Optimized, Competitive Supercritical-CO2 Cycle GFR for Gen IV Service
International Nuclear Information System (INIS)
M.J. Driscoll; P. Hejzlar; G. Apostolakis
2008-01-01
An overall plant design was developed for a gas-cooled fast reactor employing a direct supercritical Brayton power conversion system. The most important findings were that (1) the concept could be capital-cost competitive, but startup fuel cycle costs are penalized by the low core power density, specified in large part to satisfy the goal of significant post-accident passive natural convection cooling; (2) active decay heat removal is preferable as the first line of defense, with passive performance in a backup role; (3) an innovative tube-in-duct fuel assembly, vented to the primary coolant, appears to be practicable; and (4) use of the S-Co2 GFR to support hydrogen production is a synergistic application, since sufficient energy can be recuperated from the product H2 and 02 to allow the electrolysis cell to run 250 C hotter than the reactor coolant, and the water boilers can be used for reactor decay heat removal. Increasing core power density is identified as the top priority for future work on GFRs of this type
Equilibrium transuranic management scheme for diverse fuel cycle analysis
International Nuclear Information System (INIS)
Haas, Jason; Lee, John C.
2008-01-01
A key issue cited in the U.S. Department of Energy's report to Congress (2003) on the research path for the Advanced Fuel Cycle Initiative (AFCI) is an accurate estimation of life cycle costs for the construction, operation, decontamination and decommissioning of all fuel cycle facilities. In this report we discuss the methodology and validation of a fuel cycle model based on equilibrium operation. We apply our model to a diverse set of advanced reactors and fuel types in order to determine the most effective transmuting system while simultaneously minimizing fuel cycle costs. Our analysis shows that a nearly instant equilibrium modeling of fuel cycle scenarios can accurately approximate the detailed complex dynamic models developed by national laboratories. Our analysis also shows that the cost of transmuting Spent Nuclear Fuel (SNF) from a UO 2 fueled Pressurized Water Reactor (PWR) is minimized by utilizing the thorium cycle in sodium cooled fast reactors and is near the cost for long term repository storage of SNF at Yucca Mountain. (authors)
International Nuclear Information System (INIS)
Baum, R.P.; Prasad, V.
2007-01-01
Full text: Aim: To determine the effect of peptide receptor radionuclide therapy on GFR after 2 cycles of Y-90-DTATATE as compared to Lu-177-DOTA-TATE. Methods: Group A (Y-90), Group B (Lu-177). Group A1: 24 pts (age 60.5±11a), injected with 4.00± 0.72 GBq of Y-90 (1st cycle). Group A2: 16 pts (age 62.2±9.4a, followed up after 7.8 GBq±0.82 GBq of Y-90 (after 2nd cycle). Group B1: 14 pts (age 62.2±10.6a) 4.8± 0.8 GBq Lu-177 (1st cycle). Group B2: 6 patients (age 58.5±12a) after 9.57±1.5 GBq of Lu-177 (after 2nd cycle). GFR was determined using 110- 185 MBq of Tc-99m DTPA before and 3-4 months after therapy. Absolute/normalized values for GFR pre/post PRRT were compared (paired T-test).The effect of total amount of radioactivity administered, pre-existing diabetes, hypertension and age on renal function post 2 cycles of PRRT were also evaluated. Results: In group A1 normalized GFR dropped by 2% (absol. GFR fall: 2 ml/min) as compared to 16% in group A2 (absol. GFR fall: 7 ml/min). Baseline normalized/absol. GFR values were 1.02/87.5 ml/min in subgroup A1 and 1.02 / 86.5 ml/min in A2. The fall in both, the absolute and normalized GFR values was not significant after the 1st cycle (p=0.555), but was significant (p= 0.007) after the 2nd PRRT. In group B1 there was a fall of normalized GFR value by 10% vs. 8% in group B2. The fall in absol. GFR value was 7.7 ml/min in group B1 and 9.7 ml/min in group B2. Baseline normalized GFR values was 0.86 and 0.89 in subgroups B1 and B2, respectively. Baseline absol. GFR value was 78.3 ml/min and 81 ml/min in subgroups B1 and B2. The fall in the absol. GFR values was significant after the 1st cycle (p=.009), but was not significant (p=0.486) after the 2nd cycle of PRRT. The fall in normalized GFR value was not significant in both subgroups (p=0.07 after 1st cycle and p=0.49 after 2nd cycle). No correlation between the activity administered and the percentage change in the GFR values in both the groups (Pearson's correlation
Numerical study of optimal equilibrium cycles for pressurized water reactors
International Nuclear Information System (INIS)
Mahlers, Y.P.
2003-01-01
An algorithm based on simulated annealing and successive linear programming is applied to solve equilibrium cycle optimization problems for pressurized water reactors. In these problems, the core reload scheme is represented by discrete variables, while the cycle length as well as uranium enrichment and loading of burnable poison in each feed fuel assembly are treated as continuous variables. The enrichments are considered to be distinct in all feed fuel assemblies. The number of batches and their sizes are not fixed and also determined by the algorithm. An important feature of the algorithm is that all the parameters are determined by the solution of one optimization problem including both discrete and continuous variables. To search for the best reload scheme, simulated annealing is used. The optimum cycle length as well as uranium enrichment and loading of burnable poison in each feed fuel assembly are determined for each reload pattern examined using successive linear programming. Numerical results of equilibrium cycle optimization for various values of the effective price of electricity and fuel reprocessing cost are studied
Characteristics of several equilibrium fuel cycles of PWR
International Nuclear Information System (INIS)
Waris, Abdul; Sekimoto, Hiroshi
2001-01-01
This paper evaluated the influence of neutron spectrum on characteristics of several equilibrium fuel cycles of pressurized water reactor (PWR). In this study, five kinds of fuel cycles were investigated. Required uranium enrichment, required natural uranium amount, and toxicity of heavy metals (HMs) in spent fuel were presented for comparison. The results showed that the enrichment and the required amount of natural uranium decrease significantly with increasing number of confined heavy nuclides when uranium is discharged from the reactor. On the other hand, when uranium is totally confined, the enrichment becomes extremely high. The confinement of plutonium and minor actinides (MA) seems effective in reducing radio-toxicity of discharged wastes. By confining all heavy nuclides except uranium those three characteristics could be reduced considerably. For this fuel cycle the toxicity of HMs in spent fuel become nearly equal to or less than that of loaded uranium. (author)
Increased fuel burn-up and fuel cycle equilibrium
International Nuclear Information System (INIS)
Debes, M.
2001-01-01
Improvement of nuclear competitiveness will rely mainly on increased fuel performance, with higher burn-up, and reactors sustained life. Regarding spent fuel management, the EDF current policy relies on UO 2 fuel reprocessing (around 850 MTHM/year at La Hague) and MOX recycling to ensure plutonium flux adequacy (around 100 MTHM/year, with an electricity production equivalent to 30 TWh). This policy enables to reuse fuel material, while maintaining global kWh economy with existing facilities. It goes along with current perspective to increase fuel burn-up up to 57 GWday/t mean in 2010. The following presentation describes the consequences of higher fuel burn-up on fuel cycle and waste management and implementation of a long term and global equilibrium for decades in spent fuel management resulting from this strategy. (author)
Equilíbrio e ciclos Equilibrium and cycles
Directory of Open Access Journals (Sweden)
Matheus Albergaria de Magalhães
2005-12-01
Full Text Available A agenda de pesquisa relacionada a modelos de ciclos reais de negócios (Real-Business-Cycle models - RBC apresentou um crescimento exponencial desde seu surgimento, no início da década de 1980. Os modelos iniciais do gênero partiam de economias simplificadas, sem imperfeições, buscando explicar as oscilações de curto prazo da economia (ciclos a partir de um arcabouço de equilíbrio geral walrasiano. Atualmente, modelos RBC são amplamente usados na macroeconomia, com uma ênfase especial na análise dos aspectos quantitativos das flutuações econômicas. O objetivo do presente artigo é, portanto, realizar uma resenha da primeira fase da agenda RBC. Apesar dos diversos resultados controversos obtidos, é provável que a principal contribuição dessa agenda seja de cunho metodológico, uma vez que a pesquisa daí advinda afetou profundamente as formas de modelagem macroeconômica vigentes hoje em dia.The research agenda related to Real-Business-Cycle models (RBC has shown a remarkable growth since its beginning, in the eighties. The first models of this kind departed from simple economies without imperfections and tried to explain short-run macroeconomic movements (cycles from Walrasian general-equilibrium settings. Nowadays, RBC models are widely used in Macroeconomics, with a special emphasis on the quantitative aspects of economic fluctuations. The main goal of this paper is to provide a survey of the first stage of the RBC research agenda, since there is not a systematic survey of this literature available in Portuguese. Although there are several controversial results related to RBC models, its main contribution seems to be methodological, since these models had a profound impact on current macroeconomic modeling.
Energy Technology Data Exchange (ETDEWEB)
Geemert, R. van E-mail: rene.vangeemert@psi.ch; Hoogenboom, J.E. E-mail: j.e.hoogenboom@iri.tudelft.nl
2001-09-01
As nuclear fuel economy is basically a multi-cycle issue, a fair way of evaluating reload patterns is to consider their performance in the case of an equilibrium cycle. The equilibrium cycle associated with a reload pattern is defined as the limit fuel cycle that eventually emerges after multiple successive periodic refueling, each time implementing the same reload scheme. Since the equilibrium cycle is the solution of a reload operation invariance equation, it can in principle be found with sufficient accuracy only by applying an iterative procedure, simulating the emergence of the limit cycle. For a design purpose such as the optimization of reload patterns, in which many different equilibrium cycle perturbations (resulting from many different limited changes in the reload operator) must be evaluated, this requires far too much computational effort. However, for very fast calculation of these many different equilibrium cycle perturbations it is also possible to set up a generalized variational approach. This approach results in an iterative scheme that yields the exact perturbation in the equilibrium cycle solution as well, in an accelerated way. Furthermore, both the solution of the adjoint equations occurring in the perturbation theory formalism and the implementation of the optimization algorithm have been parallellized and executed on a massively parallel machine. The combination of parallellism and generalized perturbation theory offers the opportunity to perform very exhaustive, fast and accurate sampling of the solution space for the equilibrium cycle reload pattern optimization problem.
International Nuclear Information System (INIS)
Hu, Y.; Liu, Z.; Shi, X.; Wang, B.
2006-01-01
A brief introduction of characteristic statistic algorithm (CSA) is given in the paper, which is a new global optimization algorithm to solve the problem of PWR in-core fuel management optimization. CSA is modified by the adoption of back propagation neural network and fast local adjustment. Then the modified CSA is applied to PWR Equilibrium Cycle Reloading Optimization, and the corresponding optimization code of CSA-DYW is developed. CSA-DYW is used to optimize the equilibrium cycle of 18 month reloading of Daya bay nuclear plant Unit 1 reactor. The results show that CSA-DYW has high efficiency and good global performance on PWR Equilibrium Cycle Reloading Optimization. (authors)
International Nuclear Information System (INIS)
Aragones, J.M.; Martinez-Val, J.M.; Corella, M.R.
1977-01-01
Fuel management requires that mass, energy, and reactivity balance be satisfied in each reload cycle. Procedures for selection of alternatives, core-state models, and fuel cost calculations have been developed for both equilibrium and transition cycles. Effective cycle lengths and fuel cycle variables--namely, reload batch size, schedule of incore residence for the fuel, feed enrichments, energy sharing cycle by cycle, and discharge burnup and isotopics--are the variables being considered for fuel management planning with a given energy generation plan, fuel design, recycling strategy, and financial assumptions
Burnup effect on nuclear fuel cycle cost using an equilibrium model
International Nuclear Information System (INIS)
Youn, S. R.; Kim, S. K.; Ko, W. I.
2014-01-01
The degree of fuel burnup is an important technical parameter to the nuclear fuel cycle, being sensitive and progressive to reduce the total volume of process flow materials and eventually cut the nuclear fuel cycle costs. This paper performed the sensitivity analysis of the total nuclear fuel cycle costs to changes in the technical parameter by varying the degree of burnups in each of the three nuclear fuel cycles using an equilibrium model. Important as burnup does, burnup effect was used among the cost drivers of fuel cycle, as the technical parameter. The fuel cycle options analyzed in this paper are three different fuel cycle options as follows: PWR-Once Through Cycle(PWR-OT), PWR-MOX Recycle, Pyro-SFR Recycle. These fuel cycles are most likely to be adopted in the foreseeable future. As a result of the sensitivity analysis on burnup effect of each three different nuclear fuel cycle costs, PWR-MOX turned out to be the most influenced by burnup changes. Next to PWR-MOX cycle, in the order of Pyro-SFR and PWR-OT cycle turned out to be influenced by the degree of burnup. In conclusion, the degree of burnup in the three nuclear fuel cycles can act as the controlling driver of nuclear fuel cycle costs due to a reduction in the volume of spent fuel leading better availability and capacity factors. However, the equilibrium model used in this paper has a limit that time-dependent material flow and cost calculation is impossible. Hence, comparative analysis of the results calculated by dynamic model hereafter and the calculation results using an equilibrium model should be proceed. Moving forward to the foreseeable future with increasing burnups, further studies regarding alternative material of high corrosion resistance fuel cladding for the overall
A new estimation method for nuclide number densities in equilibrium cycle
International Nuclear Information System (INIS)
Seino, Takeshi; Sekimoto, Hiroshi; Ando, Yoshihira.
1997-01-01
A new method is proposed for estimating nuclide number densities of LWR equilibrium cycle by multi-recycling calculation. Conventionally, it is necessary to spend a large computation time for attaining the ultimate equilibrium state. Hence, the cycle in nearly constant fuel composition has been considered as an equilibrium state which can be achieved by a few of recycling calculations on a simulated cycle operation under a specific fuel core design. The present method uses steady state fuel nuclide number densities as the initial guess for multi-recycling burnup calculation obtained by a continuously fuel supplied core model. The number densities are modified to be the initial number densities for nuclides of a batch supplied fuel. It was found that the calculated number densities could attain to more precise equilibrium state than that of a conventional multi-recycling calculation with a small number of recyclings. In particular, the present method could give the ultimate equilibrium number densities of the nuclides with the higher mass number than 245 Cm and 244 Pu which were not able to attain to the ultimate equilibrium state within a reasonable number of iterations using a conventional method. (author)
Gas-Cooled Fast Reactor (GFR) Decay Heat Removal Concepts
International Nuclear Information System (INIS)
K. D. Weaver; L-Y. Cheng; H. Ludewig; J. Jo
2005-01-01
Current research and development on the Gas-Cooled Fast Reactor (GFR) has focused on the design of safety systems that will remove the decay heat during accident conditions, ion irradiations of candidate ceramic materials, joining studies of oxide dispersion strengthened alloys; and within the Advanced Fuel Cycle Initiative (AFCI) the fabrication of carbide fuels and ceramic fuel matrix materials, development of non-halide precursor low density and high density ceramic coatings, and neutron irradiation of candidate ceramic fuel matrix and metallic materials. The vast majority of this work has focused on the reference design for the GFR: a helium-cooled, direct power conversion system that will operate with an outlet temperature of 850 C at 7 MPa. In addition to the work being performed in the United States, seven international partners under the Generation IV International Forum (GIF) have identified their interest in participating in research related to the development of the GFR. These are Euratom (European Commission), France, Japan, South Africa, South Korea, Switzerland, and the United Kingdom. Of these, Euratom (including the United Kingdom), France, and Japan have active research activities with respect to the GFR. The research includes GFR design and safety, and fuels/in-core materials/fuel cycle projects. This report is a compilation of work performed on decay heat removal systems for a 2400 MWt GFR during this fiscal year (FY05)
International Nuclear Information System (INIS)
Park, Tongkyu; Yang, Won Sik; Kim, Sang-Ji
2017-01-01
Highlights: • An enhanced search algorithm for charged fuel enrichment was developed for equilibrium cycle analysis with REBUS-3. • The new search algorithm is not sensitive to the user-specified initial guesses. • The new algorithm reduces the computational time by a factor of 2–3. - Abstract: This paper presents an enhanced search algorithm for the charged fuel enrichment in equilibrium cycle analysis of REBUS-3. The current enrichment search algorithm of REBUS-3 takes a large number of iterations to yield a converged solution or even terminates without a converged solution when the user-specified initial guesses are far from the solution. To resolve the convergence problem and to reduce the computational time, an enhanced search algorithm was developed. The enhanced algorithm is based on the idea of minimizing the number of enrichment estimates by allowing drastic enrichment changes and by optimizing the current search algorithm of REBUS-3. Three equilibrium cycle problems with recycling, without recycling and of high discharge burnup were defined and a series of sensitivity analyses were performed with a wide range of user-specified initial guesses. Test results showed that the enhanced search algorithm is able to produce a converged solution regardless of the initial guesses. In addition, it was able to reduce the number of flux calculations by a factor of 2.9, 1.8, and 1.7 for equilibrium cycle problems with recycling, without recycling, and of high discharge burnup, respectively, compared to the current search algorithm.
Optimization of in-core fuel management and control rod strategy in equilibrium fuel cycle
International Nuclear Information System (INIS)
Sekimizu, Koichi
1975-01-01
An in-core fuel management problem is formulated for the equilibrium fuel cycle in an N-region nuclear reactor model. The formulation shows that the infinite multiplication factor k infinity requisite for newly charged fuel can be separated into two terms - one corresponding to the average k infinity at the end of the cycle and the other representing the direct contribution of the shuffling scheme and control rod programming. This formulation is applied to a three-region cylindrical reactor to obtain simultaneous optimization of shuffling and control rod programming. It is demonstrated that this formulation aids greatly in gaining a better understanding of the effects of changes in the shuffling scheme and control rod programming on equilibrium fuel cycle performance. (auth.)
Preliminary study on characteristics of equilibrium thorium fuel cycle of BWR
International Nuclear Information System (INIS)
Waris, A.; Kurniadi, R.; Su'ud, Z.; Permana, S.
2007-01-01
One of the main objectives behind the transuranium recycling ideas is not merely to utilize natural resource that is uranium much more efficiently, but to reduce the environmental impact of the radio-toxicity of the nuclear spent fuel. Beside uranium resource, there is thorium which has three times abundance compared to that of uranium which can be utilized as nuclear fuel. On top of that thorium is believed to have less radio-toxicity of spent fuel since its produce smaller amount of higher actinides compared to that of uranium. However, the studies on the thorium utilization in nuclear reactor in particular in light water reactors (LWR) are not performed intensively yet. Therefore, the aim of the present study is to evaluate the characteristics of thorium fuel cycle in LWR, especially boiling water reactor (BWR). To conduct the comprehensive investigations we have employed the equilibrium burnup model (1-3). The equilibrium burnup model is an alternative powerful method since its can handle all possible generated nuclides in any nuclear system. Moreover, this method is a simple time independent method. Hence the equilibrium burnup method could be very useful for evaluating and forecasting the characteristics of any nuclear fuel cycle, even the strange one, e.g. all nuclides are confined in the reactor1). We have employed 1368 nuclides in the equilibrium burnup calculation where 129 of them are heavy metals (HMs). This burnup code then is coupled with SRAC cell calculation code by using PIJ module to compose an equilibrium-cell burnup code. For cell calculation, 26 HMs, 66 fission products (FPs) and one pseudo FP have been utilized. The JENDL 3.2 library has been used in this study. References: 1. A. Waris and H. Sekimoto, 'Characteristics of several equilibrium fuel cycles of PWR', J. Nucl. Sci. Technol., 38, p.517-526, 2001 2. A. Waris, H. Sekimoto, and G. Kastchiev, Influence of Moderator-to-Fuel Volume Ratio on Pu and MA Recycling in Equilibrium Fuel Cycles of
Investigation of Equilibrium Core by recycling MA and LLFP in fast reactor cycle (I)
International Nuclear Information System (INIS)
Mizutani, Akihiko; Shono, Akira; Ishikawa, Makoto
1999-05-01
Feasibility study on a self-consistent fuel cycle system is performed in the nuclear fuel recycle system with fast reactors. In this system, the self-generated MAs (Minor Actinides) and LLFPs (Long Lived Fission Products) are confined and incinerated in the fast reactor. Analyses of the nuclear properties for an 'Equilibrium Core', in which the self-generated MAs and LLFPs are confined, are investigated. A conventional sodium cooled oxide fuel fast reactor is selected as the core specifications for the 'Equilibrium Core'. This 600 MWe fast reactor does not have a radial blanket. In this study, the nuclear characteristics of the 'Equilibrium Core' are compared with those of a 'Standard Core' and '5 w/oMA Core'. The 'Standard Core' does not confine MAs and LLFPs in the core, and a 5 w/o-MA Rom LWR is loaded in the '5 w/oMA Core'. Through this comparison between 'Equilibrium Core' and the others, the specific characters of the 'Equilibrium Core' are investigated. In order to realize the 'Equilibrium Core' in the viewpoint of nuclear properties, whether the conventional design concept of fast reactors must be changed or not is also evaluated. The analyses for the nitride and metallic fuel cores are also performed because of their different nuclear characteristics compared with the oxide fuel core. Assuming the separation of REs (Rare Earth elements) from MAs and the isotope separation of LLFPs, most of the nuclear properties for the 'Equilibrium Core' are not beyond those for the '5 w/oMA Core'. It is, therefore, possible to bring the 'Equilibrium Core' into existence without any drastic modification for the design concept of the typical oxide fuel fast reactors. Although the 15.1[w/o] LLFPs are loading in the core of the oxide fuel 'Equilibrium Core', a breeding ratio is more than 1.0 and the difference in a amount of plutonium between a charging and discharging is only 0.04 [ton/year]. Without any drastic change for the design concept of the conventional oxide fuel
Glomerular filtration rate (GFR) and estimation of the GFR (eGFR) in ...
African Journals Online (AJOL)
in 2001 and has since worked at several laboratories within the Central region of the NHLS. Correspondence to: Jocelyn .... that female lean body mass was approx 15% lower).6 The ... estimation of GFR as part of management of patients with ...
Directory of Open Access Journals (Sweden)
Mohammad Masum Alam
2016-07-01
Full Text Available Background: Glomerular filtration rate is an effective tool for diagnosis and staging of chronic kidney disease. The effect ofrenal insufficiency by different method of this tool among patients with CKD is controversial.Objective: The objective of this study was to evaluate the performance of eGFR in staging of CKD compared to gamma camera based GFR.Methods: This cross sectional analytical study was conducted in the Department of Biochemistry Bangabandhu Sheikh Mujib Medical University (BSMMU with the collaboration with National Institute of Nuclear Medicine and Allied Sciences, BSMMU during the period of January 2011 to December 2012. Gama camera based GFR was estimated from DTP A reno gram and eGFR was estimated by three prediction equations. Comparison was done by Bland Altman agreement test to see the agreement on the measurement of GFR between three equation based eGFR method and gama camera based GFR method. Staging comparison was done by Kappa analysis to see the agreement between the stages identified by those different methods.Results: Bland-Altman agreement analysis between GFR measured by gamma camera, CG equation ,CG equation corrected by BSA and MDRD equation shows statistically significant. CKD stages determined by CG GFR, CG GFR corrected by BSA , MDRD GFR and gamma camera based GFR was compared by Kappa statistical analysis .The kappa value was 0.66, 0.77 and 0.79 respectively.Conclusions: This study findings suggest that GFR estimation by MDRD equation in CKD patients shows good agreement with gamma camera based GFR and for staging of CKD patients, eGFR by MDRD formula may be used as very effective tool in Bangladeshi population.
Gas-Cooled Fast Reactor (GFR) FY05 Annual Report
Energy Technology Data Exchange (ETDEWEB)
K. D. Weaver; T. Marshall; T. Totemeier; J. Gan; E.E. Feldman; E.A Hoffman; R.F. Kulak; I.U. Therios; C. P. Tzanos; T.Y.C. Wei; L-Y. Cheng; H. Ludewig; J. Jo; R. Nanstad; W. Corwin; V. G. Krishnardula; W. F. Gale; J. W. Fergus; P. Sabharwall; T. Allen
2005-09-01
The gas-cooled fast reactor (GFR) was chosen as one of the Generation IV nuclear reactor systems to be developed based on its excellent potential for sustainability through reduction of the volume and radio toxicity of both its own fuel and other spent nuclear fuel, and for extending/utilizing uranium resources orders of magnitude beyond what the current open fuel cycle can realize. In addition, energy conversion at high thermal efficiency is possible with the current designs being considered, thus increasing the economic benefit of the GFR. However, research and development challenges include the ability to use passive decay heat removal systems during accident conditions, survivability of fuels and in-core materials under extreme temperatures and radiation, and economical and efficient fuel cycle processes. Nevertheless, the GFR was chosen as one of only six Generation IV systems to be pursued based on its ability to meet the Generation IV goals in sustainability, economics, safety and reliability, proliferation resistance and physical protection. Current research and development on the Gas-Cooled Fast Reactor (GFR) has focused on the design of safety systems that will remove the decay heat during accident conditions, ion irradiations of candidate ceramic materials, joining studies of oxide dispersion strengthened alloys; and within the Advanced Fuel Cycle Initiative (AFCI) the fabrication of carbide fuels and ceramic fuel matrix materials, development of non-halide precursor low density and high density ceramic coatings, and neutron irradiation of candidate ceramic fuel matrix and metallic materials. The vast majority of this work has focused on the reference design for the GFR: a helium-cooled, direct power conversion system that will operate with on outlet temperature of 850 C at 7 MPa. In addition to the work being performed in the United States, seven international partners under the Generation IV International Forum (GIF) have identified their interest in
Plutonium and minor actinides recycle in equilibrium fuel cycles of pressurized water reactor
Energy Technology Data Exchange (ETDEWEB)
Waris, A.; Sekimoto, H. [Research Lab. for Nuclear Reactors, Tokyo Institute of Technology, Tokyo (Japan)
2001-07-01
A study on plutonium and minor actinides (MA) recycle in equilibrium fuel cycles of pressurized water reactors (PWR) has been performed. The calculation results showed that the enrichment and the required amount of natural uranium decrease significantly with increasing number of confined plutonium and MA when uranium is discharged from the reactor. However, when uranium is totally confined, the enrichment becomes extremely high. The recycle of plutonium and MA together with discharging uranium can reduce the radio-toxicity of discharged heavy metal (HM) waste to become less than that of loaded uranium. (author)
International Nuclear Information System (INIS)
Gray S. Chang
2005-01-01
The currently being developed advanced High Temperature gas-cooled Reactors (HTR) is able to achieve a simplification of safety through reliance on innovative features and passive systems. One of the innovative features in these HTRs is reliance on ceramic-coated fuel particles to retain the fission products even under extreme accident conditions. Traditionally, the effect of the random fuel kernel distribution in the fuel pebble/block is addressed through the use of the Dancoff correction factor in the resonance treatment. However, the Dancoff correction factor is a function of burnup and fuel kernel packing factor, which requires that the Dancoff correction factor be updated during Equilibrium Fuel Cycle (EqFC) analysis. An advanced KbK-sph model and whole pebble super lattice model (PSLM), which can address and update the burnup dependent Dancoff effect during the EqFC analysis. The pebble homogeneous lattice model (HLM) is verified by the burnup characteristics with the double-heterogeneous KbK-sph lattice model results. This study summarizes and compares the KbK-sph lattice model and HLM burnup analyzed results. Finally, we discuss the Monte-Carlo coupling with a fuel depletion and buildup code--ORIGEN-2 as a fuel burnup analysis tool and its PSLM calculated results for the HTR EqFC burnup analysis
GFR demonstrator ALLEGRO design status
International Nuclear Information System (INIS)
Poette, C.; Malo, J.Y.; Brun-Magaud, V.; Morin, F.; Dor, I.; Mathieu, B.; Duhamel, H.; Stainsby, R.; Mikityuk, K.
2009-01-01
The ALLEGRO project has the ambitious goal of building and operating the first Gas Cooled Fast Reactor (GFR). It will be a low power experimental reactor with the main objective to validate on a pilot scale the specific GFR technologies (fuel element and sub-assembly, safety systems). It is a loop type, non electricity generating reactor. Its power is about 80 MW. The approach for the core includes first MOX cores loaded with some ceramic mixed carbide or nitride sub-assemblies with SiC/SiCf cladding and wrappers. When such unit test will be considered convincing enough, the diagrid and circuits are designed to accept full high temperature ceramic cores. The core neutrons can also be used to irradiate structural materials with fast neutron spectrum and in a large temperature range. The core can also include innovative irradiation fuel devices (samples or full bundles) for other reactor systems. Finally, the primary circuit can be connected to a test loop to validate the reactor coupled operation of a high temperature process or component. The paper deals with the current ALLEGRO design studies on a mid term roadmap aiming at ending the viability phase in 2012 in order to make a decision in 2013 for further detailed design and construction. Since 2005, the ALLEGRO design studies are shared in the GCFR 6th Framework Program which gathers 10 partners from 6 European countries. The paper will give an overview of recent progresses in various areas such as: - Last 3D core physics analysis of the MOX cores and their irradiation performances in terms of fast flux, dose/burnup, irradiation locations. - The design of experimental advanced ceramic GFR fuel sub-assemblies included in several locations of the MOX core. - Fuel handling principles and solutions. - System design and global reactor architecture which is largely influenced by the Decay Heat Removal strategy (DHR) for depressurized accidents. - An overview of the system transient analysis performed by the partners
Basic study on characteristics of some important equilibrium fuel cycles of PWR
International Nuclear Information System (INIS)
Waris, A.; Sekimoto, H.
2001-01-01
Equilibrium fuel cycle characteristics of a light water reactor (LWR) with enriched uranium supply were evaluated. In this study, five kinds of fuel cycles of 3000 MWt pressurized water reactor (PWR) were investigated, and a method to determine the uranium enrichment in order to achieve their criticality was presented. The results show that the enrichment decreases considerably with increasing number of confined heavy nuclides when U is discharged from the reactor. The required natural uranium was also evaluated for two different enrichment processes. The amount of required natural uranium also decreases as well. On the other hand, when U is totally confined, the enrichment becomes unacceptably high. Furthermore, Pu and minor actinides (MA) confining seem effective to incinerate the discharged radio-toxic wastes
International Nuclear Information System (INIS)
Mizutani, Akihiko; Shono, Akira; Ishikawa, Makoto
2000-02-01
A feasibility study has been performed on a self-consistent fuel cycle system in the nuclear fuel recycle system with fast reactors. In this system, the self-generated MAs (Minor Actinides) and LLFPs (Long-Lived Fission Products) are confined and incinerated in the fast reactor, which is called the 'Equilibrium Core' concept. However, as the isotope separations for selected LLFPs have been assumed in this cycle system, it seems that this assumption is far from realistic one from the viewpoint of economy with respect to the fuel cycle system. In this study, the possibility for realization of the 'Equilibrium Core' concept is evaluated for three fuel types such as oxide, nitride and metallic fuels, provided that the isotopic separation of LLFPs is changed to the element one. This study provides, that is to say, how many LLFP elements can be confined in the 'Equilibrium Core' with element separation. This report examines the nuclear properties of the Equilibrium Core' for various combinations of LLFP incineration schemes from the viewpoints of the risk of geological disposal and the limit in confinable quantity of LLFPs. From the viewpoint of the risk of geological disposal estimated by the retardation factor, it is possible to confine with element separation for Tc, I and Se even in the oxide fueled core. From the standpoint of the limit of confinable amounts of LLFPs, on the other hand, Tc, I, Se, Sn and Cs can be confined with element separate only in case that the nitride fuel is chosen. (author)
The tropical water and energy cycles in a cumulus ensemble model. Part 1: Equilibrium climate
Sui, C. H.; Lau, K. M.; Tao, W. K.; Simpson, J.
1994-01-01
A cumulus ensemble model is used to study the tropical water and energy cycles and their role in the climate system. The model includes cloud dynamics, radiative processes, and microphysics that incorporate all important production and conversion processes among water vapor and five species of hydrometeors. Radiative transfer in clouds is parameterized based on cloud contents and size distributions of each bulk hydrometeor. Several model integrations have been carried out under a variety of imposed boundary and large-scale conditions. In Part 1 of this paper, the primary focus is on the water and heat budgets of the control experiment, which is designed to simulate the convective - radiative equilibrium response of the model to an imposed vertical velocity and a fixed sea surface temperature at 28 C. The simulated atmosphere is conditionally unstable below the freezing level and close to neutral above the freezing level. The equilibrium water budget shows that the total moisture source, M(sub s), which is contributed by surface evaporation (0.24 M(sub s)) and the large-scale advection (0.76 M(sub s)), all converts to mean surface precipitation bar-P(sub s). Most of M(sub s) is transported verticaly in convective regions where much of the condensate is generated and falls to surface (0.68 bar-P(sub s)). The remaining condensate detrains at a rate of 0.48 bar-P(sub s) and constitutes 65% of the source for stratiform clouds above the melting level. The upper-level stratiform cloud dissipates into clear environment at a rate of 0.14 bar-P(sub s), which is a significant moisture source comparable to the detrained water vapor (0.15 bar-P(sub s)) to the upper troposphere from convective clouds. In the lower troposphere, stratiform clouds evaporate at a rate of 0.41 bar-P(sub s), which is a more dominant moisture source than surface evaporation (0.22 bar-P(sub s)). The precipitation falling to the surface in the stratiform region is about 0.32 bar-P(sub s). The associated
Gas-Cooled Fast Reactor (GFR) FY04 Annual Report
Energy Technology Data Exchange (ETDEWEB)
K. D. Weaver; T. C. Totemeier; D. E. Clark; E. E. Feldman; E. A. Hoffman; R. B. Vilim; T. Y. C. Wei; J. Gan; M. K. Meyer; W. F. Gale; M. J. Driscoll; M. Golay; G. Apostolakis; K. Czerwinski
2004-09-01
The gas-cooled fast reactor (GFR) was chosen as one of the Generation IV nuclear reactor systems to be developed based on its excellent potential for sustainability through reduction of the volume and radio toxicity of both its own fuel and other spent nuclear fuel, and for extending/utilizing uranium resources orders of magnitude beyond what the current open fuel cycle can realize. In addition, energy conversion at high thermal efficiency is possible with the current designs being considered, thus increasing the economic benefit of the GFR. However, research and development challenges include the ability to use passive decay heat removal systems during accident conditions, survivability of fuels and in-core materials under extreme temperatures and radiation, and economical and efficient fuel cycle processes. Nevertheless, the GFR was chosen as one of only six Generation IV systems to be pursued based on its ability to meet the Generation IV goals in sustainability, economics, safety and reliability, proliferation resistance and physical protection.
Energy Technology Data Exchange (ETDEWEB)
Dworak, A
1973-03-15
The aim of this survey is to calculate an equilibrium Thorium fuel cycle for a 1000 MW HHT-core in off-load refuelling with hexagonal monolith moulded fuel blocks. It was tried to achieve an axial power distribution similar to the advanced pebble-bed reactors (OTTO) by introducing three axial core zones with different heavy metal content and initial enrichment.
Application of load follow operation to equilibrium cycle of OPR1000
Energy Technology Data Exchange (ETDEWEB)
Lee, Kyeongju; Choe, Jiwon; Lee, Deokjung [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)
2012-10-15
All nuclear power plants in Korea are operated at a base load, that is 100% rated power, and do not rely largely on power tracking control except for startup, shutdown, and some minor problem occurrences. However, if the electricity from nuclear power plants exceeds 50% of total electricity generation according to national energy plan, load follow operation is necessary to efficiently use the electrical energy. But it is very difficult to control the axial power distribution and reactor core reactivity at the same time as needed because of variations in nuclear system parameters. In 1990s, an advanced reactor control algorithm, Mode-K, was developed which uses regulation banks, boron control, and a heavy-worth bank (H-bank). The regulation banks and boron control are used for core reactivity control and the H-bank is used for the control of axial power shape. In this study, reactor core simulations with HELIOS/MASTER code system using Mode-K strategy are applied to the daily load follow operation in equilibrium cycle of OPR1000.
Void reactivity decomposition for the Sodium-cooled Fast Reactor in equilibrium fuel cycle
Energy Technology Data Exchange (ETDEWEB)
Sun Kaichao, E-mail: kaichao.sun@psi.ch [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland); Krepel, Jiri; Mikityuk, Konstantin; Pelloni, Sandro [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Chawla, Rakesh [Paul Scherrer Institut (PSI), 5232 Villigen PSI (Switzerland); Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland)
2011-07-15
Highlights: > We analyze the void reactivity effect for three ESFR core fuel cycle states. > The void reactivity effect is decomposed by neutron balance method. > Novelly, the normalization to the integral flux in the active core is applied. > The decomposition is compared with the perturbation theory based results. > The mechanism and the differences of the void reactivity effect are explained. - Abstract: The Sodium-cooled Fast Reactor (SFR) is one of the most promising Generation IV systems with many advantages, but has one dominating neutronic drawback - a positive sodium void reactivity. The aim of this study is to develop and apply a methodology, which should help better understand the causes and consequences of the sodium void effect. It focuses not only on the beginning-of-life (BOL) state of the core, but also on the beginning of open and closed equilibrium (BOC and BEC, respectively) fuel cycle conditions. The deeper understanding of the principal phenomena involved may subsequently lead to appropriate optimization studies. Various voiding scenarios, corresponding to different spatial zones, e.g. node or assembly, have been analyzed, and the most conservative case - the voiding of both inner and outer fuel zones - has been selected as the reference scenario. On the basis of the neutron balance method, the corresponding SFR void reactivity has been decomposed reaction-, isotope-, and energy-group-wise. Complementary results, based on generalized perturbation theory and sensitivity analysis, are also presented. The numerical analysis for both neutron balance and perturbation theory methods has been carried out using appropriate modules of the ERANOS code system. A strong correlation between the flux worth, i.e. the product of flux and adjoint flux, and the void reactivity importance distributions has been found for the node- and assembly-wise voiding scenarios. The neutron balance based decomposition has shown that the void effect is caused mainly by the
Void reactivity decomposition for the Sodium-cooled Fast Reactor in equilibrium fuel cycle
International Nuclear Information System (INIS)
Sun Kaichao; Krepel, Jiri; Mikityuk, Konstantin; Pelloni, Sandro; Chawla, Rakesh
2011-01-01
Highlights: → We analyze the void reactivity effect for three ESFR core fuel cycle states. → The void reactivity effect is decomposed by neutron balance method. → Novelly, the normalization to the integral flux in the active core is applied. → The decomposition is compared with the perturbation theory based results. → The mechanism and the differences of the void reactivity effect are explained. - Abstract: The Sodium-cooled Fast Reactor (SFR) is one of the most promising Generation IV systems with many advantages, but has one dominating neutronic drawback - a positive sodium void reactivity. The aim of this study is to develop and apply a methodology, which should help better understand the causes and consequences of the sodium void effect. It focuses not only on the beginning-of-life (BOL) state of the core, but also on the beginning of open and closed equilibrium (BOC and BEC, respectively) fuel cycle conditions. The deeper understanding of the principal phenomena involved may subsequently lead to appropriate optimization studies. Various voiding scenarios, corresponding to different spatial zones, e.g. node or assembly, have been analyzed, and the most conservative case - the voiding of both inner and outer fuel zones - has been selected as the reference scenario. On the basis of the neutron balance method, the corresponding SFR void reactivity has been decomposed reaction-, isotope-, and energy-group-wise. Complementary results, based on generalized perturbation theory and sensitivity analysis, are also presented. The numerical analysis for both neutron balance and perturbation theory methods has been carried out using appropriate modules of the ERANOS code system. A strong correlation between the flux worth, i.e. the product of flux and adjoint flux, and the void reactivity importance distributions has been found for the node- and assembly-wise voiding scenarios. The neutron balance based decomposition has shown that the void effect is caused mainly
Interim Status Report on the Design of the Gas-Cooled Fast Reactor (GFR)
International Nuclear Information System (INIS)
Weaver, K. D.
2005-01-01
Current research and development on the Gas-Cooled Fast Reactor (GFR) has focused on the design of safety systems that will remove the decay heat during accident conditions, ion irradiations of candidate ceramic materials, joining studies of oxide dispersion strengthened alloys; and within the Advanced Fuel Cycle Initiative (AFCI) the fabrication of carbide fuels and ceramic fuel matrix materials, development of non-halide precursor low density and high density ceramic coatings, and neutron irradiation of candidate ceramic fuel matrix and metallic materials. The vast majority of this work has focused on the reference design for the GFR: a helium-cooled, direct power conversion system that will operate with on outlet temperature of 850 C at 7 MPa. In addition to the work being performed in the United States, seven international partners under the Generation IV International Forum (GIF) have identified their interest in participating in research related to the development of the GFR. These are Euratom (European Commission), France, Japan, South Africa, South Korea, Switzerland, and the United Kingdom. Of these, Euratom (including the United Kingdom), France, and Japan have active research activities with respect to the GFR. The research includes GFR design and safety, and fuels/in-core materials/fuel cycle projects. This report outlines the current design status of the GFR, and includes work done in the areas mentioned above
International Nuclear Information System (INIS)
Jong, A.J. de.
1992-12-01
We suggest a method to overcome this problem of optimization by varying reloading patterns by characterizing each particular reloading pattern by a set of intermediate parameters that are numbers. Plots of the objective function versus the intermediate parameters can be made. When the intermediate parameters represent the reloading patterns in a unique way, the optimum of the objective function can be found by interpolation within such plots and we can find the optimal reloading pattern in terms of intermediate parameters. These have to be transformed backwards to find an optimal reloading pattern. The intermediate parameters are closely related to the time averaged neutron flux shape in the core during an equilibrium cycle. This flux shape is characterized by a set of ratios of the space averaged fluxes in the fuel zones and the space averaged flux in the zone with the fresh fuel elements. An advantage of this choice of intermediate parameters is that it permits analytical calculation of equilibrium cycle fuel densities in the fuel zones for any applied reloading patten characterized by a set of equilibrium cycle average flux ratios and thus, provides analytical calculations of fuel management objective functions. The method is checked for the burnup of one fissile nuclide in a reactor core with the geometry of the PWR at Borssele. For simplicity, neither the conversion of fuel, nor the buildup of fission products were taken into account in this study. Since these phenomena can also be described by the equilibrium cycle average flux ratios, it is likely that this method can be extended to a more realistic method for global in core fuel management optimization. (orig./GL)
International Nuclear Information System (INIS)
Kim, S. K.; Ko, W. I.; You, S. R.; Gao, R. X.
2015-01-01
This paper examines the difference in the value of the nuclear fuel cycle cost calculated by the deterministic and probabilistic methods on the basis of an equilibrium model. Calculating using the deterministic method, the direct disposal cost and Pyro-SFR (sodium-cooled fast reactor) nuclear fuel cycle cost, including the reactor cost, were found to be 66.41 mills/kWh and 77.82 mills/kWh, respectively (1 mill = one thousand of a dollar, i.e., 10-3 $). This is because the cost of SFR is considerably expensive. Calculating again using the probabilistic method, however, the direct disposal cost and Pyro-SFR nuclear fuel cycle cost, excluding the reactor cost, were found be 7.47 mills/kWh and 6.40 mills/kWh, respectively, on the basis of the most likely value. This is because the nuclear fuel cycle cost is significantly affected by the standard deviation and the mean of the unit cost that includes uncertainty. Thus, it is judged that not only the deterministic method, but also the probabilistic method, would also be necessary to evaluate the nuclear fuel cycle cost. By analyzing the sensitivity of the unit cost in each phase of the nuclear fuel cycle, it was found that the uranium unit price is the most influential factor in determining nuclear fuel cycle costs.
Nuclear Fuel Cycle Analysis by Integrated AHP and TOPSIS Method Using an Equilibrium Model
International Nuclear Information System (INIS)
Yoon, S. R.; Choi, S. Y.; Koc, W. I.
2015-01-01
Determining whether to break away from domestic conflict surrounding nuclear power and step forward for public consensus can be identified by transparent policy making considering public acceptability. In this context, deriving the best suitable nuclear fuel cycle for Korea is the key task in current situation. Assessing nuclear fuel cycle is a multicriteria decision making problem dealing with multiple interconnected issues on efficiently using natural uranium resources, securing an environment friendliness to deal with waste, obtaining the public acceptance, ensuring peaceful uses of nuclear energy, maintaining economic competitiveness compared to other electricity sources, and assessing technical feasibility of advanced nuclear energy systems. This paper performed the integrated AHP and TOPSIS analysis on three nuclear fuel cycle options against 5 different criteria including U utilization, waste management, material attractiveness, economics, and technical feasibility. The fuel cycle options analyzed in this paper are three different fuel cycle options as follows: PWR-Once through cycle(PWR-OT), PWR-MOX cycle, Pyro- SFR cycle. These fuel cycles are most likely to be adopted in the foreseeable future. Analytic Hierarchy Process (AHP) and TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution). The analyzed nuclear fuel cycle options include the once-through cycle, the PWR-MOX recycle, and the Pyro-SFR recycle
Nuclear Fuel Cycle Analysis by Integrated AHP and TOPSIS Method Using an Equilibrium Model
Energy Technology Data Exchange (ETDEWEB)
Yoon, S. R. [University of Science and Technology, Daejeon (Korea, Republic of); Choi, S. Y. [UNIST, Ulju (Korea, Republic of); Koc, W. I. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2015-05-15
Determining whether to break away from domestic conflict surrounding nuclear power and step forward for public consensus can be identified by transparent policy making considering public acceptability. In this context, deriving the best suitable nuclear fuel cycle for Korea is the key task in current situation. Assessing nuclear fuel cycle is a multicriteria decision making problem dealing with multiple interconnected issues on efficiently using natural uranium resources, securing an environment friendliness to deal with waste, obtaining the public acceptance, ensuring peaceful uses of nuclear energy, maintaining economic competitiveness compared to other electricity sources, and assessing technical feasibility of advanced nuclear energy systems. This paper performed the integrated AHP and TOPSIS analysis on three nuclear fuel cycle options against 5 different criteria including U utilization, waste management, material attractiveness, economics, and technical feasibility. The fuel cycle options analyzed in this paper are three different fuel cycle options as follows: PWR-Once through cycle(PWR-OT), PWR-MOX cycle, Pyro- SFR cycle. These fuel cycles are most likely to be adopted in the foreseeable future. Analytic Hierarchy Process (AHP) and TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution). The analyzed nuclear fuel cycle options include the once-through cycle, the PWR-MOX recycle, and the Pyro-SFR recycle.
International Nuclear Information System (INIS)
Fu Hongliang; Li Jinsong; Li Jianing; Wu Jingchuan; Yang Shurong; Gu Zhenhui; Zou Renjian; Shi Haihong
2003-01-01
Objective: To assess glomerular filtration function in patients with type 2 diabetes by glomerular filtration rate (GFR) and split GFR, namely left GFR (LGFR) and right GFR (RGFR). Methods: Fifty-one patients with type 2 diabetes were classified by urine albumin analysis into three groups, normalalbuminuria group (NA), microalbuminuria group(MA) and macroalbuminuria group (MAA) . Twelve patients without diabetes were included into control group. 99 Tc m -DTPA renography was performed on all these cases. GFR and split GFR were calculated by Gates formula. Results: 1) GFR, LGFR and RGFR of NA group were lower than that of the control group. 2) GFR, LGFR and RGFR were significantly correlated with the urine albumin level (r=-0.457, -0.412, -0.424, respectively, P all < 0.01). 3) In all 51 cases, there were 5 cases whose GFR were normal while split GFR were abnormal. Conclusions: 1) GFR and split GFR measurement can detect the incipient damage of glomerular function more sensitively than urine albumin analysis and show the degree of the damage correctly. 2) Split GFR measurement can improve the evaluation of the glomerular function in type 2 diabetes patients
Neutronics/Thermo-fluid Coupled Analysis of PMR-200 Equilibrium Cycle by CAPP/GAMMA+ Code System
Energy Technology Data Exchange (ETDEWEB)
Lee, Hyun Chul; Tak, Nam-il [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2015-10-15
The equilibrium core was obtained by performing CAPP stand-alone multi-cycle depletion calculation with critical rod position search. In this work, a code system for coupled neutronics and thermo-fluids simulation was developed using CAPP and GAMMA+ codes. A server program, INTCA, controls the two codes for coupled calculations and performs the mapping between the variables of the two codes based on the nodalization of the two codes. In order to extend the knowledge about the coupled behavior of a prismatic VHTR, the CAPP/GAMMA+ code system was applied to steady state performance analysis of PMR-200. The coupled calculation was carried out for the equilibrium core of PMR-200 from BOC to EOC. The peak fuel temperature was predicted to be 1372 .deg. C near MOC. However, the cycle-average fuel temperature was calculated as 1230 .deg. C, which is slightly below the design target of 1250 .deg. C. In addition, significant impact of the bypass flow on the central reflector temperature was found. Without bypass flow, the temperature of the active core region was slightly decreased while the temperature of the central and side reflector region was increased much. The both changes in the temperature increase the multiplication factor and the total change of the multiplication factor was more than 300 pcm. On the other hand, the effect of the bypass flow on the power density profile was not significant.
International Nuclear Information System (INIS)
Gougar, Hans D.; Reitsma, Frederik; Joubert, Wessel
2009-01-01
Recirculating pebble-bed reactors are distinguished from all other reactor types by the downward movement through and reinsertion of fuel into the core during operation. Core simulators must account for this movement and mixing in order to capture the physics of the equilibrium cycle core. VSOP and PEBBED are two codes used to perform such simulations, but they do so using different methods. In this study, a simplified pebble-bed core with a specified flux profile and cross sections is used as the model for conducting analyses of two types of burnup schemes. The differences between the codes are described and related to the differences observed in the nuclide densities in pebbles discharged from the core. Differences in the methods for computing fission product buildup and average number densities lead to significant differences in the computed core power and eigenvalue. These test models provide a key component of an overall equilibrium cycle benchmark involving neutron transport, cross section generation, and fuel circulation.
Determination of equilibrium fuel composition for fast reactor in closed fuel cycle
Directory of Open Access Journals (Sweden)
Ternovykha Mikhail
2017-01-01
Full Text Available Technique of evaluation of multiplying and reactivity characteristics of fast reactor operating in the mode of multiple refueling is presented. We describe the calculation model of the vertical section of the reactor. Calculation validations of the possibility of correct application of methods and models are given. Results on the isotopic composition, mass feed, and changes in the reactivity of the reactor in closed fuel cycle are obtained. Recommendations for choosing perspective fuel compositions for further research are proposed.
Energy Technology Data Exchange (ETDEWEB)
Bae, Seong Jun; Lee, Won Woong; Oh, Bongseong; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)
2016-10-15
The features of the S-CO{sub 2} Brayton cycle come from a small compressing work by designing the compressor inlet close the critical point of CO{sub 2}. This means the system condition can be operating under two-phase or sub-critical phase during transient situations such as changes of cooling system performance, load variations, etc. Since there is no operating MW scale S-CO{sub 2} Brayton cycle system in the world yet, using an analytical code is the only way to predict the system behavior and develop operating strategies of the S-CO{sub 2} Brayton cycles. Therefore, the development of a credible system code is an important part for the practical S-CO{sub 2} system research. The current status of the developed system analysis code for S-CO{sub 2} Brayton cycle transient analyses in KAIST and verification results are presented in this paper. To avoid errors related with convergences of the code during the phase changing flow calculation in GAMMA+ code, the authors have developed a system analysis code using Homogeneous Equilibrium Model (HEM) for the S-CO{sub 2} Brayton cycle transient analysis. The backbone of the in-house code is the GAMMA+1.0 code, but treating the quality of fluid by tracking system enthalpy gradient every time step. Thus, the code adopts pressure and enthalpy as the independent scalar variables to track the system enthalpy for updating the quality of the system every time step. The heat conduction solving method, heat transfer correlation and frictional losses on the pipe are referred from the GAMMA+ code.
Long-period Intensity Pulsations in Coronal Loops Explained by Thermal Non-equilibrium Cycles
Energy Technology Data Exchange (ETDEWEB)
Froment, C.; Auchère, F.; Bocchialini, K.; Buchlin, E.; Solomon, J. [Institut d’Astrophysique Spatiale, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Bât. 121, F-91405 Orsay cedex (France); Aulanier, G. [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, F-92195 Meudon (France); Mikić, Z., E-mail: clara.froment@astro.uio.no [Predictive Science, Inc., San Diego, CA 92121 (United States)
2017-02-01
In solar coronal loops, thermal non-equilibrium (TNE) is a phenomenon that can occur when the heating is both highly stratified and quasi-constant. Unambiguous observational identification of TNE would thus permit us to strongly constrain heating scenarios. While TNE is currently the standard interpretation of coronal rain, the long-term periodic evolution predicted by simulations has never been observed. However, the detection of long-period intensity pulsations (periods of several hours) has been recently reported with the Solar and Heliospheric Observatory /EIT, and this phenomenon appears to be very common in loops. Moreover, the three intensity-pulsation events that we recently studied with the Solar Dynamics Observatory /Atmospheric Imaging Assembly (AIA) show strong evidence for TNE in warm loops. In this paper, a realistic loop geometry from linear force-free field (LFFF) extrapolations is used as input to 1D hydrodynamic simulations. Our simulations show that, for the present loop geometry, the heating has to be asymmetrical to produce TNE. We analyze in detail one particular simulation that reproduces the average thermal behavior of one of the pulsating loop bundle observed with AIA. We compare the properties of this simulation with those deduced from the observations. The magnetic topology of the LFFF extrapolations points to the presence of sites of preferred reconnection at one footpoint, supporting the presence of asymmetric heating. In addition, we can reproduce the temporal large-scale intensity properties of the pulsating loops. This simulation further strengthens the interpretation of the observed pulsations as signatures of TNE. This consequently provides important information on the heating localization and timescale for these loops.
Decay profiles of β and γ for a radionuclide inventory in equilibrium cycle of a BWR type reactor
International Nuclear Information System (INIS)
Salaices, M.; Sandoval, S.; Ovando, R.
2007-01-01
Presently work the β and γ radiation decay profiles for a radionuclides inventory in equilibrium cycle of a BWR type reactor is presented. The profiles are presented in terms of decay in the activity of the total inventory as well as of the chemical groups that conform the inventory. In the obtaining of the radionuclides inventory in equilibrium cycle the ORIGEN2 code, version 1 was used, which simulates fuel burnup cycles and it calculates the evolution of the isotopic composition as a result of the burnt one, irradiation and decay of the nuclear fuel. It can be observed starting from the results that the decrease in the activity for the initial inventory and the different chemical groups that conform it is approximately proportional to the base 10 logarithm of the time for the first 24 hours of having concluded the burnt one. It can also be observed that the chemical groups that contribute in more proportion to the total activity of the inventory are the lanthanides-actinides and the transition metals, with 39% and 28%, respectively. The groups of alkaline earth metals, halogens, metalloids, noble gases and alkaline metals, contribute with percentages that go from the 8 to 5%. The groups that less they contribute to the total activity of the inventory they are the non metals and semi-metals with smaller proportions that 1%. The chemical groups that more contribute to the energy of β and γ radiation its are the transition metals and the lanthanides-actinides with a change in the order of importance at the end of the 24 hours period. The case of the halogens is of relevance for the case of the γ radiation energy due that occupying the very near third site to the dimensions of the two previous groups. Additionally, the decay in the activity for the total inventory and the groups that conform it can be simulated by means of order 6 polynomials or smaller than describe its behavior appropriately. The results presented in this work, coupled to a distribution model
Prevalence of estimated GFR reporting among US clinical laboratories.
Accetta, Nancy A; Gladstone, Elisa H; DiSogra, Charles; Wright, Elizabeth C; Briggs, Michael; Narva, Andrew S
2008-10-01
Routine laboratory reporting of estimated glomerular filtration rate (eGFR) may help clinicians detect kidney disease. The current national prevalence of eGFR reporting in clinical laboratories is unknown; thus, the extent of the situation of laboratories not routinely reporting eGFR with serum creatinine results is not quantified. Observational analysis. National Kidney Disease Education Program survey of clinical laboratories conducted in 2006 to 2007 by mail, web, and telephone follow-up. A national random sample, 6,350 clinical laboratories, drawn from the Federal Clinical Laboratory Improvement Amendments database and stratified by 6 major laboratory types/groupings. Laboratory reports serum creatinine results. Reporting eGFR values with serum creatinine results. Percentage of laboratories reporting eGFR along with reporting serum creatinine values, reporting protocol, eGFR formula used, and style of reporting cutoff values. Of laboratories reporting serum creatinine values, 38.4% report eGFR (physician offices, 25.8%; hospitals, 43.6%; independents, 38.9%; community clinics, 47.2%; health fair/insurance/public health, 45.5%; and others, 43.2%). Physician office laboratories have a reporting prevalence lower than other laboratory types (P laboratories reporting eGFR, 66.7% do so routinely with all adult serum creatinine determinations; 71.6% use the 4-variable Modification of Diet in Renal Disease Study equation; and 45.3% use the ">60 mL/min/1.73 m(2)" reporting convention. Independent laboratories are least likely to routinely report eGFR (50.6%; P laboratories across all strata are more likely to report eGFR (P laboratories, federal database did not have names of laboratory directors/managers (intended respondents), assumed accuracy of federal database for sample purposes. Routine eGFR reporting with serum creatinine values is not yet universal, and laboratories vary in their reporting practices.
How to use… serum creatinine, cystatin C and GFR.
Pasala, Swetha; Carmody, J Bryan
2017-02-01
Glomerular filtration rate (GFR) is the best overall measure of kidney function. The GFR is relatively low at birth but increases through infancy and early childhood to reach adult levels of approximately 120 mL/min/1.73 m 2 by age 2. While GFR can be measured most accurately by the urinary clearance of an exogenous ideal filtration marker such as inulin, it is more clinically useful to estimate GFR using a single serum measurement of an endogenous biomarker such as creatinine or cystatin C. When in steady state, there is an inverse relationship between creatinine/cystatin C and GFR, allowing GFR to be estimated from either using simple equations. Because of the non-linear relationship between creatinine/cystatin C and GFR, relatively small initial increases in these markers represent significant decreases in GFR. While cystatin C is produced by all nucleated cells, creatinine is a waste product of muscle metabolism and is therefore influenced by diet and muscle mass/body habitus. Decreased GFR is used to diagnose and stage chronic kidney disease (CKD) using the Kidney Disease: Improving Global Outcomes system. A diagnosis of CKD requires GFR creatinine and urine output are used to diagnose acute kidney injury. It is possible to calculate a kinetic GFR when the creatinine is changing rapidly, though more complex calculations are required. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.
