entropy production. It also leads to the linear Onsager reciprocal relations and it has proven successful in thermodynamics of complex materials. Both methods are thermodynamically sound as they ensure approach to equilibrium, and we compare them and discuss their advantages and shortcomings. In particular, conditions under which the two approaches coincide and are capable of providing the same constitutive relations are identified. Besides, a commonly used but not often mentioned step in the entropy production maximization is pinpointed and the condition of incompressibility is incorporated into gradient dynamics.
The Gibbs entropy production in general relativity
International Nuclear Information System (INIS)
Henneaux, M.
1983-01-01
The entropy production is analyzed in the case of homogeneous cosmological models of the Bianchi type. It is shown to vanish for class-A models and to be undefined for class-B ones, because of an ambiguity in the measure on the space of the true gravitational degrees of freedom. How this results extend to the full Einstein theory is discussed
Gibbs entropy production in general relativity
International Nuclear Information System (INIS)
Henneaux, M.
1983-01-01
The entropy production is analyzed in the case of homogeneous cosmological models of the Bianchi type. It is shown to vanish for class-A models and to be undefined for class-B ones, because of an ambiguity in the measure on the space of the true gravitational degrees of freedom. How this results extends to the full Einstein theory is discussed
Minimization of entropy production in separate and connected process units
Energy Technology Data Exchange (ETDEWEB)
Roesjorde, Audun
2004-08-01
The objective of this thesis was to further develop a methodology for minimizing the entropy production of single and connected chemical process units. When chemical process equipment is designed and operated at the lowest entropy production possible, the energy efficiency of the equipment is enhanced. We have found for single process units that the entropy production could be reduced with up to 20-40%, given the degrees of freedom in the optimization. In processes, our results indicated that even bigger reductions were possible. The states of minimum entropy production were studied and important painter's for obtaining significant reductions in the entropy production were identified. Both from sustain ability and economical viewpoints knowledge of energy efficient design and operation are important. In some of the systems we studied, nonequilibrium thermodynamics was used to model the entropy production. In Chapter 2, we gave a brief introduction to different industrial applications of nonequilibrium thermodynamics. The link between local transport phenomena and overall system description makes nonequilibrium thermodynamics a useful tool for understanding design of chemical process units. We developed the methodology of minimization of entropy production in several steps. First, we analyzed and optimized the entropy production of single units: Two alternative concepts of adiabatic distillation; diabatic and heat-integrated distillation, were analyzed and optimized in Chapter 3 to 5. In diabatic distillation, heat exchange is allowed along the column, and it is this feature that increases the energy efficiency of the distillation column. In Chapter 3, we found how a given area of heat transfer should be optimally distributed among the trays in a column separating a mixture of propylene and propane. The results showed that heat exchange was most important on the trays close to the re boiler and condenser. In Chapter 4 and 5, we studied how the entropy
Maximum entropy production rate in quantum thermodynamics
Energy Technology Data Exchange (ETDEWEB)
Beretta, Gian Paolo, E-mail: beretta@ing.unibs.i [Universita di Brescia, via Branze 38, 25123 Brescia (Italy)
2010-06-01
In the framework of the recent quest for well-behaved nonlinear extensions of the traditional Schroedinger-von Neumann unitary dynamics that could provide fundamental explanations of recent experimental evidence of loss of quantum coherence at the microscopic level, a recent paper [Gheorghiu-Svirschevski 2001 Phys. Rev. A 63 054102] reproposes the nonlinear equation of motion proposed by the present author [see Beretta G P 1987 Found. Phys. 17 365 and references therein] for quantum (thermo)dynamics of a single isolated indivisible constituent system, such as a single particle, qubit, qudit, spin or atomic system, or a Bose-Einstein or Fermi-Dirac field. As already proved, such nonlinear dynamics entails a fundamental unifying microscopic proof and extension of Onsager's reciprocity and Callen's fluctuation-dissipation relations to all nonequilibrium states, close and far from thermodynamic equilibrium. In this paper we propose a brief but self-contained review of the main results already proved, including the explicit geometrical construction of the equation of motion from the steepest-entropy-ascent ansatz and its exact mathematical and conceptual equivalence with the maximal-entropy-generation variational-principle formulation presented in Gheorghiu-Svirschevski S 2001 Phys. Rev. A 63 022105. Moreover, we show how it can be extended to the case of a composite system to obtain the general form of the equation of motion, consistent with the demanding requirements of strong separability and of compatibility with general thermodynamics principles. The irreversible term in the equation of motion describes the spontaneous attraction of the state operator in the direction of steepest entropy ascent, thus implementing the maximum entropy production principle in quantum theory. The time rate at which the path of steepest entropy ascent is followed has so far been left unspecified. As a step towards the identification of such rate, here we propose a possible
Improved entropy encoding for high efficient video coding standard
Directory of Open Access Journals (Sweden)
B.S. Sunil Kumar
2018-03-01
Full Text Available The High Efficiency Video Coding (HEVC has better coding efficiency, but the encoding performance has to be improved to meet the growing multimedia applications. This paper improves the standard entropy encoding by introducing the optimized weighing parameters, so that higher rate of compression can be accomplished over the standard entropy encoding. The optimization is performed using the recently introduced firefly algorithm. The experimentation is carried out using eight benchmark video sequences and the PSNR for varying rate of data transmission is investigated. Comparative analysis based on the performance statistics is made with the standard entropy encoding. From the obtained results, it is clear that the originality of the decoded video sequence is preserved far better than the proposed method, though the compression rate is increased. Keywords: Entropy, Encoding, HEVC, PSNR, Compression
The maximum entropy production and maximum Shannon information entropy in enzyme kinetics
Dobovišek, Andrej; Markovič, Rene; Brumen, Milan; Fajmut, Aleš
2018-04-01
We demonstrate that the maximum entropy production principle (MEPP) serves as a physical selection principle for the description of the most probable non-equilibrium steady states in simple enzymatic reactions. A theoretical approach is developed, which enables maximization of the density of entropy production with respect to the enzyme rate constants for the enzyme reaction in a steady state. Mass and Gibbs free energy conservations are considered as optimization constraints. In such a way computed optimal enzyme rate constants in a steady state yield also the most uniform probability distribution of the enzyme states. This accounts for the maximal Shannon information entropy. By means of the stability analysis it is also demonstrated that maximal density of entropy production in that enzyme reaction requires flexible enzyme structure, which enables rapid transitions between different enzyme states. These results are supported by an example, in which density of entropy production and Shannon information entropy are numerically maximized for the enzyme Glucose Isomerase.
Entropy production in a cell and reversal of entropy flow as an anticancer therapy
Institute of Scientific and Technical Information of China (English)
Liao-fu LUO
2009-01-01
The entropy production rate of cancer cells is always higher than healthy cells in the case where no external field is applied. Different entropy production between two kinds of cells determines the direction of entropy flow among cells. The entropy flow is the carrier of information flow. The entropy flow from cancerous cells to healthy cells takes along the harmful information of cancerous cells, propagating its toxic action to healthy tissues. We demonstrate that a low-frequency and low- intensity electromagnetic field or ultrasound irradiation may increase the entropy production rate of a cell in normal tissue than that in cancer and consequently re- verse the direction of entropy current between two kinds of cells. The modification of the PH value of cells may also cause the reversal of the direction of entropy flow between healthy and cancerous cells. Therefore, the bio- logical tissue under the irradiation of an electromagnetic field or ultrasound or under the appropriate change of cell acidity can avoid the propagation of harmful infor- marion from cancer cells. We suggest that this entropy mechanism possibly provides a basis for a novel approach to anticancer therapy.
Excess Entropy Production in Quantum System: Quantum Master Equation Approach
Nakajima, Satoshi; Tokura, Yasuhiro
2017-12-01
For open systems described by the quantum master equation (QME), we investigate the excess entropy production under quasistatic operations between nonequilibrium steady states. The average entropy production is composed of the time integral of the instantaneous steady entropy production rate and the excess entropy production. We propose to define average entropy production rate using the average energy and particle currents, which are calculated by using the full counting statistics with QME. The excess entropy production is given by a line integral in the control parameter space and its integrand is called the Berry-Sinitsyn-Nemenman (BSN) vector. In the weakly nonequilibrium regime, we show that BSN vector is described by ln \\breve{ρ }_0 and ρ _0 where ρ _0 is the instantaneous steady state of the QME and \\breve{ρ }_0 is that of the QME which is given by reversing the sign of the Lamb shift term. If the system Hamiltonian is non-degenerate or the Lamb shift term is negligible, the excess entropy production approximately reduces to the difference between the von Neumann entropies of the system. Additionally, we point out that the expression of the entropy production obtained in the classical Markov jump process is different from our result and show that these are approximately equivalent only in the weakly nonequilibrium regime.
Entropy-generated power and its efficiency
DEFF Research Database (Denmark)
Golubeva, N.; Imparato, A.; Esposito, M.
2013-01-01
We propose a simple model for a motor that generates mechanical motion by exploiting an entropic force arising from the topology of the underlying phase space. We show that the generation of mechanical forces in our system is surprisingly robust to local changes in kinetic and topological paramet...... parameters. Furthermore, we find that the efficiency at maximum power may show discontinuities....
Frenetic Bounds on the Entropy Production
Maes, Christian
2017-10-01
We give a systematic derivation of positive lower bounds for the expected entropy production (EP) rate in classical statistical mechanical systems obeying a dynamical large deviation principle. The logic is the same for the return to thermodynamic equilibrium as it is for steady nonequilibria working under the condition of local detailed balance. We recover there recently studied "uncertainty" relations for the EP, appearing in studies about the effectiveness of mesoscopic machines. In general our refinement of the positivity of the expected EP rate is obtained in terms of a positive and even function of the expected current(s) which measures the dynamical activity in the system, a time-symmetric estimate of the changes in the system's configuration. Also underdamped diffusions can be included in the analysis.
Conformal Symmetry and Cosmological Entropy Production
Directory of Open Access Journals (Sweden)
Alexander B. Balakin
2002-03-01
Full Text Available Abstract: Introducing an effective refraction index of an isotropic cosmic medium, we investigate the cosmological fluid dynamics which is consistent with a conformal, timelike symmetry of a corresponding "optical" metric. We demonstrate that this kind of symmetry is compatible with the existence of a negative viscous pressure and, consequently, with cosmological entropy production. We establish an exactly solvable model according to which the viscous pressure is a consequence of a self-interacting one-particle force which is self-consistently exerted on the microscopic particles of a relativistic gas. Furthermore, we show that a suficiently high decay rate of the refraction index of an ultrarelativistic cosmic medium results in an in ationary expansion of the universe.
Statistical properties of entropy production derived from fluctuation theorems
International Nuclear Information System (INIS)
Merhav, Neri; Kafri, Yariv
2010-01-01
Several implications of well-known fluctuation theorems, on the statistical properties of entropy production, are studied using various approaches. We begin by deriving a tight lower bound on the variance of the entropy production for a given mean of this random variable. It is shown that the Evans–Searles fluctuation theorem alone imposes a significant lower bound on the variance only when the mean entropy production is very small. It is then nonetheless demonstrated that upon incorporating additional information concerning the entropy production, this lower bound can be significantly improved, so as to capture extensivity properties. Another important aspect of the fluctuation properties of the entropy production is the relationship between the mean and the variance, on the one hand, and the probability of the event where the entropy production is negative, on the other hand. Accordingly, we derive upper and lower bounds on this probability in terms of the mean and the variance. These bounds are tighter than previous bounds that can be found in the literature. Moreover, they are tight in the sense that there exist probability distributions, satisfying the Evans–Searles fluctuation theorem, that achieve them with equality. Finally, we present a general method for generating a wide class of inequalities that must be satisfied by the entropy production. We use this method to derive several new inequalities that go beyond the standard derivation of the second law
Efficiency of crude oil markets: Evidences from informational entropy analysis
International Nuclear Information System (INIS)
Ortiz-Cruz, Alejandro; Rodriguez, Eduardo; Ibarra-Valdez, Carlos; Alvarez-Ramirez, Jose
2012-01-01
The role of crude oil as the main energy source for the global economic activity has motivated the discussion about the dynamics and causes of crude oil price changes. An accurate understanding of the issue should provide important guidelines for the design of optimal policies and government budget planning. Using daily data for WTI over the period January 1986–March 2011, we analyze the evolution of the informational complexity and efficiency for the crude oil market through multiscale entropy analysis. The results indicated that the crude oil market is informationally efficient over the scrutinized period except for two periods that correspond to the early 1990s and late 2000s US recessions. Overall, the results showed that deregulation has improved the operation of the market in the sense of making returns less predictable. On the other hand, there is some evidence that the probability of having a severe US economic recession increases as the informational efficiency decreases, which indicates that returns from crude oil markets are less uncertain during economic downturns. - Highlights: ► Entropy concepts are used to characterize crude oil prices. ► An index of market efficiency is introduced. ► Except for periods of economic recession, the crude oil market is informationally efficient.
International Nuclear Information System (INIS)
Johannessen, Eivind; Rosjorde, Audun
2007-01-01
We show that the theorem of equipartition of entropy production is important for the understanding of the state of minimum entropy production in diabatic distillation. The theorem is not valid in a strictly mathematical sense. We explain why, when and in what sense this theorem is a good approximation to the optimal state in diabatic distillation. In order to make these predictions, we use a hypothesis for the state of minimum entropy production of an optimally controlled system, which was formulated on the basis of results of entropy production minimisation in chemical reactors. The hypothesis says that the state of minimum entropy production is characterised by approximately constant local entropy production and thermodynamic forces, given that there is sufficient freedom in the system. We present numerical results which are in agreement with the predictions. The results show that a column with constant tray entropy production in the stripping section and in the rectifying section is a good approximation to the optimal column, except when the total heat transfer area is low. The agreement between the two columns becomes better and better as the total heat transfer area and the number of trays increase. The fact that the predictions and the numerical results agree very well gives support to the validity of the hypothesis
Analysis of entropy extraction efficiencies in random number generation systems
Wang, Chao; Wang, Shuang; Chen, Wei; Yin, Zhen-Qiang; Han, Zheng-Fu
2016-05-01
Random numbers (RNs) have applications in many areas: lottery games, gambling, computer simulation, and, most importantly, cryptography [N. Gisin et al., Rev. Mod. Phys. 74 (2002) 145]. In cryptography theory, the theoretical security of the system calls for high quality RNs. Therefore, developing methods for producing unpredictable RNs with adequate speed is an attractive topic. Early on, despite the lack of theoretical support, pseudo RNs generated by algorithmic methods performed well and satisfied reasonable statistical requirements. However, as implemented, those pseudorandom sequences were completely determined by mathematical formulas and initial seeds, which cannot introduce extra entropy or information. In these cases, “random” bits are generated that are not at all random. Physical random number generators (RNGs), which, in contrast to algorithmic methods, are based on unpredictable physical random phenomena, have attracted considerable research interest. However, the way that we extract random bits from those physical entropy sources has a large influence on the efficiency and performance of the system. In this manuscript, we will review and discuss several randomness extraction schemes that are based on radiation or photon arrival times. We analyze the robustness, post-processing requirements and, in particular, the extraction efficiency of those methods to aid in the construction of efficient, compact and robust physical RNG systems.
Entropy production analysis of hysteresis characteristic of a pump-turbine model
International Nuclear Information System (INIS)
Li, Deyou; Wang, Hongjie; Qin, Yonglin; Han, Lei; Wei, Xianzhu; Qin, Daqing
2017-01-01
Highlights: • An interesting hysteresis phenomenon was analyzed using entropy production theory. • A function was used to calculate the entropy production in the wall region. • Generation mechanism of the hump and hysteresis characteristics was obtained. - Abstract: The hydraulic loss due to friction and unstable flow patterns in hydro-turbines causes a drop in their efficiency. The traditional method for analyzing the hydraulic loss is by evaluating the pressure drop, which has certain limitations and cannot determine the exact locations at which the high hydraulic loss occurs. In this study, entropy production theory was adopted to obtain a detailed distribution of the hydraulic loss in a pump-turbine in the pump mode. In the past, the wall effects of entropy production were not considered, which caused larger errors as compared with the method of pressure difference. First, a wall equation was proposed to calculate the hydraulic loss in the wall region. The comparison of hydraulic loss calculated by entropy production and pressure difference revealed a better result. Then, through the use of the entropy production theory, the performance characteristics were determined for a pump-turbine with 19 mm guide vane opening, and the variation in the entropy production was obtained. Recently, an interesting phenomenon, i.e., a hysteresis characteristic, was observed in the hump region in pump-turbines. Research shows that the hysteresis characteristic is a result of the Euler momentum and hydraulic loss; the hydraulic loss accounts for a major portion of the hysteresis characteristic. Finally, the hysteresis characteristic in the hump region was analyzed in detail through the entropy production. The results showed that the hump characteristic and the accompanying hysteresis phenomenon are caused by backflow at the runner inlet and the presence of separation vortices close to the hub and the shroud in the stay/guide vanes, which is dependent on the direction of
Benfenati, Francesco; Beretta, Gian Paolo
2018-04-01
We show that to prove the Onsager relations using the microscopic time reversibility one necessarily has to make an ergodic hypothesis, or a hypothesis closely linked to that. This is true in all the proofs of the Onsager relations in the literature: from the original proof by Onsager, to more advanced proofs in the context of linear response theory and the theory of Markov processes, to the proof in the context of the kinetic theory of gases. The only three proofs that do not require any kind of ergodic hypothesis are based on additional hypotheses on the macroscopic evolution: Ziegler's maximum entropy production principle (MEPP), the principle of time reversal invariance of the entropy production, or the steepest entropy ascent principle (SEAP).
Institute of Scientific and Technical Information of China (English)
Xie Wen-Xian; Xu Wei; Cai Li
2007-01-01
This paper shows the Fokker-Planck equation of a dynamical system driven by coloured cross-correlated white noises in the absence and presence of a small external force. Based on the Fokker-Planck equation and the definition of Shannon's information entropy, the time dependence of entropy flux and entropy production can be calculated. The present results can be used to explain the extremal behaviour of time dependence of entropy flux and entropy production in view of the dissipative parameter γ of the system, coloured cross-correlation time τ and coloured cross-correlation strength λ.
International Nuclear Information System (INIS)
Guo Yongfeng; Xu Wei; Li Dongxi; Xie Wenxian
2008-01-01
A stochastic dissipative dynamical system driven by non-Gaussian noise is investigated. A general approximate Fokker-Planck equation of the system is derived through a path-integral approach. Based on the definition of Shannon's information entropy, the exact time dependence of entropy flux and entropy production of the system is calculated both in the absence and in the presence of non-equilibrium constraint. The present calculation can be used to interpret the interplay of the dissipative constant and non-Gaussian noise on the entropy flux and entropy production
Entropy production in the relativistic heavy ion collisions
International Nuclear Information System (INIS)
Holme, A.K.; Csernai, L.P.; Levai, P.; Papp, G.
1989-09-01
A short overview is given on the most important possibilities of entropy production in the relativistic heavy ion collisions, which is connected to the shock phenomena. The E802 experiment is considered as an example, where one can determine the specific entropy content from measured strange particle ratios. The received large entropy value (S/N B ∼ 14) can be explained by assuming quark-gluon plasma formation. The possibility of overcooling of quark-gluon plasma and its deflagration are also investigated. (author) 22 refs.; 4 figs
Information Entropy Production of Maximum Entropy Markov Chains from Spike Trains
Directory of Open Access Journals (Sweden)
Rodrigo Cofré
2018-01-01
Full Text Available The spiking activity of neuronal networks follows laws that are not time-reversal symmetric; the notion of pre-synaptic and post-synaptic neurons, stimulus correlations and noise correlations have a clear time order. Therefore, a biologically realistic statistical model for the spiking activity should be able to capture some degree of time irreversibility. We use the thermodynamic formalism to build a framework in the context maximum entropy models to quantify the degree of time irreversibility, providing an explicit formula for the information entropy production of the inferred maximum entropy Markov chain. We provide examples to illustrate our results and discuss the importance of time irreversibility for modeling the spike train statistics.
Energy conservation and maximal entropy production in enzyme reactions.
Dobovišek, Andrej; Vitas, Marko; Brumen, Milan; Fajmut, Aleš
2017-08-01
A procedure for maximization of the density of entropy production in a single stationary two-step enzyme reaction is developed. Under the constraints of mass conservation, fixed equilibrium constant of a reaction and fixed products of forward and backward enzyme rate constants the existence of maximum in the density of entropy production is demonstrated. In the state with maximal density of entropy production the optimal enzyme rate constants, the stationary concentrations of the substrate and the product, the stationary product yield as well as the stationary reaction flux are calculated. The test, whether these calculated values of the reaction parameters are consistent with their corresponding measured values, is performed for the enzyme Glucose Isomerase. It is found that calculated and measured rate constants agree within an order of magnitude, whereas the calculated reaction flux and the product yield differ from their corresponding measured values for less than 20 % and 5 %, respectively. This indicates that the enzyme Glucose Isomerase, considered in a non-equilibrium stationary state, as found in experiments using the continuous stirred tank reactors, possibly operates close to the state with the maximum in the density of entropy production. Copyright © 2017 Elsevier B.V. All rights reserved.
Entropy production and plant transpiration in the Liz catchment
Czech Academy of Sciences Publication Activity Database
Šír, Miloslav; Tesař, Miroslav; Krejča, M.; Weger, J.
2008-01-01
Roč. 1, č. 1 (2008), s. 81-89 ISSN 1802-503X Grant - others:MŠMT(CZ) 2B06132 Institutional research plan: CEZ:AV0Z20600510 Keywords : plant transpiration * phytomass productivity * heat balance * entropy production Subject RIV: DA - Hydrology ; Limnology
Entropy Production in Pipeline Flow of Dispersions of Water in Oil
Directory of Open Access Journals (Sweden)
Rajinder Pal
2014-08-01
Full Text Available Entropy production in pipeline adiabatic flow of water-in-oil emulsions is investigated experimentally in three different diameter pipes. The dispersed-phase (water droplets concentration of emulsion is varied from 0 to 41% vol. The entropy production rates in emulsion flow are compared with the values expected in single-phase flow of Newtonian fluids with the same properties (viscosity and density. While in the laminar regime the entropy production rates in emulsion flow can be described adequately by the single-phase Newtonian equations, a significant deviation from single-phase flow behavior is observed in the turbulent regime. In the turbulent regime, the entropy production rates in emulsion flow are found to be substantially smaller than those expected on the basis of single-phase equations. For example, the entropy production rate in water-in-oil emulsion flow at a dispersed-phase volume fraction of 0.41 is only 38.4% of that observed in flow of a single-phase Newtonian fluid with the same viscosity and density, when comparison is made at a Reynolds number of 4000. Thus emulsion flow in pipelines is more efficient thermodynamically than single-phase Newtonian flow.
Entropy production of a Brownian ellipsoid in the overdamped limit.
Marino, Raffaele; Eichhorn, Ralf; Aurell, Erik
2016-01-01
We analyze the translational and rotational motion of an ellipsoidal Brownian particle from the viewpoint of stochastic thermodynamics. The particle's Brownian motion is driven by external forces and torques and takes place in an heterogeneous thermal environment where friction coefficients and (local) temperature depend on space and time. Our analysis of the particle's stochastic thermodynamics is based on the entropy production associated with single particle trajectories. It is motivated by the recent discovery that the overdamped limit of vanishing inertia effects (as compared to viscous fricion) produces a so-called "anomalous" contribution to the entropy production, which has no counterpart in the overdamped approximation, when inertia effects are simply discarded. Here we show that rotational Brownian motion in the overdamped limit generates an additional contribution to the "anomalous" entropy. We calculate its specific form by performing a systematic singular perturbation analysis for the generating function of the entropy production. As a side result, we also obtain the (well-known) equations of motion in the overdamped limit. We furthermore investigate the effects of particle shape and give explicit expressions of the "anomalous entropy" for prolate and oblate spheroids and for near-spherical Brownian particles.
International Nuclear Information System (INIS)
Csernai, L.P.; Lukacs, B.
1984-04-01
In a fluid-dynamical model the extra entropy production is calculated which arises from a non-equilibrium phase transition from nuclear to quark matter. The dynamics of processes producing extra entropy are treated in linear approximation. It is shown that there is a considerable extra entropy production provided the transition is not too fast. In measuring the entropy at the break-up, an excess entropy might signalize the phase transition to a transient quark-gluon plasma. (D.Gy.)
Configurational entropy and ρ and ϕ mesons production in QCD
Karapetyan, G.
2018-06-01
In the present work the electroproduction for diffractive ρ and ϕ mesons by considering AdS/QCD correspondence and Color Glass Condensate (CGC) approximation are studied with respect to the associated dipole cross section, whose parameters are studied and analysed in the framework of the configurational entropy. Our results suggest different quantum states of the nuclear matter, showing that the extremal points of the nuclear configurational entropy is able to reflect a true description of the ρ and ϕ mesons production, using current data concerning light quark masses. During the computations parameters, obtained in fitting procedure, coincide to the experimental within ∼ 0.1%.
Entropy Production and Fluctuation Theorems for Active Matter
Mandal, Dibyendu; Klymko, Katherine; DeWeese, Michael R.
2017-12-01
Active biological systems reside far from equilibrium, dissipating heat even in their steady state, thus requiring an extension of conventional equilibrium thermodynamics and statistical mechanics. In this Letter, we have extended the emerging framework of stochastic thermodynamics to active matter. In particular, for the active Ornstein-Uhlenbeck model, we have provided consistent definitions of thermodynamic quantities such as work, energy, heat, entropy, and entropy production at the level of single, stochastic trajectories and derived related fluctuation relations. We have developed a generalization of the Clausius inequality, which is valid even in the presence of the non-Hamiltonian dynamics underlying active matter systems. We have illustrated our results with explicit numerical studies.
Modeling Electric Discharges with Entropy Production Rate Principles
Directory of Open Access Journals (Sweden)
Thomas Christen
2009-12-01
Full Text Available Under which circumstances are variational principles based on entropy production rate useful tools for modeling steady states of electric (gas discharge systems far from equilibrium? It is first shown how various different approaches, as Steenbeck’s minimum voltage and Prigogine’s minimum entropy production rate principles are related to the maximum entropy production rate principle (MEPP. Secondly, three typical examples are discussed, which provide a certain insight in the structure of the models that are candidates for MEPP application. It is then thirdly argued that MEPP, although not being an exact physical law, may provide reasonable model parameter estimates, provided the constraints contain the relevant (nonlinear physical effects and the parameters to be determined are related to disregarded weak constraints that affect mainly global entropy production. Finally, it is additionally conjectured that a further reason for the success of MEPP in certain far from equilibrium systems might be based on a hidden linearity of the underlying kinetic equation(s.
Fisher-Renyi entropy product and information plane
International Nuclear Information System (INIS)
Romera, E.; Nagy, A.
2008-01-01
Connection between Fisher information and Renyi entropy has been established. This link allows us to define the Fisher-Renyi information plane and an entropic product in terms of these quantities. New Renyi uncertainty relations are obtained for single particle densities of many particle systems in position-momentum conjugate spaces
Minimum entropy production principle from a dynamical fluctuation law
Czech Academy of Sciences Publication Activity Database
Maes, C.; Netočný, Karel
2007-01-01
Roč. 48, č. 5 (2007), 053306/1-053306/12 ISSN 0022-2488 R&D Projects: GA ČR GA202/07/0404 Institutional research plan: CEZ:AV0Z10100520 Keywords : dynamical fluctuations * entropy production Subject RIV: BE - Theoretical Physics Impact factor: 1.137, year: 2007
Directory of Open Access Journals (Sweden)
Hang Liu
2016-08-01
Full Text Available In this paper, we investigate the angular momentum independence of the entropy sum and product for AdS rotating black holes based on the first law of thermodynamics and a mathematical lemma related to Vandermonde determinant. The advantage of this method is that the explicit forms of the spacetime metric, black hole mass and charge are not needed but the Hawking temperature and entropy formula on the horizons are necessary for static black holes, while our calculations require the expressions of metric and angular velocity formula. We find that the entropy sum is always independent of angular momentum for all dimensions and the angular momentum-independence of entropy product only holds for the dimensions d>4 with at least one rotation parameter ai=0, while the mass-free of entropy sum and entropy product for rotating black holes only stand for higher dimensions (d>4 and for all dimensions, respectively. On the other hand, we find that the introduction of a negative cosmological constant does not affect the angular momentum-free of entropy sum and product but the criterion for angular momentum-independence of entropy product will be affected.
Thermodynamics, Entropy, Information and the Efficiency of Solar Cells
Abrams, Zeev R.
For well over 50 years, the limits to photovoltaic energy conversion have been known and codified, and have played a vital role in the push for technological breakthroughs to reach—and even attempt to surpass—those limits. This limit, known as the Shockley-Queisser detailed-balance limit, was found by using only the most basic of thermodynamic assumptions, and therefore provides an upper bound that is difficult to contest without violating the laws of thermodynamics. Many different schemes have been devised to improve a solar cell's efficiency beyond this limit, with various benefits and drawbacks for each method. Since the field of solar cell research has been analyzed and dissected for so long by a large variety of researchers, it is quite hard to say or discover anything new without repeating the work of the past. The approach taken in this work is to analyze solar cells from the joint perspective of thermodynamics and information theory. These two subjects have recently been appreciated to be highly interrelated, and using the formalism of Missing Information, we can differentiate between different novel technologies, as well as devise new limits for new and existing methodologies. In this dissertation, the fundamentals of photovoltaic conversion are analyzed from the most basic of principles, emphasizing the thermodynamic parameters of the photovoltaic process. In particular, an emphasis is made on the voltage of the device, as opposed to the current. This emphasis is made since there is a direct relation between the open-circuit voltage of a solar cell and the fundamental equations of thermodynamics and the Free Energy of the system. Moreover, this relation extends to the entropy of the system, which subsequently relates to the field of Information Theory. By focusing on the voltage instead of the current, realizations are made that are not obvious to the majority or researchers in the field, and in particular to efforts of surpassing the Shockley
Stochastic thermodynamics and entropy production of chemical reaction systems
Tomé, Tânia; de Oliveira, Mário J.
2018-06-01
We investigate the nonequilibrium stationary states of systems consisting of chemical reactions among molecules of several chemical species. To this end, we introduce and develop a stochastic formulation of nonequilibrium thermodynamics of chemical reaction systems based on a master equation defined on the space of microscopic chemical states and on appropriate definitions of entropy and entropy production. The system is in contact with a heat reservoir and is placed out of equilibrium by the contact with particle reservoirs. In our approach, the fluxes of various types, such as the heat and particle fluxes, play a fundamental role in characterizing the nonequilibrium chemical state. We show that the rate of entropy production in the stationary nonequilibrium state is a bilinear form in the affinities and the fluxes of reaction, which are expressed in terms of rate constants and transition rates, respectively. We also show how the description in terms of microscopic states can be reduced to a description in terms of the numbers of particles of each species, from which follows the chemical master equation. As an example, we calculate the rate of entropy production of the first and second Schlögl reaction models.
Entropy production of stationary diffusions on non-compact Riemannian manifolds
Institute of Scientific and Technical Information of China (English)
龚光鲁; 钱敏平
1997-01-01
The closed form of the entropy production of stationary diffusion processes with bounded Nelson’s current velocity is given.The limit of the entropy productions of a sequence of reflecting diffusions is also discussed.
Non-equilibrium Dynamics, Thermalization and Entropy Production
International Nuclear Information System (INIS)
Hinrichsen, Haye; Janotta, Peter; Gogolin, Christian
2011-01-01
This paper addresses fundamental aspects of statistical mechanics such as the motivation of a classical state space with spontaneous transitions, the meaning of non-equilibrium in the context of thermalization, and the justification of these concepts from the quantum-mechanical point of view. After an introductory part we focus on the problem of entropy production in non-equilibrium systems. In particular, the generally accepted formula for entropy production in the environment is analyzed from a critical perspective. It is shown that this formula is only valid in the limit of separated time scales of the system's and the environmental degrees of freedom. Finally, we present an alternative simple proof of the fluctuation theorem.
Application of the maximum entropy production principle to electrical systems
International Nuclear Information System (INIS)
Christen, Thomas
2006-01-01
For a simple class of electrical systems, the principle of the maximum entropy production rate (MaxEP) is discussed. First, we compare the MaxEP principle and the principle of the minimum entropy production rate and illustrate the superiority of the MaxEP principle for the example of two parallel constant resistors. Secondly, we show that the Steenbeck principle for the electric arc as well as the ohmic contact behaviour of space-charge limited conductors follow from the MaxEP principle. In line with work by Dewar, the investigations seem to suggest that the MaxEP principle can also be applied to systems far from equilibrium, provided appropriate information is available that enters the constraints of the optimization problem. Finally, we apply the MaxEP principle to a mesoscopic system and show that the universal conductance quantum, e 2 /h, of a one-dimensional ballistic conductor can be estimated
Efficient use of correlation entropy for analysing time series data
Indian Academy of Sciences (India)
Abstract. The correlation dimension D2 and correlation entropy K2 are both important quantifiers in nonlinear time series analysis. However, use of D2 has been more common compared to K2 as a discriminating measure. One reason for this is that D2 is a static measure and can be easily evaluated from a time series.
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
In this paper the author presents an overview on his own research works. More than ten years ago, we proposed a new fundamental equation of nonequilibrium statistical physics in place of the present Liouville equation. That is the stochastic velocity type’s Langevin equation in 6N dimensional phase space or its equivalent Liouville diffusion equation. This equation is time-reversed asymmetrical. It shows that the form of motion of particles in statistical thermodynamic systems has the drift-diffusion duality, and the law of motion of statistical thermodynamics is expressed by a superposition of both the law of dynamics and the stochastic velocity and possesses both determinism and probability. Hence it is different from the law of motion of particles in dynamical systems. The stochastic diffusion motion of the particles is the microscopic origin of macroscopic irreversibility. Starting from this fundamental equation the BBGKY diffusion equation hierarchy, the Boltzmann collision diffusion equation, the hydrodynamic equations such as the mass drift-diffusion equation, the Navier-Stokes equation and the thermal conductivity equation have been derived and presented here. What is more important, we first constructed a nonlinear evolution equation of nonequilibrium entropy density in 6N, 6 and 3 dimensional phase space, predicted the existence of entropy diffusion. This entropy evolution equation plays a leading role in nonequilibrium entropy theory, it reveals that the time rate of change of nonequilibrium entropy density originates together from its drift, diffusion and production in space. From this evolution equation, we presented a formula for entropy production rate (i.e. the law of entropy increase) in 6N and 6 dimensional phase space, proved that internal attractive force in nonequilibrium system can result in entropy decrease while internal repulsive force leads to another entropy increase, and derived a common expression for this entropy decrease rate or
Entropy production for closed, open and third-kind systems
Energy Technology Data Exchange (ETDEWEB)
Sertorio, L.; Tinetti, G. [Turin Univ. (Italy). Dipt. di Fisica Teorica
1999-07-01
The authors refer to nonequilibrium thermodynamics where the concept of entropy production in defined. Remember that the formalism of equilibrium thermodynamics describes reversible transformations; in this formalism entropy is a state function, for a infinitesimal transformation they have dS=dQ{sub r}ev/T, entropy grows if heat is received, diminishes if heat is released and remains unchanged if the transformation is adiabatic, dQ=O. The formulation of nonequilibrium thermodynamic is not unique, they are two version, one discrete and one continuous: 1) Onsager formulation (1): ordinary differential equations. 2) Landau formulation (2): irreversible field theory. The two formulations do not differ in physical content, in fact the discrete formalism can be considered as a reduction of the continuous formalism and conversely the discrete formalism can be generalised to the continuous one, The continuous, or field theoretical approach, has the advantage that it leads to a spontaneous extension to the relativistic formalism (2). Regardless of the choice 1. or 2., in nonequilibrium thermodynamics any irreversibility is taken into account explicitly, the irreversible event begin: heat diffusion, viscosity and chemical reactions. The distinction among close and open systems applies to equilibrium and nonequilibrium thermodynamics as well.
Evaluation of the Atmospheric Chemical Entropy Production of Mars
Directory of Open Access Journals (Sweden)
Alfonso Delgado-Bonal
2015-07-01
Full Text Available Thermodynamic disequilibrium is a necessary situation in a system in which complex emergent structures are created and maintained. It is known that most of the chemical disequilibrium, a particular type of thermodynamic disequilibrium, in Earth’s atmosphere is a consequence of life. We have developed a thermochemical model for the Martian atmosphere to analyze the disequilibrium by chemical reactions calculating the entropy production. It follows from the comparison with the Earth atmosphere that the magnitude of the entropy produced by the recombination reaction forming O3 (O + O2 + CO2 ⥦ O3 + CO2 in the atmosphere of the Earth is larger than the entropy produced by the dominant set of chemical reactions considered for Mars, as a consequence of the low density and the poor variety of species of the Martian atmosphere. If disequilibrium is needed to create and maintain self-organizing structures in a system, we conclude that the current Martian atmosphere is unable to support large physico-chemical structures, such as those created on Earth.
Productivity and energy efficiency
Energy Technology Data Exchange (ETDEWEB)
Lovins, H. [Rocky Mountain Inst., Snowmass, CO (United States)
1995-12-31
Energy efficient building and office design offers the possibility of significantly increased worker productivity. By improving lighting, heating and cooling, workers can be made more comfortable and productive. An increase of 1 percent in productivity can provide savings to a company that exceed its entire energy bill. Efficient design practices are cost effective just from their energy savings. The resulting productivity gains make them indispensable. This paper documents eight cases in which efficient lighting, heating, and cooling have measurably increased worker productivity, decreased absenteeism, and/or improved the quality of work performed. They also show that efficient lighting can measurably increase work quality by removing errors and manufacturing defects. The case studies presented include retrofit of existing buildings and the design of new facilities, and cover a variety of commercial and industrial settings. Each case study identifies the design changes that were most responsible for increased productivity. As the eight case studies illustrate, energy efficient design may be one of the least expensive ways for a business to improve the productivity of its workers and the quality of its product. (author). 15 refs.
Molecular Entropy, Thermal Efficiency, and Designing of Working Fluids for Organic Rankine Cycles
Wang, Jingtao; Zhang, Jin; Chen, Zhiyou
2012-06-01
A shortage of fossil energy sources boosts the utilization of renewable energy. Among numerous novel techniques, recovering energy from low-grade heat sources through power generation via organic Rankine cycles (ORCs) is one of the focuses. Properties of working fluids are crucial for the ORC's performance. Many studies have been done to select proper working fluids or to design new working fluids. However, no researcher has systematically investigated the relationship between molecular structures and thermal efficiencies of various working fluids for an ideal ORC. This paper has investigated the interrelations of molecular structures, molecular entropies, and thermal efficiencies of various working fluids for an ideal ORC. By calculating thermal efficiencies and molecular entropies, we find that the molecular entropy is the most appropriate thermophysical property of a working fluid to determine how much energy can be converted into work and how much cannot in a system. Generally speaking, working fluids with low entropies will generally have high thermal efficiency for an ideal ORC. Based on this understanding, the direct interrelations of molecular structures and entropies provide an explicit interrelation between molecular structures and thermal efficiencies, and thus provide an insightful direction for molecular design of novel working fluids for ORCs.
Memory behaviors of entropy production rates in heat conduction
Li, Shu-Nan; Cao, Bing-Yang
2018-02-01
Based on the relaxation time approximation and first-order expansion, memory behaviors in heat conduction are found between the macroscopic and Boltzmann-Gibbs-Shannon (BGS) entropy production rates with exponentially decaying memory kernels. In the frameworks of classical irreversible thermodynamics (CIT) and BGS statistical mechanics, the memory dependency on the integrated history is unidirectional, while for the extended irreversible thermodynamics (EIT) and BGS entropy production rates, the memory dependences are bidirectional and coexist with the linear terms. When macroscopic and microscopic relaxation times satisfy a specific relationship, the entropic memory dependences will be eliminated. There also exist initial effects in entropic memory behaviors, which decay exponentially. The second-order term are also discussed, which can be understood as the global non-equilibrium degree. The effects of the second-order term are consisted of three parts: memory dependency, initial value and linear term. The corresponding memory kernels are still exponential and the initial effects of the global non-equilibrium degree also decay exponentially.
ENTROPY PRODUCTION IN COLLISIONLESS SYSTEMS. I. LARGE PHASE-SPACE OCCUPATION NUMBERS
International Nuclear Information System (INIS)
Barnes, Eric I.; Williams, Liliya L. R.
2011-01-01
Certain thermal non-equilibrium situations, outside of the astrophysical realm, suggest that entropy production extrema, instead of entropy extrema, are related to stationary states. In an effort to better understand the evolution of collisionless self-gravitating systems, we investigate the role of entropy production and develop expressions for the entropy production rate in two particular statistical families that describe self-gravitating systems. From these entropy production descriptions, we derive the requirements for extremizing the entropy production rate in terms of specific forms for the relaxation function in the Boltzmann equation. We discuss some implications of these relaxation functions and point to future work that will further test this novel thermodynamic viewpoint of collisionless relaxation.
Information Entropy Production of Maximum Entropy Markov Chains from Spike Trains
Cofré, Rodrigo; Maldonado, Cesar
2018-01-01
We consider the maximum entropy Markov chain inference approach to characterize the collective statistics of neuronal spike trains, focusing on the statistical properties of the inferred model. We review large deviations techniques useful in this context to describe properties of accuracy and convergence in terms of sampling size. We use these results to study the statistical fluctuation of correlations, distinguishability and irreversibility of maximum entropy Markov chains. We illustrate these applications using simple examples where the large deviation rate function is explicitly obtained for maximum entropy models of relevance in this field.
On the Bahadur-efficient testing of uniformity by means of entropy
Czech Academy of Sciences Publication Activity Database
Harremoes, P.; Vajda, Igor
2008-01-01
Roč. 54, č. 1 (2008), s. 321-331 ISSN 0018-9448 R&D Projects: GA MŠk(CZ) 1M0572; GA ČR(CZ) GA102/07/1131 Institutional research plan: CEZ:AV0Z10750506 Keywords : Bahadur-efficient testing * power divergence tests * power entropy tests Subject RIV: BD - Theory of Information Impact factor: 3.793, year: 2008 http://library.utia.cas.cz/separaty/2010/SI/vajda-on the bahadur-efficient testing of uniformity by means of entropy.pdf
Entropy, pricing and productivity of pumped-storage
Karakatsanis, Georgios; Tyralis, Hristos; Tzouka, Katerina
2016-04-01
Pumped-storage constitutes today a mature method of bulk electricity storage in the form of hydropower. This bulk electricity storability upgrades the economic value of hydropower as it may mitigate -or even neutralize- stochastic effects deriving from various geophysical and socioeconomic factors, which produce numerous load balance inefficiencies due to increased uncertainty. Pumped-storage further holds a key role for unifying intermittent renewable (i.e. wind, solar) units with controllable non-renewable (i.e. nuclear, coal) fuel electricity generation plants into integrated energy systems. We develop a set of indicators for the measurement of performance of pumped-storage, in terms of the latter's energy and financial contribution to the energy system. More specifically, we use the concept of entropy in order to examine: (1) the statistical features -and correlations- of the energy system's intermittent components and (2) the statistical features of electricity demand prediction deviations. In this way, the macroeconomics of pumped-storage emerges naturally from its statistical features (Karakatsanis et al. 2014). In addition, these findings are combined to actual daily loads. Hence, not only the amount of energy harvested from the pumped-storage component is expected to be important, but the harvesting time as well, as the intraday price of electricity varies significantly. Additionally, the structure of the pumped-storage market proves to be a significant factor as well for the system's energy and financial performance (Paine et al. 2014). According to the above, we aim at postulating a set of general rules on the productivity of pumped-storage for (integrated) energy systems. Keywords: pumped-storage, storability, economic value of hydropower, stochastic effects, uncertainty, energy systems, entropy, intraday electricity price, productivity References 1. Karakatsanis, Georgios et al. (2014), Entropy, pricing and macroeconomics of pumped-storage systems
Ranking DMUs by Comparing DEA Cross-Efficiency Intervals Using Entropy Measures
Directory of Open Access Journals (Sweden)
Tim Lu
2016-12-01
Full Text Available Cross-efficiency evaluation, an extension of data envelopment analysis (DEA, can eliminate unrealistic weighing schemes and provide a ranking for decision making units (DMUs. In the literature, the determination of input and output weights uniquely receives more attentions. However, the problem of choosing the aggressive (minimal or benevolent (maximal formulation for decision-making might still remain. In this paper, we develop a procedure to perform cross-efficiency evaluation without the need to make any specific choice of DEA weights. The proposed procedure takes into account the aggressive and benevolent formulations at the same time, and the choice of DEA weights can then be avoided. Consequently, a number of cross-efficiency intervals is obtained for each DMU. The entropy, which is based on information theory, is an effective tool to measure the uncertainty. We then utilize the entropy to construct a numerical index for DMUs with cross-efficiency intervals. A mathematical program is proposed to find the optimal entropy values of DMUs for comparison. With the derived entropy value, we can rank DMUs accordingly. Two examples are illustrated to show the effectiveness of the idea proposed in this paper.
Maximum entropy production: Can it be used to constrain conceptual hydrological models?
M.C. Westhoff; E. Zehe
2013-01-01
In recent years, optimality principles have been proposed to constrain hydrological models. The principle of maximum entropy production (MEP) is one of the proposed principles and is subject of this study. It states that a steady state system is organized in such a way that entropy production is maximized. Although successful applications have been reported in...
di Liberto, Francesco; Pastore, Raffaele; Peruggi, Fulvio
2011-05-01
When some entropy is transferred, by means of a reversible engine, from a hot heat source to a colder one, the maximum efficiency occurs, i.e. the maximum available work is obtained. Similarly, a reversible heat pumps transfer entropy from a cold heat source to a hotter one with the minimum expense of energy. In contrast, if we are faced with non-reversible devices, there is some lost work for heat engines, and some extra work for heat pumps. These quantities are both related to entropy production. The lost work, i.e. ? , is also called 'degraded energy' or 'energy unavailable to do work'. The extra work, i.e. ? , is the excess of work performed on the system in the irreversible process with respect to the reversible one (or the excess of heat given to the hotter source in the irreversible process). Both quantities are analysed in detail and are evaluated for a complex process, i.e. the stepwise circular cycle, which is similar to the stepwise Carnot cycle. The stepwise circular cycle is a cycle performed by means of N small weights, dw, which are first added and then removed from the piston of the vessel containing the gas or vice versa. The work performed by the gas can be found as the increase of the potential energy of the dw's. Each single dw is identified and its increase, i.e. its increase in potential energy, evaluated. In such a way it is found how the energy output of the cycle is distributed among the dw's. The size of the dw's affects entropy production and therefore the lost and extra work. The distribution of increases depends on the chosen removal process.
Fluctuation theorem for entropy production during effusion of a relativistic ideal gas.
Cleuren, B; Willaert, K; Engel, A; Van den Broeck, C
2008-02-01
The probability distribution of the entropy production for the effusion of a relativistic ideal gas is calculated explicitly. This result is then extended to include particle and antiparticle pair production and annihilation. In both cases, the fluctuation theorem is verified.
International Nuclear Information System (INIS)
Goswami, Gurupada; Mukherjee, Biswajit; Bag, Bidhan Chandra
2005-01-01
We have studied the relaxation of non-Markovian and thermodynamically closed system both in the absence and presence of non-equilibrium constraint in terms of the information entropy flux and entropy production based on the Fokker-Planck and the entropy balance equations. Our calculation shows how the relaxation time depends on noise correlation time. It also considers how the non-equilibrium constraint is affected by system parameters such as noise correlation time, strength of dissipation and frequency of dynamical system. The interplay of non-equilibrium constraint, frictional memory kernel, noise correlation time and frequency of dynamical system reveals the extremum nature of the entropy production
Goswami, Gurupada; Mukherjee, Biswajit; Bag, Bidhan Chandra
2005-06-01
We have studied the relaxation of non-Markovian and thermodynamically closed system both in the absence and presence of non-equilibrium constraint in terms of the information entropy flux and entropy production based on the Fokker-Planck and the entropy balance equations. Our calculation shows how the relaxation time depends on noise correlation time. It also considers how the non-equilibrium constraint is affected by system parameters such as noise correlation time, strength of dissipation and frequency of dynamical system. The interplay of non-equilibrium constraint, frictional memory kernel, noise correlation time and frequency of dynamical system reveals the extremum nature of the entropy production.
Efficient Transfer Entropy Analysis of Non-Stationary Neural Time Series
Vicente, Raul; Díaz-Pernas, Francisco J.; Wibral, Michael
2014-01-01
Information theory allows us to investigate information processing in neural systems in terms of information transfer, storage and modification. Especially the measure of information transfer, transfer entropy, has seen a dramatic surge of interest in neuroscience. Estimating transfer entropy from two processes requires the observation of multiple realizations of these processes to estimate associated probability density functions. To obtain these necessary observations, available estimators typically assume stationarity of processes to allow pooling of observations over time. This assumption however, is a major obstacle to the application of these estimators in neuroscience as observed processes are often non-stationary. As a solution, Gomez-Herrero and colleagues theoretically showed that the stationarity assumption may be avoided by estimating transfer entropy from an ensemble of realizations. Such an ensemble of realizations is often readily available in neuroscience experiments in the form of experimental trials. Thus, in this work we combine the ensemble method with a recently proposed transfer entropy estimator to make transfer entropy estimation applicable to non-stationary time series. We present an efficient implementation of the approach that is suitable for the increased computational demand of the ensemble method's practical application. In particular, we use a massively parallel implementation for a graphics processing unit to handle the computationally most heavy aspects of the ensemble method for transfer entropy estimation. We test the performance and robustness of our implementation on data from numerical simulations of stochastic processes. We also demonstrate the applicability of the ensemble method to magnetoencephalographic data. While we mainly evaluate the proposed method for neuroscience data, we expect it to be applicable in a variety of fields that are concerned with the analysis of information transfer in complex biological, social, and
Directory of Open Access Journals (Sweden)
Hou Hucan
2017-01-01
Full Text Available Inspired by wide application of the second law of thermodynamics to flow and heat transfer devices, local entropy production analysis method was creatively introduced into energy assessment system of centrifugal water pump. Based on Reynolds stress turbulent model and energy equation model, the steady numerical simulation of the whole flow passage of one IS centrifugal pump was carried out. The local entropy production terms were calculated by user defined functions, mainly including wall entropy production, turbulent entropy production, and viscous entropy production. The numerical results indicated that the irreversible energy loss calculated by the local entropy production method agreed well with that calculated by the traditional method but with some deviations which were probably caused by high rotatability and high curvature of impeller and volute. The wall entropy production and turbulent entropy production took up large part of the whole entropy production about 48.61% and 47.91%, respectively, which indicated that wall friction and turbulent fluctuation were the major factors in affecting irreversible energy loss. Meanwhile, the entropy production rate distribution was discussed and compared with turbulent kinetic energy dissipation rate distribution, it showed that turbulent entropy production rate increased sharply at the near wall regions and both distributed more uniformly. The blade region in leading edge near suction side, trailing edge and volute tongue were the main regions to generate irreversible exergy loss. This research broadens a completely new view in evaluating energy loss and further optimizes pump using entropy production minimization.