International Nuclear Information System (INIS)
Li, Guanchen; Spakovsky, Michael R. von
2016-01-01
Conventional first principle approaches for studying nonequilibrium or far-from-equilibrium processes depend on the mechanics of individual particles or quantum states. They also require many details of the mechanical features of a system to arrive at a macroscopic property. In contrast, thermodynamics provides an approach for determining macroscopic property values without going into these details, because the overall effect of particle dynamics results, for example, at stable equilibrium in an invariant pattern of the “Maxwellian distribution”, which in turn leads to macroscopic properties. However, such an approach is not generally applicable to a nonequilibrium process except in the near-equilibrium realm. To adequately address these drawbacks, steepest-entropy-ascent quantum thermodynamics (SEAQT) provides a first principle, thermodynamic-ensemble approach applicable to the entire nonequilibrium realm. Based on prior developments by the authors, this paper applies the SEAQT framework to modeling the nonquasi-equilibrium cycle, which a system with variable volume undergoes. Using the concept of hypoequilibrium state and nonequilibrium intensive properties, this framework provides a complete description of the nonequilibrium evolution in state of the system. Results presented here reveal how nonequilibrium effects influence the performance of the cycle. - Highlights: • First-principles nonequilibrium model of thermodynamic cycles. • Study of thermal efficiency losses due to nonequilibrium effects. • Study of systems undergoing nonquasi-equilibrium processes. • Study of the coupling of system relaxation and interaction with a reservoir.
Keddis, Mira T; Amer, Hatem; Voskoboev, Nikolay; Kremers, Walter K; Rule, Andrew D; Lieske, John C
2016-09-07
eGFR equations have been evaluated in kidney transplant recipients with variable performance. We assessed the performance of the Modification of Diet in Renal Disease equation and the Chronic Kidney Disease Epidemiology Collaboration equations on the basis of creatinine, cystatin C, and both (eGFR creatinine-cystatin C) compared with measured GFR by iothalamate clearance and evaluated their non-GFR determinants and associations across 15 cardiovascular risk factors. A cross-sectional cohort of 1139 kidney transplant recipients >1 year after transplant was analyzed. eGFR bias, precision, and accuracy (percentage of estimates within 30% of measured GFR) were assessed. Interaction of each cardiovascular risk factor with eGFR relative to measured GFR was determined. Median measured GFR was 55.0 ml/min per 1.73 m(2). eGFR creatinine overestimated measured GFR by 3.1% (percentage of estimates within 30% of measured GFR of 80.4%), and eGFR Modification of Diet in Renal Disease underestimated measured GFR by 2.2% (percentage of estimates within 30% of measured GFR of 80.4%). eGFR cystatin C underestimated measured GFR by -13.7% (percentage of estimates within 30% of measured GFR of 77.1%), and eGFR creatinine-cystatin C underestimated measured GFR by -8.1% (percentage of estimates within 30% of measured GFR of 86.5%). Lower measured GFR associated with older age, women, obesity, longer time after transplant, lower HDL, lower hemoglobin, lower albumin, higher triglycerides, higher proteinuria, and an elevated cardiac troponin T level but did not associate with diabetes, smoking, cardiovascular events, pretransplant dialysis, or hemoglobin A1c. These risk factor associations differed for five risk factors with eGFR creatinine, six risk factors for eGFR Modification of Diet in Renal Disease, ten risk factors for eGFR cystatin C, and four risk factors for eGFR creatinine-cystatin C. Thus, eGFR creatinine and eGFR creatinine-cystatin C are preferred over eGFR cystatin C in
Baas, M.C.
2011-01-01
The subject of this thesis is twofold: where GFR and mTOR meet. Precise measurement of kidney function is difficult and cumbersome and many, simpler alternatives have been developed to determine GFR. Determination of GFR remains an approximation since the GFR itself is not a static phenomenon. This
Ganji, Hamed Faghanpour; Ganji, Davood Domiri
2017-04-01
In the present paper, brake squeal phenomenon as a noise resource in automobiles was studied. In most cases, the modeling work is carried out assuming that deformations were small; thus, equilibrium point is set zero and linearization is performed at this point. However, the equilibrium point under certain circumstances is not zero; therefore, huge errors in prediction of brake squeal may occur. In this work, large motion domains with respect to linearization importance were subjected to investigation. Nonlinear equations of motion were considered and behavior of system for COF's model was analyzed by studying amplitude and frequency of limited cycle oscillation.
Use of computed tomography assessed kidney length to predict split renal GFR in living kidney donors
Energy Technology Data Exchange (ETDEWEB)
Gaillard, Francois; Fournier, Catherine; Leon, Carine; Legendre, Christophe [Paris Descartes University, AP-HP, Hopital Necker-Enfants Malades, Renal Transplantation Department, Paris (France); Pavlov, Patrik [Linkoeping University, Linkoeping (Sweden); Tissier, Anne-Marie; Correas, Jean-Michel [Paris Descartes University, AP-HP, Hopital Necker-Enfants Malades, Radiology Department, Paris (France); Harache, Benoit; Hignette, Chantal; Weinmann, Pierre [Paris Descartes University, AP-HP, Hopital Europeen Georges Pompidou, Nuclear Medicine Department, Paris (France); Eladari, Dominique [Paris Descartes University, and INSERM, Unit 970, AP-HP, Hopital Europeen Georges Pompidou, Physiology Department, Paris (France); Timsit, Marc-Olivier; Mejean, Arnaud [Paris Descartes University, AP-HP, Hopital Europeen Georges Pompidou, Urology Department, Paris (France); Friedlander, Gerard; Courbebaisse, Marie [Paris Descartes University, and INSERM, Unit 1151, AP-HP, Hopital Europeen Georges Pompidou, Physiology Department, Paris (France); Houillier, Pascal [Paris Descartes University, INSERM, Unit umrs1138, and CNRS Unit erl8228, AP-HP, Hopital Europeen Georges Pompidou, Physiology Department, Paris (France)
2017-02-15
Screening of living kidney donors may require scintigraphy to split glomerular filtration rate (GFR). To determine the usefulness of computed tomography (CT) to split GFR, we compared scintigraphy-split GFR to CT-split GFR. We evaluated CT-split GFR as a screening test to detect scintigraphy-split GFR lower than 40 mL/min/1.73 m{sup 2}/kidney. This was a monocentric retrospective study on 346 potential living donors who had GFR measurement, renal scintigraphy, and CT. We predicted GFR for each kidney by splitting GFR using the following formula: Volume-split GFR for a given kidney = measured GFR*[volume of this kidney/(volume of this kidney + volume of the opposite kidney)]. The same formula was used for length-split GFR. We compared length- and volume-split GFR to scintigraphy-split GFR at donation and with a 4-year follow-up. A better correlation was observed between length-split GFR and scintigraphy-split GFR (r = 0.92) than between volume-split GFR and scintigraphy-split GFR (r = 0.89). A length-split GFR threshold of 45 mL/min/1.73 m{sup 2}/kidney had a sensitivity of 100 % and a specificity of 75 % to detect scintigraphy-split GFR less than 40 mL/min/1.73 m{sup 2}/kidney. Both techniques with their respective thresholds detected living donors with similar eGFR evolution during follow-up. Length-split GFR can be used to detect patients requiring scintigraphy. (orig.)
Use of computed tomography assessed kidney length to predict split renal GFR in living kidney donors
International Nuclear Information System (INIS)
Gaillard, Francois; Fournier, Catherine; Leon, Carine; Legendre, Christophe; Pavlov, Patrik; Tissier, Anne-Marie; Correas, Jean-Michel; Harache, Benoit; Hignette, Chantal; Weinmann, Pierre; Eladari, Dominique; Timsit, Marc-Olivier; Mejean, Arnaud; Friedlander, Gerard; Courbebaisse, Marie; Houillier, Pascal
2017-01-01
Screening of living kidney donors may require scintigraphy to split glomerular filtration rate (GFR). To determine the usefulness of computed tomography (CT) to split GFR, we compared scintigraphy-split GFR to CT-split GFR. We evaluated CT-split GFR as a screening test to detect scintigraphy-split GFR lower than 40 mL/min/1.73 m"2/kidney. This was a monocentric retrospective study on 346 potential living donors who had GFR measurement, renal scintigraphy, and CT. We predicted GFR for each kidney by splitting GFR using the following formula: Volume-split GFR for a given kidney = measured GFR*[volume of this kidney/(volume of this kidney + volume of the opposite kidney)]. The same formula was used for length-split GFR. We compared length- and volume-split GFR to scintigraphy-split GFR at donation and with a 4-year follow-up. A better correlation was observed between length-split GFR and scintigraphy-split GFR (r = 0.92) than between volume-split GFR and scintigraphy-split GFR (r = 0.89). A length-split GFR threshold of 45 mL/min/1.73 m"2/kidney had a sensitivity of 100 % and a specificity of 75 % to detect scintigraphy-split GFR less than 40 mL/min/1.73 m"2/kidney. Both techniques with their respective thresholds detected living donors with similar eGFR evolution during follow-up. Length-split GFR can be used to detect patients requiring scintigraphy. (orig.)
Global Cardiovascular and Renal Outcomes of Reduced GFR.
Thomas, Bernadette; Matsushita, Kunihiro; Abate, Kalkidan Hassen; Al-Aly, Ziyad; Ärnlöv, Johan; Asayama, Kei; Atkins, Robert; Badawi, Alaa; Ballew, Shoshana H; Banerjee, Amitava; Barregård, Lars; Barrett-Connor, Elizabeth; Basu, Sanjay; Bello, Aminu K; Bensenor, Isabela; Bergstrom, Jaclyn; Bikbov, Boris; Blosser, Christopher; Brenner, Hermann; Carrero, Juan-Jesus; Chadban, Steve; Cirillo, Massimo; Cortinovis, Monica; Courville, Karen; Dandona, Lalit; Dandona, Rakhi; Estep, Kara; Fernandes, João; Fischer, Florian; Fox, Caroline; Gansevoort, Ron T; Gona, Philimon N; Gutierrez, Orlando M; Hamidi, Samer; Hanson, Sarah Wulf; Himmelfarb, Jonathan; Jassal, Simerjot K; Jee, Sun Ha; Jha, Vivekanand; Jimenez-Corona, Aida; Jonas, Jost B; Kengne, Andre Pascal; Khader, Yousef; Khang, Young-Ho; Kim, Yun Jin; Klein, Barbara; Klein, Ronald; Kokubo, Yoshihiro; Kolte, Dhaval; Lee, Kristine; Levey, Andrew S; Li, Yongmei; Lotufo, Paulo; El Razek, Hassan Magdy Abd; Mendoza, Walter; Metoki, Hirohito; Mok, Yejin; Muraki, Isao; Muntner, Paul M; Noda, Hiroyuki; Ohkubo, Takayoshi; Ortiz, Alberto; Perico, Norberto; Polkinghorne, Kevan; Al-Radaddi, Rajaa; Remuzzi, Giuseppe; Roth, Gregory; Rothenbacher, Dietrich; Satoh, Michihiro; Saum, Kai-Uwe; Sawhney, Monika; Schöttker, Ben; Shankar, Anoop; Shlipak, Michael; Silva, Diego Augusto Santos; Toyoshima, Hideaki; Ukwaja, Kingsley; Umesawa, Mitsumasa; Vollset, Stein Emil; Warnock, David G; Werdecker, Andrea; Yamagishi, Kazumasa; Yano, Yuichiro; Yonemoto, Naohiro; Zaki, Maysaa El Sayed; Naghavi, Mohsen; Forouzanfar, Mohammad H; Murray, Christopher J L; Coresh, Josef; Vos, Theo
2017-07-01
The burden of premature death and health loss from ESRD is well described. Less is known regarding the burden of cardiovascular disease attributable to reduced GFR. We estimated the prevalence of reduced GFR categories 3, 4, and 5 (not on RRT) for 188 countries at six time points from 1990 to 2013. Relative risks of cardiovascular outcomes by three categories of reduced GFR were calculated by pooled random effects meta-analysis. Results are presented as deaths for outcomes of cardiovascular disease and ESRD and as disability-adjusted life years for outcomes of cardiovascular disease, GFR categories 3, 4, and 5, and ESRD. In 2013, reduced GFR was associated with 4% of deaths worldwide, or 2.2 million deaths (95% uncertainty interval [95% UI], 2.0 to 2.4 million). More than half of these attributable deaths were cardiovascular deaths (1.2 million; 95% UI, 1.1 to 1.4 million), whereas 0.96 million (95% UI, 0.81 to 1.0 million) were ESRD-related deaths. Compared with metabolic risk factors, reduced GFR ranked below high systolic BP, high body mass index, and high fasting plasma glucose, and similarly with high total cholesterol as a risk factor for disability-adjusted life years in both developed and developing world regions. In conclusion, by 2013, cardiovascular deaths attributed to reduced GFR outnumbered ESRD deaths throughout the world. Studies are needed to evaluate the benefit of early detection of CKD and treatment to decrease these deaths. Copyright © 2017 by the American Society of Nephrology.
STUDI KOORDINASI PERALATAN PROTEKSI OCR DAN GFR PADA PENYULANG TIBUBENENG
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Indra Baskara
2015-12-01
Full Text Available Tibubeneng feeder equipped with protective devices over current relay (OCR and ground fault relay (GFR installed in Recloser Dama, Recloser Tandeg and relay feeder Tibubeneng in GI. Based on data from PLN Bali, there are 3 times the interference with the feeder Tibubeneng that cause coordination protection error system. The problem of protection error coordination can be addressed by the study coordinated analysis of protection systems. The analysis was performed by making a curve existing coordination OCR settings and GFR in Tibubeneng feeders and comparing it with the coordination curve setting calculation results. The calculation is performed based on the standards system of protection of sensitive, reliable, fast and remain selective. Based on the analysis of the existing curve setting, an error occurred coordination between the curve and the GFR Recloser Recloser Tandeg Dama indicated by the curves that intersect at several levels of short circuit current value and the value of grading time OCR and GFR was less than 0.4 seconds. Repair work coordination OCR and GFR in Tibubeneng feeder can be done by re-setting in accordance with the results of calculations in order to obtain protection system in accordance with the terms of the security system
Directory of Open Access Journals (Sweden)
F. Álvarez-Velarde
2012-01-01
Full Text Available A fast numerical method for the calculation in a zero-dimensional approach of the equilibrium isotopic composition of an iteratively used transmutation system in an advanced fuel cycle, based on the Banach fixed point theorem, is described in this paper. The method divides the fuel cycle in successive stages: fuel fabrication, storage, irradiation inside the transmutation system, cooling, reprocessing, and incorporation of the external material into the new fresh fuel. The change of the fuel isotopic composition, represented by an isotope vector, is described in a matrix formulation. The resulting matrix equations are solved using direct methods with arbitrary precision arithmetic. The method has been successfully applied to a double-strata fuel cycle with light water reactors and accelerator-driven subcritical systems. After comparison to the results of the EVOLCODE 2.0 burn-up code, the observed differences are about a few percents in the mass estimations of the main actinides.
GFR Prediction From Cystatin C and Creatinine in Children
DEFF Research Database (Denmark)
Andersen, Trine Borup; Jødal, Lars; Boegsted, Martin
2012-01-01
area, and SCr is serum creatinine level. The accuracy and precision of these models were compared with 7 previously published prediction models using random subsampling cross-validation. Local constants and coefficients were calculated for all models. Root mean square error, R2, and percentage...... are still not sufficiently accurate to replace exogenous markers when GFR must be determined with high accuracy....
The MDRD formula does not reflect GFR in ESRD patients
Grootendorst, Diana C.; Michels, Wieneke M.; Richardson, Jermaine D.; Jager, Kitty J.; Boeschoten, Elisabeth W.; Dekker, Friedo W.; Krediet, Raymond T.; Apperloo, A. J.; Bijlsma, J. A.; Boekhout, M.; Boer, W. H.; van der Boog, P. J. M.; Büller, H. R.; van Buren, M.; de Charro, F. Th; Doorenbos, C. J.; van den Dorpel, M. A.; van Es, A.; Fagel, W. J.; Feith, G. W.; de Fijter, C. W. H.; Frenken, L. A. M.; van Geelen, J. A. C. A.; Gerlag, P. G. G.; Gorgels, J. P. M. C.; Grave, W.; Huisman, R. M.; Jie, K.; Koning-Mulder, W. A. H.; Koolen, M. I.; Kremer Hovinga, T. K.; Lavrijssen, A. T. J.; Luik, A. J.; van der Meulen, J.; Parlevliet, K. J.; Raasveld, M. H. M.; van der Sande, F. M.; Schonck, M. J. M.; Schuurmans, M. M. J.; Siegert, C. E. H.; Stegeman, C. A.; Stevens, P.; Thijssen, J. G. P.; Valentijn, R. M.; Vastenburg, G. H.; Verburgh, C. A.; Vincent, H. H.; Vos, P. F.
2011-01-01
The Modification of Diet in Renal Disease (MDRD) equation is widely used for the estimation of glomerular filtration rate (GFR) from plasma creatinine. It has been well validated in patients with various degrees of impaired kidney function, but not in patients with end-stage renal disease (ESRD).
International Nuclear Information System (INIS)
Igos, Elorri; Rugani, Benedetto; Rege, Sameer; Benetto, Enrico; Drouet, Laurent; Zachary, Daniel S.
2015-01-01
Highlights: • The environmental impacts of two energy policy scenarios in Luxembourg are assessed. • Computable General Equilibrium (CGE) and Partial Equilibrium (PE) models are used. • Results from coupling of CGE and PE are integrated in hybrid Life Cycle Assessment. • Impacts due to energy related production and imports are likely to grow over time. • Carbon mitigation policies seem to not substantially decrease the impacts’ trend. - Abstract: Nowadays, many countries adopt an active agenda to mitigate the impact of greenhouse gas emissions by moving towards less polluting energy generation technologies. The environmental costs, directly or indirectly generated to achieve such a challenging objective, remain however largely underexplored. Until now, research has focused either on pure economic approaches such as Computable General Equilibrium (CGE) and partial equilibrium (PE) models, or on (physical) energy supply scenarios. These latter could be used to evaluate the environmental impacts of various energy saving or cleaner technologies via Life Cycle Assessment (LCA) methodology. These modelling efforts have, however, been pursued in isolation, without exploring the possible complementarities and synergies. In this study, we have undertaken a practical combination of these approaches into a common framework: on the one hand, by coupling a CGE with a PE model, and, on the other hand, by linking the outcomes from the coupling with a hybrid input–output−process based life cycle inventory. The methodological framework aimed at assessing the environmental consequences of two energy policy scenarios in Luxembourg between 2010 and 2025. The study highlights the potential of coupling CGE and PE models but also the related methodological difficulties (e.g. small number of available technologies in Luxembourg, intrinsic limitations of the two approaches, etc.). The assessment shows both environmental synergies and trade-offs due to the implementation of
GFR fuel and core pre-conceptual design studies
International Nuclear Information System (INIS)
Chauvin, N.; Ravenet, A.; Lorenzo, D.; Pelletier, M.; Escleine, J.M.; Munoz, I.; Bonnerot, J.M.; Malo, J.Y.; Garnier, J.C.; Bertrand, F.; Bosq, J.C.
2007-01-01
The revision of the GFR core design - plate type - has been undertaken since previous core presented at Global'05. The self-breeding searched for has been achieved with an optimized design ('12/06 E'). The higher core pressure drop was a matter of concern. First of all, the core coolability in natural circulation for pressurized conditions has been studied and preliminary plant transient calculations have been performed. The design and safety criteria are met but no more margin remains. The project is also addressing the feasibility and the design of the fuel S/A. The hexagonal shape together with the principle of closed S/A (wrapper tube) is kept. Ceramic plate type fuel element combines a high enough core power density (minimization of the Pu inventory) and plutonium and minor actinides recycling capabilities. Innovative for many aspects, the fuel element is central to the GFR feasibility. It is supported already by a significant R and D effort also applicable to a pin concept that is considered as the other fuel element of interest. This combination of fuel/core feasibility and performance analysis, safety dispositions and performances analysis will compose the 'GFR preliminary feasibility' which is a project milestone at the end of the year 2007. (authors)
Past Decline Versus Current eGFR and Subsequent Mortality Risk
Naimark, David M. J.; Grams, Morgan E.; Matsushita, Kunihiro; Black, Corri; Drion, Iefke; Fox, Caroline S.; Inker, Lesley A.; Ishani, Areef; Jee, Sun Ha; Kitamura, Akihiko; Lea, Janice P.; Nally, Joseph; Peralta, Carmen Alicia; Rothenbacher, Dietrich; Ryu, Seungho; Tonelli, Marcello; Yatsuya, Hiroshi; Coresh, Josef; Gansevoort, Ron T.; Warnock, David G.; Woodward, Mark; de Jong, Paul E.
A single determination of eGFR associates with subsequent mortality risk. Prior decline in eGFR indicates loss of kidney function, but the relationship to mortality risk is uncertain. We conducted an individual-level meta-analysis of the risk of mortality associated with antecedent eGFR slope,
International Nuclear Information System (INIS)
Shiotani, Hiroki; Ono, Kiyoshi
2009-01-01
The Global Trade and Analysis Project (GTAP) is a widely used computable general equilibrium (CGE) model developed by Purdue University. Although the GTAP-E, an energy environmental version of the GTAP model, is useful for surveying the energy-economy-environment-trade linkage is economic policy analysis, it does not have the decomposed model of the electricity sector and its analyses are comparatively static. In this study, a recursive dynamic CGE model with a detailed electricity technology bundle with nuclear power generation including FR was developed based on the GTAP-E to evaluate the long-term socioeconomic effects of FR deployment. The capital stock changes caused by international investments and some dynamic constraints of the FR deployment and operation (e.g., load following capability and plutonium mass balance) were incorporated in the analyses. The long-term socioeconomic effects resulting from the deployment of economic competitive FR with innovative technologies can be assessed; the cumulative effects of the FR deployment on GDP calculated using this model costed over 40 trillion yen in Japan and 400 trillion yen worldwide, which were several times more than the cost of the effects calculated using the conventional cost-benefit analysis tool, because of ripple effects and energy substitutions among others. (author)
International Nuclear Information System (INIS)
Perusquia, R.; Montes, J.L.; Hernandez, J.L.; Ortiz, J.J.; Hernandez, H.; Castillo, A.
2007-01-01
The Federal Commission of Electricity carries out works at the moment related with the one increase from the power to original 120% of the nominal one in the rectors of water in boil (BWR) of the Laguna Verde Central (CLV). In the National Institute of Nuclear Research (ININ) are carried out studies of the impact on the design of the fuel recharge derived of this increase. As option in the ININ the feasibility of continuing using the same type of fuel assemble that one has come using recently in the CLV, the type GE12 is analyzed. To achieve it was diminished the LPPF of the power cells from 1.43 to 1.24. It was verified, with the recently acquired CMS codes system that the use of fuel assemble GE12 type with cells of low peak of local power and low gadolinia concentration (ININ4) they are suitable for cycles of 18 months at 120% of the original nominal power in the reactors of the CLV. It was decreased the recharge from 148 to 140 when using the ININ4 fuel assemble instead of one conventionally designed. This brings itself appreciable economic savings. However, the above mentioned brought itself an increase of the dispersion in the burnt of definitive fuel discharges. All this when it had already been fulfilled the goals and requirements imposed in the design of the balance cycle. It was necessary to establish a principle with base to the one which it was developed a method that allowed to reduce in efficient form the dispersion of the burnt of discharge and at the same time to already have a low impact in the operational parameters reached. The method was applied in the cycle of balance of 18 months to 120% of the original nominal power using the fuel assemble of low peak of local power being achieved the following results; it was decreased the dispersion of the burnt of definitive discharge from 5.4% to 2.2%, the maximum burnt of discharge was diminished from 50.694 GWD/M to 47.443 GWD/TM, it was increased the minimum burnt of discharge from 41.369 GWD/TM to 42
Risk-informed analysis as a support to the preliminary design of the CEA GFR2400
International Nuclear Information System (INIS)
Bertrand, F.; Bassi, C.; Azria, P.; Bentivoglio, F.; Messie, A.; Balmain, M.
2012-01-01
The integration of safety issues in the early phase of the design of a 4. generation reactor of the concepts is expected. For this purpose, probabilistic insights are increasingly employed in the safety demonstration in combination with the deterministic approach in the frame of a so-called risk informed approach. The present paper deals with the safety assessment of the preliminary design of the GFR2400 developed by CEA and how it has been improved in order to fulfil deterministic criteria as well as to reach a risk level comparable to the generation III reactors. GFR2400 is a 2400 MWth, 3-loops, helium-cooled fast reactor developed at a pre-conceptual design stage whose secondary circuit is filled with a mixture of helium and nitrogen, the ternary circuit being filled with water vaporized in 3 steam generators according to a classical Rankine cycle. The resulting cycle efficiency is very close to 45 %. Considering the results obtained with a preliminary level 1 PSA (L1PSA) model, it emerged that an increased reliability of the DHR (Decay Heat Removal) function in high pressure conditions (not corresponding to a LOCA) was suitable to reduce the overall core damage frequency. On the other hand, some small break LOCA situations were not adequately mitigated according to the line of protection deterministic method. Both issues have been solved by design improvements. In addition, this final L1PSA model, characterized by success criteria based on transient calculations performed with the CATHARE2 code and performed in a perimeter extended to all representative internal initiating events at full operating power, permitted to propose design evolutions that did not increase significantly the CDF. In the same time, those evolutions enabled the DHR system to increase its redundancy level as required in the deterministic approach. Finally, a modified design has been reached implying a more extended covering of various accidental situations by means of a progressive DHR
Deshmukh, Sanket A; Kamath, Ganesh; Suthar, Kamlesh J; Mancini, Derrick C; Sankaranarayanan, Subramanian K R S
2014-03-14
Molecular dynamics simulations in conjunction with finite element calculations are used to explore the conformational dynamics of a thermo-sensitive oligomer, namely poly(N-isopropylacrylamide) (PNIPAM), subjected to an ultra-fast heating-cooling cycle. Finite element (FE) calculations were used to predict the temperature profile resulting from laser-induced heating of the polymer-aqueous system. The heating rate (∼0.6 K ps(-1)) deduced from FE calculations was used to heat an aqueous solution of PNIPAM consisting of 30 monomeric units (30-mer) from 285 K to 315 K. Non-equilibrium effects arising from the ultra-fast heating-cooling cycle results in a hysteresis during the coil-to-globule transition. The corresponding atomic scale conformations were characterized by monitoring the changes in the vibrational spectra, which provided a reliable metric to study the coil-to-globule transition in PNIPAM and vice-versa across the LCST. The vibrational spectra of bonds involving atoms from the oligomer backbone and the various side-groups (amide I, amide II, and the isopropyl group of PNIPAM) of the oligomers were analyzed to study the conformational changes in the oligomer corresponding to the observed hysteresis. The differences in the vibrational spectra calculated at various temperatures during heating and cooling cycles were used to understand the coil-to-globule and globule-to-coil transitions in the PNIPAM oligomer and identify the changes in the relative interactions between various atoms in the backbone and in the side groups of the oligomer with water. The shifts in the computed vibrational spectral peaks and the changes in the intensity of peaks for the different regions of PNIPAM, seen across the LCST during the heating cycle, are in good agreement with previous experimental studies. The changes in the radius of gyration (Rg) and vibrational spectra for amide I and amide II regions of PNIPAM suggest a clear coil-to-globule transition at ∼301 K during the
Barr, Elizabeth Lm; Maple-Brown, Louise J; Barzi, Federica; Hughes, Jaquelyne T; Jerums, George; Ekinci, Elif I; Ellis, Andrew G; Jones, Graham Rd; Lawton, Paul D; Sajiv, Cherian; Majoni, Sandawana W; Brown, Alex Dh; Hoy, Wendy E; O'Dea, Kerin; Cass, Alan; MacIsaac, Richard J
2017-04-01
The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation that combines creatinine and cystatin C is superior to equations that include either measure alone in estimating glomerular filtration rate (GFR). However, whether cystatin C can provide any additional benefits in estimating GFR for Indigenous Australians, a population at high risk of end-stage kidney disease (ESKD) is unknown. Using a cross-sectional analysis from the eGFR Study of 654 Indigenous Australians at high risk of ESKD, eGFR was calculated using the CKD-EPI equations for serum creatinine (eGFRcr), cystatin C (eGFRcysC) and combined creatinine and cystatin C (eGFRcysC+cr). Reference GFR (mGFR) was determined using a non-isotopic iohexol plasma disappearance technique over 4h. Performance of each equation to mGFR was assessed by calculating bias, % bias, precision and accuracy for the total population, and according to age, sex, kidney disease, diabetes, obesity and c-reactive protein. Data were available for 542 participants (38% men, mean [sd] age 45 [14] years). Bias was significantly greater for eGFRcysC (15.0mL/min/1.73m 2 ; 95% CI 13.3-16.4, pcreatinine remains the preferred equation in Indigenous Australians. Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.
Longitudinal Estimated GFR Trajectories in Patients With and Without Type 2 Diabetes and Nephropathy
DEFF Research Database (Denmark)
Weldegiorgis, Misghina; de Zeeuw, Dick; Li, Liang
2017-01-01
-renin-angiotensin-aldosterone-system antihypertensives were independently associated with a greater probability of a nonlinear eGFR trajectory. LIMITATIONS: Relatively short follow-up and no measured GFR. CONCLUSIONS: In both diabetes and nondiabetes trials, the majority of patients show a more or less linear eGFR decline. These data support...... with and without diabetes. STUDY DESIGN: Longitudinal observational study. SETTING & PARTICIPANTS: 6 clinical trials with repeated measurements of serum creatinine. PREDICTOR: Patient demographic and clinical parameters. OUTCOMES: Probability of nonlinear eGFR function trajectory calculated for each patient from...... a Bayesian model of individual eGFR trajectories. RESULTS: The median probability of a nonlinear eGFR decline in all trials was 0.26 (interquartile range, 0.13-0.48). The median probability was 0.28 in diabetes versus 0.09 in nondiabetes trials (P50% probability...
DIAGNOSIS OF FINANCIAL EQUILIBRIUM
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SUCIU GHEORGHE
2013-04-01
Full Text Available The analysis based on the balance sheet tries to identify the state of equilibrium (disequilibrium that exists in a company. The easiest way to determine the state of equilibrium is by looking at the balance sheet and at the information it offers. Because in the balance sheet there are elements that do not reflect their real value, the one established on the market, they must be readjusted, and those elements which are not related to the ordinary operating activities must be eliminated. The diagnosis of financial equilibrium takes into account 2 components: financing sources (ownership equity, loaned, temporarily attracted. An efficient financial equilibrium must respect 2 fundamental requirements: permanent sources represented by ownership equity and loans for more than 1 year should finance permanent needs, and temporary resources should finance the operating cycle.
GFR and Blood Lead Levels in Gas Station Workers Based on δ-Alad Gene Polymorphisms
Directory of Open Access Journals (Sweden)
Lantip Rujito
2015-04-01
showed that the proportion of ALAD genotype for ALAD 1-1, 1-2 and 2-2 were 94.7%, 5.3%, and 0% respectively. The mean of serum levels in homozygous 1-1 was 15.94 ppb and heterozygote 1-2 was 1.15 ppb. GFR of participants ranged from 71.11 mL/min to 185.20 mL/min with a mean of 117.34mL/min. There was no correlation between serum Pb and GFR (p = 0.19. Study also could not determine the correlation between GFR and ALAD gene Polymorphism. Discussion: Study then concluded that there was no correlation between blood lead levels in the GFR on each δ-ALAD genotypes. Keywords: Lead intoxication, GFR, δ-ALAD, gas station workers
[New topics regarding equations for GFR estimation based on serum creatinine and cystatin C].
Horio, Masaru
2014-02-01
Japanese GFR equations and CKD-EPI equations based on standardized serum creatinine and standardized cystatin C are recommended in recent Japanese CKD guides and KDIGO guidelines for CKD management, respectively. CKD-EPIcreat overestimates GFR in Japanese subjects, probably due to the difference in muscle mass between Japanese and Caucasians. Unlike CKD-EPIcreat, CKD-EPIcys performs well in Japanese subjects, indicating the advantages of using cystatin C as a GFR marker. KDIGO guidelines suggest measuring eGFRcys in adults with eGFRcreat of 45-59 ml/min/1.73 m2 who do not have markers of kidney damage if confirmation of CKD is required. Creatinine is excreted by glomerular filtration, but also secreted by the tubules. Alteration of the tubular secretion of creatinine may influence the performance of GFR equations based on serum creatinine. Multivariate analysis showed that GFR and serum albumin levels were independent parameters affecting the fractional excretion of creatinine (FE-Cr). Alteration of FE-Cr according to the serum albumin levels may be one of the reasons for the bias of GFR equations based on serum creatinine. Low GFR is a risk factor for all-cause and cardiovascular mortality in a general population. However, the relationship between eGFR and the hazard risk of events is different depending on whether cystatin C or creatinine is used to calculate eGFR. The association between eGFRcys and the hazard risk is much stronger compared with eGFRcreat. Cystatin C may be a useful alternative to creatinine for detecting a high risk of complications in a general population and subjects with CKD.
Fluctuations in eGFR in relation to unenhanced and enhanced MRI and CT outpatients
DEFF Research Database (Denmark)
Azzouz, Manal; Rømsing, Janne; Thomsen, Henrik S
2014-01-01
OBJECTIVE: To study fluctuations in estimated glomerular filtration rate (eGFR) in relation to contrast medium (CM) enhanced magnetic resonance imaging (MRI) and computed tomography (CT) compared to control groups in outpatients. MATERIALS AND METHODS: eGFR was determined right before the imaging......-induced nephropathy (CIN) requirement when the definition s-creatinine ≥44μmol/l (0.5mg/dl) was used. CONCLUSIONS: eGFR in outpatients undergoing MRI or CT did vary independently of whether the patient received contrast or not. The findings probably reflect the natural variations in s-creatinine levels. This should...
2013-01-01
Introduction Estimation of kidney function in critically ill patients with acute kidney injury (AKI), is important for appropriate dosing of drugs and adjustment of therapeutic strategies, but challenging due to fluctuations in kidney function, creatinine metabolism and fluid balance. Data on the agreement between estimating and gold standard methods to assess glomerular filtration rate (GFR) in early AKI are lacking. We evaluated the agreement of urinary creatinine clearance (CrCl) and three commonly used estimating equations, the Cockcroft Gault (CG), the Modification of Diet in Renal Disease (MDRD) and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, in comparison to GFR measured by the infusion clearance of chromium-ethylenediaminetetraacetic acid (51Cr-EDTA), in critically ill patients with early AKI after complicated cardiac surgery. Methods Thirty patients with early AKI were studied in the intensive care unit, 2 to 12 days after complicated cardiac surgery. The infusion clearance for 51Cr-EDTA obtained as a measure of GFR (GFR51Cr-EDTA) was calculated from the formula: GFR (mL/min/1.73m2) = (51Cr-EDTA infusion rate × 1.73)/(arterial 51Cr-EDTA × body surface area) and compared with the urinary CrCl and the estimated GFR (eGFR) from the three estimating equations. Urine was collected in two 30-minute periods to measure urine flow and urine creatinine. Urinary CrCl was calculated from the formula: CrCl (mL/min/1.73m2) = (urine volume × urine creatinine × 1.73)/(serum creatinine × 30 min × body surface area). Results The within-group error was lower for GFR51Cr-EDTA than the urinary CrCl method, 7.2% versus 55.0%. The between-method bias was 2.6, 11.6, 11.1 and 7.39 ml/min for eGFRCrCl, eGFRMDRD, eGFRCKD-EPI and eGFRCG, respectively, when compared to GFR51Cr-EDTA. The error was 103%, 68.7%, 67.7% and 68.0% for eGFRCrCl, eGFRMDRD, eGFRCKD-EPI and eGFRCG, respectively, when compared to GFR51Cr-EDTA. Conclusions The study
Energy Technology Data Exchange (ETDEWEB)
Anon.
1984-12-15
From 3-6 September the First International Workshop on Local Equilibrium in Strong Interaction Physics took place in Bad-Honnef at the Physics Centre of the German Physical Society. A number of talks covered the experimental and theoretical investigation of the 'hotspots' effect, both in high energy particle physics and in intermediate energy nuclear physics.
African Journals Online (AJOL)
context of antimicrobial therapy in malnutrition. Dialysis has in the past presented technical problems, being complicated and time-consuming. A new dialysis system based on the equilibrium technique has now become available, and it is the principles and practical application of this apparatus (Kontron Diapack; Kontron.
van Damme, E.E.C.
2000-01-01
An outcome in a noncooperative game is said to be self-enforcing, or a strategic equilibrium, if, whenever it is recommended to the players, no player has an incentive to deviate from it.This paper gives an overview of the concepts that have been proposed as formalizations of this requirement and of
Ismail, M.S.
2014-01-01
We introduce a new concept which extends von Neumann and Morgenstern's maximin strategy solution by incorporating `individual rationality' of the players. Maximin equilibrium, extending Nash's value approach, is based on the evaluation of the strategic uncertainty of the whole game. We show that
Development and validation of GFR-estimating equations using diabetes, transplant and weight
DEFF Research Database (Denmark)
Stevens, L.A.; Schmid, C.H.; Zhang, Y.L.
2009-01-01
interactions. Equations were developed in a pooled database of 10 studies [2/3 (N = 5504) for development and 1/3 (N = 2750) for internal validation], and final model selection occurred in 16 additional studies [external validation (N = 3896)]. RESULTS: The mean mGFR was 68, 67 and 68 ml/min/ 1.73 m(2......BACKGROUND: We have reported a new equation (CKD-EPI equation) that reduces bias and improves accuracy for GFR estimation compared to the MDRD study equation while using the same four basic predictor variables: creatinine, age, sex and race. Here, we describe the development and validation...... of this equation as well as other equations that incorporate diabetes, transplant and weight as additional predictor variables. METHODS: Linear regression was used to relate log-measured GFR (mGFR) to sex, race, diabetes, transplant, weight, various transformations of creatinine and age with and without...
Fluctuations in eGFR in relation to unenhanced and enhanced MRI and CT outpatients
Energy Technology Data Exchange (ETDEWEB)
Azzouz, Manal, E-mail: manalazzouz@gmail.com [Department of Diagnostic Radiology, Copenhagen University Hospital Herlev, Herlev Ringvej 75, DK 2730 Herlev (Denmark); Rømsing, Janne [Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen Ø (Denmark); Thomsen, Henrik S. [Department of Diagnostic Radiology, Copenhagen University Hospital Herlev, Herlev Ringvej 75, DK 2730 Herlev (Denmark)
2014-06-15
Objective: To study fluctuations in estimated glomerular filtration rate (eGFR) in relation to contrast medium (CM) enhanced magnetic resonance imaging (MRI) and computed tomography (CT) compared to control groups in outpatients. Materials and methods: eGFR was determined right before the imaging procedure and three days later at the department or at the patient's home. The iodine-based and gadolinium-based contrast media were the same as used for all other examinations at the department. Results: A total of 716 patients completed the study. There was a statistically significant, but not clinically relevant rise in eGFR after three days in all four groups. The average eGFR variation was 4.8 ml/min/1.73 m{sup 2}. There were large variations in eGFR between the two measurements in 45.8% of the patients as they had a change greater than ±10 ml/min/1.73 m{sup 2}. Only three patients fulfilled the contrast-induced nephropathy (CIN) requirement when the definition s-creatinine ≥44 μmol/l (0.5 mg/dl) was used. Conclusions: eGFR in outpatients undergoing MRI or CT did vary independently of whether the patient received contrast or not. The findings probably reflect the natural variations in s-creatinine levels. This should be taken into consideration when CIN is studied.
Fluctuations in eGFR in relation to unenhanced and enhanced MRI and CT outpatients
International Nuclear Information System (INIS)
Azzouz, Manal; Rømsing, Janne; Thomsen, Henrik S.
2014-01-01
Objective: To study fluctuations in estimated glomerular filtration rate (eGFR) in relation to contrast medium (CM) enhanced magnetic resonance imaging (MRI) and computed tomography (CT) compared to control groups in outpatients. Materials and methods: eGFR was determined right before the imaging procedure and three days later at the department or at the patient's home. The iodine-based and gadolinium-based contrast media were the same as used for all other examinations at the department. Results: A total of 716 patients completed the study. There was a statistically significant, but not clinically relevant rise in eGFR after three days in all four groups. The average eGFR variation was 4.8 ml/min/1.73 m 2 . There were large variations in eGFR between the two measurements in 45.8% of the patients as they had a change greater than ±10 ml/min/1.73 m 2 . Only three patients fulfilled the contrast-induced nephropathy (CIN) requirement when the definition s-creatinine ≥44 μmol/l (0.5 mg/dl) was used. Conclusions: eGFR in outpatients undergoing MRI or CT did vary independently of whether the patient received contrast or not. The findings probably reflect the natural variations in s-creatinine levels. This should be taken into consideration when CIN is studied
Leion, Felicia; Hegbrant, Josefine; den Bakker, Emil; Jonsson, Magnus; Abrahamson, Magnus; Nyman, Ulf; Björk, Jonas; Lindström, Veronica; Larsson, Anders; Bökenkamp, Arend; Grubb, Anders
2017-09-01
Estimating glomerular filtration rate (GFR) in adults by using the average of values obtained by a cystatin C- (eGFR cystatin C ) and a creatinine-based (eGFR creatinine ) equation shows at least the same diagnostic performance as GFR estimates obtained by equations using only one of these analytes or by complex equations using both analytes. Comparison of eGFR cystatin C and eGFR creatinine plays a pivotal role in the diagnosis of Shrunken Pore Syndrome, where low eGFR cystatin C compared to eGFR creatinine has been associated with higher mortality in adults. The present study was undertaken to elucidate if this concept can also be applied in children. Using iohexol and inulin clearance as gold standard in 702 children, we studied the diagnostic performance of 10 creatinine-based, 5 cystatin C-based and 3 combined cystatin C-creatinine eGFR equations and compared them to the result of the average of 9 pairs of a eGFR cystatin C and a eGFR creatinine estimate. While creatinine-based GFR estimations are unsuitable in children unless calibrated in a pediatric or mixed pediatric-adult population, cystatin C-based estimations in general performed well in children. The average of a suitable creatinine-based and a cystatin C-based equation generally displayed a better diagnostic performance than estimates obtained by equations using only one of these analytes or by complex equations using both analytes. Comparing eGFR cystatin and eGFR creatinine may help identify pediatric patients with Shrunken Pore Syndrome.
Chau, Nancy H.
2009-01-01
This paper presents a capability-augmented model of on the job search, in which sweatshop conditions stifle the capability of the working poor to search for a job while on the job. The augmented setting unveils a sweatshop equilibrium in an otherwise archetypal Burdett-Mortensen economy, and reconciles a number of oft noted yet perplexing features of sweatshop economies. We demonstrate existence of multiple rational expectation equilibria, graduation pathways out of sweatshops in complete abs...
International Nuclear Information System (INIS)
Li Baojun; Zhao Deshan
2014-01-01
Objective: To compare and analyze the difference of measured glomerular filtration rate (GFR) of ectopic pelvic kidney between anterior and posterior imaging processing in renal dynamic imaging. Methods: There were 10 patients collected retrospectively, with ectopic kidneys in pelvic cavity confirmed by ultrasound, CT, renal dynamic imaging and other imaging modalities. All images of ectopic kidneys in renal dynamic imaging were processed by anterior and posterior methods respectively. The ectopic kidney was only processed in anterior imaging, ectopic kidney and contralateral normal kidney were processed in posterior imaging. Total GFR equalled the sum of GFR of normal kidney in posterior imaging and GFR of ectopic kidney in anterior imaging, was compared with total GFR of two kidneys in posterior imaging and GFR in two-sample method. All correlation analysis were completed between GFRs from three methods and all patients were followed up. Statistically paired t-test and bivariate correlation analysis test were used. Results: The mean GFR of ectopic kidney in anterior imaging equal to (27.48±12.24) ml/(min · 1.73 m 2 ). It was more than GFR [(10.71 ±4.74) ml/ (min · 1.73 m 2 )] in posterior imaging above 46% (t=5.481, P<0.01). There was no significant difference (t=-2.238, P>0.05), but better correlation (r=0.704, P<0.05) between total GFR in anterior imaging and GFR in two-sample method. There was significant difference (t=4.629, P<0.01)and worse correlation (r=0.576, P>0.05) between total GFR in posterior imaging and GFR in two-sample method. Conclusion: Comparing with GFR in posterior imaging, GFR in anterior imaging can more truly reflect function condition of ectopic pelvic kidney in renal dynamic imaging. (authors)
International Nuclear Information System (INIS)
Perusquia, R.; Ortiz, J.J.; Montes, J.L.
2003-01-01
Nowadays in the National Institute of Nuclear Research are carried out studies with some bio-inspired optimization techniques to improve the performance of the fuel cycles of the boiling water reactors of the Laguna Verde power plant (CLV). In the present work two bio-inspired techniques were applied with the purpose of improving the performance of a balance cycle of 18 months developed for the CLV: genetic algorithms (AG) and systems based on ants colonies (SCH). The design of the reference cycle it represents in several aspects an optimal cycle proposed starting from the experience of several operation decades with the boiling water reactors (BWR initials for Boiling Water Reactor) in the world. To try to improve their performance is beforehand a difficult challenge and it puts on test the feasibility of the optimization methods in the reloads design. The study of the bio-inspired techniques was centered exclusively on the obtaining of the control rod patterns (PBC) trying to overcome the capacity factor reached in the design of the reference cycle. It was fixed the cycle length such that the decrease of the coast down period would represent an increase of the capacity factor of the cycle; so that, it diminishes the annual cost associated with the capital cost of the plant. As consequence of the study, was found that the algorithm based on the ants colonies reaches to diminish the coast down period in five and half days respect to the original balance cycle, what represents an annual saving of $US 74,000. Since the original cycle was optimized, the above-mentioned, shows the ability of the SCH for the optimization of the cycle design. With the AG it was reach to approach to the original balance cycle with a coast down period greater in seven days estimating an annual penalization of $US 130,000. (Author)
Recording blood pressure and eGFR in primary care after the Belgrade screening study.
Lezaic, Visnja; Marinkovic, Jelena; Milutinovic, Zoran; Jovanovic-Vasiljevic, Nada; Vujicic, Vesna; Pejovic, Branka; Kalabic, Snezana; Djukanovic, Ljubica
2018-11-01
In 2009, Belgrade nephrologists and general practitioners from thirteen health centers carried out screening for chronic kidney disease (CKD). Three years later, medical records of patients from four health centers participating in the screening study were retrospectively analyzed in order to check whether general practitioners had continued to control patients at risk for CKD in accordance with the recommendations provided. The study included 460 patients who visited their doctor at least once in the three-year period. Data on blood pressure, ACEI use, estimated glomerular filtration rate (eGFR) and comorbidities were taken from patients' medical records. Blood pressure was not recorded in any of the three years in 42.8% and eGFR in 36.7% of the patients, but blood pressure was registered every year in 7.8% and eGFR in 4.3% of them. Over the three years, the relative number of patients with recorded blood pressure decreased from 41.7% to 17.8%, and with recorded eGFR from 41.7% to 21.5%. Multivariate linear regression found that Health Center, systolic and diastolic blood pressure and presence of hypertension were negatively associated with number of years with recorded blood pressure. Health Center, systolic blood pressure and sum of years with recorded eGFR below 60 ml/min/1.73m 2 were associated with number of years with recorded eGFR. Under-recording of blood pressure and eGFR in primary care health centers suggests lack of adherence to current guidelines and insufficient care of CKD patients. This implies the necessity for continuous education of physicians.
A method to eliminate the effect of protein binding on GFR
International Nuclear Information System (INIS)
Prabakaran, K.; Fernandes, V.; Nour, R.
1998-01-01
Full text: Plasma clearance of 99m Tc-DTPA is a standard method for GFR assessment. Protein binding (PB) of 99m Tc-DTPA is thought to affect the accuracy of the GFR measurement. Therefore, eliminating PB portion would improve the accuracy of this measurement. Methods to eliminate PB are usually complex, but a simple Amicon micropartition system has been proposed to eliminate the PB effect. This study is aimed to assess if this simple method effectively excluded the PB fraction and improved the accuracy of the GFR measurement. Therefore, eliminating PB portion would improve the accuracy of this measurement. Methods to eliminate PB are usually complex, but a simple Amicon micropartition system separates free 99m Tc-DTPA from the PB fraction after a 10 min centrifugation of patient plasma. The ultrafiltrate obtained is totally free of PB 99m Tc-DTPA. 20 consecutive patients had GFRs performed using the two sample method with blood drawn at 60 and 150 min. All samples had an Ultrafiltrate 99m Tc-DTPA and normal plasma 99m Tc-DTPA. The GFRs were calculated from both samples. The findings showed a mean PB of 6.5 + 3.9% and 13 + 5.0% at 60 min and 150 min respectively for our DTPA. The mean GFR from normal plasma 85.7 + 26.4 mL/min and from ultrafiltrate = 97.2 + 28.8 mL/min. Statistical analysis using Student''s ''t'' test shows that there is a significant difference between the values of GFR (P < 0.05). Our result confirms that the PB of DTPA is substantial and affects the GFR estimation significantly. The method of ultrafiltration eliminates the PB, and very simple to use. This method could be used on a routine basis and/or to assess the suitability of the DTPA used in various departments for GFR measurement
Expression of GDNF and GFR alpha 1 in mouse taste bud cells.
Takeda, Masako; Suzuki, Yuko; Obara, Nobuko; Uchida, Nobuhiko; Kawakoshi, Kentaro
2004-11-01
GDNF (glial cell line-derived neurotrophic factor) affects the survival and maintenance of central and peripheral neurons. Using an immunocytochemical method, we examined whether the taste bud cells in the circumvallate papillae of normal mice expressed GDNF and its GFR alpha 1 receptor. Using double immunostaining for either of them and NCAM, PGP 9.5, or alpha-gustducin, we additionally sought to determine what type of taste bud cells expressed GDNF or GFR alpha 1, because NCAM is reported to be expressed in type-III cells, PGP 9.5, in type-III and some type-II cells, and alpha-gustducin, in some type-II cells. Normal taste bud cells expressed both GDNF and GFR alpha 1. The percentage of GDNF-immunoreactive cells among all taste bud cells was 31.63%, and that of GFR alpha 1-immunoreactive cells, 83.21%. Confocal laser scanning microscopic observations after double immunostaining showed that almost none of the GDNF-immunoreactive cells in the taste buds were reactive with anti-NCAM or anti-PGP 9.5 antibody, but could be stained with anti-alpha-gustducin antibody. On the other hand, almost all anti-PGP 9.5- or anti-alpha-gustducin-immunoreactive cells were positive for GFR alpha 1. Thus, GDNF-immunoreactive cells did not include type-III cells, but type-II cells, which are alpha-gustducin-immunoreactive; on the other hand, GFR alpha 1-immunoreactive cells included type-II and -III cells, and perhaps type-I cells. We conclude that GDNF in the type-II cells may exert trophic actions on type-I, -II, and -III taste bud cells by binding to their GFR alpha 1 receptors.
Luca Anderlini; Daniele Terlizzese
2009-01-01
We build a simple model of trust as an equilibrium phenomenon, departing from standard "selfish" preferences in a minimal way. Agents who are on the receiving end of an other to transact can choose whether to cheat and take away the entire surplus, taking into account a "cost of cheating." The latter has an idiosyncratic component (an agent's type), and a socially determined one. The smaller the mass of agents who cheat, the larger the cost of cheating suffered by those who cheat. Depending o...
Energy Technology Data Exchange (ETDEWEB)
1981-11-01
Program accomplishments in a continuing effort to demonstrate the feasibility of direct coal-fired, closed-cycle MHD power generation are reported. This volume contains the following appendices: (A) user's manual for 2-dimensional MHD generator code (2DEM); (B) performance estimates for a nominal 30 MW argon segmented heater; (C) the feedwater cooled Brayton cycle; (D) application of CCMHD in an industrial cogeneration environment; (E) preliminary design for shell and tube primary heat exchanger; and (F) plant efficiency as a function of output power for open and closed cycle MHD power plants. (WHK)
Liu, Xun; Li, Ning-shan; Lv, Lin-sheng; Huang, Jian-hua; Tang, Hua; Chen, Jin-xia; Ma, Hui-juan; Wu, Xiao-ming; Lou, Tan-qi
2013-12-01
Accurate estimation of glomerular filtration rate (GFR) is important in clinical practice. Current models derived from regression are limited by the imprecision of GFR estimates. We hypothesized that an artificial neural network (ANN) might improve the precision of GFR estimates. A study of diagnostic test accuracy. 1,230 patients with chronic kidney disease were enrolled, including the development cohort (n=581), internal validation cohort (n=278), and external validation cohort (n=371). Estimated GFR (eGFR) using a new ANN model and a new regression model using age, sex, and standardized serum creatinine level derived in the development and internal validation cohort, and the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) 2009 creatinine equation. Measured GFR (mGFR). GFR was measured using a diethylenetriaminepentaacetic acid renal dynamic imaging method. Serum creatinine was measured with an enzymatic method traceable to isotope-dilution mass spectrometry. In the external validation cohort, mean mGFR was 49±27 (SD) mL/min/1.73 m2 and biases (median difference between mGFR and eGFR) for the CKD-EPI, new regression, and new ANN models were 0.4, 1.5, and -0.5 mL/min/1.73 m2, respectively (P30% from mGFR) were 50.9%, 77.4%, and 78.7%, respectively (Psource of systematic bias in comparisons of new models to CKD-EPI, and both the derivation and validation cohorts consisted of a group of patients who were referred to the same institution. An ANN model using 3 variables did not perform better than a new regression model. Whether ANN can improve GFR estimation using more variables requires further investigation. Copyright © 2013 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.
Molitoris, Bruce A.
2017-01-01
Chronic kidney disease (CKD) remains an increasing clinical problem. Although clinical risk factors and biomarkers for development and progression of CKD have been identified, there is no commercial surveillance technology to definitively diagnose and quantify the severity and progressive loss of glomerular filtration rate (GFR) in CKD. This has limited the study of potential therapies to late stages of CKD when FDA-registerable events are more likely. Since patient outcomes, including the rate of CKD progression, correlate with disease severity, and effective therapy may require early intervention, being able to diagnose and stratify patients by their level of decreased kidney function early on is key for translational progress. In addition, renal reserve, defined as the increase in GFR following stimulation, may improve the quantification of GFR based solely on basal levels. Various groups are developing and characterizing optical measurement techniques utilizing new minimally invasive or non-invasive approaches for quantifying basal and stimulated kidney function. This development has the potential to allow widespread individualization of therapy at an earlier disease stage. Therefore, the purposes of this review are to suggest why quantifying stimulated GFR, by activating renal reserve, may be advantageous in patients and review fluorescent technologies to deliver patient-specific GFR. PMID:28223001
Directory of Open Access Journals (Sweden)
Domenico Santoro
2014-12-01
Full Text Available Background/Aims: Accurate staging of chronic kidney disease (CKD is very important. We tried to identify difference in GFR evaluation between CKD-EPI and Gates method with renal scintigraphy and which variables are associated with these differences. Methods: We retrospectively reviewed the records of 341 patients who underwent dynamic renal scintigraphy in the last 5 years. Patients were categorized according to KDIGO staging I to V, using the eGFR calculated with the CKD-EPI equation. Secondarily, we stratified patients according to treatment with renin-angiotensin system (RAS inhibitors. Results: Gates method tends to underestimate GFR especially in CKD stage I (mean -22.2 ml/min and II (mean -12.5 ml/min. The division in quartiles of ages showed an underestimation of GFR only in the first quartile of age (Conclusion: The assessment of GFR by the Gates method must be carefully considered in the early stages of CKD, especially in younger patients. Moreover, the difference is more pronounced in patients treated with RAS inhibitors. Longitudinal studies will prove which method better predicts cardiovascular or renal events.
de Oliveira, Mário J
2017-01-01
This textbook provides an exposition of equilibrium thermodynamics and its applications to several areas of physics with particular attention to phase transitions and critical phenomena. The applications include several areas of condensed matter physics and include also a chapter on thermochemistry. Phase transitions and critical phenomena are treated according to the modern development of the field, based on the ideas of universality and on the Widom scaling theory. For each topic, a mean-field or Landau theory is presented to describe qualitatively the phase transitions. These theories include the van der Waals theory of the liquid-vapor transition, the Hildebrand-Heitler theory of regular mixtures, the Griffiths-Landau theory for multicritical points in multicomponent systems, the Bragg-Williams theory of order-disorder in alloys, the Weiss theory of ferromagnetism, the Néel theory of antiferromagnetism, the Devonshire theory for ferroelectrics and Landau-de Gennes theory of liquid crystals. This new edit...
'Scan GFR' as an alternative to 51Cr-EDTA clearance
International Nuclear Information System (INIS)
Osman, E.A.; Clarke, M.B.; Barrett, J.J.; Parsons, V.; Dulwich Hospital, London
1989-01-01
In this report 39 patients had their GFR assessed by 51 Cr-EDTA in a single shot-multiple sampling technique and also by measuring the quantitative renal uptake of 99m Tc-DTPA during a standard renal imaging test. The results showed a correlation coefficient of 0.96 between the two techniques. By using linear regression analysis the GFR was derived from the % renal uptake of DTPA in a further series of 24 patients in whom the 51 Cr-EDTA method was also employed. The two methods were compared and showed a correlation coefficient of 0.94 with a mean GFR difference of 7 ± 4.5 ml/min over a 51 Cr-EDTA range of 38-150 ml/min. (orig.) [de
Effect of food and activity on the reproducibility of isotopic GFR estimation
International Nuclear Information System (INIS)
Wilkinson, J.; Fleming, J.S.; Waller, D.G.
1990-01-01
The reproducibility of the plasma clearance of 99 Tc m DTPA was studied in 26 patients under standardized conditions with the subject fasting and at rest. The coefficient of variation of duplicate measurements in patients with glomerular filtration rates (GRFs) ranging from 11-103 ml min -1 was 8%. Mean GFR following a breakfast containing 670 kcal and 31 g protein was increased significantly from 40.7±28.1 ml min -1 to 43.6±30.8 ml min -1 . When fasted but permitted free exercise there was no consistent trend in GFR but the coefficient of variation of duplicate estimates increased significantly to 12.1%. It is recommended that routine GFR measurement should be carried out fasting or following a light diet with restricted activity. (author)
Cystatin C levels in healthy kidney donors and its correlation with GFR by creatinine clearance
International Nuclear Information System (INIS)
Ayub, S.; Khan, S.; Zafar, M.N.