Multifield stochastic particle production: beyond a maximum entropy ansatz
Energy Technology Data Exchange (ETDEWEB)
Amin, Mustafa A.; Garcia, Marcos A.G.; Xie, Hong-Yi; Wen, Osmond, E-mail: mustafa.a.amin@gmail.com, E-mail: marcos.garcia@rice.edu, E-mail: hxie39@wisc.edu, E-mail: ow4@rice.edu [Physics and Astronomy Department, Rice University, 6100 Main Street, Houston, TX 77005 (United States)
2017-09-01
We explore non-adiabatic particle production for N {sub f} coupled scalar fields in a time-dependent background with stochastically varying effective masses, cross-couplings and intervals between interactions. Under the assumption of weak scattering per interaction, we provide a framework for calculating the typical particle production rates after a large number of interactions. After setting up the framework, for analytic tractability, we consider interactions (effective masses and cross couplings) characterized by series of Dirac-delta functions in time with amplitudes and locations drawn from different distributions. Without assuming that the fields are statistically equivalent, we present closed form results (up to quadratures) for the asymptotic particle production rates for the N {sub f}=1 and N {sub f}=2 cases. We also present results for the general N {sub f} >2 case, but with more restrictive assumptions. We find agreement between our analytic results and direct numerical calculations of the total occupation number of the produced particles, with departures that can be explained in terms of violation of our assumptions. We elucidate the precise connection between the maximum entropy ansatz (MEA) used in Amin and Baumann (2015) and the underlying statistical distribution of the self and cross couplings. We provide and justify a simple to use (MEA-inspired) expression for the particle production rate, which agrees with our more detailed treatment when the parameters characterizing the effective mass and cross-couplings between fields are all comparable to each other. However, deviations are seen when some parameters differ significantly from others. We show that such deviations become negligible for a broad range of parameters when N {sub f}>> 1.
Local Entropy Production in Turbulent Shear Flows: A Tool for Evaluating Heat Transfer Performance
Institute of Scientific and Technical Information of China (English)
H. HERWIG; F. KOCK
2006-01-01
Performance evaluation of heat transfer devices can be based on the overall entropy production in these devices.In our study we therefore provide equations for the systematic and detailed determination of local entropy production due to dissipation of mechanical energy and due to heat conduction, both in turbulent flows. After turbulence modeling has been incorporated for the fluctuating parts the overall entropy production can be determined by integration with respect to the whole flow domain. Since, however, entropy production rates show very steep gradients close to the wall, numerical solutions are far more effective with wall functions for the entropy production terms. These wall functions are mandatory when high Reynolds number turbulence models are used. For turbulent flow in a pipe with an inserted twisted tape as heat transfer promoter it is shown that based on the overall entropy production rate a clear statement from a thermodynamic point of view is possible. For a certain range of twist strength there is a decrease in overall entropy production compared to the case without insert. Also, the optimum twist strength can be determined. This information is unavailable when only pressure drop and heat transfer data are given.
Sadeghi Ghuchani, Mostafa
2018-02-08
This comment argues against the view that cancer cells produce less entropy than normal cells as stated in a recent paper by Marín and Sabater. The basic principle of estimation of entropy production rate in a living cell is discussed, emphasizing the fact that entropy production depends on both the amount of heat exchange during the metabolism and the entropy difference between products and substrates.
Sadeghi Ghuchani, Mostafa
2018-03-01
This comment argues against the view that cancer cells produce less entropy than normal cells as stated in a recent paper by Marín and Sabater. The basic principle of estimation of entropy production rate in a living cell is discussed, emphasizing the fact that entropy production depends on both the amount of heat exchange during the metabolism and the entropy difference between products and substrates.
The mechanics of granitoid systems and maximum entropy production rates.
Hobbs, Bruce E; Ord, Alison
2010-01-13
A model for the formation of granitoid systems is developed involving melt production spatially below a rising isotherm that defines melt initiation. Production of the melt volumes necessary to form granitoid complexes within 10(4)-10(7) years demands control of the isotherm velocity by melt advection. This velocity is one control on the melt flux generated spatially just above the melt isotherm, which is the control valve for the behaviour of the complete granitoid system. Melt transport occurs in conduits initiated as sheets or tubes comprising melt inclusions arising from Gurson-Tvergaard constitutive behaviour. Such conduits appear as leucosomes parallel to lineations and foliations, and ductile and brittle dykes. The melt flux generated at the melt isotherm controls the position of the melt solidus isotherm and hence the physical height of the Transport/Emplacement Zone. A conduit width-selection process, driven by changes in melt viscosity and constitutive behaviour, operates within the Transport Zone to progressively increase the width of apertures upwards. Melt can also be driven horizontally by gradients in topography; these horizontal fluxes can be similar in magnitude to vertical fluxes. Fluxes induced by deformation can compete with both buoyancy and topographic-driven flow over all length scales and results locally in transient 'ponds' of melt. Pluton emplacement is controlled by the transition in constitutive behaviour of the melt/magma from elastic-viscous at high temperatures to elastic-plastic-viscous approaching the melt solidus enabling finite thickness plutons to develop. The system involves coupled feedback processes that grow at the expense of heat supplied to the system and compete with melt advection. The result is that limits are placed on the size and time scale of the system. Optimal characteristics of the system coincide with a state of maximum entropy production rate. This journal is © 2010 The Royal Society
Rényi-Fisher entropy product as a marker of topological phase transitions
Bolívar, J. C.; Nagy, Ágnes; Romera, Elvira
2018-05-01
The combined Rényi-Fisher entropy product of electrons plus holes displays a minimum at the charge neutrality points. The Stam-Rényi difference and the Stam-Rényi uncertainty product of the electrons plus holes, show maxima at the charge neutrality points. Topological quantum numbers capable of detecting the topological insulator and the band insulator phases, are defined. Upper and lower bounds for the position and momentum space Rényi-Fisher entropy products are derived.
On the Bahadur-efficient testing of uniformity by means of entropy
Czech Academy of Sciences Publication Activity Database
Vajda, Igor; Harremoës, P.
2008-01-01
Roč. 54, 1/2 (2008), s. 321-331 ISSN 0018-9448 R&D Projects: GA MŠk(CZ) 1M0572; GA ČR(CZ) GA102/07/1131 Institutional research plan: CEZ:AV0Z10750506 Keywords : Bahadur efficiency * entropy * goodness-of-fit * power divergences * uniformity testing Subject RIV: BD - Theory of Information Impact factor: 3.793, year: 2008
Efficient algorithms and implementations of entropy-based moment closures for rarefied gases
Energy Technology Data Exchange (ETDEWEB)
Schaerer, Roman Pascal, E-mail: schaerer@mathcces.rwth-aachen.de; Bansal, Pratyuksh; Torrilhon, Manuel
2017-07-01
We present efficient algorithms and implementations of the 35-moment system equipped with the maximum-entropy closure in the context of rarefied gases. While closures based on the principle of entropy maximization have been shown to yield very promising results for moderately rarefied gas flows, the computational cost of these closures is in general much higher than for closure theories with explicit closed-form expressions of the closing fluxes, such as Grad's classical closure. Following a similar approach as Garrett et al. (2015) , we investigate efficient implementations of the computationally expensive numerical quadrature method used for the moment evaluations of the maximum-entropy distribution by exploiting its inherent fine-grained parallelism with the parallelism offered by multi-core processors and graphics cards. We show that using a single graphics card as an accelerator allows speed-ups of two orders of magnitude when compared to a serial CPU implementation. To accelerate the time-to-solution for steady-state problems, we propose a new semi-implicit time discretization scheme. The resulting nonlinear system of equations is solved with a Newton type method in the Lagrange multipliers of the dual optimization problem in order to reduce the computational cost. Additionally, fully explicit time-stepping schemes of first and second order accuracy are presented. We investigate the accuracy and efficiency of the numerical schemes for several numerical test cases, including a steady-state shock-structure problem.
Efficient algorithms and implementations of entropy-based moment closures for rarefied gases
International Nuclear Information System (INIS)
Schaerer, Roman Pascal; Bansal, Pratyuksh; Torrilhon, Manuel
2017-01-01
We present efficient algorithms and implementations of the 35-moment system equipped with the maximum-entropy closure in the context of rarefied gases. While closures based on the principle of entropy maximization have been shown to yield very promising results for moderately rarefied gas flows, the computational cost of these closures is in general much higher than for closure theories with explicit closed-form expressions of the closing fluxes, such as Grad's classical closure. Following a similar approach as Garrett et al. (2015) , we investigate efficient implementations of the computationally expensive numerical quadrature method used for the moment evaluations of the maximum-entropy distribution by exploiting its inherent fine-grained parallelism with the parallelism offered by multi-core processors and graphics cards. We show that using a single graphics card as an accelerator allows speed-ups of two orders of magnitude when compared to a serial CPU implementation. To accelerate the time-to-solution for steady-state problems, we propose a new semi-implicit time discretization scheme. The resulting nonlinear system of equations is solved with a Newton type method in the Lagrange multipliers of the dual optimization problem in order to reduce the computational cost. Additionally, fully explicit time-stepping schemes of first and second order accuracy are presented. We investigate the accuracy and efficiency of the numerical schemes for several numerical test cases, including a steady-state shock-structure problem.
Efficient algorithms and implementations of entropy-based moment closures for rarefied gases
Schaerer, Roman Pascal; Bansal, Pratyuksh; Torrilhon, Manuel
2017-07-01
We present efficient algorithms and implementations of the 35-moment system equipped with the maximum-entropy closure in the context of rarefied gases. While closures based on the principle of entropy maximization have been shown to yield very promising results for moderately rarefied gas flows, the computational cost of these closures is in general much higher than for closure theories with explicit closed-form expressions of the closing fluxes, such as Grad's classical closure. Following a similar approach as Garrett et al. (2015) [13], we investigate efficient implementations of the computationally expensive numerical quadrature method used for the moment evaluations of the maximum-entropy distribution by exploiting its inherent fine-grained parallelism with the parallelism offered by multi-core processors and graphics cards. We show that using a single graphics card as an accelerator allows speed-ups of two orders of magnitude when compared to a serial CPU implementation. To accelerate the time-to-solution for steady-state problems, we propose a new semi-implicit time discretization scheme. The resulting nonlinear system of equations is solved with a Newton type method in the Lagrange multipliers of the dual optimization problem in order to reduce the computational cost. Additionally, fully explicit time-stepping schemes of first and second order accuracy are presented. We investigate the accuracy and efficiency of the numerical schemes for several numerical test cases, including a steady-state shock-structure problem.
Institute of Scientific and Technical Information of China (English)
吴金平
1991-01-01
The relation between the excess entropy production criterion of thermodynamic stabilityfor nonequilibrium states and kinetic linear stability principle is discussed. It is shown thatthe condition required by the excess entropy production criterion generally is sufficient, butnot necessary to judge the system stability. The condition required by the excess entropyproduction criterion is stronger than that of the linear stability principle. Only when theproduct matrix between the linearized matrix of kinetic equations and matrix of quadraticform of second-order excess entropy is symmetric, is the condition required by the excessentropy production criterion that the steady steate is asymptotically stable (δ_xP>0) necessaryand sufficient. The counterexample given by Fox to prove that the excess entropy, (δ~2S)ss,is not a Liapunov function is incorrect. Contradictory to his conclusion, the counterexampleis just a positive one that proves that the excess entropy is a Liapunov function. Moreover,the excess entropy production criterion is not limited by symmetric conditions of the linear-ized matrix of kinetic equations. The excess entropy around nonequilibrium steady states,(δ~2S)ss, is a Liapunov function of thermodynamic system.
Use and validity of principles of extremum of entropy production in the study of complex systems
International Nuclear Information System (INIS)
Heitor Reis, A.
2014-01-01
It is shown how both the principles of extremum of entropy production, which are often used in the study of complex systems, follow from the maximization of overall system conductivities, under appropriate constraints. In this way, the maximum rate of entropy production (MEP) occurs when all the forces in the system are kept constant. On the other hand, the minimum rate of entropy production (mEP) occurs when all the currents that cross the system are kept constant. A brief discussion on the validity of the application of the mEP and MEP principles in several cases, and in particular to the Earth’s climate is also presented. -- Highlights: •The principles of extremum of entropy production are not first principles. •They result from the maximization of conductivities under appropriate constraints. •The conditions of their validity are set explicitly. •Some long-standing controversies are discussed and clarified
Work and entropy production in generalised Gibbs ensembles
International Nuclear Information System (INIS)
Perarnau-Llobet, Martí; Riera, Arnau; Gallego, Rodrigo; Wilming, Henrik; Eisert, Jens
2016-01-01
Recent years have seen an enormously revived interest in the study of thermodynamic notions in the quantum regime. This applies both to the study of notions of work extraction in thermal machines in the quantum regime, as well as to questions of equilibration and thermalisation of interacting quantum many-body systems as such. In this work we bring together these two lines of research by studying work extraction in a closed system that undergoes a sequence of quenches and equilibration steps concomitant with free evolutions. In this way, we incorporate an important insight from the study of the dynamics of quantum many body systems: the evolution of closed systems is expected to be well described, for relevant observables and most times, by a suitable equilibrium state. We will consider three kinds of equilibration, namely to (i) the time averaged state, (ii) the Gibbs ensemble and (iii) the generalised Gibbs ensemble, reflecting further constants of motion in integrable models. For each effective description, we investigate notions of entropy production, the validity of the minimal work principle and properties of optimal work extraction protocols. While we keep the discussion general, much room is dedicated to the discussion of paradigmatic non-interacting fermionic quantum many-body systems, for which we identify significant differences with respect to the role of the minimal work principle. Our work not only has implications for experiments with cold atoms, but also can be viewed as suggesting a mindset for quantum thermodynamics where the role of the external heat baths is instead played by the system itself, with its internal degrees of freedom bringing coarse-grained observables to equilibrium. (paper)
Entropy production in a box: Analysis of instabilities in confined hydrothermal systems
Börsing, N.; Wellmann, J. F.; Niederau, J.; Regenauer-Lieb, K.
2017-09-01
We evaluate if the concept of thermal entropy production can be used as a measure to characterize hydrothermal convection in a confined porous medium as a valuable, thermodynamically motivated addition to the standard Rayleigh number analysis. Entropy production has been used widely in the field of mechanical and chemical engineering as a way to characterize the thermodynamic state and irreversibility of an investigated system. Pioneering studies have since adapted these concepts to natural systems, and we apply this measure here to investigate the specific case of hydrothermal convection in a "box-shaped" confined porous medium, as a simplified analog for, e.g., hydrothermal convection in deep geothermal aquifers. We perform various detailed numerical experiments to assess the response of the convective system to changing boundary conditions or domain aspect ratios, and then determine the resulting entropy production for each experiment. In systems close to the critical Rayleigh number, we derive results that are in accordance to the analytically derived predictions. At higher Rayleigh numbers, however, we observe multiple possible convection modes, and the analysis of the integrated entropy production reveals distinct curves of entropy production that provide an insight into the hydrothermal behavior in the system, both for cases of homogeneous materials, as well as for heterogeneous spatial material distributions. We conclude that the average thermal entropy production characterizes the internal behavior of hydrothermal systems with a meaningful thermodynamic measure, and we expect that it can be useful for the investigation of convection systems in many similar hydrogeological and geophysical settings.
Environmental efficiency analysis of power industry in China based on an entropy SBM model
International Nuclear Information System (INIS)
Zhou, Yan; Xing, Xinpeng; Fang, Kuangnan; Liang, Dapeng; Xu, Chunlin
2013-01-01
In order to assess the environmental efficiency of power industry in China, this paper first proposes a new non-radial DEA approach by integrating the entropy weight and the SBM model. This will improve the assessment reliability and reasonableness. Using the model, this study then evaluates the environmental efficiency of the Chinese power industry at the provincial level during 2005–2010. The results show a marked difference in environmental efficiency of the power industry among Chinese provinces. Although the annual, average, environmental efficiency level fluctuates, there is an increasing trend. The Tobit regression analysis reveals the innovation ability of enterprises, the proportion of electricity generated by coal-fired plants and the generation capacity have a significantly positive effect on environmental efficiency. However the waste fees levied on waste discharge and investment in industrial pollutant treatment are negatively associated with environmental efficiency. - Highlights: ► We assess the environmental efficiency of power industry in China by E-SBM model. ► Environmental efficiency of power industry is different among provinces. ► Efficiency stays at a higher level in the eastern and the western area. ► Proportion of coal-fired plants has a positive effect on the efficiency. ► Waste fees and the investment have a negative effect on the efficiency
Toward efficient computation of the expected relative entropy for nonlinear experimental design
International Nuclear Information System (INIS)
Coles, Darrell; Prange, Michael
2012-01-01
The expected relative entropy between prior and posterior model-parameter distributions is a Bayesian objective function in experimental design theory that quantifies the expected gain in information of an experiment relative to a previous state of knowledge. The expected relative entropy is a preferred measure of experimental quality because it can handle nonlinear data-model relationships, an important fact due to the ubiquity of nonlinearity in science and engineering and its effects on post-inversion parameter uncertainty. This objective function does not necessarily yield experiments that mediate well-determined systems, but, being a Bayesian quality measure, it rigorously accounts for prior information which constrains model parameters that may be only weakly constrained by the optimized dataset. Historically, use of the expected relative entropy has been limited by the computing and storage requirements associated with high-dimensional numerical integration. Herein, a bifocal algorithm is developed that makes these computations more efficient. The algorithm is demonstrated on a medium-sized problem of sampling relaxation phenomena and on a large problem of source–receiver selection for a 2D vertical seismic profile. The method is memory intensive but workarounds are discussed. (paper)
ENTROPY PRODUCTION IN COLLISIONLESS SYSTEMS. II. ARBITRARY PHASE-SPACE OCCUPATION NUMBERS
International Nuclear Information System (INIS)
Barnes, Eric I.; Williams, Liliya L. R.
2012-01-01
We present an analysis of two thermodynamic techniques for determining equilibria of self-gravitating systems. One is the Lynden-Bell (LB) entropy maximization analysis that introduced violent relaxation. Since we do not use the Stirling approximation, which is invalid at small occupation numbers, our systems have finite mass, unlike LB's isothermal spheres. (Instead of Stirling, we utilize a very accurate smooth approximation for ln x!.) The second analysis extends entropy production extremization to self-gravitating systems, also without the use of the Stirling approximation. In addition to the LB statistical family characterized by the exclusion principle in phase space, and designed to treat collisionless systems, we also apply the two approaches to the Maxwell-Boltzmann (MB) families, which have no exclusion principle and hence represent collisional systems. We implicitly assume that all of the phase space is equally accessible. We derive entropy production expressions for both families and give the extremum conditions for entropy production. Surprisingly, our analysis indicates that extremizing entropy production rate results in systems that have maximum entropy, in both LB and MB statistics. In other words, both thermodynamic approaches lead to the same equilibrium structures.
Experimental Rectification of Entropy Production by Maxwell's Demon in a Quantum System
Camati, Patrice A.; Peterson, John P. S.; Batalhão, Tiago B.; Micadei, Kaonan; Souza, Alexandre M.; Sarthour, Roberto S.; Oliveira, Ivan S.; Serra, Roberto M.
2016-12-01
Maxwell's demon explores the role of information in physical processes. Employing information about microscopic degrees of freedom, this "intelligent observer" is capable of compensating entropy production (or extracting work), apparently challenging the second law of thermodynamics. In a modern standpoint, it is regarded as a feedback control mechanism and the limits of thermodynamics are recast incorporating information-to-energy conversion. We derive a trade-off relation between information-theoretic quantities empowering the design of an efficient Maxwell's demon in a quantum system. The demon is experimentally implemented as a spin-1 /2 quantum memory that acquires information, and employs it to control the dynamics of another spin-1 /2 system, through a natural interaction. Noise and imperfections in this protocol are investigated by the assessment of its effectiveness. This realization provides experimental evidence that the irreversibility in a nonequilibrium dynamics can be mitigated by assessing microscopic information and applying a feed-forward strategy at the quantum scale.
Eigenvalue and Entropy Statistics for Products of Conjugate Random Quantum Channels
Directory of Open Access Journals (Sweden)
Benoît Collins
2010-06-01
Full Text Available Using the graphical calculus and integration techniques introduced by the authors, we study the statistical properties of outputs of products of random quantum channels for entangled inputs. In particular, we revisit and generalize models of relevance for the recent counterexamples to the minimum output entropy additivity problems. Our main result is a classification of regimes for which the von Neumann entropy is lower on average than the elementary bounds that can be obtained with linear algebra techniques.
From 0 to 5000 in 2 x 10-24 seconds: Entropy production in relativistic heavy-ion collisions
International Nuclear Information System (INIS)
Fries, R.J.; Kunihiro, T.; Mueller, B.; Ohnishi, A.; Schaefer, A.
2009-01-01
We review what is known about the contributions to the final entropy from the different stages of a relativistic nuclear collision, including recent results on the decoherence entropy and the entropy produced during the hydrodynamic phase by viscous effects. We then present a general framework, based on the Husimi distribution function, for the calculation of entropy growth in quantum field theories, which is applicable to the earliest ('glasma') phase of the collision during which most of the entropy is generated. The entropy calculated from the Husimi distribution exhibits linear growth when the quantum field contains unstable modes and is asymptotically equal to the Kolmogorov-Sinai (KS) entropy. We outline how the approach can be used to investigate the problem of entropy production in a relativistic heavy-ion reaction from first principles.
From 0 to 5000 in 2 × 10−24 seconds: Entropy production in relativistic heavy-ion collisions
Energy Technology Data Exchange (ETDEWEB)
Fries, R.; Kunihiro, T.; Muller, B.; Ohnishi, A.; Schafer, A.
2009-11-01
We review what is known about the contributions to the final entropy from the different stages of a relativistic nuclear collision, including recent results on the decoherence entropy and the entropy produced during the hydrodynamic phase by viscous effects. We then present a general framework, based on the Husimi distribution function, for the calculation of entropy growth in quantum field theories, which is applicable to the earliest ('glasma') phase of the collision during which most of the entropy is generated. The entropy calculated from the Husimi distribution exhibits linear growth when the quantum field contains unstable modes and is asymptotically equal to the Kolmogorov-Sinai (KS) entropy. We outline how the approach can be used to investigate the problem of entropy production in a relativistic heavy-ion reaction from first principles.
Entropy production and thermodynamics of nonequilibrium stationary states: a point of view.
Gallavotti, Giovanni
2004-09-01
Entropy might be a not well defined concept if the system can undergo transformations involving stationary nonequilibria. It might be analogous to the heat content (once called "caloric") in transformations that are not isochoric (i.e., which involve mechanical work): it could be just a quantity that can be transferred or created, like heat in equilibrium. The text first reviews the philosophy behind a recently proposed definition of entropy production in nonequilibrium stationary systems. A detailed technical attempt at defining the entropy of a stationary states via their variational properties follows: the unsatisfactory aspects of the results add arguments in favor of the nonexistence of a function of state to be identified with entropy; at the same time new aspects and properties of the phase space contraction emerge. Copyright 2004 American Institute of Physics
International Nuclear Information System (INIS)
2016-01-01
Jung is responding to the challenge of energy efficiency, ease of operation and economic profitability in all of its solutions for the tertiary sector, whether for newly constructed buildings or refurbishments, for full management of the electrical system or the partial control of lighting, HVAC, mood settings, access control, etc., for the bedrooms or specific areas of the building. In the specific case of hotels, Jung offers each a custom-made solution in line with its possibilities and objectives. (Author)
Directory of Open Access Journals (Sweden)
J. J. Vallino
2011-06-01
Full Text Available In this manuscript we investigate the use of the maximum entropy production (MEP principle for modeling biogeochemical processes that are catalyzed by living systems. Because of novelties introduced by the MEP approach, many questions need to be answered and techniques developed in the application of MEP to describe biological systems that are responsible for energy and mass transformations on a planetary scale. In previous work we introduce the importance of integrating entropy production over time to distinguish abiotic from biotic processes under transient conditions. Here we investigate the ramifications of modeling biological systems involving one or more spatial dimensions. When modeling systems over space, entropy production can be maximized either locally at each point in space asynchronously or globally over the system domain synchronously. We use a simple two-box model inspired by two-layer ocean models to illustrate the differences in local versus global entropy maximization. Synthesis and oxidation of biological structure is modeled using two autocatalytic reactions that account for changes in community kinetics using a single parameter each. Our results show that entropy production can be increased if maximized over the system domain rather than locally, which has important implications regarding how biological systems organize and supports the hypothesis for multiple levels of selection and cooperation in biology for the dissipation of free energy.
Fluctuation theorem for entropy production during effusion of a relativistic ideal gas
CLEUREN, Bart; WILLAERT, Koen; ENGEL, Andreas; VAN DEN BROECK, Christian
2008-01-01
The probability distribution of the entropy production for the effusion of a relativistic ideal gas is calculated explicitly. This result is then extended to include particle and anti-particle pair production and annihilation. In both cases, the fluctuation theorem is verified.
Duan, Lili; Liu, Xiao; Zhang, John Z H
2016-05-04
Efficient and reliable calculation of protein-ligand binding free energy is a grand challenge in computational biology and is of critical importance in drug design and many other molecular recognition problems. The main challenge lies in the calculation of entropic contribution to protein-ligand binding or interaction systems. In this report, we present a new interaction entropy method which is theoretically rigorous, computationally efficient, and numerically reliable for calculating entropic contribution to free energy in protein-ligand binding and other interaction processes. Drastically different from the widely employed but extremely expensive normal mode method for calculating entropy change in protein-ligand binding, the new method calculates the entropic component (interaction entropy or -TΔS) of the binding free energy directly from molecular dynamics simulation without any extra computational cost. Extensive study of over a dozen randomly selected protein-ligand binding systems demonstrated that this interaction entropy method is both computationally efficient and numerically reliable and is vastly superior to the standard normal mode approach. This interaction entropy paradigm introduces a novel and intuitive conceptual understanding of the entropic effect in protein-ligand binding and other general interaction systems as well as a practical method for highly efficient calculation of this effect.
Entropy Production and the Pressure-Volume Curve of the Lung
Directory of Open Access Journals (Sweden)
Cláudio Lucas Oliveira
2016-03-01
Full Text Available We investigate analytically the production of entropy during a breathing cycle in healthy and diseased lungs. First, we calculate entropy production in healthy lungs by applying the laws of thermodynamics to the well-known transpulmonary pressure-volume (P-V curves of the lung under the assumption that lung tissue behaves as an entropy spring-like rubber. The bulk modulus, $B$, of the lung is also derived from these calculations. Second, we extend this approach to elastic recoil disorders of the lung such as occur in pulmonary fibrosis and emphysema. These diseases are characterized by particular alterations in the P-V relationship. For example, in fibrotic lungs B increases monotonically with disease progression, while in emphysema the opposite occurs. These diseases can thus be mimicked simply by making appropriate adjustments to the parameters of the P-V curve. Using Clausius's formalism, we show that entropy production, Delta_S, is related to the hysteresis area, Delta_A, enclosed by the P-V curve during a breathing cycle, namely, Delta_S = Delta_A/T, where T is the body temperature. Although Delta_A is highly dependent on the disease, such formula applies to healthy as well as diseased lungs, regardless of the disease stage. Finally, we use ansatzs to predict analytically the entropy produced by the fibrotic and emphysematous lungs.
Entropy production by Q-ball decay for diluting long-lived charged particles
International Nuclear Information System (INIS)
Kasuya, S.
2007-09-01
The cosmic abundance of a long-lived charged particle such as a stau is tightly constrained by the catalyzed big bang nucleosynthesis. One of the ways to evade the constraints is to dilute those particles by a huge entropy production. We evaluate the dilution factor in a case that non-relativistic matter dominates the energy density of the universe and decays with large entropy production. We find that large Q balls can do the job, which is naturally produced in the gauge-mediated supersymmetry breaking scenario. (orig.)
CFT and Logarithmic Corrections to the Black Hole Entropy Product Formula
Directory of Open Access Journals (Sweden)
Parthapratim Pradhan
2017-01-01
Full Text Available We examine the logarithmic corrections to the black hole (BH entropy product formula of outer horizon and inner horizon by taking into account the effects of statistical quantum fluctuations around the thermal equilibrium and via conformal field theory (CFT. We argue that, in logarithmic corrections to the BH entropy product formula when calculated using CFT and taking into account the effects of quantum fluctuations around the thermal equilibrium, the formula should not be universal and it also should not be quantized. These results have been explicitly checked by giving several examples.
Normal Mode Analysis in Zeolites: Toward an Efficient Calculation of Adsorption Entropies.
De Moor, Bart A; Ghysels, An; Reyniers, Marie-Françoise; Van Speybroeck, Veronique; Waroquier, Michel; Marin, Guy B
2011-04-12
An efficient procedure for normal-mode analysis of extended systems, such as zeolites, is developed and illustrated for the physisorption and chemisorption of n-octane and isobutene in H-ZSM-22 and H-FAU using periodic DFT calculations employing the Vienna Ab Initio Simulation Package. Physisorption and chemisorption entropies resulting from partial Hessian vibrational analysis (PHVA) differ at most 10 J mol(-1) K(-1) from those resulting from full Hessian vibrational analysis, even for PHVA schemes in which only a very limited number of atoms are considered free. To acquire a well-conditioned Hessian, much tighter optimization criteria than commonly used for electronic energy calculations in zeolites are required, i.e., at least an energy cutoff of 400 eV, maximum force of 0.02 eV/Å, and self-consistent field loop convergence criteria of 10(-8) eV. For loosely bonded complexes the mobile adsorbate method is applied, in which frequency contributions originating from translational or rotational motions of the adsorbate are removed from the total partition function and replaced by free translational and/or rotational contributions. The frequencies corresponding with these translational and rotational modes can be selected unambiguously based on a mobile block Hessian-PHVA calculation, allowing the prediction of physisorption entropies within an accuracy of 10-15 J mol(-1) K(-1) as compared to experimental values. The approach presented in this study is useful for studies on other extended catalytic systems.
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, ...
Physical entropy, information entropy and their evolution equations
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Inspired by the evolution equation of nonequilibrium statistical physics entropy and the concise statistical formula of the entropy production rate, we develop a theory of the dynamic information entropy and build a nonlinear evolution equation of the information entropy density changing in time and state variable space. Its mathematical form and physical meaning are similar to the evolution equation of the physical entropy: The time rate of change of information entropy density originates together from drift, diffusion and production. The concise statistical formula of information entropy production rate is similar to that of physical entropy also. Furthermore, we study the similarity and difference between physical entropy and information entropy and the possible unification of the two statistical entropies, and discuss the relationship among the principle of entropy increase, the principle of equilibrium maximum entropy and the principle of maximum information entropy as well as the connection between them and the entropy evolution equation.
On the validity of entropy production principles for linear electrical circuits
Czech Academy of Sciences Publication Activity Database
Bruers, S.; Maes, C.; Netočný, Karel
2007-01-01
Roč. 129, - (2007), s. 725-740 ISSN 0022-4715 R&D Projects: GA ČR GA202/07/0404 Institutional research plan: CEZ:AV0Z10100520 Keywords : entropy production * variational principles * nonequilibrium fluctuations Subject RIV: BE - Theoretical Physics Impact factor: 1.605, year: 2007
International Nuclear Information System (INIS)
Sun Fengrui; Qin Xiaoyong; Chen Lingen; Wu Chih
2005-01-01
For an endoreversible four-heat-reservoir absorption heat-transformer cycle, for which a linear (Newtonian) heat-transfer law applies, an ecological optimization criterion is proposed for the best mode of operation of the cycle. This involves maximizing a function representing the compromise between the heating load and the entropy-production rate. The optimal relation between the ecological criterion and the COP (coefficient of performance), the maximum ecological criterion and the corresponding COP, heating load and entropy production rate, as well as the ecological criterion and entropy-production rate at the maximum heating load are derived using finite-time thermodynamics. Moreover, compared with the heating-load criterion, the effects of the cycle parameters on the ecological performance are studied by numerical examples. These show that achieving the maximum ecological criterion makes the entropy-production rate decrease by 77.0% and the COP increase by 55.4% with only 27.3% heating-load losses compared with the maximum heating-load objective. The results reflect that the ecological criterion has long-term significance for optimal design of absorption heat-transformers
Zunino, Luciano; Bariviera, Aurelio F.; Guercio, M. Belén; Martinez, Lisana B.; Rosso, Osvaldo A.
2016-08-01
In this paper the permutation min-entropy has been implemented to unveil the presence of temporal structures in the daily values of European corporate bond indices from April 2001 to August 2015. More precisely, the informational efficiency evolution of the prices of fifteen sectorial indices has been carefully studied by estimating this information-theory-derived symbolic tool over a sliding time window. Such a dynamical analysis makes possible to obtain relevant conclusions about the effect that the 2008 credit crisis has had on the different European corporate bond sectors. It is found that the informational efficiency of some sectors, namely banks, financial services, insurance, and basic resources, has been strongly reduced due to the financial crisis whereas another set of sectors, integrated by chemicals, automobiles, media, energy, construction, industrial goods & services, technology, and telecommunications has only suffered a transitory loss of efficiency. Last but not least, the food & beverage, healthcare, and utilities sectors show a behavior close to a random walk practically along all the period of analysis, confirming a remarkable immunity against the 2008 financial crisis.
Expansion, thermalization, and entropy production in high-energy nuclear collisions
International Nuclear Information System (INIS)
Heiselberg, H.; Wang, X.
1996-01-01
The thermalization process is studied in an expanding parton gas using the Boltzmann equation with two types of collision terms. In the relaxation time approximation we determine the criteria under which a time-dependent relaxation time leads to thermalization of the partons. We calculate the entropy production due to collisions for the general time-dependent relaxation time. In a perturbative QCD approach on the other hand, we can, given the initial conditions, estimate the effective relaxation time due to elastic collisions; this will be an upper limit only since radiative processes will also contribute to thermalization. We find that the parton gas does thermalize eventually but only after having undergone a phase of free streaming and gradual equilibration where considerable entropy is produced (open-quote open-quote after burning close-quote close-quote). The final entropy and thus particle density depends on the collision time as well as the initial conditions (a open-quote open-quote memory effect close-quote close-quote). Results for entropy production are presented based upon various model estimates of early parton production. copyright 1996 The American Physical Society
Minimizing the entropy production in a chemical process for dehydrogenation of propane
International Nuclear Information System (INIS)
Rosjorde, A.; Kjelstrup, S.; Johannessen, E.; Hansen, R.
2007-01-01
We minimize the total entropy production of a process designed for dehydrogenation of propane. The process consists of 21 units, including a plug-flow reactor, a partial condenser, two tray distillation columns and a handful of heat exchangers and compressors. The units were modeled in a manner that made them relatively insensitive to changes in the molar flow rates, to make the optimization more flexible. The operating conditions, as well as to some degree the design of selected units, which minimized the total entropy production of the process, were found. The most important variables were the amount of recycled propane and propylene, conversion and selectivity in the reactor, as well as the number of tubes in the reactor. The optimal conversion, selectivity and recycle flows were results of a very clear trade-off among the entropy produced in the reactor, the partial condenser and the two distillation columns. Although several simplifying assumptions were made for computational reasons, this shows for the first time that it is also meaningful to use the entropy production as an objective function in chemical engineering process optimization studies
Efficient Computation of Entropy Gradient for Semi-Supervised Conditional Random Fields
National Research Council Canada - National Science Library
Mann, Gideon S; McCallum, Andrew
2007-01-01
Entropy regularization is a straightforward and successful method of semi-supervised learning that augments the traditional conditional likelihood objective function with an additional term that aims...
Kleidon, Axel
2009-06-01
The Earth system is maintained in a unique state far from thermodynamic equilibrium, as, for instance, reflected in the high concentration of reactive oxygen in the atmosphere. The myriad of processes that transform energy, that result in the motion of mass in the atmosphere, in oceans, and on land, processes that drive the global water, carbon, and other biogeochemical cycles, all have in common that they are irreversible in their nature. Entropy production is a general consequence of these processes and measures their degree of irreversibility. The proposed principle of maximum entropy production (MEP) states that systems are driven to steady states in which they produce entropy at the maximum possible rate given the prevailing constraints. In this review, the basics of nonequilibrium thermodynamics are described, as well as how these apply to Earth system processes. Applications of the MEP principle are discussed, ranging from the strength of the atmospheric circulation, the hydrological cycle, and biogeochemical cycles to the role that life plays in these processes. Nonequilibrium thermodynamics and the MEP principle have potentially wide-ranging implications for our understanding of Earth system functioning, how it has evolved in the past, and why it is habitable. Entropy production allows us to quantify an objective direction of Earth system change (closer to vs further away from thermodynamic equilibrium, or, equivalently, towards a state of MEP). When a maximum in entropy production is reached, MEP implies that the Earth system reacts to perturbations primarily with negative feedbacks. In conclusion, this nonequilibrium thermodynamic view of the Earth system shows great promise to establish a holistic description of the Earth as one system. This perspective is likely to allow us to better understand and predict its function as one entity, how it has evolved in the past, and how it is modified by human activities in the future.
Entropy production and multiple equilibria: the case of the ice-albedo feedback
Directory of Open Access Journals (Sweden)
C. Herbert
2011-02-01
Full Text Available Nonlinear feedbacks in the Earth System provide mechanisms that can prove very useful in understanding complex dynamics with relatively simple concepts. For example, the temperature and the ice cover of the planet are linked in a positive feedback which gives birth to multiple equilibria for some values of the solar constant: fully ice-covered Earth, ice-free Earth and an intermediate unstable solution. In this study, we show an analogy between a classical dynamical system approach to this problem and a Maximum Entropy Production (MEP principle view, and we suggest a glimpse on how to reconcile MEP with the time evolution of a variable. It enables us in particular to resolve the question of the stability of the entropy production maxima. We also compare the surface heat flux obtained with MEP and with the bulk-aerodynamic formula.
Comments on a derivation and application of the 'maximum entropy production' principle
International Nuclear Information System (INIS)
Grinstein, G; Linsker, R
2007-01-01
We show that (1) an error invalidates the derivation (Dewar 2005 J. Phys. A: Math. Gen. 38 L371) of the maximum entropy production (MaxEP) principle for systems far from equilibrium, for which the constitutive relations are nonlinear; and (2) the claim (Dewar 2003 J. Phys. A: Math. Gen. 36 631) that the phenomenon of 'self-organized criticality' is a consequence of MaxEP for slowly driven systems is unjustified. (comment)
Fluctuation theorem for entropy production during effusion of an ideal gas with momentum transfer.
Wood, Kevin; Van den Broeck, C; Kawai, R; Lindenberg, Katja
2007-06-01
We derive an exact expression for entropy production during effusion of an ideal gas driven by momentum transfer in addition to energy and particle flux. Following the treatment in Cleuren [Phys. Rev. E 74, 021117 (2006)], we construct a master equation formulation of the process and explicitly verify the thermodynamic fluctuation theorem, thereby directly exhibiting its extended applicability to particle flows and hence to hydrodynamic systems.
International Nuclear Information System (INIS)
Dobbertin, R.
1976-01-01
Functional relations are derived which link the reduced distribution functions of a classical N-particle system through the entropy production due to microscopic deviations from hamiltonian dynamics. These relations have been used in an earlier paper for the closure of the BBGKY-hierarchy and may be useful for the establishment of collective particle models in particular and the understanding of irreversibility in general. (Auth.)
Non-equilibrium Thermodynamics and the Production of Entropy Life, Earth, and Beyond
Kleidon, Axel
2005-01-01
The present volume studies the application of concepts from non-equilibrium thermodynamics to a variety of research topics. Emphasis is on the Maximum Entropy Production (MEP) principle and applications to Geosphere-Biosphere couplings. Written by leading researchers form a wide range of background, the book proposed to give a first coherent account of an emerging field at the interface of thermodynamics, geophysics and life sciences.
Energy consumption and entropy production in a stochastic formulation of BCM learning
International Nuclear Information System (INIS)
De Oliveira, L R; Castellani, G; Turchetti, G
2013-01-01
Biochemical processes in living cells are open systems, therefore they exchange materials with their environment and they consume chemical energy. These processes are molecular-based and for that reason the role of fluctuations can not be ignored and the stochastic description is the most appropriate one. The chemical master equation describes in exact way the probabilistic dynamics of a given discrete set of states and helps us to understand and clarify the differences between closed and open systems. A closed system is related to a condition of detailed balance (DB), i.e. an equilibrium state. After a sufficiently long period, an open system will reach a non-equilibrium steady state (NESS) that is sustained by a flux of external energy. We demonstrate that two implementations of the BCM learning rule (BCM82) and (BCM92) are, respectively, always in DB, and never in DB. We define a one parameter parametrization of the BCM learning rule that interpolates between these two extremes. We compute thermodynamical quantities such as internal energy, free energy (both Helmholtz and Gibbs) and entropy. The entropy variation in the case of open systems (i.e. when DB does not hold) can be divided into internal entropy production and entropy exchanged with surroundings. We show how the entropy variation can be used to find the optimal value (corresponding to increased robustness and stability) for the parameter used in the BCM parametrization. Finally, we use the calculation of the work to drive the system from an initial state to the steady state as the parameter of the plasticity of the system
On extremals of the entropy production by ‘Langevin–Kramers’ dynamics
International Nuclear Information System (INIS)
Muratore-Ginanneschi, Paolo
2014-01-01
We refer as ‘Langevin–Kramers’ dynamics to a class of stochastic differential systems exhibiting a degenerate ‘metriplectic’ structure. This means that the drift field can be decomposed into a symplectic and a gradient-like component with respect to a pseudo-metric tensor associated with random fluctuations affecting increments of only a sub-set of the degrees of freedom. Systems in this class are often encountered in applications as elementary models of Hamiltonian dynamics in a heat bath eventually relaxing to a Boltzmann steady state. Entropy production control in Langevin–Kramers models differs from the now well-understood case of Langevin–Smoluchowski dynamics for two reasons. First, the definition of entropy production stemming from fluctuation theorems specifies a cost functional which does not act coercively on all degrees of freedom of control protocols. Second, the presence of a symplectic structure imposes a non-local constraint on the class of admissible controls. Using Pontryagin control theory and restricting the attention to additive noise, we show that smooth protocols attaining extremal values of the entropy production appear generically in continuous parametric families as a consequence of a trade-off between smoothness of the admissible protocols and non-coercivity of the cost functional. Uniqueness is, however, always recovered in the over-damped limit as extremal equations reduce at leading order to the Monge–Ampère–Kantorovich optimal mass-transport equations. (paper)
Directory of Open Access Journals (Sweden)
Brohi Ali Anwar
2017-01-01
Full Text Available The entropy production in 2-D heat transfer system has been analyzed systematically by using the finite volume method, to develop new criteria for the numerical simulation in case of multidimensional systems, with the aid of the CFD codes. The steady-state heat conduction problem has been investigated for entropy production, and the entropy production profile has been calculated based upon the current approach. From results for 2-D heat conduction, it can be found that the stability of entropy production profile exhibits a better agreement with the exact solution accordingly, and the current approach is effective for measuring the accuracy and stability of numerical simulations for heat transfer problems.
Bellan, J.; Okongo, N.
2000-01-01
A study of emerging turbulent scales entropy production is conducted for a supercritical shear layer as a precursor to the eventual modeling of Subgrid Scales (from a turbulent state) leading to Large Eddy Simulations.
Directory of Open Access Journals (Sweden)
S. Pascale
2012-01-01
Full Text Available The objective of this paper is to reconsider the Maximum Entropy Production conjecture (MEP in the context of a very simple two-dimensional zonal-vertical climate model able to represent the total material entropy production due at the same time to both horizontal and vertical heat fluxes. MEP is applied first to a simple four-box model of climate which accounts for both horizontal and vertical material heat fluxes. It is shown that, under condition of fixed insolation, a MEP solution is found with reasonably realistic temperature and heat fluxes, thus generalising results from independent two-box horizontal or vertical models. It is also shown that the meridional and the vertical entropy production terms are independently involved in the maximisation and thus MEP can be applied to each subsystem with fixed boundary conditions. We then extend the four-box model by increasing its resolution, and compare it with GCM output. A MEP solution is found which is fairly realistic as far as the horizontal large scale organisation of the climate is concerned whereas the vertical structure looks to be unrealistic and presents seriously unstable features. This study suggest that the thermal meridional structure of the atmosphere is predicted fairly well by MEP once the insolation is given but the vertical structure of the atmosphere cannot be predicted satisfactorily by MEP unless constraints are imposed to represent the determination of longwave absorption by water vapour and clouds as a function of the state of the climate. Furthermore an order-of-magnitude estimate of contributions to the material entropy production due to horizontal and vertical processes within the climate system is provided by using two different methods. In both cases we found that approximately 40 mW m^{−2} K^{−1} of material entropy production is due to vertical heat transport and 5–7 mW m^{−2} K^{−1} to horizontal heat transport.
Maximum Entropy Production Is Not a Steady State Attractor for 2D Fluid Convection
Directory of Open Access Journals (Sweden)
Stuart Bartlett
2016-12-01
Full Text Available Multiple authors have claimed that the natural convection of a fluid is a process that exhibits maximum entropy production (MEP. However, almost all such investigations were limited to fixed temperature boundary conditions (BCs. It was found that under those conditions, the system tends to maximize its heat flux, and hence it was concluded that the MEP state is a dynamical attractor. However, since entropy production varies with heat flux and difference of inverse temperature, it is essential that any complete investigation of entropy production allows for variations in heat flux and temperature difference. Only then can we legitimately assess whether the MEP state is the most attractive. Our previous work made use of negative feedback BCs to explore this possibility. We found that the steady state of the system was far from the MEP state. For any system, entropy production can only be maximized subject to a finite set of physical and material constraints. In the case of our previous work, it was possible that the adopted set of fluid parameters were constraining the system in such a way that it was entirely prevented from reaching the MEP state. Hence, in the present work, we used a different set of boundary parameters, such that the steady states of the system were in the local vicinity of the MEP state. If MEP was indeed an attractor, relaxing those constraints of our previous work should have caused a discrete perturbation to the surface of steady state heat flux values near the value corresponding to MEP. We found no such perturbation, and hence no discernible attraction to the MEP state. Furthermore, systems with fixed flux BCs actually minimize their entropy production (relative to the alternative stable state, that of pure diffusive heat transport. This leads us to conclude that the principle of MEP is not an accurate indicator of which stable steady state a convective system will adopt. However, for all BCs considered, the quotient of
Entropy production rate as a criterion for inconsistency in decision theory
Dixit, Purushottam D.
2018-05-01
Individual and group decisions are complex, often involving choosing an apt alternative from a multitude of options. Evaluating pairwise comparisons breaks down such complex decision problems into tractable ones. Pairwise comparison matrices (PCMs) are regularly used to solve multiple-criteria decision-making problems, for example, using Saaty’s analytic hierarchy process (AHP) framework. However, there are two significant drawbacks of using PCMs. First, humans evaluate PCMs in an inconsistent manner. Second, not all entries of a large PCM can be reliably filled by human decision makers. We address these two issues by first establishing a novel connection between PCMs and time-irreversible Markov processes. Specifically, we show that every PCM induces a family of dissipative maximum path entropy random walks (MERW) over the set of alternatives. We show that only ‘consistent’ PCMs correspond to detailed balanced MERWs. We identify the non-equilibrium entropy production in the induced MERWs as a metric of inconsistency of the underlying PCMs. Notably, the entropy production satisfies all of the recently laid out criteria for reasonable consistency indices. We also propose an approach to use incompletely filled PCMs in AHP. Potential future avenues are discussed as well.
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.
Minimum entropy production closure of the photo-hydrodynamic equations for radiative heat transfer
International Nuclear Information System (INIS)
Christen, Thomas; Kassubek, Frank
2009-01-01
In the framework of a two-moment photo-hydrodynamic modelling of radiation transport, we introduce a concept for the determination of effective radiation transport coefficients based on the minimization of the local entropy production rate of radiation and (generally nongrey) matter. The method provides the nonequilibrium photon distribution from which the effective (variable) absorption coefficients and the variable Eddington factor (VEF) can be calculated. For a single band model, the photon distribution depends explicitly on the frequency dependence of the absorption coefficient. Without introducing artificial fit parameters, multi-group or multi-band concepts, our approach reproduces the exact results in both limits of optically thick (Rosseland mean) and optically thin (Planck mean) media, in contrast to the maximum entropy method. Also the results for general nonequilibrium radiation between the limits of diffusive and ballistic photons are reasonable. We conjecture that the reason for the success of our approach lies in the linearity of the underlying Boltzmann equation of the photon gas. The method is illustrated and discussed for grey matter and for a simple example of nongrey matter with a two-band absorption spectrum. The method is also briefly compared with the maximum entropy concept.
Energy Technology Data Exchange (ETDEWEB)
Santos, Marcio Bueno dos [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Lab. de Integracao e Testes; Saboya, Sergio Mourao [Instituto Tecnologico de Aeronautica, Sao Jose dos Campos, SP (Brazil). Dept. de Energia
1998-07-01
This paper studies the efficiency of a fined tube solar collector used in artificial satellites and the relation of this efficiency with the entropy generation in the fin. The mathematical modeling of heat transfer in the collector leads to a non-linear integrodifferential system of equations, which is solved numerically. The solution gives the efficiency, which is presented as function of geometrical and physical characteristics of the collector. It is also shown that a minimum entropy generation in the fins, in a collector, whose characteristics are subjected to constraints, corresponds to an optimum efficiency, that is, an efficiency value advantageous to collector performance. (author)
Directory of Open Access Journals (Sweden)
Axel Kleidon
2010-03-01
Full Text Available The Maximum Entropy Production (MEP principle has been remarkably successful in producing accurate predictions for non-equilibrium states. We argue that this is because the MEP principle is an effective inference procedure that produces the best predictions from the available information. Since all Earth system processes are subject to the conservation of energy, mass and momentum, we argue that in practical terms the MEP principle should be applied to Earth system processes in terms of the already established framework of non-equilibrium thermodynamics, with the assumption of local thermodynamic equilibrium at the appropriate scales.
Directory of Open Access Journals (Sweden)
Florian Ries
2017-08-01
Full Text Available In the present paper, thermal transport and entropy production mechanisms in a turbulent round jet of compressed nitrogen at supercritical thermodynamic conditions are investigated using a direct numerical simulation. First, thermal transport and its contribution to the mixture formation along with the anisotropy of heat fluxes and temperature scales are examined. Secondly, the entropy production rates during thermofluid processes evolving in the supercritical flow are investigated in order to identify the causes of irreversibilities and to display advantageous locations of handling along with the process regimes favorable to mixing. Thereby, it turned out that (1 the jet disintegration process consists of four main stages under supercritical conditions (potential core, separation, pseudo-boiling, turbulent mixing, (2 causes of irreversibilities are primarily due to heat transport and thermodynamic effects rather than turbulence dynamics and (3 heat fluxes and temperature scales appear anisotropic even at the smallest scales, which implies that anisotropic thermal diffusivity models might be appropriate in the context of both Reynolds-averaged Navier–Stokes (RANS and large eddy simulation (LES approaches while numerically modeling supercritical fluid flows.
Directory of Open Access Journals (Sweden)
Xiong Luo
2016-07-01
Full Text Available With the recent emergence of wireless sensor networks (WSNs in the cloud computing environment, it is now possible to monitor and gather physical information via lots of sensor nodes to meet the requirements of cloud services. Generally, those sensor nodes collect data and send data to sink node where end-users can query all the information and achieve cloud applications. Currently, one of the main disadvantages in the sensor nodes is that they are with limited physical performance relating to less memory for storage and less source of power. Therefore, in order to avoid such limitation, it is necessary to develop an efficient data prediction method in WSN. To serve this purpose, by reducing the redundant data transmission between sensor nodes and sink node while maintaining the required acceptable errors, this article proposes an entropy-based learning scheme for data prediction through the use of kernel least mean square (KLMS algorithm. The proposed scheme called E-KLMS develops a mechanism to maintain the predicted data synchronous at both sides. Specifically, the kernel-based method is able to adjust the coefficients adaptively in accordance with every input, which will achieve a better performance with smaller prediction errors, while employing information entropy to remove these data which may cause relatively large errors. E-KLMS can effectively solve the tradeoff problem between prediction accuracy and computational efforts while greatly simplifying the training structure compared with some other data prediction approaches. What’s more, the kernel-based method and entropy technique could ensure the prediction effect by both improving the accuracy and reducing errors. Experiments with some real data sets have been carried out to validate the efficiency and effectiveness of E-KLMS learning scheme, and the experiment results show advantages of the our method in prediction accuracy and computational time.
International Nuclear Information System (INIS)
Ojima, Izumi
1989-01-01
With aid of the so-called dilation method, a concise formula is obtained for the entropy production in the algebraic formulation of quantum dynamical systems. In this framework, the initial ergodic state of an external force system plays a pivotal role in generating dissipativity as a conditional expectation. The physical meaning of van Hove limit is clarified through the scale-changing transformation to control transitions between microscopic and macroscopic levels. It plays a crucial role in realizing the macroscopic stationary in the presence of microscopic fluctuations as well as in the transition from non-Markovian (groupoid) dynamics to Markovian dissipative processes of state changes. The extension of the formalism to cases with spatial and internal inhomogeneity is indicated in the light of the groupoid dynamical systems and noncommutative integration theory
The Efficiency of Educational Production
DEFF Research Database (Denmark)
Bogetoft, Peter; Heinesen, Eskil; Tranæs, Torben
is the most efficient Nordic country (often fully efficient), whereas Sweden and especially Norway and Denmark are clearly inefficient. However, using PISA test scores as indicators of student input quality in upper secondary education reduces the inefficiencies of these three countries. Also, when expected......Focusing in particular on upper secondary education, this paper examines whether the relatively high level of expenditure on education in the Nordic countries is matched by high output from the educational sector, both in terms of student enrolment and indicators of output quality in the form...... of graduation/completion rates and expected earnings after completed education. We use Data Envelopment Analysis (DEA) to compare (benchmark) the Nordic countries with a relevant group of rich OECD countries and calculate input efficiency scores for each country. We estimate a wide range of specifications...
The Efficiency of Educational Production
DEFF Research Database (Denmark)
Bogetoft, Peter; Heinesen, Eskil; Tranæs, Torben
2015-01-01
is the most efficient Nordic country (often fully efficient), whereas Sweden and especially Norway and Denmark are clearly inefficient. However, using PISA test scores as indicators of student input quality in upper secondary education reduces the inefficiencies of these three countries. Also, when expected......Focusing in particular on upper secondary education, this paper examines whether the relatively high level of expenditure on education in the Nordic countries is matched by high output from the educational sector, both in terms of student enrolment and indicators of output quality in the form...... of graduation/completion rates and expected earnings after completed education. We use data envelopment analysis (DEA) to compare (benchmark) the Nordic countries with a relevant group of rich OECD countries and calculate input efficiency scores for each country. We estimate a wide range of specifications...
BOREAS TE-17 Production Efficiency Model Images
National Aeronautics and Space Administration — A BOREAS version of the Global Production Efficiency Model(www.inform.umd.edu/glopem) was developed by TE-17 to generate maps of gross and net primary production,...
Non-equilibrium thermodynamics, maximum entropy production and Earth-system evolution.
Kleidon, Axel
2010-01-13
The present-day atmosphere is in a unique state far from thermodynamic equilibrium. This uniqueness is for instance reflected in the high concentration of molecular oxygen and the low relative humidity in the atmosphere. Given that the concentration of atmospheric oxygen has likely increased throughout Earth-system history, we can ask whether this trend can be generalized to a trend of Earth-system evolution that is directed away from thermodynamic equilibrium, why we would expect such a trend to take place and what it would imply for Earth-system evolution as a whole. The justification for such a trend could be found in the proposed general principle of maximum entropy production (MEP), which states that non-equilibrium thermodynamic systems maintain steady states at which entropy production is maximized. Here, I justify and demonstrate this application of MEP to the Earth at the planetary scale. I first describe the non-equilibrium thermodynamic nature of Earth-system processes and distinguish processes that drive the system's state away from equilibrium from those that are directed towards equilibrium. I formulate the interactions among these processes from a thermodynamic perspective and then connect them to a holistic view of the planetary thermodynamic state of the Earth system. In conclusion, non-equilibrium thermodynamics and MEP have the potential to provide a simple and holistic theory of Earth-system functioning. This theory can be used to derive overall evolutionary trends of the Earth's past, identify the role that life plays in driving thermodynamic states far from equilibrium, identify habitability in other planetary environments and evaluate human impacts on Earth-system functioning. This journal is © 2010 The Royal Society
Energy production and reactor efficiency
International Nuclear Information System (INIS)
Anon.
1975-01-01
Doubts have been raised in relation to the economic and energetic efficiency of nuclear reactors. Some economists are questioning whether, when all the capital and material inputs to fission technology are considered, nuclear reactors yield sufficiently large amounts of energy to show a nett gain of energy. (author)
The Efficiency of Educational Production
DEFF Research Database (Denmark)
Bogetoft, Peter; Heinesen, Eskil; Tranæs, Torben
the educational sector, both in terms of a large number of students enrolled in educational programmes and a high completion rate. The methodology used is to compare (benchmark) Denmark with a relevant group of countries and to calculate how much cheaper Denmark could teach the same number of students...... to explain the higher costs of upper secondary education. On the output side, if earnings and levels of employment among those who complete their education are taken into account, then Denmark is in fact found to be efficient. However, this high level of efficiency has become less clear-cut in recent years......Denmark, Norway, New Zealand, Canada and the USA are the OECD countries that spend most on education, measured in relation to GDP. Focusing in particular on upper secondary education, this paper examines whether the heavy expenditure on education in Denmark is matched by high output from...
Eco-efficiency in industrial production
von Raesfeld Meijer, Ariane M.; de Bakker, F.G.A.; Groen, Arend J.
2001-01-01
English AbstractThis report of the MATRIC project investigated 'Eco-efficiency in industrial production'. After a general introduction into the domain of eco-efficiency, the first part of this report further focusses on the organisation of Product-Oriented Environmental Management (POEM), which is
Chemistry - Toward efficient hydrogen production at surfaces
DEFF Research Database (Denmark)
Nørskov, Jens Kehlet; Christensen, Claus H.
2006-01-01
Calculations are providing a molecular picture of hydrogen production on catalytic surfaces and within enzymes, knowledge that may guide the design of new, more efficient catalysts for the hydrogen economy.......Calculations are providing a molecular picture of hydrogen production on catalytic surfaces and within enzymes, knowledge that may guide the design of new, more efficient catalysts for the hydrogen economy....
DeVore, Matthew S; Gull, Stephen F; Johnson, Carey K
2012-04-05
We describe a method for analysis of single-molecule Förster resonance energy transfer (FRET) burst measurements using classic maximum entropy. Classic maximum entropy determines the Bayesian inference for the joint probability describing the total fluorescence photons and the apparent FRET efficiency. The method was tested with simulated data and then with DNA labeled with fluorescent dyes. The most probable joint distribution can be marginalized to obtain both the overall distribution of fluorescence photons and the apparent FRET efficiency distribution. This method proves to be ideal for determining the distance distribution of FRET-labeled biomolecules, and it successfully predicts the shape of the recovered distributions.
Improving efficiency in pig production
African Journals Online (AJOL)
by adopting different strategies for meat production ... lates to some specific nutritional considerations. ... allowances were made for the correlated effects of any change. ... end of her reproductive life the sow is also usually sold for meat ... the experimental work. ... on pigs of up-to-date genotype fed on modern balanced diets.
Xu, Jun; Dang, Chao; Kong, Fan
2017-10-01
This paper presents a new method for efficient structural reliability analysis. In this method, a rotational quasi-symmetric point method (RQ-SPM) is proposed for evaluating the fractional moments of the performance function. Then, the derivation of the performance function's probability density function (PDF) is carried out based on the maximum entropy method in which constraints are specified in terms of fractional moments. In this regard, the probability of failure can be obtained by a simple integral over the performance function's PDF. Six examples, including a finite element-based reliability analysis and a dynamic system with strong nonlinearity, are used to illustrate the efficacy of the proposed method. All the computed results are compared with those by Monte Carlo simulation (MCS). It is found that the proposed method can provide very accurate results with low computational effort.
Tang, Qingxin; Bo, Yanchen; Zhu, Yuxin
2016-04-01
Merging multisensor aerosol optical depth (AOD) products is an effective way to produce more spatiotemporally complete and accurate AOD products. A spatiotemporal statistical data fusion framework based on a Bayesian maximum entropy (BME) method was developed for merging satellite AOD products in East Asia. The advantages of the presented merging framework are that it not only utilizes the spatiotemporal autocorrelations but also explicitly incorporates the uncertainties of the AOD products being merged. The satellite AOD products used for merging are the Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 5.1 Level-2 AOD products (MOD04_L2) and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Deep Blue Level 2 AOD products (SWDB_L2). The results show that the average completeness of the merged AOD data is 95.2%,which is significantly superior to the completeness of MOD04_L2 (22.9%) and SWDB_L2 (20.2%). By comparing the merged AOD to the Aerosol Robotic Network AOD records, the results show that the correlation coefficient (0.75), root-mean-square error (0.29), and mean bias (0.068) of the merged AOD are close to those (the correlation coefficient (0.82), root-mean-square error (0.19), and mean bias (0.059)) of the MODIS AOD. In the regions where both MODIS and SeaWiFS have valid observations, the accuracy of the merged AOD is higher than those of MODIS and SeaWiFS AODs. Even in regions where both MODIS and SeaWiFS AODs are missing, the accuracy of the merged AOD is also close to the accuracy of the regions where both MODIS and SeaWiFS have valid observations.
International Nuclear Information System (INIS)
Bian Yiwen; Yang Feng
2010-01-01
Data envelopment analysis (DEA) has been widely used in energy efficiency and environment efficiency analysis in recent years. Based on the existing environment DEA technology, this paper presents several DEA models for estimating the aggregated efficiency of resource and environment. These models can evaluate DMUs' energy efficiencies and environment efficiencies simultaneously. However, efficiency ranking results obtained from these models are not the same, and each model can provide some valuable information of DMUs' efficiencies, which we could not ignore. Under this situation, it may be hard for us to choose a specific model in practice. To address this kind of performance evaluation problem, the current paper extends Shannon-DEA procedure to establish a comprehensive efficiency measure for appraising DMUs' resource and environment efficiencies. In the proposed approach, the measure for evaluating a model's importance degree is provided, and the targets setting approach of inputs/outputs for DMU managers to improve DMUs' energy and environmental efficiencies is also discussed. We illustrate the proposed approach using real data set of 30 provinces in China.
Ownership and efficiency in nuclear power production
International Nuclear Information System (INIS)
Pollitt, M.G.
1995-01-01
This paper aims to contribute to the relatively small amount of academic literature on the efficiency of nuclear power production. The author draws on world-wide comparisons to illustrate the situation in the United Kingdom, where the nuclear generating capacity, conceived of and constructed as a public concern, has recently been privatised. The theory and evidence for links between ownership and productive efficiency is received. Efficiency measures used are explained as are the linear programs required to generate them. Data Envelopment Analysis (DEA) is used to analyse productive efficiency of nuclear power plants before and after privatisation. Results of the DEA are used to test the hypothesis that ownership has no effect on productive efficiency. (UK)
Quantum chaos: entropy signatures
International Nuclear Information System (INIS)
Miller, P.A.; Sarkar, S.; Zarum, R.
1998-01-01
A definition of quantum chaos is given in terms of entropy production rates for a quantum system coupled weakly to a reservoir. This allows the treatment of classical and quantum chaos on the same footing. In the quantum theory the entropy considered is the von Neumann entropy and in classical systems it is the Gibbs entropy. The rate of change of the coarse-grained Gibbs entropy of the classical system with time is given by the Kolmogorov-Sinai (KS) entropy. The relation between KS entropy and the rate of change of von Neumann entropy is investigated for the kicked rotator. For a system which is classically chaotic there is a linear relationship between these two entropies. Moreover it is possible to construct contour plots for the local KS entropy and compare it with the corresponding plots for the rate of change of von Neumann entropy. The quantitative and qualitative similarities of these plots are discussed for the standard map (kicked rotor) and the generalised cat maps. (author)
RNA Thermodynamic Structural Entropy.
Garcia-Martin, Juan Antonio; Clote, Peter
2015-01-01
Conformational entropy for atomic-level, three dimensional biomolecules is known experimentally to play an important role in protein-ligand discrimination, yet reliable computation of entropy remains a difficult problem. Here we describe the first two accurate and efficient algorithms to compute the conformational entropy for RNA secondary structures, with respect to the Turner energy model, where free energy parameters are determined from UV absorption experiments. An algorithm to compute the derivational entropy for RNA secondary structures had previously been introduced, using stochastic context free grammars (SCFGs). However, the numerical value of derivational entropy depends heavily on the chosen context free grammar and on the training set used to estimate rule probabilities. Using data from the Rfam database, we determine that both of our thermodynamic methods, which agree in numerical value, are substantially faster than the SCFG method. Thermodynamic structural entropy is much smaller than derivational entropy, and the correlation between length-normalized thermodynamic entropy and derivational entropy is moderately weak to poor. In applications, we plot the structural entropy as a function of temperature for known thermoswitches, such as the repression of heat shock gene expression (ROSE) element, we determine that the correlation between hammerhead ribozyme cleavage activity and total free energy is improved by including an additional free energy term arising from conformational entropy, and we plot the structural entropy of windows of the HIV-1 genome. Our software RNAentropy can compute structural entropy for any user-specified temperature, and supports both the Turner'99 and Turner'04 energy parameters. It follows that RNAentropy is state-of-the-art software to compute RNA secondary structure conformational entropy. Source code is available at https://github.com/clotelab/RNAentropy/; a full web server is available at http
RNA Thermodynamic Structural Entropy.
Directory of Open Access Journals (Sweden)
Juan Antonio Garcia-Martin
Full Text Available Conformational entropy for atomic-level, three dimensional biomolecules is known experimentally to play an important role in protein-ligand discrimination, yet reliable computation of entropy remains a difficult problem. Here we describe the first two accurate and efficient algorithms to compute the conformational entropy for RNA secondary structures, with respect to the Turner energy model, where free energy parameters are determined from UV absorption experiments. An algorithm to compute the derivational entropy for RNA secondary structures had previously been introduced, using stochastic context free grammars (SCFGs. However, the numerical value of derivational entropy depends heavily on the chosen context free grammar and on the training set used to estimate rule probabilities. Using data from the Rfam database, we determine that both of our thermodynamic methods, which agree in numerical value, are substantially faster than the SCFG method. Thermodynamic structural entropy is much smaller than derivational entropy, and the correlation between length-normalized thermodynamic entropy and derivational entropy is moderately weak to poor. In applications, we plot the structural entropy as a function of temperature for known thermoswitches, such as the repression of heat shock gene expression (ROSE element, we determine that the correlation between hammerhead ribozyme cleavage activity and total free energy is improved by including an additional free energy term arising from conformational entropy, and we plot the structural entropy of windows of the HIV-1 genome. Our software RNAentropy can compute structural entropy for any user-specified temperature, and supports both the Turner'99 and Turner'04 energy parameters. It follows that RNAentropy is state-of-the-art software to compute RNA secondary structure conformational entropy. Source code is available at https://github.com/clotelab/RNAentropy/; a full web server is available at http
Cue Effectiveness in Communicatively Efficient Discourse Production
Qian, Ting; Jaeger, T. Florian
2012-01-01
Recent years have seen a surge in accounts motivated by information theory that consider language production to be partially driven by a preference for communicative efficiency. Evidence from discourse production (i.e., production beyond the sentence level) has been argued to suggest that speakers distribute information across discourse so as to…
Siokis, Fotios M.
2018-06-01
We explore the evolution of the informational efficiency for specific instruments of the U.S. money, bond and stock exchange markets, prior and after the outbreak of the Great Recession. We utilize the permutation entropy and the complexity-entropy causality plane to rank the time series and measure the degree of informational efficiency. We find that after the credit crunch and the collapse of Lehman Brothers the efficiency level of specific money market instruments' yield falls considerably. This is an evidence of less uncertainty included in predicting the related yields throughout the financial disarray. Similar trend is depicted in the indices of the stock exchange markets but efficiency remains in much higher levels. On the other hand, bond market instruments maintained their efficiency levels even after the outbreak of the crisis, which could be interpreted into greater randomness and less predictability of their yields.
International Nuclear Information System (INIS)
Kolb, E.W.; Lindley, D.; Seckel, D.
1984-01-01
For a cosmological model with d noncompact and D compact spatial dimensions and symmetry R 1 x S/sup d/ x S/sup D/, we calculate the entropy produced in d dimensions due to the compactification of D dimensions and show it too small to be of cosmological interest. Although insufficient entropy is produced in the model we study, the contraction of extra dimensions does lead to entropy production. We discuss modifications of our assumptions, including changing our condition for decoupling of the extra dimensions, which may lead to a large entropy production and change our conclusions
Bianchi, Eugenio; De Lorenzo, Tommaso; Smerlak, Matteo
2015-06-01
We study the dynamics of vacuum entanglement in the process of gravitational collapse and subsequent black hole evaporation. In the first part of the paper, we introduce a covariant regularization of entanglement entropy tailored to curved spacetimes; this regularization allows us to propose precise definitions for the concepts of black hole "exterior entropy" and "radiation entropy." For a Vaidya model of collapse we find results consistent with the standard thermodynamic properties of Hawking radiation. In the second part of the paper, we compute the vacuum entanglement entropy of various spherically-symmetric spacetimes of interest, including the nonsingular black hole model of Bardeen, Hayward, Frolov and Rovelli-Vidotto and the "black hole fireworks" model of Haggard-Rovelli. We discuss specifically the role of event and trapping horizons in connection with the behavior of the radiation entropy at future null infinity. We observe in particular that ( i) in the presence of an event horizon the radiation entropy diverges at the end of the evaporation process, ( ii) in models of nonsingular evaporation (with a trapped region but no event horizon) the generalized second law holds only at early times and is violated in the "purifying" phase, ( iii) at late times the radiation entropy can become negative (i.e. the radiation can be less correlated than the vacuum) before going back to zero leading to an up-down-up behavior for the Page curve of a unitarily evaporating black hole.
Sze, Vivienne; Marpe, Detlev
2014-01-01
Context-Based Adaptive Binary Arithmetic Coding (CABAC) is a method of entropy coding first introduced in H.264/AVC and now used in the latest High Efficiency Video Coding (HEVC) standard. While it provides high coding efficiency, the data dependencies in H.264/AVC CABAC make it challenging to parallelize and thus limit its throughput. Accordingly, during the standardization of entropy coding for HEVC, both aspects of coding efficiency and throughput were considered. This chapter describes th...
Productivity benefits of industrial energy efficiency measures
Energy Technology Data Exchange (ETDEWEB)
Worrell, Ernst; Laitner, John A.; Michael, Ruth; Finman, Hodayah
2004-08-30
We review the relationship between energy efficiency improvement measures and productivity in industry. We review over 70 industrial case studies from widely available published databases, followed by an analysis of the representation of productivity benefits in energy modeling. We propose a method to include productivity benefits in the economic assessment of the potential for energy efficiency improvement. The case-study review suggests that energy efficiency investments can provide a significant boost to overall productivity within industry. If this relationship holds, the description of energy-efficient technologies as opportunities for larger productivity improvements has significant implications for conventional economic assessments. The paper explores the implications this change in perspective on the evaluation of energy-efficient technologies for a study of the iron and steel industry in the US. This examination shows that including productivity benefits explicitly in the modeling parameters would double the cost-effective potential for energy efficiency improvement, compared to an analysis excluding those benefits. We provide suggestions for future research in this important area.
International Nuclear Information System (INIS)
Garcia-Morales, Vladimir; Pellicer, Julio; Manzanares, Jose A.
2008-01-01
We present some novel thermodynamic ideas based on the Maupertuis principle. By considering Hamiltonians written in terms of appropriate action-angle variables we show that thermal states can be characterized by the action variables and by their evolution in time when the system is nonintegrable. We propose dynamical definitions for the equilibrium temperature and entropy as well as an expression for the nonequilibrium entropy valid for isolated systems with many degrees of freedom. This entropy is shown to increase in the relaxation to equilibrium of macroscopic systems with short-range interactions, which constitutes a dynamical justification of the Second Law of Thermodynamics. Several examples are worked out to show that this formalism yields the right microcanonical (equilibrium) quantities. The relevance of this approach to nonequilibrium situations is illustrated with an application to a network of coupled oscillators (Kuramoto model). We provide an expression for the entropy production in this system finding that its positive value is directly related to dissipation at the steady state in attaining order through synchronization
DFT study of the hexagonal high-entropy alloy fission product system
Energy Technology Data Exchange (ETDEWEB)
King, D.J.M., E-mail: daniel.miks@live.com [School of Electrical Engineering, University of New South Wales, Kensington, 2052, NSW (Australia); Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Burr, P.A.; Obbard, E.G. [School of Electrical Engineering, University of New South Wales, Kensington, 2052, NSW (Australia); Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Middleburgh, S.C. [Westinghouse Electric Sweden AB, SE-721 63, Västerås (Sweden); Department of Materials, Imperial College London, South Kensington, London, SW7 2AZ (United Kingdom); KTH Royal Institute of Technology, Reactor Physics, 106 91 Stockholm (Sweden)
2017-05-15
The metallic phase fission product containing Mo-Pd-Rh-Ru-Tc can be described as a hexagonal high-entropy alloy (HEA) and is thus investigated using atomic scale simulation techniques relevant to HEAs. Contrary to previous assumptions, the removal of Tc from the system to form the Mo-Pd-Rh-Ru analog is predicted to reduce the stability of the solid solution to the point that σ-Mo{sub 5}Ru{sub 3} may precipitate out at typical fuel operating temperatures. The drive for segregation is attributed to the increased stability of the solid solution with the ejection of Mo and Ru. When Tc is included in the system, a single phase hexagonal solid solution is expected to form for a wider range of compositions. Furthermore, when cooled below 700 °C, this single phase solid solution is predicted to transition to a partially ordered structure. Future studies using the Tc-absent analogue will need to take these structural and chemical deliberations into consideration.
International Nuclear Information System (INIS)
Bianchi, Eugenio; Lorenzo, Tommaso De; Smerlak, Matteo
2015-01-01
We study the dynamics of vacuum entanglement in the process of gravitational collapse and subsequent black hole evaporation. In the first part of the paper, we introduce a covariant regularization of entanglement entropy tailored to curved spacetimes; this regularization allows us to propose precise definitions for the concepts of black hole “exterior entropy” and “radiation entropy.” For a Vaidya model of collapse we find results consistent with the standard thermodynamic properties of Hawking radiation. In the second part of the paper, we compute the vacuum entanglement entropy of various spherically-symmetric spacetimes of interest, including the nonsingular black hole model of Bardeen, Hayward, Frolov and Rovelli-Vidotto and the “black hole fireworks” model of Haggard-Rovelli. We discuss specifically the role of event and trapping horizons in connection with the behavior of the radiation entropy at future null infinity. We observe in particular that (i) in the presence of an event horizon the radiation entropy diverges at the end of the evaporation process, (ii) in models of nonsingular evaporation (with a trapped region but no event horizon) the generalized second law holds only at early times and is violated in the “purifying” phase, (iii) at late times the radiation entropy can become negative (i.e. the radiation can be less correlated than the vacuum) before going back to zero leading to an up-down-up behavior for the Page curve of a unitarily evaporating black hole.
Technical efficiency of irrigated vegetable production among ...
African Journals Online (AJOL)
This study was carried out to analyse the technical efficiency of irrigated vegetable production among smallholder farmers in the guinea savannah, Nigeria, and determine the cost and returns on irrigated vegetable production. Two-stage sampling technique was used, purposive selection of two states and three Local ...
RESOURCE USE EFFICIENCY OF GROUNDNUT PRODUCTION IN ...
African Journals Online (AJOL)
AGROSEARCH UIL
2012-09-28
Sep 28, 2012 ... A stratified sampling technique was employed to select 58 respondents. ... there is still opportunity to increase their production to attain optimal economic efficiency. The ... metric tons and an average productivity of 1.4 metric tons /ha. Developing ... The educated population are gainfully employed in some.
EEG entropy measures in anesthesia
Directory of Open Access Journals (Sweden)
Zhenhu eLiang
2015-02-01
Full Text Available Objective: Entropy algorithms have been widely used in analyzing EEG signals during anesthesia. However, a systematic comparison of these entropy algorithms in assessing anesthesia drugs’ effect is lacking. In this study, we compare the capability of twelve entropy indices for monitoring depth of anesthesia (DoA and detecting the burst suppression pattern (BSP, in anesthesia induced by GA-BAergic agents.Methods: Twelve indices were investigated, namely Response Entropy (RE and State entropy (SE, three wavelet entropy (WE measures (Shannon WE (SWE, Tsallis WE (TWE and Renyi WE (RWE, Hilbert-Huang spectral entropy (HHSE, approximate entropy (ApEn, sample entropy (SampEn, Fuzzy entropy, and three permutation entropy (PE measures (Shannon PE (SPE, Tsallis PE (TPE and Renyi PE (RPE. Two EEG data sets from sevoflurane-induced and isoflu-rane-induced anesthesia respectively were selected to assess the capability of each entropy index in DoA monitoring and BSP detection. To validate the effectiveness of these entropy algorithms, phar-macokinetic / pharmacodynamic (PK/PD modeling and prediction probability analysis were applied. The multifractal detrended fluctuation analysis (MDFA as a non-entropy measure was compared.Results: All the entropy and MDFA indices could track the changes in EEG pattern during different anesthesia states. Three PE measures outperformed the other entropy indices, with less baseline vari-ability, higher coefficient of determination and prediction probability, and RPE performed best; ApEn and SampEn discriminated BSP best. Additionally, these entropy measures showed an ad-vantage in computation efficiency compared with MDFA.Conclusion: Each entropy index has its advantages and disadvantages in estimating DoA. Overall, it is suggested that the RPE index was a superior measure.Significance: Investigating the advantages and disadvantages of these entropy indices could help improve current clinical indices for monitoring DoA.
Production and efficiency analysis with R
Behr, Andreas
2015-01-01
This textbook introduces essential topics and techniques in production and efficiency analysis and shows how to apply these methods using the statistical software R. Numerous small simulations lead to a deeper understanding of random processes assumed in the models and of the behavior of estimation techniques. Step-by-step programming provides an understanding of advanced approaches such as stochastic frontier analysis and stochastic data envelopment analysis. The text is intended for master students interested in empirical production and efficiency analysis. Readers are assumed to have a general background in production economics and econometrics, typically taught in introductory microeconomics and econometrics courses.
PRODUCT EFFICIENCY IN THE SPANISH AUTOMOBILE MARKET
Directory of Open Access Journals (Sweden)
González, Eduardo
2013-01-01
Full Text Available This paper evaluates product efficiency in the Spanish automobile market. We use non parametric frontier techniques in order to estimate product efficiency scores for each model. These scores reflect the minimum price for which each car could be sold, given the bundle of tangible features it offers in comparison to the best-buy models. Unlike previous research, we use discounted prices which have been adjusted by car dealerships to meet sale targets. Therefore, we interpret the efficiency scores as indicators of the value of the intangible features of the brand. The results show that Audi, Volvo, Volkswagen and Mercedes offer the greatest intangible value, since they are heavily overpriced in terms of price/product ratios. Conversely, Seat, Kia, Renault and Dacia are the brands that can be taken as referent in terms of price/product ratios.
Directory of Open Access Journals (Sweden)
Cesare Nardini
2017-04-01
Full Text Available Active-matter systems operate far from equilibrium because of the continuous energy injection at the scale of constituent particles. At larger scales, described by coarse-grained models, the global entropy production rate S quantifies the probability ratio of forward and reversed dynamics and hence the importance of irreversibility at such scales: It vanishes whenever the coarse-grained dynamics of the active system reduces to that of an effective equilibrium model. We evaluate S for a class of scalar stochastic field theories describing the coarse-grained density of self-propelled particles without alignment interactions, capturing such key phenomena as motility-induced phase separation. We show how the entropy production can be decomposed locally (in real space or spectrally (in Fourier space, allowing detailed examination of the spatial structure and correlations that underly departures from equilibrium. For phase-separated systems, the local entropy production is concentrated mainly on interfaces, with a bulk contribution that tends to zero in the weak-noise limit. In homogeneous states, we find a generalized Harada-Sasa relation that directly expresses the entropy production in terms of the wave-vector-dependent deviation from the fluctuation-dissipation relation between response functions and correlators. We discuss extensions to the case where the particle density is coupled to a momentum-conserving solvent and to situations where the particle current, rather than the density, should be chosen as the dynamical field. We expect the new conceptual tools developed here to be broadly useful in the context of active matter, allowing one to distinguish when and where activity plays an essential role in the dynamics.
Adjoint entropy vs topological entropy
Giordano Bruno, Anna
2012-01-01
Recently the adjoint algebraic entropy of endomorphisms of abelian groups was introduced and studied. We generalize the notion of adjoint entropy to continuous endomorphisms of topological abelian groups. Indeed, the adjoint algebraic entropy is defined using the family of all finite-index subgroups, while we take only the subfamily of all open finite-index subgroups to define the topological adjoint entropy. This allows us to compare the (topological) adjoint entropy with the known topologic...
Bernstein, R. B.; Levine, R. D.
1972-01-01
Optimal means of characterizing the distribution of product energy states resulting from reactive collisions of molecules with restricted distributions of initial states are considered, along with those for characterizing the particular reactant state distribution which yields a given set of product states at a specified total energy. It is suggested to represent the energy-dependence of global-type results in the form of square-faced bar plots, and of data for specific-type experiments as triangular-faced prismatic plots. The essential parameters defining the internal state distribution are isolated, and the information content of such a distribution is put on a quantitative basis. The relationship between the information content, the surprisal, and the entropy of the continuous distribution is established. The concept of an entropy deficiency, which characterizes the specificity of product state formation, is suggested as a useful measure of the deviance from statistical behavior. The degradation of information by experimental averaging is considered, leading to bounds on the entropy deficiency.
Measuring capital market efficiency: long-term memory, fractal dimension and approximate entropy
Czech Academy of Sciences Publication Activity Database
Krištoufek, Ladislav; Vošvrda, Miloslav
2014-01-01
Roč. 87, č. 7 (2014), "162-1"-"162-9" ISSN 1434-6028 R&D Projects: GA ČR(CZ) GBP402/12/G097 EU Projects: European Commission(XE) FP7/2007-2013 Program:FP7 Institutional support: RVO:67985556 Keywords : Statistical and Nonlinear Physics * fractal dimension * stock market efficiency Subject RIV: AH - Economics Impact factor: 1.345, year: 2014 http://library.utia.cas.cz/separaty/2014/E/kristoufek-0431151.pdf
Efficient Multi-Label Feature Selection Using Entropy-Based Label Selection
Directory of Open Access Journals (Sweden)
Jaesung Lee
2016-11-01
Full Text Available Multi-label feature selection is designed to select a subset of features according to their importance to multiple labels. This task can be achieved by ranking the dependencies of features and selecting the features with the highest rankings. In a multi-label feature selection problem, the algorithm may be faced with a dataset containing a large number of labels. Because the computational cost of multi-label feature selection increases according to the number of labels, the algorithm may suffer from a degradation in performance when processing very large datasets. In this study, we propose an efficient multi-label feature selection method based on an information-theoretic label selection strategy. By identifying a subset of labels that significantly influence the importance of features, the proposed method efficiently outputs a feature subset. Experimental results demonstrate that the proposed method can identify a feature subset much faster than conventional multi-label feature selection methods for large multi-label datasets.
Malmquist Productivity Index on Efficiency Layers
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F. Rezai balf ∗
2012-09-01
Full Text Available Data Envelopment Analysis (DEA, a popular linear programming technique is useful to rate comparatively operational effiency of decision Making Unit (DMU based on the their deterministic inputoutput data. The Malmquist productivity index in DEA, calculable with the distance function, for measurement the productivity change among two variant time period or two variant group in the same time. This index is based on two factor of efficiency change index and a technological change index. In this paper, we operate on the collective Malmquist productivity index, which performs clustering operation DMUs with classification into different levels of efficient frontier, and then we discuss on the relation between Malmquist index on the efficiency layers and their attractiveness and progress
Efficiency and productivity of hospitals in Vietnam.
Pham, Thuy Linh
2011-01-01
The purpose of this paper is to examine the relative efficiency and productivity of hospitals during the health reform process. Data envelopment analyses method (DEA) with the input-oriented variable-returns-to-scale model was used to calculate efficiency scores. Malmquist total factor productivity index approach was then employed to calculate productivity of hospitals. Data of 101 hospitals was extracted from databases of the Ministry of Health, Vietnam from the years 1998 to 2006. There was evidence of improvement in overall technical efficiency from 65 per cent in 1998 to 76 per cent in 2006. Hospitals' productivity progressed around 1.4 per cent per year, which was mainly due to the technical efficiency improvement. Furthermore, provincial hospitals were more technically efficient than their central counterparts and hospitals located in different regions performed differently. The paper provides an insight in the performance of Vietnamese public hospitals that has been rarely examined before and contributes to the existing literature of hospital performance in developing countries
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.
Gutierrez-Jurado, H. A.; Guan, H.; Wang, J.; Wang, H.; Bras, R. L.; Simmons, C. T.
2015-12-01
Quantification of evapotranspiration (ET) and its partition over regions of heterogeneous topography and canopy poses a challenge using traditional approaches. In this study, we report the results of a novel field experiment design guided by the Maximum Entropy Production model of ET (MEP-ET), formulated for estimating evaporation and transpiration from homogeneous soil and canopy. A catchment with complex terrain and patchy vegetation in South Australia was instrumented to measure temperature, humidity and net radiation at soil and canopy surfaces. Performance of the MEP-ET model to quantify transpiration and soil evaporation was evaluated during wet and dry conditions with independently and directly measured transpiration from sapflow and soil evaporation using the Bowen Ratio Energy Balance (BREB). MEP-ET transpiration shows remarkable agreement with that obtained through sapflow measurements during wet conditions, but consistently overestimates the flux during dry periods. However, an additional term introduced to the original MEP-ET model accounting for higher stomatal regulation during dry spells, based on differences between leaf and air vapor pressure deficits and temperatures, significantly improves the model performance. On the other hand, MEP-ET soil evaporation is in good agreement with that from BREB regardless of moisture conditions. The experimental design allows a plot and tree scale quantification of evaporation and transpiration respectively. This study confirms for the first time that the MEP-ET originally developed for homogeneous open bare soil and closed canopy can be used for modeling ET over heterogeneous land surfaces. Furthermore, we show that with the addition of an empirical function simulating the plants ability to regulate transpiration, and based on the same measurements of temperature and humidity, the method can produce reliable estimates of ET during both wet and dry conditions without compromising its parsimony.
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
Kleidon, A
2010-05-12
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.
Piecewise Loglinear Estimation of Efficient Production Surfaces
Rajiv D. Banker; Ajay Maindiratta
1986-01-01
Linear programming formulations for piecewise loglinear estimation of efficient production surfaces are derived from a set of basic properties postulated for the underlying production possibility sets. Unlike the piecewise linear model of Banker, Charnes, and Cooper (Banker R. D., A. Charnes, W. W. Cooper. 1984. Models for the estimation of technical and scale inefficiencies in data envelopment analysis. Management Sci. 30 (September) 1078--1092.), this approach permits the identification of ...
Productivity and production efficiency among small scale irrigated ...
African Journals Online (AJOL)
The study examined productivity and production efficiency among small scale irrigated sugarcane farmers in Niger State, Nigeria using a stochastic translog frontier function. Data for the study were obtained using structured questionnaires administered to 100 randomly selected sugarcane farmers from Paiko and Gurara ...
Roots, plant production and nutrient use efficiency
Willigen, de P.; Noordwijk, van M.
1987-01-01
The role of roots in obtaining high crop production levels as well as a high nutrient use efficiency is discussed. Mathematical models of diffusion and massflow of solutes towards roots are developed for a constant daily uptake requirement. Analytical solutions are given for simple and more
Methionine supplementation in the productive efficiency, carcass ...
African Journals Online (AJOL)
The effect of dietary methionine supplementation at varying levels on the productive efficiency, carcass characteristics and economics of growing indigenous turkey was investigated. Four Isocaloric and Isonitrogenous diets were formulated. The diets were supplemented with 0.00%, 0.05%, 0.10%, and 0.15% respectively.
Labour productivity and resource use efficiency amongst ...
African Journals Online (AJOL)
The study examined labour productivity and resource efficiency amongst smallholder cocoa farmers in Abia State, Nigeria. A purposive random sampling technique was adopted in selecting 60 cocoa farmers from three agricultural zones in the State. The analytical techniques used involve inferential statistics like means, ...
Production Efficiency Audit on Tea Beverage Agroindustry
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Hendra Adiyatna, . Marimin
2001-04-01
Full Text Available The objective of this work was to investigate and to apply economic efficiency performance measurement methods for tea beverage agroindustry. These measurements were based on twelve technique and economic efficiency criteria, which illustrate the condition of the processes. This illustration was able to explain the material and the energy utilization, variance of the processes and product, handling of the waste and acceptance in the market. The methodology was divided into three steps: (1 defining the technique and the economic criteria, appropriate to the circumstance of the processes, (2 state efficiency the level status, (3 evaluation and structure prioritizing of the processes improvement alternatives. The results of this work indicates that there are seven appropriate criteria. The status of the efficiency is in the medium level. The improvement priorities recommended include optimization of material and energy usage and minimization of breaktime of the critical processes
International Nuclear Information System (INIS)
Chavanis, Pierre-Henri
2014-01-01
In the context of two-dimensional (2D) turbulence, we apply the maximum entropy production principle (MEPP) by enforcing a local conservation of energy. This leads to an equation for the vorticity distribution that conserves all the Casimirs, the energy, and that increases monotonically the mixing entropy (H-theorem). Furthermore, the equation for the coarse-grained vorticity dissipates monotonically all the generalized enstrophies. These equations may provide a parametrization of 2D turbulence. They do not generally relax towards the maximum entropy state. The vorticity current vanishes for any steady state of the 2D Euler equation. Interestingly, the equation for the coarse-grained vorticity obtained from the MEPP turns out to coincide, after some algebraic manipulations, with the one obtained with the anticipated vorticity method. This shows a connection between these two approaches when the conservation of energy is treated locally. Furthermore, the newly derived equation, which incorporates a diffusion term and a drift term, has a nice physical interpretation in terms of a selective decay principle. This sheds new light on both the MEPP and the anticipated vorticity method. (paper)
EEG entropy measures in anesthesia
Liang, Zhenhu; Wang, Yinghua; Sun, Xue; Li, Duan; Voss, Logan J.; Sleigh, Jamie W.; Hagihira, Satoshi; Li, Xiaoli
2015-01-01
efficiency compared with MDFA. Conclusion: Each entropy index has its advantages and disadvantages in estimating DoA. Overall, it is suggested that the RPE index was a superior measure. Investigating the advantages and disadvantages of these entropy indices could help improve current clinical indices for monitoring DoA. PMID:25741277
Productive efficiency in the banking industry
Directory of Open Access Journals (Sweden)
Martín Leandro Dutto Giolongo
2016-07-01
Full Text Available The goal of this paper is to estimate the productive efficiency of Argentine banks. For this purpose, panel data of the universe of banks under the supervision of the Central Bank of the Republic of Argentina (BCRA has been collected. In order to build the bank´s indicators, we used a database of 66 institutions, with annual information for the period 2009-2013. The sources of information were both the BCRA´s web site (www.bcra.gov.ar, and the Buenos Aires Stock Exchange´s web site (www.bolsar.com. It has been selected an efficiency indicator ranging between 0 and 1, meaning the lowest and highest level of efficiency, respectively. The concept of efficiency used here is a relative one, because it considers a Bank´s performance in relation to the behavior of the best players in the industry, being the latter the base of the industry benchmark or frontier. The results show that the mean efficiency of Argentine banks is 0,8277 in the specific period under consideration. The comparison with the results of other studies relating efficiency and competitive pressure, didn´t allow us to infer that the Argentine banking industry experienced in the period a high level of competition
ECONOMIC EFFICIENCY IN TOMATOES PRODUCTION IN GREENHOUSES
Directory of Open Access Journals (Sweden)
A POPESCU
2003-07-01
Full Text Available This study aimed to appreciate the evolution of economic efficiency in tomatoes production in greenhouses within a private firm situated next to the capital. The firm owns 4 ha greenhouses and the weight of tomatoes crop in the cultivated area is just 38.75 %. In fact, during the last three years, the tomatoes cultivated surface has been diminished in favour of flowers production which, like tomatoes production is an important income source for any producer. The reduction of the tomatoes cultivated area was compensated by the increase of intensification grade using new high performance hybrids and modern technologies. Thus, the scientific production management has been looking for maintaining the total production at the same level from a year to another by an increased average tomatoes yield by 53.33 % . The continuous increase of farm input price has doubled the cost per surface unit and increased the cost per tomatoes kilogram by 33 %. The increase of tomatoes demand and of market price by 31 % have had a positive influence on the farm incomes which has doubled during the last three years. In the year 2000, the company has obtained USD 41,818 income/ha of which subtracting the related production cost we can easily get USD 4,815 profit/ha. The average profit rate recorded by the firm is 13 % in the period 2000-2002, when the study was made. As a conclusion, tomatoes production in greenhouses is a good deal. To keep a high economic efficiency, under the diminishing of the cultivated area, the producers have to increase average tomatoes production by using high performance technology based on high economic value hybrids.
Lorenz, Ralph D
2010-05-12
The 'two-box model' of planetary climate is discussed. This model has been used to demonstrate consistency of the equator-pole temperature gradient on Earth, Mars and Titan with what would be predicted from a principle of maximum entropy production (MEP). While useful for exposition and for generating first-order estimates of planetary heat transports, it has too low a resolution to investigate climate systems with strong feedbacks. A two-box MEP model agrees well with the observed day : night temperature contrast observed on the extrasolar planet HD 189733b.
Entropy of international trades
Oh, Chang-Young; Lee, D.-S.
2017-05-01
The organization of international trades is highly complex under the collective efforts towards economic profits of participating countries given inhomogeneous resources for production. Considering the trade flux as the probability of exporting a product from a country to another, we evaluate the entropy of the world trades in the period 1950-2000. The trade entropy has increased with time, and we show that it is mainly due to the extension of trade partnership. For a given number of trade partners, the mean trade entropy is about 60% of the maximum possible entropy, independent of time, which can be regarded as a characteristic of the trade fluxes' heterogeneity and is shown to be derived from the scaling and functional behaviors of the universal trade-flux distribution. The correlation and time evolution of the individual countries' gross-domestic products and the number of trade partners show that most countries achieved their economic growth partly by extending their trade relationship.
Nonsymmetric entropy and maximum nonsymmetric entropy principle
International Nuclear Information System (INIS)
Liu Chengshi
2009-01-01
Under the frame of a statistical model, the concept of nonsymmetric entropy which generalizes the concepts of Boltzmann's entropy and Shannon's entropy, is defined. Maximum nonsymmetric entropy principle is proved. Some important distribution laws such as power law, can be derived from this principle naturally. Especially, nonsymmetric entropy is more convenient than other entropy such as Tsallis's entropy in deriving power laws.
International Nuclear Information System (INIS)
De Nicola, Sergio; Fedele, Renato; Man'ko, Margarita A; Man'ko, Vladimir I
2007-01-01
The tomographic-probability description of quantum states is reviewed. The symplectic tomography of quantum states with continuous variables is studied. The symplectic entropy of the states with continuous variables is discussed and its relation to Shannon entropy and information is elucidated. The known entropic uncertainty relations of the probability distribution in position and momentum of a particle are extended and new uncertainty relations for symplectic entropy are obtained. The partial case of symplectic entropy, which is optical entropy of quantum states, is considered. The entropy associated to optical tomogram is shown to satisfy the new entropic uncertainty relation. The example of Gaussian states of harmonic oscillator is studied and the entropic uncertainty relations for optical tomograms of the Gaussian state are shown to minimize the uncertainty relation
International Nuclear Information System (INIS)
Maes, Christian
2012-01-01
In contrast to the quite unique entropy concept useful for systems in (local) thermodynamic equilibrium, there is a variety of quite distinct nonequilibrium entropies, reflecting different physical points. We disentangle these entropies as they relate to heat, fluctuations, response, time asymmetry, variational principles, monotonicity, volume contraction or statistical forces. However, not all of those extensions yield state quantities as understood thermodynamically. At the end we sketch how aspects of dynamical activity can take over for obtaining an extended Clausius relation.
Efficiency in energy production and consumption
Kellogg, Ryan Mayer
This dissertation deals with economic efficiency in the energy industry and consists of three parts. The first examines how joint experience between pairs of firms working together in oil and gas drilling improves productivity. Part two asks whether oil producers time their drilling optimally by taking real options effects into consideration. Finally, I investigate the efficiency with which energy is consumed, asking whether extending Daylight Saving Time (DST) reduces electricity use. The chapter "Learning by Drilling: Inter-Firm Learning and Relationship Persistence in the Texas Oilpatch" examines how oil production companies and the drilling rigs they hire improve drilling productivity by learning through joint experience. I find that the joint productivity of a lead firm and its drilling contractor is enhanced significantly as they accumulate experience working together. Moreover, this result is robust to other relationship specificities and standard firm-specific learning-by-doing effects. The second chapter, "Drill Now or Drill Later: The Effect of Expected Volatility on Investment," investigates the extent to which firms' drilling behavior accords with a key prescription of real options theory: irreversible investments such as drilling should be deferred when the expected volatility of the investments' payoffs increases. I combine detailed data on oil drilling with expectations of future oil price volatility that I derive from the NYMEX futures options market. Conditioning on expected price levels, I find that oil production companies significantly reduce the number of wells they drill when expected price volatility is high. I conclude with "Daylight Time and Energy: Evidence from an Australian Experiment," co-authored with Hendrik Wolff. This chapter assesses DST's impact on electricity demand using a quasi-experiment in which parts of Australia extended DST in 2000 to facilitate the Sydney Olympics. We show that the extension did not reduce overall
Machine Selection in A Dairy Product Company with Entropy and SAW Method Integration
Directory of Open Access Journals (Sweden)
Aşkın Özdağoğlu
2017-07-01
Full Text Available Machine selection is an important and difficult process for the firms, and its results may generate more problems than anticipated. In order to find the best alternative, managers should define the requirements of the factory and determine the necessary criteria. On the other hand, the decision making criteria in order to choose the right equipment may vary according to the type of the manufacturing facility, market requirements, and consumer assigned criteria. This study aims to find the best machine alternative among the three machine offerings according to twelve evaluation criteria by integrating entropy method with SAW method.
Mass-independent area (or entropy) and thermodynamic volume products in conformal gravity
Pradhan, Parthapratim
2017-06-01
In this work, we investigate the thermodynamic properties of conformal gravity in four dimensions. We compute the area (or entropy) functional relation for this black hole (BH). We consider both de Sitter (dS) and anti-de Sitter (AdS) cases. We derive the Cosmic-Censorship-Inequality which is an important relation in general relativity that relates the total mass of a spacetime to the area of all the BH horizons. Local thermodynamic stability is studied by computing the specific heat. The second-order phase transition occurs at a certain condition. Various types of second-order phase structure have been given for various values of a and the cosmological constant Λ in the Appendix. When a = 0, one obtains the result of Schwarzschild-dS and Schwarzschild-AdS cases. In the limit aM ≪ 1, one obtains the result of Grumiller spacetime, where a is nontrivial Rindler parameter or Rindler acceleration and M is the mass parameter. The thermodynamic volume functional relation is derived in the extended phase space, where the cosmological constant is treated as a thermodynamic pressure and its conjugate variable as a thermodynamic volume. The mass-independent area (or entropy) functional relation and thermodynamic volume functional relation that we have derived could turn out to be a universal quantity.
Matthaeus, W. H.; Yang, Y.; Servidio, S.; Parashar, T.; Chasapis, A.; Roytershteyn, V.
2017-12-01
Turbulence cascade transfers energy from large scale to small scale but what happens once kinetic scales are reached? In a collisional medium, viscosity and resistivity remove fluctuation energy in favor of heat. In the weakly collisional solar wind, (or corona, m-sheath, etc.), the sequence of events must be different. Heating occurs, but through what mechanisms? In standard approaches, dissipation occurs though linear wave modes or instabilities and one seeks to identify them. A complementary view is that cascade leads to several channels of energy conversion, interchange and spatial rearrangement that collectively leads to production of internal energy. Channels may be described using compressible MHD & multispecies Vlasov Maxwell formulations. Key steps are: Conservative rearrangement of energy in space; Parallel incompressible and compressible cascades - conservative rearrangment in scale; electromagnetic work on particles that drives flows, both macroscopic and microscopic; and pressure-stress interactions, both compressive and shear-like, that produces internal energy. Examples given from MHD, PIC simulations and MMS observations. A more subtle issue is how entropy is related to this degeneration (or, "dissipation") of macroscopic, fluid-scale fluctuations. We discuss this in terms of Boltzmann and thermodynamic entropies, and velocity space effects of collisions.
Structural Materials for Efficient Energy Production Systems
International Nuclear Information System (INIS)
Gomez Briceno, D.
2009-01-01
Increasing the efficiency of electric power production systems implies increasing the operating temperature above those of systems currently in operation. The viability of new systems depends completely on the availability of structural materials that withstand the operating conditions specified in the design: adequate features under mechanical stress at high temperatures and compatibility with the medium. In the case of nuclear systems (fission, fusion), an important requirement is their response to irradiation induced damage. In spite of the significant differences that exist in the design of nuclear power plants, fusion reactors, innovative fission systems, supercritical fossil plants, biomass plants, solar concentration thermal plants, etc., all of them have as a common characteristic the use of resistant materials at high temperatures. The qualification of existing materials for the new and more demanding operating conditions and the development of new materials is one of the challenges faced by the electric power production industry. The science of materials and the understanding of the basic processes that take place in structural materials on exposure to the operating conditions of energy production systems are the tools that are available to obtain safe and economically viable solutions. (Authors) 4 refs.