2014-01-01
Objective: To determine Serum Cystatin C (S.CysC) levels in healthy potential kidney donors and its correlation with Serum Creatinine (S.Cr), Glomerular filtration rate (GFR) by 24 hour urinary Creatinine clearance (CCL) and GFR by formulae of Cockcroft Gault (CCG) and Modification of diet in Renal Disease (MDRD). Methods: A Cross sectional study was conducted at Sindh Institute of Urology and Transplantation (SIUT), Karachi, between June and December 2012. One hundred and three potential healthy kidney donors were enrolled in the study to measure their S.CysC and correlate it with S.Cr, CCL and GFR by CCG and MDRD. Statistical analysis was done by SPSS 17. Results: The mean age of the healthy kidney donors was 32.19+8.27 years with a M:F ratio of 1.86:1. The mean Serum Creatinine (S.Cr) was 0.86+0.18 mg/dl and mean S.CysC was 0.88+0.12 mg/dl. S.CysC showed significant correlation with S.Cr (r = 0.78, p<0.001), CCL (r = 0.67, p<0.001), GFR CCG (r = 0.54, p<0.001) and GFR MDRD (r = 0.67, p<0.001). Correlation of S.CysC was better than S.Cr for CCL, S.Cr (0.60) vs S.CysC (0.67) and GFR CCG, S.Cr (0.41) vs S.CysC (0.54). Correlation was comparable for MDRD, S.Cr (0.67) vs S.Cys (0.67). Conclusion: S.CysC is better marker of kidney function in potential healthy kidney donors. It is a reliable, convenient and economical marker that can be used especially in routine clinical practice. (author)
Effect of Genetic African Ancestry on eGFR and Kidney Disease
Nadkarni, Girish N.; Belbin, Gillian; Lotay, Vaneet; Wyatt, Christina; Gottesman, Omri; Bottinger, Erwin P.; Kenny, Eimear E.; Peter, Inga
2015-01-01
Self-reported ancestry, genetically determined ancestry, and APOL1 polymorphisms are associated with variation in kidney function and related disease risk, but the relative importance of these factors remains unclear. We estimated the global proportion of African ancestry for 9048 individuals at Mount Sinai Medical Center in Manhattan (3189 African Americans, 1721 European Americans, and 4138 Hispanic/Latino Americans by self-report) using genome-wide genotype data. CKD-EPI eGFR and genotypes of three APOL1 coding variants were available. In admixed African Americans and Hispanic/Latino Americans, serum creatinine values increased as African ancestry increased (per 10% increase in African ancestry, creatinine values increased 1% in African Americans and 0.9% in Hispanic/Latino Americans; P≤1x10−7). eGFR was likewise significantly associated with African genetic ancestry in both populations. In contrast, APOL1 risk haplotypes were significantly associated with CKD, eGFRblack on the basis of ≥50% African ancestry resulted in higher eGFR for 14.7% of Hispanic/Latino Americans and lower eGFR for 4.1% of African Americans, affecting CKD staging in 4.3% and 1% of participants, respectively. Reclassified individuals had electrolyte values consistent with their newly assigned CKD stage. In summary, proportion of African ancestry was significantly associated with normal-range creatinine and eGFR, whereas APOL1 risk haplotypes drove the associations with CKD. Recalculation of eGFR on the basis of genetic ancestry affected CKD staging and warrants additional investigation. PMID:25349204
Energy Technology Data Exchange (ETDEWEB)
Bandura, A.V. [National Politechnical Univ., Kiev (Ukraine); Brodianskii, V.M. [Moscow Power Engineering Inst. Technical Univ. (Russian Federation)
1996-11-01
The main problem of exergy application directly in economic analysis is to find valid correlation between money-based cost and exergy based one (including exergy expenses of labour) and to define exergy cost as an economic category among the existing traditional economic ones. The present report is aimed to search the way for this macroeconomic problems` solution. It is demonstrated that exergy-based cost can be recalculated in a monetary form using a coefficient, defined as a ratio between money supply and the total exergy of all natural resources involved in production process, i.e. as a ratio between monetary and exergy bases. The difference between `natural` and current prices (P) can be used directly both for general quantitative characteristics of an economic cycles driving force and for control of market relationship imperfection. It is shown that for the period of time with the positive P, that is, current price is lower than a `natural` one, the recoveries in business cycles are observed. For the period of time with the negative P, that is, current price is higher than a natural one, economic recessions are observed. The moment of time when P = 0 corresponds to the turning point of a business cycle. In such a way the possibility to predict the turning points of business cycles is demonstrated. 14 refs, 2 figs, 2 tabs
Energy Technology Data Exchange (ETDEWEB)
1981-11-01
Program accomplishments in a continuing effort to demonstrate the feasibility of direct coal fired, closed cycle, magnetohydrodynamic power generation are detailed. These accomplishments relate to all system aspects of a CCMHD power generation system including coal combustion, heat transfer to the MHD working fluid, MHD power generation, heat and cesium seed recovery and overall systems analysis. Direct coal firing of the combined cycle has been under laboratory development in the form of a high slag rejection, regeneratively air cooled cyclone coal combustor concept, originated within this program. A hot bottom ceramic regenerative heat exchanger system was assembled and test fired with coal for the purposes of evaluating the catalytic effect of alumina on NO/sub x/ emission reduction and operability of the refractory dome support system. Design, procurement, fabrication and partial installation of a heat and seed recovery flow apparatus was accomplished and was based on a stream tube model of the full scale system using full scale temperatures, tube sizes, rates of temperature change and tube geometry. Systems analysis capability was substantially upgraded by the incorporation of a revised systems code, with emphasis on ease of operator interaction as well as separability of component subroutines. The updated code was used in the development of a new plant configuration, the Feedwater Cooled (FCB) Brayton Cycle, which is superior to the CCMHD/Steam cycle both in performance and cost. (WHK)
Estimated GFR Decline as a Surrogate End Point for Kidney Failure
DEFF Research Database (Denmark)
Lambers Heerspink, Hiddo J; Weldegiorgis, Misghina; Inker, Lesley A
2014-01-01
A doubling of serum creatinine value, corresponding to a 57% decline in estimated glomerular filtration rate (eGFR), is used frequently as a component of a composite kidney end point in clinical trials in type 2 diabetes. The aim of this study was to determine whether alternative end points defin...
Cystatin C Falsely Underestimated GFR in a Critically Ill Patient with a New Diagnosis of AIDS
Directory of Open Access Journals (Sweden)
Caitlin S. Brown
2016-01-01
Full Text Available Cystatin C has been suggested to be a more accurate glomerular filtration rate (GFR surrogate than creatinine in patients with acquired immunodeficiency syndrome (AIDS because it is unaffected by skeletal muscle mass and dietary influences. However, little is known about the utility of this marker for monitoring medications in the critically ill. We describe the case of a 64-year-old female with opportunistic infections associated with a new diagnosis of AIDS. During her course, she experienced neurologic, cardiac, and respiratory failure; yet her renal function remained preserved as indicated by an eGFR ≥ 120 mL/min and a urine output > 1 mL/kg/hr without diuresis. The patient was treated with nephrotoxic agents; therefore cystatin C was assessed to determine if cachexia was resulting in a falsely low serum creatinine. Cystatin C measured 1.50 mg/L which corresponded to an eGFR of 36 mL/min. Given the >60 mL/min discrepancy, serial 8-hour urine samples were collected and a GFR > 120 mL/min was confirmed. It is unclear why cystatin C was falsely elevated, but we hypothesize that it relates to the proinflammatory state with AIDS, opportunistic infections, and corticosteroids. More research is needed before routine use of cystatin C in this setting can be recommended.
LENUS (Irish Health Repository)
He, Xiang
2009-02-15
To date, efforts have focused on assessing estimated glomerular filtration rate (eGFR) formulae against measured GFR. However, a more appropriate clinical gold standard is one conveying a defined clinical disadvantage. In renal transplantation, these measures are mortality and graft failure.
International Nuclear Information System (INIS)
Shimoji, Keigo; Aoki, Shigeki; Nakanishi, Atsushi
2012-01-01
The aim of this study was to elucidate the distribution of estimated glomerular filtration rate (eGFR) values in patients who underwent gadolinium-based contrast agent (GBCA)-enhanced magnetic resonance imaging (MRI) at different types of hospitals. We retrospectively studied 2,550 patients who underwent MRI at five institutions. We recorded the date and value of each patient's eGFR test. The distribution of eGFR values was compared with that in the general Japanese population. A total of 84.3% of patients had their eGFRs evaluated before GBCA-enhanced MRI. Of these, 84.7% were evaluated within 3 months before the GBCA-enhanced MRI, and 1.3% were evaluated on the day of the GBCA-enhanced MRI. A total of 87.2% of patients tested had an eGFR of ≥60 ml/min/1.73 m 2 ; 12.8% had an eGFR of 2 , and no patients had an eGFR of 2 . The rate of renal function evaluation differed among hospitals. The prevalence of low eGFR values was greater in Juntendo Tokyo Koto Geriatric Medical Center than in the other hospitals, and the prevalence of low eGFR values was greater in patients who underwent GBCA-enhanced MRI than in the general Japanese population. (author)
Directory of Open Access Journals (Sweden)
Paweł Wróbel
2018-03-01
Conclusions: CKD-EPI and abbreviated MDRD formulas have a similar usefulness in GFR value estimation in patients with diagnosed chronic kidney disease. Lower eGFR values achieved using abbreviated MDRD formula and CKD-EPI equation in comparison with Bjornsson’s formula may result in an increased number of patients diagnosed with CKD.
International Nuclear Information System (INIS)
Mahlstedt, J.; Muehlbauer, J.; Schrott, K.H.; Wolf, F.
1982-01-01
A technique measuring external radiation with semiconductor minidetectors (SCM) by use of a portable solid state memory after bolus injection of 1mCi 99mTc-DTPA is described. The correlation of the calculated clearances to plasma creatinine levels and to endogenous creatinine clearance as well is satisfactory. This new technique is compared with a standard steady state technique (GFR-SS) using 51 Cr-EDTA. GFR-SCM is strongly correlated to GFR-SS as standard method, therefore the data provides substantial evidence that GFR-SCM is a reliable method of GFR measurement. The advantages are: fast availability of the test result especially when calculated by use of a minicomputer; ease of performance in routine work; convenience for the patient without need of compliance and low costs for the detector system
Sinha-Hikim, I; Arver, S; Beall, G; Shen, R; Guerrero, M; Sattler, F; Shikuma, C; Nelson, J C; Landgren, B M; Mazer, N A; Bhasin, S
1998-04-01
Measurements of total and free testosterone levels in women have lacked precision and accuracy because of limited assay sensitivity. The paucity of normative data on total and free testosterone levels in healthy women has confounded interpretation of androgen levels in women with human immunodeficiency virus (HIV) infection and other disease states. Therefore, the objectives of this study were to develop sensitive assays for the measurement of the low total and free testosterone levels in women to define the range for these hormones during the normal menstrual cycle and assess the total and free testosterone levels in HIV-infected women. By using a larger volume of serum, increasing the incubation time, and reducing the antibody concentration, the sensitivity of the total testosterone assay was increased to 0.008 nmol/L, and that of the free testosterone assay was increased to 2 pmol/L. The mean percent free testosterone was 1.0 +/- 0.1% of the total testosterone. Serum total and free testosterone levels in the follicular and luteal phases were not significantly different, but both demonstrated a modest preovulatory increase, 3 days before the LH peak. Serum total [0.50 +/- 0.32 (14.60 +/- 9.22) vs. 1.2 +/- 0.7 nmol/L (34.3 +/- 21.0 ng/dL); P copy number. Serum FSH, but not LH, levels were significantly higher in HIV-infected women than in controls. Using assays with sufficient sensitivity, we defined the range for total and free testosterone levels during the normal menstrual cycle. Serum total and free testosterone levels are lower in HIV-infected women and correlate inversely with plasma HIV ribonucleic acid levels. The hypothesis that androgen deficiency contributes to wasting in HIV-infected women remains to be tested.
Energy Technology Data Exchange (ETDEWEB)
Girardin, G.
2009-07-15
During the past ten years, different independent factors, such as the rapidly increasing worldwide demand in energy, societal concerns about greenhouse gas emissions, and the high and volatile prices for fossil fuels, have contributed to the renewed interest in nuclear technology. In this context, the Generation IV International Forum (GIF) launched the initiative to collaborate on the research and development efforts needed for the next generation of nuclear reactors. A particular goal set for Generation IV systems is closure of the nuclear fuel cycle; they are expected to offer a better utilization of natural resources, as also a minimization of long-lived radioactive wastes. Among the systems selected by the GIF, the Gas-cooled Fast Reactor (GFR) is a highly innovative system with advanced fuel geometry and materials. The principal aim of the present research is to develop and qualify the control assembly (CA) pattern and corresponding CA implementation scheme for the 2400 MWth reference GFR design. The work has been carried out in three successive phases: (1) validation of the neutronics tools, (2) the CA pattern development and related static analysis, and (3) dynamic core behaviour studies for hypothetical CA driven transients. The deterministic code system ERANOS and its associated nuclear data libraries for fast reactors were developed and validated for sodium-cooled reactors. In order to validate ERANOS for GFR applications, a systematic reanalysis of the GFR-relevant integral data generated at PSI during the GCFR-PROTEUS experimental program of the 1970’s was undertaken. The reference PROTEUS test lattice has been analyzed with ERANOS-2.0 and its associated, adjusted nuclear data library ERALIB1. Benchmark calculations were performed with the Monte Carlo code MCNPX, allowing one to both check the deterministic results and to analyze the sensitivity to different modern data libraries. For the main reaction rate ratios, the new analysis of the GCFR
International Nuclear Information System (INIS)
Girardin, G.
2009-07-01
During the past ten years, different independent factors, such as the rapidly increasing worldwide demand in energy, societal concerns about greenhouse gas emissions, and the high and volatile prices for fossil fuels, have contributed to the renewed interest in nuclear technology. In this context, the Generation IV International Forum (GIF) launched the initiative to collaborate on the research and development efforts needed for the next generation of nuclear reactors. A particular goal set for Generation IV systems is closure of the nuclear fuel cycle; they are expected to offer a better utilization of natural resources, as also a minimization of long-lived radioactive wastes. Among the systems selected by the GIF, the Gas-cooled Fast Reactor (GFR) is a highly innovative system with advanced fuel geometry and materials. The principal aim of the present research is to develop and qualify the control assembly (CA) pattern and corresponding CA implementation scheme for the 2400 MWth reference GFR design. The work has been carried out in three successive phases: (1) validation of the neutronics tools, (2) the CA pattern development and related static analysis, and (3) dynamic core behaviour studies for hypothetical CA driven transients. The deterministic code system ERANOS and its associated nuclear data libraries for fast reactors were developed and validated for sodium-cooled reactors. In order to validate ERANOS for GFR applications, a systematic reanalysis of the GFR-relevant integral data generated at PSI during the GCFR-PROTEUS experimental program of the 1970’s was undertaken. The reference PROTEUS test lattice has been analyzed with ERANOS-2.0 and its associated, adjusted nuclear data library ERALIB1. Benchmark calculations were performed with the Monte Carlo code MCNPX, allowing one to both check the deterministic results and to analyze the sensitivity to different modern data libraries. For the main reaction rate ratios, the new analysis of the GCFR
Energy Technology Data Exchange (ETDEWEB)
Salaices, M.; Sandoval, S.; Ovando, R. [Instituto de Investigaciones Electricas. Gerencia de Energia Nuclear, Av. Reforma 113 Col. Palmira. 62490 Cuernavaca, Morelos (Mexico)]. e-mail: sal@iie.org.mx
2007-07-01
Presently work the {beta} and {gamma} radiation decay profiles for a radionuclides inventory in equilibrium cycle of a BWR type reactor is presented. The profiles are presented in terms of decay in the activity of the total inventory as well as of the chemical groups that conform the inventory. In the obtaining of the radionuclides inventory in equilibrium cycle the ORIGEN2 code, version 1 was used, which simulates fuel burnup cycles and it calculates the evolution of the isotopic composition as a result of the burnt one, irradiation and decay of the nuclear fuel. It can be observed starting from the results that the decrease in the activity for the initial inventory and the different chemical groups that conform it is approximately proportional to the base 10 logarithm of the time for the first 24 hours of having concluded the burnt one. It can also be observed that the chemical groups that contribute in more proportion to the total activity of the inventory are the lanthanides-actinides and the transition metals, with 39% and 28%, respectively. The groups of alkaline earth metals, halogens, metalloids, noble gases and alkaline metals, contribute with percentages that go from the 8 to 5%. The groups that less they contribute to the total activity of the inventory they are the non metals and semi-metals with smaller proportions that 1%. The chemical groups that more contribute to the energy of {beta} and {gamma} radiation its are the transition metals and the lanthanides-actinides with a change in the order of importance at the end of the 24 hours period. The case of the halogens is of relevance for the case of the {gamma} radiation energy due that occupying the very near third site to the dimensions of the two previous groups. Additionally, the decay in the activity for the total inventory and the groups that conform it can be simulated by means of order 6 polynomials or smaller than describe its behavior appropriately. The results presented in this work, coupled
Neutronic evaluation of transuranics in a GFR model using MCNPX and scale 6.0
Energy Technology Data Exchange (ETDEWEB)
Macedo, Anderson A.P.; Castro, Victor F.; Silva, Clarysson A.M. da; Velasquez, Carlos E.; Pereira, Claubia, E-mail: macedo@nuclear.ufmg.br, E-mail: victorfariacastro@gmail.com, E-mail: clarysson@nuclear.ufmg.br, E-mail: carlosvelcab@ufmg.br, E-mail: claubia@nuclear.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear
2017-11-01
In this study, a GFR core model with 100 MWt was evaluated using three different fuel compositions: a conventional (U, Pu)C and two reprocessed fuels reprocessed by UREX+ technique one spiked with depleted uranium, (U,TRU)C, and the other one reprocessed spiked with thorium, (Th,TRU)C. The reprocessed fuel came from a PWR standard fuel (33,000 MWd/T burned) with 3.1% of initial enrichment and left in the pool by 5 years. Some important nuclides were followed during burnup and k{sub inf} was evaluated for 1400 days. The results also include analysis of the B4C insertion and the temperature coefficient. The simulations were performed comparing results between MCNPX and SCALE 6.0 codes. The main goal is to validate the model and evaluate the possibility to use TRU spiked with Th in a GFR. (author)
International Nuclear Information System (INIS)
Zhang Li; Li Sumei; Zhang Rong; Zhai Fei
2010-01-01
Objective: To study the diagnostic value of determination of glomerular filtration rate (GFR), Urinary albumin (UAlb) and UAlb/UCr for early diabetic nephropathy in patients with type 2 Diabetes. Methods: UAlb, UAlb/UCr were measured with radioimmunoassay (RIA) and GFR measured with Tcm DTPA dynamic renal imaging in 102 DM2 patients with diabetic nephropathy (DN) and 23 DM2 patients without nephropathy. Results: In diabetics with nephropathy with a disease course of less than five years (n=38), the GFR, UAlb/UCr were significantly higher than those in diabetics without nephropathy. With prolongation of the disease, GFR gradually declined and UAlb/UCr rose further and in patients with nephropathy with disease courses over 10 years, the GFR was significantly lower and UAlb/UCr significantly higher than those in diabetics without nephropathy (all P<0.05). The GFR was negatively correlated with course of disease, BMI and UAlb/UCr (r=-0.691, -0.631, -0.698, respectively, P<0.01). Conclusion: GFR can reflect the degree of renal damage of diabetic patients,and may be helpful for evaluation of progression of DN when combined with assay of albuminuria. (authors)
Association of Reduced eGFR and Albuminuria with Serious Fall Injuries among Older Adults.
Bowling, C Barrett; Bromfield, Samantha G; Colantonio, Lisandro D; Gutiérrez, Orlando M; Shimbo, Daichi; Reynolds, Kristi; Wright, Nicole C; Curtis, Jeffrey R; Judd, Suzanne E; Franch, Harold; Warnock, David G; McClellan, William; Muntner, Paul
2016-07-07
Falls are common and associated with adverse outcomes in patients on dialysis. Limited data are available in earlier stages of CKD. We analyzed data from 8744 Reasons for Geographic and Racial Differences in Stroke Study participants ≥65 years old with Medicare fee for service coverage. Serious fall injuries were defined as a fall-related fracture, brain injury, or joint dislocation using Medicare claims. Hazard ratios (HRs) for serious fall injuries were calculated by eGFR and albumin-to-creatinine ratio (ACR). Among 2590 participants with CKD (eGFRfall injury compared with age-matched controls without a fall injury was calculated. Overall, 1103 (12.6%) participants had a serious fall injury over 9.9 years of follow-up. The incidence rates per 1000 person-years of serious fall injuries were 21.7 (95% confidence interval [95% CI], 20.3 to 23.2), 26.6 (95% CI, 22.6 to 31.3), and 38.3 (95% CI, 31.2 to 47.0) at eGFR levels ≥60, 45-59, and fall injuries were 0.91 (95% CI, 0.76 to 1.09) and 1.09 (95% CI, 0.86 to 1.37) for eGFR=45-59 and fall and age-matched controls were 21.0% and 5.5%, respectively. Elevated ACR but not lower eGFR was associated with serious fall injuries. Evaluation for fall risk factors and fall prevention strategies should be considered for older adults with elevated ACR. Copyright © 2016 by the American Society of Nephrology.
Association of eGFR-Related Loci Identified by GWAS with Incident CKD and ESRD.
Directory of Open Access Journals (Sweden)
Carsten A Böger
2011-09-01
Full Text Available Family studies suggest a genetic component to the etiology of chronic kidney disease (CKD and end stage renal disease (ESRD. Previously, we identified 16 loci for eGFR in genome-wide association studies, but the associations of these single nucleotide polymorphisms (SNPs for incident CKD or ESRD are unknown. We thus investigated the association of these loci with incident CKD in 26,308 individuals of European ancestry free of CKD at baseline drawn from eight population-based cohorts followed for a median of 7.2 years (including 2,122 incident CKD cases defined as eGFR <60ml/min/1.73m(2 at follow-up and with ESRD in four case-control studies in subjects of European ancestry (3,775 cases, 4,577 controls. SNPs at 11 of the 16 loci (UMOD, PRKAG2, ANXA9, DAB2, SHROOM3, DACH1, STC1, SLC34A1, ALMS1/NAT8, UBE2Q2, and GCKR were associated with incident CKD; p-values ranged from p = 4.1e-9 in UMOD to p = 0.03 in GCKR. After adjusting for baseline eGFR, six of these loci remained significantly associated with incident CKD (UMOD, PRKAG2, ANXA9, DAB2, DACH1, and STC1. SNPs in UMOD (OR = 0.92, p = 0.04 and GCKR (OR = 0.93, p = 0.03 were nominally associated with ESRD. In summary, the majority of eGFR-related loci are either associated or show a strong trend towards association with incident CKD, but have modest associations with ESRD in individuals of European descent. Additional work is required to characterize the association of genetic determinants of CKD and ESRD at different stages of disease progression.
International Nuclear Information System (INIS)
Kim, Gyoung Min; Lee, Hak Jong; Hwang, Sung Il; Chin, Ho Jun
2011-01-01
We wanted to determine the correlation between the renal length as measured on two dimensional (2D) ultrasonography (US) and the renal parenchymal volume as measured with a new three-dimensional (3D) volume probe ultrasound system. We also wanted to determine the correlation between the renal length or renal parenchymal volume and the glomerular filtration rate (GFR) in patients with glomerulopathy. From July 2007 to December 2007, 26 patients who were pathologically confirmed to have glomerulopathy by biopsy were enrolled. Renal length was measured with 2D US and the renal parenchymal volume was measured with 3D US just prior to biopsy. The GFR was obtained from the electronic medical records. Pearson's correlation coefficients were used to analyze the correlation between the renal length and the renal parenchymal volume, the correlation between the renal length and the GFR and the correlation between the renal parenchymal volume and the GFR. The renal length and the renal parenchymal volume showed strong positive correlation (r = 0.850, p = 0.0001). The correlation coefficient between the renal length and the GFR was 0.623 (p = 0.0007) and the correlation coefficient between the renal volume and the GFR was 0.590 (p = 0.0015). Both the renal length and renal parenchymal volume showed apparently positive correlations with the GFR in glomerulopathy patients. The renal length showed strong positive correlations with the renal parenchymal volume. Both the renal length and the renal parenchymal volume showed apparently positive correlations with the GFR in glomerulopathy patients. In glomerulopathy patients, the renal dimensions measured by ultrasound can reflect the status of the GFR, and the measurement of the 2D renal length could be sufficient for follow up. Further studies are needed to evaluate the role of 3D US for assessing patients with renal disease
Energy Technology Data Exchange (ETDEWEB)
You, Shan [Hebei North University, Department of Graduate, Zhangjiakou City, Hebei Province (China); Ma, XianWu; Zhang, ChangZhu; Li, Qiang [Qiqihar Chinese Medicine Hospital, Department of Radiology, Qigihar City, Heilongjiang Province (China); Shi, WenWei; Zhang, Jing; Yuan, XiaoDong [The 309th Hospital of Chinese People' s Liberation Army, Department of Radiology, Beijing (China)
2018-03-15
To present a single-kidney CT-GFR measurement and compare it with the renal dynamic imaging Gates-GFR. Thirty-six patients with hydronephrosis referred for CT urography and 99mTc-DTPA renal dynamic imaging were prospectively included. Informed consent was obtained from all patients. The CT urography protocol included non-contrast, nephrographic, and excretory phase imaging. The total CT-GFR was calculated by dividing the CT number increments of the total urinary system between the nephrographic and excretory phase by the products of iodine concentration in the aorta and the elapsed time, then multiplied by (1- Haematocrit). The total CT-GFR was then split into single-kidney CT-GFR by a left and right kidney proportionality factor. The results were compared with single-kidney Gates-GFR by using paired t-test, correlation analysis, and Bland-Altman plots. Paired difference between single-kidney CT-GFR (45.02 ± 13.91) and single-kidney Gates-GFR (51.21 ± 14.76) was 6.19 ± 5.63 ml/min, p<0.001, demonstrating 12.1% systematic underestimation with ±11.03 ml/min (±21.5%) measurement deviation. A good correlation was revealed between both measurements (r=0.87, p<0.001). The proposed single-kidney CT-GFR correlates and agrees well with the reference standard despite a systematic underestimation, therefore it could be a one-stop-shop for evaluating urinary tract morphology and split renal function. (orig.)
International Nuclear Information System (INIS)
Chi Xiaohua; Li Guiping; Liu Feng; Wang Bing; Du Li; Deng Zhifang; Li Wei
2013-01-01
Background: Diabetes nephropathy is a common complication of diabetes mellitus patients. Early detection of renal impairment can improve the quality of life of patients. Purpose: The value of total GFR, serum creatinine, 24-hour urine protein excretion in diabetes mellitus patients with renal impairment were evaluated. Methods: A retrospective analysis of 147 patients with diabetes undergoing routine renal dynamic imaging was undertaken. The cases were divided into three groups according to the illness duration: group I of not more than five years, group 2 of five to ten years, Gr.3: more than ten years. The 22 renal transplant donors were selected as the normal control group, The total GFR, serum creatinine and 24-hour urinary protein excretion of all patients were measured before the treatments, and the data were statistically analyzed. Results: There was no significant differences in renal function between the two kidneys of in the diabetes mellitus patients (P=0.536). Serum creatinine and total GFR had significant correlation (R 2 =0.762), but no significant relationship between the 24-hour urine protein and the total GFR or serum creatinine. In the early and middle times of renal function impairment, the total GFR and serum creatinine have significant difference in different time periods (P<0.05). During the mid-late times of renal function impairment, total GFR and serum creatinine have no statistically significant differences (P value is 0.781, 0.297). 24-hour urine protein quality had no statistical differences in each stage. However: the total GFR is more sensitive than the serum creatinine in evaluation of early impairing of renal function. Conclusions: There is significant correlation between serum creatinine and total GFR. Both of them can reflect the degree of diabetic renal injury, but the total GFR is more sensitive than serum creatinine in early degree. 24-hour urine protein quantitative can not evaluate the degree of impaired renal function alone
International Nuclear Information System (INIS)
You, Shan; Ma, XianWu; Zhang, ChangZhu; Li, Qiang; Shi, WenWei; Zhang, Jing; Yuan, XiaoDong
2018-01-01
To present a single-kidney CT-GFR measurement and compare it with the renal dynamic imaging Gates-GFR. Thirty-six patients with hydronephrosis referred for CT urography and 99mTc-DTPA renal dynamic imaging were prospectively included. Informed consent was obtained from all patients. The CT urography protocol included non-contrast, nephrographic, and excretory phase imaging. The total CT-GFR was calculated by dividing the CT number increments of the total urinary system between the nephrographic and excretory phase by the products of iodine concentration in the aorta and the elapsed time, then multiplied by (1- Haematocrit). The total CT-GFR was then split into single-kidney CT-GFR by a left and right kidney proportionality factor. The results were compared with single-kidney Gates-GFR by using paired t-test, correlation analysis, and Bland-Altman plots. Paired difference between single-kidney CT-GFR (45.02 ± 13.91) and single-kidney Gates-GFR (51.21 ± 14.76) was 6.19 ± 5.63 ml/min, p<0.001, demonstrating 12.1% systematic underestimation with ±11.03 ml/min (±21.5%) measurement deviation. A good correlation was revealed between both measurements (r=0.87, p<0.001). The proposed single-kidney CT-GFR correlates and agrees well with the reference standard despite a systematic underestimation, therefore it could be a one-stop-shop for evaluating urinary tract morphology and split renal function. (orig.)
Development of multi-group xs libraries for the gfr 2400 reactor
International Nuclear Information System (INIS)
Cerba, Š.; Vrban, B.; Lüley, J.; Necas, V.
2016-01-01
GFR 2400 is considered as a conceptual design of the large scale GEN IV Gas-Cooled Fast Reactor. In general, the GEN IV technologies are seen as reliable but also very challenging reactor concepts. Since GFR 2400 lacks any experimental data, the questions on its safety are even more complex and the assessment of its performance could be made only based on computational experience. The paper deals with the development process of multi-group XS libraries based on a hybrid deterministic-Stochastic methodology, using the NJOY99, TRANSX, DIF3D, PARTISN and MCNP5 codes. A new optimized 25 group SBJ E 71 2 5G cross section library was developed based on ENDF/B-VII.1 evaluated data, ZZ-KAFAX-E70 background cross sections and GFR 2400 neutron spectrum. The created library was validated through integral experiments evaluated on the HEX-Z deterministic models in DIF3D. The results were also compared with MCNP5 calculations. (authors)
Prediction of hospital mortality by changes in the estimated glomerular filtration rate (eGFR).
LENUS (Irish Health Repository)
Berzan, E
2015-03-01
Deterioration of physiological or laboratory variables may provide important prognostic information. We have studied whether a change in estimated glomerular filtration rate (eGFR) value calculated using the (Modification of Diet in Renal Disease (MDRD) formula) over the hospital admission, would have predictive value. An analysis was performed on all emergency medical hospital episodes (N = 61964) admitted between 1 January 2002 and 31 December 2011. A stepwise logistic regression model examined the relationship between mortality and change in renal function from admission to discharge. The fully adjusted Odds Ratios (OR) for 5 classes of GFR deterioration showed a stepwise increased risk of 30-day death with OR\\'s of 1.42 (95% CI: 1.20, 1.68), 1.59 (1.27, 1.99), 2.71 (2.24, 3.27), 5.56 (4.54, 6.81) and 11.9 (9.0, 15.6) respectively. The change in eGFR during a clinical episode, following an emergency medical admission, powerfully predicts the outcome.
Analysis of a convection loop for GFR post-LOCA decay heat removal
International Nuclear Information System (INIS)
Williams, W.C.; Hejzlar, P.; Saha, P.
2004-01-01
A computer code (LOCA-COLA) has been developed at MIT for steady state analysis of convective heat transfer loops. In this work, it is used to investigate an external convection loop for decay heat removal of a post-LOCA gas-cooled fast reactor (GFR). The major finding is that natural circulation cooling of the GFR is feasible under certain circumstances. Both helium and CO 2 cooled system components are found to operate in the mixed convection regime, the effects of which are noticeable as heat transfer enhancement or degradation. It is found that CO 2 outdoes helium under identical natural circulation conditions. Decay heat removal is found to have a quadratic dependence on pressure in the laminar flow regime and linear dependence in the turbulent flow regime. Other parametric studies have been performed as well. In conclusion, convection cooling loops are a credible means for GFR decay heat removal and LOCA-COLA is an effective tool for steady state analysis of cooling loops. (authors)
Equilibrium Droplets on Deformable Substrates: Equilibrium Conditions.
Koursari, Nektaria; Ahmed, Gulraiz; Starov, Victor M
2018-05-15
Equilibrium conditions of droplets on deformable substrates are investigated, and it is proven using Jacobi's sufficient condition that the obtained solutions really provide equilibrium profiles of both the droplet and the deformed support. At the equilibrium, the excess free energy of the system should have a minimum value, which means that both necessary and sufficient conditions of the minimum should be fulfilled. Only in this case, the obtained profiles provide the minimum of the excess free energy. The necessary condition of the equilibrium means that the first variation of the excess free energy should vanish, and the second variation should be positive. Unfortunately, the mentioned two conditions are not the proof that the obtained profiles correspond to the minimum of the excess free energy and they could not be. It is necessary to check whether the sufficient condition of the equilibrium (Jacobi's condition) is satisfied. To the best of our knowledge Jacobi's condition has never been verified for any already published equilibrium profiles of both the droplet and the deformable substrate. A simple model of the equilibrium droplet on the deformable substrate is considered, and it is shown that the deduced profiles of the equilibrium droplet and deformable substrate satisfy the Jacobi's condition, that is, really provide the minimum to the excess free energy of the system. To simplify calculations, a simplified linear disjoining/conjoining pressure isotherm is adopted for the calculations. It is shown that both necessary and sufficient conditions for equilibrium are satisfied. For the first time, validity of the Jacobi's condition is verified. The latter proves that the developed model really provides (i) the minimum of the excess free energy of the system droplet/deformable substrate and (ii) equilibrium profiles of both the droplet and the deformable substrate.
Snanoudj, R; Rabant, M; Timsit, M O; Karras, A; Savoye, E; Tricot, L; Loupy, A; Hiesse, C; Zuber, J; Kreis, H; Martinez, F; Thervet, E; Méjean, A; Lebret, T; Legendre, C; Delahousse, M
2009-11-01
It has been suggested that dual kidney transplantation (DKT) improves outcomes for expanded criteria donor (ECD) kidneys. However, no criteria for allocation to single or dual transplantation have been assessed prospectively. The strategy of DKT remains underused and potentially eligible kidneys are frequently discarded. We prospectively compared 81 DKT and 70 single kidney transplant (SKT) receiving grafts from ECD donors aged >65 years, allocated according to donor estimated glomerular filtration rate (eGFR): DKT if eGFR between 30 and 60 mL/min, SKT if eGFR greater than 60 mL/min. Patient and graft survival were similar in the two groups. In the DKT group, 13/81 patients lost one of their two kidneys due to hemorrhage, arterial or venous thrombosis. Mean eGFR at month 12 was similar in the DKT and SKT groups (47.8 mL/min and 46.4 mL/min, respectively). Simulated allocation of kidneys according to criteria based on day 0 donor parameters such as those described by Remuzzi et al., Andres et al. and UNOS, did not indicate an improvement in 12-month eGFR compared to our allocation based on donor eGFR.
Nishimura, Takeshi; Tanaka, Masami; Sekioka, Risa; Itoh, Hiroshi
2015-01-01
Although relationships of serum bilirubin concentration with estimated glomerular filtration rate (eGFR) and urinary albumin excretion (UAE) in patients with type 2 diabetes have been reported, whether such relationships exist in patients with type 1 diabetes is unknown. A total of 123 patients with type 1 diabetes were investigated in this cross-sectional study. The relationship between bilirubin (total and indirect) concentrations and log(UAE) as well as eGFR was examined by Pearson's correlation analyses. Multivariate regression analyses were used to assess the association of bilirubin (total and indirect) with eGFR as well as log(UAE). A positive correlation was found between serum bilirubin concentration and eGFR; total bilirubin (r=0.223, p=0.013), indirect bilirubin (r=0.244, p=0.007). A negative correlation was found between serum bilirubin concentration and log(UAE); total bilirubin (r=-0.258, p=0.005), indirect bilirubin (r=-0.271, p=0.003). Multivariate regression analyses showed that indirect bilirubin concentration was an independent determinant of eGFR and log(UAE). Bilirubin concentration is associated with both eGFR and log(UAE) in patients with type 1 diabetes. Bilirubin might have a protective role in the progression of type 1 diabetic nephropathy. Copyright © 2015 Elsevier Inc. All rights reserved.
Estimating GFR in children with 99mTc-DTPA renography
DEFF Research Database (Denmark)
Gutte, Henrik; Møller, Michael L; Pfeifer, Andreas K
2010-01-01
study was to evaluate the accuracy of this non-invasive method in children. We calculated GFR from (99m)Tc-diethylene triamine pentaacetic acid (DTPA) renography and compared with (51)Cr-EDTA plasma clearance of 29 children between the age of 1 month and 12 years (mean 4.7 years). The correlation...... between (99m)Tc-DTPA renography and (51)Cr-EDTA plasma clearance was for all children R = 0.96 (n = 29, PTc-DTPA renography is reliable...
Ion exchange equilibrium constants
Marcus, Y
2013-01-01
Ion Exchange Equilibrium Constants focuses on the test-compilation of equilibrium constants for ion exchange reactions. The book first underscores the scope of the compilation, equilibrium constants, symbols used, and arrangement of the table. The manuscript then presents the table of equilibrium constants, including polystyrene sulfonate cation exchanger, polyacrylate cation exchanger, polymethacrylate cation exchanger, polysterene phosphate cation exchanger, and zirconium phosphate cation exchanger. The text highlights zirconium oxide anion exchanger, zeolite type 13Y cation exchanger, and
Quantity Constrained General Equilibrium
Babenko, R.; Talman, A.J.J.
2006-01-01
In a standard general equilibrium model it is assumed that there are no price restrictions and that prices adjust infinitely fast to their equilibrium values.In case of price restrictions a general equilibrium may not exist and rationing on net demands or supplies is needed to clear the markets.In
Directory of Open Access Journals (Sweden)
I Gede Krisnayoga Kusuma
2017-08-01
Full Text Available Disruption of the distribution system is generally caused by a short circuit that causes overcurrent, one single phase short circuit to ground. Single phase to ground disturbances that occurred at the feeder should be secured by a ground fault relays in feeders. However, due to an error of coordination, interference with the feeder perceived also to the incoming side of the transformer so that ground fault relays on the incoming 20 kV ordered PMT 20 kV at the transformer side open. Working time ground fault relays in feeders Peguyangan is for 0.25 seconds. While working time ground fault relays in the incoming 20 kV is for 0.5 seconds. This indicates that differences in work time relay by 0.25 seconds is considered selective. The event of disruption of the ground phase, GFR relay coordination in securing the area of ??interference must be gradual. Where the value of working time ground fault relays in the base should be longer than the time ground fault relays working on a feeder. It aims to work ground fault relays working order, so that errors can be avoided in the security and do not lead to the spread of disturbed areas.
Saerom Yoon; Sungyeol Choi; Wonil Ko
2017-01-01
The focus on the issues surrounding spent nuclear fuel and lifetime extension of old nuclear power plants continues to grow nowadays. A transparent decision-making process to identify the best suitable nuclear fuel cycle (NFC) is considered to be the key task in the current situation. Through this study, an attempt is made to develop an equilibrium model for the NFC to calculate the material flows based on 1 TWh of electricity production, and to perform integrated multicriteria decision-makin...
DEFF Research Database (Denmark)
Andersen, Trine Borup; Jødal, Lars; Bøgsted, Martin
) aged 2-14 years (mean 8.8 years). GFR was 14-147 mL/min/1.73m2 (mean 97 mL/min/1.73m2). BCM was estimated using bioimpedance spectroscopy (Xitron Hydra 4200). Log-transformed data on BCM/CysC, serum creatinine (SCr), body-surface-area (BSA), height x BSA/SCr, serum CysC, weight, sex, age, height, serum....... The present equation also had the highest R2 and the narrowest 95% limits of agreement. CONCLUSION: The new equation predicts GFR with higher accuracy than other equations. Endogenous methods are, however, still not accurate enough to replace exogenous markers when GFR must be determined with high accuracy...
DEFF Research Database (Denmark)
Andersen, Trine Borup; Jødal, Lars; Bøgsted, Martin
) aged 2-14 years (mean 8.8 years). GFR was 14-147 mL/min/1.73m2 (mean 97 mL/min/1.73m2). BCM was estimated using bioimpedance spectroscopy (Xitron Hydra 4200). Log-transformed data on BCM/CysC, serum creatinine (SCr), body-surface-area (BSA), height x BSA/SCr, serum CysC, weight, sex, age, height, serum....... The present equation also had the highest R2 and the narrowest 95% limits of agreement. CONCLUSION: The new equation predicts GFR with higher accuracy than other equations. Endogenous methods are, however, still not accurate enough to replace exogenous markers when GFR must be determined with high accuracy...
Brignole, Esteban Alberto
2013-01-01
Traditionally, the teaching of phase equilibria emphasizes the relationships between the thermodynamic variables of each phase in equilibrium rather than its engineering applications. This book changes the focus from the use of thermodynamics relationships to compute phase equilibria to the design and control of the phase conditions that a process needs. Phase Equilibrium Engineering presents a systematic study and application of phase equilibrium tools to the development of chemical processes. The thermodynamic modeling of mixtures for process development, synthesis, simulation, design and
International Nuclear Information System (INIS)
Balter, H.S.
1994-01-01
This work studies the behaviour of radionuclides when it produce a desintegration activity,decay and the isotopes stable creation. It gives definitions about the equilibrium between activity of parent and activity of the daughter, radioactive decay,isotope stable and transient equilibrium and maxim activity time. Some considerations had been given to generators that permit a disgregation of two radioisotopes in equilibrium and its good performance. Tabs
Synthesis of the safety studies carried out on the GFR2400
Energy Technology Data Exchange (ETDEWEB)
Bertrand, F., E-mail: frederic.bertrand@cea.fr [CEA, DEN, DER, F-13108, Saint Paul-lez-Durance (France); Bassi, C. [CEA, DEN, DER, F-13108, Saint Paul-lez-Durance (France); Bentivoglio, F. [CEA, DEN, DM2S, F-38054, Grenoble (France); Audubert, F. [CEA, DEN, DEC, F-13108, Saint Paul-lez-Durance (France); Gueneau, C. [CEA, DEN, DPC, F-91191, Gif-sur-yvette (France); Rimpault, G. [CEA, DEN, DER, F-13108, Saint Paul-lez-Durance (France); Journeau, C. [CEA, DEN, DTN, F-13108, Saint Paul-lez-Durance (France)
2012-12-15
Highlights: Black-Right-Pointing-Pointer Insights from accident studies and PSA have consolidated GFR2400 design. Black-Right-Pointing-Pointer Safety margins are adequate for design basis accidents. Black-Right-Pointing-Pointer Core cooling strategy is reinforced by use of PCS for frequent events. Black-Right-Pointing-Pointer Prevention of core degradation is shown in challenging hypothetic situations. Black-Right-Pointing-Pointer It is shown that most of severe accidents can be managed despite limited test data. - Abstract: The present paper is dedicated to the synthesis of the safety studies carried out on the 2400 MWth gas-cooled fast reactor (GFR2400) concept developed at CEA. The analysis of the reference design basis accidents investigated up to now, has shown margins up to the acceptance criteria, equal at least to 300 Degree-Sign C for the category 3 situations and larger than 100 Degree-Sign C for the category 4 situations. The dimensioning of the decay heat removal (DHR) loops and of the power conversion system (PCS) loops has been shown adequate even for bounding degraded situations including multiple failures. Furthermore, in the following part of the paper, it is shown how the main insights provided by a level 1 probabilistic safety assessment (PSA) carried out at an early stage of the design, have led to reinforce the reliability of the DHR function in high pressure conditions by using the PCS as the first mean to cool the core; in the same time, on the basis of a combination of deterministic augments and of PSA results, a design simplification process has led to add a low pressure DHR loop to replace a high pressure DHR loop. The last section is dedicated to prevention and preliminary study of severe accidents (SA). Four SA families have been identified depending on the dynamics and on the scale of the considered accident. The possibility to prevent core degradation by using an adapted accident management (nitrogen injection, use of PCS loops) has
DEFF Research Database (Denmark)
Sibilitz, Kirstine L; Benn, Marianne; Nordestgaard, Børge G
2014-01-01
OBJECTIVE: We tested the hypothesis that moderately elevated plasma creatinine levels and decreased levels of estimated glomerular filtration rate (eGFR) are associated with increased risk of myocardial infarction, ischemic heart disease, and early death in the general population. METHODS: We...... studied 10,489 individuals with a plasma creatinine measurement and calculated eGFR from the Danish general population, of which 1498 developed myocardial infarction, 3001 ischemic heart disease, and 7573 died during 32 years follow-up. RESULTS: Cumulative incidences of myocardial infarction and ischemic...... heart disease as a function of age increased with increasing levels of creatinine, and survival decreased (log-rank trends: creatinine levels
Kleppe, J.; Borm, P.E.M.; Hendrickx, R.L.P.
2008-01-01
Fall back equilibrium is a refinement of the Nash equilibrium concept. In the underly- ing thought experiment each player faces the possibility that, after all players decided on their action, his chosen action turns out to be blocked. Therefore, each player has to decide beforehand on a back-up
Risk premia in general equilibrium
DEFF Research Database (Denmark)
Posch, Olaf
This paper shows that non-linearities can generate time-varying and asymmetric risk premia over the business cycle. These (empirical) key features become relevant and asset market implications improve substantially when we allow for non-normalities in the form of rare disasters. We employ explici......'s effective risk aversion.......This paper shows that non-linearities can generate time-varying and asymmetric risk premia over the business cycle. These (empirical) key features become relevant and asset market implications improve substantially when we allow for non-normalities in the form of rare disasters. We employ explicit...... solutions of dynamic stochastic general equilibrium models, including a novel solution with endogenous labor supply, to obtain closed-form expressions for the risk premium in production economies. We find that the curvature of the policy functions affects the risk premium through controlling the individual...
James, Matthew T.; Grams, Morgan E.; Woodward, Mark; Elley, C. Raina; Green, Jamie A.; Wheeler, David C.; de Jong, Paul; Gansevoort, Ron T.; Levey, Andrew S.; Warnock, David G.; Sarnak, Mark J.; de Zeeuw, Dick; Bakker, Stephan J. L.; van der Harst, Pim; Heerspink, Hiddo J.
2015-01-01
Background: Diabetes mellitus and hypertension are risk factors for acute kidney injury (AKI). Whether estimated glomerular filtration rate (eGFR) and urine albumin-creatinine ratio (ACR) remain risk factors for AKI in the presence and absence of these conditions is uncertain. Study Design:
DEFF Research Database (Denmark)
Andersen, Trine Borup; Jødal, Lars; Bøgsted, Martin
using robust regression in a forward, stepwise procedure. GFR (mL/min) was the dependent variable. The accuracy and precision of the prediction model were compared to other prediction models from the literature, using k-fold cross-validation. Local constants and coefficients were calculated for all...
Lin, Jin-Ding; Lin, Lan-Ping; Hsieh, Molly; Lin, Pei-Ying
2010-01-01
The present study aimed to describe the kidney function profile--serum creatinine and estimated glomerular filtration rate (eGFR), and to examine the relationships of predisposing factors to abnormal serum creatinine in people with intellectual disabilities (ID). Data were collected by a cross-sectional study of 827 aged 15-18 years adolescents…
Equilibrium and non equilibrium in fragmentation
International Nuclear Information System (INIS)
Dorso, C.O.; Chernomoretz, A.; Lopez, J.A.
2001-01-01
Full text: In this communication we present recent results regarding the interplay of equilibrium and non equilibrium in the process of fragmentation of excited finite Lennard Jones drops. Because the general features of such a potential resemble the ones of the nuclear interaction (fact that is reinforced by the similarity between the EOS of both systems) these studies are not only relevant from a fundamental point of view but also shed light on the problem of nuclear multifragmentation. We focus on the microscopic analysis of the state of the fragmenting system at fragmentation time. We show that the Caloric Curve (i e. the functional relationship between the temperature of the system and the excitation energy) is of the type rise plateau with no vapor branch. The usual rise plateau rise pattern is only recovered when equilibrium is artificially imposed. This result puts a serious question on the validity of the freeze out hypothesis. This feature is independent of the dimensionality or excitation mechanism. Moreover we explore the behavior of magnitudes which can help us determine the degree of the assumed phase transition. It is found that no clear cut criteria is presently available. (Author)
Non-Equilibrium Thermodynamics of Self-Replicating Protocells
DEFF Research Database (Denmark)
Fellermann, Harold; Corominas-Murtra, Bernat; Hansen, Per Lyngs
2018-01-01
We provide a non-equilibrium thermodynamic description of the life-cycle of a droplet based, chemically feasible, system of protocells. By coupling the protocells metabolic kinetics with its thermodynamics, we demonstrate how the system can be driven out of equilibrium to ensure protocell growth...... and replication. This coupling allows us to derive the equations of evolution and to rigorously demonstrate how growth and replication life-cycle can be understood as a non-equilibrium thermodynamic cycle. The process does not appeal to genetic information or inheritance, and is based only on non......-equilibrium physics considerations. Our non-equilibrium thermodynamic description of simple, yet realistic, processes of protocell growth and replication, represents an advance in our physical understanding of a central biological phenomenon both in connection to the origin of life and for modern biology....
Singh, Prempal; Bansal, Ankur; Sekhon, Virender; Nunia, Sandeep; Ansari, M S
2018-01-01
To assess cut-off value of creatinine and glomerular filtration rate for augmentation cystoplasty (AC) in paediatric age-group. Data of all paediatric-patients (Creatinine and e-GFR were assessed at the time of surgery, at 6 months and at last follow-up. Renal function deterioration was defined as increase in creatinine by ≥25% from baseline value or new-onset stage-3 CKD or worsening of CKD stage with pre-operative-CKD stage-3. ROCs were plotted using creatinine and e-GFR for AC. A total of 94 patients with mean-age 8.9 years were included. The mean creatinine and e-GFR were 1.33mg/dL and 57.68mL/min respectively. Out of 94 patients, AC was performed in 45 patients and in the remaining 49 patients AC was not done (control-group), as they were not willing for the same. Baseline patient's characteristics were comparable in both Groups. 22 underwent gastro-cystoplasty (GC) and 25 underwent ileo-cystoplasty (IC). Decline in renal function was observed in 15 (33.3%) patients of AC-group and in 31 (63.3%) patients of control-group. Patients having creatinine ≥1.54mg/dL (P=0.004, sensitivity (S) 63.6% and specificity (s) 90.5%) at baseline and e-GFR ≤46mL/min (P=0.000, S=100% and s=85.7%) at the time of surgery had significantly increased probability of renal function deterioration on follow-up after AC. e-GFR ≤46mL/min and creatinine ≥1.54mg/dL at time of surgery could serve as a predictor of renal function deterioration in AC in paediatric patients. Copyright® by the International Brazilian Journal of Urology.
Directory of Open Access Journals (Sweden)
Kevin V Lemley
Full Text Available Most predictive models of kidney disease progression have not incorporated structural data. If structural variables have been used in models, they have generally been only semi-quantitative.We examined the predictive utility of quantitative structural parameters measured on the digital images of baseline kidney biopsies from the NEPTUNE study of primary proteinuric glomerulopathies. These variables were included in longitudinal statistical models predicting the change in estimated glomerular filtration rate (eGFR over up to 55 months of follow-up.The participants were fifty-six pediatric and adult subjects from the NEPTUNE longitudinal cohort study who had measurements made on their digital biopsy images; 25% were African-American, 70% were male and 39% were children; 25 had focal segmental glomerular sclerosis, 19 had minimal change disease, and 12 had membranous nephropathy. We considered four different sets of candidate predictors, each including four quantitative structural variables (for example, mean glomerular tuft area, cortical density of patent glomeruli and two of the principal components from the correlation matrix of six fractional cortical areas-interstitium, atrophic tubule, intact tubule, blood vessel, sclerotic glomerulus, and patent glomerulus along with 13 potentially confounding demographic and clinical variables (such as race, age, diagnosis, and baseline eGFR, quantitative proteinuria and BMI. We used longitudinal linear models based on these 17 variables to predict the change in eGFR over up to 55 months. All 4 models had a leave-one-out cross-validated R2 of about 62%.Several combinations of quantitative structural variables were significantly and strongly associated with changes in eGFR. The structural variables were generally stronger than any of the confounding variables, other than baseline eGFR. Our findings suggest that quantitative assessment of diagnostic renal biopsies may play a role in estimating the baseline
Chemical Principles Revisited: Chemical Equilibrium.
Mickey, Charles D.
1980-01-01
Describes: (1) Law of Mass Action; (2) equilibrium constant and ideal behavior; (3) general form of the equilibrium constant; (4) forward and reverse reactions; (5) factors influencing equilibrium; (6) Le Chatelier's principle; (7) effects of temperature, changing concentration, and pressure on equilibrium; and (8) catalysts and equilibrium. (JN)
Equilibrium and non-equilibrium phenomena in arcs and torches
Mullen, van der J.J.A.M.
2000-01-01
A general treatment of non-equilibrium plasma aspects is obtained by relating transport fluxes to equilibrium restoring processes in so-called disturbed Bilateral Relations. The (non) equilibrium stage of a small microwave induced plasma serves as case study.
Directory of Open Access Journals (Sweden)
Katalin Martinás
2007-02-01
Full Text Available A microeconomic, agent based framework to dynamic economics is formulated in a materialist approach. An axiomatic foundation of a non-equilibrium microeconomics is outlined. Economic activity is modelled as transformation and transport of commodities (materials owned by the agents. Rate of transformations (production intensity, and the rate of transport (trade are defined by the agents. Economic decision rules are derived from the observed economic behaviour. The non-linear equations are solved numerically for a model economy. Numerical solutions for simple model economies suggest that the some of the results of general equilibrium economics are consequences only of the equilibrium hypothesis. We show that perfect competition of selfish agents does not guarantee the stability of economic equilibrium, but cooperativity is needed, too.
Caplin, Ben; Jakobsson, Kristina; Glaser, Jason; Nitsch, Dorothea; Jha, Vivekanand; Singh, Ajay; Correa-Rotter, Ricardo; Pearce, Neil
2017-01-03
There is an increasing recognition of epidemics of primarily tubular-interstitial chronic kidney disease (CKD) clustering in agricultural communities in low- and middle-income countries (LMICs). Although it is currently unclear whether there is a unified underlying aetiology, these conditions have been collectively termed CKD of undetermined cause (CKDu). CKDu is estimated to have led to the premature deaths of tens to hundreds of thousands of young men and women over the last 2 decades. Thus, there is an urgent need to understand the aetiology and pathophysiology of these condition (s). International comparisons have provided the first steps in understanding many chronic diseases, but such comparisons rely on the availability of standardised tools to estimate disease prevalence. This is a particular problem with CKD, since the disease is asymptomatic until the late stages, and the biases inherent in the methods used to estimate the glomerular filtration rate (GFR) in population studies are highly variable across populations. We therefore propose a simple standardised protocol to estimate the distribution of GFR in LMIC populations - The Disadvantaged Populations eGFR Epidemiology (DEGREE) Study. This involves the quantification of renal function in a representative adult population-based sample and a requirement for standardisation of serum creatinine measurements, along with storage of samples for future measurements of cystatin C and ascertainment of estimates of body composition, in order to obtain valid comparisons of estimated GFR (eGFR) within and between populations. The methodology we present is potentially applicable anywhere, but our particular focus is on disadvantaged populations in LMICs, since these appear to be most susceptible to CKDu. Although the protocol could also be used in specific groups (e.g. occupational groups, thought to be at excess risk of CKDu) the primary aim of the DEGREE project is characterise the population distribution of eGFR
Equilibrium statistical mechanics
Mayer, J E
1968-01-01
The International Encyclopedia of Physical Chemistry and Chemical Physics, Volume 1: Equilibrium Statistical Mechanics covers the fundamental principles and the development of theoretical aspects of equilibrium statistical mechanics. Statistical mechanical is the study of the connection between the macroscopic behavior of bulk matter and the microscopic properties of its constituent atoms and molecules. This book contains eight chapters, and begins with a presentation of the master equation used for the calculation of the fundamental thermodynamic functions. The succeeding chapters highlight t
Computing Equilibrium Chemical Compositions
Mcbride, Bonnie J.; Gordon, Sanford
1995-01-01
Chemical Equilibrium With Transport Properties, 1993 (CET93) computer program provides data on chemical-equilibrium compositions. Aids calculation of thermodynamic properties of chemical systems. Information essential in design and analysis of such equipment as compressors, turbines, nozzles, engines, shock tubes, heat exchangers, and chemical-processing equipment. CET93/PC is version of CET93 specifically designed to run within 640K memory limit of MS-DOS operating system. CET93/PC written in FORTRAN.
Xenon thermal behavior in sintered titanium nitride, foreseen inert matrix for GFR
International Nuclear Information System (INIS)
Bes, R.
2010-11-01
This work concerns the generation IV future nuclear reactors such as gas-cooled fast reactor (GFR) for which refractory materials as titanium nitride (TiN) are needed to surround fuel and act as a fission product diffusion barrier. This study is about Xe thermal behavior in sintered titanium nitride. Microstructure effects on Xe behavior have been studied. In this purpose, several syntheses have been performed using different sintering temperatures and initial powder compositions. Xenon species have been introduced into samples by ionic implantation. Then, samples were annealed in temperature range from 1300 C to 1600 C, these temperatures being the accidental awaited temperature. A transport of xenon towards sample surface has been observed. Transport rate seems to be slow down when increasing sintering temperature. The composition of initial powder and the crystallographic orientation of each considered grain also influence xenon thermal behavior. Xenon release has been correlated with material oxidation during annealing. Xenon bubbles were observed. Their size is proportional with xenon concentration and increases with annealing temperature. Several mechanisms which could explain Xe intragranular mobility in TiN are proposed. In addition with experiments, very low Xe solubility in TiN has been confirmed by ab initio calculations. So, bi-vacancies were found to be the most favoured Xe incorporation sites in this material. (author)
Energy Technology Data Exchange (ETDEWEB)
Yoon, Sae Rom [Dept of Quantum Energy Chemical Engineering, Korea University of Science and Technology (KUST), Daejeon (Korea, Republic of); Choi, Sung Yeol [Ulsan National Institute of Science and Technology, Ulju (Korea, Republic of); Ko, Wonil [Nonproliferation System Development Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2017-02-15
The focus on the issues surrounding spent nuclear fuel and lifetime extension of old nuclear power plants continues to grow nowadays. A transparent decision-making process to identify the best suitable nuclear fuel cycle (NFC) is considered to be the key task in the current situation. Through this study, an attempt is made to develop an equilibrium model for the NFC to calculate the material flows based on 1 TWh of electricity production, and to perform integrated multicriteria decision-making method analyses via the analytic hierarchy process technique for order of preference by similarity to ideal solution, preference ranking organization method for enrichment evaluation, and multiattribute utility theory methods. This comparative study is aimed at screening and ranking the three selected NFC options against five aspects: sustainability, environmental friendliness, economics, proliferation resistance, and technical feasibility. The selected fuel cycle options include pressurized water reactor (PWR) once-through cycle, PWR mixed oxide cycle, or pyroprocessing sodium-cooled fast reactor cycle. A sensitivity analysis was performed to prove the robustness of the results and explore the influence of criteria on the obtained ranking. As a result of the comparative analysis, the pyroprocessing sodium-cooled fast reactor cycle is determined to be the most competitive option among the NFC scenarios.