Entropy, matter, and cosmology.
Prigogine, I; Géhéniau, J
1986-09-01
The role of irreversible processes corresponding to creation of matter in general relativity is investigated. The use of Landau-Lifshitz pseudotensors together with conformal (Minkowski) coordinates suggests that this creation took place in the early universe at the stage of the variation of the conformal factor. The entropy production in this creation process is calculated. It is shown that these dissipative processes lead to the possibility of cosmological models that start from empty conditions and gradually build up matter and entropy. Gravitational entropy takes a simple meaning as associated to the entropy that is necessary to produce matter. This leads to an extension of the third law of thermodynamics, as now the zero point of entropy becomes the space-time structure out of which matter is generated. The theory can be put into a convenient form using a supplementary "C" field in Einstein's field equations. The role of the C field is to express the coupling between gravitation and matter leading to irreversible entropy production.
Catalysts for Efficient Production of Carbon Nanotubes
Sun, Ted X.; Dong, Yi
2009-01-01
Several metal alloys have shown promise as improved catalysts for catalytic thermal decomposition of hydrocarbon gases to produce carbon nanotubes (CNTs). Heretofore almost every experiment on the production of carbon nanotubes by this method has involved the use of iron, nickel, or cobalt as the catalyst. However, the catalytic-conversion efficiencies of these metals have been observed to be limited. The identification of better catalysts is part of a continuing program to develop means of mass production of high-quality carbon nanotubes at costs lower than those achieved thus far (as much as $100/g for purified multi-wall CNTs or $1,000/g for single-wall CNTs in year 2002). The main effort thus far in this program has been the design and implementation of a process tailored specifically for high-throughput screening of alloys for catalyzing the growth of CNTs. The process includes an integral combination of (1) formulation of libraries of catalysts, (2) synthesis of CNTs from decomposition of ethylene on powders of the alloys in a pyrolytic chemical-vapor-decomposition reactor, and (3) scanning- electron-microscope screening of the CNTs thus synthesized to evaluate the catalytic efficiencies of the alloys. Information gained in this process is put into a database and analyzed to identify promising alloy compositions, which are to be subjected to further evaluation in a subsequent round of testing. Some of these alloys have been found to catalyze the formation of carbon nano tubes from ethylene at temperatures as low as 350 to 400 C. In contrast, the temperatures typically required for prior catalysts range from 550 to 750 C.
Business strategies, profitability and efficiency of production
Directory of Open Access Journals (Sweden)
S. Alarcón
2013-02-01
Full Text Available The strategy choices of market-oriented companies are a topic now under wide investigation in the analysis of business performance antecedents. The purpose of this study is to examine the outcomes of the combination of three different organizational strategies (market orientation, innovativeness and entrepreneurial orientation on business performance indicators. Models using profitability and efficiency indicators are proposed with the specific aim of obtaining a deeper analysis of the relative roles played by each. The empirical work takes place in the agro-food industry in the Ebro Valley, one of Spain’s most competitive regions. The estimates from profitability quantile and truncated regressions of the efficiency scores reveal that market orientation has a positive effect on economic and productivity performance. The impact of pro-active, innovation-seeking, and risk-averse entrepreneurship is nevertheless more debatable, despite some influence of these entrepreneurial styles on observed performance values. This enables conclusions regarding the possibility of combining a market-oriented business culture with innovation and entrepreneurial activity with a view to obtaining business performance gains.
Indian Academy of Sciences (India)
Abstract. It is shown that (i) every probability density is the unique maximizer of relative entropy in an appropriate class and (ii) in the class of all pdf f that satisfy. ∫ fhi dμ = λi for i = 1, 2,...,...k the maximizer of entropy is an f0 that is pro- portional to exp(. ∑ ci hi ) for some choice of ci . An extension of this to a continuum of.
Indian Academy of Sciences (India)
It is shown that (i) every probability density is the unique maximizer of relative entropy in an appropriate class and (ii) in the class of all pdf that satisfy ∫ f h i d = i for i = 1 , 2 , … , … k the maximizer of entropy is an f 0 that is proportional to exp ( ∑ c i h i ) for some choice of c i . An extension of this to a continuum of ...
Directory of Open Access Journals (Sweden)
Tommaso Toffoli
2016-06-01
Full Text Available Here we deconstruct, and then in a reasoned way reconstruct, the concept of “entropy of a system”, paying particular attention to where the randomness may be coming from. We start with the core concept of entropy as a count associated with a description; this count (traditionally expressed in logarithmic form for a number of good reasons is in essence the number of possibilities—specific instances or “scenarios”—that match that description. Very natural (and virtually inescapable generalizations of the idea of description are the probability distribution and its quantum mechanical counterpart, the density operator. We track the process of dynamically updating entropy as a system evolves. Three factors may cause entropy to change: (1 the system’s internal dynamics; (2 unsolicited external influences on it; and (3 the approximations one has to make when one tries to predict the system’s future state. The latter task is usually hampered by hard-to-quantify aspects of the original description, limited data storage and processing resource, and possibly algorithmic inadequacy. Factors 2 and 3 introduce randomness—often huge amounts of it—into one’s predictions and accordingly degrade them. When forecasting, as long as the entropy bookkeping is conducted in an honest fashion, this degradation will always lead to an entropy increase. To clarify the above point we introduce the notion of honest entropy, which coalesces much of what is of course already done, often tacitly, in responsible entropy-bookkeping practice. This notion—we believe—will help to fill an expressivity gap in scientific discourse. With its help, we shall prove that any dynamical system—not just our physical universe—strictly obeys Clausius’s original formulation of the second law of thermodynamics if and only if it is invertible. Thus this law is a tautological property of invertible systems!
Contracting for Efficiency. A Best Practices Guide for Energy-Efficient Product Procurement
Energy Technology Data Exchange (ETDEWEB)
Bunch, Saralyn [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Payne, Christopher [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2016-04-01
The requirement to buy energy- and water-efficient products applies to federal purchases made through any procurement pathway (e.g., purchase cards, e-retailers, and solicitations) and to a wide variety of federal projects. The Federal Energy Management Program’s (FEMP's) Buy Energy-Efficient Products buyer overview fact sheet and Contracting for Efficiency best practices guide for product procurement are designed to support federal buyers in the purchase of energy- and water-efficient products.
Contracting for Efficiency: A Best Practices Guide for Energy Efficient Product Procurement
Energy Technology Data Exchange (ETDEWEB)
Bunch, Saralyn [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Payne, Christopher [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2017-11-01
The requirement to buy energy- and water-efficient products applies to federal purchases made through any procurement pathway (e.g., purchase cards, e-retailers, and solicitations) and to a wide variety of federal projects. The Federal Energy Management Program’s (FEMP's) Buy Energy-Efficient Products buyer overview fact sheet and Contracting for Efficiency best practices guide for product procurement are designed to support federal buyers in the purchase of energy- and water-efficient products.
Production of Energy Efficient Preform Structures (PEEPS)
Energy Technology Data Exchange (ETDEWEB)
Dr. John A. Baumann
2012-06-08
Due to its low density, good structural characteristics, excellent fabrication properties, and attractive appearance, aluminum metal and its alloys continue to be widely utilized. The transportation industry continues to be the largest consumer of aluminum products, with aerospace as the principal driver for this use. Boeing has long been the largest single company consumer of heat-treated aluminum in the U.S. The extensive use of aluminum to build aircraft and launch vehicles has been sustained, despite the growing reliance on more structurally efficient carbon fiber reinforced composite materials. The trend in the aerospace industry over the past several decades has been to rely extensively on large, complex, thin-walled, monolithic machined structural components, which are fabricated from heavy billets and thick plate using high speed machining. The use of these high buy-to-fly ratio starting product forms, while currently cost effective, is energy inefficient, with a high environmental impact. The widespread implementation of Solid State Joining (SSJ) technologies, to produce lower buy-to-fly ratio starting forms, tailored to each specific application, offers the potential for a more sustainable manufacturing strategy, which would consume less energy, require less material, and reduce material and manufacturing costs. One objective of this project was to project the energy benefits of using SSJ techniques to produce high-performance aluminum structures if implemented in the production of the world fleet of commercial aircraft. A further objective was to produce an energy consumption prediction model, capable of calculating the total energy consumption, solid waste burden, acidification potential, and CO2 burden in producing a starting product form - whether by conventional or SSJ processes - and machining that to a final part configuration. The model needed to be capable of computing and comparing, on an individual part/geometry basis, multiple possible
Management of efficiency of agricultural production on the basis of ...
African Journals Online (AJOL)
Management of efficiency of agricultural production on the basis of margin approach. ... Journal of Fundamental and Applied Sciences ... and systematized to the management of production costs of agricultural products, the proposed definition ...
Changes in production efficiency in China identification and measuring
Xu, Bing; Watada, Junzo
2014-01-01
Evaluating Production Efficiency in China examines production from engineering and statistics perspectives rather than from economics and mathematics perspectives. The authors present an observable benchmark as the criterion of the production efficiency to replace the unobservable production frontier surface. This book discusses several different computing technologies, controllable variable as a path of identification, changes in production efficiency by decision making on specific operating conditions, and optimal resource allocation. The book provides a channel to tap inside the success stories of China, exploiting the way of changes in production efficiency during China’s development in the past 30 years. This book examines the concepts and realization of production efficiencies across all areas of the economy. Also the book provides the perspective of foreign direct investment (FDI) absorption to identify how Chinese economy changes in production efficiency.
Entropy dynamics in cone production of longleaf pine forests in the southeastern United States
Xiongwen Chen; Dale G. Brockway; Qinfeng Guo
2016-01-01
Sporadic temporal patterns of seed production are a challenge for the regeneration and restoration of longleaf pine, which is a keystone component of an endangered ecosystem in the southeastern United States. In this study, long-term data for longleaf pine cone production, collected at six sites across the southeastern region, was examined from the perspective of...
Entropy Generation Minimization in Dimethyl Ether Synthesis: A Case Study
Kingston, Diego; Razzitte, Adrián César
2018-04-01
Entropy generation minimization is a method that helps improve the efficiency of real processes and devices. In this article, we study the entropy production (due to chemical reactions, heat exchange and friction) in a conventional reactor that synthesizes dimethyl ether and minimize it by modifying different operating variables of the reactor, such as composition, temperature and pressure, while aiming at a fixed production of dimethyl ether. Our results indicate that it is possible to reduce the entropy production rate by nearly 70 % and that, by changing only the inlet composition, it is possible to cut it by nearly 40 %, though this comes at the expense of greater dissipation due to heat transfer. We also study the alternative of coupling the reactor with another, where dehydrogenation of methylcyclohexane takes place. In that case, entropy generation can be reduced by 54 %, when pressure, temperature and inlet molar flows are varied. These examples show that entropy generation analysis can be a valuable tool in engineering design and applications aiming at process intensification and efficient operation of plant equipment.
Using entropy measures to characterize human locomotion.
Leverick, Graham; Szturm, Tony; Wu, Christine Q
2014-12-01
Entropy measures have been widely used to quantify the complexity of theoretical and experimental dynamical systems. In this paper, the value of using entropy measures to characterize human locomotion is demonstrated based on their construct validity, predictive validity in a simple model of human walking and convergent validity in an experimental study. Results show that four of the five considered entropy measures increase meaningfully with the increased probability of falling in a simple passive bipedal walker model. The same four entropy measures also experienced statistically significant increases in response to increasing age and gait impairment caused by cognitive interference in an experimental study. Of the considered entropy measures, the proposed quantized dynamical entropy (QDE) and quantization-based approximation of sample entropy (QASE) offered the best combination of sensitivity to changes in gait dynamics and computational efficiency. Based on these results, entropy appears to be a viable candidate for assessing the stability of human locomotion.
International Nuclear Information System (INIS)
Hudetz, T.
1989-01-01
As a 'by-product' of the Connes-Narnhofer-Thirring theory of dynamical entropy for (originally non-Abelian) nuclear C * -algebras, the well-known variational principle for topological entropy is eqivalently reformulated in purly algebraically defined terms for (separable) Abelian C * -algebras. This 'algebraic variational principle' should not only nicely illustrate the 'feed-back' of methods developed for quantum dynamical systems to the classical theory, but it could also be proved directly by 'algebraic' methods and could thus further simplify the original proof of the variational principle (at least 'in principle'). 23 refs. (Author)
Maximum entropy tokamak configurations
International Nuclear Information System (INIS)
Minardi, E.
1989-01-01
The new entropy concept for the collective magnetic equilibria is applied to the description of the states of a tokamak subject to ohmic and auxiliary heating. The condition for the existence of steady state plasma states with vanishing entropy production implies, on one hand, the resilience of specific current density profiles and, on the other, severe restrictions on the scaling of the confinement time with power and current. These restrictions are consistent with Goldston scaling and with the existence of a heat pinch. (author)
Microscopic entropy and nonlocality
International Nuclear Information System (INIS)
Karpov, E.; Ordonets, G.; Petroskij, T.; Prigozhin, I.
2003-01-01
We have obtained a microscopic expression for entropy in terms of H function based on nonunitary Λ transformation which leads from the time evolution as a unitary group to a Markovian dynamics and unifies the reversible and irreversible aspects of quantum mechanics. This requires a new representation outside the Hilbert space. In terms of H, we show the entropy production and the entropy flow during the emission and absorption of radiation by an atom. Analyzing the time inversion experiment, we emphasize the importance of pre- and postcollisional correlations, which break the symmetry between incoming and outgoing waves. We consider the angle dependence of the H function in a three-dimensional situation. A model including virtual transitions is discussed in a subsequent paper
Directory of Open Access Journals (Sweden)
Luca Faes
2017-01-01
Full Text Available The most common approach to assess the dynamical complexity of a time series across multiple temporal scales makes use of the multiscale entropy (MSE and refined MSE (RMSE measures. In spite of their popularity, MSE and RMSE lack an analytical framework allowing their calculation for known dynamic processes and cannot be reliably computed over short time series. To overcome these limitations, we propose a method to assess RMSE for autoregressive (AR stochastic processes. The method makes use of linear state-space (SS models to provide the multiscale parametric representation of an AR process observed at different time scales and exploits the SS parameters to quantify analytically the complexity of the process. The resulting linear MSE (LMSE measure is first tested in simulations, both theoretically to relate the multiscale complexity of AR processes to their dynamical properties and over short process realizations to assess its computational reliability in comparison with RMSE. Then, it is applied to the time series of heart period, arterial pressure, and respiration measured for healthy subjects monitored in resting conditions and during physiological stress. This application to short-term cardiovascular variability documents that LMSE can describe better than RMSE the activity of physiological mechanisms producing biological oscillations at different temporal scales.
From Policy to Compliance: Federal Energy Efficient Product Procurement
Energy Technology Data Exchange (ETDEWEB)
DeMates, Laurèn [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Scodel, Anna [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
2017-09-06
Federal buyers are required to purchase energy-efficient products in an effort to minimize energy use in the federal sector, save the federal government money, and spur market development of efficient products. The Federal Energy Management Program (FEMP)’s Energy Efficient Product Procurement (EEPP) Program helps federal agencies comply with the requirement to purchase energy-efficient products by providing technical assistance and guidance and setting efficiency requirements for certain product categories. Past studies have estimated the savings potential of purchasing energy-efficient products at over $500 million per year in energy costs across federal agencies.1 Despite the strong policy support for EEPP and resources available, energy-efficient product purchasing operates within complex decision-making processes and operational structures; implementation challenges exist that may hinder agencies’ ability to comply with purchasing requirements. The shift to purchasing green products, including energy-efficient products, relies on “buy in” from a variety of potential actors throughout different purchasing pathways. Challenges may be especially high for EEPP relative to other sustainable acquisition programs given that efficient products frequently have a higher first cost than non-efficient ones, which may be perceived as a conflict with fiscal responsibility, or more simply problematic for agency personnel trying to stretch limited budgets. Federal buyers may also face challenges in determining whether a given product is subject to EEPP requirements. Previous analysis on agency compliance with EEPP, conducted by the Alliance to Save Energy (ASE), shows that federal agencies are getting better at purchasing energy-efficient products. ASE conducted two reviews of relevant solicitations for product and service contracts listed on Federal Business Opportunities (FBO), the centralized website where federal agencies are required to post procurements greater
Shannon versus Kullback-Leibler entropies in nonequilibrium random motion
International Nuclear Information System (INIS)
Garbaczewski, Piotr
2005-01-01
We analyze dynamical properties of the Shannon information entropy of a continuous probability distribution, which is driven by a standard diffusion process. This entropy choice is confronted with another option, employing the conditional Kullback-Leibler entropy. Both entropies discriminate among various probability distributions, either statically or in the time domain. An asymptotic approach towards equilibrium is typically monotonic in terms of the Kullback entropy. The Shannon entropy time rate needs not to be positive and is a sensitive indicator of the power transfer processes (removal/supply) due to an active environment. In the case of Smoluchowski diffusions, the Kullback entropy time rate coincides with the Shannon entropy 'production' rate
Efficient Product Customization by Structure Synthesis
Maurer, M.;Rupp, T.;Lindemann, U.
2017-01-01
The presented approach describes a new strategy for creating product structures, which are suitable for further customer driven product customization – i.e. the customization can be carried out within less time and for lower costs. The required input data is knowledge on the interconnectivity between product components and knowledge of principal scopes of customization demands (e.g. which components or functions customers would like to individualize, which ones are unknown or hidden). By mean...
Upper entropy axioms and lower entropy axioms
International Nuclear Information System (INIS)
Guo, Jin-Li; Suo, Qi
2015-01-01
The paper suggests the concepts of an upper entropy and a lower entropy. We propose a new axiomatic definition, namely, upper entropy axioms, inspired by axioms of metric spaces, and also formulate lower entropy axioms. We also develop weak upper entropy axioms and weak lower entropy axioms. Their conditions are weaker than those of Shannon–Khinchin axioms and Tsallis axioms, while these conditions are stronger than those of the axiomatics based on the first three Shannon–Khinchin axioms. The subadditivity and strong subadditivity of entropy are obtained in the new axiomatics. Tsallis statistics is a special case of satisfying our axioms. Moreover, different forms of information measures, such as Shannon entropy, Daroczy entropy, Tsallis entropy and other entropies, can be unified under the same axiomatics
International Nuclear Information System (INIS)
Kawazura, Y.; Yoshida, Z.
2012-01-01
Two different types of self-organizing and sustaining ordered motion in fluids or plasmas--one is a Benard convection (or streamer) and the other is a zonal flow--have been compared by introducing a thermodynamic phenomenological model and evaluating the corresponding entropy production rates (EP). These two systems have different topologies in their equivalent circuits: the Benard convection is modeled by parallel connection of linear and nonlinear conductances, while the zonal flow is modeled by series connection. The ''power supply'' that drives the systems is also a determinant of operating modes. When the energy flux is a control parameter (as in usual plasma experiments), the driver is modeled by a constant-current power supply, and when the temperature difference between two separate boundaries is controlled (as in usual computational studies), the driver is modeled by a constant-voltage power supply. The parallel (series)-connection system tends to minimize (maximize) the total EP when a constant-current power supply drives the system. This minimum/maximum relation flips when a constant-voltage power supply is connected.
Analyzing the complexity of cone production in longleaf pine by multiscale entropy
Xiongwen Chen; Qinfeng Guo; Dale G. Brockway
2016-01-01
The longleaf pine (Pinus palustris Mill.) forests are important ecosystems in the southeastern USA because of their ecological and economic value. Since European settlement, longleaf pine ecosystems have dramatically declined in extent, to the degree that they are now listed as endangered ecosystems. Its sporadic seed production, which...
Photobiological hydrogen production : photochemical efficiency and bioreactor design
Akkerman, I.; Janssen, M.; Rocha, J.; Wijffels, R.H.
2002-01-01
Biological production of hydrogen can be carried out by photoautotrophic or photoheterotrophic organisms. Here, the photosystems of both processes are described. The main drawback of the photoautotrophic hydrogen production process is oxygen inhibition. The few efficiencies reported on the
International Nuclear Information System (INIS)
Balkan, F.
2005-01-01
A more realistic application of the entropy minimization principle EoEP is presented. This principle dictates uniform local entropy generations along the heat exchanger in order to minimize the total entropy generation rate due only to heat transfer. For a certain heat duty and area of an existing exchanger, this is done by changing the temperatures of one fluid while the temperatures of the other fluid are held constant. Since the heat duty is fixed, the change in the temperatures of the fluid after the change, however, may sometimes cause a drastic change in its flow rate. This may cause considerable changes in the overall heat transfer coefficient (U) and, consequently, in the entropy generation rate. Depending on the choice of the fluid for changing, the new entropy generation rates may be higher or lower than those based on constant U as is the case in papers recently published. So, the classical application of the EoEP principle needs to be modified to achieve more realistic entropy generation rates. In this study, the principle of EoEP with variable U is applied to some cases of heat exchange, and a simple method is presented as a criterion for the proper choice of the fluid to be changed
Engineering microbes for efficient production of chemicals
Gong, Wei; Dole, Sudhanshu; Grabar, Tammy; Collard, Andrew Christopher; Pero, Janice G; Yocum, R Rogers
2015-04-28
This present invention relates to production of chemicals from microorganisms that have been genetically engineered and metabolically evolved. Improvements in chemical production have been established, and particular mutations that lead to those improvements have been identified. Specific examples are given in the identification of mutations that occurred during the metabolic evolution of a bacterial strain genetically engineered to produce succinic acid. This present invention also provides a method for evaluating the industrial applicability of mutations that were selected during the metabolic evolution for increased succinic acid production. This present invention further provides microorganisms engineered to have mutations that are selected during metabolic evolution and contribute to improved production of succinic acid, other organic acids and other chemicals of commercial interest.
Business strategies, profitability and efficiency of production
S. Alarcón; M. Sánchez
2013-01-01
The strategy choices of market-oriented companies are a topic now under wide investigation in the analysis of business performance antecedents. The purpose of this study is to examine the outcomes of the combination of three different organizational strategies (market orientation, innovativeness and entrepreneurial orientation) on business performance indicators. Models using profitability and efficiency indicators are proposed with the specific aim of obtaining a deeper analysis of the relat...
Estimating Production Technical Efficiency of Irvingia Seed (Ogbono ...
African Journals Online (AJOL)
This study estimated the production technical efficiency of irvingia seed (Ogbono) farmers in Nsukka agricultural zone in Enugu State, Nigeria. This is against the backdrop of the importance of efficiency as a factor of productivity in a growing economy like Nigeria where resources are scarce and opportunities for new ...
Maximizing Light Utilization Efficiency and Hydrogen Production in Microalgal Cultures
Energy Technology Data Exchange (ETDEWEB)
Melis, Anastasios [Univ. of California, Berkeley, CA (United States)
2014-12-31
The project addressed the following technical barrier from the Biological Hydrogen Production section of the Fuel Cell Technologies Program Multi-Year Research, Development and Demonstration Plan: Low Sunlight Utilization Efficiency in Photobiological Hydrogen Production is due to a Large Photosystem Chlorophyll Antenna Size in Photosynthetic Microorganisms (Barrier AN: Light Utilization Efficiency).
Intragroup conflicts and efficiency of production group
Directory of Open Access Journals (Sweden)
Sidorenkov A.V.
2017-08-01
Full Text Available Analysis results of relationships of three levels of the conflict (interpersonal, microgroup and group on two types (the job and subject with indicators of subjectively perceived performance and social effectiveness of small groups and informal subgroups are provided. On selection of 42 work groups (N=334 employees it is established that performance efficiency of group according to the experts has inverse relation from all levels and types of the conflict, and by estimates of members of group — from two types of the microgroup conflict. The same type of effectiveness of informal subgroups on one indicator has inverse relation from the group conflict, and on another — from the interpersonal and microgroup conflict. Social effectiveness of group is connected with the interpersonal and group conflict, and informal subgroups are connected with the interpersonal and microgroup conflict. Levels and types of the conflict cause efficiency of group and subgroup not only separately, but also in a combination with each other. Six regression models, four of which display relationships at the same time of several levels and types of the conflict with performance effectiveness of group, and two — with social effectiveness of subgroup are revealed. Mediated and direct relationships of levels and types of the conflict with efficiency of group and subgroup are established.
Multidirectional analysis of technical efficiency for pig production systems
DEFF Research Database (Denmark)
Labajavo, Katarina; Hansson, Helena; Asmild, Mette
2016-01-01
Declining profitability and ongoing structural changes in the pig sector require thorough efficiency analysis of individual production factors. In this study we calculated technical efficiency indices for each input and output using multidirectional efficiency analysis and examined the relationship...... between ‘farm-specific characteristics’ and input and output technical efficiencies by production type (piglet, growing-finishing, finish-to-farrow). The results indicated that advisory services and farm location were not significantly correlated with technical efficiency. Similar results were obtained...... for ‘housing practices’, with the exception of the latest technology such as heated floors in relation to input labour technical efficiency for growing-finishing and finish-to-farrow productions. Use of written instructions for feeding for growing-finishing and finish-to-farrow production and written...
Optimized Kernel Entropy Components.
Izquierdo-Verdiguier, Emma; Laparra, Valero; Jenssen, Robert; Gomez-Chova, Luis; Camps-Valls, Gustau
2017-06-01
This brief addresses two main issues of the standard kernel entropy component analysis (KECA) algorithm: the optimization of the kernel decomposition and the optimization of the Gaussian kernel parameter. KECA roughly reduces to a sorting of the importance of kernel eigenvectors by entropy instead of variance, as in the kernel principal components analysis. In this brief, we propose an extension of the KECA method, named optimized KECA (OKECA), that directly extracts the optimal features retaining most of the data entropy by means of compacting the information in very few features (often in just one or two). The proposed method produces features which have higher expressive power. In particular, it is based on the independent component analysis framework, and introduces an extra rotation to the eigen decomposition, which is optimized via gradient-ascent search. This maximum entropy preservation suggests that OKECA features are more efficient than KECA features for density estimation. In addition, a critical issue in both the methods is the selection of the kernel parameter, since it critically affects the resulting performance. Here, we analyze the most common kernel length-scale selection criteria. The results of both the methods are illustrated in different synthetic and real problems. Results show that OKECA returns projections with more expressive power than KECA, the most successful rule for estimating the kernel parameter is based on maximum likelihood, and OKECA is more robust to the selection of the length-scale parameter in kernel density estimation.
Misuse of thermodynamic entropy in economics
International Nuclear Information System (INIS)
Kovalev, Andrey V.
2016-01-01
The direct relationship between thermodynamic entropy and economic scarcity is only valid for a thermodynamically isolated economy. References to the second law of thermodynamics in economics within the context of scarcity ignore the fact that the earth is not an isolated system. The earth interacts with external sources and sinks of entropy and the resulting total entropy fluctuates around a constant. Even if the mankind finally proves unable to recycle industrial waste and close the technological cycle, the economic disruption caused by the depletion of natural resources may happen while the total thermodynamic entropy of the ecosystem remains essentially at the present level, because the transfer of chemically refined products may not increase significantly the total entropy, but it may decrease their recyclability. The inutility of industrial waste is not connected with its entropy, which may be exemplified with the case of alumina production. The case also demonstrates that industrially generated entropy is discharged into surroundings without being accumulated in ‘thermodynamically unavailable matter’. Material entropy, as a measure of complexity and economic dispersal of resources, can be a recyclability metric, but it is not a thermodynamic parameter, and its growth is not equivalent to the growth of thermodynamic entropy. - Highlights: • Entropy cannot be used as a measure of economic scarcity. • There is no anthropogenic entropy separate from the entropy produced naturally. • Inutility of industrial waste is not connected with its thermodynamic entropy. • Industrially generated entropy may or may not be accumulated in industrial waste. • Recyclability is more important than thermodynamic entropy of a product.
ECONOMIES OF SCALE AND PRODUCTION EFFICIENCY IN ...
African Journals Online (AJOL)
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high rate of population growth of 2.83% (FOS, 1996). The apparent disparity between the rate of food production and demand for food in Nigeria has led to: (i) a food demand-supply gap thus leading to a widening gap between domestic food supply and the total food requirement; (ii) an increased food importation and (iii).
Efficient uranous nitrate production using membrane electrolysis
International Nuclear Information System (INIS)
Zhongwei Yuan; Taihong Yan; Weifang Zheng; Hongying Shuang; Liang Xian; Xiaoyan Bian; Chen Zuo; Chuanbo Li; Zhi Cao
2013-01-01
Electrochemical reduction of uranyl nitrate is a green, simple way to make uranous ion. In order to improve the ratio of uranous ion to the total uranium and maintain high current efficiency, an electrolyser with very thin cathodic and anodic compartment, which were separated by a cation exchange membrane, was setup, and its performance was tested. The effects of various parameters on the reduction were also evaluated. The results show that the apparatus is quite positive. It runs well with 120 mA/cm 2 current density (72 cm 2 cathode, constant current batch operation). U(IV) yield can achieve 93.1 % (500 mL feed, total uranium 199 g/L) after 180 min electrolysis. It was also shown that when U(IV) yield was below 80 %, very high current efficiency was maintained, and there was almost a linear relationship between uranous ion yield and electrolysis time; under the range of experimental conditions, the concentration of uranyl nitrate, hydrazine, and nitric acid had little effect on the reduction. (author)
On unified-entropy characterization of quantum channels
International Nuclear Information System (INIS)
Rastegin, A E
2012-01-01
We consider properties of quantum channels with the use of unified entropies. Extremal unravelings of quantum channel with respect to these entropies are examined. The concept of map entropy is extended in terms of the unified entropies. The map (q, s)-entropy is naturally defined as the unified (q, s)-entropy of a rescaled dynamical matrix of given quantum channel. Inequalities of Fannes type are obtained for introduced entropies in terms of both the trace and Frobenius norms of difference between corresponding dynamical matrices. Additivity properties of introduced map entropies are discussed. The known inequality of Lindblad with the entropy exchange is generalized to many of the unified entropies. For the tensor product of a pair of quantum channels, we derive a two-sided estimate on the output entropy of a maximally entangled input state. (paper)
Determination of Energy Use Efficiency of Sesame Production
BARAN, Mehmet Firat
2018-01-01
In this research it was aimed to determine an energy use efficiency of sesame production in Şanlıurfa province, during the production season of 2015. In order to determine the energy use efficiency of sesame production, trials and measurement were performed in sesame farm in the Bozova district of Şanlıurfa province. As energy inputs, human labour energy, machinery energy, chemical fertilizers energy, irrigation water energy, chemicals energy, diesel fuel energy and seed energy as were calcul...
Entropy-based financial asset pricing.
Directory of Open Access Journals (Sweden)
Mihály Ormos
Full Text Available We investigate entropy as a financial risk measure. Entropy explains the equity premium of securities and portfolios in a simpler way and, at the same time, with higher explanatory power than the beta parameter of the capital asset pricing model. For asset pricing we define the continuous entropy as an alternative measure of risk. Our results show that entropy decreases in the function of the number of securities involved in a portfolio in a similar way to the standard deviation, and that efficient portfolios are situated on a hyperbola in the expected return-entropy system. For empirical investigation we use daily returns of 150 randomly selected securities for a period of 27 years. Our regression results show that entropy has a higher explanatory power for the expected return than the capital asset pricing model beta. Furthermore we show the time varying behavior of the beta along with entropy.
Entropy-based financial asset pricing.
Ormos, Mihály; Zibriczky, Dávid
2014-01-01
We investigate entropy as a financial risk measure. Entropy explains the equity premium of securities and portfolios in a simpler way and, at the same time, with higher explanatory power than the beta parameter of the capital asset pricing model. For asset pricing we define the continuous entropy as an alternative measure of risk. Our results show that entropy decreases in the function of the number of securities involved in a portfolio in a similar way to the standard deviation, and that efficient portfolios are situated on a hyperbola in the expected return-entropy system. For empirical investigation we use daily returns of 150 randomly selected securities for a period of 27 years. Our regression results show that entropy has a higher explanatory power for the expected return than the capital asset pricing model beta. Furthermore we show the time varying behavior of the beta along with entropy.
Improving radiation use efficiency in greenhouse production systems
Li, Tao
2015-01-01
SUMMARY A large increase in agricultural production is needed to feed the increasing world population with their increasing demand per capita. However, growing competition for arable land, water, energy, and the degradation of the environment impose challenges to improve crop production. Hence agricultural production efficiency needs to increase. Greenhouses provide the possibility to create optimal growth conditions for crops, thereby improving production and product quality. Light is the dr...
The efficiency of aerodynamic force production in Drosophila.
Lehmann, F O
2001-12-01
Total efficiency of aerodynamic force production in insect flight depends on both the efficiency with which flight muscles turn metabolic energy into muscle mechanical power and the efficiency with which this power is converted into aerodynamic flight force by the flapping wings. Total efficiency has been estimated in tethered flying fruit flies Drosophila by modulating their power expenditures in a virtual reality flight simulator while simultaneously measuring stroke kinematics, locomotor performance and metabolic costs. During flight, muscle efficiency increases with increasing flight force production, whereas aerodynamic efficiency of lift production decreases with increasing forces. As a consequence of these opposite trends, total flight efficiency in Drosophila remains approximately constant within the kinematic working range of the flight motor. Total efficiency is broadly independent of different profile power estimates and typically amounts to 2-3%. The animal achieves maximum total efficiency near hovering flight conditions, when the beating wings produce flight forces that are equal to the body weight of the insect. It remains uncertain whether this small advantage in total efficiency during hovering flight was shaped by evolutionary factors or results from functional constraints on both the production of mechanical power by the indirect flight muscles and the unsteady aerodynamic mechanisms in flapping flight.
Technical efficiency of watermelon ( Citrullus lanatus ) production in ...
African Journals Online (AJOL)
This study was designed to measure the level of technical efficiency, its determinants in watermelon (Citrullus lanatus) production and the constraints in the production system in Yewa North Local Government of Ogun State using a stochastic frontier production function. A combination of purposive and random sampling ...
An analysis of the productivity and technical efficiency of smallholder ...
African Journals Online (AJOL)
This study used the stochastic frontier production function to analyse the productivity and technical efficiency of 4 different agricultural production systems in Ethiopia; namely, irrigated seasonal farms on traditional irrigation systems, irrigated seasonal farms on modern communal irrigation systems, rainfed seasonal farms for ...
Improving Farmers' Efficiency in Rice Production In Nigeria: The ...
African Journals Online (AJOL)
This paper assesses the effects of extension services on farmers' efficiency and productivity in rice production in Kano State, Nigeria. Data for the study were collected from 126 rice farmers selected using multi stage sampling technique. Stochastic production frontier function was estimated to ascertain the effects of ...
Production Efficiency of Swamp Rice Production in Cross River ...
African Journals Online (AJOL)
This study compares profit maximization, output optimization and resource use efficiency in ... of two varieties of swamp rice by farmers in Cross River State of Nigeria. ... The result of the finding also shows that small-scale farmers were more ...
Energy productivity and efficiency of wheat farming in Bangladesh
International Nuclear Information System (INIS)
Rahman, Sanzidur; Hasan, M. Kamrul
2014-01-01
Wheat is the second most important cereal crop in Bangladesh and production is highly sensitive to variations in the environment. We estimate productivity and energy efficiency of wheat farming in Bangladesh by applying a stochastic production frontier approach while accounting for the environmental constraints affecting production. Wheat farming is energy efficient with a net energy balance of 20,596 MJ per ha and energy ratio of 2.34. Environmental constraints such as a combination of unsuitable land, weed and pest attack, bad weather, planting delay and infertile soils significantly reduce wheat production and its energy efficiency. Environmental constraints account for a mean energy efficiency of 3 percentage points. Mean technical efficiency is 88% thereby indicating that elimination of inefficiencies can increase wheat energy output by 12%. Farmers' education, access to agricultural information and training in wheat production significantly improves efficiency, whereas events such as a delay in planting and first fertilization significantly reduce it. Policy recommendations include development of varieties that are resistant to environmental constraints and suitable for marginal areas; improvement of wheat farming practices; and investments in education and training of farmers as well as dissemination of information. - Highlights: • Bangladesh wheat farming is energy efficient at 20,596 MJha −1 ; energy ratio 2.34. • Environmental factors significantly influence productivity and energy efficiency. • Environmental factors must be taken into account when estimating wheat productivity. • Government policies must focus on ways of alleviating environmental factors. • Farmers' education, training and information sources increase technical efficiency
Economic efficiency of extensive livestock production in the European Union
Directory of Open Access Journals (Sweden)
Nastić Lana
2017-01-01
Full Text Available Various types of extensive livestock production are present worldwide, primarily in regions where natural resources such as pastures and meadows could be used. Extensive livestock production is common in the EU, as well. Therefore the goal of this research was to establish economic efficiency of extensive livestock production types and to compare their efficiency with some intensive livestock production types. In order to achieve that goal FADN (Farm Accountancy Data Network methodology was used. Source of information was FADN database as well as appropriate sector analysis and publications of European commission. It has been determined that sheep and goat production is competitive with intensive production types (dairy and granivores - pigs and poultry. Cattle production (other than dairy production proved to be economically inefficient due to low output level.
Resource Use Efficiency in Rice Production in Jere Local ...
African Journals Online (AJOL)
acer
Descriptive statistics and production function were used as analytical tools. The result ..... women's active participation in agriculture. The result also .... Poverty Reduction. Through the ... and the Efficiencies of India Farm Using. Panel Data ...
Efficient production of transgenic soybean (Glycine max [L] Merrill ...
African Journals Online (AJOL)
Efficient production of transgenic soybean (Glycine max [L] Merrill) plants mediated via whisker-supersonic (WSS) method. MM Khalafalla, HA El-Shemy, SM Rahman, M Teraishi, H Hasegawa, T Terakawa, M Ishimoto ...
International Nuclear Information System (INIS)
Rau, J.
1993-01-01
In the presence of strong gravitational, electromagnetic or other gauge fields, particle-antiparticle pairs are created out of the vacuum. Creation processes of this type are responsible for, e.g., hadron production in heavy ion collisions or the radiation of black holes. They lead to an increase in entropy, thus contributing to the thermalization of the system under consideration. This suggests that particle creation in strong fields is an irreversible process. Key issues to be addressed are: (1) under which conditions particle creation is indeed irreversible, and how this can be reconciled with the time-reversal invariance of the underlying microscopic dynamics: (ii) if-and if so, how-particle creation can be described within the framework of a theory of nonequilibrium processes: (iii) how the associated entropy is defined; and (iv) how particle creation can be incorporated into a kinetic equation that also accounts for subsequent acceleration and collisions. These issues are studied by means of the projection method. After a comprehensive introduction to that method, it is applied to a simple model from quantum electrodynamics which incorporates acceleration, collisions, and pair creation due to the Schwinger mechanism. For this model, the author obtains: (1) the complete set of time scales, which furnishes a precise mathematical criterion for the irreversibility of particle creation; (2) the associated relevant entropy to which the H-theorem applies; and (3) a generalization of the quantum Boltzmann equation which includes a source term derived from first principles
An Empirical Study of Strategic Positioning and Production Efficiency
Hsihui Chang; Guy D. Fernando; Arindam Tripathy
2015-01-01
We examine the relationship between strategic positioning of firms and their production efficiency. Firms with competitive advantages based on either cost leadership or differentiation are able to outperform their competitors. Firms pursuing a cost leadership strategy seek to be the lowest cost producer, primarily by minimizing inputs for a given level of output, thus concentrating on increasing the efficiency of their production processes. On the other hand, firms that pursue a differentiat...
Productive efficiency of tea industry: A stochastic frontier approach ...
African Journals Online (AJOL)
In an economy where recourses are scarce and opportunities for a new technology are lacking, studies will be able to show the possibility of raising productivity by improving the industry's efficiency. This study attempts to measure the status of technical efficiency of tea-producing industry for panel data in Bangladesh using ...
Implications of energy efficiency measures in wheat production
DEFF Research Database (Denmark)
Meyer-Aurich, Andreas; Ziegler, T.; Scholz, L.
The economic and environmental effect of energy saving measures were analyzed for a typical wheat production system in Germany. The introduction of precision farming, reduced nitrogen fertilization and improved crop drying technologies proved to be efficient measures for enhancing energy efficiency...
Excess Entropy and Diffusivity
Indian Academy of Sciences (India)
First page Back Continue Last page Graphics. Excess Entropy and Diffusivity. Excess entropy scaling of diffusivity (Rosenfeld,1977). Analogous relationships also exist for viscosity and thermal conductivity.
Environmental assessment for the Consumer Products Efficiency Standards program
Energy Technology Data Exchange (ETDEWEB)
1980-05-23
The Energy Policy and Conservation Act of 1975 as amended by the National Energy Conservation Policy Act of 1978, requires the DOE to prescribe energy efficiency standards for thirteen consumer products. The Consumer Products Efficiency Standards (CPES) program covers the following products: refrigerators and refrigerator-freezers; freezers;clothes dryers;water heaters; room air conditioners; home heating equipment (not including furnaces); kitchen ranges and ovens; central air conditioners (cooling and heat pumps); furnaces; dishwashers; television sets; clothes washers; and humidifiers and dehumidifiers. DOE is proposing two sets of standards for all thirteen consumer products: intermediate standards to become effective in 1981 for the first nine products and in 1982 for the second four products, and final standards to become effective in 1986 and 1987, respectively. The final standards are more restrictive than the intermediate standards and will provide manufacturers with the maximum time permitted under the Act to plan and develop extensive new lines of efficient consumer products. The final standards proposed by DOE require the maximum improvements in efficiency which are technologically feasible and economically justified, as required by Section 325(c) of EPCA. The thirteen consumer products account for approximately 90% of all the energy consumed in the nation's residences, or more than 20% of the nation's energy needs. Increases in the energy efficiency of these consumer products can help to narrow the gap between the nation's increasing demand for energy and decreasing supplies of domestic oil and natural gas. Improvements in the efficiency of consumer products can thus help to solve the nation's energy crisis.
Explaining the entropy concept and entropy components
Directory of Open Access Journals (Sweden)
Marko Popovic
2018-04-01
Full Text Available Total entropy of a thermodynamic system consists of two components: thermal entropy due to energy, and residual entropy due to molecular orientation. In this article, a three-step method for explaining entropy is suggested. Step one is to use a classical method to introduce thermal entropy STM as a function of temperature T and heat capacity at constant pressure Cp: STM = ∫(Cp/T dT. Thermal entropy is the entropy due to uncertainty in motion of molecules and vanishes at absolute zero (zero-point energy state. It is also the measure of useless thermal energy that cannot be converted into useful work. The next step is to introduce residual entropy S0 as a function of the number of molecules N and the number of distinct orientations available to them in a crystal m: S0 = N kB ln m, where kB is the Boltzmann constant. Residual entropy quantifies the uncertainty in molecular orientation. Residual entropy, unlike thermal entropy, is independent of temperature and remains present at absolute zero. The third step is to show that thermal entropy and residual entropy add up to the total entropy of a thermodynamic system S: S = S0 + STM. This method of explanation should result in a better comprehension of residual entropy and thermal entropy, as well as of their similarities and differences. The new method was tested in teaching at Faculty of Chemistry University of Belgrade, Serbia. The results of the test show that the new method has a potential to improve the quality of teaching.
An Efficiency Model For Hydrogen Production In A Pressurized Electrolyzer
Energy Technology Data Exchange (ETDEWEB)
Smoglie, Cecilia; Lauretta, Ricardo
2010-09-15
The use of Hydrogen as clean fuel at a world wide scale requires the development of simple, safe and efficient production and storage technologies. In this work, a methodology is proposed to produce Hydrogen and Oxygen in a self pressurized electrolyzer connected to separate containers that store each of these gases. A mathematical model for Hydrogen production efficiency is proposed to evaluate how such efficiency is affected by parasitic currents in the electrolytic solution. Experimental set-up and results for an electrolyzer are also presented. Comparison of empirical and analytical results shows good agreement.
Singbo, Alphonse G.; Lansink, Alfons Oude; Emvalomatis, Grigorios
2015-01-01
This paper analyzes technical efficiency and the value of the marginal product of productive inputs vis-a-vis pesticide use to measure allocative efficiency of pesticide use along productive inputs. We employ the data envelopment analysis framework and marginal cost techniques to estimate
Technical efficiency in pig production in Akwa Ibom State, Nigeria ...
African Journals Online (AJOL)
This study was designed to measure the level of technical efficiency and its determinants in pig production in Akwa Ibom State, Nigeria using a stochastic frontier production function. Multistage random sampling technique was used to select 60 pig farms from which input-output data were collected in 2004. The estimated ...
Maximum herd efficiency in meat production I. Optima for slaughter ...
African Journals Online (AJOL)
Profit rate for a meat production enterprise can be decomposedinto the unit price for meat and herd ... supply and demand, whereas breeding improvement is gen- ... Herd efficiency is total live mass for slaughter divided by costs .... tenance and above-maintenance components by Dickerson, and ..... Growth and productivity.
Endogeneity Corrected Stochastic Production Frontier and Technical Efficiency
Shee, A.; Stefanou, S.E.
2015-01-01
A major econometric issue in estimating production parameters and technical efficiency is the possibility that some forces influencing production are only observed by the firm and not by the econometrician. Not only can this misspecification lead to a biased inference on the output elasticity of
International benchmaking: Supplying the information for product efficiency policy makers
Siderius, H.P.; Jeffcott, S.; Blok, K.
2012-01-01
In the development of effective product efficiency policy, the critical element for policy makers is comprehensive, independent information. However, easily accessible, reliable information on the energy performance of products and policies is often scarce within a particular market, and rarer still
Cambridge journals blog: Improving feed efficiency in dairy production
Because the cost of feeding animals is one of the greatest expenses in dairy production (40-60% of production costs), research focused on ways to identify and select for animals that are the most efficient at converting feed into milk has greatly expanded during the last decade. The animal Article o...
Towards a more efficient energy use in photovoltaic powered products
Kan, S.Y.; Strijk, R.
2006-01-01
This paper analyzes the energy saving and power management solutions necessary to improve the energy consumption efficiency in photovoltaic powered products. Important in the design of such products is not only the energy supply optimization required to deliver the actual energy to fulfil their
POSSIBILITIES OF INCREASING EFFICIENCY WITHIN SERIAL PRODUCTION MANAGEMENT
Directory of Open Access Journals (Sweden)
CODRUŢA DURA
2010-01-01
Full Text Available Under the impact of transition to the new post-industrial society, massproduction recently faced the most numerous difficulties. They are caused by turbulences in theexternal environment in which companies operate, manifested in particular by enhancing thedynamism of markets and by deep changes in the structure of consumers’ demands. In thiscontext, specialized literature records the concerns for increasing the efficiency and flexibilityof products, elements involving radical changes of management and manufacturingtechnologies methods. Given these issues, the paper approaches two separate ways to improvethe management of serial production: increasing economic efficiency by optimizing the size ofbatches and flexible production systems by implementing techniques to reduce the change-overtime.
Environmental assessment. Energy efficiency standards for consumer products
Energy Technology Data Exchange (ETDEWEB)
McSwain, Berah
1980-06-01
The Energy Policy and Conservation Act of 1975 requires DOE to prescribe energy efficiency standards for 13 consumer products. The Consumer Products Efficiency Standards (CPES) program covers: refrigerators and refrigerator-freezers, freezers, clothes dryers, water heaters, room air conditioners, home heating equipment, kitchen ranges and ovens, central air conditioners (cooling and heat pumps), furnaces, dishwashers, television sets, clothes washers, and humidifiers and dehumidifiers. This Environmental Assessment evaluates the potential environmental and socioeconomic impacts expected as a result of setting efficiency standards for all of the consumer products covered by the CPES program. DOE has proposed standards for eight of the products covered by the Program in a Notice of Proposed Rulemaking (NOPR). DOE expects to propose standards for home heating equipment, central air conditioners (heat pumps only), dishwashers, television sets, clothes washers, and humidifiers and dehumidifiers in 1981. No significant adverse environmental or socioeconomic impacts have been found to result from instituting the CPES.
International Nuclear Information System (INIS)
Chen, Yong; Ge, Hao; Xiong, Jie; Xu, Lihu
2016-01-01
Fluctuation theorem is one of the major achievements in the field of nonequilibrium statistical mechanics during the past two decades. There exist very few results for steady-state fluctuation theorem of sample entropy production rate in terms of large deviation principle for diffusion processes due to the technical difficulties. Here we give a proof for the steady-state fluctuation theorem of a diffusion process in magnetic fields, with explicit expressions of the free energy function and rate function. The proof is based on the Karhunen-Loève expansion of complex-valued Ornstein-Uhlenbeck process.
Efficiency and Import Penetration on the Productivity of Textile Industry and Textile Products
Directory of Open Access Journals (Sweden)
Catur Basuki Rakhmawan
2012-12-01
Full Text Available Although textile industry and textile products belong to the strategic sub-sector of manufacturing industry in Indonesia, they are facing problems on the availability of energy, old production machines, and the flooding of imported products into the domestic market. This study is aimed to analyze the efficiency and productivity as performance indicators and how the efficiency and import penetration affect the productivity of textile industry and textile products. The methods of data analysis used in this research are divided in two phases. The first phase, the non-metric approach of Data Envelopment Analysis (DEA is applied to measure the efficiency and productivity. Secondly, the fixed effect model of econometric regression approach is used to find out the effects of efficiency and import penetration on the productivity of textile industry and textile products. The result shows that the average level of efficiency of textile industry and textile products during the period of 2004 – 2008 is about 40 percent with a growth rate of average productivity increases 2.4 percent. Whereas, the econometric estimation results indicate that the increase of efficiency will positively and significantly affect the productivity of textile industry and textile products. On the other hand, the increase of import penetration will negatively affect the productivity of this industry.
Efficiency and Import Penetrationon the Productivity of Textile Industry and Textile Products
Directory of Open Access Journals (Sweden)
Catur Basuki Rakhmawan
2012-12-01
Full Text Available Although textile industry and textile products belong to the strategic sub-sector of manufacturing industry in Indonesia, they are facing problems on the availability of energy, old production machines, and the flooding of imported products into the domestic market. This study is aimed to analyze the efficiency and productivity as performance indicators and how the efficiency and import penetration affect the productivity of textile industry and textile products. The methods of data analysis used in this research are divided in two phases. The first phase, the non-metric approach of Data Envelopment Analysis (DEA is applied to measure the efficiency and productivity. Secondly, the fixed effect model of econometric regression approach is used to find out the effects of efficiency and import penetration on the productivity of textile industry and textile products. The result shows that the ave-rage level of efficiency of textile industry and textile products during the period of 2004 – 2008 is about 40 percent with a growth rate of average productivity increases 2.4 percent. Whereas, the econometric estimation results indicate that the increase of efficiency will positively and significantly affect the productivity of textile industry and textile products. On the other hand, the increase of import penetration will negatively affect the productivity of this industry.
Entropy of the system formed in heavy ion collision
International Nuclear Information System (INIS)
Gudima, K.K.; Schulz, H.; Toneev, V.D.
1985-01-01
In frames of a cascade model the entropy evolution in a system producted in heavy ion collisions is investigated. Entropy calculation is based on smoothing of the distribution function over the momentum space by the temperature field introduction. The resulting entropy per one nucleon is shown to be rather sensitive to phase space subdivision into cells at the stage of free scattering of reaction products. Compared to recent experimental results for specific entropy values inferred from the composite particle yield of 4π measurements, it is found that cascade calculations do not favour some particular entropy model treatments and suggest smaller entropy values than following from consideration within equilibrium statistics
Thurner, Stefan; Corominas-Murtra, Bernat; Hanel, Rudolf
2017-09-01
There are at least three distinct ways to conceptualize entropy: entropy as an extensive thermodynamic quantity of physical systems (Clausius, Boltzmann, Gibbs), entropy as a measure for information production of ergodic sources (Shannon), and entropy as a means for statistical inference on multinomial processes (Jaynes maximum entropy principle). Even though these notions represent fundamentally different concepts, the functional form of the entropy for thermodynamic systems in equilibrium, for ergodic sources in information theory, and for independent sampling processes in statistical systems, is degenerate, H (p ) =-∑ipilogpi . For many complex systems, which are typically history-dependent, nonergodic, and nonmultinomial, this is no longer the case. Here we show that for such processes, the three entropy concepts lead to different functional forms of entropy, which we will refer to as SEXT for extensive entropy, SIT for the source information rate in information theory, and SMEP for the entropy functional that appears in the so-called maximum entropy principle, which characterizes the most likely observable distribution functions of a system. We explicitly compute these three entropy functionals for three concrete examples: for Pólya urn processes, which are simple self-reinforcing processes, for sample-space-reducing (SSR) processes, which are simple history dependent processes that are associated with power-law statistics, and finally for multinomial mixture processes.
Efficiency of dairy production on a family farm
Directory of Open Access Journals (Sweden)
Zoran Grgić
2002-01-01
Full Text Available This paper presents the evaluation of economic efficiency of dairyproduction on a family farm with 14 dairy cows in the breeding stock, and with average production from 3.206 to 3.407 lit. of milk annually. On the basis of survey data for three-year period from 1998 to 2000, economic indicators were calculated, as well as the cost price of milk, income and the revenue of total production and per production head. In the family farm with an average annual sale from 2.827 to 2.972 lit. of milk per head, total revenue has been realized from 44.884 to 47.695 kuna and the profit from 606 to 8.515 kuna. Revenues per production head were from 5.655 to 6.495 kuna and the profitfrom 177 to 726 kuna. The milk cost price in the analyzed period was 1.71, 1.66 and 1.69 kn. per lit, and the profit per liter of milk was 0.06, and 0.21 kn. Basic economic indicators point out on efficiency of dairy production for the investigated farm on the stated production level. The biggest influence on the dairy production efficiency on the farm, regarding the cost price structure, has been registered from the costs of fodder production, while the favorable parity of the cost price and producer-sale price of milk determines the increase in dairy production efficiency and income from dairy production in the analyzed period.
Efficient protein production by yeast requires global tuning of metabolism
DEFF Research Database (Denmark)
Huang, Mingtao; Bao, Jichen; Hallstrom, Bjorn M.
2017-01-01
The biotech industry relies on cell factories for production of pharmaceutical proteins, of which several are among the top-selling medicines. There is, therefore, considerable interest in improving the efficiency of protein production by cell factories. Protein secretion involves numerous...... intracellular processes with many underlying mechanisms still remaining unclear. Here, we use RNA-seq to study the genome-wide transcriptional response to protein secretion in mutant yeast strains. We find that many cellular processes have to be attuned to support efficient protein secretion. In particular...... that by tuning metabolism cells are able to efficiently secrete recombinant proteins. Our findings provide increased understanding of which cellular regulations and pathways are associated with efficient protein secretion....
Efficient promotion of electricity production from offshore wind
International Nuclear Information System (INIS)
Panzer, Christian; Auer, Hans; Lettner, Georg
2014-01-01
Efficient promotion of electricity production from offshore wind stands in dynamic relationship with various influence factors, the most important of which are promotion instruments, topographic givens, regulation of grid connection, and supraregional market integration concepts. Using three case studies from different countries to highlight national differences in the promotion of offshore wind power plants the present analysis points out ways of improving the efficiency of promotion instruments.
SpatEntropy: Spatial Entropy Measures in R
Altieri, Linda; Cocchi, Daniela; Roli, Giulia
2018-01-01
This article illustrates how to measure the heterogeneity of spatial data presenting a finite number of categories via computation of spatial entropy. The R package SpatEntropy contains functions for the computation of entropy and spatial entropy measures. The extension to spatial entropy measures is a unique feature of SpatEntropy. In addition to the traditional version of Shannon's entropy, the package includes Batty's spatial entropy, O'Neill's entropy, Li and Reynolds' contagion index, Ka...
What factors affect the productivity and efficiency of physician practices?
Sunshine, Jonathan H; Hughes, Danny R; Meghea, Cristian; Bhargavan, Mythreyi
2010-02-01
Increasing the productivity and efficiency of physician practices could help relieve the rapid growth of US healthcare costs and the expected physician shortage. Radiology practices are an attractive specific focus for research on practices' productivity and efficiency because they are home to many purportedly productivity-enhancing operational technologies. This affords an opportunity to study the effect of production technology on physicians' output. As well, radiology is a leader in the general movement of physicians out of very small practices. And imaging is by the fastest-growing category of physician expenditure. Using data from 2003 to 2007 surveys of radiologists, we estimate a stochastic frontier model to study the effects of practice characteristics, such as work hours, practice size, and output mix, and technologies used in work production, on practices' productivity and efficiency. At the mean, the elasticities of output with respect to practice size and annual hours worked per full-time physician were 0.73 and 0.51, respectively. Some production technologies increase productivity by 15% to 20%; others generate no increase. Using "nighthawks"--ie, contracting out after-hours work to external firms that consolidate workflow--significantly increases practice efficiency. The general US trend toward larger practice size is unlikely to relieve cost or physician shortage pressures. The actual effect of purportedly productivity-enhancing operational technologies needs to be carefully evaluated before they are widely adopted. As the recently-developed innovations of nighthawks and hospitalists show, practices should give more attention to a possible choice to "buy," rather than "make," part of their output.
Biodiversity influences plant productivity through niche-efficiency.
Liang, Jingjing; Zhou, Mo; Tobin, Patrick C; McGuire, A David; Reich, Peter B
2015-05-05
The loss of biodiversity is threatening ecosystem productivity and services worldwide, spurring efforts to quantify its effects on the functioning of natural ecosystems. Previous research has focused on the positive role of biodiversity on resource acquisition (i.e., niche complementarity), but a lack of study on resource utilization efficiency, a link between resource and productivity, has rendered it difficult to quantify the biodiversity-ecosystem functioning relationship. Here we demonstrate that biodiversity loss reduces plant productivity, other things held constant, through theory, empirical evidence, and simulations under gradually relaxed assumptions. We developed a theoretical model named niche-efficiency to integrate niche complementarity and a heretofore-ignored mechanism of diminishing marginal productivity in quantifying the effects of biodiversity loss on plant productivity. Based on niche-efficiency, we created a relative productivity metric and a productivity impact index (PII) to assist in biological conservation and resource management. Relative productivity provides a standardized measure of the influence of biodiversity on individual productivity, and PII is a functionally based taxonomic index to assess individual species' inherent value in maintaining current ecosystem productivity. Empirical evidence from the Alaska boreal forest suggests that every 1% reduction in overall plant diversity could render an average of 0.23% decline in individual tree productivity. Out of the 283 plant species of the region, we found that large woody plants generally have greater PII values than other species. This theoretical model would facilitate the integration of biological conservation in the international campaign against several pressing global issues involving energy use, climate change, and poverty.
Biodiversity influences plant productivity through niche–efficiency
Liang, Jingjing; Zhou, Mo; Tobin, Patrick C.; McGuire, A. David; Reich, Peter B.
2015-01-01
The loss of biodiversity is threatening ecosystem productivity and services worldwide, spurring efforts to quantify its effects on the functioning of natural ecosystems. Previous research has focused on the positive role of biodiversity on resource acquisition (i.e., niche complementarity), but a lack of study on resource utilization efficiency, a link between resource and productivity, has rendered it difficult to quantify the biodiversity–ecosystem functioning relationship. Here we demonstrate that biodiversity loss reduces plant productivity, other things held constant, through theory, empirical evidence, and simulations under gradually relaxed assumptions. We developed a theoretical model named niche–efficiency to integrate niche complementarity and a heretofore-ignored mechanism of diminishing marginal productivity in quantifying the effects of biodiversity loss on plant productivity. Based on niche–efficiency, we created a relative productivity metric and a productivity impact index (PII) to assist in biological conservation and resource management. Relative productivity provides a standardized measure of the influence of biodiversity on individual productivity, and PII is a functionally based taxonomic index to assess individual species’ inherent value in maintaining current ecosystem productivity. Empirical evidence from the Alaska boreal forest suggests that every 1% reduction in overall plant diversity could render an average of 0.23% decline in individual tree productivity. Out of the 283 plant species of the region, we found that large woody plants generally have greater PII values than other species. This theoretical model would facilitate the integration of biological conservation in the international campaign against several pressing global issues involving energy use, climate change, and poverty.
Biodiversity influences plant productivity through niche–efficiency
Liang, Jingjing; Zhou, Mo; Tobin, Patrick C.; McGuire, A. David; Reich, Peter B.
2015-01-01
The loss of biodiversity is threatening ecosystem productivity and services worldwide, spurring efforts to quantify its effects on the functioning of natural ecosystems. Previous research has focused on the positive role of biodiversity on resource acquisition (i.e., niche complementarity), but a lack of study on resource utilization efficiency, a link between resource and productivity, has rendered it difficult to quantify the biodiversity–ecosystem functioning relationship. Here we demonstrate that biodiversity loss reduces plant productivity, other things held constant, through theory, empirical evidence, and simulations under gradually relaxed assumptions. We developed a theoretical model named niche–efficiency to integrate niche complementarity and a heretofore-ignored mechanism of diminishing marginal productivity in quantifying the effects of biodiversity loss on plant productivity. Based on niche–efficiency, we created a relative productivity metric and a productivity impact index (PII) to assist in biological conservation and resource management. Relative productivity provides a standardized measure of the influence of biodiversity on individual productivity, and PII is a functionally based taxonomic index to assess individual species’ inherent value in maintaining current ecosystem productivity. Empirical evidence from the Alaska boreal forest suggests that every 1% reduction in overall plant diversity could render an average of 0.23% decline in individual tree productivity. Out of the 283 plant species of the region, we found that large woody plants generally have greater PII values than other species. This theoretical model would facilitate the integration of biological conservation in the international campaign against several pressing global issues involving energy use, climate change, and poverty. PMID:25901325
Dewar, R
2003-01-01
Jaynes' information theory formalism of statistical mechanics is applied to the stationary states of open, non-equilibrium systems. First, it is shown that the probability distribution p subGAMMA of the underlying microscopic phase space trajectories GAMMA over a time interval of length tau satisfies p subGAMMA propor to exp(tau sigma subGAMMA/2k sub B) where sigma subGAMMA is the time-averaged rate of entropy production of GAMMA. Three consequences of this result are then derived: (1) the fluctuation theorem, which describes the exponentially declining probability of deviations from the second law of thermodynamics as tau -> infinity; (2) the selection principle of maximum entropy production for non-equilibrium stationary states, empirical support for which has been found in studies of phenomena as diverse as the Earth's climate and crystal growth morphology; and (3) the emergence of self-organized criticality for flux-driven systems in the slowly-driven limit. The explanation of these results on general inf...
Tran, Hai L; Lexa, Katrina W; Julien, Olivier; Young, Travis S; Walsh, Christopher T; Jacobson, Matthew P; Wells, James A
2017-02-22
Macrocycles are appealing drug candidates due to their high affinity, specificity, and favorable pharmacological properties. In this study, we explored the effects of chemical modifications to a natural product macrocycle upon its activity, 3D geometry, and conformational entropy. We chose thiocillin as a model system, a thiopeptide in the ribosomally encoded family of natural products that exhibits potent antimicrobial effects against Gram-positive bacteria. Since thiocillin is derived from a genetically encoded peptide scaffold, site-directed mutagenesis allows for rapid generation of analogues. To understand thiocillin's structure-activity relationship, we generated a site-saturation mutagenesis library covering each position along thiocillin's macrocyclic ring. We report the identification of eight unique compounds more potent than wild-type thiocillin, the best having an 8-fold improvement in potency. Computational modeling of thiocillin's macrocyclic structure revealed a striking requirement for a low-entropy macrocycle for activity. The populated ensembles of the active mutants showed a rigid structure with few adoptable conformations while inactive mutants showed a more flexible macrocycle which is unfavorable for binding. This finding highlights the importance of macrocyclization in combination with rigidifying post-translational modifications to achieve high-potency binding.
The Efficiency of Damage Production in Silicon Carbide
International Nuclear Information System (INIS)
Weber, William J.; Gao, Fei; Devanathan, Ram; Jiang, Weilin
2004-01-01
Molecular dynamics simulations are used to study the statistics of damage production in 3C-SiC due to C, Si and Au primary knock-on atoms (PKAs) over energies from 0.25 to 50 keV. In order to account for the different displacement energies on the Si and C sublattices and accurately assess the damage efficiency, a modified version of the SRIM (Stopping and Range of Ions in Matter) code, with the electronic stopping turned off to duplicate the molecular dynamics conditions, was used to calculate the statistics of damage production for the same PKAs over the energy range from 0.1 to 400 keV under the binary collision approximation using threshold displacement energies of 20 and 35 eV for C and Si, respectively. Using the modified SRIM predictions as a reference, the efficiencies of total damage production are determined for C, Si and Au PKAs as functions of energy. The efficiency for production of C displacements is similar for all PKAs; however, C PKAs have a much lower efficiency for producing stable Si displacements than Si and Au PKAs, which leads to a much higher ratio of C to Si displacements for C PKAs. These results are consistent with the experimental damage production behavior observed in SiC irradiated with C, Si and Au ions at 150 K
The efficiency of damage production in silicon carbide
International Nuclear Information System (INIS)
Weber, W.J.; Gao, F.; Devanathan, R.; Jiang, W.
2004-01-01
Molecular dynamics (MD) simulations are used to study the statistics of damage production in 3C-SiC due to C, Si and Au primary knock-on atoms (PKAs) over energies from 0.25 to 50 keV. In order to account for the different displacement energies on the Si and C sublattices and accurately assess the damage efficiency, a modified version of the SRIM (stopping and range of ions in matter) code, with the electronic stopping turned off to duplicate the MD conditions, was used to calculate the statistics of damage production for the same PKAs over the energy range from 0.1 to 400 keV under the binary collision approximation using threshold displacement energies of 20 and 35 eV for C and Si, respectively. Using the modified SRIM predictions as a reference, the efficiencies of total damage production are determined for C, Si and Au PKAs as functions of energy. The efficiency for production of C displacements is similar for all PKAs; however, C PKAs have a much lower efficiency for producing stable Si displacements than Si and Au PKAs, which leads to a much higher ratio of C to Si displacements for C PKAs. These results are consistent with the experimental damage production behavior observed in SiC irradiated with C, Si and Au ions at 150 K
Energy efficiency improvements in ammonia production--perspectives and uncertainties
International Nuclear Information System (INIS)
Rafiqul, Islam; Weber, Christoph; Lehmann, Bianca; Voss, Alfred
2005-01-01
The paper discusses the energy consumption and energy saving potential for a major energy-intensive product in the chemical industry-ammonia, based on technologies currently in use and possible process improvements. The paper consists of four parts. In the first part, mainly references to various ammonia production technologies are given. Energy consumption, emissions and saving potentials are discussed in the second part. Thereby, the situation in Europe, the US and India is highlighted and various data sources are compared. In the third part of the paper, a novel approach for modeling energy efficiency improvements is described that accounts for uncertainties and unobserved heterogeneity in the production processes. Besides new investments, revamping investments are also included in the modeling and the development of the production stock is accounted for. Finally, in the fourth part, this approach is applied to the modeling of energy efficiency improvements and CO 2 emission reductions in ammonia production. Thereby, considerable improvements in specific energy use and CO 2 emissions are found in the reference scenario, yet under the assumption of high oil and gas prices, a partial switch to coal based technologies is expected which lowers notably the CO 2 efficiency. Introduction of a CO 2 penalty under a certificate trading or other regime is on contrary found to foster energy efficiency and the use of low carbon technologies
Evaluation of the efficiency of alternative enzyme production technologies
DEFF Research Database (Denmark)
Albæk, Mads Orla
Enzymes are used in an increasing number of industries. The application of enzymes is extending into the production of lignocellulosic ethanol in processes that economically can compete with fossil fuels. Since lignocellulosic ethanol is based on renewable resources it will have a positive impact...... production of cellulases and hemi-cellulases. The aim of the thesiswas to use modeling tools to identify alternative technologies that have higher energy or raw material efficiency than the current technology. The enzyme production by T. reesei was conducted as an aerobic fed-batch fermentation. The process...... of the uncertainty and sensitivity of the model indicated the biological parameters to be responsible for most of the model uncertainty. A number of alternative fermentation technologies for enzyme production were identified in the open literature. Their mass transfer capabilities and their energy efficiencies were...
On Thermodynamic Interpretation of Transfer Entropy
Directory of Open Access Journals (Sweden)
Don C. Price
2013-02-01
Full Text Available We propose a thermodynamic interpretation of transfer entropy near equilibrium, using a specialised Boltzmann’s principle. The approach relates conditional probabilities to the probabilities of the corresponding state transitions. This in turn characterises transfer entropy as a difference of two entropy rates: the rate for a resultant transition and another rate for a possibly irreversible transition within the system affected by an additional source. We then show that this difference, the local transfer entropy, is proportional to the external entropy production, possibly due to irreversibility. Near equilibrium, transfer entropy is also interpreted as the difference in equilibrium stabilities with respect to two scenarios: a default case and the case with an additional source. Finally, we demonstrated that such a thermodynamic treatment is not applicable to information flow, a measure of causal effect.
Improved production efficiency in cattle to reduce their carbon ...
African Journals Online (AJOL)
p2492989
Keywords: Methane, global warming, greenhouse gas, crossbreeding, residual feed intake, feed efficiency. #Corresponding ... improved production per constant unit, crossbreeding and selection for residual feed intake. ... convert such a measure into kg calf produced per kg CO2 equivalent (CH4 can be converted to a CO2.
Efficiency, Effectiveness and Productivity: The Abstract Measures of ...
African Journals Online (AJOL)
This paper makes a case for reviving the system. Efficiency, effectiveness and productivity which are all quality indices are carefully discussed and synthesized into management techniques that will create in the staff and management officials the culture of excellent performance in our higher educational system.
Resource Use Efficiency in Rice Production in Jere Local ...
African Journals Online (AJOL)
The study was carried-out on resource use efficiency in rice production in Jere Local Government Area of Borno State, Nigeria. Data were obtained using structured questionnaire. Five (5) wards were purposely selected out of the twelve (12) wards to reflect areas where rice is mainly grown. A total of 100 respondents were ...
Analysis of economic efficiency in cocoa production in Ghana ...
African Journals Online (AJOL)
The main purpose of this study was to analyze the economic efficiency of resource utilization in cocoa production of the cocoa farmers in Ghana to provide information for effective application and management of farm inputs on cocoa farms and policy recommendation. A random sample of 300 farmers in the Eastern, Ashanti ...
Growth, light interception, radiation use efficiency and productivity of ...
African Journals Online (AJOL)
The purpose of this study was to assess the influence of sowing date on growth, light interception, radiation use efficiency and productivity of mungbean cultivars. The experiment comprised four sowing dates at ten days interval, viz. 08, 18, 28 July and 07 August 2006 and two cultivars, viz. Gofa local and MH-97-6.
Economic efficiency of maize production in Yola North Local ...
African Journals Online (AJOL)
Similarly, the efficiency ratio computed showed that land, seed and fertilizer had MVP/MFC ratio greater than unity implying that the inputs were underutilized and output could be increased by increasing the levels of their utilization. The elasticity of production was greater than 1.00 which implied increasing return to scale.
Informatics in radiology: Efficiency metrics for imaging device productivity.
Hu, Mengqi; Pavlicek, William; Liu, Patrick T; Zhang, Muhong; Langer, Steve G; Wang, Shanshan; Place, Vicki; Miranda, Rafael; Wu, Teresa Tong
2011-01-01
Acute awareness of the costs associated with medical imaging equipment is an ever-present aspect of the current healthcare debate. However, the monitoring of productivity associated with expensive imaging devices is likely to be labor intensive, relies on summary statistics, and lacks accepted and standardized benchmarks of efficiency. In the context of the general Six Sigma DMAIC (design, measure, analyze, improve, and control) process, a World Wide Web-based productivity tool called the Imaging Exam Time Monitor was developed to accurately and remotely monitor imaging efficiency with use of Digital Imaging and Communications in Medicine (DICOM) combined with a picture archiving and communication system. Five device efficiency metrics-examination duration, table utilization, interpatient time, appointment interval time, and interseries time-were derived from DICOM values. These metrics allow the standardized measurement of productivity, to facilitate the comparative evaluation of imaging equipment use and ongoing efforts to improve efficiency. A relational database was constructed to store patient imaging data, along with device- and examination-related data. The database provides full access to ad hoc queries and can automatically generate detailed reports for administrative and business use, thereby allowing staff to monitor data for trends and to better identify possible changes that could lead to improved productivity and reduced costs in association with imaging services. © RSNA, 2011.
Resource Use Efficiency in Sweet Potato Production in Kwara State ...
African Journals Online (AJOL)
This paper examines resource use efficiency in sweet potato production in Offa and Oyun local government areas of Kwara State of Nigeria. Primary data were collected from one hundred sweet potato farmers who were selected from the two local government areas during the 2003/2004 farming season. The data was ...
Efficient Provision of Employment Service Outputs: A Production Frontier Analysis.
Cavin, Edward S.; Stafford, Frank P.
1985-01-01
This article develops a production frontier model for the Employment Service and assesses the relative efficiency of the 51 State Employment Security Agencies in attaining program outcomes close to that frontier. This approach stands in contrast to such established practices as comparing programs to their own previous performance. (Author/CT)
Cost-efficiency of animal welfare in broiler production systems
Gocsik, Éva; Brooshooft, Suzanne D.; Jong, de Ingrid C.; Saatkamp, Helmut W.
2016-01-01
Broiler producers operate in a highly competitive and cost-price driven environment. In addition, in recent years the societal pressure to improve animal welfare (AW) in broiler production systems is increasing. Hence, from an economic and decision making point of view, the cost-efficiency of
Economic efficiency of cocoa production in Ghana | Aneani | Journal ...
African Journals Online (AJOL)
The main purpose of this study was to analyze the economic efficiency of resource utilization in cocoa production among cocoa farmers in Ghana to provide information for effective application and management of farm input on cocoa farms. A random sample of 300 farmers was selected in six cocoa growing districts in ...
Efficiency analysis of hydrogen production methods from biomass
Ptasinski, K.J.
2008-01-01
Abstract: Hydrogen is considered as a universal energy carrier for the future, and biomass has the potential to become a sustainable source of hydrogen. This article presents an efficiency analysis of hydrogen production processes from a variety of biomass feedstocks by a thermochemical method –
Non-parametric analysis of production efficiency of poultry egg ...
African Journals Online (AJOL)
Non-parametric analysis of production efficiency of poultry egg farmers in Delta ... analysis of factors affecting the output of poultry farmers showed that stock ... should be put in place for farmers to learn the best farm practices carried out on the ...
Entropy Generation in a Chemical Reaction
Miranda, E. N.
2010-01-01
Entropy generation in a chemical reaction is analysed without using the general formalism of non-equilibrium thermodynamics at a level adequate for advanced undergraduates. In a first approach to the problem, the phenomenological kinetic equation of an elementary first-order reaction is used to show that entropy production is always positive. A…
Efficiency increase of complex production and transport systems management
Directory of Open Access Journals (Sweden)
Kornilov S.
2017-01-01
Full Text Available This article deals with the problem of the reduced efficiency of management in complex production - transport systems due to the lack of co-ordination in the operation of industrial enterprises and transport carrying out their maintenance. The existing transport service schedules for auxiliary departments do not take into account possible changes in operating conditions, the probability of malfunctions and the amount of reserves, which leads to an increase in general production costs. To solve this problem, we propose to use the interval regulation of production and transport processes in all departments of the complex production and transport systems. Also, such regulation involves the determination of traffic service priority. This will allow passing on from the regulated control of production and transport processes to the situational one, adapted to specific conditions, and reducing losses from untimely transport servicing, which will lead to a stores reduction and efficiency increase of the enterprise circulating facilities use. Testing the effectiveness of interval regulation was performed on the system and dynamics simulation model of liquid iron transportation in the oxygen converter shop of the metallurgical enterprise. It was established that the use of interval regulation processes in iron production and its transportation will allow decreasing non-productive downtime by 21% and the amount of the liquid iron in anticipation of recasting in the oxygen converter shop – by 33%. Economical effect of reducing the liquid iron downtime during transportation to the oxygen converter shop will be about 30 million rubles per year.
Technical efficiency in milk production in underdeveloped production environment of India*.
Bardhan, Dwaipayan; Sharma, Murari Lal
2013-12-01
The study was undertaken in Kumaon division of Uttarakhand state of India with the objective of estimating technical efficiency in milk production across different herd-size category households and factors influencing it. Total of 60 farm households having representation from different herd-size categories drawn from six randomly selected villages of plain and hilly regions of the division constituted the ultimate sampling units of the study. Stochastic frontier production function analysis was used to estimate the technical efficiency in milk production. Multivariate regression equations were fitted taking technical efficiency index as the regressand to identify the factors significantly influencing technical efficiency in milk production. The study revealed that variation in output across farms in the study area was due to difference in their technical efficiency levels. However, it was interesting to note that smallholder producers were more technically efficient in milk production than their larger counterparts, especially in the plains. Apart from herd size, intensity of market participation had significant and positive impact on technical efficiency in the plains. This provides definite indication that increasing the level of commercialization of dairy farms would have beneficial impact on their production efficiency.
Entropy Generation Analysis of Desalination Technologies
Directory of Open Access Journals (Sweden)
John H. Lienhard V
2011-09-01
Full Text Available Increasing global demand for fresh water is driving the development and implementation of a wide variety of seawater desalination technologies. Entropy generation analysis, and specifically, Second Law efficiency, is an important tool for illustrating the influence of irreversibilities within a system on the required energy input. When defining Second Law efficiency, the useful exergy output of the system must be properly defined. For desalination systems, this is the minimum least work of separation required to extract a unit of water from a feed stream of a given salinity. In order to evaluate the Second Law efficiency, entropy generation mechanisms present in a wide range of desalination processes are analyzed. In particular, entropy generated in the run down to equilibrium of discharge streams must be considered. Physical models are applied to estimate the magnitude of entropy generation by component and individual processes. These formulations are applied to calculate the total entropy generation in several desalination systems including multiple effect distillation, multistage flash, membrane distillation, mechanical vapor compression, reverse osmosis, and humidification-dehumidification. Within each technology, the relative importance of each source of entropy generation is discussed in order to determine which should be the target of entropy generation minimization. As given here, the correct application of Second Law efficiency shows which systems operate closest to the reversible limit and helps to indicate which systems have the greatest potential for improvement.
Profitability and Technical Efficiency of Soybean Production in Northern Nigeria
Directory of Open Access Journals (Sweden)
Ugbabe, OO.
2017-01-01
Full Text Available The International Institute of Tropical Agriculture and collaborating partners have been introducing and disseminating short season soybean varieties among farm households in the Sudan savannas of Northern Nigeria since 2008. Yet, there is no empirical information on the profitability and technical efficiency of soybean production. This study estimated the profitability and efficiency of production of the early maturing soybean. Nine hundred soybean farming households in thirty communities from three Local Government Areas (LGAs in Kano State were sampled for the study. Partial budget technique and stochastic frontier production function were used to analyze the data elicited from the sampled farm households. Results from the study established the profitability of soybean production in all the three LGAs of Kano State. The highest profit of N178,613/ha and returns per naira invested of 2.5 respectively was earned by the soybean producing households of Dawakin-Tofa LGA. Net profit was N157,261in Shanono with a returns of 1.75 per naira invested. In Bunkure, net benefit was N143,342 with returns of 1.66 per Naira invested. The mean technical efficiency was highest for the Dawakin-Tofa LGA soybean growing households (87%, followed by Bunkure LGA (68%, and Shanono LGA (59%. This result implies that given the current level of resources available to the soybean producing households, they can increase their soybean output in the short run by a margin 13%, 32% and 41% in Dawakin-Tofa, Bunkure and Shanono LGAs respectively through efficient utilization of their available resources. Farmer-specific efficiency factors, which comprise age, education, access to credit, extension contact and farming experience, were found to be the significant factors that account for the observed variation in efficiency among the farmers in the 3 LGAs. It was recommended that the soybean farmers through the assistance of extension agents should be encouraged to adhere
ADDED VALUE AS EFFICIENCY CRITERION FOR INDUSTRIAL PRODUCTION PROCESS
Directory of Open Access Journals (Sweden)
L. M. Korotkevich
2016-01-01
Full Text Available Literary analysis has shown that the majority of researchers are using classical efficiency criteria for construction of an optimization model for production process: profit maximization; cost minimization; maximization of commercial product output; minimization of back-log for product demand; minimization of total time consumption due to production change. The paper proposes to use an index of added value as an efficiency criterion because it combines economic and social interests of all main interested subjects of the business activity: national government, property owners, employees, investors. The following types of added value have been considered in the paper: joint-stock, market, monetary, economic, notional (gross, net, real. The paper makes suggestion to use an index of real value added as an efficiency criterion. Such approach permits to bring notional added value in comparable variant because added value can be increased not only due to efficiency improvement of enterprise activity but also due to environmental factors – excess in rate of export price increases over rate of import growth. An analysis of methods for calculation of real value added has been made on a country-by-country basis (extrapolation, simple and double deflation. A method of double deflation has been selected on the basis of the executed analysis and it is counted according to the Laspeyires, Paasche, Fischer indices. A conclusion has been made that the used expressions do not take into account fully economic peculiarities of the Republic of Belarus: they are considered as inappropriate in the case when product cost is differentiated according to marketing outlets; they do not take account of difference in rate of several currencies and such approach is reflected in export price of a released product and import price for raw material, supplies and component parts. Taking this into consideration expressions for calculation of real value added have been specified
Challenges in biobutanol production: How to improve the efficiency?
Energy Technology Data Exchange (ETDEWEB)
Garcia, Veronica; Paekkilae, Johanna; Muurinen, Esa; Keiski, Riitta L. [Mass and Heat Transfer Process Laboratory, Department of Process and Environmental Engineering, POB 4300, FI-90014 University of Oulu, Oulu (Finland); Ojamo, Heikki [Bioprocess Engineering Laboratory, Department of Process and Environmental Engineering, POB 4300, FI-90014 University of Oulu, Oulu (Finland)
2011-02-15
There is an increasing interest in the production of chemicals and fuels from renewable resources due to the continuing price increase of fossil resources, the insecurity of the availability of fossil resources in the future, and additionally environmental concerns and legislations. Biobutanol may be produced by the acetone-butanol-ethanol (ABE) fermentation. This paper reviews the biobutanol production bringing up the problems and challenges to overcome. The aim of the paper is to help in finding opportunities to make the process feasible in the near future. The analysis stresses the idea of improving the efficiency of the fermentation stage by altering the up (pretreatment of the raw material) and downstream (product recovery and purification) processes. The paper also explores the biobutanol production from the biorefinery perspective. Finally the review brings up the important role of research in developing and implementing the production of biobutanol by the ABE fermentation. (author)
Challenges in biobutanol production: How to improve the efficiency?
International Nuclear Information System (INIS)
Garcia, Veronica; Paekkilae, Johanna; Muurinen, Esa; Keiski, Riitta L.; Ojamo, Heikki
2011-01-01
There is an increasing interest in the production of chemicals and fuels from renewable resources due to the continuing price increase of fossil resources, the insecurity of the availability of fossil resources in the future, and additionally environmental concerns and legislations. Biobutanol may be produced by the acetone-butanol-ethanol (ABE) fermentation. This paper reviews the biobutanol production bringing up the problems and challenges to overcome. The aim of the paper is to help in finding opportunities to make the process feasible in the near future. The analysis stresses the idea of improving the efficiency of the fermentation stage by altering the up (pretreatment of the raw material) and downstream (product recovery and purification) processes. The paper also explores the biobutanol production from the biorefinery perspective. Finally the review brings up the important role of research in developing and implementing the production of biobutanol by the ABE fermentation. (author)
Energy security for India: Biofuels, energy efficiency and food productivity
International Nuclear Information System (INIS)
Gunatilake, Herath; Roland-Holst, David; Sugiyarto, Guntur
2014-01-01
The emergence of biofuel as a renewable energy source offers opportunities for significant climate change mitigation and greater energy independence to many countries. At the same time, biofuel represents the possibility of substitution between energy and food. For developing countries like India, which imports over 75% of its crude oil, fossil fuels pose two risks—global warming pollution and long-term risk that oil prices will undermine real living standards. This paper examines India's options for managing energy price risk in three ways: biofuel development, energy efficiency promotion, and food productivity improvements. Our salient results suggest that biodiesel shows promise as a transport fuel substitute that can be produced in ways that fully utilize marginal agricultural resources and hence promote rural livelihoods. First-generation bioethanol, by contrast, appears to have a limited ability to offset the impacts of oil price hikes. Combining the biodiesel expansion policy with energy efficiency improvements and food productivity increases proved to be a more effective strategy to enhance both energy and food security, help mitigate climate change, and cushion the economy against oil price shocks. - Highlights: • We investigate the role of biofuels in India applying a CGE model. • Biodiesel enhances energy security and improve rural livelihoods. • Sugarcane ethanol does not show positive impact on the economy. • Biodiesel and energy efficiency improvements together provide better results. • Food productivity further enhances biodiesel, and energy efficiency impacts
Scaling production and improving efficiency in DEA: an interactive approach
Rödder, Wilhelm; Kleine, Andreas; Dellnitz, Andreas
2017-10-01
DEA models help a DMU to detect its (in-)efficiency and to improve activities, if necessary. Efficiency is only one economic aim for a decision-maker; however, up- or downsizing might be a second one. Improving efficiency is the main topic in DEA; the long-term strategy towards the right production size should attract our attention as well. Not always the management of a DMU primarily focuses on technical efficiency but rather is interested in gaining scale effects. In this paper, a formula for returns to scale (RTS) is developed, and this formula is even applicable for interior points of technology. Particularly, technical and scale inefficient DMUs need sophisticated instruments to improve their situation. Considering RTS as well as efficiency, in this paper, we give an advice for each DMU to find an economically reliable path from its actual situation to better activities and finally to most productive scale size (mpss), perhaps. For realizing this path, we propose an interactive algorithm, thus harmonizing the scientific findings and the interests of the management. Small numerical examples illustrate such paths for selected DMUs; an empirical application in theatre management completes the contribution.
Quantum dynamical entropy revisited
International Nuclear Information System (INIS)
Hudetz, T.
1996-10-01
We define a new quantum dynamical entropy, which is a 'hybrid' of the closely related, physically oriented entropy introduced by Alicki and Fannes in 1994, and of the mathematically well-developed, single-argument entropy introduced by Connes, Narnhofer and Thirring in 1987. We show that this new quantum dynamical entropy has many properties similar to the ones of the Alicki-Fannes entropy, and also inherits some additional properties from the CNT entropy. In particular, the 'hybrid' entropy interpolates between the two different ways in which both the AF and the CNT entropy of the shift automorphism on the quantum spin chain agree with the usual quantum entropy density, resulting in even better agreement. Also, the new quantum dynamical entropy generalizes the classical dynamical entropy of Kolmogorov and Sinai in the same way as does the AF entropy. Finally, we estimate the 'hybrid' entropy both for the Powers-Price shift systems and for the noncommutative Arnold map on the irrational rotation C * -algebra, leaving some interesting open problems. (author)
Resource Use Efficiency Analysis for Potato Production in Nepal
Directory of Open Access Journals (Sweden)
Mahesh Sapkota
2018-05-01
Full Text Available Potato is one of the most important staple foods supporting food security and livelihood to millions of marginalized and poor farmers in Nepal. Generally the smallholders’ farmers, especially those located in remote villages are inadequately informed about technical knowledge, inputs and efficient use of resources causing poor production and low productivity. Thus, the present survey aimed to examine the efficiency of resources used in potato production in Baglung District, one of the remote hilly place located in Central Himalaya. The total of 120 potato growing households was selected using simple random sampling technique from the two potato pocket in 2016. The regression coefficients of each inputs using Cobb-Douglas production function were estimated using Stata software. Our results showed that major inputs such as labor, bullock, Farm Yard Manure (FYM and intercultural operations were overused and need to decrease in terms of cost by 109, 177, 51 and 185%, respectively for its optimum allocation. Similarly, seed was found underused and need to increase its cost by 70% for optimum allocation. We concluded that inadequate training, exposure, knowledge gap and extension service to farmers in study sites were the reasons that farmers were using their resources inefficiently. It is recommended that the farmers involved in potato farming in the surveyed sites should be provided with additional proper technical knowledge for optimizing the use of resources which would help to increase the production and return from potato production.
ECONOMIC EFFICIENCY OF DIFFERENT PROTECTION TREATMENTS IN APPLE PRODUCTION
Directory of Open Access Journals (Sweden)
Vesna Tomaš
2015-06-01
Full Text Available Apple is the most represented fruit species in Croatia. Codling moth, Cydia pomonella L, is one of the most important apple pests whose population is growing from year to year. The aim of this study was to determine the economic effectiveness of four treatments against codling moth (1 - based on baculovirus; 2 - based on the group of synthetic pyrethroid; 3 - based on kaolin, 4 - control treatment, on the three apple varieties. The experiment was performed at the Agricultural Institute Osijek, Croatia, during three years (2012-2014. In order to analyze the results of apple production it was necessary to calculate production efficiency, labor productivity, and profitability of production. The results of the research of economic efficiency according to market prices treatment 1 and treatment 2 had economic coefficient above 1 with tendency of significant growth, while treatment 3 and 4 were uneconomical. The treatment 1showed advantage over the treatment 2 because of its positive effects on human health and biodiversity, as well as satisfactory economic efficiency.
International Nuclear Information System (INIS)
Ye, Xuemin; Li, Chunxi
2013-01-01
As one of the most significant measures to improve energy utilization efficiency and save energy, cogeneration or combined heat and power (CHP) has been widely applied and promoted with positive motivations in many countries. A rational cost allocation model should indicate the performance of cogenerations and balance the benefits between electricity generation and heat production. Based on the second law of thermodynamics, the present paper proposes an entropy change method for cost allocation by choosing exhaust steam entropy as a datum point, and the new model works in conjunction with entropy change and irreversibility during energy conversion processes. The allocation ratios of heat cost with the present and existing methods are compared for different types of cogenerations. Results show that the allocation ratios with the entropy change method are more rational and the cost allocation model can make up some limitations involved in other approaches. The future energy policies and innovational directions for cogenerations and heat consumers should be developed. - Highlights: • A rational model of cogeneration cost allocation is established. • Entropy change method integrates the relation of entropy change and exergy losses. • The unity of measuring energy quality and quantity is materialized. • The benefits between electricity generation and heat production are balanced
Considerations for higher efficiency and productivity in research activities.
Forero, Diego A; Moore, Jason H
2016-01-01
There are several factors that are known to affect research productivity; some of them imply the need for large financial investments and others are related to work styles. There are some articles that provide suggestions for early career scientists (PhD students and postdocs) but few publications are oriented to professors about scientific leadership. As academic mentoring might be useful at all levels of experience, in this note we suggest several key considerations for higher efficiency and productivity in academic and research activities. More research is needed into the main work style features that differentiate highly productive scientists and research groups, as some of them could be innate and others could be transferable. As funding agencies, universities and research centers invest large amounts of money in order to have a better scientific productivity, a deeper understanding of these factors will be of high academic and societal impact.
Directory of Open Access Journals (Sweden)
Urban Kordes
2005-10-01
Full Text Available The paper tries to tackle the question of connection between entropy and the living. Definitions of life as the phenomenon that defies entropy are overviewed and the conclusion is reached that life is in a way dependant on entropy - it couldn't exist without it. Entropy is a sort of medium, a fertile soil, that gives life possibility to blossom. Paper ends with presenting some consequences for the field of artificial intelligence.
Entropy of Baker's Transformation
Institute of Scientific and Technical Information of China (English)
栾长福
2003-01-01
Four theorems about four different kinds of entropies for Baker's transformation are presented. The Kolmogorov entropy of Baker's transformation is sensitive to the initial flips by the time. The topological entropy of Baker's transformation is found to be log k. The conditions for the state of Baker's transformation to be forbidden are also derived. The relations among the Shanonn, Kolmogorov, topological and Boltzmann entropies are discussed in details.
New efficient hydrogen process production from organosilane hydrogen carriers derivatives
Energy Technology Data Exchange (ETDEWEB)
Brunel, Jean Michel [Unite URMITE, UMR 6236 CNRS, Faculte de Medecine et de Pharmacie, Universite de la Mediterranee, 27 boulevard Jean Moulin, 13385 Marseille 05 (France)
2010-04-15
While the source of hydrogen constitutes a significant scientific challenge, addressing issues of hydrogen storage, transport, and delivery is equally important. None of the current hydrogen storage options, liquefied or high pressure H{sub 2} gas, metal hydrides, etc.. satisfy criteria of size, costs, kinetics, and safety for use in transportation. In this context, we have discovered a methodology for the production of hydrogen on demand, in high yield, under kinetic control, from organosilane hydrogen carriers derivatives and methanol as co-reagent under mild conditions catalyzed by a cheap ammonium fluoride salt. Finally, the silicon by-products can be efficiently recycle leading to an environmentally friendly source of energy. (author)
Achieving energy efficiency through product policy: the UK experience
International Nuclear Information System (INIS)
Boardman, Brenda
2004-01-01
The focus of this paper is on energy efficiency of domestic equipment. It is contended that, in the UK and--by extension--elsewhere. Government has to take the lead in defining low-energy standards for products. In the absence of policy, manufacturers do not recognize the need for carbon reductions in the equipment they design and consumers are unaware of the variation in energy performance in the product range. At present, neither market pull nor technology push can be relied upon to deliver energy savings. The imposition of a weak minimum standard on domestic fridges and freezers in 1999 will, over the lifetime of the appliances already sold by December 2002, save 1 Mt C of carbon dioxide at nil cost to government or to the manufacturers, and a net benefit to consumers of pound 855 m: a highly cost-effective policy. The difference between energy efficiency and energy conservation is that it takes time for the cumulative benefits of an energy efficiency improvement to result in the maximum effect on energy demand reduction: the benefits of the 1999 energy efficiency standard will accumulate until at least 2020. This period is equivalent to the cycle of stock replacement for that particular object. The final level of energy conservation depends upon the offsetting effects of growth in ownership levels and the size of new equipment purchases
Material efficiency: providing material services with less material production.
Allwood, Julian M; Ashby, Michael F; Gutowski, Timothy G; Worrell, Ernst
2013-03-13
Material efficiency, as discussed in this Meeting Issue, entails the pursuit of the technical strategies, business models, consumer preferences and policy instruments that would lead to a substantial reduction in the production of high-volume energy-intensive materials required to deliver human well-being. This paper, which introduces a Discussion Meeting Issue on the topic of material efficiency, aims to give an overview of current thinking on the topic, spanning environmental, engineering, economics, sociology and policy issues. The motivations for material efficiency include reducing energy demand, reducing the emissions and other environmental impacts of industry, and increasing national resource security. There are many technical strategies that might bring it about, and these could mainly be implemented today if preferred by customers or producers. However, current economic structures favour the substitution of material for labour, and consumer preferences for material consumption appear to continue even beyond the point at which increased consumption provides any increase in well-being. Therefore, policy will be required to stimulate material efficiency. A theoretically ideal policy measure, such as a carbon price, would internalize the externality of emissions associated with material production, and thus motivate change directly. However, implementation of such a measure has proved elusive, and instead the adjustment of existing government purchasing policies or existing regulations-- for instance to do with building design, planning or vehicle standards--is likely to have a more immediate effect.
Energy sources consumption: end uses, efficiency and productivity
International Nuclear Information System (INIS)
Martin, J.M.
2005-01-01
This document analyzes the impact of the choices made by all actors, from the energy producers to the process and infrastructure designers and the end users, in the evolution of energy consumptions. Some very little improvements made in the energy efficiency of appliances can become equivalent to the production of several oil fields or power plants at the world scale. More efficient energy uses will not replace the additional productions but they must be considered together to be compared. The energy files are first analyzed as a whole in order to show the hidden field of energy choices. In this framework, users, designers and fitters have to face very different choices because they consider efficiency improvements under different aspects: scientifical, technical, economical and social (public information and habits). These differences in efficiency uses have a time and spatial impact on the growth of energy consumption. The economical and social factors influence the collective way to consume energy and are expressed by the energy intensity of the economic activity. The last part of this document analyzes the influence of this notion on the world energy consumption scenarios at the 2050 prospects. (J.S.)
Energy efficiency and econometric analysis of broiler production farms
International Nuclear Information System (INIS)
Heidari, M.D.; Omid, M.; Akram, A.
2011-01-01
The objective of this study was to determine the energy consumption per 1000 bird for the broiler production in Yazd province, Iran. The data were collected from 44 farms by using a face-to-face questionnaire method during January–February 2010. The collected information was analyzed using descriptive statistics, economic analysis and stochastic frontier production function. The production technology of the farmer was assumed to be specified by the Cobb–Douglas (CD) production function. Total input energy was found to be 186,885.87 MJ (1000 bird) −1 while the output energy was 27,461.21 MJ (1000 bird) −1 . The values of specific energy and energy ratio were calculated at 71.95 MJ kg −1 and 0.15, respectively. The sensitivity of energy inputs was estimated using the marginal physical productivity (MPP) method. The MPP value showed the high impact of human labor and machinery energy inputs on output energy. Returns to scale (RTS) values for broiler were found to be 0.96; thus, there prevailed a decreasing RTS for the estimated model. The net return was found positive, as 1386.53 $ (1000 bird) −1 and the benefit to cost ratio from broiler production was calculated to be 1.38. The study revealed that production of meat was profitable in the studied area. -- Highlights: ► We determined the energy use efficiency (EUE) for the broiler production as 0.15, indicating inefficiency use of energy in these farms. ► Total input and output energies were found to be 186,885.87 MJ (1000 bird) −1 and 27,461.21 MJ (1000 bird) −1 , respectively. ► Cobb–Douglas (CD) frontier production function was found useful in developing econometric model for broiler production. ► The results of budgetary analysis indicate production of meat in broiler farms is profitable in the studied area.
Ben-Naim, Arieh
2011-01-01
Changes in entropy can "sometimes" be interpreted in terms of changes in disorder. On the other hand, changes in entropy can "always" be interpreted in terms of changes in Shannon's measure of information. Mixing and demixing processes are used to highlight the pitfalls in the association of entropy with disorder. (Contains 3 figures.)
Productivity, Efficiency, and Competitiveness of Small-Scale Organic Cotton Production in Tanzania
DEFF Research Database (Denmark)
Mgeni, Dotto; Henningsen, Arne
cannot be adjusted in the short run. However, land, labor, and organic fertilizer can neither be traded on a perfect market nor are their quantities completely fixed for cotton production, but these input quantities can be adjusted by adjusting their use for other activities of the household. Hence......Cotton is known as the “white gold” of Africa since it is the only export crop in which the continent’s share in the world market has increased over the past decades. Total cotton production as well as productivity grew particularly in Western and Central Africa. In contrast, cotton production grew...... and output, as well as socio-economic and agronomic factors, but also on the shadow prices of all sparsely traded inputs, i.e. land, labor, and organic fertilizer. Hence, we can not only analyze productivity, technical efficiency, and scale efficiency, but also allocative efficiency, profitability...
Electronic medical records and efficiency and productivity during office visits.
Furukawa, Michael F
2011-04-01
To estimate the relationship between electronic medical record (EMR) use and efficiency of utilization and provider productivity during visits to US office-based physicians. Cross-sectional analysis of the 2006-2007 National Ambulatory Medical Care Survey. The sample included 62,710 patient visits to 2625 physicians. EMR systems included demographics, clinical notes, prescription orders, and laboratory and imaging results. Efficiency was measured as utilization of examinations, laboratory tests, radiology procedures, health education, nonmedication treatments, and medications. Productivity was measured as total services provided per 20-minute period. Survey-weighted regressions estimated association of EMR use with services provided, visit intensity/duration, and productivity. Marginal effects were estimated by averaging across all visits and by major reason for visit. EMR use was associated with higher probability of any examination (7.7%, 95% confidence interval [CI] = 2.4%, 13.1%); any laboratory test (5.7%, 95% CI = 2.6%, 8.8%); any health education (4.9%, 95% CI = 0.2%, 9.6%); and fewer laboratory tests (-7.1%, 95% CI = -14.2%, -0.1%). During pre/post surgery visits, EMR use was associated with 7.3% (95% CI= -12.9%, -1.8%) fewer radiology procedures. EMR use was not associated with utilization of nonmedication treatments and medications, or visit duration. During routine visits for a chronic problem, EMR use was associated with 11.2% (95% CI = 5.7%, 16.8%) more diagnostic/screening services provided per 20-minute period. EMR use had a mixed association with efficiency and productivity during office visits. EMRs may improve provider productivity, especially during visits for a new problem and routine chronic care.
Directory of Open Access Journals (Sweden)
Akhmad Sodiq
2009-09-01
Full Text Available Feed resources are the major constraint in increasing goat production in the village. The main constraints to goat raising are related to feeds (i the high cost of transport of crop residues and grass to the homesteads, (ii the low nutritive value of feeds used, particularly in the dry period. This research was design to evaluate goat productivity and economic efficiency of goat farming under application of feed technology production system in Peranakan Etawah goat farmer group of Gumelar Banyumas Central Java. All farmers were taken as respondents using census methods. On farm research with participative focused group discussion, indepth interview, and farm observation. Descriptive analysis and independent t test methods were used to analyze the data. Results of this study showed that there was a significant improvement goat productivity on production system with the application of feed technology. Body weight at weaning, survival rate till weaning, and doe productivity were increased 7%, 2% and 5%, respectively. There was no evidence of significant different of farmers income and economic efficiency before and after the applied feed technology (P>0.05. The calculation was based on cash flow. Before application, farmers income per year and economic efficiency were Rp14.404.520,00 and 1.21, then insignificantly improve into Rp16.487.100,00 and 1.27, respectively. (Animal Production 11(3: 202-208 (2009 Key Words: Livestock production system, Peranakan Etawah goat, feed technology aplication, productivity and economic efficiency
Efficient recombinant production of prodigiosin in Pseudomonas putida
Directory of Open Access Journals (Sweden)
Andreas eDomröse
2015-09-01
Full Text Available Serratia marcescens and several other bacteria produce the red-colored pigment prodigiosin which possesses bioactivities as an antimicrobial, anticancer and immunosuppressive agent. Therefore, there is a great interest to produce this natural compound. Efforts aiming at its biotechnological production have so far largely focused on the original producer and opportunistic human pathogen S. marcescens. Here, we demonstrate efficient prodigiosin production in the heterologous host Pseudomonas putida. Random chromosomal integration of the 21 kb prodigiosin biosynthesis gene cluster of S. marcescens in P. putida KT2440 was employed to construct constitutive prodigiosin production strains. Standard cultivation parameters were optimized such that titers of 94 mg/L culture were obtained upon growth of P. putida at 20 °C using rich medium under high aeration conditions. Subsequently, a novel, fast and effective protocol for prodigiosin extraction and purification was established enabling the straightforward isolation of prodigiosin from P. putida growth medium. In summary, we describe here a highly efficient method for the heterologous biosynthetic production of prodigiosin which may serve as a basis to produce large amounts of this bioactive natural compound and may provide a platform for further in-depth studies of prodiginine biosynthesis.