International Nuclear Information System (INIS)
Yoon, Sae Rom; Choi, Sung Yeol; Ko, Wonil
2017-01-01
The focus on the issues surrounding spent nuclear fuel and lifetime extension of old nuclear power plants continues to grow nowadays. A transparent decision-making process to identify the best suitable nuclear fuel cycle (NFC) is considered to be the key task in the current situation. Through this study, an attempt is made to develop an equilibrium model for the NFC to calculate the material flows based on 1 TWh of electricity production, and to perform integrated multicriteria decision-making method analyses via the analytic hierarchy process technique for order of preference by similarity to ideal solution, preference ranking organization method for enrichment evaluation, and multiattribute utility theory methods. This comparative study is aimed at screening and ranking the three selected NFC options against five aspects: sustainability, environmental friendliness, economics, proliferation resistance, and technical feasibility. The selected fuel cycle options include pressurized water reactor (PWR) once-through cycle, PWR mixed oxide cycle, or pyroprocessing sodium-cooled fast reactor cycle. A sensitivity analysis was performed to prove the robustness of the results and explore the influence of criteria on the obtained ranking. As a result of the comparative analysis, the pyroprocessing sodium-cooled fast reactor cycle is determined to be the most competitive option among the NFC scenarios
Directory of Open Access Journals (Sweden)
Saerom Yoon
2017-02-01
Full Text Available The focus on the issues surrounding spent nuclear fuel and lifetime extension of old nuclear power plants continues to grow nowadays. A transparent decision-making process to identify the best suitable nuclear fuel cycle (NFC is considered to be the key task in the current situation. Through this study, an attempt is made to develop an equilibrium model for the NFC to calculate the material flows based on 1 TWh of electricity production, and to perform integrated multicriteria decision-making method analyses via the analytic hierarchy process technique for order of preference by similarity to ideal solution, preference ranking organization method for enrichment evaluation, and multiattribute utility theory methods. This comparative study is aimed at screening and ranking the three selected NFC options against five aspects: sustainability, environmental friendliness, economics, proliferation resistance, and technical feasibility. The selected fuel cycle options include pressurized water reactor (PWR once-through cycle, PWR mixed oxide cycle, or pyroprocessing sodium-cooled fast reactor cycle. A sensitivity analysis was performed to prove the robustness of the results and explore the influence of criteria on the obtained ranking. As a result of the comparative analysis, the pyroprocessing sodium-cooled fast reactor cycle is determined to be the most competitive option among the NFC scenarios.
Assessment of gas cooled fast reactor with indirect supercritical CO2 cycle
International Nuclear Information System (INIS)
Hejzlar, P.; Driscoll, M. J.; Dostal, V.; Dumaz, P.; Poullennec, G.; Alpy, N.
2006-01-01
Various indirect power cycle options for a helium cooled Gas cooled Fast Reactor (GFR) with particular focus on a supercritical CO 2 (SCO 2 ) indirect cycle are investigated as an alternative to a helium cooled direct cycle GFR. The Balance Of Plant (BOP) options include helium-nitrogen Brayton cycle, supercritical water Rankine cycle, and SCO 2 recompression Brayton power cycle in three versions: (1) basic design with turbine inlet temperature of 550 .deg. C, (2) advanced design with turbine inlet temperature of 650 .deg. C and (3) advanced design with the same turbine inlet temperature and reduced compressor inlet temperature. The indirect SCO 2 recompression cycle is found attractive since in addition to easier BOP maintenance it allows significant reduction of core outlet temperature, making design of the primary system easier while achieving very attractive efficiencies comparable to or slightly lower than, the efficiency of the reference GFR direct cycle design. In addition, the indirect cycle arrangement allows significant reduction of the GFR 'proximate-containment' and the BOP for the SCO 2 cycle is very compact. Both these factors will lead to reduced capital cost
High rates of albuminuria but not of low eGFR in Urban Indigenous Australians: the DRUID Study
Directory of Open Access Journals (Sweden)
Zimmet Paul Z
2011-05-01
Full Text Available Abstract Background Indigenous Australians have an incidence of end stage kidney disease 8-10 times higher than non-Indigenous Australians. The majority of research studies concerning Indigenous Australians have been performed in rural or remote regions, whilst the majority of Indigenous Australians actually live in urban settings. We studied prevalence and factors associated with markers of kidney disease in an urban Indigenous Australian cohort, and compared results with those for the general Australian population. Methods 860 Indigenous adult participants of the Darwin Region Urban Indigenous Diabetes (DRUID Study were assessed for albuminuria (urine albumin-creatinine ratio≥2.5 mg/mmol males, ≥3.5 mg/mmol females and low eGFR (estimated glomular filtration rate 2. Associations between risk factors and kidney disease markers were explored. Comparison was made with the AusDiab cohort (n = 8,936 aged 25-64 years, representative of the general Australian adult population. Results A high prevalence of albuminuria (14.8% was found in DRUID, whilst prevalence of low eGFR was 2.4%. Older age, higher HbA1c, hypertension, higher C-reactive protein and current smoking were independently associated with albuminuria on multiple regression. Low eGFR was independently associated with older age, hypertension, albuminuria and higher triglycerides. Compared to AusDiab participants, DRUID participants had a 3-fold higher adjusted risk of albuminuria but not of low eGFR. Conclusions Given the significant excess of ESKD observed in Indigenous versus non-Indigenous Australians, these findings could suggest either: albuminuria may be a better prognostic marker of kidney disease than low eGFR; that eGFR equations may be inaccurate in the Indigenous population; a less marked differential between Indigenous and non-Indigenous Australians for ESKD rates in urban compared to remote regions; or that differences in the pathophysiology of chronic kidney disease exist
Modification of a two blood sample method used for measurement of GFR with 99mTc-DTPA.
Surma, Marian J; Płachcińska, Anna; Kuśmierek, Jacek
2018-01-01
Measurements of GFR may be performed with a slope/intercept method (S/I), using only two blood samples taken in strictly defined time points. The aim of the study was to modify this method in order to extend time intervals suitable for blood sampling. Modification was based on a variation of a Russel et al. model parameter, selection of time intervals suitable for blood sampling and assessment of uncertainty of calculated results. Archived values of GFR measurements of 169 patients with different renal function, from 5.5 to 179 mL/min, calculated with a multiple blood sample method were used. Concentrations of a radiopharmaceutical in consecutive minutes, from 60th to 190th after injection, were calculated theoretically, using archived parameters of biexponential functions describing a decrease in 99mTc-DTPA concentration in blood plasma with time. These values, together with injected activities, were treated as measurements and used for S/I clearance calculations. Next, values of S/I clearance were compared with the multiple blood sample method in order to calculate suitable values of exponent present in a Russel's model, for every combination of two blood sampling time points. A model was considered accurately fitted to measured values when SEE ≤ 3.6 mL/min. Assessments of uncertainty of obtained results were based on law of error superposition, taking into account mean square prediction error and also errors introduced by pipetting, time measurement and stochastic radioactive decay. The accepted criteria resulted in extension of time intervals suitable for blood sampling to: between 60 and 90 minutes after injection for the first sample and between 150 and 180 minutes for the second sample. Uncertainty of results was assessed as between 4 mL/min for GFR = 5-10 mL/min and 8 mL/min for GFR = 180 mL/min. Time intervals accepted for blood sampling fully satisfy nuclear medicine staff and ensure proper determination of GFR. Uncertainty of results is entirely
Estimating renal function in children: a new GFR-model based on serum cystatin C and body cell mass.
Andersen, Trine Borup
2012-07-01
This PhD thesis is based on four individual studies including 131 children aged 2-14 years with nephro-urologic disorders. The majority (72%) of children had a normal renal function (GFR > 82 ml/min/1.73 square metres), and only 8% had a renal function thesis´ main aims were: 1) to develop a more accurate GFR model based on a novel theory of body cell mass (BCM) and cystatin C (CysC); 2) to investigate the diagnostic performance in comparison to other models as well as serum CysC and creatinine; 3) to validate the new models precision and validity. The model´s diagnostic performance was investigated in study I as the ability to detect changes in renal function (total day-to-day variation), and in study IV as the ability to discriminate between normal and reduced function. The model´s precision and validity were indirectly evaluated in study II and III, and in study I accuracy was estimated by comparison to reference GFR. Several prediction models based on CysC or a combination of CysC and serum creatinine have been developed for predicting GFR in children. Despite these efforts to improve GFR estimates, no alternative to exogenous methods has been found and the Schwartz´s formula based on height, creatinine and an empirically derived constant is still recommended for GFR estimation in children. However, the inclusion of BCM as a possible variable in a CysC-based prediction model has not yet been explored. As CysC is produced at a constant rate from all nucleated cells we hypothesize that including BCM in a new prediction model will increase accuracy of the GFR estimate. Study I aimed at deriving the new GFR-prediction model based on the novel theory of CysC and BCM and comparing the performance to previously published models. The BCM-model took the form GFR (mL/min) = 10.2 × (BCM/CysC)E 0.40 × (height × body surface area/Crea)E 0.65. The model predicted 99% within ± 30% of reference GFR, and 67% within ±10%. This was higher than any other model. The
Directory of Open Access Journals (Sweden)
I Dewa Gde Agung Budhi Udiana
2017-08-01
Full Text Available Short circuit causing over current problem and can might causing interference of the equipment performance such as distribution transformers also causing widespread disruption occurred. In resolving such interference is required as protection system on the distribution system. Seeing all above is needed coordination between the supporting component of the protection system which is consisted of Over Current Relay (OCR and Ground Fault Relay (GFR. The research was conducted at PT. PLN (Persero South Bali Area Network, INDONESIA on recloser in the feeder line of Penebel. OCR setting between the Relay feeder of Penebel, Recloser Celagi, Recloser Bakisan, and Recloser Benana still less selective, with time value coordination between average security was still less than 0,2 second. Then OCR setting and GFR relay feeder of Penebel, Recloser Celagi, Recloser Bakisan, and Recloser Benana was recommended for re-setting in order to minimize disruption and electric power distribution system to be reliable.
A GFR benchmark comparison of transient analysis codes based on the ETDR concept
International Nuclear Information System (INIS)
Bubelis, E.; Coddington, P.; Castelliti, D.; Dor, I.; Fouillet, C.; Geus, E. de; Marshall, T.D.; Van Rooijen, W.; Schikorr, M.; Stainsby, R.
2007-01-01
A GFR (Gas-cooled Fast Reactor) transient benchmark study was performed to investigate the ability of different code systems to calculate the transition in the core heat removal from the main circuit forced flow to natural circulation cooling using the Decay Heat Removal (DHR) system. This benchmark is based on a main blower failure in the Experimental Technology Demonstration Reactor (ETDR) with reactor scram. The codes taking part into the benchmark are: RELAP5, TRAC/AAA, CATHARE, SIM-ADS, MANTA and SPECTRA. For comparison purposes the benchmark was divided into several stages: the initial steady-state solution, the main blower flow run-down, the opening of the DHR loop and the transition to natural circulation and finally the 'quasi' steady heat removal from the core by the DHR system. The results submitted by the participants showed that all the codes gave consistent results for all four stages of the benchmark. In the steady-state the calculations revealed some differences in the clad and fuel temperatures, the core and main loop pressure drops and in the total Helium mass inventory. Also some disagreements were observed in the Helium and water flow rates in the DHR loop during the final natural circulation stage. Good agreement was observed for the total main blower flow rate and Helium temperature rise in the core, as well as for the Helium inlet temperature into the core. In order to understand the reason for the differences in the initial 'blind' calculations a second round of calculations was performed using a more precise set of boundary conditions
Inert materials for the GFR fuel. Characterizations, chemical interactions and irradiation damage
International Nuclear Information System (INIS)
Audubert, Fabienne; Carlot, Gaoelle; Lechelle, Jacques; David, Laurent; Gomes, Severine
2005-01-01
In the framework of an extensive R and D Program on GFR fuel, studies on inert materials have been performed at the French Atomic Energy Commission (CEA). The inert materials would be associated with the fuel with the aim of featuring an efficient barrier to radiotoxic species with regard to the cooling circuit of the reactor. Potential matrices identified for dispersion fuels or particles fuels are SiC, TiN, ZrN, ZrC, TiC. Physical microstructural and thermal properties have been determined in order to evaluate elaboration process effects. The evolution under irradiation of thermal properties (such as conductivity, diffusivity) of the materials has been studied using heavy ions to simulate fission product irradiation. After irradiation, scanning thermal microscopy is used to investigate the thermal degradation of the materials. Thermal conductivity variations were obtained on TiC irradiated with krypton ion at an energy of 86 MeV and a fluence of 5.10 15 ions.cm -2 . They are quantified at 19 W.m -1 .K -1 . On other materials such as SiC, ZrC, TiN, no thermal conductivity contrast was shown. Reactivity between the inert matrix (SiC or TiN) and the fuel (U, Pu)N have been evaluated on powders and on ceramic samples in contact by a thermal treatment under several atmospheres. It was shown that SiC reacts with (U, Pu)N in various atmospheres making secondary phases as PuSi 2 , USi 2 , U 20 Si 16 C 3 . TiN behaviour seems to be better: the only reactivity which may take place would be a variation of the nitrogen stoichiometry in TiN and (U, Pu)N at the interface. (author)
Sharma, Sheena; Denburg, Michelle R; Furth, Susan L
2017-08-01
Children with chronic kidney disease (CKD) have a high prevalence of cardiovascular disease (CVD) risk factors which may contribute to the development of cardiovascular events in adulthood. Among adults with CKD, cystatin C-based estimates of glomerular filtration rate (eGFR) demonstrate a stronger predictive value for cardiovascular events than creatinine-based eGFR. The PDAY (Pathobiological Determinants of Atherosclerosis in Youth) risk score is a validated tool used to estimate the probability of advanced coronary atherosclerotic lesions in young adults. To assess the association between cystatin C-based versus creatinine-based eGFR (eGFR cystatin C and eGFR creatinine, respectively) and cardiovascular risk using a modified PDAY risk score as a proxy for CVD in children and young adults. We performed a cross-sectional study of 71 participants with CKD [median age 15.5 years; inter-quartile range (IQR) 13, 17], and 33 healthy controls (median age 15.1 years; IQR 13, 17). eGFR was calculated using age-appropriate creatinine- and cystatin C-based formulas. Median eGFR creatinine and eGFR cystatin C for CKD participants were 50 (IQR 30, 75) and 53 (32, 74) mL/min/1.73 m 2 , respectively. For the healthy controls, median eGFR creatinine and eGFR cystatin were 112 (IQR 85, 128) and 106 mL/min/1.73m 2 (95, 123) mL/min/1.73 m 2 , respectively. A modified PDAY risk score was calculated based on sex, age, serum lipoprotein concentrations, obesity, smoking status, hypertension, and hyperglycemia. Modified PDAY scores ranged from -2 to 20. The Spearman's correlations of eGFR creatinine and eGFR cystatin C with coronary artery PDAY scores were -0.23 (p = 0.02) and -0.28 (p = 0.004), respectively. Ordinal logistic regression also showed a similar association of higher eGFR creatinine and higher eGFR cystatin C with lower PDAY scores. When stratified by age creatinine and eGFR cystatin C with PDAY score were modest and similar in children [-0.29 (p = 0.008) vs. -0.32 (p = 0
Eberl, Gérard
2016-08-01
The classical model of immunity posits that the immune system reacts to pathogens and injury and restores homeostasis. Indeed, a century of research has uncovered the means and mechanisms by which the immune system recognizes danger and regulates its own activity. However, this classical model does not fully explain complex phenomena, such as tolerance, allergy, the increased prevalence of inflammatory pathologies in industrialized nations and immunity to multiple infections. In this Essay, I propose a model of immunity that is based on equilibrium, in which the healthy immune system is always active and in a state of dynamic equilibrium between antagonistic types of response. This equilibrium is regulated both by the internal milieu and by the microbial environment. As a result, alteration of the internal milieu or microbial environment leads to immune disequilibrium, which determines tolerance, protective immunity and inflammatory pathology.
Pierce, Dwayne A; Russell, Greg; Pirkle, James L
2015-12-01
Hyperkalemia is a potentially life-threatening condition that is common in kidney disease patients. Insulin is used to treat hyperkalemia, but may cause hypoglycemia, especially in kidney disease when insulin may be metabolized more slowly. We compared the rates of hypoglycemia in patients with low estimated glomerular filtration rate (eGFR) using high versus low doses of insulin for hyperkalemia to determine if lower doses of insulin would decrease the incidence of hypoglycemia. This was a retrospective study of hospitalized patients receiving intravenous insulin for hyperkalemia during a 6-month period. Patients with low eGFR were analyzed based on how much insulin they received: high dose (10 units, n = 78) versus low dose (5 units, n = 71). Postdose nadir blood glucose values were examined for up to 8 hours after the dose. The percentage of hypoglycemia (blood glucose ≤70 mg/dl) and a subset of severe hypoglycemia (blood glucose <50 mg/dl) were then reported for each dose group. A total of 149 doses were identified in patients with low eGFR. The rates of hypoglycemia were 16.7% and 19.7% (P = 0.79), respectively, among high-dose (n = 78) and low-dose (n = 71) groups. Rates of severe hypoglycemia were 8.9% and 7.0%, respectively (P = 0.90). More than 28% of hypoglycemic episodes with high doses occurred after 4 hours (median = 2.5 hours) compared with 14.3% with low doses (median = 2.38 hours). There was no difference in the rate of hypoglycemia or severe hypoglycemia between high or low doses of insulin in patients with low eGFR. We recommend monitoring up to 6 hours after insulin use in hyperkalemia. © The Author(s) 2015.
I Dewa Gde Agung Budhi Udiana; I G Dyana Arjana; Tjok Gede Indra Partha
2017-01-01
Short circuit causing over current problem and can might causing interference of the equipment performance such as distribution transformers also causing widespread disruption occurred. In resolving such interference is required as protection system on the distribution system. Seeing all above is needed coordination between the supporting component of the protection system which is consisted of Over Current Relay (OCR) and Ground Fault Relay (GFR). The research was conducted at PT. PLN (Perse...
Equilibrium shoreface profiles
DEFF Research Database (Denmark)
Aagaard, Troels; Hughes, Michael G
2017-01-01
Large-scale coastal behaviour models use the shoreface profile of equilibrium as a fundamental morphological unit that is translated in space to simulate coastal response to, for example, sea level oscillations and variability in sediment supply. Despite a longstanding focus on the shoreface...... profile and its relevance to predicting coastal response to changing environmental conditions, the processes and dynamics involved in shoreface equilibrium are still not fully understood. Here, we apply a process-based empirical sediment transport model, combined with morphodynamic principles to provide......; there is no tuning or calibration and computation times are short. It is therefore easily implemented with repeated iterations to manage uncertainty....
Directory of Open Access Journals (Sweden)
Abdul Rauf Hafeez
2016-01-01
Full Text Available To determine the accuracy of estimated glomerular filtration rate (eGFR using the modification of diet in renal disease (MDRD, Cockcroft-Gault (CG, and chronic kidney disease epidemiology (CKD-EPI formulas in potential kidney donors compared with 24-h urine creatinine clearance, we studied 207 potential live kidney donors in our center. There were 126 (60.9% males and 81 (39.1% females. Male:female ratio was 1.6:1. The age of the donors ranged from 18-58 years, with mean age of 35.30 ± 9.23 years and most of the individuals were below 40 years of age. The body mass index (BMI was calculated and venous blood samples were obtained for the measurement of serum creatinine and every study participant was instructed to collect 24-h urine. GFR was calculated based on 24-h urine creatinine clearance and the formulas. The accuracy of GFR estimation formula was taken as positive if the GFR calculated by the formulas and urine creatinine clearance fell between 90-120 mL/min/1.73 m 2 . The accuracy of the MDRD formula was 48.8% and the CG formula was 41.5% whereas the accuracy of the CKD-EPI formula was 78.2%. The accuracy of the eGFR using the MDRD formula was significantly higher in males than females (57.9% vs. 33.3% P = 0.001, while there was no statistically significant difference in the eGFR between them in case of the use of the CG and the CKD-EPI formulas. BMI and obesity had no effect on the accuracy of eGFR by the use of the different formulas. The performance of GFR estimation formulas was sub optimal and these either underestimated and/or over-estimated the GFR in healthy subjects. CKD-EPI is closer to 24 -h urinary creatinine clearance in the calculation of eGFR. However, none of the eGFR formulas can be used in renal transplant donors because of their low accuracy, and 24-h urine creatinine clearance should be used for evaluation of the GFR in this population.
Microeconomics : Equilibrium and Efficiency
Ten Raa, T.
2013-01-01
Microeconomics: Equilibrium and Efficiency teaches how to apply microeconomic theory in an innovative, intuitive and concise way. Using real-world, empirical examples, this book not only covers the building blocks of the subject, but helps gain a broad understanding of microeconomic theory and
Differential Equation of Equilibrium
African Journals Online (AJOL)
user
ABSTRACT. Analysis of underground circular cylindrical shell is carried out in this work. The forth order differential equation of equilibrium, comparable to that of beam on elastic foundation, was derived from static principles on the assumptions of P. L Pasternak. Laplace transformation was used to solve the governing ...
Comments on equilibrium, transient equilibrium, and secular equilibrium in serial radioactive decay
International Nuclear Information System (INIS)
Prince, J.R.
1979-01-01
Equations describing serial radioactive decay are reviewed along with published descriptions or transient and secular equilibrium. It is shown that terms describing equilibrium are not used in the same way by various authors. Specific definitions are proposed; they suggest that secular equilibrium is a subset of transient equilibrium
DEFF Research Database (Denmark)
Møller, Grith; Sluik, Diewertje; Ritz, Christian
2017-01-01
with glycated haemoglobin (HbA1c) and estimated glomerular filtration rate (eGFR). Analyses were based on three population studies included in the PREVIEW project (PREVention of diabetes through lifestyle Intervention and population studies in Europe and around the World): NQplus, Lifelines, and the Young Finns.......02 ± 0.01 mmol/mol, p eGFR in Lifelines (slope 0.17 ± 0.02 mL/min/1.73 m², p
Equilibrium and pre-equilibrium emissions in proton-induced ...
Indian Academy of Sciences (India)
necessary for the domain of fission-reactor technology for the calculation of nuclear transmutation ... tions occur in three stages: INC, pre-equilibrium and equilibrium (or compound. 344. Pramana ... In the evaporation phase of the reaction, the.
Gated equilibrium bloodpool scintigraphy
International Nuclear Information System (INIS)
Reinders Folmer, S.C.C.
1981-01-01
This thesis deals with the clinical applications of gated equilibrium bloodpool scintigraphy, performed with either a gamma camera or a portable detector system, the nuclear stethoscope. The main goal has been to define the value and limitations of noninvasive measurements of left ventricular ejection fraction as a parameter of cardiac performance in various disease states, both for diagnostic purposes as well as during follow-up after medical or surgical intervention. Secondly, it was attempted to extend the use of the equilibrium bloodpool techniques beyond the calculation of ejection fraction alone by considering the feasibility to determine ventricular volumes and by including the possibility of quantifying valvular regurgitation. In both cases, it has been tried to broaden the perspective of the observations by comparing them with results of other, invasive and non-invasive, procedures, in particular cardiac catheterization, M-mode echocardiography and myocardial perfusion scintigraphy. (Auth.)
Problems in equilibrium theory
Aliprantis, Charalambos D
1996-01-01
In studying General Equilibrium Theory the student must master first the theory and then apply it to solve problems. At the graduate level there is no book devoted exclusively to teaching problem solving. This book teaches for the first time the basic methods of proof and problem solving in General Equilibrium Theory. The problems cover the entire spectrum of difficulty; some are routine, some require a good grasp of the material involved, and some are exceptionally challenging. The book presents complete solutions to two hundred problems. In searching for the basic required techniques, the student will find a wealth of new material incorporated into the solutions. The student is challenged to produce solutions which are different from the ones presented in the book.
VVER fuel cycle development at Slovakia
International Nuclear Information System (INIS)
Darilek, P.; Chrapiak, V.; Majerik, J.
1995-01-01
Four VVER-440 units are now under exploitation at Bohunice-site in Slovakia. Fuel cycle development of Unit No.3 and No.4 (type 213) is discussed and compared with equilibrium cycles in this paper. (author)
Equilibrium statistical mechanics
Jackson, E Atlee
2000-01-01
Ideal as an elementary introduction to equilibrium statistical mechanics, this volume covers both classical and quantum methodology for open and closed systems. Introductory chapters familiarize readers with probability and microscopic models of systems, while additional chapters describe the general derivation of the fundamental statistical mechanics relationships. The final chapter contains 16 sections, each dealing with a different application, ordered according to complexity, from classical through degenerate quantum statistical mechanics. Key features include an elementary introduction t
DEFF Research Database (Denmark)
Bollerslev, Tim; Sizova, Natalia; Tauchen, George
Stock market volatility clusters in time, carries a risk premium, is fractionally inte- grated, and exhibits asymmetric leverage effects relative to returns. This paper develops a first internally consistent equilibrium based explanation for these longstanding empirical facts. The model is cast i......, and the dynamic cross-correlations of the volatility measures with the returns calculated from actual high-frequency intra-day data on the S&P 500 aggregate market and VIX volatility indexes....
Molecular equilibrium with condensation
International Nuclear Information System (INIS)
Sharp, C.M.; Huebner, W.F.
1990-01-01
Minimization of the Gibbs energy of formation for species of chemical elements and compounds in their gas and condensed phases determines their relative abundances in a mixture in chemical equilibrium. The procedure is more general and more powerful than previous abundance determinations in multiphase astrophysical mixtures. Some results for astrophysical equations of state are presented, and the effects of condensation on opacity are briefly indicated. 18 refs
Equilibrium calculations, ch. 6
International Nuclear Information System (INIS)
Deursen, A.P.J. van
1976-01-01
A calculation is presented of dimer intensities obtained in supersonic expansions. There are two possible limiting considerations; the dimers observed are already present in the source, in thermodynamic equilibrium, and are accelerated in the expansion. Destruction during acceleration is neglected, as are processes leading to newly formed dimers. On the other hand one can apply a kinetic approach, where formation and destruction processes are followed throughout the expansion. The difficulty of this approach stems from the fact that the density, temperature and rate constants have to be known at all distances from the nozzle. The simple point of view has been adopted and the measured dimer intensities are compared with the equilibrium concentration in the source. The comparison is performed under the assumption that the detection efficiency for dimers is twice the detection efficiency for monomers. The experimental evidence against the simple point of view that the dimers of the onset region are formed in the source already, under equilibrium conditions, is discussed. (Auth.)
Resurrecting Equilibria Through Cycles
DEFF Research Database (Denmark)
Barnett, Richard C.; Bhattacharya, Joydeep; Bunzel, Helle
equilibria because they asymptotically violate some economic restriction of the model. The literature has always ruled out such paths. This paper studies a pure-exchange monetary overlapping generations economy in which real balances cycle forever between momentary equilibrium points. The novelty is to show...... that segments of the offer curve that have been previously ignored, can in fact be used to produce asymptotically valid cyclical paths. Indeed, a cycle can bestow dynamic validity on momentary equilibrium points that had erstwhile been classified as dynamically invalid....
Noncompact Equilibrium Points and Applications
Directory of Open Access Journals (Sweden)
Zahra Al-Rumaih
2012-01-01
Full Text Available We prove an equilibrium existence result for vector functions defined on noncompact domain and we give some applications in optimization and Nash equilibrium in noncooperative game.
Equilibrium thermodynamics - Callen's postulational approach
Jongschaap, R.J.J.; Öttinger, Hans Christian
2001-01-01
In order to provide the background for nonequilibrium thermodynamics, we outline the fundamentals of equilibrium thermodynamics. Equilibrium thermodynamics must not only be obtained as a special case of any acceptable nonequilibrium generalization but, through its shining example, it also elucidates
MHD equilibrium with toroidal rotation
International Nuclear Information System (INIS)
Li, J.
1987-03-01
The present work attempts to formulate the equilibrium of axisymmetric plasma with purely toroidal flow within ideal MHD theory. In general, the inertial term Rho(v.Del)v caused by plasma flow is so complicated that the equilibrium equation is completely different from the Grad-Shafranov equation. However, in the case of purely toroidal flow the equilibrium equation can be simplified so that it resembles the Grad-Shafranov equation. Generally one arbitrary two-variable functions and two arbitrary single variable functions, instead of only four single-variable functions, are allowed in the new equilibrium equations. Also, the boundary conditions of the rotating (with purely toroidal fluid flow, static - without any fluid flow) equilibrium are the same as those of the static equilibrium. So numerically one can calculate the rotating equilibrium as a static equilibrium. (author)
James, Matthew T; Grams, Morgan E; Woodward, Mark; Elley, C Raina; Green, Jamie A; Wheeler, David C; de Jong, Paul; Gansevoort, Ron T; Levey, Andrew S; Warnock, David G; Sarnak, Mark J
2015-10-01
Diabetes mellitus and hypertension are risk factors for acute kidney injury (AKI). Whether estimated glomerular filtration rate (eGFR) and urine albumin-creatinine ratio (ACR) remain risk factors for AKI in the presence and absence of these conditions is uncertain. Meta-analysis of cohort studies. 8 general-population (1,285,045 participants) and 5 chronic kidney disease (CKD; 79,519 participants) cohorts. Cohorts participating in the CKD Prognosis Consortium. Diabetes and hypertension status, eGFR by the 2009 CKD Epidemiology Collaboration creatinine equation, urine ACR, and interactions. Hospitalization with AKI, using Cox proportional hazards models to estimate HRs of AKI and random-effects meta-analysis to pool results. During a mean follow-up of 4 years, there were 16,480 episodes of AKI in the general-population and 2,087 episodes in the CKD cohorts. Low eGFRs and high ACRs were associated with higher risks of AKI in individuals with or without diabetes and with or without hypertension. When compared to a common reference of eGFR of 80mL/min/1.73m(2) in nondiabetic patients, HRs for AKI were generally higher in diabetic patients at any level of eGFR. The same was true for diabetic patients at all levels of ACR compared with nondiabetic patients. The risk gradient for AKI with lower eGFRs was greater in those without diabetes than with diabetes, but similar with higher ACRs in those without versus with diabetes. Those with hypertension had a higher risk of AKI at eGFRs>60mL/min/1.73m(2) than those without hypertension. However, risk gradients for AKI with both lower eGFRs and higher ACRs were greater for those without than with hypertension. AKI identified by diagnostic code. Lower eGFRs and higher ACRs are associated with higher risks of AKI among individuals with or without either diabetes or hypertension. Copyright © 2015 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.
Directory of Open Access Journals (Sweden)
Farook Thameem
Full Text Available Estimated glomerular filtration rate (eGFR, a measure of kidney function, is heritable, suggesting that genes influence renal function. Genes that influence eGFR have been identified through genome-wide association studies. However, family-based linkage approaches may identify loci that explain a larger proportion of the heritability. This study used genome-wide linkage and association scans to identify quantitative trait loci (QTL that influence eGFR.Genome-wide linkage and sparse association scans of eGFR were performed in families ascertained by probands with advanced diabetic nephropathy (DN from the multi-ethnic Family Investigation of Nephropathy and Diabetes (FIND study. This study included 954 African Americans (AA, 781 American Indians (AI, 614 European Americans (EA and 1,611 Mexican Americans (MA. A total of 3,960 FIND participants were genotyped for 6,000 single nucleotide polymorphisms (SNPs using the Illumina Linkage IVb panel. GFR was estimated by the Modification of Diet in Renal Disease (MDRD formula.The non-parametric linkage analysis, accounting for the effects of diabetes duration and BMI, identified the strongest evidence for linkage of eGFR on chromosome 20q11 (log of the odds [LOD] = 3.34; P = 4.4 × 10(-5 in MA and chromosome 15q12 (LOD = 2.84; P = 1.5 × 10(-4 in EA. In all subjects, the strongest linkage signal for eGFR was detected on chromosome 10p12 (P = 5.5 × 10(-4 at 44 cM near marker rs1339048. A subsequent association scan in both ancestry-specific groups and the entire population identified several SNPs significantly associated with eGFR across the genome.The present study describes the localization of QTL influencing eGFR on 20q11 in MA, 15q21 in EA and 10p12 in the combined ethnic groups participating in the FIND study. Identification of causal genes/variants influencing eGFR, within these linkage and association loci, will open new avenues for functional analyses and development of novel diagnostic markers
Thameem, Farook; Igo, Robert P; Freedman, Barry I; Langefeld, Carl; Hanson, Robert L; Schelling, Jeffrey R; Elston, Robert C; Duggirala, Ravindranath; Nicholas, Susanne B; Goddard, Katrina A B; Divers, Jasmin; Guo, Xiuqing; Ipp, Eli; Kimmel, Paul L; Meoni, Lucy A; Shah, Vallabh O; Smith, Michael W; Winkler, Cheryl A; Zager, Philip G; Knowler, William C; Nelson, Robert G; Pahl, Madeline V; Parekh, Rulan S; Kao, W H Linda; Rasooly, Rebekah S; Adler, Sharon G; Abboud, Hanna E; Iyengar, Sudha K; Sedor, John R
2013-01-01
Estimated glomerular filtration rate (eGFR), a measure of kidney function, is heritable, suggesting that genes influence renal function. Genes that influence eGFR have been identified through genome-wide association studies. However, family-based linkage approaches may identify loci that explain a larger proportion of the heritability. This study used genome-wide linkage and association scans to identify quantitative trait loci (QTL) that influence eGFR. Genome-wide linkage and sparse association scans of eGFR were performed in families ascertained by probands with advanced diabetic nephropathy (DN) from the multi-ethnic Family Investigation of Nephropathy and Diabetes (FIND) study. This study included 954 African Americans (AA), 781 American Indians (AI), 614 European Americans (EA) and 1,611 Mexican Americans (MA). A total of 3,960 FIND participants were genotyped for 6,000 single nucleotide polymorphisms (SNPs) using the Illumina Linkage IVb panel. GFR was estimated by the Modification of Diet in Renal Disease (MDRD) formula. The non-parametric linkage analysis, accounting for the effects of diabetes duration and BMI, identified the strongest evidence for linkage of eGFR on chromosome 20q11 (log of the odds [LOD] = 3.34; P = 4.4 × 10(-5)) in MA and chromosome 15q12 (LOD = 2.84; P = 1.5 × 10(-4)) in EA. In all subjects, the strongest linkage signal for eGFR was detected on chromosome 10p12 (P = 5.5 × 10(-4)) at 44 cM near marker rs1339048. A subsequent association scan in both ancestry-specific groups and the entire population identified several SNPs significantly associated with eGFR across the genome. The present study describes the localization of QTL influencing eGFR on 20q11 in MA, 15q21 in EA and 10p12 in the combined ethnic groups participating in the FIND study. Identification of causal genes/variants influencing eGFR, within these linkage and association loci, will open new avenues for functional analyses and development of novel diagnostic markers
Non-equilibrium thermodynamics
De Groot, Sybren Ruurds
1984-01-01
The study of thermodynamics is especially timely today, as its concepts are being applied to problems in biology, biochemistry, electrochemistry, and engineering. This book treats irreversible processes and phenomena - non-equilibrium thermodynamics.S. R. de Groot and P. Mazur, Professors of Theoretical Physics, present a comprehensive and insightful survey of the foundations of the field, providing the only complete discussion of the fluctuating linear theory of irreversible thermodynamics. The application covers a wide range of topics: the theory of diffusion and heat conduction, fluid dyn
Energy Technology Data Exchange (ETDEWEB)
Weaver, Virginia M., E-mail: vweaver@jhsph.edu [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD (United States); Johns Hopkins University School of Medicine, Baltimore, MD (United States); Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD (United States); Vargas, Gonzalo García [Faculty of Medicine, University of Juárez of Durango State, Durango (Mexico); Secretaría de Salud del Estado de Coahuila, Coahuila, México (Mexico); Silbergeld, Ellen K. [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD (United States); Rothenberg, Stephen J. [Instituto Nacional de Salud Publica, Centro de Investigacion en Salud Poblacional, Cuernavaca, Morelos (Mexico); Fadrowski, Jeffrey J. [Johns Hopkins University School of Medicine, Baltimore, MD (United States); Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD (United States); Rubio-Andrade, Marisela [Faculty of Medicine, University of Juárez of Durango State, Durango (Mexico); Parsons, Patrick J. [Laboratory of Inorganic and Nuclear Chemistry, Wadsworth Center, New York State Department of Health, Albany, NY (United States); Department of Environmental Health Sciences, School of Public Health, University at Albany, Albany, NY (United States); Steuerwald, Amy J. [Laboratory of Inorganic and Nuclear Chemistry, Wadsworth Center, New York State Department of Health, Albany, NY (United States); and others
2014-07-15
Positive associations between urine toxicant levels and measures of glomerular filtration rate (GFR) have been reported recently in a range of populations. The explanation for these associations, in a direction opposite that of traditional nephrotoxicity, is uncertain. Variation in associations by urine concentration adjustment approach has also been observed. Associations of urine cadmium, thallium and uranium in models of serum creatinine- and cystatin-C-based estimated GFR (eGFR) were examined using multiple linear regression in a cross-sectional study of adolescents residing near a lead smelter complex. Urine concentration adjustment approaches compared included urine creatinine, urine osmolality and no adjustment. Median age, blood lead and urine cadmium, thallium and uranium were 13.9 years, 4.0 μg/dL, 0.22, 0.27 and 0.04 g/g creatinine, respectively, in 512 adolescents. Urine cadmium and thallium were positively associated with serum creatinine-based eGFR only when urine creatinine was used to adjust for urine concentration (β coefficient=3.1 mL/min/1.73 m{sup 2}; 95% confidence interval=1.4, 4.8 per each doubling of urine cadmium). Weaker positive associations, also only with urine creatinine adjustment, were observed between these metals and serum cystatin-C-based eGFR and between urine uranium and serum creatinine-based eGFR. Additional research using non-creatinine-based methods of adjustment for urine concentration is necessary. - Highlights: • Positive associations between urine metals and creatinine-based eGFR are unexpected. • Optimal approach to urine concentration adjustment for urine biomarkers uncertain. • We compared urine concentration adjustment methods. • Positive associations observed only with urine creatinine adjustment. • Additional research using non-creatinine-based methods of adjustment needed.
International Nuclear Information System (INIS)
Weaver, Virginia M.; Vargas, Gonzalo García; Silbergeld, Ellen K.; Rothenberg, Stephen J.; Fadrowski, Jeffrey J.; Rubio-Andrade, Marisela; Parsons, Patrick J.; Steuerwald, Amy J.
2014-01-01
Positive associations between urine toxicant levels and measures of glomerular filtration rate (GFR) have been reported recently in a range of populations. The explanation for these associations, in a direction opposite that of traditional nephrotoxicity, is uncertain. Variation in associations by urine concentration adjustment approach has also been observed. Associations of urine cadmium, thallium and uranium in models of serum creatinine- and cystatin-C-based estimated GFR (eGFR) were examined using multiple linear regression in a cross-sectional study of adolescents residing near a lead smelter complex. Urine concentration adjustment approaches compared included urine creatinine, urine osmolality and no adjustment. Median age, blood lead and urine cadmium, thallium and uranium were 13.9 years, 4.0 μg/dL, 0.22, 0.27 and 0.04 g/g creatinine, respectively, in 512 adolescents. Urine cadmium and thallium were positively associated with serum creatinine-based eGFR only when urine creatinine was used to adjust for urine concentration (β coefficient=3.1 mL/min/1.73 m 2 ; 95% confidence interval=1.4, 4.8 per each doubling of urine cadmium). Weaker positive associations, also only with urine creatinine adjustment, were observed between these metals and serum cystatin-C-based eGFR and between urine uranium and serum creatinine-based eGFR. Additional research using non-creatinine-based methods of adjustment for urine concentration is necessary. - Highlights: • Positive associations between urine metals and creatinine-based eGFR are unexpected. • Optimal approach to urine concentration adjustment for urine biomarkers uncertain. • We compared urine concentration adjustment methods. • Positive associations observed only with urine creatinine adjustment. • Additional research using non-creatinine-based methods of adjustment needed
Adebisi, Simeon A
2013-03-01
Chronic Kidney Disease (CKD) is defined as the presence of markers of kidney damage or of estimated glomerular filtration rate (eGFR)clinical practice. Current guidelines advocate the use of prediction equations, such as the Cockcroft-Gault (CG) formula and the Modification of Diet in Renal Disease (MDRD) study-derived equations. Laboratories in African should commence routine reporting of eGFR for a number of reasons; 1. The sensitivity of serum creatinine (Scr) in identifying CKD is low.2. In Nigeria, a representative country; screening for Chronic Kidney Disease (CKD) is hardly considered in the routine practice of the primary and secondary care medical officers.3 Studies have shown that routine reporting of eGFR improved the documentation and identification of CKD by almost 50%.4 There is the possibility of reversing CKD if picked earlier.5. The high cost of treating CKD patients in advanced stages and the low per capital income status of the populace in Sub-Saharan Africa.6. Poor health infrastructure to manage advanced CKD patients in the continent.7. Several studies, now show lack of awareness of CKD among non-nephrologists that is related, at least in part, to difficulty in interpreting serum creatinine concentrations (the reciprocal, non-linear relationship between GFR and serum creatinine).8 Mathematical estimates of GFR [ as in eGFR] that incorporate creatinine concentration, as well as factors affecting creatinine production rates, such as size, gender, age and ethnic background, are more sensitive to changes in renal function than serum creatinine value alone.9 Recent guidelines define "action plans" for CKD according to the GFR, including referral to nephrologists at GFRs<30 mL.min(-1).(1.73 m2).
Endre, Zoltán H; Pianta, Timothy J; Pickering, John W
2016-01-01
Post transplant repeated measurements of urine volume and serum creatinine (sCr) are used to assess kidney function. Under non-steady state conditions, repeated measurement of sCr allows calculation of the kinetic estimated GFR (KeGFR). Additional measurement of urinary creatinine allows the calculation of the creatinine excretion to (estimated) production ratio (E/eG). We hypothesized that post-transplant KeGFR and E/eG would predict delayed graft function (DGF), as early as 4 h and outperform a validated clinical model at 12 h. This was a retrospective analysis of prospectively acquired data in a study of 56 recipients of deceased-donor kidney transplant. We assessed predictive performance with the area under the receiver operator characteristic curve (AUC) and the added value to a clinical model with integrated discrimination improvement analysis. At 4 h, the AUC for E/eG was 0.87 (95% CI 0.77-0.96) and for KeGFR 0.69 (95% CI 0.56-0.83). Both E/eG and KeGFR improved the risk prediction of a clinical model for DGF by 32 and 18%, and for non-DGF by 17 and 10%, respectively. While E/eG had better predictive performance of DGF than KeGFR, KeGFR might also facilitate perioperative management including drug dosing after kidney transplantation. Together these measurements may facilitate the possibility of conducting trials of early intervention to ameliorate the adverse effects of ischaemia-reperfusion injury on long-term DGF. © 2016 S. Karger AG, Basel.
Stevens, Lesley A; Schmid, Christopher H; Greene, Tom; Zhang, Yaping Lucy; Beck, Gerald J; Froissart, Marc; Hamm, Lee L; Lewis, Julia B; Mauer, Michael; Navis, Gerjan J; Steffes, Michael W; Eggers, Paul W; Coresh, Josef; Levey, Andrew S
2010-09-01
The Modification of Diet in Renal Disease (MDRD) Study equation underestimates measured glomerular filtration rate (GFR) at levels>60 mL/min/1.73 m2, with variable accuracy among subgroups; consequently, estimated GFR (eGFR)>or=60 mL/min/1.73 m2 is not reported by clinical laboratories. Here, performance of a more accurate GFR-estimating equation, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, is reported by level of GFR and clinical characteristics. Test of diagnostic accuracy. Pooled data set of 3,896 people from 16 studies with measured GFR (not used for the development of either equation). Subgroups were defined by eGFR, age, sex, race, diabetes, prior solid-organ transplant, and body mass index. eGFR from the CKD-EPI and MDRD Study equations and standardized serum creatinine. Measured GFR using urinary or plasma clearance of exogenous filtration markers. Mean measured GFR was 68+/-36 (SD) mL/min/1.73 m2. For eGFR73 m2, both equations have similar bias (median difference compared with measured GFR). For eGFR of 30-59 mL/min/1.73 m2, bias was decreased from 4.9 to 2.1 mL/min/1.73 m2 (57% improvement). For eGFR of 60-89 mL/min/1.73 m2, bias was decreased from 11.9 to 4.2 mL/min/1.73 m2 (61% improvement). For eGFR of 90-119 mL/min/1.73 m2, bias was decreased from 10.0 to 1.9 mL/min/1.73 m2 (75% improvement). Similar or improved performance was noted for most subgroups with eGFR73 m2, other than body mass indexor=90 mL/min/1.73 m2. Limited number of elderly people and racial and ethnic minorities with measured GFR. The CKD-EPI equation is more accurate than the MDRD Study equation overall and across most subgroups. In contrast to the MDRD Study equation, eGFR>or=60 mL/min/1.73 m2 can be reported using the CKD-EPI equation. Copyright (c) 2010 National Kidney Foundation, Inc. All rights reserved.
Maia, Alex S C; Nascimento, Sheila T; Nascimento, Carolina C N; Gebremedhin, Kifle G
2016-05-01
The effects of air temperature and relative humidity on thermal equilibrium of goats in a tropical region was evaluated. Nine non-pregnant Anglo Nubian nanny goats were used in the study. An indirect calorimeter was designed and developed to measure oxygen consumption, carbon dioxide production, methane production and water vapour pressure of the air exhaled from goats. Physiological parameters: rectal temperature, skin temperature, hair-coat temperature, expired air temperature and respiratory rate and volume as well as environmental parameters: air temperature, relative humidity and mean radiant temperature were measured. The results show that respiratory and volume rates and latent heat loss did not change significantly for air temperature between 22 and 26°C. In this temperature range, metabolic heat was lost mainly by convection and long-wave radiation. For temperature greater than 30°C, the goats maintained thermal equilibrium mainly by evaporative heat loss. At the higher air temperature, the respiratory and ventilation rates as well as body temperatures were significantly elevated. It can be concluded that for Anglo Nubian goats, the upper limit of air temperature for comfort is around 26°C when the goats are protected from direct solar radiation. Copyright © 2016 Elsevier Ltd. All rights reserved.
Gas-cooled Fast Reactor (GFR) fuel and In-Core Fuel Management
International Nuclear Information System (INIS)
Weaver, K.D.; Sterbentz, J.; Meyer, M.; Lowden, R.; Hoffman, E.; Wei, T.Y.C.
2004-01-01
The Gas-Cooled Fast Reactor (GCFR) has been chosen as one of six candidates for development as a Generation IV nuclear reactor based on: its ability to fully utilize fuel resources; minimize or reduce its own (and other systems) actinide inventory; produce high efficiency electricity; and the possibility to utilize high temperature process heat. Current design approaches include a high temperature (2 850 C) helium cooled reactor using a direct Brayton cycle, and a moderate temperature (550 C - 650 C) helium or supercritical carbon dioxide (S-CO 2 ) cooled reactor using direct or indirect Brayton cycles. These design choices have thermal efficiencies that approach 45% to 50%, and have turbomachinery sizes that are much more compact compared to steam plants. However, there are challenges associated with the GCFR, which are the focus of current research. This includes safety system design for decay heat removal, development of high temperature/high fluence fuels and materials, and development of fuel cycle strategies. The work presented here focuses on the fuel and preliminary in-core fuel management, where advanced ceramic-ceramic (cercer) dispersion fuels are the main focus, and average burnups to 266 M Wd/kg appear achievable for the reference Si C/(U,TRU)C block/plate fuel. Solid solution (pellet) fuel in composite ceramic clad (Si C/Si C) is also being considered, but remains as a backup due to cladding fabrication challenges, and high centerline temperatures in the fuel. (Author)
Current design efforts for the gas-cooled fast reactor (GFR)
International Nuclear Information System (INIS)
Weaver, K.D.
2005-01-01
Current research and development on the Gas-Cooled Fast Reactor (GCFR) has focused on the design of safety systems that will remove the decay heat during accident conditions, ion irradiations of candidate ceramic materials, joining studies of oxide dispersion strengthened alloys; and within the Advanced Fuel Cycle Initiative (AFC I) the fabrication of carbide fuels and ceramic fuel matrix materials, development of non-halide precursor low density and high density ceramic coatings, and neutron irradiation of candidate ceramic fuel matrix and metallic materials. The vast majority of this work has focused on the reference design for the GCFR: a helium-cooled, direct Brayton cycle power conversion system that will operate with an outlet temperature of 850 C at 7 MPa. In addition to the work being performed in the United States, seven international partners under the Generation IV International Forum (GIF) have identified their interest in participating in research related to the development of the GCFR. These are EURATOM (European Commission), France, Japan, South Africa, South Korea, Switzerland, and the United Kingdom. Of these, EURATOM (including the United Kingdom), France, Japan, and Switzerland have active research activities with respect to the GCFR. The research includes GCFR design and safety, and fuels/in-core materials/fuel cycle projects. This paper outlines the current design status of the GCFR, and includes work done in the areas mentioned above. (Author)
Physical model of the nuclear fuel cycle simulation code SITON
International Nuclear Information System (INIS)
Brolly, Á.; Halász, M.; Szieberth, M.; Nagy, L.; Fehér, S.
2017-01-01
Finding answers to main challenges of nuclear energy, like resource utilisation or waste minimisation, calls for transient fuel cycle modelling. This motivation led to the development of SITON v2.0 a dynamic, discrete facilities/discrete materials and also discrete events fuel cycle simulation code. The physical model of the code includes the most important fuel cycle facilities. Facilities can be connected flexibly; their number is not limited. Material transfer between facilities is tracked by taking into account 52 nuclides. Composition of discharged fuel is determined using burnup tables except for the 2400 MW thermal power design of the Gas-Cooled Fast Reactor (GFR2400). For the GFR2400 the FITXS method is used, which fits one-group microscopic cross-sections as polynomial functions of the fuel composition. This method is accurate and fast enough to be used in fuel cycle simulations. Operation of the fuel cycle, i.e. material requests and transfers, is described by discrete events. In advance of the simulation reactors and plants formulate their requests as events; triggered requests are tracked. After that, the events are simulated, i.e. the requests are fulfilled and composition of the material flow between facilities is calculated. To demonstrate capabilities of SITON v2.0, a hypothetical transient fuel cycle is presented in which a 4-unit VVER-440 reactor park was replaced by one GFR2400 that recycled its own spent fuel. It is found that the GFR2400 can be started if the cooling time of its spent fuel is 2 years. However, if the cooling time is 5 years it needs an additional plutonium feed, which can be covered from the spent fuel of a Generation III light water reactor.
Blute, Michael L; Kucherov, Victor; Rushmer, Timothy J; Damodaran, Shivashankar; Shi, Fangfang; Abel, E Jason; Jarrard, David F; Richards, Kyle A; Messing, Edward M; Downs, Tracy M
2017-09-01
To evaluate if moderate chronic kidney disease [CKD; estimated glomerular filtration rate (eGFR) 73 m 2 ] is associated with high rates of non-muscle-invasive bladder cancer (NMIBC) recurrence or progression. A multi-institutional database identified patients with serum creatinine values prior to first transurethral resection of bladder tumour (TURBT). The CKD-epidemiology collaboration formula calculated patient eGFR. Cox proportional hazards models evaluated associations with recurrence-free (RFS) and progression-free survival (PFS). In all, 727 patients were identified with a median (interquartile range [IQR]) patient age of 69.8 (60.1-77.6) years. Data for eGFR were available for 632 patients. During a median (IQR) follow-up of 3.7 (1.5-6.5) years, 400 (55%) patients had recurrence and 145 (19.9%) patients had progression of tumour stage or grade. Moderate or severe CKD was identified in 183 patients according to eGFR. Multivariable analysis identified an eGFR of 73 m 2 (hazard ratio [HR] 1.5, 95% confidence interval [CI]: 1.2-1.9; P = 0.002) as a predictor of tumour recurrence. The 5-year RFS rate was 46% for patients with an eGFR of ≥60 mL/min/1.73 m 2 and 27% for patients with an eGFR of 73 m 2 (P 73 m 2 (HR 3.7, 95% CI: 1.75-7.94; P = 0.001) was associated with progression to muscle-invasive disease. The 5-year PFS rate was 83% for patients with an eGFR of ≥60 mL/min/1.73 m 2 and 71% for patients with an eGFR of 73 m 2 (P = 0.01). Moderate CKD at first TURBT is associated with reduced RFS and PFS. Patients with reduced renal function should be considered for increased surveillance. © 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.
Boundedly rational credit cycles
Sáez, María
1996-01-01
We propose an evolutionary model of a credit market. We show that the economy exhibits credit cycles. The model predicts dynamics which are consistent with some evidence about the Great Depression. Real shocks trigger episodes of credit--crunch which are observed in the process of adjustment towards the post shock equilibrium.
DEFF Research Database (Denmark)
Busato, Francesco; Marchetti, Enrico
This paper explores the ability of a class of one-sector,multi-input models to generate indeterminate equilibrium paths, andendogenous cycles, without relying on factors' hoarding. The modelpresents a novel theoretical economic mechanism that supportssunspot-driven expansions without requiring...
International Nuclear Information System (INIS)
Girardin, G.
2009-01-01
Among the systems selected by the GIF, the Gas-cooled Fast Reactor (GFR) is a highly innovative system with advanced fuel geometry and materials. It is in the context of the large, 2400 MWth reference GFR design that the present doctoral research has been conducted, the principal aim having been to develop and qualify the control assembly (CA) pattern and corresponding CA implementation scheme for this system. The work has been carried out in three successive and complementary phases: (1) validation of the neutronics tools, (2) the CA pattern development and related static analysis, and (3) dynamic core behavior studies for hypothetical CA driven transients. During the first phase of the thesis, the reference PROTEUS test lattice from these experiments has been analyzed with ERANOS-2.0 and its associated, adjusted nuclear data library ERALIB1. Additionally, benchmark calculations were performed with the Monte Carlo code MCNPX, allowing one to both check the deterministic results and to analyze the sensitivity to different modern data libraries. It has been found that, for the main reaction rate ratios, the new analysis of the GCFR-PROTEUS reference lattice generally yields good agreement - within 1σ measurement uncertainty - with experimental values and with the Monte Carlo simulations. As shown by the analysis, the predictions were in somewhat better agreement in the case of the adjusted ERALIB1 library. The applicability of ERANOS-2.0/ERALIB1 as the reference neutronics tool for the GFR analysis could thus be demonstrated. Furthermore, neutronics aspects related to the novel features of the GFR, for which new experimental investigations are needed, were highlighted. In the second phase of the research, the CA pattern was developed for the GFR, based on iterative neutronics and thermal-hydraulics calculations, 2D and 3D neutronics models for the reactor core having first been set up using the reference ERANOS-2.0/ERALIB1 computational scheme. For the thermal
Equilibrium models and variational inequalities
Konnov, Igor
2007-01-01
The concept of equilibrium plays a central role in various applied sciences, such as physics (especially, mechanics), economics, engineering, transportation, sociology, chemistry, biology and other fields. If one can formulate the equilibrium problem in the form of a mathematical model, solutions of the corresponding problem can be used for forecasting the future behavior of very complex systems and, also, for correcting the the current state of the system under control. This book presents a unifying look on different equilibrium concepts in economics, including several models from related sciences.- Presents a unifying look on different equilibrium concepts and also the present state of investigations in this field- Describes static and dynamic input-output models, Walras, Cassel-Wald, spatial price, auction market, oligopolistic equilibrium models, transportation and migration equilibrium models- Covers the basics of theory and solution methods both for the complementarity and variational inequality probl...
Grinding kinetics and equilibrium states
Opoczky, L.; Farnady, F.
1984-01-01
The temporary and permanent equilibrium occurring during the initial stage of cement grinding does not indicate the end of comminution, but rather an increased energy consumption during grinding. The constant dynamic equilibrium occurs after a long grinding period indicating the end of comminution for a given particle size. Grinding equilibrium curves can be constructed to show the stages of comminution and agglomeration for certain particle sizes.
Mental Equilibrium and Rational Emotions
Eyal Winter; Ignacio Garcia-Jurado; Jose Mendez-Naya; Luciano Mendez-Naya
2009-01-01
We introduce emotions into an equilibrium notion. In a mental equilibrium each player "selects" an emotional state which determines the player's preferences over the outcomes of the game. These preferences typically differ from the players' material preferences. The emotional states interact to play a Nash equilibrium and in addition each player's emotional state must be a best response (with respect to material preferences) to the emotional states of the others. We discuss the concept behind...
Para-equilibrium phase diagrams
International Nuclear Information System (INIS)
Pelton, Arthur D.; Koukkari, Pertti; Pajarre, Risto; Eriksson, Gunnar
2014-01-01
Highlights: • A rapidly cooled system may attain a state of para-equilibrium. • In this state rapidly diffusing elements reach equilibrium but others are immobile. • Application of the Phase Rule to para-equilibrium phase diagrams is discussed. • A general algorithm to calculate para-equilibrium phase diagrams is described. - Abstract: If an initially homogeneous system at high temperature is rapidly cooled, a temporary para-equilibrium state may result in which rapidly diffusing elements have reached equilibrium but more slowly diffusing elements have remained essentially immobile. The best known example occurs when homogeneous austenite is quenched. A para-equilibrium phase assemblage may be calculated thermodynamically by Gibbs free energy minimization under the constraint that the ratios of the slowly diffusing elements are the same in all phases. Several examples of calculated para-equilibrium phase diagram sections are presented and the application of the Phase Rule is discussed. Although the rules governing the geometry of these diagrams may appear at first to be somewhat different from those for full equilibrium phase diagrams, it is shown that in fact they obey exactly the same rules with the following provision. Since the molar ratios of non-diffusing elements are the same in all phases at para-equilibrium, these ratios act, as far as the geometry of the diagram is concerned, like “potential” variables (such as T, pressure or chemical potentials) rather than like “normal” composition variables which need not be the same in all phases. A general algorithm to calculate para-equilibrium phase diagrams is presented. In the limit, if a para-equilibrium calculation is performed under the constraint that no elements diffuse, then the resultant phase diagram shows the single phase with the minimum Gibbs free energy at any point on the diagram; such calculations are of interest in physical vapor deposition when deposition is so rapid that phase
International Nuclear Information System (INIS)
Mittal, B.R.; Bhattacharya, A.; Singh, B.; Jha, V.; Sarika, Kumar R.
2007-01-01
Assessment of Glomerular filtration rate (GFR) has significant impact on both prognosis and treatment of patients with renal disease. In this study we compared the two-plasma-sample method (G2S) using a MS excel spreadsheet based program, with a manual five-plasmasample method (GS) used to measure GFR by determining Tc-99m-diethylenetriamine penta-acetic acid (Tc-99m DTPA) clearance in patients with chronic kidney disease (CKD) and healthy renal donors. The study was conducted in 148 subjects (64 men and 84 women; age range 14 to 70 yr); 59 patients of CKD and 89 prospective healthy kidney donors. Tc-99m DTPA (74-100 MBq) was injected intravenously and thereafter blood samples were obtained at 60, 90, 120, 150 and 180 min via the patent venflon. Radioactivity in the injection syringe and plasma was measured by means of a multi-well gamma counter. The correlation coefficient between the 2 methods was 0.9453, with a slope of 0.90 and an intercept of 14.72 mL/min. Bland Altman plot of disagreement showed that G2S underestimated the GFR values by 9.0 ml/min, 11.3 ml/min and 6.9 ml/min, in the entire study, CKD and healthy donor groups respectively. Our results indicate that in spite of good correlation between GS and G2S method, the G2S method constantly underestimated GFR in our study population. However, regression equation may be applied to the GFR values estimated by G2S method to match the GFR determined by GS method. (author)
Lin, Hsing-Hua; Chou, Shan-An; Yang, Hsiao-Yu; Hwang, Yaw-Huei; Kuo, Ching-Hua; Kao, Tze-Wah; Lo, Tsai-Chang; Chen, Pau-Chung
2013-08-01
This study was undertaken to explore the association of estimated glomerular filtration rate (GFR) with exposure to aristolochic acids (ALAs) and nephrotoxic metals in herbalists after the ban of herbs containing ALAs in Taiwan. This cross-sectional study recruited a total of 138 herbalists without end-stage renal disease or urothelial carcinoma from the Occupational Union of Chinese Herbalists in Taiwan in 2007. Aristolochic acid I (ALA-I) was measured by ultra-high-pressure liquid chromatography/ tandem mass spectrometry (UHPLC-MS/MS) and heavy metals in blood samples were analysed by Agilent 7500C inductively coupled plasma-mass spectrometry. Renal function was assessed by using a simplified Modification of Diet in Renal Disease Study equation to estimate GFR. Blood lead was higher in herbal dispensing procedures (p=0.053) and in subjects who self-prescribe herbal medicine (p=0.057); mercury was also higher in subjects living in the workplace (p=0.03). Lower estimated GFR was significantly associated with lead (β=-10.66, 95% CI -18.7 to -2.6) and mercury (β=-12.52, 95% CI -24.3 to -0.8) with a significant interaction (p=0.01) between mercury and lead; however, estimated GFR was not significantly associated with high ALA-I level groups, arsenic and cadmium after adjusting for other confounding factors. We found that lower estimated GFR was associated with blood lead and mercury in herbalists after the ban of herbs containing ALAs in Taiwan. The ALA-I exposure did not show a significant negative association of estimated GFR, which might due to herbalists having known how to distinguish ALA herbs after the banning policy. Rigorous monitoring is still needed to protect herbalists and the general population who take herbs.
Directory of Open Access Journals (Sweden)
Marianna Caterino
2018-03-01
Full Text Available Background:/Aims: Renal disease is a common cause of morbidity in patients with Bardet-Biedl syndrome (BBS, however the severity of kidney dysfunction is highly variable. To date, there is little information on the pathogenesis, the risk and predictor factors for poor renal outcome in this setting. The present study aims to analyze the spectrum of urinary proteins in BBS patients, in order to potentially identify 1 disease-specific proteomic profiles that may differentiate the patients from normal subjects; 2 urinary markers of renal dysfunction. Methods: Fourteen individuals (7 males and 7 females with a clinical diagnosis of BBS have been selected in this study. A pool of 10 aged-matched males and 10 aged-matched females have been used as controls for proteomic analysis. The glomerular filtration rate (eGFR has been estimated using the CKD-EPI formula. Variability of eGFR has been retrospectively assessed calculating average annual eGFR decline (ΔeGFR in a mean follow-up period of 4 years (3-7. Results: 42 proteins were significantly over- or under-represented in BBS patients compared with controls; the majority of these proteins are involved in fibrosis, cell adhesion and extracellular matrix organization. Statistic studies revealed a significant correlation between urine fibronectin (u-FN (r2=0.28; p<0.05, CD44 antigen (r2 =0.35; p<0.03 and lysosomal alfa glucosidase ( r20.27; p<0.05 abundance with the eGFR. In addition, u-FN (r2 =0.2389; p<0.05 was significantly correlated with ΔeGFR. Conclusion: The present study demonstrates that urine proteome of BBS patients differs from that of normal subjects; in addition, kidney dysfunction correlated with urine abundance of known markers of renal fibrosis.
Fuel cycle parameters for strategy studies
International Nuclear Information System (INIS)
Archinoff, G.H.
1979-05-01
This report summarizes seven fuel cycle parameters (efficiency, specific power, burnup, equilibrium net fissile feed, equilibrium net fissile surplus, first charge fissile content, and whether or not fuel reprocessing is required) to be used in long-term strategy analyses of fuel cycles based on natural UO 2 , low enriched uranium, mixed oxides, plutonium topped thorium, uranium topped thorium, and the fast breeder oxide cycle. (LL)
Directory of Open Access Journals (Sweden)
Ching-Wei Tsai
Full Text Available This study examined the progression of chronic kidney disease (CKD by using average annual decline in estimated GFR (eGFR and its risk factors in a 10-year follow-up CKD cohort.A prospective, observational cohort study, 4600 individuals fulfilled the definition of CKD, with or without proteinuria, were followed for 10 years. The eGFR was estimated by the MDRD equation. Linear regression was used to estimate participants' annual decline rate in eGFR. We defined subjects with annual eGFR decline rate <1 ml/min/1.73 m2 as non-progression and the decline rate over 3 ml/min/1.73 m2 as rapid progression.During the follow-up period, 2870 (62.4% individuals had annual eGFR decline rate greater than 1 ml/min/1.73 m2. The eGFR decline rate was slower in individuals with CKD diagnosed over the age of 60 years than those with onset at a younger age. Comparing to subjects with decline rate <1 ml/min/1.73 m2/year, the odds ratio (OR of developing rapid CKD progression for diabetes, proteinuria and late onset of CKD was 1.72 (95% CI: 1.48-2.00, 1.89(1.63-2.20 and 0.68 (0.56-0.81, respectively. When the model was adjusted for the latest CKD stage, comparing to those with CKD stage 1, patients with stage 4 and stage 5 have significantly higher risks for rapid progression (OR, 5.17 (2.60-10.25, 19.83 (10.05-39.10, respectively. However, such risk was not observed among patients with the latest CKD stage 2 and 3. The risk for incident ESRD was 17% higher for each 1 ml/min/1.73 m2 increasing in annual decline rate.Not everyone with CKD develops ESRD after a 10-year follow-up. Absolute annual eGFR decline rate can help clinicians to better predict the progression of CKD. Individuals with renal function decline rate over 3 ml/min/1.73 m2/year require intensive CKD care.
International Nuclear Information System (INIS)
Roh, Heui-Seol
2015-01-01
Chemical energy transfer mechanisms at finite temperature are explored by a chemical energy transfer theory which is capable of investigating various chemical mechanisms of non-equilibrium, quasi-equilibrium, and equilibrium. Gibbs energy fluxes are obtained as a function of chemical potential, time, and displacement. Diffusion, convection, internal convection, and internal equilibrium chemical energy fluxes are demonstrated. The theory reveals that there are chemical energy flux gaps and broken discrete symmetries at the activation chemical potential, time, and displacement. The statistical, thermodynamic theory is the unification of diffusion and internal convection chemical reactions which reduces to the non-equilibrium generalization beyond the quasi-equilibrium theories of migration and diffusion processes. The relationship between kinetic theories of chemical and electrochemical reactions is also explored. The theory is applied to explore non-equilibrium chemical reactions as an illustration. Three variable separation constants indicate particle number constants and play key roles in describing the distinct chemical reaction mechanisms. The kinetics of chemical energy transfer accounts for the four control mechanisms of chemical reactions such as activation, concentration, transition, and film chemical reactions. - Highlights: • Chemical energy transfer theory is proposed for non-, quasi-, and equilibrium. • Gibbs energy fluxes are expressed by chemical potential, time, and displacement. • Relationship between chemical and electrochemical reactions is discussed. • Theory is applied to explore nonequilibrium energy transfer in chemical reactions. • Kinetics of non-equilibrium chemical reactions shows the four control mechanisms
Fundamental functions in equilibrium thermodynamics
Horst, H.J. ter
In the standard presentations of the principles of Gibbsian equilibrium thermodynamics one can find several gaps in the logic. For a subject that is as widely used as equilibrium thermodynamics, it is of interest to clear up such questions of mathematical rigor. In this paper it is shown that using
A Multiperiod Equilibrium Pricing Model
Directory of Open Access Journals (Sweden)
Minsuk Kwak
2014-01-01
Full Text Available We propose an equilibrium pricing model in a dynamic multiperiod stochastic framework with uncertain income. There are one tradable risky asset (stock/commodity, one nontradable underlying (temperature, and also a contingent claim (weather derivative written on the tradable risky asset and the nontradable underlying in the market. The price of the contingent claim is priced in equilibrium by optimal strategies of representative agent and market clearing condition. The risk preferences are of exponential type with a stochastic coefficient of risk aversion. Both subgame perfect strategy and naive strategy are considered and the corresponding equilibrium prices are derived. From the numerical result we examine how the equilibrium prices vary in response to changes in model parameters and highlight the importance of our equilibrium pricing principle.
Non-equilibrium phase transitions
Henkel, Malte; Lübeck, Sven
2009-01-01
This book describes two main classes of non-equilibrium phase-transitions: (a) static and dynamics of transitions into an absorbing state, and (b) dynamical scaling in far-from-equilibrium relaxation behaviour and ageing. The first volume begins with an introductory chapter which recalls the main concepts of phase-transitions, set for the convenience of the reader in an equilibrium context. The extension to non-equilibrium systems is made by using directed percolation as the main paradigm of absorbing phase transitions and in view of the richness of the known results an entire chapter is devoted to it, including a discussion of recent experimental results. Scaling theories and a large set of both numerical and analytical methods for the study of non-equilibrium phase transitions are thoroughly discussed. The techniques used for directed percolation are then extended to other universality classes and many important results on model parameters are provided for easy reference.
Kanai, Takahiro; Shiizaki, Kazuhiro; Betsui, Hiroyuki; Aoyagi, Jun; Yamagata, Takanori
2018-05-16
Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary renal disorder. ADPKD is characterized clinically by the presence of multiple bilateral renal cysts that lead to chronic renal failure. The cysts evolve from renal tubular epithelial cells that express the Klotho gene. Notably, Klotho acts as a co-receptor for fibroblast growth factor 23 (FGF23); in this context, it induces phosphaturia and maintains serum phosphate at a normal level. Many reports have shown that decreases in the soluble Klotho level and increases in the FGF23 level are associated with glomerular filtration rate (GFR) decline, but a recent study observed these changes in patient with normal eGFR. It remains unclear whether the decrease in the Klotho level precedes the increase in FGF23. Here, we present an ADPKD patient with enlarged kidneys due to multiple cysts who had a decreased soluble Klotho level but a normal eGFR and a normal FGF23 level. The patient's serum phosphate level was normal, as was the fractional excretion of phosphate (FEP). This appears to be the first reported case to show a decreased soluble Klotho level plus normal eGFR, FGF23, and FEP. These results suggest that Klotho decreases before FGF23 increases and further suggest that Klotho is not required to maintain normal serum phosphate levels in ADPKD if the FEP and serum phosphate levels are normal.
Inker, Lesley A.; Lambers Heerspink, Hiddo J.; Mondal, Hasi; Schmid, Christopher H.; Tighiouart, Hocine; Noubary, Farzad; Coresh, Josef; Greene, Tom; Levey, Andrew S.
2014-01-01
Background: There is increased interest in using alternative end points for trials of kidney disease progression. The currently established end points of end-stage renal disease and doubling of serum creatinine level, equivalent to a 57% decline in estimated glomerular filtration rate (eGFR), are
Non-equilibrium supramolecular polymerization.
Sorrenti, Alessandro; Leira-Iglesias, Jorge; Markvoort, Albert J; de Greef, Tom F A; Hermans, Thomas M
2017-09-18
Supramolecular polymerization has been traditionally focused on the thermodynamic equilibrium state, where one-dimensional assemblies reside at the global minimum of the Gibbs free energy. The pathway and rate to reach the equilibrium state are irrelevant, and the resulting assemblies remain unchanged over time. In the past decade, the focus has shifted to kinetically trapped (non-dissipative non-equilibrium) structures that heavily depend on the method of preparation (i.e., pathway complexity), and where the assembly rates are of key importance. Kinetic models have greatly improved our understanding of competing pathways, and shown how to steer supramolecular polymerization in the desired direction (i.e., pathway selection). The most recent innovation in the field relies on energy or mass input that is dissipated to keep the system away from the thermodynamic equilibrium (or from other non-dissipative states). This tutorial review aims to provide the reader with a set of tools to identify different types of self-assembled states that have been explored so far. In particular, we aim to clarify the often unclear use of the term "non-equilibrium self-assembly" by subdividing systems into dissipative, and non-dissipative non-equilibrium states. Examples are given for each of the states, with a focus on non-dissipative non-equilibrium states found in one-dimensional supramolecular polymerization.
Spontaneity and Equilibrium: Why "?G Equilibrium" Are Incorrect
Raff, Lionel M.
2014-01-01
The fundamental criteria for chemical reactions to be spontaneous in a given direction are generally incorrectly stated as ?G equilibrium are also misstated as being ?G = 0 or ?A = 0. Following a brief review of the…
Miftari, Rame; Nura, Adem; Topçiu-Shufta, Valdete; Miftari, Valon; Murseli, Arbenita; Haxhibeqiri, Valdete
2017-01-01
Aim: The aim of this study was determination of validity of 99mTcDTPA estimation of GFR for early detection of chronic kidney failure Material and methods: There were 110 patients (54 males and 56 females) with kidney disease referred for evaluation of renal function at UCC of Kosovo. All patients were included in two groups. In the first group were included 30 patients confirmed with renal failure, whereas in the second group were included 80 patients with other renal disease. In study were included only patients with ready results of creatinine, urea and glucose in the blood serum. For estimation of GFR we have used the Gate GFR DTPA method. The statistical data processing was conducted using statistical methods such as arithmetic average, the student t-test, percentage or rate, sensitivity, specificity and accuracy of the test. Results: The average age of all patients was 36 years old. The average age of female was 37 whereas of male 35. Patients with renal failure was significantly older than patients with other renal disease (p<0.005). Renal failure was found in 30 patients (27.27%). The concentration of urea and creatinine in blood serum of patients with renal failure were significantly higher than in patients with other renal disease (P< 0.00001). GFR in patients with renal failure were significantly lower than in patients with other renal disease, 51.75 ml/min (p<0.00001). Sensitivity of uremia and creatininemia for detection of renal failure were 83.33%, whereas sensitivity of 99mTcDTPA GFR was 100%. Specificity of uraemia and creatininemia were 63% whereas specificity of 99mTcDTPA GFR was 47.5%. Diagnostic accuracy of blood urea and creatinine in detecting of renal failure were 69%, whereas diagnostic accuracy of 99mTcDTPA GFR was 61.8%. Conclusion: Gate 99mTc DTPA scintigraphy in collaboration with biochemical tests are very sensitive methods for early detection of patients with chronic renal failure. PMID:28883673
International Nuclear Information System (INIS)
Qamar, A.; Ahmad, T.M.; Hayat, A.; Khan, M.A.; Rehman, S. Z.
2017-01-01
To compare e-GFR estimated by creatinine or cystatin C based and combined creatinine and cystatin C based equations in type 2 diabetics in different stages of albuminuria. Study Design: Comparative cross-sectional study. Place and Duration of Study: Department of Chemical Pathology, Army Medical College Rawalpindi in collaboration with endocrinology outpatient department Military Hospital Rawalpindi, from Nov 2015 to Nov 2016. Material and Methods: A total of 119 type 2 diabetic subjects of either gender, aged 30- 60 years were enrolled in the study with duration of diabetes less than 15 years and were divided into further sub groups on the basis of degree of albuminuria determined by spot urine albumin to creatinine ratio (uACR). Fifty age matched disease free controls with no history of any systemic disease were also included in the study. Known patients of type 1 diabetes, chronic inflammatory disorders, uncontrolled hypertension, thyroid disease, chronic kidney disease, on lipid lowering drugs, steroids, ACE inhibitors and pregnant ladies were excluded from the study. Serum creatinine serum cystatin C were assessed on fully automated chemistry analyzer selectra. E-GFR was calculated by online GFR calculator by National Kidney Foundation. Comparison of means of e-GFR calculated by various equations was carried out by one way ANOVA and post-hoc Tukey tests. Degree of agreement between various equations for the estimation of GFR was assessed by kappa statistics. A p-value less than 0.05 were considered statistically significant. Results: Mean e-GFR (ml/min/1.73m2) was lowest in cystatin C based CKD-EPI equation (89.56 +- 39.84) followed by combined cystatin C and creatinine based CKD-EPI (92.34 +- 37.88). Values of e-GFR by creatinine based CKD-EPI equation (95.84 +- 27.24), and by creatinine based MDRD equation (105.37 +- 64.98) were both higher. In creatinine based MDRD, equation normo albuminuria and micro albuminuria groups did not show statistically
Helical axis stellarator equilibrium model
International Nuclear Information System (INIS)
Koniges, A.E.; Johnson, J.L.
1985-02-01
An asymptotic model is developed to study MHD equilibria in toroidal systems with a helical magnetic axis. Using a characteristic coordinate system based on the vacuum field lines, the equilibrium problem is reduced to a two-dimensional generalized partial differential equation of the Grad-Shafranov type. A stellarator-expansion free-boundary equilibrium code is modified to solve the helical-axis equations. The expansion model is used to predict the equilibrium properties of Asperators NP-3 and NP-4. Numerically determined flux surfaces, magnetic well, transform, and shear are presented. The equilibria show a toroidal Shafranov shift
International Nuclear Information System (INIS)
Ghafoor, S.; Ali, M.K.; Khan, G.
2014-01-01
To correlate Gates glomerular filtration rate (GGFR) using technetium-99m diethylene triaminepentacetic acid (99mTc DTPA) with 24-hour creatinine clearance (CRCL) and to establish relationship with duration of diabetes in patients with early diabetic nephropathy. Study Design: A cross-sectional comparative study carried out in Nuclear Medical Centre from Aug 2009 to Jan 2010 at Armed Forces Institute of Pathology (AFIP), Rawalpindi, Pakistan. Patients and Methods: A total of eighty three subjects were enrolled, who were divided into three groups; group 1 comprised 31 normotensive diabetics, group 2 had 37 hypertensive diabetics while group 3 had 15 normal subjects. The DTPA GFR and creatinine clearance in healthy subjects as well as diabetic patients were compared using the unpaired student's t-test. The linear association between GFR, creatinine clearance and disease duration was expressed by Pearson's correlation coefficient 'r' along with their significance levels. Results: Gates GFR showed hyperfiltration in normotensive diabetics (96.6 +- 3.3 ml/min/1.73 m/sub 2/), significantly (p<0.05) higher than controls (85.5 +- 5 ml/min/1.73 m/sub 2/), whereas hypertensive diabetics had a significantly lower (p<0.05) Gates GFR (76.8 +- 3.7) than that of controls. Significant degree of correlation existed between GGFR and CRCL in hypertensive diabetics (p<0.05, r=0.716) and controls (r=0.546). Gates GFR also showed good correlation with duration of diabetes in both diabetic groups as compared to that of CRCL. GGFR also correlated well with duration of hypertension 0.37 (0.31-0.43) as compared to CRCL 0.155 (0.15-0.16) in all groups. Conclusions: The 99mTc-DTPA clearance correlates significantly with 24-hour creatinine clearance as well as with disease duration and can provide a simple and convenient index of kidney function in patients of early diabetic nephropathy. (author)
Energy Technology Data Exchange (ETDEWEB)
Reyes R, R.; Martin del Campo M, C.; Francois L, J. L. [UNAM, Facultad de Ingenieria, Departamento de Sistemas Energeticos, Paseo Cuauhnahuac 8532, 62550 Jiutepec, Morelos (Mexico); Brun, E.; Dumonteil, E.; Malvagi, F., E-mail: emeric.brun@cea.fr [Commissariat a l' Energie Atomique et aux Energies Alternative, Service d' Etude des Reacteurs et de Mathematiques Appliquees, Saclay, DEN/DM2S/SERMA/LTSD, Bat 470, 91191 Gif-sur-Yvette Cedex (France)
2011-11-15
Burnt calculations were realized for a fuel model based on the technology of the Gas-cooled Fast Reactor, GFR. The fuel design is based on bars. The code MCNPX-CINDER90 and the CSADA method for the burnt calculations were used. Models of homogeneous and heterogeneous fuel assembly were studied; for the burnt calculations of the fuel homogeneous model was considered the tracking of three series (Tiers) of evolution of the fission products. The Tier 1 tracks a reduced group of fission products, the Tier 2 tracks to the arrangement of fission products that are contained in the library of cross sections XSDIR of MCNPX; and the Tier 3 tracks 1325 fission products. The results were compared with those obtained with Tripoli-4-D in function of the calculation methods: 1) Explicit Euler, as method of first order; and 2) CSADA, as method of second order. According to the results was observed that the infinite multiplication factor varies in function of the fission products quantity that are tracked. The calculation time used by MCNPX-C90 with the series Tier 3 is more than double than the used by Tripoli-4-D, therefore this last code has advantage over MCNPX-C90 in the case of neutrons analysis of fast reactors. (Author)
Numerical Verification Of Equilibrium Chemistry
International Nuclear Information System (INIS)
Piro, Markus; Lewis, Brent; Thompson, William T.; Simunovic, Srdjan; Besmann, Theodore M.
2010-01-01
A numerical tool is in an advanced state of development to compute the equilibrium compositions of phases and their proportions in multi-component systems of importance to the nuclear industry. The resulting software is being conceived for direct integration into large multi-physics fuel performance codes, particularly for providing boundary conditions in heat and mass transport modules. However, any numerical errors produced in equilibrium chemistry computations will be propagated in subsequent heat and mass transport calculations, thus falsely predicting nuclear fuel behaviour. The necessity for a reliable method to numerically verify chemical equilibrium computations is emphasized by the requirement to handle the very large number of elements necessary to capture the entire fission product inventory. A simple, reliable and comprehensive numerical verification method is presented which can be invoked by any equilibrium chemistry solver for quality assurance purposes.
Equilibrium ignition for ICF capsules
International Nuclear Information System (INIS)
Lackner, K.S.; Colgate, S.A.; Johnson, N.L.; Kirkpatrick, R.C.; Menikoff, R.; Petschek, A.G.
1993-01-01
There are two fundamentally different approaches to igniting DT fuel in an ICF capsule which can be described as equilibrium and hot spot ignition. In both cases, a capsule which can be thought of as a pusher containing the DT fuel is imploded until the fuel reaches ignition conditions. In comparing high-gain ICF targets using cryogenic DT for a pusher with equilibrium ignition targets using high-Z pushers which contain the radiation. The authors point to the intrinsic advantages of the latter. Equilibrium or volume ignition sacrifices high gain for lower losses, lower ignition temperature, lower implosion velocity and lower sensitivity of the more robust capsule to small fluctuations and asymmetries in the drive system. The reduction in gain is about a factor of 2.5, which is small enough to make the more robust equilibrium ignition an attractive alternative
On the local equilibrium condition
International Nuclear Information System (INIS)
Hessling, H.
1994-11-01
A physical system is in local equilibrium if it cannot be distinguished from a global equilibrium by ''infinitesimally localized measurements''. This should be a natural characterization of local equilibrium, but the problem is to give a precise meaning to the qualitative phrase ''infinitesimally localized measurements''. A solution is suggested in form of a Local Equilibrium Condition (LEC), which can be applied to linear relativistic quantum field theories but not directly to selfinteracting quantum fields. The concept of local temperature resulting from LEC is compared to an old approach to local temperature based on the principle of maximal entropy. It is shown that the principle of maximal entropy does not always lead to physical states if it is applied to relativistic quantum field theories. (orig.)
Directory of Open Access Journals (Sweden)
Gabriel J. Turbay
2011-03-01
Full Text Available The strategic equilibrium of an N-person cooperative game with transferable utility is a system composed of a cover collection of subsets of N and a set of extended imputations attainable through such equilibrium cover. The system describes a state of coalitional bargaining stability where every player has a bargaining alternative against any other player to support his corresponding equilibrium claim. Any coalition in the sable system may form and divide the characteristic value function of the coalition as prescribed by the equilibrium payoffs. If syndicates are allowed to form, a formed coalition may become a syndicate using the equilibrium payoffs as disagreement values in bargaining for a part of the complementary coalition incremental value to the grand coalition when formed. The emergent well known-constant sum derived game in partition function is described in terms of parameters that result from incumbent binding agreements. The strategic-equilibrium corresponding to the derived game gives an equal value claim to all players. This surprising result is alternatively explained in terms of strategic-equilibrium based possible outcomes by a sequence of bargaining stages that when the binding agreements are in the right sequential order, von Neumann and Morgenstern (vN-M non-discriminatory solutions emerge. In these solutions a preferred branch by a sufficient number of players is identified: the weaker players syndicate against the stronger player. This condition is referred to as the stronger player paradox. A strategic alternative available to the stronger players to overcome the anticipated not desirable results is to voluntarily lower his bargaining equilibrium claim. In doing the original strategic equilibrium is modified and vN-M discriminatory solutions may occur, but also a different stronger player may emerge that has eventually will have to lower his equilibrium claim. A sequence of such measures converges to the equal
Thermodynamic evolution far from equilibrium
Khantuleva, Tatiana A.
2018-05-01
The presented model of thermodynamic evolution of an open system far from equilibrium is based on the modern results of nonequilibrium statistical mechanics, the nonlocal theory of nonequilibrium transport developed by the author and the Speed Gradient principle introduced in the theory of adaptive control. Transition to a description of the system internal structure evolution at the mesoscopic level allows a new insight at the stability problem of non-equilibrium processes. The new model is used in a number of specific tasks.
Relevance of equilibrium in multifragmentation
International Nuclear Information System (INIS)
Furuta, Takuya; Ono, Akira
2009-01-01
The relevance of equilibrium in a multifragmentation reaction of very central 40 Ca + 40 Ca collisions at 35 MeV/nucleon is investigated by using simulations of antisymmetrized molecular dynamics (AMD). Two types of ensembles are compared. One is the reaction ensemble of the states at each reaction time t in collision events simulated by AMD, and the other is the equilibrium ensemble prepared by solving the AMD equation of motion for a many-nucleon system confined in a container for a long time. The comparison of the ensembles is performed for the fragment charge distribution and the excitation energies. Our calculations show that there exists an equilibrium ensemble that well reproduces the reaction ensemble at each reaction time t for the investigated period 80≤t≤300 fm/c. However, there are some other observables that show discrepancies between the reaction and equilibrium ensembles. These may be interpreted as dynamical effects in the reaction. The usual static equilibrium at each instant is not realized since any equilibrium ensemble with the same volume as that of the reaction system cannot reproduce the fragment observables
Shape characteristics of equilibrium and non-equilibrium fractal clusters.
Mansfield, Marc L; Douglas, Jack F
2013-07-28
It is often difficult in practice to discriminate between equilibrium and non-equilibrium nanoparticle or colloidal-particle clusters that form through aggregation in gas or solution phases. Scattering studies often permit the determination of an apparent fractal dimension, but both equilibrium and non-equilibrium clusters in three dimensions frequently have fractal dimensions near 2, so that it is often not possible to discriminate on the basis of this geometrical property. A survey of the anisotropy of a wide variety of polymeric structures (linear and ring random and self-avoiding random walks, percolation clusters, lattice animals, diffusion-limited aggregates, and Eden clusters) based on the principal components of both the radius of gyration and electric polarizability tensor indicates, perhaps counter-intuitively, that self-similar equilibrium clusters tend to be intrinsically anisotropic at all sizes, while non-equilibrium processes such as diffusion-limited aggregation or Eden growth tend to be isotropic in the large-mass limit, providing a potential means of discriminating these clusters experimentally if anisotropy could be determined along with the fractal dimension. Equilibrium polymer structures, such as flexible polymer chains, are normally self-similar due to the existence of only a single relevant length scale, and are thus anisotropic at all length scales, while non-equilibrium polymer structures that grow irreversibly in time eventually become isotropic if there is no difference in the average growth rates in different directions. There is apparently no proof of these general trends and little theoretical insight into what controls the universal anisotropy in equilibrium polymer structures of various kinds. This is an obvious topic of theoretical investigation, as well as a matter of practical interest. To address this general problem, we consider two experimentally accessible ratios, one between the hydrodynamic and gyration radii, the other
SPES, Fuel Cycle Optimization for LWR
International Nuclear Information System (INIS)
1973-01-01
1 - Nature of physical problem solved: Determination of optimal fuel cycle at equilibrium for a light water reactor taking into account batch size, fuel enrichment, de-rating, shutdown time, cost of replacement energy. 2 - Method of solution: Iterative method
Local Equilibrium and Retardation Revisited.
Hansen, Scott K; Vesselinov, Velimir V
2018-01-01
In modeling solute transport with mobile-immobile mass transfer (MIMT), it is common to use an advection-dispersion equation (ADE) with a retardation factor, or retarded ADE. This is commonly referred to as making the local equilibrium assumption (LEA). Assuming local equilibrium, Eulerian textbook treatments derive the retarded ADE, ostensibly exactly. However, other authors have presented rigorous mathematical derivations of the dispersive effect of MIMT, applicable even in the case of arbitrarily fast mass transfer. We resolve the apparent contradiction between these seemingly exact derivations by adopting a Lagrangian point of view. We show that local equilibrium constrains the expected time immobile, whereas the retarded ADE actually embeds a stronger, nonphysical, constraint: that all particles spend the same amount of every time increment immobile. Eulerian derivations of the retarded ADE thus silently commit the gambler's fallacy, leading them to ignore dispersion due to mass transfer that is correctly modeled by other approaches. We then present a particle tracking simulation illustrating how poor an approximation the retarded ADE may be, even when mobile and immobile plumes are continually near local equilibrium. We note that classic "LEA" (actually, retarded ADE validity) criteria test for insignificance of MIMT-driven dispersion relative to hydrodynamic dispersion, rather than for local equilibrium. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.
... Diabetes Diarrhea Disseminated Intravascular Coagulation (DIC) Down Syndrome Ebola Virus Infection Endocrine System and Syndromes Epilepsy Excessive ... See More See Less Related Images View More × Structure of a kidney. Image credit: Alan Hoofring, National ...
Non-equilibrium in flowing atmospheric plasmas
International Nuclear Information System (INIS)
Haas, J.C.M. de.
1986-01-01
This thesis deals with the fundamental aspects of two different plasmas applied in technological processes. The first one is the cesium seeded argon plasma in a closed cycle Magnetohydrodynamic (MHD) generator, the second is the thermal argon plasma in a cascade arc with an imposed flow. In Chapter 2 the influence of non-equilibrium on the mass and energy balances of a plasma is worked out. The general theory presented there can be applied to both the plasma in an MHD generator and to the cascade arc with imposed flow. Introductions to these plasmas are given in the Chapters 3 and 6 respectively. These chapters are both followed by two chapters which treat the theoretical and the experimental investigations. The results are summarized in Chapter 9. (Auth.)
Equilibrium Arrival Times to Queues
DEFF Research Database (Denmark)
Breinbjerg, Jesper; Østerdal, Lars Peter
We consider a non-cooperative queueing environment where a finite number of customers independently choose when to arrive at a queueing system that opens at a given point in time and serves customers on a last-come first-serve preemptive-resume (LCFS-PR) basis. Each customer has a service time...... requirement which is identically and independently distributed according to some general probability distribution, and they want to complete service as early as possible while minimizing the time spent in the queue. In this setting, we establish the existence of an arrival time strategy that constitutes...... a symmetric (mixed) Nash equilibrium, and show that there is at most one symmetric equilibrium. We provide a numerical method to compute this equilibrium and demonstrate by a numerical example that the social effciency can be lower than the effciency induced by a similar queueing system that serves customers...
DEFF Research Database (Denmark)
Therwani, Safa; Malmberg, My Emma Sofie; Rosenbaek, Jeppe Bakkestroem
2017-01-01
-dependent mechanism. U-AQP2 was not changed by tolvaptan, presumeably due to a counteracting effect of elevated p-AVP. The reduced GFR during tolvaptan most likely is caused by the reduction in extracellular fluid volume and blood pressure. Trial registration: Clinical Trial no: NCT02527863. Registered 18 February...... received tolvaptan 60 mg or placebo in a randomized, placebo-controlled, double blind, crossover study. L-NMMA (L-NG-monomethyl-arginine) was given as a bolus followed by continuous infusion during 60 min. We measured: GFR, urine output (UO), free water clearance (CH2O), fractional excretion of sodium...... (FENa), urinary excretion of aquaporin-2 channels (u-AQP2) and epithelial sodium channels (u-ENaCγ), plasma concentrations of vasopressin (p-AVP), renin (PRC), angiotensinII (p-AngII), aldosterone (p-Aldo), and central blood pressure (cBP). Results: During tolvaptan with NO-inhibition, a more pronounced...
Direct transition from a stable equilibrium to quasiperiodicity in non-smooth systems
DEFF Research Database (Denmark)
Zhusubaliyev, Z.T.; Mosekilde, Erik
2008-01-01
The purpose of this Letter is to show how a border-collision bifurcation in a piecewise-smooth dynamical system can produce a direct transition from a stable equilibrium point to a two-dimensional invariant torus. Considering a system of nonautonomous differential equations describing the behavior...... of a power electronic DC/DC converter, we first determine the chart of dynamical modes and show that there is a region of parameter space in which the system has a single stable equilibrium point. Under variation of the parameters, this equilibrium may collide with a discontinuity boundary between two smooth...... regions in phase space. When this happens, one can observe a number of different bifurcation scenarios. One scenario is the continuous transformation of the stable equilibrium into a stable period-1 cycle. Another is the transformation of the stable equilibrium into an unstable period-1 cycle with complex...
Spontaneity and Equilibrium: Why "?G Equilibrium" Are Incorrect
Raff, Lionel M.
2014-01-01
The fundamental criteria for chemical reactions to be spontaneous in a given direction are generally incorrectly stated as ?G chemistry textbooks and even in some more advanced texts. Similarly, the criteria for equilibrium are also misstated as being ?G = 0 or ?A = 0. Following a brief review of the…
Schmidt-Hieltjes, Yvonne; Elshof, Clemens; Roovers, Lian; Ruinemans-Koerts, Janneke
2016-05-01
The aim of our study was to analyse whether the κ/λ free light chain ratio reference range for screening for Bence Jones proteinuria should be dependent on the estimated glomerular filtration rate (eGFR). The serum κ/λ free light chain ratio, eGFR, serum M-protein and Bence Jones protein were measured in 544 patients for whom Bence Jones protein analysis was ordered. In the population of patients without Bence Jones proteinuria or a M-protein (n = 402), there is no gradual increase in κ/λ free light chain ratio with diminishing eGFR. The κ/λ free light chain ratio in this group was 0.56-1.86 (95% interval). With this diagnostic reference range of the κ/λ ratio, 105 of the 110 patients with Bence Jones protein could be identified correctly. Only five patients with Bence Jones proteinuria (free light chain ratio was measured without the presence of Bence Jones proteinuria. A κ/λ free light chain ratio in serum can be used safely and efficiently to select urine samples which should be analysed for Bence Jones proteinuria with an electrophoresis/immunofixation technique. Using this diagnostic reference range, the number of urine samples which should be analysed by electrophoresis/immunofixation could be reduced by 74%. The diagnostic reference interval can be determined best in a group of patients for whom Bence Jones analysis is indicated. For calculation of this reference range, the eGFR value does not need to be taken into account. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Equilibrium problems for Raney densities
Forrester, Peter J.; Liu, Dang-Zheng; Zinn-Justin, Paul
2015-07-01
The Raney numbers are a class of combinatorial numbers generalising the Fuss-Catalan numbers. They are indexed by a pair of positive real numbers (p, r) with p > 1 and 0 0 and similarly use both methods to identify the equilibrium problem for (p, r) = (θ/q + 1, 1/q), θ > 0 and q \\in Z+ . The Wiener-Hopf method is used to extend the latter to parameters (p, r) = (θ/q + 1, m + 1/q) for m a non-negative integer, and also to identify the equilibrium problem for a family of densities with moments given by certain binomial coefficients.
Equilibrium in a Production Economy
Energy Technology Data Exchange (ETDEWEB)
Chiarolla, Maria B., E-mail: maria.chiarolla@uniroma1.it [Universita di Roma ' La Sapienza' , Dipartimento di Metodi e Modelli per l' Economia, il Territorio e la Finanza, Facolta di Economia (Italy); Haussmann, Ulrich G., E-mail: uhaus@math.ubc.ca [University of British Columbia, Department of Mathematics (Canada)
2011-06-15
Consider a closed production-consumption economy with multiple agents and multiple resources. The resources are used to produce the consumption good. The agents derive utility from holding resources as well as consuming the good produced. They aim to maximize their utility while the manager of the production facility aims to maximize profits. With the aid of a representative agent (who has a multivariable utility function) it is shown that an Arrow-Debreu equilibrium exists. In so doing we establish technical results that will be used to solve the stochastic dynamic problem (a case with infinite dimensional commodity space so the General Equilibrium Theory does not apply) elsewhere.
Incentives in Supply Function Equilibrium
DEFF Research Database (Denmark)
Vetter, Henrik
2014-01-01
The author analyses delegation in homogenous duopoly under the assumption that the firm-managers compete in supply functions. In supply function equilibrium, managers’ decisions are strategic complements. This reverses earlier findings in that the author finds that owners give managers incentives...... to act in an accommodating way. As a result, optimal delegation reduces per-firm output and increases profits to above-Cournot profits. Moreover, in supply function equilibrium the mode of competition is endogenous. This means that the author avoids results that are sensitive with respect to assuming...
Equilibrium in a Production Economy
International Nuclear Information System (INIS)
Chiarolla, Maria B.; Haussmann, Ulrich G.
2011-01-01
Consider a closed production-consumption economy with multiple agents and multiple resources. The resources are used to produce the consumption good. The agents derive utility from holding resources as well as consuming the good produced. They aim to maximize their utility while the manager of the production facility aims to maximize profits. With the aid of a representative agent (who has a multivariable utility function) it is shown that an Arrow-Debreu equilibrium exists. In so doing we establish technical results that will be used to solve the stochastic dynamic problem (a case with infinite dimensional commodity space so the General Equilibrium Theory does not apply) elsewhere.
The Equilibrium Rule--A Personal Discovery
Hewitt, Paul G.
2016-01-01
Examples of equilibrium are evident everywhere and the equilibrium rule provides a reasoned way to view all things, whether in static (balancing rocks, steel beams in building construction) or dynamic (airplanes, bowling balls) equilibrium. Interestingly, the equilibrium rule applies not just to objects at rest but whenever any object or system of…
Non equilibrium atomic processes and plasma spectroscopy
International Nuclear Information System (INIS)
Kato, Takako
2003-01-01
Along with the technical progress in plasma spectroscopy, non equilibrium ionization processes have been recently observed. We study non local thermodynamic equilibrium and non ionization equilibrium for various kinds of plasmas. Specifically we discuss non equilibrium atomic processes in magnetically confined plasmas, solar flares and laser produced plasmas using a collisional radiative model based on plasma spectroscopic data. (author)
Potter, Julia M; Simpson, Aaron J; Kerrigan, Jennifer; Southcott, Emma; Salib, Marie M; Koerbin, Gus; Hickman, Peter E
2017-10-01
While persons with overt renal failure have a well-described rise in troponin and NT-proBNP, it is less well described what the relationship is between cardiac markers and persons with impaired renal function, not requiring dialysis. We have collected ALL samples referred to our pathology practice over a 24h period and measured hs-cTnI, hs-cTnT, NT-proBNP, calculated the eGFR, and related our measurements to clinical outcomes. For both men and women, for all of hs-cTnI, hs-cTnT and NT-proBNP, there was a graded response, as renal function worsened, the concentration of the cardiac marker increased. There is a graded inverse relationship between eGFR and the concentrations of hs-cTnI, hs-cTnT and NT-proBNP. For women only there appeared to be an increase in mortality at lowest eGFR. Copyright © 2017 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.
Fabre, Emmanuelle E; Raynaud-Simon, Agathe; Golmard, Jean-Louis; Gourgouillon, Nadège; Beaudeux, Jean-Louis; Nivet-Antoine, Valérie
2010-01-01
Renal function is often altered in elderly patients. A lot of formulae are proposed to estimate GFR to adjust drug posology. French guidelines recommend the Cockcroft-Gault formula corrected with the body surface area (cCG), but the initially described unadjusted Cockcroft-Gault equation (CG) is mainly used in geriatric clinical practice. International recommendations have proposed the modification of diet in renal disease (MDRD) formula, since several authors recommended the Rule formula using cystatin C (cystC) in particular population. To appreciate the most accurate GFR estimation for posology adaptation in an elderly polypathological population, a cross-sectional study with prospective inclusion was carried out in Charles Foix Hospital. Plasma glucose levels (PGL), creatinine (CREA) levels and serum cystC, albumin (ALB), transthyretin (TTR), C-reactive protein (CRP), orosomucoid (ORO) total cholesterol (tCHOL) levels were determined among 193 elderly patients aged 70 and older. The results showed that in a malnourished, inflamed old population, CG, MDRD and Rule formulae resulted in different estimations of GFR, depending on nutritional and inflammatory parameters. Only cCG estimation was shown to be independent from these parameters. To conclude, cCG seems to be the most accurate and appropriate formula in a polypathological elderly population to evaluate renal function in order to adapt drug posology. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.
Business Cycle Theory and Econometrics.
Gregory, Allan W; Smith, Gregor W
1995-01-01
We outline in turn criticisms made by econometricians of the methods used in empirical business-cycle research and then criticisms made by business-cycle researchers of some methods used by econometricians. The aim is to clarify and in some cases correct these criticisms. Overall there is no conflict in using rigourous statistical procedures to study modern dynamic stochastic general equilibrium models. We also provide a concise bibliography of recent research on statistical methods for busin...
Advertising and Business Cycle Fluctuations
Benedetto Molinari; Francesco Turino
2009-01-01
This paper provides new empirical evidence of quarterly U.S. aggregate advertising expenditures, showing that advertising has a well defined pattern over the Business Cycle. To understand this pattern we develop a general equilibrium model where targeted advertising increases the marginal utility of the advertised good. Advertising intensity is endogenously determined by profit maximizing firms. We embed this assumption into an otherwise standard model of business cycle with monopolistic comp...
Deviations from thermal equilibrium in plasmas
International Nuclear Information System (INIS)
Burm, K.T.A.L.
2004-01-01
A plasma system in local thermal equilibrium can usually be described with only two parameters. To describe deviations from equilibrium two extra parameters are needed. However, it will be shown that deviations from temperature equilibrium and deviations from Saha equilibrium depend on one another. As a result, non-equilibrium plasmas can be described with three parameters. This reduction in parameter space will ease the plasma describing effort enormously
Non-equilibrium fluctuation-induced interactions
International Nuclear Information System (INIS)
Dean, David S
2012-01-01
We discuss non-equilibrium aspects of fluctuation-induced interactions. While the equilibrium behavior of such interactions has been extensively studied and is relatively well understood, the study of these interactions out of equilibrium is relatively new. We discuss recent results on the non-equilibrium behavior of systems whose dynamics is of the dissipative stochastic type and identify a number of outstanding problems concerning non-equilibrium fluctuation-induced interactions.
Initial and transition cycle development for KALIMER uranium fueled core
International Nuclear Information System (INIS)
Kim, Sang Ji; Kim, Young In; Kim, Young Jin; Park, Chang Kue
1998-01-01
An economic and safe equilibrium Uranium metallic fuelled core having been established, strategic loading schemes for initial and transition cycles to early reach target equilibrium cycles are suggested for U-U and U-Pu transition cycles. An iterative method to find initial core enrichment splits is developed. With non-uniform feed enrichments at the initial core adopted, this iterative method shows KALIMER can reach Uranium equilibrium cycles just after 4 reloads, keeping feed enrichment unchanged from cycle 2. Recycling of self-generated Pu is not sufficient to make KALIMER a pure Pu equilibrium core even after 56 reloads. equilibrium cycles are suggested for U-U and U-Pu transition cycles. An iterative method to find initial core enrichment splits is developed. With non-uniform feed enrichments at the initial core adopted, this iterative method shows KALIMER can reach Uranium equilibrium cycles just after 4 reloads, keeping feed enrichment unchanged from cycle 2. Recycling of self-generated Pu is not sufficient to make KALIMER a pure Pu equilibrium core even after 56 reloads
Understanding Thermal Equilibrium through Activities
Pathare, Shirish; Huli, Saurabhee; Nachane, Madhura; Ladage, Savita; Pradhan, Hemachandra
2015-01-01
Thermal equilibrium is a basic concept in thermodynamics. In India, this concept is generally introduced at the first year of undergraduate education in physics and chemistry. In our earlier studies (Pathare and Pradhan 2011 "Proc. episteme-4 Int. Conf. to Review Research on Science Technology and Mathematics Education" pp 169-72) we…
Thermodynamic theory of equilibrium fluctuations
International Nuclear Information System (INIS)
Mishin, Y.
2015-01-01
The postulational basis of classical thermodynamics has been expanded to incorporate equilibrium fluctuations. The main additional elements of the proposed thermodynamic theory are the concept of quasi-equilibrium states, a definition of non-equilibrium entropy, a fundamental equation of state in the entropy representation, and a fluctuation postulate describing the probability distribution of macroscopic parameters of an isolated system. Although these elements introduce a statistical component that does not exist in classical thermodynamics, the logical structure of the theory is different from that of statistical mechanics and represents an expanded version of thermodynamics. Based on this theory, we present a regular procedure for calculations of equilibrium fluctuations of extensive parameters, intensive parameters and densities in systems with any number of fluctuating parameters. The proposed fluctuation formalism is demonstrated by four applications: (1) derivation of the complete set of fluctuation relations for a simple fluid in three different ensembles; (2) fluctuations in finite-reservoir systems interpolating between the canonical and micro-canonical ensembles; (3) derivation of fluctuation relations for excess properties of grain boundaries in binary solid solutions, and (4) derivation of the grain boundary width distribution for pre-melted grain boundaries in alloys. The last two applications offer an efficient fluctuation-based approach to calculations of interface excess properties and extraction of the disjoining potential in pre-melted grain boundaries. Possible future extensions of the theory are outlined.
Equilibrium theory : A salient approach
Schalk, S.
1999-01-01
Whereas the neoclassical models in General Equilibrium Theory focus on the existence of separate commodities, this thesis regards 'bundles of trade' as the unit objects of exchange. Apart from commodities and commodity bundles in the neoclassical sense, the term `bundle of trade' includes, for
Essays in general equilibrium theory
Konovalov, A.
2001-01-01
The thesis focuses on various issues of general equilibrium theory and can approximately be divided into three parts. The first part of the thesis studies generalized equilibria in the Arrow-Debreu model in the situation where the strong survival assumption is not satisfied. Chapter four deals with
Financial equilibrium with career concerns
Directory of Open Access Journals (Sweden)
Amil Dasgupta
2006-03-01
Full Text Available What are the equilibrium features of a financial market where a sizeable proportion of traders face reputational concerns? This question is central to our understanding of financial markets, which are increasingly dominated by institutional investors. We construct a model of delegated portfolio management that captures key features of the US mutual fund industry and embed it in an asset pricing framework. We thus provide a formal model of financial equilibrium with career concerned agents. Fund managers differ in their ability to understand market fundamentals, and in every period investors choose a fund. In equilibrium, the presence of career concerns induces uninformed fund managers to churn, i.e., to engage in trading even when they face a negative expected return. Churners act as noise traders and enhance the level of trading volume. The equilibrium relationship between fund return and net fund flows displays a skewed shape that is consistent with stylized facts. The robustness of our core results is probed from several angles.
Equilibrium with arbitrary market structure
DEFF Research Database (Denmark)
Grodal, Birgit; Vind, Karl
2005-01-01
. The complete market predicted by this theory is clearly unrealistic, and Radner [10] formulated and proved existence of equilibrium in a multiperiod model with incomplete markets. In this paper the Radner result is extended. Radner assumed a specific structure of markets, independence of preferences...
Nash equilibrium with lower probabilities
DEFF Research Database (Denmark)
Groes, Ebbe; Jacobsen, Hans Jørgen; Sloth, Birgitte
1998-01-01
We generalize the concept of Nash equilibrium in mixed strategies for strategic form games to allow for ambiguity in the players' expectations. In contrast to other contributions, we model ambiguity by means of so-called lower probability measures or belief functions, which makes it possible...
Allotropic transformation bcc in equilibrium hcp in zirconium
International Nuclear Information System (INIS)
Akhtar, A.
1976-01-01
The allotropic transformation hcp(α) in equilibrium bcc(β) was examined in crystal bar zirconium. The β → α transformation is massive type in melt grown crystals of β--Zr. Upon thermal cycling through α → β → α the bcc → hcp transformation occurs frequently through a shear process and less frequently through a massive transformation. The presence of α → β transformation substructure may favor the operation of the shear mode. The hcp → bcc phase change occurs through a massive transformation. A lack of transformation memory is associated with the process of thermal cycling. 11 fig., 3 tables
On generalized operator quasi-equilibrium problems
Kum, Sangho; Kim, Won Kyu
2008-09-01
In this paper, we will introduce the generalized operator equilibrium problem and generalized operator quasi-equilibrium problem which generalize the operator equilibrium problem due to Kazmi and Raouf [K.R. Kazmi, A. Raouf, A class of operator equilibrium problems, J. Math. Anal. Appl. 308 (2005) 554-564] into multi-valued and quasi-equilibrium problems. Using a Fan-Browder type fixed point theorem in [S. Park, Foundations of the KKM theory via coincidences of composites of upper semicontinuous maps, J. Korean Math. Soc. 31 (1994) 493-519] and an existence theorem of equilibrium for 1-person game in [X.-P. Ding, W.K. Kim, K.-K. Tan, Equilibria of non-compact generalized games with L*-majorized preferences, J. Math. Anal. Appl. 164 (1992) 508-517] as basic tools, we prove new existence theorems on generalized operator equilibrium problem and generalized operator quasi-equilibrium problem which includes operator equilibrium problems.
Non-Equilibrium Properties from Equilibrium Free Energy Calculations
Pohorille, Andrew; Wilson, Michael A.
2012-01-01
Calculating free energy in computer simulations is of central importance in statistical mechanics of condensed media and its applications to chemistry and biology not only because it is the most comprehensive and informative quantity that characterizes the eqUilibrium state, but also because it often provides an efficient route to access dynamic and kinetic properties of a system. Most of applications of equilibrium free energy calculations to non-equilibrium processes rely on a description in which a molecule or an ion diffuses in the potential of mean force. In general case this description is a simplification, but it might be satisfactorily accurate in many instances of practical interest. This hypothesis has been tested in the example of the electrodiffusion equation . Conductance of model ion channels has been calculated directly through counting the number of ion crossing events observed during long molecular dynamics simulations and has been compared with the conductance obtained from solving the generalized Nernst-Plank equation. It has been shown that under relatively modest conditions the agreement between these two approaches is excellent, thus demonstrating the assumptions underlying the diffusion equation are fulfilled. Under these conditions the electrodiffusion equation provides an efficient approach to calculating the full voltage-current dependence routinely measured in electrophysiological experiments.
Equilibrium studies of helical axis stellarators
International Nuclear Information System (INIS)
Hender, T.C.; Carreras, B.A.; Garcia, L.; Harris, J.H.; Rome, J.A.; Cantrell, J.L.; Lynch, V.E.
1984-01-01
The equilibrium properties of helical axis stellarators are studied with a 3-D equilibrium code and with an average method (2-D). The helical axis ATF is shown to have a toroidally dominated equilibrium shift and good equilibria up to at least 10% peak beta. Low aspect ratio heliacs, with relatively large toroidal shifts, are shown to have low equilibrium beta limits (approx. 5%). Increasing the aspect ratio and number of field periods proportionally is found to improve the equilibrium beta limit. Alternatively, increasing the number of field periods at fixed aspect ratio which raises and lowers the toroidal shift improves the equilibrium beta limit
Students’ misconceptions on solubility equilibrium
Setiowati, H.; Utomo, S. B.; Ashadi
2018-05-01
This study investigated the students’ misconceptions of the solubility equilibrium. The participants of the study consisted of 164 students who were in the science class of second year high school. Instrument used is two-tier diagnostic test consisting of 15 items. Responses were marked and coded into four categories: understanding, misconception, understand little without misconception, and not understanding. Semi-structured interviews were carried out with 45 students according to their written responses which reflected different perspectives, to obtain a more elaborated source of data. Data collected from multiple methods were analyzed qualitatively and quantitatively. Based on the data analysis showed that the students misconceptions in all areas in solubility equilibrium. They had more misconceptions such as in the relation of solubility and solubility product, common-ion effect and pH in solubility, and precipitation concept.
Fuel cycle studies for the Dragon HTR
Energy Technology Data Exchange (ETDEWEB)
Desoisa, J A; Nunn, R M; Twitchin, A E
1971-02-15
This note reports the progress made at B.N.L. in the study of the fuel cycle for the HTR design described by Daub (1970). The primary purpose of the study is to examine the special problems of the approach to equilibrium fuel cycle.
An introduction to equilibrium thermodynamics
Morrill, Bernard; Hartnett, James P; Hughes, William F
1973-01-01
An Introduction to Equilibrium Thermodynamics discusses classical thermodynamics and irreversible thermodynamics. It introduces the laws of thermodynamics and the connection between statistical concepts and observable macroscopic properties of a thermodynamic system. Chapter 1 discusses the first law of thermodynamics while Chapters 2 through 4 deal with statistical concepts. The succeeding chapters describe the link between entropy and the reversible heat process concept of entropy; the second law of thermodynamics; Legendre transformations and Jacobian algebra. Finally, Chapter 10 provides a
Money Inventories in Search Equilibrium
Berentsen, Aleksander
1998-01-01
The paper relaxes the one unit storage capacity imposed in the basic search-theoretic model of fiat money with indivisible real commodities and indivisible money. Agents can accumulate as much money as they want. It characterizes the stationary distributions of money and shows that for reasonable parameter values (e.g. production cost, discounting, degree of specialization) a monetary equilibrium exists. There are multiple stationary distributions of a given amount of money, which differ in t...
Local equilibrium in bird flocks
Mora, Thierry; Walczak, Aleksandra M.; Del Castello, Lorenzo; Ginelli, Francesco; Melillo, Stefania; Parisi, Leonardo; Viale, Massimiliano; Cavagna, Andrea; Giardina, Irene
2016-12-01
The correlated motion of flocks is an example of global order emerging from local interactions. An essential difference with respect to analogous ferromagnetic systems is that flocks are active: animals move relative to each other, dynamically rearranging their interaction network. This non-equilibrium characteristic has been studied theoretically, but its impact on actual animal groups remains to be fully explored experimentally. Here, we introduce a novel dynamical inference technique, based on the principle of maximum entropy, which accommodates network rearrangements and overcomes the problem of slow experimental sampling rates. We use this method to infer the strength and range of alignment forces from data of starling flocks. We find that local bird alignment occurs on a much faster timescale than neighbour rearrangement. Accordingly, equilibrium inference, which assumes a fixed interaction network, gives results consistent with dynamical inference. We conclude that bird orientations are in a state of local quasi-equilibrium over the interaction length scale, providing firm ground for the applicability of statistical physics in certain active systems.
Solvent Isotope-induced Equilibrium Perturbation for Isocitrate Lyase
Quartararo, Christine E.; Hadi, Timin; Cahill, Sean M.; Blanchard, John S.
2014-01-01
Isocitrate lyase (ICL) catalyzes the reversible retro-aldol cleavage of isocitrate to generate glyoxylate and succinate. ICL is the first enzyme of the glyoxylate shunt, which allows for the anaplerosis of citric acid cycle intermediates under nutrient limiting conditions. In Mycobacterium tuberculosis, the source of ICL for these studies, ICL is vital for the persistence phase of the bacteria’s life cycle. Solvent kinetic isotope effects (KIEs) in the direction of isocitrate cleavage of D2OV = 2.0 ± 0.1 and D2O[V/Kisocitrate] = 2.2 ± 0.3 arise from the initial deprotonation of the C2 hydroxyl group of isocitrate or the protonation of the aci-acid of succinate product of the isocitrate aldol cleavage by a solvent-derived proton. This KIE suggested that an equilibrium mixture of all protiated isocitrate, glyoxylate and succinate prepared in D2O, would undergo transient changes in equilibrium concentrations as a result of the solvent KIE and solvent-derived deuterium incorporation into both succinate and isocitrate. No change in the isotopic composition of glyoxylate was expected or observed. We have directly monitored the changing concentrations of all isotopic species of all reactants and products using a combination of NMR spectroscopy and mass spectrometry. Continuous monitoring of glyoxylate by 1H NMR spectroscopy shows a clear equilibrium perturbation in D2O. The final equilibrium isotopic composition of reactants in D2O revealed di-deuterated succinate, protiated glyoxylate, and mono-deuterated isocitrate, with the transient appearance and disappearance of mono-deuterated succinate. A model for the equilibrium perturbation of substrate species, and their time-dependent isotopic composition is presented. PMID:24261638
Quantum dynamical semigroups and approach to equilibrium
International Nuclear Information System (INIS)
Frigerio, A.
1977-01-01
For a quantum dynamical semigroup possessing a faithful normal stationary state, some conditions are discussed, which ensure the uniqueness of the equilibrium state and/or the approach to equilibrium for arbitrary initial condition. (Auth.)
The geometry of finite equilibrium sets
DEFF Research Database (Denmark)
Balasko, Yves; Tvede, Mich
2009-01-01
We investigate the geometry of finite datasets defined by equilibrium prices, income distributions, and total resources. We show that the equilibrium condition imposes no restrictions if total resources are collinear, a property that is robust to small perturbations. We also show that the set...... of equilibrium datasets is pathconnected when the equilibrium condition does impose restrictions on datasets, as for example when total resources are widely noncollinear....
Accelerating Multiagent Reinforcement Learning by Equilibrium Transfer.