Production and efficiency of organic compost generated by millipede activity
Directory of Open Access Journals (Sweden)
Luiz Fernando de Sousa Antunes
2016-05-01
Full Text Available ABSTRACT: The putrefactive activity of organisms such as diplopods in the edaphic macrof auna can be leveraged to promote the transformation of agricultural and urban waste into a low-cost substrate for the production of vegetable seedlings. This research aimed to evaluate: (1 the quantity of Gervais millipedes ( Trigoniulus corallinus needed to produce an acceptable quantity of organic compost; (2 the main physical and chemical characteristics of different compost types; and (3 compost efficiency in the production of lettuce seedlings. The first experiment lasted 90 days and was conducted using 6.5L of Gliricidia, 6.5L of Flemingia, 13.5L of grass cuttings, 4.5L of cardboard, 4.5L of coconut husk, and 4.5L of corncob. Treatments consisting of 0, 0.10, 0.30, 0.50, and 0.90L of millipedes were applied. This experiment compared millicompost and vermicompost, using four repetitions. After 23 days, the heights of grown lettuce plants and the weights of the fresh and dry mass of above ground lettuce and of the roots were assessed. A millipede volume of 0.1L proved to be sufficient for the production of an acceptable volume of organic compost. However, the addition of greater volumes leads to increased calcium, magnesium, and phosphorous content. Millicompost has similar physicochemical characteristics those of vermicompost, and both are equally efficient as a substrate for the production of lettuce seedlings.
Gravitational entropies in LTB dust models
International Nuclear Information System (INIS)
Sussman, Roberto A; Larena, Julien
2014-01-01
We consider generic Lemaître–Tolman–Bondi (LTB) dust models to probe the gravitational entropy proposals of Clifton, Ellis and Tavakol (CET) and of Hosoya and Buchert (HB). We also consider a variant of the HB proposal based on a suitable quasi-local scalar weighted average. We show that the conditions for entropy growth for all proposals are directly related to a negative correlation of similar fluctuations of the energy density and Hubble scalar. While this correlation is evaluated locally for the CET proposal, it must be evaluated in a non-local domain dependent manner for the two HB proposals. By looking at the fulfilment of these conditions at the relevant asymptotic limits we are able to provide a well grounded qualitative description of the full time evolution and radial asymptotic scaling of the three entropies in generic models. The following rigorous analytic results are obtained for the three proposals: (i) entropy grows when the density growing mode is dominant, (ii) all ever-expanding hyperbolic models reach a stable terminal equilibrium characterized by an inhomogeneous entropy maximum in their late time evolution; (iii) regions with decaying modes and collapsing elliptic models exhibit unstable equilibria associated with an entropy minimum (iv) near singularities the CET entropy diverges while the HB entropies converge; (v) the CET entropy converges for all models in the radial asymptotic range, whereas the HB entropies only converge for models asymptotic to a Friedmann–Lemaître–Robertson–Walker background. The fact that different independent proposals yield fairly similar conditions for entropy production, time evolution and radial scaling in generic LTB models seems to suggest that their common notion of a ‘gravitational entropy’ may be a theoretically robust concept applicable to more general spacetimes. (paper)
High efficiency power production from biomass and waste
Energy Technology Data Exchange (ETDEWEB)
Rabou, L.P.L.M.; Van Leijenhorst, R.J.C.; Hazewinkel, J.H.O. [ECN Biomass, Coal and Environment, Petten (Netherlands)
2008-11-15
Two-stage gasification allows power production from biomass and waste with high efficiency. The process involves pyrolysis at about 550C followed by heating of the pyrolysis gas to about 1300C in order to crack hydrocarbons and obtain syngas, a mixture of H2, CO, H2O and CO2. The second stage produces soot as unwanted by-product. Experimental results are reported on the suppression of soot formation in the second stage for two different fuels: beech wood pellets and Rofire pellets, made from rejects of paper recycling. Syngas obtained from these two fuels and from an industrial waste fuel has been cleaned and fed to a commercial SOFC stack for 250 hours in total. The SOFC stack showed comparable performance on real and synthetic syngas and no signs of accelerated degradation in performance over these tests. The experimental results have been used for the design and analysis of a future 25 MWth demonstration plant. As an alternative, a 2.6 MWth system was considered which uses the Green MoDem approach to convert waste fuel into bio-oil and syngas. The 25 MWth system can reach high efficiency only if char produced in the pyrolysis step is converted into additional syngas by steam gasification, and if SOFC off-gas and system waste heat are used in a steam bottoming cycle for additional power production. A net electrical efficiency of 38% is predicted. In addition, heat can be delivered with 37% efficiency. The 2.6 MWth system with only a dual fuel engine to burn bio-oil and syngas promises nearly 40% electrical efficiency plus 41% efficiency for heat production. If syngas is fed to an SOFC system and off-gas and bio-oil to a dual fuel engine, the electrical efficiency can rise to 45%. However, the efficiency for heat production drops to 15%, as waste heat from the SOFC system cannot be used effectively. The economic analysis makes clear that at -20 euro/tonne fuel, 70 euro/MWh for electricity and 7 euro/GJ for heat the 25 MWth system is not economically viable at the
Volkenstein, Mikhail V
2009-01-01
The book "Entropy and Information" deals with the thermodynamical concept of entropy and its relationship to information theory. It is successful in explaining the universality of the term "Entropy" not only as a physical phenomenon, but reveals its existence also in other domains. E.g., Volkenstein discusses the "meaning" of entropy in a biological context and shows how entropy is related to artistic activities. Written by the renowned Russian bio-physicist Mikhail V. Volkenstein, this book on "Entropy and Information" surely serves as a timely introduction to understand entropy from a thermodynamic perspective and is definitely an inspiring and thought-provoking book that should be read by every physicist, information-theorist, biologist, and even artist.
Temperature dependent fission product removal efficiency due to pool scrubbing
Energy Technology Data Exchange (ETDEWEB)
Uchida, Shunsuke, E-mail: suchida@iae.or.jp [Institute of Applied Energy, 1-14-2, Nishi-Shimbashi, Minato-ku, Tokyo 105-0003 (Japan); Itoh, Ayumi; Naitoh, Masanori; Okada, Hidetoshi; Suzuki, Hiroyuki [Institute of Applied Energy, 1-14-2, Nishi-Shimbashi, Minato-ku, Tokyo 105-0003 (Japan); Hanamoto, Yukio [KAKEN, Inc., 1044, Hori-machi, Mito 310-0903 (Japan); Osakabe, Masahiro [Tokyo University of Marine Science & Technology, Koutou-ku, Tokyo 135-8533 (Japan); Fujikawa, Masahiro [Japan Broadcasting Corporation, 2-2-1, Jinnan, Shibuya-ku, Tokyo 150-8001 (Japan)
2016-03-15
Highlights: • Pool temperature effects on the FP removal were not clearly concluded in the previous publications. • It was confirmed that the removal efficiency decreased with temperature around the boiling point. • A modified empirical formula for FP removal was proposed as a function of sub-cooling temperature. • DF could be predicted with an accuracy within a factor of 2 with the proposed formula. - Abstract: The wet-well of boiling water reactors plays important roles not only to suppress the pressure in the primary containment vessel due to steam scrubbing effects during severe accidents but also to mitigate release of radioactive fission products (FP), aerosols and particulates, into the environment. The effects of steam scrubbing in the wet-well on FP removal have been well studied and reported by changing major parameters determining the removal efficiencies, e.g., aerosol diameters, submergence (depth of scrubbing nozzles) and steam/non-condensable gas volume fraction. Unfortunately, the effects of pool temperature on the FP removal were not clearly concluded in the previous publications, though it would be easily expected that boiling in the pool resulted in reduced aerosol removal efficiency. In order to determine the temperature effects on FP removal efficiency, amounts of cesium in aerosols released from scrubbing pool were measured by changing pool temperature in mini and medium scale scrubbing experiments, and then, it was confirmed that the removal efficiency clearly decreased with temperature around the boiling point. Then, a modified empirical formula to express the FP removal around the boiling point temperature was proposed as a function of sub-cooling temperature by applying the effective steam volume fraction, which was designated as the volume ratio of condensed steam in the pool versus the sum of input steam and non-condensable gas. By comparing the measured removal efficiency with the calculated, it was validated that the
Temperature dependent fission product removal efficiency due to pool scrubbing
International Nuclear Information System (INIS)
Uchida, Shunsuke; Itoh, Ayumi; Naitoh, Masanori; Okada, Hidetoshi; Suzuki, Hiroyuki; Hanamoto, Yukio; Osakabe, Masahiro; Fujikawa, Masahiro
2016-01-01
Highlights: • Pool temperature effects on the FP removal were not clearly concluded in the previous publications. • It was confirmed that the removal efficiency decreased with temperature around the boiling point. • A modified empirical formula for FP removal was proposed as a function of sub-cooling temperature. • DF could be predicted with an accuracy within a factor of 2 with the proposed formula. - Abstract: The wet-well of boiling water reactors plays important roles not only to suppress the pressure in the primary containment vessel due to steam scrubbing effects during severe accidents but also to mitigate release of radioactive fission products (FP), aerosols and particulates, into the environment. The effects of steam scrubbing in the wet-well on FP removal have been well studied and reported by changing major parameters determining the removal efficiencies, e.g., aerosol diameters, submergence (depth of scrubbing nozzles) and steam/non-condensable gas volume fraction. Unfortunately, the effects of pool temperature on the FP removal were not clearly concluded in the previous publications, though it would be easily expected that boiling in the pool resulted in reduced aerosol removal efficiency. In order to determine the temperature effects on FP removal efficiency, amounts of cesium in aerosols released from scrubbing pool were measured by changing pool temperature in mini and medium scale scrubbing experiments, and then, it was confirmed that the removal efficiency clearly decreased with temperature around the boiling point. Then, a modified empirical formula to express the FP removal around the boiling point temperature was proposed as a function of sub-cooling temperature by applying the effective steam volume fraction, which was designated as the volume ratio of condensed steam in the pool versus the sum of input steam and non-condensable gas. By comparing the measured removal efficiency with the calculated, it was validated that the
Directory of Open Access Journals (Sweden)
Anita Romsdal
2014-07-01
Full Text Available This paper addresses the complex production planning and control (PPC challenges in food supply chains. The study illustrates how food producers' traditional make‐to‐stock (MTS approach is not well suited to meet the trends of increasing product variety, higher demand uncertainty, increasing sales of fresh food products and more demanding customers. The paper proposes a framework for differentiated PPC that combines MTS with make‐to‐order (MTO.The framework matches products with the most appropriate PPC approaches and buffering techniques depending on market and product characteristics. The core idea is to achieve more volume flexibility in the production system by exploiting favourable product and market characteristics (high demand predictability, long customer order leadtime allowances and low product perishability. A case study is used to demonstrate how the framework can enable food producers to achieve efficiency in production, inventory and PPC processes – and simultaneously be responsive to market requirements.
Option price calibration from Renyi entropy
International Nuclear Information System (INIS)
Brody, Dorje C.; Buckley, Ian R.C.; Constantinou, Irene C.
2007-01-01
The calibration of the risk-neutral density function for the future asset price, based on the maximisation of the entropy measure of Renyi, is proposed. Whilst the conventional approach based on the use of logarithmic entropy measure fails to produce the observed power-law distribution when calibrated against option prices, the approach outlined here is shown to produce the desired form of the distribution. Procedures for the maximisation of the Renyi entropy under constraints are outlined in detail, and a number of interesting properties of the resulting power-law distributions are also derived. The result is applied to efficiently evaluate prices of path-independent derivatives
Emission and Absorption Entropy Generation in Semiconductors
DEFF Research Database (Denmark)
Reck, Kasper; Varpula, Aapo; Prunnila, Mika
2013-01-01
While emission and absorption entropy generation is well known in black bodies, it has not previously been studied in semiconductors, even though semiconductors are widely used for solar light absorption in modern solar cells [1]. We present an analysis of the entropy generation in semiconductor...... materials due to emission and absorption of electromagnetic radiation. It is shown that the emission and absorption entropy generation reduces the fundamental limit on the efficiency of any semiconductor solar cell even further than the Landsberg limit. The results are derived from purely thermodynamical...
Entropy generation in a diesel engine turbocharging system
International Nuclear Information System (INIS)
Nakonieczny, K.
2002-01-01
The paper describes a model of entropy production in a diesel engine turbocharging system, discussing the processes occurring in the compressor, turbine, piping system, charge-air cooler and valves with the exclusion of combustion. The charging efficiency of the system is studied in two distinct engine operating states, conforming to maximum torque and nominal power conditions. Unlike in the standard approach, where the irreversibilities are derived from the balance equation for exergy and thus are addressed inexactly, the criterion function based on the notion of entropy generation, introduced in this paper, improves second law analysis of turbocharged engines by accounting for a direct description of the system internal irreversibilities. This function is used for the examination of an impact of the system design parameters on its efficiency. Computations based on the unsteady one-dimensional flow model show that, under the variations of the inlet pipe length, the timings of inlet valve opening and exhaust valve closure, and the valve overlap period, a favourable correlation can be found between the decrease of entropy production and the increase in amount of air charged into the engine cylinders. The other variables under study, including the turbine equivalent area, temperature decrease in intercooler and wastegate effective area ratio, show an opposite correlation, and thus, can be viewed as constraints in the system optimisation
Directory of Open Access Journals (Sweden)
Budi Santosa
2016-01-01
Full Text Available This paper presents a model and an algorithm for an inventory ship routing problem (ISRP. It consists of two main parts: a model development of the ship routing problem in a multi-product inventory with a heterogeneous fleet and an algorithm development to solve the problem. The problem is referred to as ISRP. ISRP considers several parameters including the deadweight tonnage (DWT, product compatibility, port setup, and compartment washing costs. Considering these parameters, the objective function is to minimize the total cost, which consists of traveling, port setup, ship charter, and compartment washing costs. From the resulting model, there are two major steps used to solve the problem. The first is to select the ships in order to satisfy the constraint that restricts the mooring rule. The second is to find the best route, product allocation, and shipped quantity. ISRP is an Non Polynomial-hard problem. Finding the solution of such problem needs a high computation time. A new hybrid metaheuristics, namely the cross entropy-genetic algorithm (CEGA, was proposed to solve ISRP. The results were then compared with those resulted from a hybrid Tabu Search to measure the hybrid CEGA performance. The results showed that CEGA provided better solutions than those produced by the hybrid Tabu Search.
Efficient production of automotive biofuels; Effektiv produktion av biodrivmedel
Energy Technology Data Exchange (ETDEWEB)
Gode, Jenny; Hagberg, Linus; Rydberg, Tomas; Raadberg, Henrik; Saernholm, Erik
2008-07-01
, production of fatty acid methyl ester (FAME), pellets production and in some cases treatment with hydrogen gas, catalytic depolymerisation and anaerobic digestion can increase the use of steam and heat from district heating. This new 'offset' for heat can increase operational hours for the CHP. Conversely, biomass gasification produces a greater proportion of the necessary process energy internally and the waste heat produced in the process leads to a lower load for heat production in the CHP. These conclusions are illustrated in the form of a diagram of heat output distribution, both for the hypothetical polygeneration plant of ethanol production and for the hypothetical biomass gasification polygeneration plant with production of synthetic natural gas. The calculations are based on a district heating network where the heat is produced from a biofuel driven CHP (89 MW{sub e}, 173 MW{sub heat} and 230 MW{sub fuel}) and a biofuel driven HP. Since the prerequisites for each specific polygeneration plant are different, the effect of integrations in reality would differ from the results of these calculations--but the results give an overview of the consequences of the choice of energy polygeneration plant. Several interesting combinations in the form of biofuel polygeneration plants are already in operation or in the planning stage. Several conceivable alternatives are: - Ethanol production, anaerobic digestion/feed production, heat and power. - Ethanol production, pellets production, greenhouse, heat and power. - Gasification including fuel production, district heating network and pellets production. - Oilseed rape production, RME production, heat and power. - NExBTL production, refinery, district heating network/heat and power. In most cases the overall efficiency of biofuel production is lower than if biomass is used directly in heat and power production as shown in the system analysis. This is, however, in conflict with the increasing demand for biofuels. A biomass
Biomass production efficiency controlled by management in temperate and boreal ecosystems
Campioli, M.; Vicca, S.; Luyssaert, S.; Bilcke, J.; Ceschia, E.; Chapin, F.S. III; Ciais, P.; Fernández-Martínez, M.; Malhi, Y.; Obersteiner, M.; Olefeldt, D.; Papale, D.; Piao, S.L.; Peñuelas, J.; Sullivan, P. F.; Wang, X.; Zenone, T.; Janssens, I.A.
2015-01-01
Plants acquire carbon through photosynthesis to sustain biomass production, autotrophic respiration and production of non-structural compounds for multiple purposes. The fraction of photosynthetic production used for biomass production, the biomass production efficiency, is a key determinant of the
Entropy estimates for simple random fields
DEFF Research Database (Denmark)
Forchhammer, Søren; Justesen, Jørn
1995-01-01
We consider the problem of determining the maximum entropy of a discrete random field on a lattice subject to certain local constraints on symbol configurations. The results are expected to be of interest in the analysis of digitized images and two dimensional codes. We shall present some examples...... of binary and ternary fields with simple constraints. Exact results on the entropies are known only in a few cases, but we shall present close bounds and estimates that are computationally efficient...
Improved energy efficiency in juice production through waste heat recycling
International Nuclear Information System (INIS)
Anderson, J.-O.; Elfgren, E.; Westerlund, L.
2014-01-01
Highlights: • A heating system at a juice production was investigated and improved. • Different impacts of drying cycle improvements at the energy usage were explored. • The total heat use for drying could thereby be decreased with 52%. • The results point out a significant decrease of heat consumption with low investment costs. - Abstract: Berry juice concentrate is produced by pressing berries and heating up the juice. The by-products are berry skins and seeds in a press cake. Traditionally, these by-products have been composted, but due to their valuable nutrients, it could be profitable to sell them instead. The skins and seeds need to be separated and dried to a moisture content of less than 10 %wt (on dry basis) in order to avoid fermentation. A berry juice plant in the north of Sweden has been studied in order to increase the energy and resource efficiency, with special focus on the drying system. This was done by means of process integration with mass and energy balance, theory from thermodynamics and psychrometry along with measurements of the juice plant. Our study indicates that the drying system could be operated at full capacity without any external heat supply using waste heat supplied from the juice plant. This would be achieved by increasing the efficiency of the dryer by recirculation of the drying air and by heat supply from the flue gases of the industrial boiler. The recirculation would decrease the need of heat in the dryer with about 52%. The total heat use for the plant could thereby be decreased from 1262 kW to 1145 kW. The improvements could be done without compromising the production quality
Crop productivities and radiation use efficiencies for bioregenerative life support
Wheeler, R. M.; Mackowiak, C. L.; Stutte, G. W.; Yorio, N. C.; Ruffe, L. M.; Sager, J. C.; Prince, R. P.; Knott, W. M.
NASA’s Biomass Production Chamber (BPC) at Kennedy Space Center was decommissioned in 1998, but several crop tests were conducted that have not been reported in the open literature. These include several monoculture studies with wheat, soybean, potato, lettuce, and tomato. For all of these studies, either 10 or 20 m2 of plants were grown in an atmospherically closed chamber (113 m3 vol.) using a hydroponic nutrient film technique along with elevated CO2 (1000 or 1200 μmol mol-1). Canopy light (PAR) levels ranged from 17 to 85 mol m-2 d-1 depending on the species and photoperiod. Total biomass (DM) productivities reached 39.6 g m-2 d-1 for wheat, 27.2 g m-2 d-1 for potato, 19.6 g m-2 d-1 for tomato, 15.7 g m-2 d-1 for soybean, and 7.7 g m-2 d-1 for lettuce. Edible biomass (DM) productivities reached 18.4 g m-2 d-1 for potato, 11.3 g m-2 d-1 for wheat, 9.8 g m-2 d-1 for tomato, 7.1 g m-2 d-1 for lettuce, and 6.0 g m-2 d-1 for soybean. The corresponding radiation (light) use efficiencies for total biomass were 0.64 g mol-1 PAR for potato, 0.59 g DM mol-1 for wheat, 0.51 g mol-1 for tomato, 0.46 g mol-1 for lettuce, and 0.43 g mol-1 for soybean. Radiation use efficiencies for edible biomass were 0.44 g mol-1 for potato, 0.42 g mol-1 for lettuce, 0.25 g mol-1 for tomato, 0.17 g DM mol-1 for wheat, and 0.16 g mol-1 for soybean. By initially growing seedlings at a dense spacing and then transplanting them to the final production area could have saved about 12 d in each production cycle, and hence improved edible biomass productivities and radiation use efficiencies by 66% for lettuce (to 11.8 g m-2 d-1 and 0.70 g mol-1), 16% for tomato (to 11.4 g m-2 d-1and 0.29 g mol-1), 13% for soybean (to 6.9 g m-2 d-1 and 0.19 g mol-1), and 13% for potato (to 20.8 g m-2 d-1 and 0.50 g mol-1). Since wheat was grown at higher densities, transplanting seedlings would not have improved yields. Tests with wheat resulted in a relatively low harvest index of 29%, which may have been
DEPENDENCE OF ENERGY EFFICIENCY AND COST OF PRODUCTION
Directory of Open Access Journals (Sweden)
D. Sklyarov
2016-01-01
Full Text Available Economic systems exist on condition of receipt and spending of energy. Energy consumption is a necessary condition for the existence and functioning of the economic systems of any scale: macroeconomics, microeconomics, regional economy or the world economy.The economic system operates on the scale at which it is able to produce energy and get access to energy. Moreover, receipt and consumption of energy in the operation of the economic system is mainly determined by, the level of energy production from energy sources, since this level is determined by the level of energy consumption by industries and enterprises of the economy.Currently, the economic system does not produce energy in reserve. Thus, the question of energy effi ciency and energy saving was always acute.The article describes the energy efficiency and energy saving effect on the cost of production. Were used two methods: “costs and release” matrix and “price - value added” matrix. The result is the equation of dependence of energy efficiency and costs.
Consumption of energy and release of entropy into the biosphere
International Nuclear Information System (INIS)
Deutscher, G.
2014-01-01
The short-term threat on humanity is not the shortage of energy but rather the contamination of the environment. The concept of entropy is useful to assess the impact of humane activities on the environment. During most of earth history the increase of entropy was more than compensated by the energy brought by the sun. Today the intensive use of fossil fuels has reversed the trend: the biosphere entropy increases as CO 2 piles up in the atmosphere. The release of entropy is linked to the amount of energy we consume and to the efficiency of the process we use to produce it. Nuclear power plants release entropy as low-temperature heat but this amount of entropy is far less than the entropy released by fossil-fuel power plants under the form of CO 2 . (A.C.)
Watson, Andrew B.; Stone, Leland (Technical Monitor)
1997-01-01
) an Arts and Letters emphasis, and c) a Computer Science emphasis Each pathway includes course work in remote sensing, geographical information systems (GIS), computer science, Earth science, software and technology utilization, and communication. Distribution of products from this project to other two-year colleges will be accomplished using the WWW.
Veysset, P; Lherm, M; Roulenc, M; Troquier, C; Bébin, D
2015-12-01
Over the past 23 years (1990 to 2012), French beef cattle farms have expanded in size and increased labour productivity by over 60%, chiefly, though not exclusively, through capital intensification (labour-capital substitution) and simplifying herd feeding practices (more concentrates used). The technical efficiency of beef sector production systems, as measured by the ratio of the volume value (in constant euros) of farm output excluding aids to volume of intermediate consumption, has fallen by nearly 20% while income per worker has held stable thanks to subsidies and the labour productivity gains made. This aggregate technical efficiency of beef cattle systems is positively correlated to feed self-sufficiency, which is in turn negatively correlated to farm and herd size. While volume of farm output per hectare of agricultural area has not changed, forage feed self-sufficiency decreased by 6 percentage points. The continual increase in farm size and labour productivity has come at a cost of lower production-system efficiency - a loss of technical efficiency that 20 years of genetic, technical, technological and knowledge-driven progress has barely managed to offset.
Maximum Quantum Entropy Method
Sim, Jae-Hoon; Han, Myung Joon
2018-01-01
Maximum entropy method for analytic continuation is extended by introducing quantum relative entropy. This new method is formulated in terms of matrix-valued functions and therefore invariant under arbitrary unitary transformation of input matrix. As a result, the continuation of off-diagonal elements becomes straightforward. Without introducing any further ambiguity, the Bayesian probabilistic interpretation is maintained just as in the conventional maximum entropy method. The applications o...
Transplanckian entanglement entropy
International Nuclear Information System (INIS)
Chang, Darwin; Chu, C.-S.; Lin Fengli
2004-01-01
The entanglement entropy of the event horizon is known to be plagued by the UV divergence due to the infinitely blue-shifted near horizon modes. In this Letter we calculate the entanglement entropy using the transplanckian dispersion relation, which has been proposed to model the quantum gravity effects. We show that, very generally, the entropy is rendered UV finite due to the suppression of high energy modes effected by the transplanckian dispersion relation
2015-09-29
antiferroelectrics. Phys. Rev. Lett. 110, 017603 (2013). 22. Cantor , B., Chang, I., Knight, P. & Vincent, A. Microstructural development in equiatomic...Science 345, 1153–1158 (2014). 24. Gali, A. & George , E. Tensile properties of high- and medium-entropy alloys. Intermetallics 39, 74–78 (2013). 25...148–153 (2014). 26. Otto, F., Yang, Y., Bei, H. & George , E. Relative effects of enthalpy and entropy on the phase stability of equiatomic high-entropy
Entropy viscosity method for nonlinear conservation laws
Guermond, Jean-Luc
2011-05-01
A new class of high-order numerical methods for approximating nonlinear conservation laws is described (entropy viscosity method). The novelty is that a nonlinear viscosity based on the local size of an entropy production is added to the numerical discretization at hand. This new approach does not use any flux or slope limiters, applies to equations or systems supplemented with one or more entropy inequalities and does not depend on the mesh type and polynomial approximation. Various benchmark problems are solved with finite elements, spectral elements and Fourier series to illustrate the capability of the proposed method. © 2010 Elsevier Inc.
Entropy viscosity method for nonlinear conservation laws
Guermond, Jean-Luc; Pasquetti, Richard; Popov, Bojan
2011-01-01
A new class of high-order numerical methods for approximating nonlinear conservation laws is described (entropy viscosity method). The novelty is that a nonlinear viscosity based on the local size of an entropy production is added to the numerical discretization at hand. This new approach does not use any flux or slope limiters, applies to equations or systems supplemented with one or more entropy inequalities and does not depend on the mesh type and polynomial approximation. Various benchmark problems are solved with finite elements, spectral elements and Fourier series to illustrate the capability of the proposed method. © 2010 Elsevier Inc.
International Nuclear Information System (INIS)
Kurnia, Jundika C.; Sasmito, Agus P.; Shamim, Tariq; Mujumdar, Arun S.
2016-01-01
Highlights: • Heat transfers of helical coiled tube with several cross section profiles are evaluated. • Helical tubes offer higher heat transfer and lower entropy generation. • Square cross-section generates the highest entropy, followed by ellipse and circular. • Study could serve as a guideline in designing an efficient helical tube heat exchanger. - Abstract: This study evaluates heat transfer performance and entropy generation of laminar flow in coiled tubes with various cross-sections geometries i.e. circular, ellipse and square, relatives to the straight tubes of similar cross-sections. A computational fluid dynamics model is developed and validated against empirical correlations. Good agreement is obtained within range of Reynolds and Dean numbers considered. Effect of geometry, wall temperature, Reynolds number and heating/cooling mode were examined. To evaluate the heat transfer performance of the coiled tube configurations, a parameter referred as Figure of Merit (FoM) is defined as the ratio heat transfer rate to the required pumping power. In addition, exergy analysis is carried out to examine the inefficiency of the coiled tube configurations. The results indicate that coiled tubes provide higher heat transfer rate. In addition, it was found to be more efficient as reflected by lower entropy generation as compared to straight tubes. Among the studied cross-section, square cross-section generates the highest entropy, followed by ellipse and circular counterpart. Entropy production from heat transfer contribution is two order-of-magnitude higher than that of entropy contribution from viscous dissipation. Cooling case produces slightly higher entropy than heating counterpart. Finally, this study can provide practical guideline to design more efficient coiled heat exchanger.
ENTROPY FUNCTIONAL FOR CONTINUOUS SYSTEMS OF FINITE ENTROPY
Institute of Scientific and Technical Information of China (English)
M. Rahimi A. Riazi
2012-01-01
In this article,we introduce the concept of entropy functional for continuous systems on compact metric spaces,and prove some of its properties.We also extract the Kolmogorov entropy from the entropy functional.
Cooperative procurement: market transformation for energy efficient products
Energy Technology Data Exchange (ETDEWEB)
Ostertag, K.; Dreher, C.
1999-07-01
Cooperative procurement is a variation of public purchasing which may be used as an instrument to transform the market and stimulate innovation enhancing environmental performance. The core of the procedure is the following: Coordinated by a central agency a group of buyers - public administrations, but also private companies, associations, etc. - gets together and jointly formulates a catalogue of performance requirements for a specific product truly suiting their preferences. This catalogue may contain (combinations of) requirements not yet available on the market and includes energy efficiency and/or environmental performance among other preferences important to the users. On the basis of the product requirements the buyer group launches a call for tenders, evaluates the bids received from the manufacturers and commits to buying the winning product. Thus, a market is provided for the most successful innovators in a given area of technology. The paper discusses the effectiveness of cooperative procurement as a policy instrument in the context of innovation theory and learning curves and it presents some empirical results on the feasibility of the transfer of this policy instruments to a wider range of European countries and/or to the European level. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Hampf, Benjamin
2011-08-15
In this paper we present a new approach to evaluate the environmental efficiency of decision making units. We propose a model that describes a two-stage process consisting of a production and an end-of-pipe abatement stage with the environmental efficiency being determined by the efficiency of both stages. Taking the dependencies between the two stages into account, we show how nonparametric methods can be used to measure environmental efficiency and to decompose it into production and abatement efficiency. For an empirical illustration we apply our model to an analysis of U.S. power plants.
Energy Technology Data Exchange (ETDEWEB)
NONE
2010-10-15
This report discusses a number of examples of applications of energy efficient product development. These examples featured on separate web pages of the website www.senternovem.nl/mja from 2006 to 2010. The section on 'explanation of energy benefits' is based on a rough calculation made by SenterNovem. The examples illustrate in which stage(s) of the chain the energy benefit is realized. [Dutch] Dit rapport bevat een aantal voorbeelden van de toepassing van energiezuinige productontwikkeling. Deze voorbeelden hebben van 2006 tot 2010 als afzonderlijke pagina's gestaan op de website www.senternovem.nl/mja. De paragraaf 'Toelichting energiewinst' bij de voorbeelden is gebaseerd op een globale berekening van SenterNovem. De voorbeelden geven aan in welke fase(s) in de keten de energiewinst wordt behaald.
Naturally Efficient Emitters: Luminescent Organometallic Complexes Derived from Natural Products
Zhang, Wen-Hua; Young, David J.
2013-08-01
Naturally occurring molecules offer intricate structures and functionality that are the basis of modern medicinal chemistry, but are under-represented in materials science. Herein, we review recent literature describing the use of abundant and relatively inexpensive, natural products for the synthesis of ligands for luminescent organometallic complexes used for organic light emitting diodes (OLEDs) and related technologies. These ligands are prepared from the renewable starting materials caffeine, camphor, pinene and cinchonine and, with the exception of caffeine, impart performance improvements to the emissive metal complexes and resulting OLED devices, with emission wavelengths that span the visible spectrum from blue to red. The advantages of these biologically-derived molecules include improved solution processibility and phase homogeneity, brighter luminescence, higher quantum efficiencies and lower turn-on voltages. While nature has evolved these carbon-skeletons for specific purposes, they also offer some intriguing benefits in materials science and technology.
Towards an Entropy Stable Spectral Element Framework for Computational Fluid Dynamics
Carpenter, Mark H.
2016-01-04
Nonlinearly stable finite element methods of arbitrary type and order, are currently unavailable for discretizations of the compressible Navier-Stokes equations. Summation-by-parts (SBP) entropy stability analysis provides a means of constructing nonlinearly stable discrete operators of arbitrary order, but is currently limited to simple element types. Herein, recent progress is reported, on developing entropy-stable (SS) discontinuous spectral collocation formulations for hexahedral elements. Two complementary efforts are discussed. The first effort generalizes previous SS spectral collocation work to extend the applicable set of points from tensor product, Legendre-Gauss-Lobatto (LGL) to tensor product Legendre-Gauss (LG) points. The LG and LGL point formulations are compared on a series of test problems. Both the LGL and LG operators are of comparable efficiency and robustness, as is demonstrated using test problems for which conventional FEM techniques suffer instability. The second effort extends previous work on entropy stability to include p-refinement at nonconforming interfaces. A generalization of existing entropy stability theory is required to accommodate the nuances of fully multidimensional SBP operators. The entropy stability of the compressible Euler equations on nonconforming interfaces is demonstrated using the newly developed LG operators and multidimensional interface interpolation operators. Preliminary studies suggest design order accuracy at nonconforming interfaces.
Analysis of product efficiency of hybrid vehicles and promotion policies
International Nuclear Information System (INIS)
Choi, Hyundo; Oh, Inha
2010-01-01
The key aim of this study is to evaluate the product efficiency of current hybrid vehicles and suggest effective policies to promote hybrid vehicles in the Korean automobile market and development trends of hybrid vehicles. The efficiency levels for car models sold in Korea, including hybrid ones, were measured using the recently developed discrete additive data envelopment analysis (DEA) model that reflects consumer preference. The result of the analysis shows that current hybrid vehicles on the market are still at lower competitive advantage than traditional car models with conventional combustion engines and we can suggest a mix of incentive policies to promote the competitiveness of hybrid vehicles. In addition, we also identify two distinctive trends of hybrid vehicle development: environment-oriented hybrid vehicles and performance-oriented hybrid vehicles. It implies that the government should take account of development trends of hybrid vehicles to achieve the policy goals in designing support schemes and automobile companies that are willing to develop hybrid vehicles can also gain some insights for making strategic decisions. (author)
Efficiency in the Worst Production Situation Using Data Envelopment Analysis
Directory of Open Access Journals (Sweden)
Md. Kamrul Hossain
2013-01-01
Full Text Available Data envelopment analysis (DEA measures relative efficiency among the decision making units (DMU without considering noise in data. The least efficient DMU indicates that it is in the worst situation. In this paper, we measure efficiency of individual DMU whenever it losses the maximum output, and the efficiency of other DMUs is measured in the observed situation. This efficiency is the minimum efficiency of a DMU. The concept of stochastic data envelopment analysis (SDEA is a DEA method which considers the noise in data which is proposed in this study. Using bounded Pareto distribution, we estimate the DEA efficiency from efficiency interval. Small value of shape parameter can estimate the efficiency more accurately using the Pareto distribution. Rank correlations were estimated between observed efficiencies and minimum efficiency as well as between observed and estimated efficiency. The correlations are indicating the effectiveness of this SDEA model.
Thin Film Packaging Solutions for High Efficiency OLED Lighting Products
Energy Technology Data Exchange (ETDEWEB)
None
2008-06-30
The objective of the 'Thin Film Packaging Solutions for High Efficiency OLED Lighting Products' project is to demonstrate thin film packaging solutions based on SiC hermetic coatings that, when applied to glass and plastic substrates, support OLED lighting devices by providing longer life with greater efficiency at lower cost than is currently available. Phase I Objective: Demonstrate thin film encapsulated working phosphorescent OLED devices on optical glass with lifetime of 1,000 hour life, CRI greater than 75, and 15 lm/W. Phase II Objective: Demonstrate thin film encapsulated working phosphorescent OLED devices on plastic or glass composite with 25 lm/W, 5,000 hours life, and CRI greater than 80. Phase III Objective: Demonstrate 2 x 2 ft{sup 2} thin film encapsulated working phosphorescent OLED with 40 lm/W, 10,000 hour life, and CRI greater than 85. This report details the efforts of Phase III (Budget Period Three), a fourteen month collaborative effort that focused on optimization of high-efficiency phosphorescent OLED devices and thin-film encapsulation of said devices. The report further details the conclusions and recommendations of the project team that have foundation in all three budget periods for the program. During the conduct of the Thin Film Packaging Solutions for High Efficiency OLED Lighting Products program, including budget period three, the project team completed and delivered the following achievements: (1) a three-year marketing effort that characterized the near-term and longer-term OLED market, identified customer and consumer lighting needs, and suggested prototype product concepts and niche OLED applications lighting that will give rise to broader market acceptance as a source for wide area illumination and energy conservation; (2) a thin film encapsulation technology with a lifetime of nearly 15,000 hours, tested by calcium coupons, while stored at 16 C and 40% relative humidity ('RH'). This encapsulation technology
2010-06-07
... DEPARTMENT OF ENERGY Office of Energy Efficiency and Renewable Energy [Docket Number EERE-BT-PET-0024] Energy Efficiency Program for Consumer Products: Commonwealth of Massachusetts Petition for Exemption From Federal Preemption of Massachusetts' Energy Efficiency Standard for Residential Non...
Strategies of Production Control as Tools of Efficient Management of Production Enterprises
Budynek, Mateusz; Celińska, Elżbieta; Dybikowska, Adrianna; Kozak, Monika; Ratajczak, Joanna; Urban, Jagoda; Materne, Karolina
2016-03-01
The paper discusses the problem of principle methods of production control as a strategy supporting the production system and stimulating efficient solutions in respect management in production enterprises. The article describes MRP, ERP, JIT, KANBAN and TOC methods and focuses on their main goals, principles of functioning as well as benefits resulting from their application. The methods represent two diverse strategies of production control, i.e. pull and push strategies. Push strategies are used when the plans apply to the first and principle part of production and are based on the demand forecasts. Pull strategies are used when all planning decisions apply to the final stage and depend on the actual demand or orders from customers.
STRATEGIES OF PRODUCTION CONTROL AS TOOLS OF EFFICIENT MANAGEMENT OF PRODUCTION ENTERPRISES
Directory of Open Access Journals (Sweden)
Mateusz BUDYNEK
2016-01-01
Full Text Available The paper discusses the problem of principle methods of production control as a strategy supporting the production system and stimulating efficient solutions in respect management in production enterprises. The article describes MRP, ERP, JIT, KANBAN and TOC methods and focuses on their main goals, principles of functioning as well as benefits re-sulting from their application. The methods represent two diverse strategies of production control, i.e. pull and push strategies. Push strategies are used when the plans apply to the first and principle part of production and are based on the demand forecasts. Pull strategies are used when all planning decisions apply to the final stage and depend on the actual demand or orders from customers.
Evaluation of the efficiency of alternative enzyme production technologies
Energy Technology Data Exchange (ETDEWEB)
Albaek, M.O.
2012-03-15
Enzymes are used in an increasing number of industries. The application of enzymes is extending into the production of lignocellulosic ethanol in processes that economically can compete with fossil fuels. Since lignocellulosic ethanol is based on renewable resources it will have a positive impact on for example the emission of green house gasses. Cellulases and hemi-cellulases are used for enzymatic hydrolysis of pretreated lignocellulosic biomass, and fermentable sugars are released upon the enzymatic process. Even though many years of research has decreased the amount of enzyme needed in the process, the cost of enzymes is still considered a bottleneck in the economic feasibility of lignocellulose utilization. The purpose of this project was to investigate and compare different technologies for production of these enzymes. The filamentous fungus Trichoderma reesei is currently used for industrial production of cellulases and hemi-cellulases. The aim of the thesis was to use modeling tools to identify alternative technologies that have higher energy or raw material efficiency than the current technology. The enzyme production by T. reesei was conducted as an aerobic fed-batch fermentation. The process was carried out in pilot scale stirred tank reactors and based on a range of different process conditions, a process model was constructed which satisfactory described the course of fermentation. The process was governed by the rate limiting mass transfer of oxygen from the gas to the liquid phase. During fermentation, filamentous growth of the fungus lead to increased viscosity which hindered mass transfer. These mechanisms were described by a viscosity model based on the biomass concentration of the fermentation broth and a mass transfer correlation that incorporated a viscosity term. An analysis of the uncertainty and sensitivity of the model indicated the biological parameters to be responsible for most of the model uncertainty. A number of alternative
Indian Academy of Sciences (India)
Enthalpy–entropy compensation is the name given to the correlation sometimes observed between the estimates of the enthalpy and entropy of a reaction obtained from temperature-dependence data. Although the mainly artefactual nature of this correlation has been known for many years, the subject enjoys periodical ...
Indian Academy of Sciences (India)
During the process of ageing, the balance shifts in the direction of anarchy. Death is ... tion of life and the laws of statistieal physics and entropy, both of which ... capable of doing work. ... defined by Ludwig Boltzmann in 1877, the entropy of the.
Energy Technology Data Exchange (ETDEWEB)
Bao, Ning [Institute for Quantum Information and Matter, California Institute of Technology,Pasadena, CA 91125 (United States); Walter Burke Institute for Theoretical Physics, California Institute of Technology,452-48, Pasadena, CA 91125 (United States); Nezami, Sepehr [Stanford Institute for Theoretical Physics, Stanford University,Stanford, CA 94305 (United States); Ooguri, Hirosi [Walter Burke Institute for Theoretical Physics, California Institute of Technology,452-48, Pasadena, CA 91125 (United States); Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo,Kashiwa 277-8583 (Japan); Stoica, Bogdan [Walter Burke Institute for Theoretical Physics, California Institute of Technology,452-48, Pasadena, CA 91125 (United States); Sully, James [Theory Group, SLAC National Accelerator Laboratory, Stanford University,Menlo Park, CA 94025 (United States); Walter, Michael [Stanford Institute for Theoretical Physics, Stanford University,Stanford, CA 94305 (United States)
2015-09-21
We initiate a systematic enumeration and classification of entropy inequalities satisfied by the Ryu-Takayanagi formula for conformal field theory states with smooth holographic dual geometries. For 2, 3, and 4 regions, we prove that the strong subadditivity and the monogamy of mutual information give the complete set of inequalities. This is in contrast to the situation for generic quantum systems, where a complete set of entropy inequalities is not known for 4 or more regions. We also find an infinite new family of inequalities applicable to 5 or more regions. The set of all holographic entropy inequalities bounds the phase space of Ryu-Takayanagi entropies, defining the holographic entropy cone. We characterize this entropy cone by reducing geometries to minimal graph models that encode the possible cutting and gluing relations of minimal surfaces. We find that, for a fixed number of regions, there are only finitely many independent entropy inequalities. To establish new holographic entropy inequalities, we introduce a combinatorial proof technique that may also be of independent interest in Riemannian geometry and graph theory.
International Nuclear Information System (INIS)
Bao, Ning; Nezami, Sepehr; Ooguri, Hirosi; Stoica, Bogdan; Sully, James; Walter, Michael
2015-01-01
We initiate a systematic enumeration and classification of entropy inequalities satisfied by the Ryu-Takayanagi formula for conformal field theory states with smooth holographic dual geometries. For 2, 3, and 4 regions, we prove that the strong subadditivity and the monogamy of mutual information give the complete set of inequalities. This is in contrast to the situation for generic quantum systems, where a complete set of entropy inequalities is not known for 4 or more regions. We also find an infinite new family of inequalities applicable to 5 or more regions. The set of all holographic entropy inequalities bounds the phase space of Ryu-Takayanagi entropies, defining the holographic entropy cone. We characterize this entropy cone by reducing geometries to minimal graph models that encode the possible cutting and gluing relations of minimal surfaces. We find that, for a fixed number of regions, there are only finitely many independent entropy inequalities. To establish new holographic entropy inequalities, we introduce a combinatorial proof technique that may also be of independent interest in Riemannian geometry and graph theory.
Efficient production of free fatty acids from soybean meal carbohydrates.
Wang, Dan; Thakker, Chandresh; Liu, Ping; Bennett, George N; San, Ka-Yiu
2015-11-01
Conversion of biomass feedstock to chemicals and fuels has attracted increasing attention recently. Soybean meal, containing significant quantities of carbohydrates, is an inexpensive renewable feedstock. Glucose, galactose, and fructose can be obtained by enzymatic hydrolysis of soluble carbohydrates of soybean meal. Free fatty acids (FFAs) are valuable molecules that can be used as precursors for the production of fuels and other value-added chemicals. In this study, free fatty acids were produced by mutant Escherichia coli strains with plasmid pXZ18Z (carrying acyl-ACP thioesterase (TE) and (3R)-hydroxyacyl-ACP dehydratase) using individual sugars, sugar mixtures, and enzymatic hydrolyzed soybean meal extract. For individual sugar fermentations, strain ML211 (MG1655 fadD(-) fabR(-) )/pXZ18Z showed the best performance, which produced 4.22, 3.79, 3.49 g/L free fatty acids on glucose, fructose, and galactose, respectively. While the strain ML211/pXZ18Z performed the best with individual sugars, however, for sugar mixture fermentation, the triple mutant strain XZK211 (MG1655 fadD(-) fabR(-) ptsG(-) )/pXZ18Z with an additional deletion of ptsG encoding the glucose-specific transporter, functioned the best due to relieved catabolite repression. This strain produced approximately 3.18 g/L of fatty acids with a yield of 0.22 g fatty acids/g total sugar. Maximum free fatty acids production of 2.78 g/L with a high yield of 0.21 g/g was achieved using soybean meal extract hydrolysate. The results suggested that soybean meal carbohydrates after enzymatic treatment could serve as an inexpensive feedstock for the efficient production of free fatty acids. © 2015 Wiley Periodicals, Inc.
Entropy and Digital Installation
Directory of Open Access Journals (Sweden)
Susan Ballard
2005-01-01
Full Text Available This paper examines entropy as a process which introduces ideas of distributed materiality to digital installation. Beginning from an analysis of entropy as both force and probability measure within information theory and it’s extension in Ruldof Arnheim’s text ‘Entropy and Art” it develops an argument for the positive rather thannegative forces of entropy. The paper centres on a discussion of two recent works by New Zealand artists Ronnie van Hout (“On the Run”, Wellington City Gallery, NZ, 2004 and Alex Monteith (“Invisible Cities”, Physics Room Contemporary Art Space, Christchurch, NZ, 2004. Ballard suggests that entropy, rather than being a hindrance to understanding or a random chaotic force, discloses a necessary and material politics of noise present in digital installation.
Crop and soil specific N and P efficiency and productivity in Finland
Directory of Open Access Journals (Sweden)
S. BÄCKMAN
2008-12-01
Full Text Available This paper estimates a stochastic production frontier based on experimental data of cereals production in Finland over the period 1977-1994. The estimates of the production frontier are used to analyze nitrogen and phosphorous productivity and efficiency differences between soils and crops. For this input specific efficiencies are calculated. The results can be used to recognize relations between fertilizer management and soil types as well as to learn where certain soil types and crop combinations require special attention to fertilization strategy. The combination of inputs as designed by the experiment shows significant inefficiencies for both N and P. The measures of mineral productivity and efficiency indicate that clay is the most mineral efficient and productive soil while silt and organic soils are the least efficient and productive soils. Furthermore, a positive correlation is found between mineral productivity and efficiency. The results indicate that substantial technical efficiency differences between different experiments prevail.;
Linear entropy in quantum phase space
International Nuclear Information System (INIS)
Rosales-Zarate, Laura E. C.; Drummond, P. D.
2011-01-01
We calculate the quantum Renyi entropy in a phase-space representation for either fermions or bosons. This can also be used to calculate purity and fidelity, or the entanglement between two systems. We show that it is possible to calculate the entropy from sampled phase-space distributions in normally ordered representations, although this is not possible for all quantum states. We give an example of the use of this method in an exactly soluble thermal case. The quantum entropy cannot be calculated at all using sampling methods in classical symmetric (Wigner) or antinormally ordered (Husimi) phase spaces, due to inner-product divergences. The preferred method is to use generalized Gaussian phase-space methods, which utilize a distribution over stochastic Green's functions. We illustrate this approach by calculating the reduced entropy and entanglement of bosonic or fermionic modes coupled to a time-evolving, non-Markovian reservoir.
Linear entropy in quantum phase space
Energy Technology Data Exchange (ETDEWEB)
Rosales-Zarate, Laura E. C.; Drummond, P. D. [Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122 (Australia)
2011-10-15
We calculate the quantum Renyi entropy in a phase-space representation for either fermions or bosons. This can also be used to calculate purity and fidelity, or the entanglement between two systems. We show that it is possible to calculate the entropy from sampled phase-space distributions in normally ordered representations, although this is not possible for all quantum states. We give an example of the use of this method in an exactly soluble thermal case. The quantum entropy cannot be calculated at all using sampling methods in classical symmetric (Wigner) or antinormally ordered (Husimi) phase spaces, due to inner-product divergences. The preferred method is to use generalized Gaussian phase-space methods, which utilize a distribution over stochastic Green's functions. We illustrate this approach by calculating the reduced entropy and entanglement of bosonic or fermionic modes coupled to a time-evolving, non-Markovian reservoir.
Improving The Efficiency Of Ammonia Electrolysis For Hydrogen Production
Palaniappan, Ramasamy
Given the abundance of ammonia in domestic and industrial wastes, ammonia electrolysis is a promising technology for remediation and distributed power generation in a clean and safe manner. Efficiency has been identified as one of the key issues that require improvement in order for the technology to enter the market phase. Therefore, this research was performed with the aim of improving the efficiency of hydrogen production by finding alternative materials for the cathode and electrolyte. 1. In the presence of ammonia the activity for hydrogen evolution reaction (HER) followed the trend Rh>Pt>Ru>Ni. The addition of ammonia resulted in lower rates for HER for Pt, Ru, and Ni, which have been attributed to competition from the ammonia adsorption reaction. 2. The addition of ammonia offers insight into the role of metal-hydrogen underpotential deposition (M-Hupd) on HER kinetics. In addition to offering competition via ammonia adsorption it resulted in fewer and weaker M-Hupd bonds for all metals. This finding substantiates the theory that M-Hupd bonds favor HER on Pt electrocatalyst. However, for Rh results suggest that M-Hupd bond may hinder the HER. In addition, the presence of unpaired valence shell electrons is suggested to provide higher activity for HER in the presence of ammonia. 3. Bimetals PtxM1-x (M = Ir, Ru, Rh, and Ni) offered lower overpotentials for HER compared to the unalloyed metals in the presence of ammonia. The activity of HER in the presence of ammonia follows the trend Pt-Ir>Pt-Rh>Pt-Ru>Pt-Ni. The higher activity of HER is attributed to the synergistic effect of the alloy, where ammonia adsorbs onto the more electropositive alloying metal leaving Pt available for Hupd formation and HER to take place. Additionally, this supports the theory that the presence of a higher number of unpaired electrons favors the HER in the presence of ammonia. 4. Potassium polyacrylate (PAA-K) was successfully used as a substitute for aqueous KOH for ammonia
Nonsymmetric entropy I: basic concepts and results
Liu, Chengshi
2006-01-01
A new concept named nonsymmetric entropy which generalizes the concepts of Boltzman's entropy and shannon's entropy, was introduced. Maximal nonsymmetric entropy principle was proven. Some important distribution laws were derived naturally from maximal nonsymmetric entropy principle.