Hu, Yujing; Gao, Yang; An, Bo
2015-07-01
An important approach in multiagent reinforcement learning (MARL) is equilibrium-based MARL, which adopts equilibrium solution concepts in game theory and requires agents to play equilibrium strategies at each state. However, most existing equilibrium-based MARL algorithms cannot scale due to a large number of computationally expensive equilibrium computations (e.g., computing Nash equilibria is PPAD-hard) during learning. For the first time, this paper finds that during the learning process of equilibrium-based MARL, the one-shot games corresponding to each state's successive visits often have the same or similar equilibria (for some states more than 90% of games corresponding to successive visits have similar equilibria). Inspired by this observation, this paper proposes to use equilibrium transfer to accelerate equilibrium-based MARL. The key idea of equilibrium transfer is to reuse previously computed equilibria when each agent has a small incentive to deviate. By introducing transfer loss and transfer condition, a novel framework called equilibrium transfer-based MARL is proposed. We prove that although equilibrium transfer brings transfer loss, equilibrium-based MARL algorithms can still converge to an equilibrium policy under certain assumptions. Experimental results in widely used benchmarks (e.g., grid world game, soccer game, and wall game) show that the proposed framework: 1) not only significantly accelerates equilibrium-based MARL (up to 96.7% reduction in learning time), but also achieves higher average rewards than algorithms without equilibrium transfer and 2) scales significantly better than algorithms without equilibrium transfer when the state/action space grows and the number of agents increases.
The Geometry of Finite Equilibrium Datasets
DEFF Research Database (Denmark)
Balasko, Yves; Tvede, Mich
We investigate the geometry of finite datasets defined by equilibrium prices, income distributions, and total resources. We show that the equilibrium condition imposes no restrictions if total resources are collinear, a property that is robust to small perturbations. We also show that the set...... of equilibrium datasets is pathconnected when the equilibrium condition does impose restrictions on datasets, as for example when total resources are widely non collinear....
International Nuclear Information System (INIS)
Lee, J. K.; Naganuma, M.
2006-01-01
Gas cooled Fast Reactor (GFR) is being researched as a candidate concept of Generation IV international Forum. As a main feature of GFR, it should be maintained high temperature and pressure of coolant gas for heat transfer efficiency. Such a demanding environment requires high-temperature-resistant structural materials distinguished from traditional steel material. Consequently, ceramics are promising candidate material of core components. Especially, Silicon Carbide fiber reinforced Silicon Carbide composites (SiC/SiC) have encouraging characteristics such as refractoriness, low activation and toughness. Application of new material to core components must be explained by the viewpoint of engineering validity. Therefore, present study surveyed that current report for mechanical strength and thermal conductivity of SiC/SiC composites. According to the reports, neutron irradiation environment degraded mechanical properties of SiC/SiC composites. To confirm applicability to core components, model of fuel pin using SiC/SiC composites was assumed with feasible mechanical properties. Furthermore, it was calculated and estimated that the stress caused by temperature variation of inner and outer side of assumed model of cladding tube. Stress was calculated by changing of input date such as thickness of cladding tube, temperature variation, thermal conductivity and linear power. In the range of this study, the most important factor was identified as degradation of thermal conductivity by irradiation. It caused a significant stress and limited a geometrical design of fuel pin. It was discussed that the differences of heat transfer between isotropic and anisotropic materials like a metal and composites. These results should be helpful not only to determine a design factor of core component but also to indicate an improvement direction of SiC/SiC composites. Through these work, reliability and safety of GFR will be increased
Miftari, Rame; Nura, Adem; Top?iu-Shufta, Valdete; Miftari, Valon; Murseli, Arbenita; Haxhibeqiri, Valdete
2017-01-01
Aim: The aim of this study was determination of validity of 99mTcDTPA estimation of GFR for early detection of chronic kidney failure Material and methods: There were 110 patients (54 males and 56 females) with kidney disease referred for evaluation of renal function at UCC of Kosovo. All patients were included in two groups. In the first group were included 30 patients confirmed with renal failure, whereas in the second group were included 80 patients with other renal disease. In study were ...
Open problems in non-equilibrium physics
International Nuclear Information System (INIS)
Kusnezov, D.
1997-01-01
The report contains viewgraphs on the following: approaches to non-equilibrium statistical mechanics; classical and quantum processes in chaotic environments; classical fields in non-equilibrium situations: real time dynamics at finite temperature; and phase transitions in non-equilibrium conditions
The concept of equilibrium in organization theory
Gazendam, H.W.M.
1998-01-01
Many organization theories consist of an interpretation frame and an idea about the ideal equilibrium state. This article explains how the equilibrium concept is used in four organization theories: the theories of Fayol, Mintzberg, Morgan, and Volberda. Equilibrium can be defined as balance, fit or
The concept of equilibrium in organization theory
Gazendam, Henk W.M.
1997-01-01
Many organization theories consist of an interpretation frame and an idea about the ideal equilibrium state. This article explains how the equilibrium concept is used in four organization theories: the theories of Fayol, Mintzberg, Morgan, and Volberda. Equilibrium can be defined as balance, fit or
Open problems in non-equilibrium physics
Energy Technology Data Exchange (ETDEWEB)
Kusnezov, D.
1997-09-22
The report contains viewgraphs on the following: approaches to non-equilibrium statistical mechanics; classical and quantum processes in chaotic environments; classical fields in non-equilibrium situations: real time dynamics at finite temperature; and phase transitions in non-equilibrium conditions.
Dotov, D G; Kim, S; Frank, T D
2015-02-01
We derive explicit expressions for the non-equilibrium thermodynamical variables of a canonical-dissipative limit cycle oscillator describing rhythmic motion patterns of active systems. These variables are statistical entropy, non-equilibrium internal energy, and non-equilibrium free energy. In particular, the expression for the non-equilibrium free energy is derived as a function of a suitable control parameter. The control parameter determines the Hopf bifurcation point of the deterministic active system and describes the effective pumping of the oscillator. In analogy to the equilibrium free energy of the Landau theory, it is shown that the non-equilibrium free energy decays as a function of the control parameter. In doing so, a similarity between certain equilibrium and non-equilibrium phase transitions is pointed out. Data from an experiment on human rhythmic movements is presented. Estimates for pumping intensity as well as the thermodynamical variables are reported. It is shown that in the experiment the non-equilibrium free energy decayed when pumping intensity was increased, which is consistent with the theory. Moreover, pumping intensities close to zero could be observed at relatively slow intended rhythmic movements. In view of the Hopf bifurcation underlying the limit cycle oscillator model, this observation suggests that the intended limit cycle movements were actually more similar to trajectories of a randomly perturbed stable focus. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
Equilibrium and non-equilibrium metal-ceramic interfaces
International Nuclear Information System (INIS)
Gao, Y.; Merkle, K.L.
1992-01-01
Metal-ceramic interfaces in thermodynamic equilibrium (Au/ZrO 2 ) and non-equilibrium (Au/MgO) have been studied by TEM and HREM. In the Au/ZrO 2 system, ZrO 2 precipitates formed by internal oxidation of a 7%Zr-Au alloy show a cubic ZrO 2 phase. It appears that formation of the cubic ZrO 2 is facilitated by alignment with the Au matrix. Most of the ZrO 2 precipitates have a perfect cube-on-cube orientation relationship with the Au matrix. The large number of interfacial steps observed in a short-time annealing experiment indicate that the precipitates are formed by the ledge growth mechanism. The lowest interfacial energy is indicated by the dominance of closed-packed [111] Au/ZrO 2 interfaces. In the Au/MgO system, composite films with small MgO smoke particles embedded in a Au matrix were prepared by a thin film technique. HREM observations show that most of the Au/MgO interfaces have a strong tendency to maintain a dense lattice structure across the interfaces irrespective of whether the interfaces are incoherent or semi-coherent. This paper reports that this indicates that there may be a relatively strong bond between MgO and Au
Thermal equilibrium in Einstein's elevator.
Sánchez-Rey, Bernardo; Chacón-Acosta, Guillermo; Dagdug, Leonardo; Cubero, David
2013-05-01
We report fully relativistic molecular-dynamics simulations that verify the appearance of thermal equilibrium of a classical gas inside a uniformly accelerated container. The numerical experiments confirm that the local momentum distribution in this system is very well approximated by the Jüttner function-originally derived for a flat spacetime-via the Tolman-Ehrenfest effect. Moreover, it is shown that when the acceleration or the container size is large enough, the global momentum distribution can be described by the so-called modified Jüttner function, which was initially proposed as an alternative to the Jüttner function.
Silverberg, Lee J.; Raff, Lionel M.
2015-01-01
Thermodynamic spontaneity-equilibrium criteria require that in a single-reaction system, reactions in either the forward or reverse direction at equilibrium be nonspontaneous. Conversely, the concept of dynamic equilibrium holds that forward and reverse reactions both occur at equal rates at equilibrium to the extent allowed by kinetic…
Approach to transverse equilibrium in axial channeling
International Nuclear Information System (INIS)
Fearick, R.W.
2000-01-01
Analytical treatments of channeling rely on the assumption of equilibrium on the transverse energy shell. The approach to equilibrium, and the nature of the equilibrium achieved, is examined using solutions of the equations of motion in the continuum multi-string model. The results show that the motion is chaotic in the absence of dissipative processes, and a complicated structure develops in phase space which prevent the development of the simple equilibrium usually assumed. The role of multiple scattering in smoothing out the equilibrium distribution is investigated
Fuel cycle optimization in PWR'S
International Nuclear Information System (INIS)
Castro Lobo, P.D. de; Amorim, E.S. do.
1979-08-01
Neutronics aspects of a reactor core throughout its cycle were investigated in a search for increasing in-core utilization of the residual fissile isotopes content in the cycle discharged disposal. The effects due to design modifications introduced at burnup levels near the end-of-cycle, in an equilibrium cycle condition, have indicated the possibility of a better in-core utilization of the residual fissile isotopes existing in the cycle discharged disposal. The potential benefits are significant to warranty an examination of the mechanical and thermal hydraulic involved. At convenient burnup levels, change in H 2 O/UO 2 volume ratio were introduced allowing an intense depletion of the residual fissile isotopes existing in assemblies with high exposures levels. (Author) [pt
Pre-equilibrium plasma dynamics
Energy Technology Data Exchange (ETDEWEB)
Heinz, U.
1986-01-01
Approaches towards understanding and describing the pre-equilibrium stage of quark-gluon plasma formation in heavy-ion collisions are reviewed. Focus is on a kinetic theory approach to non-equilibrium dynamics, its extension to include the dynamics of color degrees of freedom when applied to the quark-gluon plasma, its quantum field theoretical foundations, and its relationship to both the particle formation stage at the very beginning of the nuclear collision and the hydrodynamic stage at late collision times. The usefulness of this approach to obtain the transport coefficients in the quark-gluon plasma and to derive the collective mode spectrum and damping rates in this phase are discussed. Comments are made on the general difficulty to find appropriated initial conditions to get the kinetic theory started, and a specific model is given that demonstrates that, once given such initial conditions, the system can be followed all the way through into the hydrodynamical regime. 39 refs., 7 figs. (LEW)
Non-equilibrium phase transition
International Nuclear Information System (INIS)
Mottola, E.; Cooper, F.M.; Bishop, A.R.; Habib, S.; Kluger, Y.; Jensen, N.G.
1998-01-01
This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Non-equilibrium phase transitions play a central role in a very broad range of scientific areas, ranging from nuclear, particle, and astrophysics to condensed matter physics and the material and biological sciences. The aim of this project was to explore the path to a deeper and more fundamental understanding of the common physical principles underlying the complex real time dynamics of phase transitions. The main emphasis was on the development of general theoretical tools to deal with non-equilibrium processes, and of numerical methods robust enough to capture the time-evolving structures that occur in actual experimental situations. Specific applications to Laboratory multidivisional efforts in relativistic heavy-ion physics (transition to a new phase of nuclear matter consisting of a quark-gluon plasma) and layered high-temperature superconductors (critical currents and flux flow at the National High Magnetic Field Laboratory) were undertaken
Pre-equilibrium plasma dynamics
International Nuclear Information System (INIS)
Heinz, U.
1986-01-01
Approaches towards understanding and describing the pre-equilibrium stage of quark-gluon plasma formation in heavy-ion collisions are reviewed. Focus is on a kinetic theory approach to non-equilibrium dynamics, its extension to include the dynamics of color degrees of freedom when applied to the quark-gluon plasma, its quantum field theoretical foundations, and its relationship to both the particle formation stage at the very beginning of the nuclear collision and the hydrodynamic stage at late collision times. The usefulness of this approach to obtain the transport coefficients in the quark-gluon plasma and to derive the collective mode spectrum and damping rates in this phase are discussed. Comments are made on the general difficulty to find appropriated initial conditions to get the kinetic theory started, and a specific model is given that demonstrates that, once given such initial conditions, the system can be followed all the way through into the hydrodynamical regime. 39 refs., 7 figs
Equilibrium: two-dimensional configurations
International Nuclear Information System (INIS)
Anon.
1987-01-01
In Chapter 6, the problem of toroidal force balance is addressed in the simplest, nontrivial two-dimensional geometry, that of an axisymmetric torus. A derivation is presented of the Grad-Shafranov equation, the basic equation describing axisymmetric toroidal equilibrium. The solutions to equations provide a complete description of ideal MHD equilibria: radial pressure balance, toroidal force balance, equilibrium Beta limits, rotational transform, shear, magnetic wall, etc. A wide number of configurations are accurately modeled by the Grad-Shafranov equation. Among them are all types of tokamaks, the spheromak, the reversed field pinch, and toroidal multipoles. An important aspect of the analysis is the use of asymptotic expansions, with an inverse aspect ratio serving as the expansion parameter. In addition, an equation similar to the Grad-Shafranov equation, but for helically symmetric equilibria, is presented. This equation represents the leading-order description low-Beta and high-Beta stellarators, heliacs, and the Elmo bumpy torus. The solutions all correspond to infinitely long straight helices. Bending such a configuration into a torus requires a full three-dimensional calculation and is discussed in Chapter 7
International Nuclear Information System (INIS)
Nimmon, C.C.; McAlister, J.M.; Hickson, B.; Cattell, W.R.
1975-01-01
A comparison of methods for calculating the renal clearance of EDTA from the plasma disappearance curve, after a single injection, has been made. Measurements were made on 38 patients, using external monitoring and venous blood sampling techniques, over a period of 24 h after an injection of 100 μCi of 51 Cr-EDTA. The results indicate that the period 3 - 6 h after injection is suitable for sampling the post-equilibrium part of the plasma disappearance curve for values of the glomerular filtration rate (GFR) in the range 0 - 140 ml/min. It was also found that, to within the individual measurement errors, the values of the clearance calculated by using the post-equilibrium period only (PES clearance) can be considered to show a constant proportionality to the values calculated by using the entire plasma disappearance curve (total clearance). (author)
Digital Repository Service at National Institute of Oceanography (India)
LokaBharathi, P.A.
Microbes, especially bacteria, play an important role in oxidative and reductive cycle of sulfur. The oxidative part of the cycle is mediated by photosynthetic bacteria in the presence of light energy and chemosynthetic forms in the absence of light...
Development and application of Siton, a new fuel cycle simulation code
International Nuclear Information System (INIS)
Brolly, Aron; Szieberth, Mate; Halasz, Mate; Nagy, Lajos; Feher, Sandor
2015-01-01
As the result of the co-operation between the Centre for Energy Research (EK) and the Institute of Nuclear Techniques (NTI) a new fuel cycle simulation code called SITON was developed. Physical model of the code takes into account six facilities of the nuclear fuel cycle namely material stocks, spent fuel interim storages, plants for uranium enrichment, fuel fabrication, spent fuel reprocessing and reactors. Facilities can be linked in a flexible manner and their number is not limited. Lag time of the facilities and cooling time of the spent fuel, which are the two main parameters to introduce lag time into the fuel cycle, are taken into account. Material transfer between the facilities is modelled in a discrete manner tracking 52 nuclides and their short-lived decay daughters. Composition of the discharged fuel is determined by means of burn-up tables except for the 2400 MWth design of gas cooled fast reactor (GFR2400) which has a separate burn-up module developed at the NTI. To demonstrate the capabilities of SITON introduction of a GFR2400 into the Hungarian reactor park using the legacy spent fuel of the four presently operating VVER-440 units was simulated. 2040 was assumed as the commissioning date of the GFR2400 and recycling of its fuel was started as soon as possible. It was found that the plutonium content of the legacy spent fuel is sufficient to the start-up of only one GFR2400. There is an intermediate period between the commissioning of the reactor and the recycling of its first discharged fuel. Plutonium need of this period can be covered by the legacy spent fuel if the cooling time of the spent GFR2400 fuel is 2 years. If the cooling time is 5 years there will be a lack of plutonium in this period. To counterbalance this lack an EPR was started before the GFR2400 and its spent fuel was accumulated and reprocessed. Cooling time of the spent EPR fuel was also varied. Finally, an EPR only scenario is presented using two EPRs as a reference case
International Nuclear Information System (INIS)
Kong Linghua; Wu Junyuan; Gao Bin; Wang Xueqin; Gu Kaikai
2010-01-01
To explore the clinical value between measurement of serum cystatin C (Cys C) and determination of plasma with 99m Tc-DTPA glomerular filtration rate (GFR) clearance for type 2 diabetes (T2DM) in early detection of renal damage, the serum cystatin C levels in 87 patients with type 2 diabetes were determined by immune turbidimetry Cys C. The patients were also carried out dynamic imaging to measure renal GFR. The result showed that the serum levels of Cys C in patients with Type 2 diabetic was 1.68 ± 0.52 mg / L, the normal group was 0.72±0.26 mg/L; The GFR in patients with T2DM was 93.8 ± 30.2 ml/min/1.73m 2 , the control group was 107.48±15.23 ml/min/1.73m 2 , there was significant difference between patients and controls (P 99m Tc-DTPA renal dynamic imaging. The serum Cys C could reflect the damage in early diabetic patients. The method is simple, accurate and easy to spread. The renal dynamic imaging method of GFR determination is slightly complex and requires specialized equipment. It can reflect the sub-renal function. The combined measurement of serum Cys C and GFR are very important in the early detection of type 2 diabetic patients with early renal function. (authors)
Equilibrium calculations and mode analysis
International Nuclear Information System (INIS)
Herrnegger, F.
1987-01-01
The STEP asymptotic stellarator expansion procedure was used to study the MHD equilibrium and stability properties of stellarator configurations without longitudinal net-current, which also apply to advanced stellarators. The effects of toroidal curvature and magnetic well, and the Shafranov shift were investigated. A classification of unstable modes in toroidal stellarators is given. For WVII-A coil-field configurations having a β value of 1% and a parabolic pressure profile, no free-boundary modes are found. This agrees with the experimental fact that unstable behavior of the plasma column is not observed for this parameter range. So a theoretical β-limit for stability against ideal MHD modes can be estimated by mode analysis for the WVII-A device
Stellar Equilibrium in Semiclassical Gravity.
Carballo-Rubio, Raúl
2018-02-09
The phenomenon of quantum vacuum polarization in the presence of a gravitational field is well understood and is expected to have a physical reality, but studies of its backreaction on the dynamics of spacetime are practically nonexistent outside of the specific context of homogeneous cosmologies. Building on previous results of quantum field theory in curved spacetimes, in this Letter we first derive the semiclassical equations of stellar equilibrium in the s-wave Polyakov approximation. It is highlighted that incorporating the polarization of the quantum vacuum leads to a generalization of the classical Tolman-Oppenheimer-Volkoff equation. Despite the complexity of the resulting field equations, it is possible to find exact solutions. Aside from being the first known exact solutions that describe relativistic stars including the nonperturbative backreaction of semiclassical effects, these are identified as a nontrivial combination of the black star and gravastar proposals.
Neoclassical equilibrium in gyrokinetic simulations
International Nuclear Information System (INIS)
Garbet, X.; Dif-Pradalier, G.; Nguyen, C.; Sarazin, Y.; Grandgirard, V.; Ghendrih, Ph.
2009-01-01
This paper presents a set of model collision operators, which reproduce the neoclassical equilibrium and comply with the constraints of a full-f global gyrokinetic code. The assessment of these operators is based on an entropy variational principle, which allows one to perform a fast calculation of the neoclassical diffusivity and poloidal velocity. It is shown that the force balance equation is recovered at lowest order in the expansion parameter, the normalized gyroradius, hence allowing one to calculate correctly the radial electric field. Also, the conventional neoclassical transport and the poloidal velocity are reproduced in the plateau and banana regimes. The advantages and drawbacks of the various model operators are discussed in view of the requirements for neoclassical and turbulent transport.
QUIL: a chemical equilibrium code
International Nuclear Information System (INIS)
Lunsford, J.L.
1977-02-01
A chemical equilibrium code QUIL is described, along with two support codes FENG and SURF. QUIL is designed to allow calculations on a wide range of chemical environments, which may include surface phases. QUIL was written specifically to calculate distributions associated with complex equilibria involving fission products in the primary coolant loop of the high-temperature gas-cooled reactor. QUIL depends upon an energy-data library called ELIB. This library is maintained by FENG and SURF. FENG enters into the library all reactions having standard free energies of reaction that are independent of concentration. SURF enters all surface reactions into ELIB. All three codes are interactive codes written to be used from a remote terminal, with paging control provided. Plotted output is also available
Pre-equilibrium gamma emissions
International Nuclear Information System (INIS)
Ghosh, Sudip
1993-01-01
Together with the direct reaction and the compound nuclear emissions the pre-equilibrium (PEQ) or pre-compound processes give a fairly complete picture of nuclear reactions induced by light ions at energies of some tens of MeV. PEQ particle emissions covering the higher energy continuum spectra have been investigated in detail both experimentally and theoretically. In contrast, very little work has been done on PEQ γ- emissions. The reason is that in spite of extensive work done on PEQ particle emissions, the mechanism is not yet fully understood. Also, the PEQ γ-emission cross-sections (∼ micro barns) are very small compared to the PEQ particle emission cross-sections (∼ milli barns). Yet apart from the academic interest the understanding of PEQ γ-emissions is important for applied fusion research etc. In this paper the PEQ γ-emissions is discussed and the work done in this field is reviewed. (author). 14 refs
Equilibrium Analysis in Cake Cutting
DEFF Research Database (Denmark)
Branzei, Simina; Miltersen, Peter Bro
2013-01-01
Cake cutting is a fundamental model in fair division; it represents the problem of fairly allocating a heterogeneous divisible good among agents with different preferences. The central criteria of fairness are proportionality and envy-freeness, and many of the existing protocols are designed...... to guarantee proportional or envy-free allocations, when the participating agents follow the protocol. However, typically, all agents following the protocol is not guaranteed to result in a Nash equilibrium. In this paper, we initiate the study of equilibria of classical cake cutting protocols. We consider one...... of the simplest and most elegant continuous algorithms -- the Dubins-Spanier procedure, which guarantees a proportional allocation of the cake -- and study its equilibria when the agents use simple threshold strategies. We show that given a cake cutting instance with strictly positive value density functions...
International Nuclear Information System (INIS)
Pigford, T.H.; Ang, K.P.
1975-01-01
The quantities of plutonium and other fuel actinides have been calculated for equilibrium fuel cycles for 1000-MW water reactors fueled with slightly enriched uranium, water reactors fueled with plutonium and natural uranium, fast-breder reactors, gas-cooled reactors fueled with thorium and highly enriched uranium, and gas-cooled reactors fueled with thorium, plutonium and recycled uranium. The radioactivity quantities of plutonium, americium and curium processed yearly in these fuel cycles are greatest for the water reactors fueled with natural uranium and recycled plutonium. The total amount of actinides processed is calculated for the predicted future growth of the U.S. nuclear power industry. For the same total installed nuclear power capacity, the introduction of the plutonium breeder has little effect upon the total amount of plutonium in this century. The estimated amount of plutonium in the low-level process wastes in the plutonium fuel cycles is comparable to the amount of plutonium in the high-level fission product wastes. The amount of plutonium processed in the nuclear fuel cycles can be considerably reduced by using gas-cooled reactors to consume plutonium produced in uranium-fueled water reactors. These, and other reactors dedicated for plutonium utilization, could be co-located with facilities for fuel reprocessing ad fuel fabrication to eliminate the off-site transport of separated plutonium. (author)
Equilibrium Solubility of CO2 in Alkanolamines
DEFF Research Database (Denmark)
Waseem Arshad, Muhammad; Fosbøl, Philip Loldrup; von Solms, Nicolas
2014-01-01
Equilibrium solubility of CO2 were measured in aqueous solutions of Monoethanolamine (MEA) and N,N-diethylethanolamine(DEEA). Equilibrium cells are generally used for these measurements. In this study, the equilibrium data were measured from the calorimetry. For this purpose a reaction calorimeter...... (model CPA 122 from ChemiSens AB, Sweden) was used. The advantage of this method is being the measurement of both heats of absorption and equilibrium solubility data of CO2 at the same time. The measurements were performed for 30 mass % MEA and 5M DEEA solutions as a function of CO2 loading at three...... different temperatures 40, 80 and 120 ºC. The measured 30 mass % MEA and 5M DEEA data were compared with the literature data obtained from different equilibrium cells which validated the use of calorimeters for equilibrium solubility measurements....
Fibroblast Growth Factor-23 and Vitamin D Metabolism in Subjects with eGFR ≥60 ml/min/1.73 m².
Nakatani, Shinya; Nakatani, Ayumi; Tsugawa, Naoko; Yamada, Shinsuke; Mori, Katsuhito; Imanishi, Yasuo; Ishimura, Eiji; Okano, Toshio; Inaba, Masaaki
2015-01-01
Fibroblast growth factor (FGF)-23 and parathyroid hormone (PTH) are both potent phosphaturic hormones. Since they exert opposite effects on vitamin D metabolism, the measurement of 3 vitamin D metabolites; 25-hydroxyvitamin D (25-OH-D), 1,25-dihydroxyvitamin D (1,25(OH)2D), and 24,25-dihydroxyvitamin D (24,25(OH)2D), allows the distinction of the effects of FGF-23 from those of PTH. The aim of this study was to elucidate which factor, FGF-23 or PTH, plays a more important role in the regulation of vitamin D metabolites in subjects with estimated glomerular filtration (eGFR) ≥60 ml/min/1.73 m(2). Subjects with eGFR ≥60 ml/min/1.73 m(2) (n = 20) were enrolled and their serum levels of FGF-23, intact PTH, and vitamin D metabolites were determined. Serum FGF-23 correlated inversely with 1,25(OH)2D (r = -0.717, p = 0.0004) and the 1,25(OH)2D/25-OH-D ratio (r = -0.518, p = 0.019), compared with a significant positive correlation between serum intact PTH and the 1,25(OH)2D/25-OH-D ratio (r = 0.562, p = 0.010). Multiple regression analyses revealed serum FGF-23 as a significant factor that was associated with serum 1,25(OH)2D (β = -0.593, p = 0.018), 1,25(OH)2D/25-OH-D ratio (β = -0.521, p = 0.025), and the 24,25(OH)2D/1,25(OH)2D ratio (β = 0.632, p = 0.008), and intact PTH as a significant factor associated with the 1,25(OH)2D/25-OH-D ratio (β = 0.445, p = 0.028). This study demonstrated that, even in subjects with eGFR ≥60 ml/min/1.73 m(2), FGF-23 might play an important role in the regulation of vitamin D metabolism. In addition to the established role of PTH, the association between FGF-23 and indices of vitamin D metabolism suggested the potential role of FGF-23 on phosphate metabolism in such patients. © 2015 S. Karger AG, Basel.
Mathematical models and equilibrium in irreversible microeconomics
Directory of Open Access Journals (Sweden)
Anatoly M. Tsirlin
2010-07-01
Full Text Available A set of equilibrium states in a system consisting of economic agents, economic reservoirs, and firms is considered. Methods of irreversible microeconomics are used. We show that direct sale/purchase leads to an equilibrium state which depends upon the coefficients of supply/demand functions. To reach the unique equilibrium state it is necessary to add either monetary exchange or an intermediate firm.
Collapse and equilibrium of rotating, adiabatic clouds
International Nuclear Information System (INIS)
Boss, A.P.
1980-01-01
A numerical hydrodynamics computer code has been used to follow the collapse and establishment of equilibrium of adiabatic gas clouds restricted to axial symmetry. The clouds are initially uniform in density and rotation, with adiabatic exponents γ=5/3 and 7/5. The numerical technique allows, for the first time, a direct comparison to be made between the dynamic collapse and approach to equilibrium of unconstrained clouds on the one hand, and the results for incompressible, uniformly rotating equilibrium clouds, and the equilibrium structures of differentially rotating polytropes, on the other hand
Equilibrium sampling by reweighting nonequilibrium simulation trajectories.
Yang, Cheng; Wan, Biao; Xu, Shun; Wang, Yanting; Zhou, Xin
2016-03-01
Based on equilibrium molecular simulations, it is usually difficult to efficiently visit the whole conformational space of complex systems, which are separated into some metastable regions by high free energy barriers. Nonequilibrium simulations could enhance transitions among these metastable regions and then be applied to sample equilibrium distributions in complex systems, since the associated nonequilibrium effects can be removed by employing the Jarzynski equality (JE). Here we present such a systematical method, named reweighted nonequilibrium ensemble dynamics (RNED), to efficiently sample equilibrium conformations. The RNED is a combination of the JE and our previous reweighted ensemble dynamics (RED) method. The original JE reproduces equilibrium from lots of nonequilibrium trajectories but requires that the initial distribution of these trajectories is equilibrium. The RED reweights many equilibrium trajectories from an arbitrary initial distribution to get the equilibrium distribution, whereas the RNED has both advantages of the two methods, reproducing equilibrium from lots of nonequilibrium simulation trajectories with an arbitrary initial conformational distribution. We illustrated the application of the RNED in a toy model and in a Lennard-Jones fluid to detect its liquid-solid phase coexistence. The results indicate that the RNED sufficiently extends the application of both the original JE and the RED in equilibrium sampling of complex systems.
Static Equilibrium Configurations of Charged Metallic Bodies
African Journals Online (AJOL)
Key words: Static equilibrium, charged metallic body, potential energy, projected gradient method. ... television, radio, internet, microwave ovens, mobile telephones, satellite communication systems, radar systems, electrical motors, electrical.
Digital calculations of engine cycles
Starkman, E S; Taylor, C Fayette
1964-01-01
Digital Calculations of Engine Cycles is a collection of seven papers which were presented before technical meetings of the Society of Automotive Engineers during 1962 and 1963. The papers cover the spectrum of the subject of engine cycle events, ranging from an examination of composition and properties of the working fluid to simulation of the pressure-time events in the combustion chamber. The volume has been organized to present the material in a logical sequence. The first two chapters are concerned with the equilibrium states of the working fluid. These include the concentrations of var
Equilibrium Temperature Profiles within Fission Product Waste Forms
Energy Technology Data Exchange (ETDEWEB)
Kaminski, Michael D. [Argonne National Lab. (ANL), Argonne, IL (United States)
2016-10-01
We studied waste form strategies for advanced fuel cycle schemes. Several options were considered for three waste streams with the following fission products: cesium and strontium, transition metals, and lanthanides. These three waste streams may be combined or disposed separately. The decay of several isotopes will generate heat that must be accommodated by the waste form, and this heat will affect the waste loadings. To help make an informed decision on the best option, we present computational data on the equilibrium temperature of glass waste forms containing a combination of these three streams.
Energy Technology Data Exchange (ETDEWEB)
Perusquia, R.; Ortiz, J.J.; Montes, J.L. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: rpc@nuclear.inin.mx
2003-07-01
Nowadays in the National Institute of Nuclear Research are carried out studies with some bio-inspired optimization techniques to improve the performance of the fuel cycles of the boiling water reactors of the Laguna Verde power plant (CLV). In the present work two bio-inspired techniques were applied with the purpose of improving the performance of a balance cycle of 18 months developed for the CLV: genetic algorithms (AG) and systems based on ants colonies (SCH). The design of the reference cycle it represents in several aspects an optimal cycle proposed starting from the experience of several operation decades with the boiling water reactors (BWR initials for Boiling Water Reactor) in the world. To try to improve their performance is beforehand a difficult challenge and it puts on test the feasibility of the optimization methods in the reloads design. The study of the bio-inspired techniques was centered exclusively on the obtaining of the control rod patterns (PBC) trying to overcome the capacity factor reached in the design of the reference cycle. It was fixed the cycle length such that the decrease of the coast down period would represent an increase of the capacity factor of the cycle; so that, it diminishes the annual cost associated with the capital cost of the plant. As consequence of the study, was found that the algorithm based on the ants colonies reaches to diminish the coast down period in five and half days respect to the original balance cycle, what represents an annual saving of $US 74,000. Since the original cycle was optimized, the above-mentioned, shows the ability of the SCH for the optimization of the cycle design. With the AG it was reach to approach to the original balance cycle with a coast down period greater in seven days estimating an annual penalization of $US 130,000. (Author)
International Nuclear Information System (INIS)
Camargo, E.E.; Rockmann, R.L.; Barreto, T.M.; Eston, T.E.; Papaleo Netto, M.; Carvalho, N.
1974-01-01
Through a logarithmic regression performed with the contings of 4 plasma samples withdrawn at 20,40,60 and 80 minutes after a venous injection of vitamin B 12 - 57 Co, the glomerular filtration-rate(GFR) in 11 patients, performing simultaneously the same study with EDTA- 51 Cr in 3 of them, is evaluated. The values obtained through the regression straight line are compared with those given by only 2 points, in the 6 possible combinations: 20 and 40 minutes, 20 and 60 minutes, 20 and 80 minutes, 40 and 60 minutes, 40 and 80 minutes, 60 and 80 minutes. The pair of points obtained at 20 and 80 minutes determined the straight line most similar to the logarithmic regression and as a simplification of the method, the withdraw of only 2 plasma samples, at and 80 minutes after a single injection of vitamin B 12 -57 Co is proposed [pt
RINGED ACCRETION DISKS: EQUILIBRIUM CONFIGURATIONS
Energy Technology Data Exchange (ETDEWEB)
Pugliese, D.; Stuchlík, Z., E-mail: d.pugliese.physics@gmail.com, E-mail: zdenek.stuchlik@physics.cz [Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Silesian University in Opava, Bezručovo náměstí 13, CZ-74601 Opava (Czech Republic)
2015-12-15
We investigate a model of a ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the general relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can then be determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We present also a perturbation analysis based on evolution of the oscillating components of the ringed disk. The dynamics of the unstable phases of the ringed disk evolution seems to be promising in relation to high-energy phenomena demonstrated in active galactic nuclei.
Equilibrium figures in geodesy and geophysics.
Moritz, H.
There is an enormous literature on geodetic equilibrium figures, but the various works have not always been interrelated, also for linguistic reasons (English, French, German, Italian, Russian). The author attempts to systematize the various approaches and to use the standard second-order theory for a study of the deviation of the actual earth and of the equipotential reference ellipsoid from an equilibrium figure.
Equilibrium theory of island biogeography: A review
Angela D. Yu; Simon A. Lei
2001-01-01
The topography, climatic pattern, location, and origin of islands generate unique patterns of species distribution. The equilibrium theory of island biogeography creates a general framework in which the study of taxon distribution and broad island trends may be conducted. Critical components of the equilibrium theory include the species-area relationship, island-...
Gibbs equilibrium averages and Bogolyubov measure
International Nuclear Information System (INIS)
Sankovich, D.P.
2011-01-01
Application of the functional integration methods in equilibrium statistical mechanics of quantum Bose-systems is considered. We show that Gibbs equilibrium averages of Bose-operators can be represented as path integrals over a special Gauss measure defined in the corresponding space of continuous functions. We consider some problems related to integration with respect to this measure
Do intertidal flats ever reach equilibrium?
Maan, D.C.; van Prooijen, B.C.; Wang, Z.B.; de Vriend, H.J.
2015-01-01
Various studies have identified a strong relation between the hydrodynamic forces and the equilibrium profile for intertidal flats. A thorough understanding of the interplay between the hydrodynamic forces and the morphology, however, concerns more than the equilibrium state alone. We study the
Vertical field and equilibrium calculation in ETE
International Nuclear Information System (INIS)
Montes, Antonio; Shibata, Carlos Shinya.
1996-01-01
The free-boundary MHD equilibrium code HEQ is used to study the plasma behaviour in the tokamak ETE, with optimized compensations coils and vertical field coils. The changes on the equilibrium parameters for different plasma current values are also investigated. (author). 5 refs., 4 figs., 2 tabs
Statistical thermodynamics of equilibrium polymers at interfaces
Gucht, van der J.; Besseling, N.A.M.
2002-01-01
The behavior of a solution of equilibrium polymers (or living polymers) at an interface is studied, using a Bethe-Guggenheim lattice model for molecules with orientation dependent interactions. The density profile of polymers and the chain length distribution are calculated. For equilibrium polymers
Non-equilibrium modelling of distillation
Wesselingh, JA; Darton, R
1997-01-01
There are nasty conceptual problems in the classical way of describing distillation columns via equilibrium stages, and efficiencies or HETP's. We can nowadays avoid these problems by simulating the behaviour of a complete column in one go using a non-equilibrium model. Such a model has phase
Thermodynamics of open, nonisothermal chemical systems far from equilibrium
International Nuclear Information System (INIS)
Yoshida, Nobuo
1992-01-01
The thermodynamic behavior of kinetic models based on a continuously stirred tank reactor (CSTR) is studied in an attempt to seek general trends in the thermodynamic properties of open nonlinear systems. The models consist of two reversible reactions, A + nB rightleftharpoons (n + 1) B (n = 0,1,or 2) and B rightleftharpoons C, taking place in an adiabatic CSTR. The heat of reaction is incorporated, and the rate constants are assumed to follow an Arrhenius temperature dependence. The models give rise to multiple stationary states and sustained oscillations (limit cycles). The entropy difference between stationary or oscillatory states and equilibrium and the rate of entropy production in the these states are calculated as a function of the residence time in the reactor. The entropy difference and entropy production may be taken, to some extent, as indicative of the influence of irreversible processes, which disappears at equilibrium. The results of the calculations reveal the following systematic trends: (I) The entropy difference or entropy production for stable states or both always increase as the residence time is shortened, namely, as the system is displaced further from equilibrium. (II) If stable and unstable states (stationary or oscillatory) coexist under identical conditions, then the stable state invariably has a smaller value of the entropy difference or entropy production or both than the corresponding unstable state. 26 refs., 3 figs
Ghirardi, Marco; Marchetti, Fabio; Pettinari, Claudio; Regis, Alberto; Roletto, Ezio
2015-01-01
A didactic sequence is proposed for the teaching of chemical equilibrium law. In this approach, we have avoided the kinetic derivation and the thermodynamic justification of the equilibrium constant. The equilibrium constant expression is established empirically by a trial-and-error approach. Additionally, students learn to use the criterion of…
On the definition of equilibrium and non-equilibrium states in dynamical systems
Akimoto, Takuma
2008-01-01
We propose a definition of equilibrium and non-equilibrium states in dynamical systems on the basis of the time average. We show numerically that there exists a non-equilibrium non-stationary state in the coupled modified Bernoulli map lattice.
The continuous fuel cycle model and the gas cooled fast reactor
International Nuclear Information System (INIS)
Christie, Stuart; Lathouwers, Danny; Kloosterman, Jan Leen; Hagen, Tim van der
2011-01-01
The gas cooled fast reactor (GFR) is one of the generation IV designs currently being evaluated for future use. It is intended to behave as an isobreeder, producing the same amount of fuel as it consumes during operation. The actinides in the fuel will be recycled repeatedly in order to minimise the waste output to fission products only. Striking the balance of the fissioning of various actinides against transmutation and decay to achieve these goals is a complex problem. This is compounded by the time required for burn-up modelling, which can be considerable for a single cycle, and even longer for studies of fuel evolution over many cycles. The continuous fuel cycle model approximates the discrete steps of loading, operating and unloading a reactor as continuous processes. This simplifies the calculations involved in simulating the behaviour of the fuel, reducing the time needed to model the changes to the fuel composition over many cycles. This method is used to study the behaviour of GFR fuel over many cycles and compared to results obtained from direct calculations. The effects of varying fuel cycle properties such as feed material, recycling of additional actinides and reprocessing losses are also investigated. (author)
Information-theoretic equilibrium and observable thermalization
Anzà, F.; Vedral, V.
2017-03-01
A crucial point in statistical mechanics is the definition of the notion of thermal equilibrium, which can be given as the state that maximises the von Neumann entropy, under the validity of some constraints. Arguing that such a notion can never be experimentally probed, in this paper we propose a new notion of thermal equilibrium, focused on observables rather than on the full state of the quantum system. We characterise such notion of thermal equilibrium for an arbitrary observable via the maximisation of its Shannon entropy and we bring to light the thermal properties that it heralds. The relation with Gibbs ensembles is studied and understood. We apply such a notion of equilibrium to a closed quantum system and show that there is always a class of observables which exhibits thermal equilibrium properties and we give a recipe to explicitly construct them. Eventually, an intimate connection with the Eigenstate Thermalisation Hypothesis is brought to light.
Disturbances in equilibrium function after major earthquake.
Honma, Motoyasu; Endo, Nobutaka; Osada, Yoshihisa; Kim, Yoshiharu; Kuriyama, Kenichi
2012-01-01
Major earthquakes were followed by a large number of aftershocks and significant outbreaks of dizziness occurred over a large area. However it is unclear why major earthquake causes dizziness. We conducted an intergroup trial on equilibrium dysfunction and psychological states associated with equilibrium dysfunction in individuals exposed to repetitive aftershocks versus those who were rarely exposed. Greater equilibrium dysfunction was observed in the aftershock-exposed group under conditions without visual compensation. Equilibrium dysfunction in the aftershock-exposed group appears to have arisen from disturbance of the inner ear, as well as individual vulnerability to state anxiety enhanced by repetitive exposure to aftershocks. We indicate potential effects of autonomic stress on equilibrium function after major earthquake. Our findings may contribute to risk management of psychological and physical health after major earthquakes with aftershocks, and allow development of a new empirical approach to disaster care after such events.
Equilibrium mercury isotope fractionation between dissolved Hg(II) species and thiol-bound Hg
Wiederhold, Jan G.; Cramer, Christopher J.; Daniel, Kelly; Infante, Ivan; Bourdon, Bernard; Kretzschmar, Ruben
2010-01-01
Stable Hg isotope ratios provide a new tool to trace environmental Hg cycling. Thiols (-SH) are the dominant Hg-binding groups in natural organic matter. Here, we report experimental and computational results on equilibrium Hg isotope fractionation between dissolved Hg(II) species and thiol-bound
Pension Fund Restoration Policy in General Equilibrium : Tinbergen Institute MPhil Thesis
Kastelein, P.
2016-01-01
This paper quantifies the business cycle effects and distributional implications of pension fund restoration policy after the economy has been hit by a financial shock. We extend a canonical New-Keynesian dynamic general equilibrium model with a tractable demographic structure and a pension fund.
Isospin equilibrium and non-equilibrium in heavy-ion collisions at intermediate energies
International Nuclear Information System (INIS)
Chen Liewen; Ge Lingxiao; Zhang Xiaodong; Zhang Fengshou
1997-01-01
The equilibrium and non-equilibrium of the isospin degree of freedom are studied in terms of an isospin-dependent QMD model, which includes isospin-dependent symmetry energy, Coulomb energy, N-N cross sections and Pauli blocking. It is shown that there exists a transition from the isospin equilibrium to non-equilibrium as the incident energy from below to above a threshold energy in central, asymmetric heavy-ion collisions. Meanwhile, it is found that the phenomenon results from the co-existence and competition of different reaction mechanisms, namely, the isospin degree of freedom reaches an equilibrium if the incomplete fusion (ICF) component is dominant and does not reach equilibrium if the fragmentation component is dominant. Moreover, it is also found that the isospin-dependent N-N cross sections and symmetry energy are crucial for the equilibrium of the isospin degree of freedom in heavy-ion collisions around the Fermi energy. (author)
Local Nash equilibrium in social networks.
Zhang, Yichao; Aziz-Alaoui, M A; Bertelle, Cyrille; Guan, Jihong
2014-08-29
Nash equilibrium is widely present in various social disputes. As of now, in structured static populations, such as social networks, regular, and random graphs, the discussions on Nash equilibrium are quite limited. In a relatively stable static gaming network, a rational individual has to comprehensively consider all his/her opponents' strategies before they adopt a unified strategy. In this scenario, a new strategy equilibrium emerges in the system. We define this equilibrium as a local Nash equilibrium. In this paper, we present an explicit definition of the local Nash equilibrium for the two-strategy games in structured populations. Based on the definition, we investigate the condition that a system reaches the evolutionary stable state when the individuals play the Prisoner's dilemma and snow-drift game. The local Nash equilibrium provides a way to judge whether a gaming structured population reaches the evolutionary stable state on one hand. On the other hand, it can be used to predict whether cooperators can survive in a system long before the system reaches its evolutionary stable state for the Prisoner's dilemma game. Our work therefore provides a theoretical framework for understanding the evolutionary stable state in the gaming populations with static structures.
Energy Technology Data Exchange (ETDEWEB)
Talakic, Emina; Steiner, Jürgen; Kalmar, Peter; Lutfi, Andre [Division of General Radiology, Department of Radiology, Medical University of Graz, Auenbruggerplatz 9, 8036 Graz (Austria); Quehenberger, Franz [Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, Auenbruggerplatz 2, 8036 Graz (Austria); Reiter, Ursula; Fuchsjäger, Michael [Division of General Radiology, Department of Radiology, Medical University of Graz, Auenbruggerplatz 9, 8036 Graz (Austria); Schöllnast, Helmut, E-mail: helmut.schoellnast@medunigraz.at [Division of General Radiology, Department of Radiology, Medical University of Graz, Auenbruggerplatz 9, 8036 Graz (Austria)
2014-04-15
Objectives: To assess the correlation of relative hepatic enhancement (RHE), relative renal enhancement (RRE) and liver to kidneys enhancement ratio (LKR) with serum hepatic enzyme levels and eGFR in Gd-EOB-DTPA enhanced MRI of the liver and to assess threshold levels for predicting enhancement of the liver parenchyma. Methods: Data of 75 patients who underwent Gd-EOB-DTPA enhanced MRI of the liver were collected. Images were obtained before contrast injection, during the early arterial phase, late arterial phase, venous phase, delayed phase, and hepatobiliary phase which was 20 min after Gd-EOB-DTPA administration. Signal intensity of the liver and the kidneys in all phases was defined using region-of-interest measurements for relative enhancement calculation. Serum hepatic enzyme levels and eGFR were available in all patients. Spearman correlation test was used to test the correlation of RHE, RRE and LKR with serum hepatic enzyme levels and eGFR. Results: In the hepatobiliary phase all serum hepatic enzymes were significantly correlated with RHE; total bilirubin (TBIL) and cholin esterase (CHE) showed strongest correlations. TBIL and CHE were significantly correlated with RRE in the arterial phases. TBIL and CHE were significantly correlated with LKR in the arterial phase and hepatobiliary phase. eGFR showed no correlation. Conclusions: In Gd-EOB-DTPA enhanced MRI, TBIL and CHE levels may predict RHE, RRE and LKR.
Teaching Chemical Equilibrium with the Jigsaw Technique
Doymus, Kemal
2008-03-01
This study investigates the effect of cooperative learning (jigsaw) versus individual learning methods on students’ understanding of chemical equilibrium in a first-year general chemistry course. This study was carried out in two different classes in the department of primary science education during the 2005-2006 academic year. One of the classes was randomly assigned as the non-jigsaw group (control) and other as the jigsaw group (cooperative). Students participating in the jigsaw group were divided into four “home groups” since the topic chemical equilibrium is divided into four subtopics (Modules A, B, C and D). Each of these home groups contained four students. The groups were as follows: (1) Home Group A (HGA), representin g the equilibrium state and quantitative aspects of equilibrium (Module A), (2) Home Group B (HGB), representing the equilibrium constant and relationships involving equilibrium constants (Module B), (3) Home Group C (HGC), representing Altering Equilibrium Conditions: Le Chatelier’s principle (Module C), and (4) Home Group D (HGD), representing calculations with equilibrium constants (Module D). The home groups then broke apart, like pieces of a jigsaw puzzle, and the students moved into jigsaw groups consisting of members from the other home groups who were assigned the same portion of the material. The jigsaw groups were then in charge of teaching their specific subtopic to the rest of the students in their learning group. The main data collection tool was a Chemical Equilibrium Achievement Test (CEAT), which was applied to both the jigsaw and non-jigsaw groups The results indicated that the jigsaw group was more successful than the non-jigsaw group (individual learning method).
DEFF Research Database (Denmark)
Kaufmann, R. K.; Juselius, Katarina
We use a statistical model, the cointegrated vector autoregressive model, to assess the degree to which variations in Earth's orbit and endogenous climate dynamics can be used to simulate glacial cycles during the late Quaternary (390 kyr-present). To do so, we estimate models of varying complexity...... and compare the accuracy of their in-sample simulations. Results indicate that strong statistical associations between endogenous climate variables are not enough for statistical models to reproduce glacial cycles. Rather, changes in solar insolation associated with changes in Earth's orbit are needed...... to simulate glacial cycles accurately. Also, results suggest that non-linear 10 dynamics, threshold effects, and/or free oscillations may not play an overriding role in glacial cycles....
International Nuclear Information System (INIS)
Hawley, N.J.
1983-05-01
AECL publications, from the open literature, on fuels and fuel cycles used in CANDU reactors are listed in this bibliography. The accompanying index is by subject. The bibliography will be brought up to date periodically
Changing Credit Limits, Changing Business Cycles
DEFF Research Database (Denmark)
Jensen, Henrik; Ravn, Søren Hove; Santoro, Emiliano
In the last decades, capital markets across the industrialized world have undergone massive deregulation, involving increases in the loan-to-value (LTV) ratios of households and firms. We study the business-cycle implications of this phenomenon in a dynamic general equilibrium model with multiple...
Nonideal plasmas as non-equilibrium media
International Nuclear Information System (INIS)
Morozov, I V; Norman, G E; Valuev, A A; Valuev, I A
2003-01-01
Various aspects of the collective behaviour of non-equilibrium nonideal plasmas are studied. The relaxation of kinetic energy to the equilibrium state is simulated by the molecular dynamics (MD) method for two-component non-degenerate strongly non-equilibrium plasmas. The initial non-exponential stage, its duration and the subsequent exponential stage of the relaxation process are studied for a wide range of ion charge, nonideality parameter and ion mass. A simulation model of the nonideal plasma excited by an electron beam is proposed. An approach is developed to calculate the dynamic structure factor in non-stationary conditions. Instability increment is obtained from MD simulations
MHD equilibrium identification on ASDEX-Upgrade
International Nuclear Information System (INIS)
McCarthy, P.J.; Schneider, W.; Lakner, K.; Zehrfeld, H.P.; Buechl, K.; Gernhardt, J.; Gruber, O.; Kallenbach, A.; Lieder, G.; Wunderlich, R.
1992-01-01
A central activity accompanying the ASDEX-Upgrade experiment is the analysis of MHD equilibria. There are two different numerical methods available, both using magnetic measurements which reflect equilibrium states of the plasma. The first method proceeds via a function parameterization (FP) technique, which uses in-vessel magnetic measurements to calculate up to 66 equilibrium parameters. The second method applies an interpretative equilibrium code (DIVA) for a best fit to a different set of magnetic measurements. Cross-checks with the measured particle influxes from the inner heat shield and the divertor region and with visible camera images of the scrape-off layer are made. (author) 3 refs., 3 figs
Numerical method for partial equilibrium flow
International Nuclear Information System (INIS)
Ramshaw, J.D.; Cloutman, L.D.; Los Alamos, New Mexico 87545)
1981-01-01
A numerical method is presented for chemically reactive fluid flow in which equilibrium and nonequilibrium reactions occur simultaneously. The equilibrium constraints on the species concentrations are established by a quadratic iterative procedure. If the equilibrium reactions are uncoupled and of second or lower order, the procedure converges in a single step. In general, convergence is most rapid when the reactions are weakly coupled. This can frequently be achieved by a judicious choice of the independent reactions. In typical transient calculations, satisfactory accuracy has been achieved with about five iterations per time step
The Conceptual Change Approach to Teaching Chemical Equilibrium
Canpolat, Nurtac; Pinarbasi, Tacettin; Bayrakceken, Samih; Geban, Omer
2006-01-01
This study investigates the effect of a conceptual change approach over traditional instruction on students' understanding of chemical equilibrium concepts (e.g. dynamic nature of equilibrium, definition of equilibrium constant, heterogeneous equilibrium, qualitative interpreting of equilibrium constant, changing the reaction conditions). This…
Dissipation and the relaxation to equilibrium
International Nuclear Information System (INIS)
Evans, Denis J; Williams, Stephen R; Searles, Debra J
2009-01-01
Using the recently derived dissipation theorem and a corollary of the transient fluctuation theorem (TFT), namely the second-law inequality, we derive the unique time independent, equilibrium phase space distribution function for an ergodic Hamiltonian system in contact with a remote heat bath. We prove under very general conditions that any deviation from this equilibrium distribution breaks the time independence of the distribution. Provided temporal correlations decay, we show that any nonequilibrium distribution that is an even function of the momenta eventually relaxes (not necessarily monotonically) to the equilibrium distribution. Finally we prove that the negative logarithm of the microscopic partition function is equal to the thermodynamic Helmholtz free energy divided by the thermodynamic temperature and Boltzmann's constant. Our results complement and extend the findings of modern ergodic theory and show the importance of dissipation in the process of relaxation towards equilibrium
Computation of Phase Equilibrium and Phase Envelopes
DEFF Research Database (Denmark)
Ritschel, Tobias Kasper Skovborg; Jørgensen, John Bagterp
formulate the involved equations in terms of the fugacity coefficients. We present expressions for the first-order derivatives. Such derivatives are necessary in computationally efficient gradient-based methods for solving the vapor-liquid equilibrium equations and for computing phase envelopes. Finally, we......In this technical report, we describe the computation of phase equilibrium and phase envelopes based on expressions for the fugacity coefficients. We derive those expressions from the residual Gibbs energy. We consider 1) ideal gases and liquids modeled with correlations from the DIPPR database...... and 2) nonideal gases and liquids modeled with cubic equations of state. Next, we derive the equilibrium conditions for an isothermal-isobaric (constant temperature, constant pressure) vapor-liquid equilibrium process (PT flash), and we present a method for the computation of phase envelopes. We...
Intermittent many-body dynamics at equilibrium
Danieli, C.; Campbell, D. K.; Flach, S.
2017-06-01
The equilibrium value of an observable defines a manifold in the phase space of an ergodic and equipartitioned many-body system. A typical trajectory pierces that manifold infinitely often as time goes to infinity. We use these piercings to measure both the relaxation time of the lowest frequency eigenmode of the Fermi-Pasta-Ulam chain, as well as the fluctuations of the subsequent dynamics in equilibrium. The dynamics in equilibrium is characterized by a power-law distribution of excursion times far off equilibrium, with diverging variance. Long excursions arise from sticky dynamics close to q -breathers localized in normal mode space. Measuring the exponent allows one to predict the transition into nonergodic dynamics. We generalize our method to Klein-Gordon lattices where the sticky dynamics is due to discrete breathers localized in real space.
Moisture transport and equilibrium in organic coatings
Wel, van der G.K.; Adan, O.C.G.
2000-01-01
Improving coating performance in regard of protection of substrates and structures against moisturerelated degradation requires detailed knowledge of underlying transport mechanisms. In this paper a review is given on transport and equilibrium sorption of moisture in polymer films and organic
Non-equilibrium entropy in excited nuclei
International Nuclear Information System (INIS)
Betak, E.
1991-06-01
The time-dependent behaviour of entropy in excited nuclei is investigated. In distinction to recent claims, it is shown that no self-organization is involved in pre-equilibrium nuclear reactions. (author). 9 refs.; 4 figs
Plasma equilibrium and instabilities in tokamaks
International Nuclear Information System (INIS)
Caldas, I.L.; Vannucci, A.
1985-01-01
A phenomenological introduction of some of the main theoretical and experimental features on equilibrium and instabilities in tokamaks is presented. In general only macroscopic effects are considered, being the plasma described as a fluid. (L.C.) [pt
"Secrets" of High Pressure Phase Equilibrium Experiment.
Czech Academy of Sciences Publication Activity Database
Wichterle, Ivan
2005-01-01
Roč. 54, č. 11 (2005), s. 477-479 ISSN 0022-9830 Institutional research plan: CEZ:AV0Z40720504 Keywords : vapour-liquid equilibrium * experimental work Subject RIV: CF - Physical ; Theoretical Chemistry
Averaged description of 3D MHD equilibrium
International Nuclear Information System (INIS)
Medvedev, S.Yu.; Drozdov, V.V.; Ivanov, A.A.; Martynov, A.A.; Pashekhonov, Yu.Yu.; Mikhailov, M.I.
2001-01-01
A general approach by S.A.Galkin et al. in 1991 to 2D description of MHD equilibrium and stability in 3D systems was proposed. The method requires a background 3D equilibrium with nested flux surfaces to generate the metric of a Riemannian space in which the background equilibrium is described by the 2D equation of Grad-Shafranov type. The equation can be solved then varying plasma profiles and shape to get approximate 3D equilibria. In the framework of the method both planar axis conventional stellarators and configurations with spatial magnetic axis can be studied. In the present report the formulation and numerical realization of the equilibrium problem for stellarators with planar axis is reviewed. The input background equilibria with nested flux surfaces are taken from vacuum magnetic field approximately described by analytic scalar potential
Equilibrium-torus bifurcation in nonsmooth systems
DEFF Research Database (Denmark)
Zhusubahyev, Z.T.; Mosekilde, Erik
2008-01-01
Considering a set of two coupled nonautonomous differential equations with discontinuous right-hand sides describing the behavior of a DC/DC power converter, we discuss a border-collision bifurcation that can lead to the birth of a two-dimensional invariant torus from a stable node equilibrium...... point. We obtain the chart of dynamic modes and show that there is a region of parameter space in which the system has a single stable node equilibrium point. Under variation of the parameters, this equilibrium may disappear as it collides with a discontinuity boundary between two smooth regions...... in the phase space. The disappearance of the equilibrium point is accompanied by the soft appearance of an unstable focus period-1 orbit surrounded by a resonant or ergodic torus. Detailed numerical calculations are supported by a theoretical investigation of the normal form map that represents the piecewise...
Stochastic approach to equilibrium and nonequilibrium thermodynamics.
Tomé, Tânia; de Oliveira, Mário J
2015-04-01
We develop the stochastic approach to thermodynamics based on stochastic dynamics, which can be discrete (master equation) and continuous (Fokker-Planck equation), and on two assumptions concerning entropy. The first is the definition of entropy itself and the second the definition of entropy production rate, which is non-negative and vanishes in thermodynamic equilibrium. Based on these assumptions, we study interacting systems with many degrees of freedom in equilibrium or out of thermodynamic equilibrium and how the macroscopic laws are derived from the stochastic dynamics. These studies include the quasiequilibrium processes; the convexity of the equilibrium surface; the monotonic time behavior of thermodynamic potentials, including entropy; the bilinear form of the entropy production rate; the Onsager coefficients and reciprocal relations; and the nonequilibrium steady states of chemical reactions.
The Theory of Variances in Equilibrium Reconstruction
International Nuclear Information System (INIS)
Zakharov, Leonid E.; Lewandowski, Jerome; Foley, Elizabeth L.; Levinton, Fred M.; Yuh, Howard Y.; Drozdov, Vladimir; McDonald, Darren
2008-01-01
The theory of variances of equilibrium reconstruction is presented. It complements existing practices with information regarding what kind of plasma profiles can be reconstructed, how accurately, and what remains beyond the abilities of diagnostic systems. The σ-curves, introduced by the present theory, give a quantitative assessment of quality of effectiveness of diagnostic systems in constraining equilibrium reconstructions. The theory also suggests a method for aligning the accuracy of measurements of different physical nature
Quasi-equilibrium interpretation of aging dynamics
International Nuclear Information System (INIS)
Franz, S.; Virasoro, M.A.
2000-04-01
We develop an interpretation of the off-equilibrium dynamical solution of mean-field glassy models in terms of quasi-equilibrium concepts. We show that the relaxation of the 'thermoremanent magnetization' follows a generalized version of the Onsager regression postulate of induced fluctuations. We then find the rationale for the equality between the fluctuation-dissipation ratio and the rate of growth of the configurational entropy close to the asymptotic state, found empirically in mean-field solutions. (author)
Equivalence of Equilibrium Propagation and Recurrent Backpropagation
Scellier, Benjamin; Bengio, Yoshua
2017-01-01
Recurrent Backpropagation and Equilibrium Propagation are algorithms for fixed point recurrent neural networks which differ in their second phase. In the first phase, both algorithms converge to a fixed point which corresponds to the configuration where the prediction is made. In the second phase, Recurrent Backpropagation computes error derivatives whereas Equilibrium Propagation relaxes to another nearby fixed point. In this work we establish a close connection between these two algorithms....
Non-equilibrium dog-flea model
Ackerson, Bruce J.
2017-11-01
We develop the open dog-flea model to serve as a check of proposed non-equilibrium theories of statistical mechanics. The model is developed in detail. Then it is applied to four recent models for non-equilibrium statistical mechanics. Comparison of the dog-flea solution with these different models allows checking claims and giving a concrete example of the theoretical models.
Internal equilibrium layer growth over forest
DEFF Research Database (Denmark)
Dellwik, E.; Jensen, N.O.
2000-01-01
the magnitude of the scatter. Different theoretical friction velocity profiles for the Internal Boundary Layer (IBL) are tested against the forest data. The results yield information on the Internal Equilibrium Layer (IEL) growth and an equation for the IEL height fur neutral conditions is derived. For stable...... conditions the results indicate that very long fetches are required in order to measure parameters in equilibrium with the actual surface....
Equilibrium fluctuation energy of gyrokinetic plasma
International Nuclear Information System (INIS)
Krommes, J.A.; Lee, W.W.; Oberman, C.
1985-11-01
The thermal equilibrium electric field fluctuation energy of the gyrokinetic model of magnetized plasma is computed, and found to be smaller than the well-known result (k)/8π = 1/2T/[1 + (klambda/sub D/) 2 ] valid for arbitrarily magnetized plasmas. It is shown that, in a certain sense, the equilibrium electric field energy is minimum in the gyrokinetic regime. 13 refs., 2 figs
Support of the extremal measure in a vector equilibrium problem
International Nuclear Information System (INIS)
Lapik, M A
2006-01-01
A generalization of the Mhaskar-Saff functional is obtained for a vector equilibrium problem with an external field. As an application, the supports of the equilibrium measures are found in a special vector equilibrium problem with Nikishin matrix.
International Nuclear Information System (INIS)
Seino, Takeshi; Sekimoto, Hiroshi
1997-01-01
There have been some difficulties in carrying out an extensive evaluation of the equilibrium state of Light Water Reactor (LWR) recycling operations keeping their fixed criticality condition using conventional design codes, because of the complexity of their calculational model for practical fuel and core design and because of a large amount of calculation time. This study presents an efficient approach to secure the criticality in an equilibrium cycle by adjusting a supplied fuel composition. The criticality search is performed by the use of fuel importance obtained from the equilibrium adjoint to a continuously fuel supplied core burnup equation. Using this method, some numerical analyses were carried out in order to evaluate the mixed oxide (MOX) fuel composition of equilibrium Boiling Water Reactor (BWR) cores satisfying the criticality requirement. The results showed the comprehensive and quantitative characteristics on the equilibrium cores confining transuranium for different MOX fuel loading fractions and irradiating conditions. (author)
Khanh, Phan Quoc; Plubtieng, Somyot; Sombut, Kamonrat
2014-01-01
The purpose of this paper is introduce several types of Levitin-Polyak well-posedness for bilevel vector equilibrium and optimization problems with equilibrium constraints. Base on criterion and characterizations for these types of Levitin-Polyak well-posedness we argue on diameters and Kuratowski’s, Hausdorff’s, or Istrǎtescus measures of noncompactness of approximate solution sets under suitable conditions, and we prove the Levitin-Polyak well-posedness for bilevel vector equilibrium and op...
Czech Academy of Sciences Publication Activity Database
Steiner, Jakub
-, č. 274 (2005), s. 1-26 ISSN 1211-3298 Institutional research plan: CEZ:AV0Z70850503 Keywords : coordination * crises * cycles and fluctuations Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp274.pdf
DEFF Research Database (Denmark)
Geert Jensen, Birgitte; Nielsen, Tom
2013-01-01
og Interaktions Design, Aarhus Universitet under opgave teamet: ”Happy Cycling City – Aarhus”. Udfordringen i studieopgaven var at vise nye attraktive løsningsmuligheder i forhold til cyklens og cyklismens integration i byrum samt at påpege relationen mellem design og overordnede diskussioner af...
Czech Academy of Sciences Publication Activity Database
Steiner, Jakub
2008-01-01
Roč. 63, č. 1 (2008), s. 308-327 ISSN 0899-8256 Institutional research plan: CEZ:AV0Z70850503 Keywords : global games * coordination * crises * cycles and fluctuations Subject RIV: AH - Economics Impact factor: 1.333, year: 2008
Energy Technology Data Exchange (ETDEWEB)
Zu, Tiejun, E-mail: tiejun@mail.xjtu.edu.cn; Wu, Hongchun; Zheng, Youqi; Cao, Liangzhi
2015-01-15
Highlights: • Economics analysis of fuel cycle cost of FFHRs is carried out. • The mass flows of different fuel cycle strategies are established based on the equilibrium fuel cycle model. • The levelized fuel cycle costs of different fuel cycle strategies are calculated, and compared with current once-through fuel cycle. - Abstract: The economics analysis of fuel cycle cost of fusion–fission hybrid reactors has been performed to compare four fuel cycle strategies: light water cooled blanket burning natural uranium (Strategy A) or spent nuclear fuel (Strategy B), sodium cooled blanket burning transuranics (Strategy C) or minor actinides (Strategy D). The levelized fuel cycle costs (LFCC) which does not include the capital cost, operation and maintenance cost have been calculated based on the equilibrium mass flows. The current once-through (OT) cycle strategy has also been analyzed to serve as the reference fuel cycle for comparisons. It is found that Strategy A and Strategy B have lower LFCCs than OT cycle; although the LFCC of Strategy C is higher than that of OT cycle when the uranium price is at its nominal value, it would become comparable to that of OT cycle when the uranium price reaches its historical peak value level; Strategy D shows the highest LFCC, because it needs to reprocess huge mass of spent nuclear fuel; LFCC is sensitive to the discharge burnup of the nuclear fuel.
Equilibrium 𝛽-limits in classical stellarators
Loizu, J.; Hudson, S. R.; Nührenberg, C.; Geiger, J.; Helander, P.
2017-12-01
A numerical investigation is carried out to understand the equilibrium -limit in a classical stellarator. The stepped-pressure equilibrium code (Hudson et al., Phys. Plasmas, vol. 19 (11), 2012) is used in order to assess whether or not magnetic islands and stochastic field-lines can emerge at high . Two modes of operation are considered: a zero-net-current stellarator and a fixed-iota stellarator. Despite the fact that relaxation is allowed (Taylor, Rev. Mod. Phys., vol. 58 (3), 1986, pp. 741-763), the former is shown to maintain good flux surfaces up to the equilibrium -limit predicted by ideal-magnetohydrodynamics (MHD), above which a separatrix forms. The latter, which has no ideal equilibrium -limit, is shown to develop regions of magnetic islands and chaos at sufficiently high , thereby providing a `non-ideal -limit'. Perhaps surprisingly, however, the value of at which the Shafranov shift of the axis reaches a fraction of the minor radius follows in all cases the scaling laws predicted by ideal-MHD. We compare our results to the High-Beta-Stellarator theory of Freidberg (Ideal MHD, 2014, Cambridge University Press) and derive a new prediction for the non-ideal equilibrium -limit above which chaos emerges.
Aerospace Applications of Non-Equilibrium Plasma
Blankson, Isaiah M.
2016-01-01
Nonequilibrium plasma/non-thermal plasma/cold plasmas are being used in a wide range of new applications in aeronautics, active flow control, heat transfer reduction, plasma-assisted ignition and combustion, noise suppression, and power generation. Industrial applications may be found in pollution control, materials surface treatment, and water purification. In order for these plasma processes to become practical, efficient means of ionization are necessary. A primary challenge for these applications is to create a desired non-equilibrium plasma in air by preventing the discharge from transitioning into an arc. Of particular interest is the impact on simulations and experimental data with and without detailed consideration of non-equilibrium effects, and the consequences of neglecting non-equilibrium. This presentation will provide an assessment of the presence and influence of non-equilibrium phenomena for various aerospace needs and applications. Specific examples to be considered will include the forward energy deposition of laser-induced non-equilibrium plasmoids for sonic boom mitigation, weakly ionized flows obtained from pulsed nanosecond discharges for an annular Hall type MHD generator duct for turbojet energy bypass, and fundamental mechanisms affecting the design and operation of novel plasma-assisted reactive systems in dielectric liquids (water purification, in-pipe modification of fuels, etc.).
Development of a Thermal Equilibrium Prediction Algorithm
International Nuclear Information System (INIS)
Aviles-Ramos, Cuauhtemoc
2002-01-01
A thermal equilibrium prediction algorithm is developed and tested using a heat conduction model and data sets from calorimetric measurements. The physical model used in this study is the exact solution of a system of two partial differential equations that govern the heat conduction in the calorimeter. A multi-parameter estimation technique is developed and implemented to estimate the effective volumetric heat generation and thermal diffusivity in the calorimeter measurement chamber, and the effective thermal diffusivity of the heat flux sensor. These effective properties and the exact solution are used to predict the heat flux sensor voltage readings at thermal equilibrium. Thermal equilibrium predictions are carried out considering only 20% of the total measurement time required for thermal equilibrium. A comparison of the predicted and experimental thermal equilibrium voltages shows that the average percentage error from 330 data sets is only 0.1%. The data sets used in this study come from calorimeters of different sizes that use different kinds of heat flux sensors. Furthermore, different nuclear material matrices were assayed in the process of generating these data sets. This study shows that the integration of this algorithm into the calorimeter data acquisition software will result in an 80% reduction of measurement time. This reduction results in a significant cutback in operational costs for the calorimetric assay of nuclear materials. (authors)
Partial chemical equilibrium in fluid dynamics
International Nuclear Information System (INIS)
Ramshaw, J.D.
1980-01-01
An analysis is given for the flow of a multicomponent fluid in which an arbitrary number of chemical reactions may occur, some of which are in equilibrium while the others proceed kinetically. The primitive equations describing this situation are inconvenient to use because the progress rates omega-dot/sub s/ for the equilibrium reactions are determined implicitly by the associated equilibrium constraint conditions. Two alternative equivalent equation systems that are more pleasant to deal with are derived. In the first system, the omega-dot/sub s/ are eliminated by replacing the transport equations for the chemical species involved in the equilibrium reactions with transport equations for the basic components of which these species are composed. The second system retains the usual species transport equations, but eliminates the nonlinear algebraic equilibrium constraint conditions by deriving an explicit expression for the omega-dot/sub s/. Both systems are specialized to the case of an ideal gas mixture. Considerations involved in solving these equation systems numerically are discussed briefly
Influence of collective excitations on pre-equilibrium and equilibrium processes
International Nuclear Information System (INIS)
Ignatyuk, A.V.; Lunev, V.P.
1990-01-01
The influence of the collective states excitations on equilibrium and preequilibrium processes in reaction is discussed. It is shown that for a consistent description of the contribution of preequilibrium and equilibrium compound processes collective states should be taken into account in the level density calculations. The microscopic and phenomenological approaches for the level density calculations are discussed. 13 refs.; 8 figs
A note on existence of mixed solutions to equilibrium problems with equilibrium constraints
Czech Academy of Sciences Publication Activity Database
Červinka, Michal
2007-01-01
Roč. 2007, č. 24 (2007), s. 27-44 ISSN 1212-074X R&D Projects: GA AV ČR IAA1030405 Institutional research plan: CEZ:AV0Z10750506 Keywords : equilibrium problems with equilibrium constraints * variational analysis * mixed strategy Subject RIV: BA - General Mathematics
Dannhauser, Walter
1980-01-01
Described is an experiment designed to provide an experimental basis for a unifying point of view (utilizing theoretical framework and chemistry laboratory experiments) for physical chemistry students. Three experiments are described: phase equilibrium, chemical equilibrium, and a test of the third law of thermodynamics. (Author/DS)
Non-equilibrium dissipative supramolecular materials with a tunable lifetime
Tena-Solsona, Marta; Rieß, Benedikt; Grötsch, Raphael K.; Löhrer, Franziska C.; Wanzke, Caren; Käsdorf, Benjamin; Bausch, Andreas R.; Müller-Buschbaum, Peter; Lieleg, Oliver; Boekhoven, Job
2017-07-01
Many biological materials exist in non-equilibrium states driven by the irreversible consumption of high-energy molecules like ATP or GTP. These energy-dissipating structures are governed by kinetics and are thus endowed with unique properties including spatiotemporal control over their presence. Here we show man-made equivalents of materials driven by the consumption of high-energy molecules and explore their unique properties. A chemical reaction network converts dicarboxylates into metastable anhydrides driven by the irreversible consumption of carbodiimide fuels. The anhydrides hydrolyse rapidly to the original dicarboxylates and are designed to assemble into hydrophobic colloids, hydrogels or inks. The spatiotemporal control over the formation and degradation of materials allows for the development of colloids that release hydrophobic contents in a predictable fashion, temporary self-erasing inks and transient hydrogels. Moreover, we show that each material can be re-used for several cycles.
Non-Equilibrium Thermodynamics in Multiphase Flows
Mauri, Roberto
2013-01-01
Non-equilibrium thermodynamics is a general framework that allows the macroscopic description of irreversible processes. This book introduces non-equilibrium thermodynamics and its applications to the rheology of multiphase flows. The subject is relevant to graduate students in chemical and mechanical engineering, physics and material science. This book is divided into two parts. The first part presents the theory of non-equilibrium thermodynamics, reviewing its essential features and showing, when possible, some applications. The second part of this book deals with how the general theory can be applied to model multiphase flows and, in particular, how to determine their constitutive relations. Each chapter contains problems at the end, the solutions of which are given at the end of the book. No prior knowledge of statistical mechanics is required; the necessary prerequisites are elements of transport phenomena and on thermodynamics. “The style of the book is mathematical, but nonetheless it remains very re...
Module description of TOKAMAK equilibrium code MEUDAS
Energy Technology Data Exchange (ETDEWEB)
Suzuki, Masaei; Hayashi, Nobuhiko; Matsumoto, Taro; Ozeki, Takahisa [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment
2002-01-01
The analysis of an axisymmetric MHD equilibrium serves as a foundation of TOKAMAK researches, such as a design of devices and theoretical research, the analysis of experiment result. For this reason, also in JAERI, an efficient MHD analysis code has been developed from start of TOKAMAK research. The free boundary equilibrium code ''MEUDAS'' which uses both the DCR method (Double-Cyclic-Reduction Method) and a Green's function can specify the pressure and the current distribution arbitrarily, and has been applied to the analysis of a broad physical subject as a code having rapidity and high precision. Also the MHD convergence calculation technique in ''MEUDAS'' has been built into various newly developed codes. This report explains in detail each module in ''MEUDAS'' for performing convergence calculation in solving the MHD equilibrium. (author)
Computational studies in tokamak equilibrium and transport
International Nuclear Information System (INIS)
Braams, B.J.
1986-01-01
This thesis is concerned with some problems arising in the magnetic confinement approach to controlled thermonuclear fusion. The work address the numerical modelling of equilibrium and transport properties of a confined plasma and the interpretation of experimental data. The thesis is divided in two parts. Part 1 is devoted to some aspects of the MHD equilibrium problem, both in the 'direct' formulation (given an equation for the plasma current, the corresponding equilibrium is to be determined) and in the 'inverse' formulation (the interpretation of measurements at the plasma edge). Part 2 is devoted to numerical studies of the edge plasma. The appropriate Navier-Stokes system of fluid equations is solved in a two-dimensional geometry. The main interest of this work is to develop an understanding of particle and energy transport in the scrape-off layer and onto material boundaries, and also to contribute to the conceptual design of the NET/INTOR tokamak reactor experiment. (Auth.)
Scaling studies of spheromak formation and equilibrium
International Nuclear Information System (INIS)
Geddes, C.G.; Kornack, T.W.; Brown, M.R.
1998-01-01
Formation and equilibrium studies have been performed on the Swarthmore Spheromak Experiment (SSX). Spheromaks are formed with a magnetized coaxial plasma gun and equilibrium is established in both small (d small =0.16 m) and large (d large =3d small =0.50 m) copper flux conservers. Using magnetic probe arrays it has been verified that spheromak formation is governed solely by gun physics (in particular the ratio of gun current to flux, μ 0 I gun /Φ gun ) and is independent of the flux conserver dimensions. It has also been verified that equilibrium is well described by the force free condition ∇xB=λB (λ=constant), particularly early in decay. Departures from the force-free state are due to current profile effects described by a quadratic function λ=λ(ψ). Force-free SSX spheromaks will be merged to study magnetic reconnection in simple magnetofluid structures. copyright 1998 American Institute of Physics
Regret Theory and Equilibrium Asset Prices
Directory of Open Access Journals (Sweden)
Jiliang Sheng
2014-01-01
Full Text Available Regret theory is a behavioral approach to decision making under uncertainty. In this paper we assume that there are two representative investors in a frictionless market, a representative active investor who selects his optimal portfolio based on regret theory and a representative passive investor who invests only in the benchmark portfolio. In a partial equilibrium setting, the objective of the representative active investor is modeled as minimization of the regret about final wealth relative to the benchmark portfolio. In equilibrium this optimal strategy gives rise to a behavioral asset priciting model. We show that the market beta and the benchmark beta that is related to the investor’s regret are the determinants of equilibrium asset prices. We also extend our model to a market with multibenchmark portfolios. Empirical tests using stock price data from Shanghai Stock Exchange show strong support to the asset pricing model based on regret theory.
Non-equilibrium quantum heat machines
Alicki, Robert; Gelbwaser-Klimovsky, David
2015-11-01
Standard heat machines (engine, heat pump, refrigerator) are composed of a system (working fluid) coupled to at least two equilibrium baths at different temperatures and periodically driven by an external device (piston or rotor) sometimes called the work reservoir. The aim of this paper is to go beyond this scheme by considering environments which are stationary but cannot be decomposed into a few baths at thermal equilibrium. Such situations are important, for example in solar cells, chemical machines in biology, various realizations of laser cooling or nanoscopic machines driven by laser radiation. We classify non-equilibrium baths depending on their thermodynamic behavior and show that the efficiency of heat machines powered by them is limited by the generalized Carnot bound.
Relativistic Fluid Dynamics Far From Local Equilibrium
Romatschke, Paul
2018-01-01
Fluid dynamics is traditionally thought to apply only to systems near local equilibrium. In this case, the effective theory of fluid dynamics can be constructed as a gradient series. Recent applications of resurgence suggest that this gradient series diverges, but can be Borel resummed, giving rise to a hydrodynamic attractor solution which is well defined even for large gradients. Arbitrary initial data quickly approaches this attractor via nonhydrodynamic mode decay. This suggests the existence of a new theory of far-from-equilibrium fluid dynamics. In this Letter, the framework of fluid dynamics far from local equilibrium for a conformal system is introduced, and the hydrodynamic attractor solutions for resummed Baier-Romatschke-Son-Starinets-Stephanov theory, kinetic theory in the relaxation time approximation, and strongly coupled N =4 super Yang-Mills theory are identified for a system undergoing Bjorken flow.
Answer Sets in a Fuzzy Equilibrium Logic
Schockaert, Steven; Janssen, Jeroen; Vermeir, Dirk; de Cock, Martine
Since its introduction, answer set programming has been generalized in many directions, to cater to the needs of real-world applications. As one of the most general “classical” approaches, answer sets of arbitrary propositional theories can be defined as models in the equilibrium logic of Pearce. Fuzzy answer set programming, on the other hand, extends answer set programming with the capability of modeling continuous systems. In this paper, we combine the expressiveness of both approaches, and define answer sets of arbitrary fuzzy propositional theories as models in a fuzzification of equilibrium logic. We show that the resulting notion of answer set is compatible with existing definitions, when the syntactic restrictions of the corresponding approaches are met. We furthermore locate the complexity of the main reasoning tasks at the second level of the polynomial hierarchy. Finally, as an illustration of its modeling power, we show how fuzzy equilibrium logic can be used to find strong Nash equilibria.
Module description of TOKAMAK equilibrium code MEUDAS
International Nuclear Information System (INIS)
Suzuki, Masaei; Hayashi, Nobuhiko; Matsumoto, Taro; Ozeki, Takahisa
2002-01-01
The analysis of an axisymmetric MHD equilibrium serves as a foundation of TOKAMAK researches, such as a design of devices and theoretical research, the analysis of experiment result. For this reason, also in JAERI, an efficient MHD analysis code has been developed from start of TOKAMAK research. The free boundary equilibrium code ''MEUDAS'' which uses both the DCR method (Double-Cyclic-Reduction Method) and a Green's function can specify the pressure and the current distribution arbitrarily, and has been applied to the analysis of a broad physical subject as a code having rapidity and high precision. Also the MHD convergence calculation technique in ''MEUDAS'' has been built into various newly developed codes. This report explains in detail each module in ''MEUDAS'' for performing convergence calculation in solving the MHD equilibrium. (author)
Non-equilibrium quantum heat machines
International Nuclear Information System (INIS)
Alicki, Robert; Gelbwaser-Klimovsky, David
2015-01-01
Standard heat machines (engine, heat pump, refrigerator) are composed of a system (working fluid) coupled to at least two equilibrium baths at different temperatures and periodically driven by an external device (piston or rotor) sometimes called the work reservoir. The aim of this paper is to go beyond this scheme by considering environments which are stationary but cannot be decomposed into a few baths at thermal equilibrium. Such situations are important, for example in solar cells, chemical machines in biology, various realizations of laser cooling or nanoscopic machines driven by laser radiation. We classify non-equilibrium baths depending on their thermodynamic behavior and show that the efficiency of heat machines powered by them is limited by the generalized Carnot bound. (paper)
Interfaces at equilibrium: A guide to fundamentals.
Marmur, Abraham
2017-06-01
The fundamentals of the thermodynamics of interfaces are reviewed and concisely presented. The discussion starts with a short review of the elements of bulk thermodynamics that are also relevant to interfaces. It continues with the interfacial thermodynamics of two-phase systems, including the definition of interfacial tension and adsorption. Finally, the interfacial thermodynamics of three-phase (wetting) systems is discussed, including the topic of non-wettable surfaces. A clear distinction is made between equilibrium conditions, in terms of minimizing energies (internal, Gibbs or Helmholtz), and equilibrium indicators, in terms of measurable, intrinsic properties (temperature, chemical potential, pressure). It is emphasized that the equilibrium indicators are the same whatever energy is minimized, if the boundary conditions are properly chosen. Also, to avoid a common confusion, a distinction is made between systems of constant volume and systems with drops of constant volume. Copyright © 2016 Elsevier B.V. All rights reserved.
Approach to chemical equilibrium in thermal models
International Nuclear Information System (INIS)
Boal, D.H.
1984-01-01
The experimentally measured (μ - , charged particle)/(μ - ,n) and (p,n/p,p') ratios for the emission of energetic nucleons are used to estimate the time evolution of a system of secondary nucleons produced in a direct interaction of a projectile or captured muon. The values of these ratios indicate that chemical equilibrium is not achieved among the secondary nucleons in noncomposite induced reactions, and this restricts the time scale for the emission of energetic nucleons to be about 0.7 x 10 -23 sec. It is shown that the reason why thermal equilibrium can be reached so rapidly for a particular nucleon species is that the sum of the particle spectra produced in multiple direct reactions looks surprisingly thermal. The rate equations used to estimate the reaction times for muon and nucleon induced reactions are then applied to heavy ion collisions, and it is shown that chemical equilibrium can be reached more rapidly, as one would expect
International Nuclear Information System (INIS)
Bahm, W.
1989-01-01
The situation of the nuclear fuel cycle for LWR type reactors in France and in the Federal Republic of Germany was presented in 14 lectures with the aim to compare the state-of-the-art in both countries. In addition to the momentarily changing fuilds of fuel element development and fueling strategies, the situation of reprocessing, made interesting by some recent developmnts, was portrayed and differences in ultimate waste disposal elucidated. (orig.) [de
Isotope effects in the equilibrium and non-equilibrium vaporization of tritiated water and ice
International Nuclear Information System (INIS)
Baumgaertner, F.; Kim, M.-A.
1990-01-01
The vaporization isotope effect of the HTO/H 2 O system has been measured at various temperatures and pressures under equilibrium as well as non-equilibrium conditions. The isotope effect values measured in equilibrium sublimation or distillation are in good agreement with the theoretical values based on the harmonic oscillator model. In non-equilibrium vaporization at low temperatures ( 0 C), the isotope effect decreases rapidly with decreasing system pressure and becomes negligible when the system pressure is lowered more than one tenth of the equilibrium vapor pressure. At higher temperatures, the isotope effect decreases very slowly with decreasing system pressure. Discussion is extended for the application of the present results to the study of biological enrichment of tritium. (author)
Equilibrium structure of rare earth trihalides
International Nuclear Information System (INIS)
Oezgueven, Y.
2004-01-01
In this work, we have calculate the equilibrium structure of the yttrium tribromide (YBr 3 ) and its dimer using the interionic force model . In the determination of the model parameters of Y monomer and dimer we use the measured value of the breathing mode of molecular dimer in the pure molecular liquid. We compare our results for the equilibrium structure of molecular dimer namely, the bond lengths and bond angles, with measured values from electron diffraction and with the results of other theoretical calculations. The agreement between calculated and measured spectra frequencies of vibrational modes can be considered as very reasonable
Quantum gambling based on Nash-equilibrium
Zhang, Pei; Zhou, Xiao-Qi; Wang, Yun-Long; Liu, Bi-Heng; Shadbolt, Pete; Zhang, Yong-Sheng; Gao, Hong; Li, Fu-Li; O'Brien, Jeremy L.
2017-06-01
The problem of establishing a fair bet between spatially separated gambler and casino can only be solved in the classical regime by relying on a trusted third party. By combining Nash-equilibrium theory with quantum game theory, we show that a secure, remote, two-party game can be played using a quantum gambling machine which has no classical counterpart. Specifically, by modifying the Nash-equilibrium point we can construct games with arbitrary amount of bias, including a game that is demonstrably fair to both parties. We also report a proof-of-principle experimental demonstration using linear optics.
Asymptotic stability estimates near an equilibrium point
Dumas, H. Scott; Meyer, Kenneth R.; Palacián, Jesús F.; Yanguas, Patricia
2017-07-01
We use the error bounds for adiabatic invariants found in the work of Chartier, Murua and Sanz-Serna [3] to bound the solutions of a Hamiltonian system near an equilibrium over exponentially long times. Our estimates depend only on the linearized system and not on the higher order terms as in KAM theory, nor do we require any steepness or convexity conditions as in Nekhoroshev theory. We require that the equilibrium point where our estimate applies satisfy a type of formal stability called Lie stability.
Entropy and equilibrium via games of complexity
Topsøe, Flemming
2004-09-01
It is suggested that thermodynamical equilibrium equals game theoretical equilibrium. Aspects of this thesis are discussed. The philosophy is consistent with maximum entropy thinking of Jaynes, but goes one step deeper by deriving the maximum entropy principle from an underlying game theoretical principle. The games introduced are based on measures of complexity. Entropy is viewed as minimal complexity. It is demonstrated that Tsallis entropy ( q-entropy) and Kaniadakis entropy ( κ-entropy) can be obtained in this way, based on suitable complexity measures. A certain unifying effect is obtained by embedding these measures in a two-parameter family of entropy functions.
Equilibrium calculations for helical axis stellarators
International Nuclear Information System (INIS)
Hender, T.C.; Carreras, B.A.
1984-04-01
An average method based on a vacuum flux coordinate system is presented. This average method permits the study of helical axis stellarators with toroidally dominated shifts. An ordering is introduced, and to lowest order the toroidally averaged equilibrium equations are reduced to a Grad-Shafranov equation. Also, to lowest order, a Poisson-type equation is obtained for the toroidally varying corrections to the equilibium. By including these corrections, systems that are toroidally dominated, but with significant helical distortion to the equilibrium, may be studied. Numerical solutions of the average method equations are shown to agree well with three-dimensional calculations
Equilibrium distribution function in collisionless systems
International Nuclear Information System (INIS)
Pergamenshchik, V.M.
1988-01-01
Collisionless systems of a large number of N particles interacting by Coulomb forces are widely spread in cosmic and laboratory plasma. A statistical theory of equilibrium state of collisionless Coulomb systems which evolution obeys Vlasov equation is proposed. The developed formalism permits a sequential consideration of such distributed in one-particle six-dimensional phase space of a system and to obtain a simple result: equilibrium distribution function has the form of Fermi-Dirac distribution and doesn't depend on initial state factors
Micro Data and General Equilibrium Models
DEFF Research Database (Denmark)
Browning, Martin; Hansen, Lars Peter; Heckman, James J.
1999-01-01
Dynamic general equilibrium models are required to evaluate policies applied at the national level. To use these models to make quantitative forecasts requires knowledge of an extensive array of parameter values for the economy at large. This essay describes the parameters required for different...... economic models, assesses the discordance between the macromodels used in policy evaluation and the microeconomic models used to generate the empirical evidence. For concreteness, we focus on two general equilibrium models: the stochastic growth model extended to include some forms of heterogeneity...
Thermodynamic equilibrium in relativistic rotating systems
International Nuclear Information System (INIS)
Suen, W.M.; Washington Univ., St. Louis, MO; Young, K.
1988-01-01
The thermodynamic equilibrium configurations of relativistic rotating stars are studied using the maximum entropy principle. It is shown that the heuristic arguments for the equilibrium conditions can be developed into a maximum entropy principle in which the variations are carried out in a fixed background spacetime. This maximum principle with the fixed background assumption is technically simpler than, but has to be justified by, a maximum entropy principle without the assumption. Such a maximum entropy principle is formulated in this paper, showing that the general relativistic system can be treated on the same footing as other long-range force systems. (author)
The empirical equilibrium structure of diacetylene
Thorwirth, S.; Harding, M. E.; Muders, D.; Gauss, J.
2008-01-01
High-level quantum-chemical calculations are reported at the MP2 and CCSD(T) levels of theory for the equilibrium structure and the harmonic and anharmonic force fields of diacetylene, HCCCCH. The calculations were performed employing Dunning's hierarchy of correlation-consistent basis sets cc-pVXZ, cc-pCVXZ, and cc-pwCVXZ, as well as the ANO2 basis set of Almloef and Taylor. An empirical equilibrium structure based on experimental rotational constants for thirteen isotopic species of diacety...
MHD equilibrium of heliotron J plasmas
International Nuclear Information System (INIS)
Suzuki, Yasuhiro; Nakamura, Yuji; Kondo, Katsumi; Nakajima, Noriyoshi; Hayashi, Takaya
2004-01-01
MHD equilibria of Heliotron J plasma are investigated by using HINT code. By assuming some profiles of the current density, effects of the net toroidal currents on the magnetohydrodynamics (MHD) equilibrium are investigated. If the rotational transform can be controlled by the currents, the generation of good flux surfaces is expected. In order to study equilibria with self-consistent bootstrap current, the boozer coordinates are constructed by converged HINT equilibrium as a preliminary study. Obtained spectra are compared with ones of VMEC code and both results are consistent. (author)
Current control necessary for toroidal plasma equilibrium
International Nuclear Information System (INIS)
Nagao, S.
1987-01-01
It is shown that a significant amount of dipole current is necessary for the plasma equilibrium of toroidal configurations in general. Through the vector product with the poloidal field, this dipole current force has to balance with the hoop force of plasma pressure itself of the annular shape. The measurement of such a current of dipole type may be interesting for the confirmation of the plasma equilibrium in the toroidal system. Moreover it is certained that there is a new mode of a tokamak operation with such a dipole current component and with smaller vertical field than that based on the classical tokamak theory. (author) [pt
Algorithm For Hypersonic Flow In Chemical Equilibrium
Palmer, Grant
1989-01-01
Implicit, finite-difference, shock-capturing algorithm calculates inviscid, hypersonic flows in chemical equilibrium. Implicit formulation chosen because overcomes limitation on mathematical stability encountered in explicit formulations. For dynamical portion of problem, Euler equations written in conservation-law form in Cartesian coordinate system for two-dimensional or axisymmetric flow. For chemical portion of problem, equilibrium state of gas at each point in computational grid determined by minimizing local Gibbs free energy, subject to local conservation of molecules, atoms, ions, and total enthalpy. Major advantage: resulting algorithm naturally stable and captures strong shocks without help of artificial-dissipation terms to damp out spurious numerical oscillations.
Computing Properties Of Chemical Mixtures At Equilibrium
Mcbride, B. J.; Gordon, S.
1995-01-01
Scientists and engineers need data on chemical equilibrium compositions to calculate theoretical thermodynamic properties of chemical systems. Information essential in design and analysis of such equipment as compressors, turbines, nozzles, engines, shock tubes, heat exchangers, and chemical-processing equipment. CET93 is general program that calculates chemical equilibrium compositions and properties of mixtures for any chemical system for which thermodynamic data are available. Includes thermodynamic data for more than 1,300 gaseous and condensed species and thermal-transport data for 151 gases. Written in FORTRAN 77.
On financial equilibrium with intermediation costs
DEFF Research Database (Denmark)
Markeprand, Tobias Ejnar
2008-01-01
This paper studies the set of competitive equilibria in financial economies with intermediation costs. We consider an arbitrary dividend structure, which includes options and equity with limited liabilities.We show a general existence result and upper-hemi continuity of the equilibrium correspond......This paper studies the set of competitive equilibria in financial economies with intermediation costs. We consider an arbitrary dividend structure, which includes options and equity with limited liabilities.We show a general existence result and upper-hemi continuity of the equilibrium...
14 CFR 67.205 - Ear, nose, throat, and equilibrium.
2010-01-01
... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Ear, nose, throat, and equilibrium. 67.205..., nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a second-class airman..., vertigo or a disturbance of equilibrium. ...
14 CFR 67.105 - Ear, nose, throat, and equilibrium.
2010-01-01
... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Ear, nose, throat, and equilibrium. 67.105..., nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a first-class airman... may reasonably be expected to be manifested by, vertigo or a disturbance of equilibrium. ...
14 CFR 67.305 - Ear, nose, throat, and equilibrium.
2010-01-01
... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Ear, nose, throat, and equilibrium. 67.305..., nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a third-class airman... by, or that may reasonably be expected to be manifested by, vertigo or a disturbance of equilibrium. ...
46 CFR 42.20-12 - Conditions of equilibrium.
2010-10-01
... 46 Shipping 2 2010-10-01 2010-10-01 false Conditions of equilibrium. 42.20-12 Section 42.20-12... BY SEA Freeboards § 42.20-12 Conditions of equilibrium. The following conditions of equilibrium are... stability. Through an angle of 20 degrees beyond its position of equilibrium, the vessel must meet the...
Statistical equilibrium equations for trace elements in stellar atmospheres
Kubat, Jiri
2010-01-01
The conditions of thermodynamic equilibrium, local thermodynamic equilibrium, and statistical equilibrium are discussed in detail. The equations of statistical equilibrium and the supplementary equations are shown together with the expressions for radiative and collisional rates with the emphasize on the solution for trace elements.
Hughes, J T; Barzi, F; Hoy, W E; Jones, G R D; Rathnayake, G; Majoni, S W; Thomas, M A B; Sinha, A; Cass, A; MacIsaac, R J; O'Dea, K; Maple-Brown, L J
2017-12-01
Low serum bilirubin concentrations are reported to be strongly associated with cardio-metabolic disease, but this relationship has not been reported among Indigenous Australian people who are known to be at high risk for diabetes and chronic kidney disease (CKD). serum bilirubin will be negatively associated with markers of chronic disease, including CKD and anaemia among Indigenous Australians. A cross-sectional analysis of 594 adult Aboriginal and Torres Strait Islander (TSI) people in good health or with diabetes and markers of CKD. Measures included urine albumin: creatinine ratio (ACR), estimated glomerular filtration rate (eGFR), haemoglobin (Hb) and glycated haemoglobin (HbA1c). Diabetes was defined by medical history, medications or HbA1c≥6.5% or ≥48mmol/mol. Anaemia was defined as Hbbilirubin was performed. Participants mean (SD) age was 45.1 (14.5) years, and included 62.5% females, 71.7% Aboriginal, 41.1% with diabetes, 16.7% with anaemia, 41% with ACR>3mg/mmol and 18.2% with eGFRbilirubin concentration was lower in females than males (6 v 8μmol/L, pbilirubin; Hb and cholesterol (both positively related) and ACR, triglycerides, Aboriginal ethnicity and female gender (all inversely related). Serum bilirubin concentrations were positively associated with Hb and total cholesterol, and inversely associated with ACR. Further research to determine reasons explaining lower bilirubin concentrations among Aboriginal compared with TSI participants are needed. Copyright © 2017 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.
Contribution to the study of the conversion PWR type reactors to the thorium cycle
International Nuclear Information System (INIS)
Martins Filho, J.R.
1980-01-01
The use of the thorium cycle in PWR reactors is discussed. The fuel has been calculated in the equilibrium condition for a economic comparison with the uranium cycle (in the same condition). First of all, a code named EQUILIBRIO has been developed for the fuel equilibrium calculation. The results gotten by this code, were introduced in the LEOPARD code for the fuel depletion calculation (in the equilibrium cycle). Same important physics details of fuel depletion are studied, for instance: the neutron balance, power sharing, fuel burnup, etc. The calculations have been done taking as reference the Angra-1 PWR reactor. (Author) [pt
HINT computation of LHD equilibrium with zero rotational transform surface
International Nuclear Information System (INIS)
Kanno, Ryutaro; Toi, Kazuo; Watanabe, Kiyomasa; Hayashi, Takaya; Miura, Hideaki; Nakajima, Noriyoshi; Okamoto Masao
2004-01-01
A Large Helical Device equilibrium having a zero rotational transform surface is studied by using the three dimensional MHD equilibrium code, HINT. We find existence of the equilibrium but with formation of the two or three n=0 islands composing a homoclinic-type structure near the center, where n is a toroidal mode number. The LHD equilibrium maintains the structure, when the equilibrium beta increases. (author)
A New Dynamic Model for Nuclear Fuel Cycle System Analysis
International Nuclear Information System (INIS)
Choi, Sungyeol; Ko, Won Il
2014-01-01
The evaluation of mass flow is a complex process where numerous parameters and their complex interaction are involved. Given that many nuclear power countries have light and heavy water reactors and associated fuel cycle technologies, the mass flow analysis has to consider a dynamic transition from the open fuel cycle to other cycles over decades or a century. Although an equilibrium analysis provides insight concerning the end-states of fuel cycle transitions, it cannot answer when we need specific management options, whether the current plan can deliver these options when needed, and how fast the equilibrium can be achieved. As a pilot application, the government brought several experts together to conduct preliminary evaluations for nuclear fuel cycle options in 2010. According to Table 1, they concluded that the closed nuclear fuel cycle has long-term advantages over the open fuel cycle. However, it is still necessary to assess these options in depth and to optimize transition paths of these long-term options with advanced dynamic fuel cycle models. A dynamic simulation model for nuclear fuel cycle systems was developed and its dynamic mass flow analysis capability was validated against the results of existing models. This model can reflects a complex combination of various fuel cycle processes and reactor types, from once-through to multiple recycling, within a single nuclear fuel cycle system. For the open fuel cycle, the results of the developed model are well matched with the results of other models
Equilibrium and off-equilibrium trap-size scaling in one-dimensional ultracold bosonic gases
International Nuclear Information System (INIS)
Campostrini, Massimo; Vicari, Ettore
2010-01-01
We study some aspects of equilibrium and off-equilibrium quantum dynamics of dilute bosonic gases in the presence of a trapping potential. We consider systems with a fixed number of particles and study their scaling behavior with increasing the trap size. We focus on one-dimensional bosonic systems, such as gases described by the Lieb-Liniger model and its Tonks-Girardeau limit of impenetrable bosons, and gases constrained in optical lattices as described by the Bose-Hubbard model. We study their quantum (zero-temperature) behavior at equilibrium and off equilibrium during the unitary time evolution arising from changes of the trapping potential, which may be instantaneous or described by a power-law time dependence, starting from the equilibrium ground state for an initial trap size. Renormalization-group scaling arguments and analytical and numerical calculations show that the trap-size dependence of the equilibrium and off-equilibrium dynamics can be cast in the form of a trap-size scaling in the low-density regime, characterized by universal power laws of the trap size, in dilute gases with repulsive contact interactions and lattice systems described by the Bose-Hubbard model. The scaling functions corresponding to several physically interesting observables are computed. Our results are of experimental relevance for systems of cold atomic gases trapped by tunable confining potentials.
Equilibrium-constant expressions for aqueous plutonium
International Nuclear Information System (INIS)
Silver, G.L.
2010-01-01
Equilibrium-constant expressions for Pu disproportionation reactions traditionally contain three or four terms representing the concentrations or fractions of the oxidation states. The expressions can be rewritten so that one of the oxidation states is replaced by a term containing the oxidation number of the plutonium. Experimental estimations of the numerical values of the constants can then be checked in several ways. (author)
On the Existence of Evolutionary Learning Equilibriums
Directory of Open Access Journals (Sweden)
Masudul Alam Choudhury
2011-12-01
Full Text Available The usual kinds of Fixed-Point Theorems formalized on the existence of competitive equilibrium that explain much of economic theory at the core of economics can operate only on bounded and closed sets with convex mappings. But these conditions are hardly true of the real world of economic and financial complexities and perturbations. The category of learning sets explained by continuous fields of interactive, integrative and evolutionary behaviour caused by dynamic preferences at the individual and institutional and social levels cannot maintain the assumption of closed, bounded and convex sets. Thus learning sets and multi-system inter-temporal relations explained by pervasive complementarities and participation between variables and entities, and evolution by learning, have evolutionary equilibriums. Such a study requires a new methodological approach. This paper formalizes such a methodology for evolutionary equilibriums in learning spaces. It briefly points out the universality of learning equilibriums in all mathematical structures. For a particular case though, the inter-systemic interdependence between sustainable development and ethics and economics in the specific understanding of learning domain is pointed out.
Conditions for the Existence of Market Equilibrium.
Bryant, William D. A.
1997-01-01
Maintains that most graduate-level economics textbooks rarely mention the need for consumers to be above their minimum wealth position as a condition for market equilibrium. Argues that this omission leaves students with a mistaken sense about the range of circumstances under which market equilibria can exist. (MJP)
General Equilibrium Models: Improving the Microeconomics Classroom
Nicholson, Walter; Westhoff, Frank
2009-01-01
General equilibrium models now play important roles in many fields of economics including tax policy, environmental regulation, international trade, and economic development. The intermediate microeconomics classroom has not kept pace with these trends, however. Microeconomics textbooks primarily focus on the insights that can be drawn from the…
Equilibrium thermodynamics in modified gravitational theories
International Nuclear Information System (INIS)
Bamba, Kazuharu; Geng, C.-Q.; Tsujikawa, Shinji
2010-01-01
We show that it is possible to obtain a picture of equilibrium thermodynamics on the apparent horizon in the expanding cosmological background for a wide class of modified gravity theories with the Lagrangian density f(R,φ,X), where R is the Ricci scalar and X is the kinetic energy of a scalar field φ. This comes from a suitable definition of an energy-momentum tensor of the 'dark' component that respects to a local energy conservation in the Jordan frame. In this framework the horizon entropy S corresponding to equilibrium thermodynamics is equal to a quarter of the horizon area A in units of gravitational constant G, as in Einstein gravity. For a flat cosmological background with a decreasing Hubble parameter, S globally increases with time, as it happens for viable f(R) inflation and dark energy models. We also show that the equilibrium description in terms of the horizon entropy S is convenient because it takes into account the contribution of both the horizon entropy S in non-equilibrium thermodynamics and an entropy production term.
Non-equilibrium thermodynamics and physical kinetics
Bikkin, Halid
2014-01-01
This graduate textbook covers contemporary directions of non-equilibrium statistical mechanics as well as classical methods of kinetics. With one of the main propositions being to avoid terms such as "obviously" and "it is easy to show", this treatise is an easy-to-read introduction into this traditional, yet vibrant field.
Pre-equilibrium complex particle emission
International Nuclear Information System (INIS)
Bĕták, E.
2002-01-01
Semi-classical (phenomenological) pre-equilibrium emission of clusters of nucleons (complex particles) such as deuterons, tritons, helions and α particles from reactions induced by light projectiles (nucleons to α’s) is addressed. The main attention is given to the hard components in the emission energetic spectra, which play an increasing role at incident energies above 20 MeV, and are currently attributed to a presence of some kind of pre-equilibrium processes. In addition, the mechanisms of cluster reactions show special features such as the competition between pickup and knockout processes and the contributions of several successive steps in the reaction. The main frame used here to illustrate the processes and interplays of the competing mechanisms of pre-equilibrium cluster formation and emission, namely the coalescence, pick-up and knock-out, is the pre-equilibrium exciton model. It obviously contains the process of clusterization itself as its organic part. The most important case of complex particles with the largest amount of experimental data is that of alpha emission, which therefore naturally attracts most of the attention and where the widest range of possible mechanisms is available on the market. The loosely bound ejectiles, on the other side, are usually not able to demonstrate all features of the whole spectrum of contributing mechanisms, but they are nevertheless an important link between the nucleon emission and the cluster one.
Economic Equilibrium and Soviet Economic Reform
Herbert E. Scarf
1991-01-01
The paper, prepared for a Roundtable on Major Economic Problems in the U.S. and the U.S.S.R., discusses some aspects of price theory ñ in particular, the theory of general equilibrium -ñ which may offer some theoretical insights about the economic problems to be encountered during the transition from Socialism to private markets in the Soviet Union.
Tenancy and Soil Conservation in Market Equilibrium
Lichtenberg, Erik
2001-01-01
A theoretical analysis of equilibrium contracts between risk neutral landlords and tenants when tenants' soil exploitation is non-contractible indicates that landlords will overinvest in conservation structures. An empirical model using farm-level data provides evidence that investment in contractible soil conservation measures is greater on rental land.
Climate change as (dis)equilibrium
DEFF Research Database (Denmark)
Tejsner, Pelle; Veldhuis, Djuke
2018-01-01
Despite the evident challenges posed by arctic environments past and present, and despite the widespread acknowledgement that human population histories in the Arctic have historically been quite dynamic, it is often assumed that traditional pre-colonial populations were in perfect equilibrium wi...
Stability and equilibrium in quantum statistical mechanics
International Nuclear Information System (INIS)
Kastler, Daniel.
1975-01-01
A derivation of the Gibbs Ansatz, base of the equilibrium statistical mechanics is provided from a stability requirements, in technical connection with the harmonic analysis of non-commutative dynamical systems. By the same token a relation is established between stability and the positivity of Hamiltonian in the zero temperature case [fr
Equilibrium capillary forces with atomic force microscopy
Sprakel, J.H.B.; Besseling, N.A.M.; Leermakers, F.A.M.; Cohen Stuart, M.A.
2007-01-01
We present measurements of equilibrium forces resulting from capillary condensation. The results give access to the ultralow interfacial tensions between the capillary bridge and the coexisting bulk phase. We demonstrate this with solutions of associative polymers and an aqueous mixture of gelatin
A Progression of Static Equilibrium Laboratory Exercises
Kutzner, Mickey; Kutzner, Andrew
2013-01-01
Although simple architectural structures like bridges, catwalks, cantilevers, and Stonehenge have been integral in human societies for millennia, as have levers and other simple tools, modern students of introductory physics continue to grapple with Newton's conditions for static equilibrium. As formulated in typical introductory physics…
Can elliptical galaxies be equilibrium systems
Energy Technology Data Exchange (ETDEWEB)
Caimmi, R [Padua Univ. (Italy). Ist. di Astronomia
1980-08-01
This paper deals with the question of whether elliptical galaxies can be considered as equilibrium systems (i.e., the gravitational + centrifugal potential is constant on the external surface). We find that equilibrium models such as Emden-Chandrasekhar polytropes and Roche polytropes with n = 0 can account for the main part of observations relative to the ratio of maximum rotational velocity to central velocity dispersion in elliptical systems. More complex models involving, for example, massive halos could lead to a more complete agreement. Models that are a good fit to the observed data are characterized by an inner component (where most of the mass is concentrated) and a low-density outer component. A comparison is performed between some theoretical density distributions and the density distribution observed by Young et al. (1978) in NGC 4473, but a number of limitations must be adopted. Alternative models, such as triaxial oblate non-equilibrium configurations with coaxial shells, involve a number of problems which are briefly discussed. We conclude that spheroidal oblate models describing elliptical galaxies cannot be ruled out until new analyses relative to more refined theoretical equilibrium models (involving, for example, massive halos) and more detailed observations are performed.
Equilibrium Selection in Games with Macroeconomic Complementarities
Kaarboe, Oddvar M.; Tieman, Alexander F.
1999-01-01
We apply the stochastic evolutionary approach of equilibrium selection tomacroeconomic models in which a complementarity at the macro level ispresent. These models often exhibit multiple Pareto-ranked Nash equilibria,and the best response-correspondence of an individual increases with ameasure of
Static Equilibrium Configurations of Charged Metallic Bodies ...
African Journals Online (AJOL)
In this paper we developed a simple numerical scheme to determine the static equilibrium configuration of charged metallic bodies by minimizing the potential energy function. The method developed has some advantages; it combines the general theory and the physical meanings nested in the mathematical model and this ...
Line radiative transfer and statistical equilibrium
Kamp, Inga
Atomic and molecular line emission from protoplanetary disks contains key information of their detailed physical and chemical structures. To unravel those structures, we need to understand line radiative transfer in dusty media and the statistical equilibrium, especially of molecules. I describe
Plasma equilibrium and stability in stellarators
International Nuclear Information System (INIS)
Pustovitov, V.D.; Shafranov, V.D.
1987-01-01
A review of theoretical methods of investigating plasma equilibrium and stability in stellarators is given. Principles forming the basis of toroidal plasma equilibrium and its stabilization, and the main results of analytical theory and numerical calculations are presented. Configurations with spiral symmetry and usual stellarators with plane axis and spiral fields are considered in detail. Derivation of scalar two-dimensional equations, describing equilibrium in these systems is given. These equations were used to obtain one-dimensional equations for displacement and ellipticity of magnetic surfaces. The model of weak-elliptic displaced surfaces was used to consider the evolution of plasma equilibrium in stellarators after elevation of its pressure: change of profile of rotational transformation after change of plasma pressure, current generation during its fast heating and its successive damping due to finite plasma conductivity were described. The derivation of equations of small oscillations in the form, suitable for local disturbance investigation is presented. These equations were used to obtain Mercier criteria and ballon model equations. General sufficient conditions of plasma stability in systems with magnetic confinement were derived
Estimating Equilibrium Effects of Job Search Assistance
DEFF Research Database (Denmark)
Gautier, Pieter; Muller, Paul; van der Klaauw, Bas
that the nonparticipants in the experiment regions find jobs slower after the introduction of the activation program (relative to workers in other regions). We then estimate an equilibrium search model. This model shows that a large scale role out of the activation program decreases welfare, while a standard partial...... microeconometric cost-benefit analysis would conclude the opposite....
Calculating Shocks In Flows At Chemical Equilibrium
Eberhardt, Scott; Palmer, Grant
1988-01-01
Boundary conditions prove critical. Conference paper describes algorithm for calculation of shocks in hypersonic flows of gases at chemical equilibrium. Although algorithm represents intermediate stage in development of reliable, accurate computer code for two-dimensional flow, research leading up to it contributes to understanding of what is needed to complete task.
Teaching Chemical Equilibrium with the Jigsaw Technique
Doymus, Kemal
2008-01-01
This study investigates the effect of cooperative learning (jigsaw) versus individual learning methods on students' understanding of chemical equilibrium in a first-year general chemistry course. This study was carried out in two different classes in the department of primary science education during the 2005-2006 academic year. One of the classes…
Evolution and non-equilibrium physics
DEFF Research Database (Denmark)
Becker, Nikolaj; Sibani, Paolo
2014-01-01
We argue that the stochastic dynamics of interacting agents which replicate, mutate and die constitutes a non-equilibrium physical process akin to aging in complex materials. Specifically, our study uses extensive computer simulations of the Tangled Nature Model (TNM) of biological evolution...
Wang, Zhijian; Xu, Bin; Zhejiang Collaboration
2011-03-01
In social science, laboratory experiment with human subjects' interaction is a standard test-bed for studying social processes in micro level. Usually, as in physics, the processes near equilibrium are suggested as stochastic processes with time-reversal symmetry (TRS). To the best of our knowledge, near equilibrium, the breaking time symmetry, as well as the existence of robust time anti-symmetry processes, has not been reported clearly in experimental economics till now. By employing Markov transition method to analysis the data from human subject 2x2 Games with wide parameters and mixed Nash equilibrium, we study the time symmetry of the social interaction process near Nash equilibrium. We find that, the time symmetry is broken, and there exists a robust time anti-symmetry processes. We also report the weight of the time anti-symmetry processes in the total processes of each the games. Evidences in laboratory marketing experiments, at the same time, are provided as one-dimension cases. In these cases, time anti-symmetry cycles can also be captured. The proposition of time anti-symmetry processes is small, but the cycles are distinguishable.
Comparative study on plutonium and MA recycling in equilibrium burnup and standard burnup of PWR
International Nuclear Information System (INIS)
Waris, Abdul; Kurniadi, Rizal; Su'ud, Zaki; Permana, Sidik
2005-01-01
The equilibrium burnup model is a powerful method since its can handle all possible generated nuclides in any nuclear system. Moreover, this method is a simple time independent method. Hence the equilibrium burnup method could be very useful for evaluating and forecasting the characteristics of any nuclear fuel cycle, even the strange one, e.g. all nuclides are confined in the reactor. However, this method needs to be verified since the method is not a standard tool. The present study aimed to compare the characteristics of plutonium recycling and plutonium and minor actinides (MA) recycling in PWR with the equilibrium burnup and the standard burnup. In order to become more comprehensive study, an influence of moderator-to-fuel volume ratio (MFR) changes by changing the pin-pitch of fuel cell has been evaluated. The MFR ranges from 0.5 to 4.0. For the equilibrium burnup we used equilibrium cell-burnup code. We have employed 1368 nuclides in the equilibrium calculation with 129 of them are heavy metals (HMs). For standard burnup, SRAC2002 code has been utilized with 26 HMs and 66 fission products (FPs). The JENDL 3.2 library has been employed for both burnup schemes. The uranium, plutonium and MA vector, which resulted from the equilibrium burnup are directly used as fuel input composition for the standard burnup calculation. Both burnup results demonstrate that plutonium recycling and plutonium and MA recycling can be conducted safer in tight lattice core. They are also show the similar trend in neutron spectrum, which become harder with the increasing number of recycled heavy nuclides as well as the decreasing of the MFR values. However, there are some discrepancy on the effective multiplication factor and the conversion ratio, especially for the reactor core for MFR ≥ 2.0. (author)
Equilibrium Bird Species Diversity in Atlantic Islands.
Valente, Luis; Illera, Juan Carlos; Havenstein, Katja; Pallien, Tamara; Etienne, Rampal S; Tiedemann, Ralph
2017-06-05
Half a century ago, MacArthur and Wilson proposed that the number of species on islands tends toward a dynamic equilibrium diversity around which species richness fluctuates [1]. The current prevailing view in island biogeography accepts the fundamentals of MacArthur and Wilson's theory [2] but questions whether their prediction of equilibrium can be fulfilled over evolutionary timescales, given the unpredictable and ever-changing nature of island geological and biotic features [3-7]. Here we conduct a complete molecular phylogenetic survey of the terrestrial bird species from four oceanic archipelagos that make up the diverse Macaronesian bioregion-the Azores, the Canary Islands, Cape Verde, and Madeira [8, 9]. We estimate the times at which birds colonized and speciated in the four archipelagos, including many previously unsampled endemic and non-endemic taxa and their closest continental relatives. We develop and fit a new multi-archipelago dynamic stochastic model to these data, explicitly incorporating information from 91 taxa, both extant and extinct. Remarkably, we find that all four archipelagos have independently achieved and maintained a dynamic equilibrium over millions of years. Biogeographical rates are homogeneous across archipelagos, except for the Canary Islands, which exhibit higher speciation and colonization. Our finding that the avian communities of the four Macaronesian archipelagos display an equilibrium diversity pattern indicates that a diversity plateau may be rapidly achieved on islands where rates of in situ radiation are low and extinction is high. This study reveals that equilibrium processes may be more prevalent than recently proposed, supporting MacArthur and Wilson's 50-year-old theory. Copyright © 2017 Elsevier Ltd. All rights reserved.
Standardization of 125 Sb in equilibrium non-equilibrium situations with 125m Te
International Nuclear Information System (INIS)
Rodriguez Barquero, L.; Jimenez de Mingo, A.; Grau Carles, A.
1997-10-01
We study the stability of ''125 Sb in the following scintillators: HiSafeIII''TM, Insta- Gel reg s ign Plus and '' Ultima-Gold'' TM. Since ''125 m Te requires more than one year to reach the secular equilibrium with ''125 Sb, we cannot be sure, for a given sample, whether equilibrium is reached or not. In this report we present a new procedure that permits one calibrate mixtures of ''125 Sb+''125 m Te out of the equilibrium. The steps required for the radiochemical separation of the components are indicated. Finally, we study the evolution of counting rate when column yields are less than 100%. (Author)
Two-proton correlation functions for equilibrium and non-equilibrium emission
International Nuclear Information System (INIS)
Gong, W.G.; Gelbke, C.K.; Carlin, N.; De Souza, R.T.; Kim, Y.D.; Lynch, W.G.; Murakami, T.; Poggi, G.; Sanderson, D.; Tsang, M.B.; Xu, H.M.; Michigan State Univ., East Lansing; Fields, D.E.; Kwiatkowski, K.; Planeta, R.; Viola, V.E. Jr.; Yennello, S.J.; Indiana Univ., Bloomington; Indiana Univ., Bloomington; Pratt, S.