Entanglement entropy and nonabelian gauge symmetry
International Nuclear Information System (INIS)
Donnelly, William
2014-01-01
Entanglement entropy has proven to be an extremely useful concept in quantum field theory. Gauge theories are of particular interest, but for these systems the entanglement entropy is not clearly defined because the physical Hilbert space does not factor as a tensor product according to regions of space. Here we review a definition of entanglement entropy that applies to abelian and nonabelian lattice gauge theories. This entanglement entropy is obtained by embedding the physical Hilbert space into a product of Hilbert spaces associated to regions with boundary. The latter Hilbert spaces include degrees of freedom on the entangling surface that transform like surface charges under the gauge symmetry. These degrees of freedom are shown to contribute to the entanglement entropy, and the form of this contribution is determined by the gauge symmetry. We test our definition using the example of two-dimensional Yang–Mills theory, and find that it agrees with the thermal entropy in de Sitter space, and with the results of the Euclidean replica trick. We discuss the possible implications of this result for more complicated gauge theories, including quantum gravity. (paper)
Entropy of the Mixture of Sources and Entropy Dimension
Smieja, Marek; Tabor, Jacek
2011-01-01
We investigate the problem of the entropy of the mixture of sources. There is given an estimation of the entropy and entropy dimension of convex combination of measures. The proof is based on our alternative definition of the entropy based on measures instead of partitions.
Entropy coherent and entropy convex measures of risk
Laeven, Roger; Stadje, M.A.
2010-01-01
We introduce entropy coherent and entropy convex measures of risk and prove a collection of axiomatic characterization and duality results. We show in particular that entropy coherent and entropy convex measures of risk emerge as negative certainty equivalents in (the regular and a generalized
Entropy coherent and entropy convex measures of risk
Laeven, R.J.A.; Stadje, M.
2013-01-01
We introduce two subclasses of convex measures of risk, referred to as entropy coherent and entropy convex measures of risk. Entropy coherent and entropy convex measures of risk are special cases of φ-coherent and φ-convex measures of risk. Contrary to the classical use of coherent and convex
Entropy Coherent and Entropy Convex Measures of Risk
Laeven, R.J.A.; Stadje, M.A.
2011-01-01
We introduce two subclasses of convex measures of risk, referred to as entropy coherent and entropy convex measures of risk. We prove that convex, entropy convex and entropy coherent measures of risk emerge as certainty equivalents under variational, homothetic and multiple priors preferences,
Ozone decreases soybean productivity and water use efficiency
Betzelberger, A. M.; VanLoocke, A. D.; Ainsworth, E. A.; Bernacchi, C. J.
2011-12-01
The combination of population growth and climate change will increase pressure on agricultural and water resources throughout this century. An additional consequence of this growth is an increase in anthropogenic emissions that lead to the formation of tropospheric ozone (O3), which in concert with climate change, poses a significant threat to human health and nutrition. In addition to being an important greenhouse gas, O3 reduces plant productivity, an effect that has been particularly pronounced in soybean, which provides over half of the world's oilseed production. Plant productivity is linked to feedbacks in the climate system, indirectly through the carbon cycle, as well as directly through the partitioning of radiation into heat and moisture fluxes. Soybean, along with maize, comprises the largest ecosystem in the contiguous U.S. Therefore, changes in productivity and water use under increasing O3 could impact human nutrition as well as the regional climate. Soybean response to increasing O3 concentrations was tested under open-air agricultural conditions at the SoyFACE research site. During the 2009 growing season, eight 20 m diameter FACE plots were exposed to different O3 concentrations, ranging from 40 to 200 ppb. Canopy growth (leaf area index) and physiological measurements of leaf photosynthesis and stomatal conductance were taken regularly throughout the growing season. Canopy fluxes of heat and moisture were measured using the residual energy balance micrometeorological technique. Our results indicate that as O3 increased from 40 to 200 ppb, rates of photosynthesis and stomatal conductance decreased significantly. Further, the seed yield decreased by over 60%, while water use decreased by 30% and the water-use-efficiency (yield/water-use) declined by 50%. The growing season average canopy temperatures increased by 1°C and midday temperatures increased by 2°C compared to the control. Warmer and drier canopies may result in a positive feedback on O3
International Nuclear Information System (INIS)
Baccetti, Valentina; Visser, Matt
2013-01-01
Even if a probability distribution is properly normalizable, its associated Shannon (or von Neumann) entropy can easily be infinite. We carefully analyze conditions under which this phenomenon can occur. Roughly speaking, this happens when arbitrarily small amounts of probability are dispersed into an infinite number of states; we shall quantify this observation and make it precise. We develop several particularly simple, elementary, and useful bounds, and also provide some asymptotic estimates, leading to necessary and sufficient conditions for the occurrence of infinite Shannon entropy. We go to some effort to keep technical computations as simple and conceptually clear as possible. In particular, we shall see that large entropies cannot be localized in state space; large entropies can only be supported on an exponentially large number of states. We are for the time being interested in single-channel Shannon entropy in the information theoretic sense, not entropy in a stochastic field theory or quantum field theory defined over some configuration space, on the grounds that this simple problem is a necessary precursor to understanding infinite entropy in a field theoretic context. (paper)
Black hole thermodynamical entropy
International Nuclear Information System (INIS)
Tsallis, Constantino; Cirto, Leonardo J.L.
2013-01-01
As early as 1902, Gibbs pointed out that systems whose partition function diverges, e.g. gravitation, lie outside the validity of the Boltzmann-Gibbs (BG) theory. Consistently, since the pioneering Bekenstein-Hawking results, physically meaningful evidence (e.g., the holographic principle) has accumulated that the BG entropy S BG of a (3+1) black hole is proportional to its area L 2 (L being a characteristic linear length), and not to its volume L 3 . Similarly it exists the area law, so named because, for a wide class of strongly quantum-entangled d-dimensional systems, S BG is proportional to lnL if d=1, and to L d-1 if d>1, instead of being proportional to L d (d ≥ 1). These results violate the extensivity of the thermodynamical entropy of a d-dimensional system. This thermodynamical inconsistency disappears if we realize that the thermodynamical entropy of such nonstandard systems is not to be identified with the BG additive entropy but with appropriately generalized nonadditive entropies. Indeed, the celebrated usefulness of the BG entropy is founded on hypothesis such as relatively weak probabilistic correlations (and their connections to ergodicity, which by no means can be assumed as a general rule of nature). Here we introduce a generalized entropy which, for the Schwarzschild black hole and the area law, can solve the thermodynamic puzzle. (orig.)
Development of efficient photoreactors for solar hydrogen production
Energy Technology Data Exchange (ETDEWEB)
Huang, Cunping; Yao, Weifeng; T-Raissi, Ali; Muradov, Nazim [University of Central Florida, Florida Solar Energy Center, 1679 Clearlake Road, Cocoa, Fl 32922-5703 (United States)
2011-01-15
The rate of hydrogen evolution from a photocatalytic process depends not only on the activity of a photocatalyst, but also on photoreactor design. Ideally, a photoreactor should be able to absorb the incident light, promoting photocatalytic reactions in an effective manner with minimal photonic losses. There are numerous technical challenges and cost related issues when designing a large-scale photoreactor for hydrogen production. Active stirring of the photocatalyst slurry within a photoreactor is not practical in large-scale applications due to cost related issues. Rather, the design should allow facile self-mixing of the flow field within the photoreactor. In this paper two types of photocatalytic reactor configurations are studied: a batch type design and another involving passive self-mixing of the photolyte. Results show that energy loss from a properly designed photoreactor is mainly due to reflection losses from the photoreactor window. We describe the interplay between the reaction and the photoreactor design parameters as well as effects on the rate of hydrogen evolution. We found that a passive self-mixing of the photolyte is possible. Furthermore, the use of certain engineering polymer films as photoreactor window materials has the potential for substantial cost savings in large-scale applications, with minimal reduction of photon energy utilization efficiency. Eight window materials were tested and the results indicate that Aclar trademark polymer film used as the photoreactor window provides a substantial cost saving over other engineering polymers, especially with respect to fused silica glass at modest hydrogen evolution rates. (author)
Entropy-Based Algorithm for Supply-Chain Complexity Assessment
Directory of Open Access Journals (Sweden)
Boris Kriheli
2018-03-01
Full Text Available This paper considers a graph model of hierarchical supply chains. The goal is to measure the complexity of links between different components of the chain, for instance, between the principal equipment manufacturer (a root node and its suppliers (preceding supply nodes. The information entropy is used to serve as a measure of knowledge about the complexity of shortages and pitfalls in relationship between the supply chain components under uncertainty. The concept of conditional (relative entropy is introduced which is a generalization of the conventional (non-relative entropy. An entropy-based algorithm providing efficient assessment of the supply chain complexity as a function of the SC size is developed.
On the generalized entropy pseudoadditivity for complex systems
International Nuclear Information System (INIS)
Wang, Qiuping A.; Nivanen, Laurent; Le Mehaute, Alain; Pezeril, Michel
2002-01-01
We show that Abe's general pseudoadditivity for entropy prescribed by thermal equilibrium in nonextensive systems holds not only for entropy, but also for energy. The application of this general pseudoadditivity to Tsallis entropy tells us that the factorization of the probability of a composite system into a product of the probabilities of the subsystems is just a consequence of the existence of thermal equilibrium and not due to the independence of the subsystems. (author)
Some remarks on conditional entropy
Nijst, A.G.P.M.
1969-01-01
Using a definition of conditional entropy given by Hanen and Neveu [5, 10, 11] we discuss in this paper some properties of conditional entropy and mean entropy, in particular an integral representation of conditional entropy (§ 2), and the decomposition theorem of the KolmogorovSina¯i invariant (§
DEFF Research Database (Denmark)
Saltini, Rolando; Akkerman, Renzo
2012-01-01
hypothetical improvements of the traceability system within the chocolate production system and supply chain and we illustrate the resulting benefits by using a case study. Based on the case study, we quantify the influence of these improvements on production efficiency and recall size in case of a safety......The primary aim of food traceability is to increase food safety, but traceability systems can also bring other benefits to production systems and supply chains. In the literature these benefits are extensively discussed, but studies that quantify them are scarce. In this paper we propose two...... crisis by developing a simulation tool. These results are aimed to illustrate and quantify the additional benefits of traceability information, and could help food industries in deciding whether and how to improve their traceability systems....
Using Data Envelopment Analysis to Measure International Agricultural Efficiency and Productivity
Arnade, Carlos Anthony
1994-01-01
Numerous methods for measuring multifactor productivity have been used by economists. This report uses a recently developed approach, data envlopment analysis, to measure productivity. This method can be used not only to calculate productivity but also to divide productivity measures into indices that measure technical efficiency and technical change. Technical efficiency measures the efficiency with which resources are used. Technical change measures changes in output arising from improved t...
Environmentally friendly disinfectant: Production, disinfectant action and efficiency
Directory of Open Access Journals (Sweden)
Čekerevac Milan I.
2006-01-01
Full Text Available Silver is a known disinfectant from ancient times, and it has been widely used for various purposes: for food and water disinfection, curing of wounds and as a universal antibiotic for a wide spectrum of diseases - until the Second World War and the discovery of penicillin. Until recently, it was assumed that silver, being a heavy metal, was toxic for humans and living beings. However, the newest research provides facts that the usage of silver, even for drinking water disinfection, is benign if it is added in small concentrations (in parts per billion. It has been shown in the newer scientific and technical literature that silver in colloidal form is a powerful (secondary disinfectant for drinking water, that it can be effectively used for the disinfection of water containers including swimming pools, installations in food industry, medicine, etc. Particularly, it has been shown that colloidal silver combined with hydrogen peroxide shows synergism having strong bactericidal and antiviral effects. The combination can be successfully used as a disinfectant in agriculture, food production and medicine. The original electrochemical process of production, the mechanism of physical-chemical reactions in that process and the mechanism of the antiseptic affect of the environmentally friendly disinfectant, based on the synergism of colloidal silver and hydrogen peroxide and the activity of electrochemically activated water, is shown. The starting solution was anolyte, obtained in electrochemical activation by water electrolysis of a highly diluted solution of K-tartarate in demineralized water (5.5-1CT4 M. The problem of electrolysis of very dilute aqueous solutions in membrane cells was particularly treated. It was shown that the efficiency of the electrolysis depends on the competition between the two processes: the rates of the processes of hydrogen and oxygen generation at the electrodes and the process of diffusion of hydrogen and hydroxyl ions
Embryo-transfer twinning and performance efficiency in beef production.
Guerra-Martinez, P; Dickerson, G E; Anderson, G B; Green, R D
1990-12-01
Effects of twinning on efficiency of beef production were estimated from results of bilateral transfer of two Angus x Hereford (AxH) embryos into each of 241 heifers and 84 cows (H, A, HxA or Holstein x H) over 4 yr. Calves were weaned at 180 d and fed either 220 d in a feedlot (1977) or 170 d on forage and 140 d in a feedlot (1978 to 1980). Effects of parity, twinning and sex of calf were estimated as covariates within year-breed of dam. Pregnancy at 45 to 60 d of gestation was 68% in heifers (H) and 74% in cows (C), with 40% single (S) and 60% twin (T) births. Dystocia was 28% in H vs 10% in C (P less than .05), and tended to be less (P greater than .05) for T than S in H. More placentas were retained (P less than .05) for T than for S in both H (35 vs 12%) and C (24 vs 4%). Twin gestations averaged 3 d shorter and subsequent calving intervals 13 d longer (P less than .05), but total calf mortality was slightly higher (P greater than .05). Abortions were 4% in H only. Twinning females lost maternal weight during late gestation (P less than .05) when crowding limited voluntary feed intake, while fetal requirements were 60% higher (P less than .01). Twins increased milk output 25% (P less than .05), but 11% higher feed intake maintained cow weight during lactation. Twinning reduced birth weight 13% and weaning weight 17% (P less than .05), but 400-d feedlot weight only 9% because of compensating feedlot gain. Twins gained 18% faster than S during postweaning 170-d forage feeding, but 5% slower in feedlot to 8% lighter 490-d weight (P less than .05). Assuming 40% higher veterinary and labor costs for twins, estimated integrated herd costs per unit of age-constant output value would be lower for T than for S production by about 24% for marketing either at weaning or at 400 d.
International Nuclear Information System (INIS)
Estes, John; Jensen, Kristan; O’Bannon, Andy; Tsatis, Efstratios; Wrase, Timm
2014-01-01
We study a number of (3+1)- and (2+1)-dimensional defect and boundary conformal field theories holographically dual to supergravity theories. In all cases the defects or boundaries are planar, and the defects are codimension-one. Using holography, we compute the entanglement entropy of a (hemi-)spherical region centered on the defect (boundary). We define defect and boundary entropies from the entanglement entropy by an appropriate background subtraction. For some (3+1)-dimensional theories we find evidence that the defect/boundary entropy changes monotonically under certain renormalization group flows triggered by operators localized at the defect or boundary. This provides evidence that the g-theorem of (1+1)-dimensional field theories generalizes to higher dimensions
Katan, Claudine; Mohite, Aditya D.; Even, Jacky
2018-05-01
Claudine Katan, Aditya D. Mohite and Jacky Even discuss the possible impact of various entropy contributions (stochastic structural fluctuations, anharmonicity and lattice softness) on the optoelectronic properties of halide perovskite materials and devices.
Production and Reproduction Efficiency in Turcana and Ratca Sheep Breeds
Directory of Open Access Journals (Sweden)
Maria Sauer
2017-05-01
Full Text Available Aim of the current comparative study was to evaluate the production and reproduction efficiency in indigenous Turcana and endangered Ratca sheep breeds. Milk yield for the two breeds was on average 68.23±2.33 kg for Ratca ewes and 76.81±2.99 kg in Turcana, respectively, differences between two breeds were significant (p≤0.01. Conception rates were of 97.7±0.87% in Ratca and of 94.8±0.65% in Turcana ewes, respectively, differences were significant between the two flocks (p≤0.05, with the Ratca ewes achieving better fertility rates, compared to their counterparts, the Turcana breed. For prolificacy, the Turcana ewes outperformed significantly (p≤0.01 the Ratca, with an average litter size of 124.2±1.86% and 110.1±1.44%, respectively. Lambs survival and adult ewe culling rates were not affected by the breed factor (p>0.05. Adult ewes body weight when put to ram was significantly (p≤0.05 influenced by the breed, with Turcana ewes having on average 53.8±2.89 kg, compared to 48.0±3.22 kg for the Ratca ewes. The average farm yearly incomes were estimated to be of 150.32 EUR for Ratca ewe-unit and of 144.97 EUR for the Turcana ewe-unit. Although the Turcana outperformed the Ratca ewes, the annual revenue was higher for the Ratca, due to the state conservation subsidy for rare and endangered breeds.
Production of a high-efficiency TILLING population through polyploidization.
Tsai, Helen; Missirian, Victor; Ngo, Kathie J; Tran, Robert K; Chan, Simon R; Sundaresan, Venkatesan; Comai, Luca
2013-04-01
Targeting Induced Local Lesions in Genomes (TILLING) provides a nontransgenic method for reverse genetics that is widely applicable, even in species where other functional resources are missing or expensive to build. The efficiency of TILLING, however, is greatly facilitated by high mutation density. Species vary in the number of mutations induced by comparable mutagenic treatments, suggesting that genetic background may affect the response. Allopolyploid species have often yielded higher mutation density than diploids. To examine the effect of ploidy, we autotetraploidized the Arabidopsis (Arabidopsis thaliana) ecotype Columbia, whose diploid has been used for TILLING extensively, and mutagenized it with 50 mm ethylmethane sulfonate. While the same treatment sterilized diploid Columbia, the tetraploid M1 plants produced good seed. To determine the mutation density, we searched 528 individuals for induced mutations in 15 genes for which few or no knockout alleles were previously available. We constructed tridimensional pools from the genomic DNA of M2 plants, amplified target DNA, and subjected them to Illumina sequencing. The results were analyzed with an improved version of the mutation detection software CAMBa that accepts any pooling scheme. This small population provided a rich resource with approximately 25 mutations per queried 1.5-kb fragment, including on average four severe missense and 1.3 truncation mutations. The overall mutation density of 19.4 mutations Mb(-1) is 4 times that achieved in the corresponding diploid accession, indicating that genomic redundancy engenders tolerance to high mutation density. Polyploidization of diploids will allow the production of small populations, such as less than 2,000, that provide allelic series from knockout to mild loss of function for virtually all genes.
Recommended Ventilation Strategies for Energy-Efficient Production Homes
Energy Technology Data Exchange (ETDEWEB)
Roberson, J.; Brown, R.; Koomey, J.; Warner, J.; Greenberg, S.
1998-12-01
This report evaluates residential ventilation systems for the U.S. Environmental Protection Agency's (EPA's) ENERGY STAR{reg_sign} Homes program and recommends mechanical ventilation strategies for new, low-infiltration, energy-efficient, single-family, ENERGY STAR production (site-built tract) homes in four climates: cold, mixed (cold and hot), hot humid, and hot arid. Our group in the Energy Analysis Department at Lawrence Berkeley National Lab compared residential ventilation strategies in four climates according to three criteria: total annualized costs (the sum of annualized capital cost and annual operating cost), predominant indoor pressure induced by the ventilation system, and distribution of ventilation air within the home. The mechanical ventilation systems modeled deliver 0.35 air changes per hour continuously, regardless of actual infiltration or occupant window-opening behavior. Based on the assumptions and analysis described in this report, we recommend independently ducted multi-port supply ventilation in all climates except cold because this strategy provides the safety and health benefits of positive indoor pressure as well as the ability to dehumidify and filter ventilation air. In cold climates, we recommend that multi-port supply ventilation be balanced by a single-port exhaust ventilation fan, and that builders offer balanced heat-recovery ventilation to buyers as an optional upgrade. For builders who continue to install forced-air integrated supply ventilation, we recommend ensuring ducts are airtight or in conditioned space, installing a control that automatically operates the forced-air fan 15-20 minutes during each hour that the fan does not operate for heating or cooling, and offering ICM forced-air fans to home buyers as an upgrade.
48 CFR 52.223-15 - Energy Efficiency in Energy-Consuming Products.
2010-10-01
... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Energy Efficiency in... Provisions and Clauses 52.223-15 Energy Efficiency in Energy-Consuming Products. As prescribed in 23.206, insert the following clause: Energy Efficiency in Energy-Consuming Products (DEC 2007) (a) Definition. As...
Dias, Weeratilake
1998-01-01
Efficient operation of agricultural credit markets is very important both for the producer as well as for the policy makers. DEA approach is used to calculate productivity analysis which allows decomposition of sources of productivity changes into efficiency and technical change. Measured efficiencies are comparable to most recent parametric studies.
Manfredi; Feix
2000-10-01
The properties of an alternative definition of quantum entropy, based on Wigner functions, are discussed. Such a definition emerges naturally from the Wigner representation of quantum mechanics, and can easily quantify the amount of entanglement of a quantum state. It is shown that smoothing of the Wigner function induces an increase in entropy. This fact is used to derive some simple rules to construct positive-definite probability distributions which are also admissible Wigner functions.
Manfredi, G.; Feix, M. R.
2002-01-01
The properties of an alternative definition of quantum entropy, based on Wigner functions, are discussed. Such definition emerges naturally from the Wigner representation of quantum mechanics, and can easily quantify the amount of entanglement of a quantum state. It is shown that smoothing of the Wigner function induces an increase in entropy. This fact is used to derive some simple rules to construct positive definite probability distributions which are also admissible Wigner functions
Feasible Histories, Maximum Entropy
International Nuclear Information System (INIS)
Pitowsky, I.
1999-01-01
We consider the broadest possible consistency condition for a family of histories, which extends all previous proposals. A family that satisfies this condition is called feasible. On each feasible family of histories we choose a probability measure by maximizing entropy, while keeping the probabilities of commuting histories to their quantum mechanical values. This procedure is justified by the assumption that decoherence increases entropy. Finally, a criterion for identifying the nearly classical families is proposed
Gulamsarwar, Syazwani; Salleh, Zabidin
2017-08-01
The purpose of this paper is to generalize the notions of Adler's topological entropy along with their several fundamental properties. A function f : X → Y is said to be R-map if f-1 (V) is regular open in X for every regular open set V in Y. Thus, we initiated a notion of topological nearly entropy for topological R-dynamical systems which is based on nearly compact relative to the space by using R-map.
Solutions to the Cosmic Initial Entropy Problem without Equilibrium Initial Conditions
Directory of Open Access Journals (Sweden)
Vihan M. Patel
2017-08-01
Full Text Available The entropy of the observable universe is increasing. Thus, at earlier times the entropy was lower. However, the cosmic microwave background radiation reveals an apparently high entropy universe close to thermal and chemical equilibrium. A two-part solution to this cosmic initial entropy problem is proposed. Following Penrose, we argue that the evenly distributed matter of the early universe is equivalent to low gravitational entropy. There are two competing explanations for how this initial low gravitational entropy comes about. (1 Inflation and baryogenesis produce a virtually homogeneous distribution of matter with a low gravitational entropy. (2 Dissatisfied with explaining a low gravitational entropy as the product of a ‘special’ scalar field, some theorists argue (following Boltzmann for a “more natural” initial condition in which the entire universe is in an initial equilibrium state of maximum entropy. In this equilibrium model, our observable universe is an unusual low entropy fluctuation embedded in a high entropy universe. The anthropic principle and the fluctuation theorem suggest that this low entropy region should be as small as possible and have as large an entropy as possible, consistent with our existence. However, our low entropy universe is much larger than needed to produce observers, and we see no evidence for an embedding in a higher entropy background. The initial conditions of inflationary models are as natural as the equilibrium background favored by many theorists.
International Nuclear Information System (INIS)
Lemos, Jose P. S.; Zaslavskii, Oleg B.
2010-01-01
We trace the origin of the black hole entropy S, replacing a black hole by a quasiblack hole. Let the boundary of a static body approach its own gravitational radius, in such a way that a quasihorizon forms. We show that if the body is thermal with the temperature taking the Hawking value at the quasihorizon limit, it follows, in the nonextremal case, from the first law of thermodynamics that the entropy approaches the Bekenstein-Hawking value S=A/4. In this setup, the key role is played by the surface stresses on the quasihorizon and one finds that the entropy comes from the quasihorizon surface. Any distribution of matter inside the surface leads to the same universal value for the entropy in the quasihorizon limit. This can be of some help in the understanding of black hole entropy. Other similarities between black holes and quasiblack holes such as the mass formulas for both objects had been found previously. We also discuss the entropy for extremal quasiblack holes, a more subtle issue.
Efficiency in rice production : evidence from gogounou district in ...
African Journals Online (AJOL)
Thetechnical, allocative and economic efficiencies of rice growing in the District of Gogonou and factors determining the economic efficiency have been analysed with the help of a survey carried out among 150 rice producers randomly sampled during the agricultural year 2005-2006. The data analysis is essentially based ...
On the Conditional Rényi Entropy
S. Fehr (Serge); S. Berens (Stefan)
2014-01-01
htmlabstractThe Rényi entropy of general order unifies the well-known Shannon entropy with several other entropy notions, like the min-entropy or the collision entropy. In contrast to the Shannon entropy, there seems to be no commonly accepted definition for the conditional Rényi entropy: several
Ellipses of constant entropy in the XY spin chain
International Nuclear Information System (INIS)
Franchini, F; Its, A R; Jin, B-Q; Korepin, V E
2007-01-01
Entanglement in the ground state of the XY model on the infinite chain can be measured by the von Neumann entropy of a block of neighbouring spins. We study a double scaling limit: the size of the block is much larger than 1 but much smaller than the length of the whole chain. The entropy of the block has an asymptotic limit in the gapped regimes. We study this limiting entropy as a function of the anisotropy and of the magnetic field. We identify its minima at product states and its divergencies at the quantum phase transitions. We find that the curves of constant entropy are ellipses and hyperbolas, and that they all meet at one point (essential critical point). Depending on the approach to the essential critical point, the entropy can take any value between 0 and ∞. In the vicinity of this point, small changes in the parameters cause large change of the entropy
Economic Efficiency of Maize Production in Yola North Local ...
African Journals Online (AJOL)
user
should include the basic nutrients necessary to meet the needs of the ... economic production and home production, often have damaging ..... economic citizens in Nigeria (Ankroyd and. Doughty, 1984). ... Nutritional Guide. University of.
Production Cost Efficiency and Profitability of Abakaliki Rice in ...
African Journals Online (AJOL)
acer
2014-11-17
Nov 17, 2014 ... positive and significant effect on the total cost of rice production. They were all significant ... failure is experienced due to the flooded rice field. In addition ... for random effects on production beyond the control .... Standard error.
The effect of slaughter weight on pig production efficiency
African Journals Online (AJOL)
Unknown
production costs of a weaner pig, it is possible to determine an optimal ... on growth rate, feed intake, feed conversion ratio, lean meat percentage, production .... versus a classification system neglecting carcass mass is shown in Table 2.
Entropy, non-linearity and hierarchy in ecosystems
Addiscott, T.
2009-04-01
Soil-plant systems are open systems thermodynamically because they exchange both energy and matter with their surroundings. Thus they are properly described by the second and third of the three stages of thermodynamics defined by Prigogine and Stengers (1984). The second stage describes a system in which the flow is linearly related to the force. Such a system tends towards a steady state in which entropy production is minimized, but it depends on the capacity of the system for self-organization. In a third stage system, flow is non-linearly related to force, and the system can move far from equilibrium. This system maximizes entropy production but in so doing facilitates self-organization. The second stage system was suggested earlier to provide a useful analogue of the behaviour of natural and agricultural ecosystems subjected to perturbations, but it needs the capacity for self-organization. Considering an ecosystem as a hierarchy suggests this capacity is provided by the soil population, which releases from dead plant matter nutrients such as nitrate, phosphate and captions needed for growth of new plants and the renewal of the whole ecosystem. This release of small molecules from macromolecules increases entropy, and the soil population maximizes entropy production by releasing nutrients and carbon dioxide as vigorously as conditions allow. In so doing it behaves as a third stage thermodynamic system. Other authors (Schneider and Kay, 1994, 1995) consider that it is in the plants in an ecosystem that maximize entropy, mainly through transpiration, but studies on transpiration efficiency suggest that this is questionable. Prigogine, I. & Stengers, I. 1984. Order out of chaos. Bantam Books, Toronto. Schneider, E.D. & Kay, J.J. 1994. Life as a manifestation of the Second Law of Thermodynamics. Mathematical & Computer Modelling, 19, 25-48. Schneider, E.D. & Kay, J.J. 1995. Order from disorder: The Thermodynamics of Complexity in Biology. In: What is Life: the Next
An analysis of the productivity and technical efficiency of smallholder ...
African Journals Online (AJOL)
2017-01-01
Jan 1, 2017 ... This study used the stochastic frontier production function to analyse the productivity and .... firm Xi is vector of inputs, andb is a vector of production function parameters. ei is an error term ..... regression equations. These are ...
Exergy efficient production, storage and distribution of solar energy
Energy Technology Data Exchange (ETDEWEB)
Sandnes, Bjoernar
2003-07-01
There are two main themes in this thesis. 1) Exergy efficient utilization of solar energy, where the introduction of alternative technologies such as photovoltaic/thermal collectors and phase change energy storage in a low temperature solar system is investigated. 2) The possibility of storing thermal energy in supercooled liquids is investigated. The introductory chapters introduce the concept of exergy, and focus on the use of solar heat as an inherently low quality source for covering low quality demands associated with space heating and hot water. The different stages of solar energy production, storage, and distribution of heat is discussed, with emphasis on exergy relevant issues. With the low temperature solar heating system as background, the introduction of some additional technologies that are investigated. A section of this thesis presents a study of a small scale PV/T collector as a possible component in a low temperature system. In another section the instrumentation that has been built for studies of full-size PV and thermal systems is described, and the possibility of using the PV unit outputs as parameters for controlling the thermal system operation is briefly discussed. It is suggested that the design of the PV/T unit in terms of whether priority should be given to electricity or heat production should be based on how consumption of high quality auxiliary energy is minimized, and not on adding up the combined exergy which is being produced. Solar combisystems require larger heat storage capacities compared to the more common solar hot water systems. Increased volumetric heat storage capacity can be achieved by latent heat storage systems where thermal energy is stored as heat of fusion in phase change materials (PCMs). A section presents a study where spherically encapsulated PCM is incorporated in a solar heat store. Solar combisystems are often complex, and have a relatively large number of interacting components. Another section describes a
Resource use efficiency in small-scale rice production in Nigeria ...
African Journals Online (AJOL)
The production function for rice, elasticity of production, return to scale, marginal productivity and level of efficiency of inputs used in rice production were determined. ... With the exception of fertilizer that was over-utilized, all other inputs were underutilized with ratios of marginal value products to unit prices greater than unity ...
Biomass production efficiency controlled by management in temperate and boreal ecosystems
Campioli, M.; Vicca, S.; Luyssaert, S.; Bilcke, J.; Ceschia, E.; Chapin, F. S., III; Ciais, P.; Fernández-Martínez, M.; Malhi, Y.; Obersteiner, M.; Olefeldt, D.; Papale, D.; Piao, S. L.; Peñuelas, J.; Sullivan, P. F.; Wang, X.; Zenone, T.; Janssens, I. A.
2015-11-01
Plants acquire carbon through photosynthesis to sustain biomass production, autotrophic respiration and production of non-structural compounds for multiple purposes. The fraction of photosynthetic production used for biomass production, the biomass production efficiency, is a key determinant of the conversion of solar energy to biomass. In forest ecosystems, biomass production efficiency was suggested to be related to site fertility. Here we present a database of biomass production efficiency from 131 sites compiled from individual studies using harvest, biometric, eddy covariance, or process-based model estimates of production. The database is global, but dominated by data from Europe and North America. We show that instead of site fertility, ecosystem management is the key factor that controls biomass production efficiency in terrestrial ecosystems. In addition, in natural forests, grasslands, tundra, boreal peatlands and marshes, biomass production efficiency is independent of vegetation, environmental and climatic drivers. This similarity of biomass production efficiency across natural ecosystem types suggests that the ratio of biomass production to gross primary productivity is constant across natural ecosystems. We suggest that plant adaptation results in similar growth efficiency in high- and low-fertility natural systems, but that nutrient influxes under managed conditions favour a shift to carbon investment from the belowground flux of non-structural compounds to aboveground biomass.
An entropy generation metric for non-energy systems assessments
International Nuclear Information System (INIS)
Sekulic, Dusan P.
2009-01-01
Processes in non-energy systems have not been as frequent a subject of sustainability studies based on Thermodynamics as have processes in energy systems. This paper offers insight into thermodynamic thinking devoted to selection of a sustainability energy-related metric based on entropy balancing of a non-energy system. An underlying objective in this sustainability oriented study is product quality involving thermal processing during manufacturing vs. resource utilization (say, energy). The product quality for the considered family of materials processing for manufacturing is postulated as inherently controlled by the imposed temperature non-uniformity margins. These temperature non-uniformities can be converted into a thermodynamic metric which can be related to either destruction of exergy of the available resource or, on a more fundamental level of process quality, to entropy generation inherent to the considered manufacturing system. Hence, a manufacturing system can be considered as if it were an energy system, although in the later case the system objective would be quite different. In a non-energy process, a metric may indicate the level of perfection of the process (not necessarily energy efficiency) and may be related to the sustainability footprint or, as advocated in this paper, it may be related to product quality. Controlled atmosphere brazing (CAB) of aluminum, a state-of-the-art manufacturing process involving mass production of compact heat exchangers for automotive, aerospace and process industries, has been used as an example.
Maximum entropy decomposition of quadrupole mass spectra
International Nuclear Information System (INIS)
Toussaint, U. von; Dose, V.; Golan, A.
2004-01-01
We present an information-theoretic method called generalized maximum entropy (GME) for decomposing mass spectra of gas mixtures from noisy measurements. In this GME approach to the noisy, underdetermined inverse problem, the joint entropies of concentration, cracking, and noise probabilities are maximized subject to the measured data. This provides a robust estimation for the unknown cracking patterns and the concentrations of the contributing molecules. The method is applied to mass spectroscopic data of hydrocarbons, and the estimates are compared with those received from a Bayesian approach. We show that the GME method is efficient and is computationally fast
Resource-Use Efficiency in Rice Production Under Small Scale ...
African Journals Online (AJOL)
acer
specific objectives of the study were to determine resource use efficiency, describe ... economic level. ... this key variable with a view to stepping ... focused on small-scale irrigation systems for ... farmers were assumed to be operating under.
Productive efficiency of tea industry: A stochastic frontier approach
African Journals Online (AJOL)
USER
2010-06-21
Jun 21, 2010 ... Key words: Technical efficiency, stochastic frontier, translog ... present low performance of the tea industry in Bangladesh. ... The Technical inefficiency effect .... administrative, technical, clerical, sales and purchase staff.
Maximum herd efficiency in meat production II. The influence of ...
African Journals Online (AJOL)
surface in terms of plots of total efficiency against percentages of mature body .... Dickerson (1978) shows that, for cattle and sheep, the energy .... protein metabolism. ... metric slope b is a scale-free parameter is convenient and .... Simulation.
Entropy of balance - some recent results
Directory of Open Access Journals (Sweden)
Laxåback Gerd
2010-07-01
Full Text Available Abstract Background Entropy when applied to biological signals is expected to reflect the state of the biological system. However the physiological interpretation of the entropy is not always straightforward. When should high entropy be interpreted as a healthy sign, and when as marker of deteriorating health? We address this question for the particular case of human standing balance and the Center of Pressure data. Methods We have measured and analyzed balance data of 136 participants (young, n = 45; elderly, n = 91 comprising in all 1085 trials, and calculated the Sample Entropy (SampEn for medio-lateral (M/L and anterior-posterior (A/P Center of Pressure (COP together with the Hurst self-similariy (ss exponent α using Detrended Fluctuation Analysis (DFA. The COP was measured with a force plate in eight 30 seconds trials with eyes closed, eyes open, foam, self-perturbation and nudge conditions. Results 1 There is a significant difference in SampEn for the A/P-direction between the elderly and the younger groups Old > young. 2 For the elderly we have in general A/P > M/L. 3 For the younger group there was no significant A/P-M/L difference with the exception for the nudge trials where we had the reverse situation, A/P Eyes Open. 5 In case of the Hurst ss-exponent we have for the elderly, M/L > A/P. Conclusions These results seem to be require some modifications of the more or less established attention-constraint interpretation of entropy. This holds that higher entropy correlates with a more automatic and a less constrained mode of balance control, and that a higher entropy reflects, in this sense, a more efficient balancing.
Eco-efficiency analysis methodology on the example of the chosen polyolefins production
K. Czaplicka-Kolarz; D. Burchart-Korol; P. Krawczyk
2010-01-01
the chosen polyolefins production. The article presents also main tools of eco-efficiency analysis: Life Cycle Assessment (LCA) and Net Present Value (NPV).Design/methodology/approach: On the basis of LCA and NPV of high density polyethylene (HDPE) and low density polyethylene (LDPE) production, eco-efficiency analysis is conducted.Findings: In this article environmental and economic performance of the chosen polyolefins production was presented. The basis phases of eco-efficiency methodology...
Phuong, Vu Hung
2018-03-01
This research applies Data Envelopment Analysis (DEA) approach to analyze Total Factor Productivity (TFP) and efficiency changes in Vietnam coal mining industry from 2007 to 2013. The TFP of Vietnam coal mining companies decreased due to slow technological progress and unimproved efficiency. The decadence of technical efficiency in many enterprises proved that the coal mining industry has a large potential to increase productivity through technical efficiency improvement. Enhancing human resource training, technology and research & development investment could help the industry to improve efficiency and productivity in Vietnam coal mining industry.
SWEET CORN FARMING: THE EFFECT OF PRODUCTION FACTOR, EFFICIENCY AND RETURN TO SCALE
Directory of Open Access Journals (Sweden)
Dwijatenaya I.B.M.A.
2017-10-01
Full Text Available This research aims to determine the effect of production factors on the sweet corn production, the efficiency of sweet corn farming, and the return to scale of sweet corn production. The sampling technique was taken by proportionate stratified random sampling method with the sample number of 57 people while the analyzer used was the program of Frointer 4.1c. The results show that the production factors of the land farm, seed, and fertilizer have a positive and significant effect on sweet corn production. On the other hand, labor production factors have a positive but not significant effect on sweet corn production. It also found that technical efficiency, price efficiency, and economic efficiency of sweet corn farming in Muara Wis Sub-district of Kutai Kartanegara Regency are not efficient yet. The return to scale of sweet corn yield has an increasing return to scale condition.
Overview and theory relating to the concepts of competitiveness, efficiency and productivity
Latruffe, Laure
2017-01-01
This is a brief overview and theory relating to the concepts of competitiveness, efficiency and productivity: concept of competitiveness, measurement of competitiveness, determinants of competitiveness.
Lawson, L G; Bruun, J; Coelli, T; Agger, J F; Lund, M
2004-01-01
Relationships of various reproductive disorders and milk production performance of Danish dairy farms were investigated. A stochastic frontier production function was estimated using data collected in 1998 from 514 Danish dairy farms. Measures of farm-level milk production efficiency relative to this production frontier were obtained, and relationships between milk production efficiency and the incidence risk of reproductive disorders were examined. There were moderate positive relationships between milk production efficiency and retained placenta, induction of estrus, uterine infections, ovarian cysts, and induction of birth. Inclusion of reproductive management variables showed that these moderate relationships disappeared, but directions of coefficients for almost all those variables remained the same. Dystocia showed a weak negative correlation with milk production efficiency. Farms that were mainly managed by young farmers had the highest average efficiency scores. The estimated milk losses due to inefficiency averaged 1142, 488, and 256 kg of energy-corrected milk per cow, respectively, for low-, medium-, and high-efficiency herds. It is concluded that the availability of younger cows, which enabled farmers to replace cows with reproductive disorders, contributed to high cow productivity in efficient farms. Thus, a high replacement rate more than compensates for the possible negative effect of reproductive disorders. The use of frontier production and efficiency/inefficiency functions to analyze herd data may enable dairy advisors to identify inefficient herds and to simulate the effect of alternative management procedures on the individual herd's efficiency.
Energy Technology Data Exchange (ETDEWEB)
Baptista, Tatyana S.; Batista, Vanessa; Gomes, Antonio; Matsuda, Margareth; Fukumori, Neuza; Araujo, Elaine B. de, E-mail: tsbaptista@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)
2013-07-01
A great challenge in the radiopharmaceuticals production is to fulfill the Good Manufacturing Practices (GMPs), involving the validation of process and of all supporting activities such as cleaning and sanitization. The increasingly strict requirements for quality assurance system, with several norms and normative resolutions has led to a constant concern with programs and cleaning validation in pharmaceutical production. The main goal of GMP is to reduce risks inherent to pharmaceutical production, that is to reduce product contamination with microorganisms and cross-contamination. The basic requirements to prevent contamination is the development and implementation of efficient cleaning programs. In the case of clean rooms for the production of injectable radiopharmaceuticals, the requirement for cleaning programs is evidently higher due to the characteristics of these areas with hot cells for radioactive materials, where sterile radiopharmaceuticals are manipulated and distributed before administration to patients just after minutes or hours of its preparation. In the Radiopharmacy Department at IPEN it was established a cleaning program for clean rooms and hot cells using a hydrogen peroxide solution (20% proxitane alfa). The objective of this work was to assess effectiveness of this cleaning agent in reducing and/or eliminating microbial load in the clean rooms and equipment to acceptable levels in accordance with the current legislation. The analysis was conducted using results of the environmental monitoring program with and settling contact plates in clean rooms after the cleaning procedures. Furthermore, it was possible to evaluate the action of the sanitizing agent on the microbial population on the surface of equipment and clean rooms. It was also evaluated the best way to accomplish the cleaning program considering the dosimetric factor in each production process, as the main concern of pharmaceutical companies is the microbiological contamination, in
International Nuclear Information System (INIS)
Baptista, Tatyana S.; Batista, Vanessa; Gomes, Antonio; Matsuda, Margareth; Fukumori, Neuza; Araujo, Elaine B. de
2013-01-01
A great challenge in the radiopharmaceuticals production is to fulfill the Good Manufacturing Practices (GMPs), involving the validation of process and of all supporting activities such as cleaning and sanitization. The increasingly strict requirements for quality assurance system, with several norms and normative resolutions has led to a constant concern with programs and cleaning validation in pharmaceutical production. The main goal of GMP is to reduce risks inherent to pharmaceutical production, that is to reduce product contamination with microorganisms and cross-contamination. The basic requirements to prevent contamination is the development and implementation of efficient cleaning programs. In the case of clean rooms for the production of injectable radiopharmaceuticals, the requirement for cleaning programs is evidently higher due to the characteristics of these areas with hot cells for radioactive materials, where sterile radiopharmaceuticals are manipulated and distributed before administration to patients just after minutes or hours of its preparation. In the Radiopharmacy Department at IPEN it was established a cleaning program for clean rooms and hot cells using a hydrogen peroxide solution (20% proxitane alfa). The objective of this work was to assess effectiveness of this cleaning agent in reducing and/or eliminating microbial load in the clean rooms and equipment to acceptable levels in accordance with the current legislation. The analysis was conducted using results of the environmental monitoring program with and settling contact plates in clean rooms after the cleaning procedures. Furthermore, it was possible to evaluate the action of the sanitizing agent on the microbial population on the surface of equipment and clean rooms. It was also evaluated the best way to accomplish the cleaning program considering the dosimetric factor in each production process, as the main concern of pharmaceutical companies is the microbiological contamination, in
Bianconi, Ginestra
2009-03-01
In this paper we generalize the concept of random networks to describe network ensembles with nontrivial features by a statistical mechanics approach. This framework is able to describe undirected and directed network ensembles as well as weighted network ensembles. These networks might have nontrivial community structure or, in the case of networks embedded in a given space, they might have a link probability with a nontrivial dependence on the distance between the nodes. These ensembles are characterized by their entropy, which evaluates the cardinality of networks in the ensemble. In particular, in this paper we define and evaluate the structural entropy, i.e., the entropy of the ensembles of undirected uncorrelated simple networks with given degree sequence. We stress the apparent paradox that scale-free degree distributions are characterized by having small structural entropy while they are so widely encountered in natural, social, and technological complex systems. We propose a solution to the paradox by proving that scale-free degree distributions are the most likely degree distribution with the corresponding value of the structural entropy. Finally, the general framework we present in this paper is able to describe microcanonical ensembles of networks as well as canonical or hidden-variable network ensembles with significant implications for the formulation of network-constructing algorithms.
Enzyme catalysis by entropy without Circe effect.
Kazemi, Masoud; Himo, Fahmi; Åqvist, Johan
2016-03-01
Entropic effects have often been invoked to explain the extraordinary catalytic power of enzymes. In particular, the hypothesis that enzymes can use part of the substrate-binding free energy to reduce the entropic penalty associated with the subsequent chemical transformation has been very influential. The enzymatic reaction of cytidine deaminase appears to be a distinct example. Here, substrate binding is associated with a significant entropy loss that closely matches the activation entropy penalty for the uncatalyzed reaction in water, whereas the activation entropy for the rate-limiting catalytic step in the enzyme is close to zero. Herein, we report extensive computer simulations of the cytidine deaminase reaction and its temperature dependence. The energetics of the catalytic reaction is first evaluated by density functional theory calculations. These results are then used to parametrize an empirical valence bond description of the reaction, which allows efficient sampling by molecular dynamics simulations and computation of Arrhenius plots. The thermodynamic activation parameters calculated by this approach are in excellent agreement with experimental data and indeed show an activation entropy close to zero for the rate-limiting transition state. However, the origin of this effect is a change of reaction mechanism compared the uncatalyzed reaction. The enzyme operates by hydroxide ion attack, which is intrinsically associated with a favorable activation entropy. Hence, this has little to do with utilization of binding free energy to pay the entropic penalty but rather reflects how a preorganized active site can stabilize a reaction path that is not operational in solution.
Methodical Approach to Diagnostics of Efficiency of Production Economic Activity of an Enterprise
Directory of Open Access Journals (Sweden)
Zhukov Andrii V.
2014-03-01
Full Text Available The article offers developments of a methodical approach to diagnostics of efficiency of production economic activity of an enterprise, which, unlike the existing ones, is realised through the following stages: analysis of the enterprise external environment; analysis of the enterprise internal environment; identification of components of efficiency of production economic activity for carrying out complex diagnostics by the following directions: efficiency of subsystems of the enterprise production economic activity, efficiency of use of separate types of resources and socio-economic efficiency; scorecard formation; study of tendencies of change of indicators; identification of cause-effect dependencies between the main components of efficiency for diagnosing reasons of its level; diagnosing deviations of indicator values from their optimal values; development of a managerial decision on preserving and increasing efficiency of production economic activity of the enterprise.
Efficient production of long-lived ultracold Sr2 molecules
Ciamei, Alessio; Bayerle, Alex; Chen, Chun-Chia; Pasquiou, Benjamin; Schreck, Florian
2017-07-01
We associate Sr atom pairs on sites of a Mott insulator optically and coherently into weakly bound ground-state molecules, achieving an efficiency above 80%. This efficiency is 2.5 times higher than in our previous work [S. Stellmer, B. Pasquiou, R. Grimm, and F. Schreck, Phys. Rev. Lett. 109, 115302 (2012), 10.1103/PhysRevLett.109.115302] and obtained through two improvements. First, the lifetime of the molecules is increased beyond one minute by using an optical lattice wavelength that is further detuned from molecular transitions. Second, we compensate undesired dynamic light shifts that occur during the stimulated Raman adiabatic passage (STIRAP) used for molecule association. We also characterize and model STIRAP, providing insights into its limitations. Our work shows that significant molecule association efficiencies can be achieved even for atomic species or mixtures that lack Feshbach resonances suitable for magnetoassociation.
Halsema, van G.E.; Vincent, L.F.
2012-01-01
Growing water scarcity and increasing demands for agricultural products generate much debate about improving the agricultural sector's water use efficiency and productivity. Agricultural engineering traditions feed this debate with notions such as agricultural yield gaps and low water use
Resources Use Efficiency In Food Crop Production In Ekiti State ...
African Journals Online (AJOL)
Marginal value productivity of resources were computed and compared with the acquisition/prices of these resources. Result of regression analysis indicates that farm size, fertilizer and purchased inputs were significant inputs that accounted for variation in the output of food crops. The Marginal Value Product (MVP) of all ...
A resource efficiency assessment of the industrial mushroom production chain
Zisopoulos, Filippos K.; Becerra Ramírez, Henry A.; Goot, van der Atze Jan; Boom, Remko M.
2016-01-01
We compare the exergetic performance of a conventional industrial mushroom production chain with a mushroom production chain where part of the compost waste is recycled and reused as raw material. The critical exergy loss points (CEPs) identified are the cooking-out process of the spent mushroom
Ranking production units according to marginal efficiency contribution
DEFF Research Database (Denmark)
Ghiyasi, Mojtaba; Hougaard, Jens Leth
League tables associated with various forms of service activities from schools to hospitals illustrate the public need for ranking institutions by their productive performance. We present a new method for ranking production units which is based on each units marginal contribution to the technical...
Nitrogen and Phosphorus Use Efficiencies in Dairy Production in China
Bai, Z.H.; Ma, L.; Oenema, O.; Chen, Q.; Zhang, F.S.
2013-01-01
Milk production has greatly increased in China recently, with significant impacts on the cycling of nitrogen (N) and phosphorus (P). However, nutrient flows within the changing dairy production system are not well quantified. The aim of this study was to increase the quantitative understanding of N
Buy Energy-Efficient Products: A Guide for Federal Purchasers and Specifiers
Energy Technology Data Exchange (ETDEWEB)
2016-07-01
In a single year, energy-efficient product purchases could save the federal government almost a half billion dollars worth of energy. By purchasing products that exceed the minimum required efficiency levels, buyers can save the government even more energy and money. Federal employees and contractors must take an active role in ensuring that the government receives products that meet efficiency requirements. This document provides an overview of product purchasing requirements and shows you how to write compliant contracts, find funding, and confirm product compliance.
A gravitational entropy proposal
International Nuclear Information System (INIS)
Clifton, Timothy; Tavakol, Reza; Ellis, George F R
2013-01-01
We propose a thermodynamically motivated measure of gravitational entropy based on the Bel–Robinson tensor, which has a natural interpretation as the effective super-energy–momentum tensor of free gravitational fields. The specific form of this measure differs depending on whether the gravitational field is Coulomb-like or wave-like, and reduces to the Bekenstein–Hawking value when integrated over the interior of a Schwarzschild black hole. For scalar perturbations of a Robertson–Walker geometry we find that the entropy goes like the Hubble weighted anisotropy of the gravitational field, and therefore increases as structure formation occurs. This is in keeping with our expectations for the behaviour of gravitational entropy in cosmology, and provides a thermodynamically motivated arrow of time for cosmological solutions of Einstein’s field equations. It is also in keeping with Penrose’s Weyl curvature hypothesis. (paper)
Parametric Bayesian Estimation of Differential Entropy and Relative Entropy
Gupta; Srivastava
2010-01-01
Given iid samples drawn from a distribution with known parametric form, we propose the minimization of expected Bregman divergence to form Bayesian estimates of differential entropy and relative entropy, and derive such estimators for the uniform, Gaussian, Wishart, and inverse Wishart distributions. Additionally, formulas are given for a log gamma Bregman divergence and the differential entropy and relative entropy for the Wishart and inverse Wishart. The results, as always with Bayesian est...
Measuring Eco-efficiency of Production with Data Envelopment Analysis
Kuosmanen, T.K.; Kortelainen, M.
2005-01-01
Aggregation of environmental pressures into a single environmental damage index is a major challenge of eco-efficiency measurement. This article examines how the data envelopment analysis (DEA) method can be adapted for this purpose. DEA accounts for substitution possibilities between different
Biomass production and water use efficiency of grassland in ...
African Journals Online (AJOL)
Using the results from a long-term grazing trial in the Dry Highland Sourveld of the KwaZulu-Natal province, we prepared a water use efficiency value (the ratio of the increment in annual biomass to total annual evapotranspiration) for this rangeland type. Using seasonal biomass measurements recorded between March ...
Productive Efficiency of Small Scale Sawmilling Industries in Mufindi ...
African Journals Online (AJOL)
A structured questionnaire was used to collect data from 80 small-scale sawmills in Mufindi District. Data were analysed using descriptive as well as quantitative methods. Technical, scale and allocative efficiency score of sawmills were computed using data envelopment analysis programme developed by Coelli. Censored ...
Assessing the Economic Efficiency of Maize Production in Northern ...
African Journals Online (AJOL)
2017-05-01
May 1, 2017 ... successes of the green revolution in Asia brought to the fore agriculture's ... Maize is a very important staple food in Ghana accounting for more than 50% of total .... The cost efficiency function is specified by changing the error from the to ..... A Guide to Frontier Version 4.1: A computer program for Frontier.
Effect Of Credit Constraint On Production Efficiency Of Farm ...
African Journals Online (AJOL)
Credit constraint in agriculture affects not only the purchasing power of producers to procure farm inputs and to cover operating costs in the short run, but also their capacity to make farm-related investments as well as risk behavior in technology choice and adoption. These, in turn, influence technical efficiencies of the ...
Energy Efficiency, Building Productivity and the Commercial Buildings Market
Energy Technology Data Exchange (ETDEWEB)
Jones, D.W.
2002-05-16
The energy-efficiency gap literature suggests that building buyers are often short-sighted in their failure to apply life-cycle costing principles to energy efficient building technologies, with the result that under investment in these advanced technology occurs. This study examines the reasons this behavior may occur, by analyzing the pressures that market forces place on purchasers of buildings. Our basic conclusion is that the fundamental manner in which the buildings sector does business creates pressures to reduce initial capital outlays and to hedge against a variety of risks, including the ability of building owners to capture benefits from energy efficiency. Starting from the position that building buyers' willingness to pay drives choices over building attributes, we examine basic market principles, the structure of the buildings market, including the role of lenders, and policies that promote penetration of energy efficient technologies. We conclude that greater attention to buyers, and to the incentives and constraints they face, would promote a better understanding of building investment choices and contribute to better policies to promote the penetration of these technologies into markets.
Cassava productivity linked to potassium's influence on water use efficiency
Ezui, K.S.; Franke, A.C.; Leffelaar, P.A.; Giller, K.E.
2017-01-01
This paper presents the results of field studies conducted in Togo (Djakakope and Sevekpota) to assess the effect of potassium (K) on cassava yield, water use efficiency (WUE) and transpiration as affected by nitrogen (N) and phosphorus (P) availability under rainfed conditions. It was shown that an
Economic Efficiency of Establishing Domestic Production of Synthetic Liquid Fuel
Directory of Open Access Journals (Sweden)
Kyzym Mykola O.
2017-06-01
Full Text Available The article notes a stable tendency to increasing the oil dependence of Ukraine, which creates a threat to the national economic security, and proves an expediency of establishing domestic production of synthetic liquid fuel. The technical, organizational and economic features of establishing synthetic liquid fuel production in Ukraine are presented. There proved a hypothesis on the expediency of organizing the production of synthetic liquid fuels based on steam-plasma coal gasification technology. The forecast resource cycle of the country until 2020 under conditions of developing this technology is modeled.
An Entropy-Based Adaptive Hybrid Particle Swarm Optimization for Disassembly Line Balancing Problems
Directory of Open Access Journals (Sweden)
Shanli Xiao
2017-11-01
Full Text Available In order to improve the product disassembly efficiency, the disassembly line balancing problem (DLBP is transformed into a problem of searching for the optimum path in the directed and weighted graph by constructing the disassembly hierarchy information graph (DHIG. Then, combining the characteristic of the disassembly sequence, an entropy-based adaptive hybrid particle swarm optimization algorithm (AHPSO is presented. In this algorithm, entropy is introduced to measure the changing tendency of population diversity, and the dimension learning, crossover and mutation operator are used to increase the probability of producing feasible disassembly solutions (FDS. Performance of the proposed methodology is tested on the primary problem instances available in the literature, and the results are compared with other evolutionary algorithms. The results show that the proposed algorithm is efficient to solve the complex DLBP.
DEFF Research Database (Denmark)
Yuri, Shtarkov; Justesen, Jørn
1997-01-01
The concept of entropy for an image on a discrete two dimensional grid is introduced. This concept is used as an information theoretic bound on the coding rate for the image. It is proved that this quantity exists as a limit for arbitrary sets satisfying certain conditions.......The concept of entropy for an image on a discrete two dimensional grid is introduced. This concept is used as an information theoretic bound on the coding rate for the image. It is proved that this quantity exists as a limit for arbitrary sets satisfying certain conditions....
Directory of Open Access Journals (Sweden)
F. TopsÃƒÂ¸e
2001-09-01
Full Text Available Abstract: In its modern formulation, the Maximum Entropy Principle was promoted by E.T. Jaynes, starting in the mid-fifties. The principle dictates that one should look for a distribution, consistent with available information, which maximizes the entropy. However, this principle focuses only on distributions and it appears advantageous to bring information theoretical thinking more prominently into play by also focusing on the "observer" and on coding. This view was brought forward by the second named author in the late seventies and is the view we will follow-up on here. It leads to the consideration of a certain game, the Code Length Game and, via standard game theoretical thinking, to a principle of Game Theoretical Equilibrium. This principle is more basic than the Maximum Entropy Principle in the sense that the search for one type of optimal strategies in the Code Length Game translates directly into the search for distributions with maximum entropy. In the present paper we offer a self-contained and comprehensive treatment of fundamentals of both principles mentioned, based on a study of the Code Length Game. Though new concepts and results are presented, the reading should be instructional and accessible to a rather wide audience, at least if certain mathematical details are left aside at a rst reading. The most frequently studied instance of entropy maximization pertains to the Mean Energy Model which involves a moment constraint related to a given function, here taken to represent "energy". This type of application is very well known from the literature with hundreds of applications pertaining to several different elds and will also here serve as important illustration of the theory. But our approach reaches further, especially regarding the study of continuity properties of the entropy function, and this leads to new results which allow a discussion of models with so-called entropy loss. These results have tempted us to speculate over
International Nuclear Information System (INIS)
Ponman, T.J.
1984-01-01
For some years now two different expressions have been in use for maximum entropy image restoration and there has been some controversy over which one is appropriate for a given problem. Here two further entropies are presented and it is argued that there is no single correct algorithm. The properties of the four different methods are compared using simple 1D simulations with a view to showing how they can be used together to gain as much information as possible about the original object. (orig.)
Entanglement entropy and duality
Energy Technology Data Exchange (ETDEWEB)
Radičević, Ðorđe [Stanford Institute for Theoretical Physics and Department of Physics, Stanford University, Stanford, CA 94305-4060 (United States)
2016-11-22
Using the algebraic approach to entanglement entropy, we study several dual pairs of lattice theories and show how the entropy is completely preserved across each duality. Our main result is that a maximal algebra of observables in a region typically dualizes to a non-maximal algebra in a dual region. In particular, we show how the usual notion of tracing out external degrees of freedom dualizes to a tracing out coupled to an additional summation over superselection sectors. We briefly comment on possible extensions of our results to more intricate dualities, including holographic ones.
SOWING GRASSLANDS – EFFICIENT SOLUTION FOR ZOOTEHNICAL PRODUCTION
Directory of Open Access Journals (Sweden)
VALENTINA OFELIA ROBESCU
2008-05-01
Full Text Available Recruitment is critical for the maintenance of plant populations and community diversity, but sexual regeneration is considered to be infrequent in climatically harsh habitats such as sub alpine grasslands. For this reasons it is very important to improve the grassland. In this paper we study the interaction among milk production, fertilizations and flower composition in sub alpine grasslands. The agrochemical indicators are important because they influence the pasture value and at the final the milk production.
Crop and soil specific N and P efficiency and productivity in Finland
Bäckman, S.; Oude Lansink, A.G.J.M.
2005-01-01
This paper estimates a stochastic production frontier based on experimental data of cereals production in Finland over the period 1977-1994. The estimates of the production frontier are used to analyze nitrogen and phosphorous productivity and efficiency differences between soils and crops. For this
Strategies for improving water use efficiency in livestock feed production in rain-fed systems
Kebebe, E.G.; Oosting, S.J.; Haileslassie, A.; Duncan, A.J.; Boer, de I.J.M.
2015-01-01
Livestock production is a major consumer of fresh water, and the influence of livestock production on global fresh water resources is increasing because of the growing demand for livestock products. Increasing water use efficiency of livestock production, therefore, can contribute to the overall
India's Fertilizer Industry: Productivity and Energy Efficiency
Energy Technology Data Exchange (ETDEWEB)
Schumacher, K.; Sathaye, J.
1999-07-01
Historical estimates of productivity growth in India's fertilizer sector vary from indicating an improvement to a decline in the sector's productivity. The variance may be traced to the time period of study, source of data for analysis, and type of indices and econometric specifications used for reporting productivity growth. Our analysis shows that in the twenty year period, 1973 to 1993, productivity in the fertilizer sector increased by 2.3% per annum. An econometric analysis reveals that technical progress in India's fertilizer sector has been biased towards the use of energy, while it has been capital and labor saving. The increase in productivity took place during the era of total control when a retention price system and distribution control was in effect. With liberalization of the fertilizer sector and reduction of subsidies productivity declined substantially since the early 1990s. Industrial policies and fiscal incentives still play a major role in the Indian fertilizer sect or. As substantial energy savings and carbon reduction potential exists, energy policies can help overcome barriers to the adoption of these measures in giving proper incentives and correcting distorted prices.
Total Factor Productivity and Efficiency Analysis on Islamic Banks in Indonesia
Directory of Open Access Journals (Sweden)
Siti Aisyah
2018-02-01
Full Text Available The aims of this study are to measure productivity and efficiency, to analyze factors which affect the level of efficiency and to analyze correlation between productivity and efficiency of Islamic Banking in Indonesia. The objects of this study are 11 (eleven Islamic Banks (BUS in Indonesia which are analyzed from the second quarter of 2010 to the third quarter of 2015. The result shows only six of the eleven banks that have a good productivity levels, otherwise for efficiency there are only three banks that efficient enough. Furthermore, the relationship between productivity and efficiency levels that are categorized into 4 (four quadrants. In quadrant I, three banks have high productivity and efficiency namely Syariah Mandiri, Panin Syariah and Victoria Syariah; quadrant IV two banks in low level of productivity and efficiency namely Mega Syariah and Bukopin Syariah. While the quadrant II namely BCA Syariah, BRI syariah and Muamalat and quadrant III namely BJB Syariah, BNI Syariah and Maybank Syariah required further research to determine the factors that affect the productivity and efficiency relationships that occur.
2012-06-29
... Efficiency Program for Consumer Products: Energy Conservation Standards for Battery Chargers and External Power Supplies AGENCY: Office of Energy Efficiency and Renewable Energy, Department of Energy. ACTION... Energy Efficiency and Renewable Energy, Building Technologies Program, EE-2J, 1000 Independence Avenue SW...
2013-02-11
... Efficiency Program for Consumer Products: Energy Conservation Standards for Residential Boilers AGENCY: Office of Energy Efficiency and Renewable Energy, Department of Energy. ACTION: Notice of public meeting.... Department of Energy, Office of Energy Efficiency and Renewable Energy, Building Technologies Program, EE-2J...
Lattice-Valued Possibilistic Entropy Measure
Czech Academy of Sciences Publication Activity Database
Kramosil, Ivan
2008-01-01
Roč. 16, č. 6 (2008), s. 829-846 ISSN 0218-4885 R&D Projects: GA AV ČR IAA100300503 Institutional research plan: CEZ:AV0Z10300504 Keywords : complete lattice * lattice-valued possibilistic distribution * entropy measure * product of possibilistic distribution Subject RIV: BA - General Mathematics Impact factor: 1.000, year: 2008
Efficiency of nitrogen fertilizer in rice culture production
International Nuclear Information System (INIS)
Romero, M.R.; Perez, C.; Sosa, J.L.
1990-01-01
Using the isotopic tracer technique with 15 urea, the efficiency of three ways of nitrogen fertilizer splitting in rice was determined. Fractioning at three moments, initial tilloring, active tile ring and primordial change, allowed a better assimilation of nitrogen by the grain and the rest of the plant. The optimum moment for the application of the fertilizer was at primordial change, while the highest took place at seeding
Benner, M.; Geerts, R.F.R.; Linnemann, A.R.; Jongen, W.M.F.; Folstar, P.; Cnossen, H.J.
2003-01-01
New food products often fail, because they are not designed according to consumers' wishes or not produced efficiently. Frequently, the information required for an effective and efficient product development process is not relayed to the appropriate actor in the chain. This article presents a
Benner, M.; Geerts, R.F.R.; Linnemann, A.R.; Jongen, W.M.F.; Folstar, P.; Cnossen, H.J.
2003-01-01
New food products often fail, because they are not designed according to consumers' wishes or not produced efficiently. Frequently, the information required for an effective and efficient product development process is not relayed to the appropriate actor in the chain. This article presents a
Epstein-Barr Virus BKRF4 Gene Product Is Required for Efficient Progeny Production.
Masud, H M Abdullah Al; Watanabe, Takahiro; Yoshida, Masahiro; Sato, Yoshitaka; Goshima, Fumi; Kimura, Hiroshi; Murata, Takayuki
2017-12-01
Epstein-Barr virus (EBV), a member of human gammaherpesvirus, infects mainly B cells. EBV has two alternative life cycles, latent and lytic, and is reactivated occasionally from the latent stage to the lytic cycle. To combat EBV-associated disorders, understanding the molecular mechanisms of the EBV lytic replication cycle is also important. Here, we focused on an EBV lytic gene, BKRF4. Using our anti-BKRF4 antibody, we revealed that the BKRF4 gene product is expressed during the lytic cycle with late kinetics. To characterize the role of BKRF4, we constructed BKRF4-knockout mutants using the bacterial artificial chromosome (BAC) and CRISPR/Cas9 systems. Although disruption of the BKRF4 gene had almost no effect on viral protein expression and DNA synthesis, it significantly decreased progeny virion levels in HEK293 and Akata cells. Furthermore, we show that BKRF4 is involved not only in production of progeny virions but also in increasing the infectivity of the virus particles. Immunoprecipitation assays revealed that BKRF4 interacted with a virion protein, BGLF2. We showed that the C-terminal region of BKRF4 was critical for this interaction and for efficient progeny production. Immunofluorescence analysis revealed that BKRF4 partially colocalized with BGLF2 in the nucleus and perinuclear region. Finally, we showed that BKRF4 is a phosphorylated, possible tegument protein and that the EBV protein kinase BGLF4 may be important for this phosphorylation. Taken together, our data suggest that BKRF4 is involved in the production of infectious virions. IMPORTANCE Although the latent genes of EBV have been studied extensively, the lytic genes are less well characterized. This study focused on one such lytic gene, BKRF4, which is conserved only among gammaherpesviruses (ORF45 of Kaposi's sarcoma-associated herpesvirus or murine herpesvirus 68). After preparing the BKRF4 knockout virus using B95-8 EBV-BAC, we demonstrated that the BKRF4 gene was involved in infectious
Myat, Aung; Thu, Kyaw; Kim, Youngdeuk; Saha, Bidyut Baran; Ng, K. C.
2012-01-01
We present a practical tool that employs entropy generation minimization (EGM) approach for an in-depth performance evaluation of a co-generation plant with a temperature-cascaded concept. Co-generation plant produces useful effect production sequentially, i.e., (i) electricity from the micro-turbines, (ii) low pressure steam at 250 °C or about 8-10 bars, (iii) cooling capacity of 4 refrigeration tones (Rtons) and (iv) dehumidification of outdoor air for air conditioned space. The main objective is to configure the most efficient configuration of producing power and heat. We employed entropy generation minimization (EGM) which reflects to minimize the dissipative losses and maximize the cycle efficiency of the individual thermally activated systems. The minimization of dissipative losses or EGM is performed in two steps namely, (i) adjusting heat source temperatures for the heat-fired cycles and (ii) the use of Genetic Algorithm (GA), to seek out the sensitivity of heat transfer areas, flow rates of working fluids, inlet temperatures of heat sources and coolant, etc., over the anticipated range of operation to achieve maximum efficiency. With EGM equipped with GA, we verified that the local minimization of entropy generation individually at each of the heat-activated processes would lead to the maximum efficiency of the system. © 2012.
Myat, Aung
2012-10-01
We present a practical tool that employs entropy generation minimization (EGM) approach for an in-depth performance evaluation of a co-generation plant with a temperature-cascaded concept. Co-generation plant produces useful effect production sequentially, i.e., (i) electricity from the micro-turbines, (ii) low pressure steam at 250 °C or about 8-10 bars, (iii) cooling capacity of 4 refrigeration tones (Rtons) and (iv) dehumidification of outdoor air for air conditioned space. The main objective is to configure the most efficient configuration of producing power and heat. We employed entropy generation minimization (EGM) which reflects to minimize the dissipative losses and maximize the cycle efficiency of the individual thermally activated systems. The minimization of dissipative losses or EGM is performed in two steps namely, (i) adjusting heat source temperatures for the heat-fired cycles and (ii) the use of Genetic Algorithm (GA), to seek out the sensitivity of heat transfer areas, flow rates of working fluids, inlet temperatures of heat sources and coolant, etc., over the anticipated range of operation to achieve maximum efficiency. With EGM equipped with GA, we verified that the local minimization of entropy generation individually at each of the heat-activated processes would lead to the maximum efficiency of the system. © 2012.
Algebraic entropy for algebraic maps
International Nuclear Information System (INIS)
Hone, A N W; Ragnisco, Orlando; Zullo, Federico
2016-01-01
We propose an extension of the concept of algebraic entropy, as introduced by Bellon and Viallet for rational maps, to algebraic maps (or correspondences) of a certain kind. The corresponding entropy is an index of the complexity of the map. The definition inherits the basic properties from the definition of entropy for rational maps. We give an example with positive entropy, as well as two examples taken from the theory of Bäcklund transformations. (letter)
Revisiting entanglement entropy of lattice gauge theories
Energy Technology Data Exchange (ETDEWEB)
Hung, Ling-Yan [Department of Physics and Center for Field Theory and Particle Physics, Fudan University,220 Handan Lu, Shanghai 200433 (China); Collaborative Innovation Center of Advanced Microstructures, Fudan University,220 Handan Lu, Shanghai 200433 (China); Wan, Yidun [Perimeter Institute for Theoretical Physics,31 Caroline Street, Waterloo, ON N2L 2Y5 (Canada)
2015-04-22
It is realized recently that the entanglement entropy in gauge theories is ambiguous because the Hilbert space cannot be expressed as a simple direct product of Hilbert spaces defined on the two regions; different ways of dividing the Hilbert spaces near the boundary leads to significantly different result, to the extreme that it could annihilate the otherwise finite topological entanglement entropy between two regions altogether. In this article, we first show that the topological entanglement entropy in the Kitaev model http://dx.doi.org/10.1016/S0003-4916(02)00018-0 which is not a true gauge theory, is free of ambiguity. Then, we give a physical interpretation, from the perspectives of what can be measured in an experiment, to the purported ambiguity of true gauge theories, where the topological entanglement arises as redundancy in counting the degrees of freedom along the boundary separating two regions. We generalize these discussions to non-Abelian gauge theories.
International Nuclear Information System (INIS)
Hansen, Frank
2016-01-01
Incremental information, as measured by the quantum entropy, is increasing when two ensembles are united. This result was proved by Lieb and Ruskai, and it is the foundation for the proof of strong subadditivity of quantum entropy. We present a truly elementary proof of this fact in the context of the broader family of matrix entropies introduced by Chen and Tropp.
Energy Technology Data Exchange (ETDEWEB)
Hansen, Frank, E-mail: frank.hansen@m.tohoku.ac.jp [Tohoku University, Institute for Excellence in Higher Education (Japan)
2016-06-15
Incremental information, as measured by the quantum entropy, is increasing when two ensembles are united. This result was proved by Lieb and Ruskai, and it is the foundation for the proof of strong subadditivity of quantum entropy. We present a truly elementary proof of this fact in the context of the broader family of matrix entropies introduced by Chen and Tropp.
Relations Among Some Fuzzy Entropy Formulae
Institute of Scientific and Technical Information of China (English)
卿铭
2004-01-01
Fuzzy entropy has been widely used to analyze and design fuzzy systems, and many fuzzy entropy formulae have been proposed. For further in-deepth analysis of fuzzy entropy, the axioms and some important formulae of fuzzy entropy are introduced. Some equivalence results among these fuzzy entropy formulae are proved, and it is shown that fuzzy entropy is a special distance measurement.
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 9. Entropy à la Boltzmann. Jayanta K Bhattacharjee. General Article Volume 6 Issue 9 September 2001 pp 19-34. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/006/09/0019-0034 ...
Indian Academy of Sciences (India)
Consider the integral. taken over a reversible transformation. We shall call this function the entropy of state A.” 'Thermodynamics' by Enrico Fermi. “Let Γ be the volume of the region of motion of the states, and. This is the basic assumption of ...
Aur, Dorian; Vila-Rodriguez, Fidel
2017-01-01
Complexity measures for time series have been used in many applications to quantify the regularity of one dimensional time series, however many dynamical systems are spatially distributed multidimensional systems. We introduced Dynamic Cross-Entropy (DCE) a novel multidimensional complexity measure that quantifies the degree of regularity of EEG signals in selected frequency bands. Time series generated by discrete logistic equations with varying control parameter r are used to test DCE measures. Sliding window DCE analyses are able to reveal specific period doubling bifurcations that lead to chaos. A similar behavior can be observed in seizures triggered by electroconvulsive therapy (ECT). Sample entropy data show the level of signal complexity in different phases of the ictal ECT. The transition to irregular activity is preceded by the occurrence of cyclic regular behavior. A significant increase of DCE values in successive order from high frequencies in gamma to low frequencies in delta band reveals several phase transitions into less ordered states, possible chaos in the human brain. To our knowledge there are no reliable techniques able to reveal the transition to chaos in case of multidimensional times series. In addition, DCE based on sample entropy appears to be robust to EEG artifacts compared to DCE based on Shannon entropy. The applied technique may offer new approaches to better understand nonlinear brain activity. Copyright Â© 2016 Elsevier B.V. All rights reserved.
Rescaling Temperature and Entropy
Olmsted, John, III
2010-01-01
Temperature and entropy traditionally are expressed in units of kelvin and joule/kelvin. These units obscure some important aspects of the natures of these thermodynamic quantities. Defining a rescaled temperature using the Boltzmann constant, T' = k[subscript B]T, expresses temperature in energy units, thereby emphasizing the close relationship…
Feed intake and production efficiency of beef cows
The objective of this study was to determine the relationships between DMI and growth as heifers and cows and calves weaned, weight of calf weaned, and milk production. Cows born in 1999-2001and sired by industry AI bulls (Angus, Hereford, Simmental, Limousin, Charolais, Gelbvieh, and Red Angus) an...
Determinants of Charcoal Production Efficiency in Ibarapa North ...
African Journals Online (AJOL)
The data obtained were analyzed using descriptive statistics (percentage and frequency and stochastic frontier production function. The study revealed that mean age of producers was 36 years; 96.9% were males and 3.1 were females. Majority of the producers (76.9%) had no formal training on how to produce charcoal, ...
Improving radiation use efficiency in greenhouse production systems
Li, Tao
2015-01-01
SUMMARY
A large increase in agricultural production is needed to feed the increasing world population with their increasing demand per capita. However, growing competition for arable land, water, energy, and the degradation of the environment impose challenges to improve
Resource-Use Efficiency in Rice Production Under Small Scale ...
African Journals Online (AJOL)
This was attested by the high ratios (greater than unity) of MVP/MFC of all the variables. For optimum resource allocation to fertilizer, labour and land about 85.7%, 83.3% and 69% increase in MVP is required respectively. The estimated elasticity of production summed up to 0.815 meaning decreasing return to scale.
Comparison of productive and reproductive efficiency of Afrino ...
African Journals Online (AJOL)
... are the primary factors determining profitability of a specific sheep enterprise. These parameters should thus be considered when changing from one breed or commodity to another. Keywords: Body weight; wool production; slaughter traits; income. South African Journal of Animal Sciences Vol. 35 (2) 2005: pp.98-108 ...
Improved production efficiency in cattle to reduce their carbon ...
African Journals Online (AJOL)
The FAO publication, Livestock's Long Shadow, indicated that livestock is responsible for 18% of the world's greenhouse gas production thereby creating the perception that livestock is a major cause of global warming. Methane (CH4) makes up 16% of total world gas emissions and is the second most important ...
Economic Efficiency of Maize Production in Yola North Local ...
African Journals Online (AJOL)
user
ABSTRACT. The ability of herbaceous legumes to supply nitrogen to subsequent cereal crops could be harnessed to alleviate the difficulties in cereal production due to poor soil fertility and expensive inorganic fertilizers. Field experiments were carried out in Zaria, Nigeria to determine the soil improvement potential of ...
Allocative efficiency, employment and rice production risk: An ...
African Journals Online (AJOL)
Smallholder farmers have developed coping mechanisms in order to minimize the negative impact of rice production risks. A programme to accelerate the provision of education and credit is needed. The education programme should include both formal and non-formal elements. This is important for the improvement of ...
Efficient production of Arthromyces ramosus peroxidase by Aspergillus awamori
Lokman, B.C.; Joosten, V.; Hovenkamp, J.; Gouka, R.J.; Verrips, C.T.; Hondel, C.A.M.J.J. van den
2003-01-01
The heterologous production of Arthromyces ramosus peroxidase (ARP) was analysed in the filamentous fungus Aspergillus awamori under control of the inducible endoxylanase promoter. Secretion of active ARP was achieved up to 800 mg l-1 in shake flask cultures. Western blot analysis showed that an
FORMATION AND DEVELOPMENT OF INSTITUTIONS OF EFFICIENCY PRODUCTION INFRASTRUCTURE
Directory of Open Access Journals (Sweden)
Anzor H. Jankaziev
2015-01-01
Full Text Available The article presents the methodological andmethodical bases of research and development institutes forming efﬁ ciency production infrastructure. Focuses on the organizationalside of the issue as the comparative characteristics. It is proposed allocation of integraland differential approach to assessing the investment attractiveness of the industrial infrastructure of the enterprise. Consideredsectoral, regional, national and internationallevels of development of industrial infrastructure.
Root system-based limits to agricultural productivity and efficiency
DEFF Research Database (Denmark)
Thorup-Kristensen, Kristian; Kirkegaard, John
2016-01-01
of water and nitrogen from deeper soil layers has been proposed to improve productivity and environmental outcomes in both systems. The analysis showed that water and nitrogen availability, especially in deeper layers (>1 m), was significantly affected by the preceding crops and management, and likely...
Energy efficiency improvement target for SIC 34 - fabricated metal products
Energy Technology Data Exchange (ETDEWEB)
Byrer, T. G.; Billhardt, C. F.; Farkas, M. S.
1977-03-15
A March 15, 1977 revision of a February 15, 1977 document on the energy improvement target for the Fabricated Metal Products industry (SIC 34) is presented. A net energy savings in 1980 of 24% as compared with 1972 energy consumption in SIC 34 is considered a realistic goal. (ERA citation 04:045008)
Improving efficiency of polystyrene concrete production with composite binders
Lesovik, R. V.; Ageeva, M. S.; Lesovik, G. A.; Sopin, D. M.; Kazlitina, O. V.; Mitrokhina, A. A.
2018-03-01
According to leading marketing researchers, the construction market in Russia and CIS will continue growing at a rapid rate; this applies not only to a large-scale major construction, but to a construction of single-family houses and small-scale industrial facilities as well. Due to this, there are increased requirements for heat insulation of the building enclosures and a significant demand for efficient walling materials with high thermal performance. All these developments led to higher requirements imposed on the equipment that produces such materials.
Zucker, M. H.
This paper is a critical analysis and reassessment of entropic functioning as it applies to the question of whether the ultimate fate of the universe will be determined in the future to be "open" (expanding forever to expire in a big chill), "closed" (collapsing to a big crunch), or "flat" (balanced forever between the two). The second law of thermodynamics declares that entropy can only increase and that this principle extends, inevitably, to the universe as a whole. This paper takes the position that this extension is an unwarranted projection based neither on experience nonfact - an extrapolation that ignores the powerful effect of a gravitational force acting within a closed system. Since it was originally presented by Clausius, the thermodynamic concept of entropy has been redefined in terms of "order" and "disorder" - order being equated with a low degree of entropy and disorder with a high degree. This revised terminology more subjective than precise, has generated considerable confusion in cosmology in several critical instances. For example - the chaotic fireball of the big bang, interpreted by Stephen Hawking as a state of disorder (high entropy), is infinitely hot and, thermally, represents zero entropy (order). Hawking, apparently focusing on the disorderly "chaotic" aspect, equated it with a high degree of entropy - overlooking the fact that the universe is a thermodynamic system and that the key factor in evaluating the big-bang phenomenon is the infinitely high temperature at the early universe, which can only be equated with zero entropy. This analysis resolves this confusion and reestablishes entropy as a cosmological function integrally linked to temperature. The paper goes on to show that, while all subsystems contained within the universe require external sources of energization to have their temperatures raised, this requirement does not apply to the universe as a whole. The universe is the only system that, by itself can raise its own
Directory of Open Access Journals (Sweden)
Fadzlan Sufian
2014-12-01
Full Text Available The present study employs the state of the art bias-corrected Malmquist Productivity Index method to examine the sources of efficiency and productivity of the foreign and domestic banks operating in the Malaysian banking sector. The preferred methodology enables us to isolate efforts to catch up to the frontier (efficiency change from shifts in the frontier (technological change [TECHCH]. The results indicate that the Malaysian banking sector has exhibited productivity progress mainly attributed to technological progress. The empirical findings suggest that both the domestic and foreign banks have exhibited productivity progress albeit at different quantum attributed mainly to progress in TECHCH.
Financial time series analysis based on effective phase transfer entropy
Yang, Pengbo; Shang, Pengjian; Lin, Aijing
2017-02-01
Transfer entropy is a powerful technique which is able to quantify the impact of one dynamic system on another system. In this paper, we propose the effective phase transfer entropy method based on the transfer entropy method. We use simulated data to test the performance of this method, and the experimental results confirm that the proposed approach is capable of detecting the information transfer between the systems. We also explore the relationship between effective phase transfer entropy and some variables, such as data size, coupling strength and noise. The effective phase transfer entropy is positively correlated with the data size and the coupling strength. Even in the presence of a large amount of noise, it can detect the information transfer between systems, and it is very robust to noise. Moreover, this measure is indeed able to accurately estimate the information flow between systems compared with phase transfer entropy. In order to reflect the application of this method in practice, we apply this method to financial time series and gain new insight into the interactions between systems. It is demonstrated that the effective phase transfer entropy can be used to detect some economic fluctuations in the financial market. To summarize, the effective phase transfer entropy method is a very efficient tool to estimate the information flow between systems.
System Entropy Measurement of Stochastic Partial Differential Systems
Directory of Open Access Journals (Sweden)
Bor-Sen Chen
2016-03-01
Full Text Available System entropy describes the dispersal of a system’s energy and is an indication of the disorder of a physical system. Several system entropy measurement methods have been developed for dynamic systems. However, most real physical systems are always modeled using stochastic partial differential dynamic equations in the spatio-temporal domain. No efficient method currently exists that can calculate the system entropy of stochastic partial differential systems (SPDSs in consideration of the effects of intrinsic random fluctuation and compartment diffusion. In this study, a novel indirect measurement method is proposed for calculating of system entropy of SPDSs using a Hamilton–Jacobi integral inequality (HJII-constrained optimization method. In other words, we solve a nonlinear HJII-constrained optimization problem for measuring the system entropy of nonlinear stochastic partial differential systems (NSPDSs. To simplify the system entropy measurement of NSPDSs, the global linearization technique and finite difference scheme were employed to approximate the nonlinear stochastic spatial state space system. This allows the nonlinear HJII-constrained optimization problem for the system entropy measurement to be transformed to an equivalent linear matrix inequalities (LMIs-constrained optimization problem, which can be easily solved using the MATLAB LMI-toolbox (MATLAB R2014a, version 8.3. Finally, several examples are presented to illustrate the system entropy measurement of SPDSs.
Directory of Open Access Journals (Sweden)
Sisay Diriba Lemessa
2017-09-01
Full Text Available This study analyzes the technical efficiency and production risk of 862 maize farmers in major maize producing regions of Ethiopia. It employs the stochastic frontier approach (SFA to estimate the level of technical efficiencies of stallholder farmers. The stochastic frontier approach (SFA uses flexible risk properties to account for production risk. Thus, maize production variability is assessed from two perspectives, the production risk and the technical efficiency. The study also attempts to determine the socio-economic and farm characteristics that influence technical efficiency of maize production in the study area. The findings of the study showed the existence of both production risk and technical inefficiency in maize production process. Input variables (amounts per hectare such as fertilizer and labor positively influence maize output. The findings also show that farms in the study area exhibit decreasing returns to scale. Fertilizer and ox plough days reduce output risk while labor and improved seed increase output risk. The mean technical efficiency for maize farms is 48 percent. This study concludes that production risk and technical inefficiency prevents the maize farmers from realizing their frontier output. The best factors that improve the efficiency of the maize farmers in the study area include: frequency of extension contact, access to credit and use of intercropping. It was also realized that altitude and terracing in maize farms had influence on farmer efficiency.
Entropy, neutro-entropy and anti-entropy for neutrosophic information
Vasile Patrascu
2017-01-01
This approach presents a multi-valued representation of the neutrosophic information. It highlights the link between the bifuzzy information and neutrosophic one. The constructed deca-valued structure shows the neutrosophic information complexity. This deca-valued structure led to construction of two new concepts for the neutrosophic information: neutro-entropy and anti-entropy. These two concepts are added to the two existing: entropy and non-entropy. Thus, we obtained the following triad: e...
Essays on pig production efficiency and farmers' financial decisions under uncertainty
Labajova, Katarina.
2018-01-01
Recent structural changes in agricultural production towards fewer, but larger, units pose challenges for farmers in decision making about practical production and about managerial practices to increase efficiency, which are vital for farm productivity and profitability. In studies using mathematical programming and econometric models, this thesis evaluated farm-specific characteristics related to the individual technical efficiency (TE) of each input and output factor and of managerial chara...
STRUCTURE OF THE MARKET OF INNOVATIVE PRODUCTS: APPROACH TO ASSESSING THE IMPACT ON EFFICIENCY
Directory of Open Access Journals (Sweden)
Anna Elagina
2015-06-01
Full Text Available The formation of innovation policy innovative economy is impossible without an understanding of the conceptual basis of the efficiency of production of innovative products. In particular, determination of the influence of market structure on the possibility of expanded reproduction of innovative products. The article is devoted to consideration of existing in this field of research and definition of the limits of quantitative assessment of the influence of defects of market structures on efficiency.
Service Co-Production, Customer Efficiency and Market Competition
Mei Xue; Patrick T. Harker
2003-01-01
Customers’ participation in service co-production processes has been increasing with the rapid development of self-service technologies and business models that rely on self-service as the main service delivery channel. However, little is known about how the level of participation of customers in service delivery processes influences the competition among service providers. In this paper, a game-theoretic model is developed to study the competition among service providers when selfservice is ...
Materials and methods for efficient lactic acid production
Zhou, Shengde; Ingram, Lonnie O& #x27; Neal; Shanmugam, Keelnatham T; Yomano, Lorraine; Grabar, Tammy B; Moore, Jonathan C
2013-04-23
The present invention provides derivatives of Escherichia coli constructed for the production of lactic acid. The transformed E. coli of the invention are prepared by deleting the genes that encode competing pathways followed by a growth-based selection for mutants with improved performance. These transformed E. coli are useful for providing an increased supply of lactic acid for use in food and industrial applications.
Entropy, neutro-entropy and anti-entropy for neutrosophic information
Vasile Patrascu
2017-01-01
This article shows a deca-valued representation of neutrosophic information in which are defined the following features: truth, falsity, weak truth, weak falsity, ignorance, contradiction, saturation, neutrality, ambiguity and hesitation. Using these features, there are constructed computing formulas for entropy, neutro-entropy and anti-entropy.
Optimization of photovoltaic energy production through an efficient switching matrix
Directory of Open Access Journals (Sweden)
Pietro Romano
2013-09-01
Full Text Available This work presents a preliminary study on the implementation of a new system for power output maximization of photovoltaic generators under non-homogeneous conditions. The study evaluates the performance of an efficient switching matrix and the relevant automatic reconfiguration control algorithms. The switching matrix is installed between the PV generator and the inverter, allowing a large number of possible module configurations. PV generator, switching matrix and the intelligent controller have been simulated in Simulink. The proposed reconfiguration system improved the energy extracted by the PV generator under non-uniform solar irradiation conditions. Short calculation times of the proposed control algorithms allow its use in real time applications even where a higher number of PV modules is required.
Eco-efficiency Analysis of Furniture Product Using Life Cycle Assessment
Rinawati, Dyah Ika; Sriyanto; Sari, Diana Puspita; Prayodha, Andana Cantya
2018-02-01
Furniture is one of Indonesia's main commodities strategically role in economic growth and employment in Indonesia. In their production process there many wastes resulted, such as such as sawdust, cuttings - pieces of wood, components that do not conform to specifications and the edges of wood from a log. Contrast with requirement of timber for furniture industries, availability of raw material sources decrease because of limited forest areas. Beside that, using electricity and chemical material in furniture production process have impact to environment. This study aim to assess the eco-cost and eco-efficiency ratio of the product so strategic recommendations to improve the eco-efficiency of products can be designed. The results of data processing showed the environmental costs of the furniture production process amount Rp 30.887.84. Eco-efficiency index of furniture products studied was 4,79 with the eco-efficiency ratio of 79,12%. This result means that the measured furniture products already profitable and sustainable, as well as its production process is already fairly efficient. However, improved performance of the production process can still be done to improve the eco-efficiency by minimizing the use of raw materials.
Eco-efficiency Analysis of Furniture Product Using Life Cycle Assessment
Directory of Open Access Journals (Sweden)
Ika Rinawati Dyah
2018-01-01
Full Text Available Furniture is one of Indonesia’s main commodities strategically role in economic growth and employment in Indonesia. In their production process there many wastes resulted, such as such as sawdust, cuttings - pieces of wood, components that do not conform to specifications and the edges of wood from a log. Contrast with requirement of timber for furniture industries, availability of raw material sources decrease because of limited forest areas. Beside that, using electricity and chemical material in furniture production process have impact to environment. This study aim to assess the eco-cost and eco-efficiency ratio of the product so strategic recommendations to improve the eco-efficiency of products can be designed. The results of data processing showed the environmental costs of the furniture production process amount Rp 30.887.84. Eco-efficiency index of furniture products studied was 4,79 with the eco-efficiency ratio of 79,12%. This result means that the measured furniture products already profitable and sustainable, as well as its production process is already fairly efficient. However, improved performance of the production process can still be done to improve the eco-efficiency by minimizing the use of raw materials.
Application of SNODAS and hydrologic models to enhance entropy-based snow monitoring network design
Keum, Jongho; Coulibaly, Paulin; Razavi, Tara; Tapsoba, Dominique; Gobena, Adam; Weber, Frank; Pietroniro, Alain
2018-06-01
Snow has a unique characteristic in the water cycle, that is, snow falls during the entire winter season, but the discharge from snowmelt is typically delayed until the melting period and occurs in a relatively short period. Therefore, reliable observations from an optimal snow monitoring network are necessary for an efficient management of snowmelt water for flood prevention and hydropower generation. The Dual Entropy and Multiobjective Optimization is applied to design snow monitoring networks in La Grande River Basin in Québec and Columbia River Basin in British Columbia. While the networks are optimized to have the maximum amount of information with minimum redundancy based on entropy concepts, this study extends the traditional entropy applications to the hydrometric network design by introducing several improvements. First, several data quantization cases and their effects on the snow network design problems were explored. Second, the applicability the Snow Data Assimilation System (SNODAS) products as synthetic datasets of potential stations was demonstrated in the design of the snow monitoring network of the Columbia River Basin. Third, beyond finding the Pareto-optimal networks from the entropy with multi-objective optimization, the networks obtained for La Grande River Basin were further evaluated by applying three hydrologic models. The calibrated hydrologic models simulated discharges using the updated snow water equivalent data from the Pareto-optimal networks. Then, the model performances for high flows were compared to determine the best optimal network for enhanced spring runoff forecasting.
NEW ECO-EFFICIENT PRODUCTS USED IN LEATHER INDUSTRY
Directory of Open Access Journals (Sweden)
ROSU Dan
2016-05-01
Full Text Available In today's move to "sustainable production" the leather industry, as well as many other industries is recognized as a polluting one. Traditional chemical operations are polluting because of the levels of inorganic chemical waste. Process chemicals which are not consumed within the reactions necessary to convert collagen to leather are currently discharged to waste. These are usually applied during bulk production, such as inorganic agents from beam house and tanning processes, e.g. lime, sulphide, ammonium salts, sulphuric acid and sodium chloride, mineral tanning agents – mainly Cr(III and the less common Al(III, Zr(III, Ti(III, Fe(III salts -, whereas depending on the tanning process and the leather article produced organic chemical waste discharged comprises aldehydic and polyphenolic tanning products, bating enzymes, organic carboxylic acids and excess electrolyte stable synthetic fat liquors. It is rare for chemicals and water to be recovered for re-use from several of these process steps. Moreover, tanners worldwide are required to operate within strict legislative boundaries. Serious drawbacks continuously arise concerning the chrome–tanning process in leather industry and the environmental hazardous consequences of chromium containing effluents. In order to overcome this impediment, a great deal of research has been focused on developing chrome–free tanning methods in the past years, such as titanium tanning. In the present study, Ti–Al tanned bovine leather was characterized by means of SEM microscopy, EDAX elemental analysis, ATR–FTIR spectroscopy, thermogravimetry TGA, and differential scanning calorimetry DSC techniques.
Evaluation of the efficiency and safety in cosmetic products.
Uckaya, Meryem; Uckaya, Fatih; Demir, Nazan; Demir, Yasar
2016-02-29
Chemicals used in cosmetics have to interact with enzymes for beneficial or destroy purpose after they enter in our body. Active sections of enzymes that catalyze reactions have three dimensions and they are active optically. When these limitations of catalytic sections are considered, it may be considered that defining geometric specifications of chemical materials and functional groups they contain may contribute on safety evaluations of cosmetic products. In this study, defining similarities and differences of geometric structures of chemicals that are prohibited to be used in cosmetic products and chemical that are allowed to be used by using group theory and analyze of functional groups that are often encountered in these chemicals are aimed. Molecule formulas related to chemical material of, 276 pieces chemicals that are prohibited to be used in cosmetic products and 65 pieces chemicals that are allowed, are used as the material. Two and three-dimension structures of these formulas are drawn and types and quantity of functional groups they contain are defined. And as a method, freeware (Free Trial) version of "Chem-BioOffice Ultra 13.0 Suite" chemical drawing program to draw two and three-dimension of formulas, "Campus-Licensed" version that are provided for use by our university of "Autodesk 3DS Max" for three-dimension drawings are used. In order to analyze geometric specifications of drawn molecules according to Group Theory and define type and quantity of available functional groups, Excel applications developed by Prof. Dr. Yaşar Demir are used. Copyright © 2016 Elsevier B.V. All rights reserved.
An architecture for efficient reuse in flexible production scenarios
DEFF Research Database (Denmark)
Andersen, Rasmus Hasle; Dalgaard, Lars; Beck, Anders Billesø
2015-01-01
Traditionally, small batch production has not been automated - it has been too resource demanding compared to the expected benefit. However, this is set to change with the new developments in easily trainable robotic co-worker systems, capable of being adapted to new tasks through intuitive user....... We present the DTI Robot CoWorker architecture, which is a generic robotic architecture, which provides a system-independent execution framework for adaptive and interactive robotic applications. Our approach has proven viable as we have successfully automated a complicated integration task (among...
Evanescent magnetic field effects on entropy generation at the onset ...
Indian Academy of Sciences (India)
application of evanescent magnetic field not only suppresses the fluctuation of the ..... the Prigogine's theorem of minimum entropy production is unproven. ... consists in a double spiral configuration and viscous boundary layers in close ...
Entropy, recycling and macroeconomics of water resources
Karakatsanis, Georgios; Mamassis, Nikos; Koutsoyiannis, Demetris
2014-05-01
We propose a macroeconomic model for water quantity and quality supply multipliers derived by water recycling (Karakatsanis et al. 2013). Macroeconomic models that incorporate natural resource conservation have become increasingly important (European Commission et al. 2012). In addition, as an estimated 80% of globally used freshwater is not reused (United Nations 2012), under increasing population trends, water recycling becomes a solution of high priority. Recycling of water resources creates two major conservation effects: (1) conservation of water in reservoirs and aquifers and (2) conservation of ecosystem carrying capacity due to wastewater flux reduction. Statistical distribution properties of the recycling efficiencies -on both water quantity and quality- for each sector are of vital economic importance. Uncertainty and complexity of water reuse in sectors are statistically quantified by entropy. High entropy of recycling efficiency values signifies greater efficiency dispersion; which -in turn- may indicate the need for additional infrastructure for the statistical distribution's both shifting and concentration towards higher efficiencies that lead to higher supply multipliers. Keywords: Entropy, water recycling, water supply multipliers, conservation, recycling efficiencies, macroeconomics References 1. European Commission (EC), Food and Agriculture Organization (FAO), International Monetary Fund (IMF), Organization of Economic Cooperation and Development (OECD), United Nations (UN) and World Bank (2012), System of Environmental and Economic Accounting (SEEA) Central Framework (White cover publication), United Nations Statistics Division 2. Karakatsanis, G., N. Mamassis, D. Koutsoyiannis and A. Efstratiades (2013), Entropy and reliability of water use via a statistical approach of scarcity, 5th EGU Leonardo Conference - Hydrofractals 2013 - STAHY '13, Kos Island, Greece, European Geosciences Union, International Association of Hydrological Sciences
The different paths to entropy
International Nuclear Information System (INIS)
Benguigui, L
2013-01-01
In order to understand how the complex concept of entropy emerged, we propose a trip into the past, reviewing the works of Clausius, Boltzmann, Gibbs and Planck. In particular, since Gibbs's work is not very well known we present a detailed analysis, recalling the three definitions of entropy that Gibbs gives. The introduction of entropy in quantum mechanics gives in a compact form all the classical definitions of entropy. Perhaps one of the most important aspects of entropy is to see it as a thermodynamic potential like the others proposed by Callen. The calculation of fluctuations in thermodynamic quantities is thus naturally related to entropy. We close with some remarks on entropy and irreversibility. (paper)
Efficient approach for bioethanol production from red seaweed Gelidium amansii.
Kim, Ho Myeong; Wi, Seung Gon; Jung, Sera; Song, Younho; Bae, Hyeun-Jong
2015-01-01
Gelidium amansii (GA), a red seaweed species, is a popular source of food and chemicals due to its high galactose and glucose content. In this study, we investigated the potential of bioethanol production from autoclave-treated GA (ATGA). The proposed method involved autoclaving GA for 60min for hydrolysis to glucose. Separate hydrolysis and fermentation processing (SHF) achieved a maximum ethanol concentration of 3.33mg/mL, with a conversion yield of 74.7% after 6h (2% substrate loading, w/v). In contrast, simultaneous saccharification and fermentation (SSF) produced an ethanol concentration of 3.78mg/mL, with an ethanol conversion yield of 84.9% after 12h. We also recorded an ethanol concentration of 25.7mg/mL from SSF processing of 15% (w/v) dry matter from ATGA after 24h. These results indicate that autoclaving can improve the glucose and ethanol conversion yield of GA, and that SSF is superior to SHF for ethanol production. Copyright © 2014 Elsevier Ltd. All rights reserved.
Symbolic transfer entropy-based premature signal analysis
International Nuclear Information System (INIS)
Wang Jun; Yu Zheng-Feng
2012-01-01
In this paper, we use symbolic transfer entropy to study the coupling strength between premature signals. Numerical experiments show that three types of signal couplings are in the same direction. Among them, normal signal coupling is the strongest, followed by that of premature ventricular contractions, and that of atrial premature beats is the weakest. The T test shows that the entropies of the three signals are distinct. Symbolic transfer entropy requires less data, can distinguish the three types of signals and has very good computational efficiency. (interdisciplinary physics and related areas of science and technology)
Efficient production of ultrapure manganese oxides via electrodeposition.
Cheney, Marcos A; Joo, Sang Woo; Banerjee, Arghya; Min, Bong-Ki
2012-08-01
A new process for the production of electrolytic amorphous nanomanganese oxides (EAMD) with uniform size and morphology is described. EAMD are produced for the first time by cathodic deposition from a basic aqueous solution of potassium permanganate at a constant temperature of 16°C. The synthesized materials are characterized by XRD, SEM, TEM, and HRTEM. The materials produced at 5.0 V at constant temperature are amorphous with homogeneous size and morphology with an average particle size around 20 nm, which appears to be much lesser than the previously reported anodic EAMD. A potentiostatic electrodeposition with much lesser deposition rate (with respect to previously reported anodic depositions) is considered to be the reason behind the very low and homogenous particle size distribution due to the lesser agglomeration of our as-synthesized nanoparticles. Copyright © 2012 Elsevier Inc. All rights reserved.