1990-01-01
Two-proton correlation functions are compared for equilibrium and non-equilibrium emission processes investigated, respectively, in ''reverse kinematics'' for the reactions 129 Xe+ 27 Al and 129 Xe+ 122 Sn at E/A=31 MeV and in ''forward kinematics'' for the reaction 14 N+ 197 Au at E/A=75 MeV. Observed differences in the shapes of the correlation functions are understood in terms of the different time scales for equilibrium and preequilibrium emission. Transverse and longitudinal correlation functions are very similar. (orig.)
Equilibrium and out-of-equilibrium thermodynamics in supercooled liquids and glasses
International Nuclear Information System (INIS)
Mossa, S; Nave, E La; Tartaglia, P; Sciortino, F
2003-01-01
We review the inherent structure thermodynamical formalism and the formulation of an equation of state (EOS) for liquids in equilibrium based on the (volume) derivatives of the statistical properties of the potential energy surface. We also show that, under the hypothesis that during ageing the system explores states associated with equilibrium configurations, it is possible to generalize the proposed EOS to out-of-equilibrium (OOE) conditions. The proposed formulation is based on the introduction of one additional parameter which, in the chosen thermodynamic formalism, can be chosen as the local minimum where the slowly relaxing OOE liquid is trapped
Anaïs Schaeffer
2012-01-01
The HSE Unit will be running a cycling safety campaign at the entrances to CERN's restaurants on 14, 15 and 16 May. Pop along to see if they can persuade you to get back in the saddle! With summer on its way, you might feel like getting your bike out of winter storage. Well, the HSE Unit has come up with some original ideas to remind you of some of the most basic safety rules. This year, the prevention campaign will be focussing on three themes: "Cyclists and their equipment", "The bicycle on the road", and "Other road users". This is an opportunity to think about the condition of your bike as well as how you ride it. From 14 to 16 May, representatives of the Swiss Office of Accident Prevention and the Touring Club Suisse will join members of the HSE Unit at the entrances to CERN's restaurants to give you advice on safe cycling (see box). They will also be organising three activity stands where you can test your knowle...
International Nuclear Information System (INIS)
Kappernman, J.G.; Albertson, V.D.
1991-01-01
This paper reports that for many electric utility systems, Solar Cycle 22 has been the first introduction to the phenomena of Geomagnetic Disturbances and the disrupting and damaging effects that they can have upon modern power systems. For all intents and purposes, Power Industry awareness of Cycle 22 started with a bang during the Great Geomagnetic Storm of March 13, 1989. This storm caused a blackout to the entire Province of Quebec, permanently damaged a large nuclear plant GSU transformer in New Jersey, and created enough havoc across the entire North American power grid to create the plausible threat of a massive power system blackout. The flurry of activity and investigation that followed has led many engineers to realize that their power systems are indeed vulnerable to this phenomena and if anything are becoming ever more vulnerable as the system grows to meet future requirements. As a result some organizations such as Hydro Quebec, PSE and G, and the PJM Pool now implement strategic measures as a remedial response to detection of geomagnetic storm conditions. Many more companies pay particularly close attention to storm forecasts and alerts, and the industry in general has accelerated research and monitoring activities through their own means of in concert with the Electric Power Research Institute (EPRI)
The cultural divide: exponential growth in classical 2D and metabolic equilibrium in 3D environments
DEFF Research Database (Denmark)
Carvalho, Vasco Botelho
Cellular metabolism can be considered to have two extremes: one is characterized by exponential growth (in 2D cultures) and the other by a dynamic equilibrium (in 3D cultures). We have analysed the proteome and cellular architecture at these two extremes and found that they are dramatically...... different. Ultrastructurally, actin organization is changed, microtubules are increased and keratins 8 and 18 decreased. Metabolically, glycolysis, fatty acid metabolism and the pentose phosphate cycle are increased while Krebs cycle and oxidative phosphorylation is unchanged. Enzymes involved...
The thorium fuel cycle in water-moderated reactor systems
International Nuclear Information System (INIS)
Critoph, E.
1977-05-01
Thorium and uranium cycles are compared with regard to reactor characteristics and technology, fuel-cycle technology, economic parameters, fuel-cycle costs, and system characteristics. In heavy-water reactors (HWRs) thorium cycles having uranium requirements at equilibrium ranging from zero to a quarter of those for the natural-uranium once-through cycle appear feasible. An 'inventory' of uranium of between 1 and 2 Mg/MW(e) is required for the transition to equilibrium. The cycles with the lowest uranium requirements compete with the others only at high uranium prices. Using thorium in light-water reactors, uranium requirements can be reduced by a factor of between two and three from the once-through uranium cycle. The light-water breeder reactor, promising zero uranium requirements at equilibrium, is being developed. Larger uranium inventories are required than for the HWRs. The lead time, from a decision to use thorium to significant impact on uranium utilization (compared to uranium cycle, recycling plutonium) is some two decades
Advanced fuel cycles for WWER-1000 reactors
International Nuclear Information System (INIS)
Semchenkov, Y. M.; Pavlovichev, A. M.; Pavlov, V. I.; Spirkin, E. I.; Styrin, Y. A.; Kosourov, E. K.
2007-01-01
Main stages of Russian uranium fuel development regarding improvement of safety and economics of fuel load operation are presented. Intervals of possible changes in fuel cycle duration have been demonstrated for the use of current and perspective fuel. Examples of equilibrium fuel load patterns have been demonstrated and main core neutronics parameters have been presented. Problems on the use of axial blankets with reduced enrichment in WWER-1000 fuel assemblies are considered. Some results are presented regarding core neutronic characteristics of WWER-1000 at the use of regenerated uranium and uranium-plutonium fuel. Examples of equilibrium fuel cycles for the core partially loaded with MOX fuel from weapon-grade plutonium are also considered (Authors)
Non-equilibrium versus equilibrium emission of complex fragments from hot nuclei
International Nuclear Information System (INIS)
Viola, V.E.; Kwiatkowski, K.; Yennello, S.; Fields, D.E.
1989-01-01
The relative contributions of equilibrium and non-equilibrium mechanisms for intermediate-mass fragment emission have been deduced for Z=3-14 fragments formed in 3 He- and 14 N-induced reactions on Ag and Au targets. Complete inclusive excitation function measurements have been performed for 3 He projectiles from E/A=67 to 1,200 MeV and for 14 N from E/A=20 to 50 MeV. The data are consistent with a picture in which equilibrated emission is important at the lowest energies, but with increasing bombarding energy the cross sections are increasingly dominated by non-equilibrium processes. Non-equilibrium emission is also shown to be favored for light fragments relative to heavy fragments. These results are supported by coincidence studies of intermediate-mass fragments tagged by linear momentum transfer measurements
Non-Equilibrium Heavy Flavored Hadron Yields from Chemical Equilibrium Strangeness-Rich QGP
Kuznetsova, Inga; Rafelski, Johann
2008-01-01
The yields of heavy flavored hadrons emitted from strangeness-rich QGP are evaluated within chemical non-equilibrium statistical hadronization model, conserving strangeness, charm, and entropy yields at hadronization.
International Nuclear Information System (INIS)
Seino, Takeshi; Sekimoto, Hiroshi
1998-01-01
There have been some difficulties in carrying out an extensive evaluation of the equilibrium state of Light Water Reactor (LWR) recycling operations keeping their fixed criticality condition using conventional design codes because of the complexity of their calculation model for practical fuel and core design and because of a large amount of calculation time. This study presents an efficient approach to secure the criticality in an equilibrium cycle by adjusting a supplied fuel composition. The criticality search is performed by the use of fuel importance obtained from the equation adjoint to a continuously fuel supplied core burnup equation. Using this method, some numerical analyses were carried out in order to evaluate the mixed oxide (MOX) fuel composition of equilibrium Boiling Water Reactor (BWR) cores satisfying the criticality requirement. The results showed the comprehensive and quantitative characteristics on the equilibrium cores confining transuraniums for different MOX fuel loading fractions and irradiating conditions
Seasonal thermal energy storage in shallow geothermal systems: thermal equilibrium stage
Directory of Open Access Journals (Sweden)
Nowamooz Hossein
2016-01-01
Full Text Available This paper is dedicated to the study of seasonal heat storage in shallow geothermal installations in unsaturated soils for which hydrothermal properties such as degree of saturation and thermal conductivity vary with time throughout the profile. In the model, a semi-analytical model which estimates time-spatial thermal conductivity is coupled with a 2D cylindrical heat transfer modeling using finite difference method. The variation of temperature was obtained after 3 heating and cooling cycles for the different types of loads with maximum thermal load of qmax = 15 W.m−1 with variable angular frequency (8 months of heating and 4 months of cooling.and constant angular frequency (6 months of heating and 6 months of cooling to estimate the necessary number of cycles to reach the thermal equilibrium stage. The results show that we approach a thermal equilibrium stage where the same variation of temperature can be observed in soils after several heating and cooling cycles. Based on these simulations, the necessary number of cycles can be related to the total applied energy on the system and the minimum number of cycles is for a system with the total applied energy of 1.9qmax.
Machine replacement, Network Externalities and Investment Cycles
Juan Ruiz
2003-01-01
This paper presents a model where agents decide on the timing of replacement of ageing machines. The optimal replacement policy for an agent is influenced by other agents' decisions because the productivity of a particular vintage displays network externalities that set in with a lag. In equilibrium, agents follow innovation cycles with a frequency that is lower than optimal, so there is too much delay. One extreme case is the possibility of inefficient collapse: for some parameters there is ...
A BWR 24-month cycle analysis using multicycle techniques
International Nuclear Information System (INIS)
Hartley, K.D.
1993-01-01
Boiling water reactor (BWR) fuel cycle design analyses have become increasingly challenging in the past several years. As utilities continue to seek improved capacity factors, reduced power generation costs, and reduced outage costs, longer cycle lengths and fuel design optimization become important considerations. Accurate multicycle analysis techniques are necessary to determine the viability of fuel designs and cycle operating strategies to meet reactor operating requirements, e.g., meet thermal and reactivity margin constraints, while minimizing overall fuel cycle costs. Siemens Power Corporation (SPC), Nuclear Division, has successfully employed multi-cycle analysis techniques with realistic rodded cycle depletions to demonstrate equilibrium fuel cycle performance in 24-month cycles. Analyses have been performed by a BWR/5 reactor, at both rated and uprated power conditions
Theory of chemical equilibrium in a lattice
International Nuclear Information System (INIS)
Dietrich, K.; Dufour, M.; Balazs, N.L.
1989-01-01
The chemical equilibrium is studied for the reaction A+B↔C, assuming that, initially, the particles B form a lattice and the particles A are statistically distributed on interstices. A mass action law is derived which defines the numbers n A , n B , n C of particles A, B, C in the chemical equilibrium assuming the initial distribution to be known. It predicts a considerably larger number n C of fused particles C compared to the mass action law for the gaseous phase. The result holds for an ordinary as well as for a nuclear lattice. Its possible relevance for the production of proton-rich isotopes in the universe is discussed. (orig.)
Thermal equilibrium during the electroweak phase transition
International Nuclear Information System (INIS)
Tetradis, N.
1991-12-01
The effective potential for the standard model develops a barrier, at temperatures around the electroweak scale, which separates the minimum at zero field and a deeper non-zero minimum. This could create out of equilibrium conditions by inducing the localization of the Higgs field in a metastable state around zero. In this picture vacuum decay would occur through bubble nucleation. I show that there is an upper bound on the Higgs mass for the above scenario to be realized. The barrier must be high enough to prevent thermal fluctuations of the Higgs expectation value from establishing thermal equilibrium between the two minima. The upper bound is estimated to be lower than the experimental lower limit. This is also imposes constraints on extensions of the standard model constructed in order to generate a strongly first order phase transition. (orig.)
Gyrokinetic Magnetohydrodynamics and the Associated Equilibrium
Lee, W. W.; Hudson, S. R.; Ma, C. H.
2017-10-01
A proposed scheme for the calculations of gyrokinetic MHD and its associated equilibrium is discussed related a recent paper on the subject. The scheme is based on the time-dependent gyrokinetic vorticity equation and parallel Ohm's law, as well as the associated gyrokinetic Ampere's law. This set of equations, in terms of the electrostatic potential, ϕ, and the vector potential, ϕ , supports both spatially varying perpendicular and parallel pressure gradients and their associated currents. The MHD equilibrium can be reached when ϕ -> 0 and A becomes constant in time, which, in turn, gives ∇ . (J|| +J⊥) = 0 and the associated magnetic islands. Examples in simple cylindrical geometry will be given. The present work is partially supported by US DoE Grant DE-AC02-09CH11466.
Thermochemical equilibrium modelling of a gasifying process
International Nuclear Information System (INIS)
Melgar, Andres; Perez, Juan F.; Laget, Hannes; Horillo, Alfonso
2007-01-01
This article discusses a mathematical model for the thermochemical processes in a downdraft biomass gasifier. The model combines the chemical equilibrium and the thermodynamic equilibrium of the global reaction, predicting the final composition of the producer gas as well as its reaction temperature. Once the composition of the producer gas is obtained, a range of parameters can be derived, such as the cold gas efficiency of the gasifier, the amount of dissociated water in the process and the heating value and engine fuel quality of the gas. The model has been validated experimentally. This work includes a parametric study of the influence of the gasifying relative fuel/air ratio and the moisture content of the biomass on the characteristics of the process and the producer gas composition. The model helps to predict the behaviour of different biomass types and is a useful tool for optimizing the design and operation of downdraft biomass gasifiers
Non-equilibrium effects in the plasmas
International Nuclear Information System (INIS)
Einfeld, D.
1975-01-01
Radial dependences of non-equilibrium effects of a He plasma were studied in a wall-stabilized short-time discharge. The electron density (nsub(e) = 2.5 x 10 22 m -3 ), the electron temperature and the equilibrium shift were determined by calculations of the continuum beam density and the beam densities of one He-I and one He-II line, respectively. In the discharge axis, the overpopulation factors of the ground state of He-I and He-II are about 75. As the distance to the axis increases, they increase for He-I and decrease for He-II. Except for the usual errors of measurement, the overpopulation factors found here correspond to those calculated from the balance equations (Drawin). (orig./AK) [de
Cosmic curvature from de Sitter equilibrium cosmology.
Albrecht, Andreas
2011-10-07
I show that the de Sitter equilibrium cosmology generically predicts observable levels of curvature in the Universe today. The predicted value of the curvature, Ω(k), depends only on the ratio of the density of nonrelativistic matter to cosmological constant density ρ(m)(0)/ρ(Λ) and the value of the curvature from the initial bubble that starts the inflation, Ω(k)(B). The result is independent of the scale of inflation, the shape of the potential during inflation, and many other details of the cosmology. Future cosmological measurements of ρ(m)(0)/ρ(Λ) and Ω(k) will open up a window on the very beginning of our Universe and offer an opportunity to support or falsify the de Sitter equilibrium cosmology.
Analytic and numerical studies of Scyllac equilibrium
International Nuclear Information System (INIS)
Barnes, D.C.; Brackbill, J.U.; Dagazian, R.Y.; Freidberg, J.P.; Schneider, W.; Betancourt, O.; Garabedian, P.
1976-01-01
The results of both numerical and analytic studies of the Scyllac equilibria are presented. Analytic expansions are used to derive equilibrium equations appropriate to noncircular cross sections, and compute the stellarator fields which produce toroidal force balance. Numerical algorithms are used to solve both the equilibrium equations and the full system of dynamical equations in three dimensions. Numerical equilibria are found for both l = 1,0 and l= 1,2 systems. It is found that the stellarator fields which produce equilibria in the l = 1.0 system are larger for diffuse than for sharp boundary plasma profiles, and that the stability of the equilibria depends strongly on the harmonic content of the stellarator fields
Equilibrium reconstruction in stellarators: V3FIT
Energy Technology Data Exchange (ETDEWEB)
Hanson, J.D.; Knowlton, S.F. [Physics Department, Auburn University, Auburn, AL (United States); Hirshman, S.P.; Lazarus, E.A. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Lao, L.L. [General Atomics, San Diego, CA (United States)
2003-07-01
The first section describes a general response function formalism for computing stellarator magnetic diagnostic signals, which is the first step in developing a reconstruction capability. The approach parallels that used in the EFIT two-dimensional (2-D) equilibrium reconstruction code. The second section describes the two codes we have written, V3RFUN and V3POST. V3RFUN computes the response functions for a specified magnetic diagnostic coil, and V3POST uses the response functions calculated by V3RFUN, along with the plasma current information supplied by the equilibrium code VMEC, to compute the expected magnetic diagnostic signals. These two codes are currently being used to design magnetic diagnostic for the NCSX stellarator (at PPPL) and the CTH toroidal hybrid stellarator (at Auburn University). The last section of the paper describes plans for the V3FIT code. (orig.)
The nuclear quantum liquid off equilibrium
International Nuclear Information System (INIS)
Bjoernholm, S.
1986-01-01
Fusion, fission, quasifission and deep inelastic scattering of heavy ions sample the behaviour of the nuclear quantum liquid when it is far from equilibrium. This considerably augments the picture of nuclei obtained on the basis of specific perturbative disturbances of the equilibrium configurations, and from compound nucleus decay. Some peculiar properties of a quantum liquid composed of fermions ( 3 He or nucleons) with a mean free path that exceeds the dimensions of the system are reviewed and discussed in relation to measurements of mass asymmetry relaxation in quasifission. It is concluded that heavy ion reactions are especially well suited for studying quantum liquids in the limit where interactions between the particles and the self-consistent surface dominate the dissipative behaviour and where dissipation-fluctuation correlations are important. (orig.)
Equilibrium vertical field in the TBR Tokamak
International Nuclear Information System (INIS)
Ueta, A.Y.
1985-01-01
An experimental study on the influence of the vertical magnetic field of the TBR tokamak on the stability and equilibrium of plasma column, was done. Magnetic pick-up coils were built to measure plasma current and position, together with active networks, necessary fo the electronic processing of signals. Some measurements were on the space configuration of the vertical field, and on the influence due to the toroidal vessel. From the data obtained it was possible to discuss the influence of the currents induced on the vessel surface, on plasma equilibrium. Theoretical and experimental results of the vertica field, as a function of plasma current were compared, and allowed an evaluation of the plasma kinetic pressure and temperature. (Author) [pt
Equilibrium state of colliding electron beams
Directory of Open Access Journals (Sweden)
R. L. Warnock
2003-10-01
Full Text Available We study a nonlinear integral equation that is a necessary condition on the equilibrium phase-space distribution function of stored, colliding electron beams. It is analogous to the Haïssinski equation, being derived from Vlasov-Fokker-Planck theory, but is quite different in form. The equation is analyzed for the case of the Chao-Ruth model of the beam-beam interaction in 1 degree of freedom, a so-called strong-strong model with nonlinear beam-beam force. We prove the existence of a unique solution, for sufficiently small beam current, by an application of the implicit function theorem. We have not yet proved that this solution is positive, as would be required to establish existence of an equilibrium. There is, however, numerical evidence of a positive solution. We expect that our analysis can be extended to more realistic models.
Equilibrium and stability of a rotating plasma
International Nuclear Information System (INIS)
Janssen, P.A.E.M.
1979-01-01
The author considers the equilibrium and stability of a rotating plasma. The kinetic equations for ions and electrons supplemented with the Maxwell equations and the appropriate boundary conditions are used. Two different models for the rotating plasma are considered: the equilibrium of a 'fast' rotating plasma (Magneto Hydrodynamic ordering) and the stability of a slowly rotating, 'weakly' unstable plasma (Finite Larmor Radius ordering). A striking difference between these orderings is the fact that, regarding the stability of the plasma, for a F.L.R. plasma viscosity effects due to the finite Larmor radius are important, whereas in a M.H.D. plasma they are negligible (at least to the required order). (Auth.)
Poloidal field equilibrium calculations for JET
International Nuclear Information System (INIS)
Khalafallah, A.K.
1976-01-01
The structure of the JET 2D Poloidal Field Analysis Package is discussed. The ability to cope with different plasma current density distributions (skin, flat or peaked), each with a range of Beta poloidal values and varying plasma shapes is a new feature of these calculations. It is possible to construct instant-by-instant pictures of equilibrium configurations for various plasma build up scenarios taking into account the level of flux in the iron core and return limbs. The equilibrium configurations are calculated for two possible sequences of plasma build up. Examples of the magnetic field calculations being carried out under contract to JET at the Rutherford Laboratory, using a 3D code, are also given
On equilibrium charge distribution above dielectric surface
Directory of Open Access Journals (Sweden)
Yu.V. Slyusarenko
2009-01-01
Full Text Available The problem of the equilibrium state of the charged many-particle system above dielectric surface is formulated. We consider the case of the presence of the external attractive pressing field and the case of its absence. The equilibrium distributions of charges and the electric field, which is generated by these charges in the system in the case of ideally plane dielectric surface, are obtained. The solution of electrostatic equations of the system under consideration in case of small spatial heterogeneities caused by the dielectric surface, is also obtained. These spatial inhomogeneities can be caused both by the inhomogeneities of the surface and by the inhomogeneous charge distribution upon it. In particular, the case of the "wavy" spatially periodic surface is considered taking into account the possible presence of the surface charges.
Line radiative transfer and statistical equilibrium*
Directory of Open Access Journals (Sweden)
Kamp Inga
2015-01-01
Full Text Available Atomic and molecular line emission from protoplanetary disks contains key information of their detailed physical and chemical structures. To unravel those structures, we need to understand line radiative transfer in dusty media and the statistical equilibrium, especially of molecules. I describe here the basic principles of statistical equilibrium and illustrate them through the two-level atom. In a second part, the fundamentals of line radiative transfer are introduced along with the various broadening mechanisms. I explain general solution methods with their drawbacks and also specific difficulties encountered in solving the line radiative transfer equation in disks (e.g. velocity gradients. I am closing with a few special cases of line emission from disks: Radiative pumping, masers and resonance scattering.
Instability of quantum equilibrium in Bohm's dynamics.
Colin, Samuel; Valentini, Antony
2014-11-08
We consider Bohm's second-order dynamics for arbitrary initial conditions in phase space. In principle, Bohm's dynamics allows for 'extended' non-equilibrium, with initial momenta not equal to the gradient of phase of the wave function (as well as initial positions whose distribution departs from the Born rule). We show that extended non-equilibrium does not relax in general and is in fact unstable. This is in sharp contrast with de Broglie's first-order dynamics, for which non-standard momenta are not allowed and which shows an efficient relaxation to the Born rule for positions. On this basis, we argue that, while de Broglie's dynamics is a tenable physical theory, Bohm's dynamics is not. In a world governed by Bohm's dynamics, there would be no reason to expect to see an effective quantum theory today (even approximately), in contradiction with observation.
Equilibrium Molecular Thermodynamics from Kirkwood Sampling
Somani, Sandeep; Okamoto, Yuko; Ballard, Andrew J.; Wales, David J.
2015-01-01
We present two methods for barrierless equilibrium sampling of molecular systems based on the recently proposed Kirkwood method (J. Chem. Phys. 2009, 130, 134102). Kirkwood sampling employs low-order correlations among internal coordinates of a molecule for random (or non-Markovian) sampling of the high dimensional conformational space. This is a geometrical sampling method independent of the potential energy surface. The first method is a variant of biased Monte Carlo, wher...
A strictly hyperbolic equilibrium phase transition model
International Nuclear Information System (INIS)
Allaire, G; Faccanoni, G; Kokh, S.
2007-01-01
This Note is concerned with the strict hyperbolicity of the compressible Euler equations equipped with an equation of state that describes the thermodynamical equilibrium between the liquid phase and the vapor phase of a fluid. The proof is valid for a very wide class of fluids. The argument only relies on smoothness assumptions and on the classical thermodynamical stability assumptions, that requires a definite negative Hessian matrix for each phase entropy as a function of the specific volume and internal energy. (authors)
Computational methods for reversed-field equilibrium
International Nuclear Information System (INIS)
Boyd, J.K.; Auerbach, S.P.; Willmann, P.A.; Berk, H.L.; McNamara, B.
1980-01-01
Investigating the temporal evolution of reversed-field equilibrium caused by transport processes requires the solution of the Grad-Shafranov equation and computation of field-line-averaged quantities. The technique for field-line averaging and the computation of the Grad-Shafranov equation are presented. Application of Green's function to specify the Grad-Shafranov equation boundary condition is discussed. Hill's vortex formulas used to verify certain computations are detailed. Use of computer software to implement computational methods is described
A More Practical Method for Explaining Equilibrium
Yi-Jang Yu
2014-01-01
The aim of this study is to suggest a more practical method for explaining market equilibrium in a two-dimensional risk-return world. Its main difference from textbook contents is to define, in both qualitative and quantitative ways, the environment or the system factor and treat it as an endogenous variable. Once the two-dimensional framework that is capable of managing uncertainty and environmental relationship can be reasonably established, a greater number of economic issues can be effect...
Nanostructured energy devices equilibrium concepts and kinetics
Bisquert, Juan
2014-01-01
Due to the pressing needs of society, low cost materials for energy devices have experienced an outstanding development in recent times. In this highly multidisciplinary area, chemistry, material science, physics, and electrochemistry meet to develop new materials and devices that perform required energy conversion and storage processes with high efficiency, adequate capabilities for required applications, and low production cost. Nanostructured Energy Devices: Equilibrium Concepts and Kinetics introduces the main physicochemical principles that govern the operation of energy devices. It inclu
Monetary Policy Frameworks and Real Equilibrium Determinacy
DEFF Research Database (Denmark)
Jensen, Henrik
2002-01-01
In a simple "prototype" model of monetary policymaking, I examine the issue of real equilibrium determinacy under targeting and instrument rules. The former framework involves minimization of a loss function (under discretion or commitment), whereas the latter involves commitment to an interest...... rate rule. While instrument rules only lead to determinacy under certain conditions, the targeting rules under consideration always secure determinacy. Within an extended model, I argue that econometric estimations of nominal interest rate response functions may tell little about the economy...
Structural Stability of Tokamak Equilibrium: Transport Barriers
Energy Technology Data Exchange (ETDEWEB)
Solano, E. R.
2001-07-01
A generalised theory of structural stability of differential equations is introduced and applied to the Grad-Shafranov equation. It is discussed how the formation and loss of transport barrier could be associated with the appearance/disappearance of equilibria. The equilibrium conjecture is presented: transport barriers are associated with locally diamagnetic regions in the plasma, and affected by the paramagnetism of the bootstrap current. (Author) 18 refs.
Flux Jacobian Matrices For Equilibrium Real Gases
Vinokur, Marcel
1990-01-01
Improved formulation includes generalized Roe average and extension to three dimensions. Flux Jacobian matrices derived for use in numerical solutions of conservation-law differential equations of inviscid flows of ideal gases extended to real gases. Real-gas formulation of these matrices retains simplifying assumptions of thermodynamic and chemical equilibrium, but adds effects of vibrational excitation, dissociation, and ionization of gas molecules via general equation of state.
Quasilocal equilibrium condition for black ring
International Nuclear Information System (INIS)
Astefanesei, Dumitru; Rodriguez, Maria J.; Theisen, Stefan
2009-01-01
We use the conservation of the renormalized boundary stress-energy tensor to obtain the equilibrium condition for a general (thin or fat) black ring solution. We also investigate the role of the spatial stress in the thermodynamics of deformation within the quasilocal formalism of Brown and York and discuss the relation with other methods. In particular, we discuss the quantum statistical relation for the unbalanced black ring solution.
Information-theoretic equilibrium and observable thermalization
Anza, Fabio; Vedral, Vlatko
2015-01-01
To understand under which conditions thermodynamics emerges from the microscopic dynamics is the ultimate goal of statistical mechanics. Despite the fact that the theory is more than 100 years old, we are still discussing its foundations and its regime of applicability. A point of crucial importance is the definition of the notion of thermal equilibrium, which is given as the state that maximises the von Neumann entropy. Here we argue that it is necessary to propose a new way of describing th...
Decomposition of thermal-equilibrium states
International Nuclear Information System (INIS)
Gu Lei
2010-01-01
It is shown that a thermal-equilibrium state can be decomposed into a tensor product of the operators in subspaces of single-particle energy. On the basis of this form, a straightforward derivation of the Fermi-Dirac and the Bose-Einstein distribution is performed. The derivation can be generalized for systems with weak interaction to obtain an approximate distribution in momentum.
The Equilibrium Spreading Tension of Pulmonary Surfactant
Dagan, Maayan P.; Hall, Stephen B.
2015-01-01
Monomolecular films at an air/water interface coexist at the equilibrium spreading tension (γe) with the bulk phase from which they form. For individual phospholipids, γe is single-valued, and separates conditions at which hydrated vesicles adsorb from tensions at which overcompressed monolayers collapse. With pulmonary surfactant, isotherms show that monolayers compressed on the surface of bubbles coexist with the three-dimensional collapsed phase over a range of surface tensions. γe therefo...
An Equilibrium Model of User Generated Content
Dae-Yong Ahn; Jason A. Duan; Carl F. Mela
2011-01-01
This paper considers the joint creation and consumption of content on user generated content platforms (e.g., reviews or articles, chat, videos, etc.). On these platforms, users' utilities depend upon the participation of others; hence, users' expectations regarding the participation of others on the site becomes germane to their own involvement levels. Yet these beliefs are often assumed to be fixed. Accordingly, we develop a dynamic rational expectations equilibrium model of joint consumpti...
BINARY NEUTRON STARS IN QUASI-EQUILIBRIUM
International Nuclear Information System (INIS)
Taniguchi, Keisuke; Shibata, Masaru
2010-01-01
Quasi-equilibrium sequences of binary neutron stars are constructed for a variety of equations of state in general relativity. Einstein's constraint equations in the Isenberg-Wilson-Mathews approximation are solved together with the relativistic equations of hydrostationary equilibrium under the assumption of irrotational flow. We focus on unequal-mass sequences as well as equal-mass sequences, and compare those results. We investigate the behavior of the binding energy and total angular momentum along a quasi-equilibrium sequence, the endpoint of sequences, and the orbital angular velocity as a function of time, changing the mass ratio, the total mass of the binary system, and the equation of state of a neutron star. It is found that the orbital angular velocity at the mass-shedding limit can be determined by an empirical formula derived from an analytic estimation. We also provide tables for 160 sequences, which will be useful as a guideline of numerical simulations for the inspiral and merger performed in the near future.
TEA: A CODE CALCULATING THERMOCHEMICAL EQUILIBRIUM ABUNDANCES
Energy Technology Data Exchange (ETDEWEB)
Blecic, Jasmina; Harrington, Joseph; Bowman, M. Oliver, E-mail: jasmina@physics.ucf.edu [Planetary Sciences Group, Department of Physics, University of Central Florida, Orlando, FL 32816-2385 (United States)
2016-07-01
We present an open-source Thermochemical Equilibrium Abundances (TEA) code that calculates the abundances of gaseous molecular species. The code is based on the methodology of White et al. and Eriksson. It applies Gibbs free-energy minimization using an iterative, Lagrangian optimization scheme. Given elemental abundances, TEA calculates molecular abundances for a particular temperature and pressure or a list of temperature–pressure pairs. We tested the code against the method of Burrows and Sharp, the free thermochemical equilibrium code Chemical Equilibrium with Applications (CEA), and the example given by Burrows and Sharp. Using their thermodynamic data, TEA reproduces their final abundances, but with higher precision. We also applied the TEA abundance calculations to models of several hot-Jupiter exoplanets, producing expected results. TEA is written in Python in a modular format. There is a start guide, a user manual, and a code document in addition to this theory paper. TEA is available under a reproducible-research, open-source license via https://github.com/dzesmin/TEA.
Statistical approach to partial equilibrium analysis
Wang, Yougui; Stanley, H. E.
2009-04-01
A statistical approach to market equilibrium and efficiency analysis is proposed in this paper. One factor that governs the exchange decisions of traders in a market, named willingness price, is highlighted and constitutes the whole theory. The supply and demand functions are formulated as the distributions of corresponding willing exchange over the willingness price. The laws of supply and demand can be derived directly from these distributions. The characteristics of excess demand function are analyzed and the necessary conditions for the existence and uniqueness of equilibrium point of the market are specified. The rationing rates of buyers and sellers are introduced to describe the ratio of realized exchange to willing exchange, and their dependence on the market price is studied in the cases of shortage and surplus. The realized market surplus, which is the criterion of market efficiency, can be written as a function of the distributions of willing exchange and the rationing rates. With this approach we can strictly prove that a market is efficient in the state of equilibrium.
TEA: A CODE CALCULATING THERMOCHEMICAL EQUILIBRIUM ABUNDANCES
International Nuclear Information System (INIS)
Blecic, Jasmina; Harrington, Joseph; Bowman, M. Oliver
2016-01-01
We present an open-source Thermochemical Equilibrium Abundances (TEA) code that calculates the abundances of gaseous molecular species. The code is based on the methodology of White et al. and Eriksson. It applies Gibbs free-energy minimization using an iterative, Lagrangian optimization scheme. Given elemental abundances, TEA calculates molecular abundances for a particular temperature and pressure or a list of temperature–pressure pairs. We tested the code against the method of Burrows and Sharp, the free thermochemical equilibrium code Chemical Equilibrium with Applications (CEA), and the example given by Burrows and Sharp. Using their thermodynamic data, TEA reproduces their final abundances, but with higher precision. We also applied the TEA abundance calculations to models of several hot-Jupiter exoplanets, producing expected results. TEA is written in Python in a modular format. There is a start guide, a user manual, and a code document in addition to this theory paper. TEA is available under a reproducible-research, open-source license via https://github.com/dzesmin/TEA.
3D equilibrium codes for mirror machines
International Nuclear Information System (INIS)
Kaiser, T.B.
1983-01-01
The codes developed for cumputing three-dimensional guiding center equilibria for quadrupole tandem mirrors are discussed. TEBASCO (Tandem equilibrium and ballooning stability code) is a code developed at LLNL that uses a further expansion of the paraxial equilibrium equation in powers of β (plasma pressure/magnetic pressure). It has been used to guide the design of the TMX-U and MFTF-B experiments at Livermore. Its principal weakness is its perturbative nature, which renders its validity for high-β calculation open to question. In order to compute high-β equilibria, the reduced MHD technique that has been proven useful for determining toroidal equilibria was adapted to the tandem mirror geometry. In this approach, the paraxial expansion of the MHD equations yields a set of coupled nonlinear equations of motion valid for arbitrary β, that are solved as an initial-value problem. Two particular formulations have been implemented in computer codes developed at NYU/Kyoto U and LLNL. They differ primarily in the type of grid, the location of the lateral boundary and the damping techniques employed, and in the method of calculating pressure-balance equilibrium. Discussions on these codes are presented in this paper. (Kato, T.)
Local approximation of a metapopulation's equilibrium.
Barbour, A D; McVinish, R; Pollett, P K
2018-04-18
We consider the approximation of the equilibrium of a metapopulation model, in which a finite number of patches are randomly distributed over a bounded subset [Formula: see text] of Euclidean space. The approximation is good when a large number of patches contribute to the colonization pressure on any given unoccupied patch, and when the quality of the patches varies little over the length scale determined by the colonization radius. If this is the case, the equilibrium probability of a patch at z being occupied is shown to be close to [Formula: see text], the equilibrium occupation probability in Levins's model, at any point [Formula: see text] not too close to the boundary, if the local colonization pressure and extinction rates appropriate to z are assumed. The approximation is justified by giving explicit upper and lower bounds for the occupation probabilities, expressed in terms of the model parameters. Since the patches are distributed randomly, the occupation probabilities are also random, and we complement our bounds with explicit bounds on the probability that they are satisfied at all patches simultaneously.
Equilibrium Partitioning Sediment Benchmarks (ESBs) for the ...
This document describes procedures to determine the concentrations of nonionic organic chemicals in sediment interstitial waters. In previous ESB documents, the general equilibrium partitioning (EqP) approach was chosen for the derivation of sediment benchmarks because it accounts for the varying bioavailability of chemicals in different sediments and allows for the incorporation of the appropriate biological effects concentration. This provides for the derivation of benchmarks that are causally linked to the specific chemical, applicable across sediments, and appropriately protective of benthic organisms. This equilibrium partitioning sediment benchmark (ESB) document was prepared by scientists from the Atlantic Ecology Division, Mid-Continent Ecology Division, and Western Ecology Division, the Office of Water, and private consultants. The document describes procedures to determine the interstitial water concentrations of nonionic organic chemicals in contaminated sediments. Based on these concentrations, guidance is provided on the derivation of toxic units to assess whether the sediments are likely to cause adverse effects to benthic organisms. The equilibrium partitioning (EqP) approach was chosen because it is based on the concentrations of chemical(s) that are known to be harmful and bioavailable in the environment. This document, and five others published over the last nine years, will be useful for the Program Offices, including Superfund, a
Nonflat equilibrium liquid shapes on flat surfaces.
Starov, Victor M
2004-01-15
The hydrostatic pressure in thin liquid layers differs from the pressure in the ambient air. This difference is caused by the actions of surface forces and capillary pressure. The manifestation of the surface force action is the disjoining pressure, which has a very special S-shaped form in the case of partial wetting (aqueous thin films and thin films of aqueous electrolyte and surfactant solutions, both free films and films on solid substrates). In thin flat liquid films the disjoining pressure acts alone and determines their thickness. However, if the film surface is curved then both the disjoining and the capillary pressures act simultaneously. In the case of partial wetting their simultaneous action results in the existence of nonflat equilibrium liquid shapes. It is shown that in the case of S-shaped disjoining pressure isotherm microdrops, microdepressions, and equilibrium periodic films exist on flat solid substrates. Criteria are found for both the existence and the stability of these nonflat equilibrium liquid shapes. It is shown that a transition from thick films to thinner films can go via intermediate nonflat states, microdepressions and periodic films, which both can be more stable than flat films within some range of hydrostatic pressure. Experimental investigations of shapes of the predicted nonflat layers can open new possibilities of determination of disjoining pressure in the range of thickness in which flat films are unstable.
Thermal equilibrium, stability and burn control
International Nuclear Information System (INIS)
Cohn, D.
1982-01-01
A number of aspects of the thermal stability and equilibrium control of ignited tokamak plasma have been investigated. Examined approaches were passive control (the effect of radial motion, the effect of radial motion and small additional transport loss), active control (the compression and decompression of plasma, subignited operation with small amount of variable external heating, and density control), and thermal equilibrium control (additional power loss from impurity radiation and enhanced transport from increased ripple). One-D calculation has been made on thermal instability eigen-modes. It was found that for electron thermal induction loss given by Alcator scaling and for neoclassical ion transport, there was at most one unstable mode with a temperature profile which maintains the temperature profile at thermal equilibrium. The effect of the coupling of temperature fluctuation and the fluctuation in major radius was investigated. Temperature driven radial motion combined with a small amount of ripple transport loss was found to be a very effective mechanism for passive thermal stability control. (Kato, T.)
Multi-period equilibrium/near-equilibrium in electricity markets based on locational marginal prices
Garcia Bertrand, Raquel
In this dissertation we propose an equilibrium procedure that coordinates the point of view of every market agent resulting in an equilibrium that simultaneously maximizes the independent objective of every market agent and satisfies network constraints. Therefore, the activities of the generating companies, consumers and an independent system operator are modeled: (1) The generating companies seek to maximize profits by specifying hourly step functions of productions and minimum selling prices, and bounds on productions. (2) The goals of the consumers are to maximize their economic utilities by specifying hourly step functions of demands and maximum buying prices, and bounds on demands. (3) The independent system operator then clears the market taking into account consistency conditions as well as capacity and line losses so as to achieve maximum social welfare. Then, we approach this equilibrium problem using complementarity theory in order to have the capability of imposing constraints on dual variables, i.e., on prices, such as minimum profit conditions for the generating units or maximum cost conditions for the consumers. In this way, given the form of the individual optimization problems, the Karush-Kuhn-Tucker conditions for the generating companies, the consumers and the independent system operator are both necessary and sufficient. The simultaneous solution to all these conditions constitutes a mixed linear complementarity problem. We include minimum profit constraints imposed by the units in the market equilibrium model. These constraints are added as additional constraints to the equivalent quadratic programming problem of the mixed linear complementarity problem previously described. For the sake of clarity, the proposed equilibrium or near-equilibrium is first developed for the particular case considering only one time period. Afterwards, we consider an equilibrium or near-equilibrium applied to a multi-period framework. This model embodies binary
Energy Technology Data Exchange (ETDEWEB)
Jaeger, J; Halbritter, G; Neumann-Hauf, G
1982-05-01
This report contains a review of literature on the subjects of the carbon cycle, the increase of the atmospheric CO/sub 2/ concentration and the possible impacts of an increased CO/sub 2/ concentration on the climate. In addition to this survey, the report discusses the questions that are still open and the resulting research needs. During the last twenty years a continual increase of the atmospheric carbon dioxide concentration by about 1-2 ppm per years has been observed. In 1958 the concentration was 315 ppm and this increased to 336 ppm in 1978. A rough estimate shows that the increase of the atmospheric carbon dioxide concentration is about half of the amount of carbon dioxide added to the atmosphere by the combustion of fossil fuels. Two possible sinks for the CO/sub 2/ released into the atmosphere are known: the ocean and the biota. The role of the biota is, however, unclear, since it can act both as a sink and as a source. Most models of the carbon cycle are one-dimensional and cannot be used for accurate predictions. Calculations with climate models have shown that an increased atmospheric CO/sub 2/ concentration leads to a warming of the earth's surface and lower atmosphere. Calculations show that a doubling of the atmospheric CO/sub 2/-concentration would lead to a net heating of the lower atmosphere and earth's surface by a global average of about 4 W m/sup -2/. Greater uncertainties arise in estimating the change in surface temperature resulting from this change in heating rate. It is estimated that the global average annual surface temperature would change between 1.5 and 4.5 K. There are, however, latitudinal and seasonal variations of the impact of increased CO/sub 2/ concentration. Other meteorological variables (e.g. precipitation, wind speed etc.) would also be changed. It appears that the impacts of the other products of fossil fuel combustion are unlikely to counteract the impacts of CO/sub 2/ on the climate.
... your menstrual cycle What happens during your menstrual cycle The menstrual cycle includes not just your period, but the rise ... that take place over the weeks in your cycle. Want to know what happens on each day ...
The thorium fuel cycle in water-moderated reactor systems
International Nuclear Information System (INIS)
Critoph, E.
1977-01-01
Current interest in the thorium cycle, as an alternative to the uranium cycle, for water-moderated reactors is based on two attractive aspects of its use - the extension of uranium resources, and the related lower sensitivity of energy costs to uranium price. While most of the scientific basis required is already available, some engineering demonstrations are needed to provide better economic data for rational decisions. Thorium and uranium cycles are compared with regard to reactor characteristics and technology, fuel-cycle technology, economic parameters, fuel-cycle costs, and system characteristics. There appear to be no major feasibility problems associated with the use of thorium, although development is required in the areas of fuel testing and fuel management. The use of thorium cycles implies recycling the fuel, and the major uncertainties are in the associated costs. Experience in the design and operation of fuel reprocessing and active-fabrication facilities is required to estimate costs to the accuracy needed for adequately defining the range of conditions economically favourable to thorium cycles. In heavy-water reactors (HWRs) thorium cycles having uranium requirements at equilibrium ranging from zero to a quarter of those for the natural-uranium once-through cycle appear feasible. An ''inventory'' of uranium of between 1 and 2Mg/MW(e) is required for the transition to equilibrium. The cycles with the lowest uranium requirements compete with the others only at high uranium prices. Using thorium in light-water reactors, uranium requirements can be reduced by a factor of between two and three from the once-through uranium cycle. The light-water breeder reactor, promising zero uranium requirements at equilibrium, is being developed. Larger uranium inventories are required than for the HWRs. The lead time, from a decision to use thorium to significant impact on uranium utilization (compared to uranium cycle, recycling plutonium), is some two decades
Tokamak equilibrium reconstruction code LIUQE and its real time implementation
International Nuclear Information System (INIS)
Moret, J.-M.; Duval, B.P.; Le, H.B.; Coda, S.; Felici, F.; Reimerdes, H.
2015-01-01
Highlights: • Algorithm vertical stabilisation using a linear parametrisation of the current density. • Experimentally derived model of the vacuum vessel to account for vessel currents. • Real-time contouring algorithm for flux surface averaged 1.5 D transport equations. • Full real time implementation coded in SIMULINK runs in less than 200 μs. • Applications: shape control, safety factor profile control, coupling with RAPTOR. - Abstract: Equilibrium reconstruction consists in identifying, from experimental measurements, a distribution of the plasma current density that satisfies the pressure balance constraint. The LIUQE code adopts a computationally efficient method to solve this problem, based on an iterative solution of the Poisson equation coupled with a linear parametrisation of the plasma current density. This algorithm is unstable against vertical gross motion of the plasma column for elongated shapes and its application to highly shaped plasmas on TCV requires a particular treatment of this instability. TCV's continuous vacuum vessel has a low resistance designed to enhance passive stabilisation of the vertical position. The eddy currents in the vacuum vessel have a sizeable influence on the equilibrium reconstruction and must be taken into account. A real time version of LIUQE has been implemented on TCV's distributed digital control system with a cycle time shorter than 200 μs for a full spatial grid of 28 by 65, using all 133 experimental measurements and including the flux surface average of quantities necessary for the real time solution of 1.5 D transport equations. This performance was achieved through a thoughtful choice of numerical methods and code optimisation techniques at every step of the algorithm, and was coded in MATLAB and SIMULINK for the off-line and real time version respectively
Identifying apparent local stable isotope equilibrium in a complex non-equilibrium system.
He, Yuyang; Cao, Xiaobin; Wang, Jianwei; Bao, Huiming
2018-02-28
Although being out of equilibrium, biomolecules in organisms have the potential to approach isotope equilibrium locally because enzymatic reactions are intrinsically reversible. A rigorous approach that can describe isotope distribution among biomolecules and their apparent deviation from equilibrium state is lacking, however. Applying the concept of distance matrix in graph theory, we propose that apparent local isotope equilibrium among a subset of biomolecules can be assessed using an apparent fractionation difference (|Δα|) matrix, in which the differences between the observed isotope composition (δ') and the calculated equilibrium fractionation factor (1000lnβ) can be more rigorously evaluated than by using a previous approach for multiple biomolecules. We tested our |Δα| matrix approach by re-analyzing published data of different amino acids (AAs) in potato and in green alga. Our re-analysis shows that biosynthesis pathways could be the reason for an apparently close-to-equilibrium relationship inside AA families in potato leaves. Different biosynthesis/degradation pathways in tubers may have led to the observed isotope distribution difference between potato leaves and tubers. The analysis of data from green algae does not support the conclusion that AAs are further from equilibrium in glucose-cultured green algae than in the autotrophic ones. Application of the |Δα| matrix can help us to locate potential reversible reactions or reaction networks in a complex system such as a metabolic system. The same approach can be broadly applied to all complex systems that have multiple components, e.g. geochemical or atmospheric systems of early Earth or other planets. Copyright © 2017 John Wiley & Sons, Ltd.
On the Concept "Chemical Equilibrium": The Associative Framework.
Gussarsky, Esther; Gorodetsky, Malka
1990-01-01
Word associations were used to map high school students' concepts of "chemical equilibrium" and "equilibrium." It was found that the preconception of the two concepts was differentiated on noncritical dimensions. (Author/CW)
On solutions to equilibrium problems for systems of stiffened gases
Flåtten, Tore; Morin, Alexandre; Munkejord, Svend Tollak
2011-01-01
We consider an isolated system of N immiscible fluids, each following a stiffened-gas equation of state. We consider the problem of calculating equilibrium states from the conserved fluid-mechanical properties, i.e., the partial densities and internal energies. We consider two cases; in each case mechanical equilibrium is assumed, but the fluids may or may not be in thermal equilibrium. For both cases, we address the issues of existence, uniqueness, and physical validity of equilibrium soluti...
Experimental determination of thermodynamic equilibrium in biocatalytic transamination
DEFF Research Database (Denmark)
Tufvesson, Pär; Jensen, Jacob Skibsted; Kroutil, Wolfgang
2012-01-01
The equilibrium constant is a critical parameter for making rational design choices in biocatalytic transamination for the synthesis of chiral amines. However, very few reports are available in the scientific literature determining the equilibrium constant (K) for the transamination of ketones....... Various methods for determining (or estimating) equilibrium have previously been suggested, both experimental as well as computational (based on group contribution methods). However, none of these were found suitable for determining the equilibrium constant for the transamination of ketones. Therefore...
Equilibrium Constant as Solution to the Open Chemical Systems
Zilbergleyt, B.
2008-01-01
According to contemporary views, equilibrium constant is relevant only to true thermodynamic equilibria in isolated systems with one chemical reaction. The paper presents a novel formula that ties-up equilibrium constant and chemical system composition at any state, isolated or open as well. Extending the logarithmic logistic map of the Discrete Thermodynamics of Chemical Equilibria, this formula maps the system population at isolated equilibrium into the population at any open equilibrium at...
The equilibrium response to doubling atmospheric CO2
International Nuclear Information System (INIS)
Mitchell, J.F.B.
1990-01-01
The equilibrium response of climate to increased atmospheric carbon dioxide as simulated by general circulation models is assessed. Changes that are physically plausible are summarized, along with an indication of the confidence attributable to those changes. The main areas of uncertainty are highlighted. They include: equilibrium experiments with mixed-layer oceans focusing on temperature, precipitation, and soil moisture; equilibrium studies with dynamical ocean-atmosphere models; results deduced from equilibrium CO 2 experiments; and priorities for future research to improve atmosphere models
Economic Analysis of Pyro-SFR Fuel Cycle
International Nuclear Information System (INIS)
Gao, Fanxing; Park, Byungheung; Kwon, Eunha; Ko, Wonil
2010-01-01
In this study, based on the material flow the economics of Pyro-SFR has been estimated. These are mainly two methodologies to perform nuclear fuel cycle cost study which is based on the material flow calculations. One is equilibrium model and the other is dynamic model. Equilibrium model focus on the batch study with the assumptions that the whole system is in a steady state and mass flow as well as the electricity production all through the fuel cycle is in equilibrium state, which calculates the electricity production within a certain period and associated material flow with reference to unit cost in order to obtain the cost of electricity. Dynamic model takes the time factor into consideration to simulate the actual cases. Compared with the dynamic analysis model, the outcome of equilibrium model is more theoretical comparisons, especially with regard to the large uncertainty of the development of the pyro-technology evaluated. In this study equilibrium model was built to calculate the material flow on a batch basis. With the unit cost being determined, the cost of each step of fuel cycle could be obtained, so does the FMC. Due to the unavoidable uncertainty with certain unit costs, evaluated cost range and uncertainty study are applied. Sensitivity analysis has also been performed to obtain the breakeven uranium price for Pyro-SFR against PWR-O T. Economics of Pyro-SFR fuel cycle scenario has been calculated and compared by employing equilibrium model. The LFCC were obtained, Pyro-SFR 7.68 mills/kWh. The Uranium price is the dominant driver of LFCC. Pyro-techniques also weight considerably in Pyro-SFR scenario. On consideration of the current unavoidable uncertainties introduced by certain cost data, cost range and triangle techniques were used to perform the uncertainty study which indicates that the gap between Pyro-SFR and PWR-O T fuel cycle scenario is relatively small
Toroidal equilibrium in an iron-core reversed field pinch
International Nuclear Information System (INIS)
Miller, G.
1984-04-01
An analytical theory of toroidal equilibrium in the ZT-40M reversed field pinch is obtained, including effects of iron cores and resistive shell. The iron cores alter the form of the equilibrium condition and cause the equilibrium to be unstable on the shell resistive time scale
An analysis of the concept of equilibrium in organization theory
Gazendam, H.W.M.; Simons, John L.
1998-01-01
This article analyzes how the equilibrium concept is used in four organization theories: the theories of Fayol, Mintzberg, Morgan, and Volberda. Equilibrium can be defined as balance, fit or requisite variety. Equilibrium is related to observables dependent on the definition of organization as work
Investigating High School Students' Understanding of Chemical Equilibrium Concepts
Karpudewan, Mageswary; Treagust, David F.; Mocerino, Mauro; Won, Mihye; Chandrasegaran, A. L.
2015-01-01
This study investigated the year 12 students' (N = 56) understanding of chemical equilibrium concepts after instruction using two conceptual tests, the "Chemical Equilibrium Conceptual Test 1" ("CECT-1") consisting of nine two-tier multiple-choice items and the "Chemical Equilibrium Conceptual Test 2"…
Equilibrium Price Dispersion in a Matching Model with Divisible Money
Kamiya, K.; Sato, T.
2002-01-01
The main purpose of this paper is to show that, for any given parameter values, an equilibrium with dispersed prices (two-price equilibrium) exists in a simple matching model with divisible money presented by Green and Zhou (1998).We also show that our two-price equilibrium is unique in certain
Hanging an Airplane: A Case Study in Static Equilibrium
Katz, Debora M.
2009-01-01
Our classrooms are filled with engineering majors who take a semester-long course in static equilibrium. Many students find this class too challenging and drop their engineering major. In our introductory physics class, we often breeze through static equilibrium; to physicists equilibrium is just a special case of Newton's second law. While it is…
Directory of Open Access Journals (Sweden)
Elzbieta Mlodawska
2014-12-01
Full Text Available Background/Aims: There are no data concerning renal function in population with valvular and non-valvular atrial fibrillation (AF. To assess renal function in patients with AF, the association between eGFR and AF perpetuation, in-hospital mortality. Methods: We studied 1523 patients with AF. Patients with chronic kidney disease (CKD were compared to population with preserved renal function. Results: CKD was more frequently observed in patients with valvular AF(p=0.009. In non-valvular AF patients eGFR 2 had more often permanent AF(p2DS2VASc score was 4.1±1.5 and HAS-BLED score was 2.1±1.2 and it was higher as compared to population with preserved renal function (p75 years old(OR=3.70,p=0.01,95%CI1.33-10.28, with CKD (OR=2.61,p=0.03,95%CI1.09-6.23. The type of AF had no significant influence on in-hospital mortality(OR=0.71,p=0.45,95%CI0.30-1.70. Conclusions: CKD is more often observed in patients with valvular AF. In population with non-valvular AF decreased eGFR is associated with permanent type of AF and with higher CHA2DS2VASc and HAS-BLED score. Among valvular AF patients there are no differences in type of AF between patients with and without CKD. There is the correlation between CKD and AF perpetuation but only in non-valvular population.
Definition of breeding gain for the closed fuel cycle and application to a gas cooled fast reactor
International Nuclear Information System (INIS)
Van Rooijen, W. F. G.; Kloosterman, J. L.; Van Der Hagen, T. H. J. J.; Van Dam, H.
2006-01-01
In this paper a definition is given for the Breeding Gain (BG) of a nuclear reactor, taking into account compositional changes of the fuel during irradiation, cool down and reprocessing. A definition is given for the reactivity weights required to calculate BG. To calculate the effects of changes in the initial fuel composition on BG, first order nuclide perturbation theory is used. The theory is applied to the fuel cycle of GFR600, a 600 MWth Generation IV Gas Cooled Fast Reactor. This reactor should have a closed fuel cycle, with a BG equal to zero, breeding just enough new fuel during irradiation to allow refueling by only adding fertile material. All Heavy Metal is recycled in the closed fuel cycle. The result is that a closed fuel cycle is possible if the reprocessing has low losses ( 238 U, 15% Pu, and low amounts of the Minor Actinides. (authors)
International Nuclear Information System (INIS)
Song, S.-H.; Shen, D.-D.; Yuan, Z.-X.; Liu, J.; Xu, T.-D.; Weng, L.-Q.
2003-01-01
Grain boundary segregation of phosphorus in a P-doped 2.25Cr1Mo steel during ageing at 540 deg. C after quenching from 980 deg. C is examined by Auger electron spectroscopy. The segregation is a combined effect of equilibrium segregation and non-equilibrium segregation. The effect of phosphorus non-equilibrium segregation is to enhance the kinetics of its equilibrium segregation
International Nuclear Information System (INIS)
Jiang, Shixiao W; Lu, Haihao; Zhou, Douglas; Cai, David
2016-01-01
Characterizing dispersive wave turbulence in the long time dynamics is central to understanding of many natural phenomena, e.g., in atmosphere ocean dynamics, nonlinear optics, and plasma physics. Using the β -Fermi–Pasta–Ulam nonlinear system as a prototypical example, we show that in thermal equilibrium and non-equilibrium steady state the turbulent state even in the strongly nonlinear regime possesses an effective linear stochastic structure in renormalized normal variables. In this framework, we can well characterize the spatiotemporal dynamics, which are dominated by long-wavelength renormalized waves. We further demonstrate that the energy flux is nearly saturated by the long-wavelength renormalized waves in non-equilibrium steady state. The scenario of such effective linear stochastic dynamics can be extended to study turbulent states in other nonlinear wave systems. (paper)
Equilibrium and shot noise in mesoscopic systems
Energy Technology Data Exchange (ETDEWEB)
Martin, T.
1994-10-01
Within the last decade, there has been a resurgence of interest in the study of noise in Mesoscopic devices, both experimentally and theoretically. Noise in solid state devices can have different origins: there is 1/f noise, which is believed to arise from fluctuations in the resistance of the sample due to the motion of impurities. On top of this contribution is a frequency independent component associated with the stochastic nature of electron transport, which will be the focus of this paper. If the sample considered is small enough that dephasing and inelastic effects can be neglected, equilibrium (thermal) and excess noise can be completely described in terms of the elastic scattering properties of the sample. As mentioned above, noise arises as a consequence of random processes governing the transport of electrons. Here, there are two sources of randomness: first, electrons incident on the sample occupy a given energy state with a probability given by the Fermi-Dirac distribution function. Secondly, electrons can be transmitted across the sample or reflected in the same reservoir where they came from with a probability given by the quantum mechanical transmission/reflection coefficients. Equilibrium noise refers to the case where no bias voltage is applied between the leads connected to the sample, where thermal agitation alone allows the electrons close to the Fermi level to tunnel through the sample. In general, equilibrium noise is related to the conductance of the sample via the Johnson-Nyquist formula. In the presence of a bias, in the classical regime, one expects to recover the full shot noise < {Delta}{sup 2}I >= 2I{Delta}{mu} as was observed a long time ago in vacuum diodes. In the Mesoscopic regime, however, excess noise is reduced below the shot noise level. The author introduces a more intuitive picture, where the current passing through the device is a superposition of pulses, or electron wave packets, which can be transmitted or reflected.