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02392 Study of the design variables for a wet-chamber gas meter prototype (MGCH)
14 Fuel science and technology (fundamental science, analysis, instrumentation) 06•02384 Labour productivity, energy intensity and economic performance in small enterprises: a study of brick enterprises cluster in India Bala Subrahmanya, M. H. Energy Conversion and Management, 2006, 47, (6), 763 777. This paper probes the role of labour efficiency in promoting energy efficiency and economic performance with reference to small-scale brick enterprises' cluster in Malur, Karnataka State, India. In the bricks industry, the technology in use being similar, labour efficiency has a negative influence on energy cost. Therefore, those enterprises that exhibited higher labour productivities had lower average energy intensity and higher returns to scale as compared to those that had lower labour productivities. Considering this, improvement of labour efficiency can be an alternative approach for energy efficiency improvement in energy intensive small-scale industries in developing countries like India, which face the obstacle of financial constraints in up-grading technology as a means of energy efficiency improvement.
06/02385 Landfill siting using GIS, fuzzy logic and the Delphi method Hatzichristos, T. and Giaoutzi, M. International Journal of Environmental Technology and Management. 2006, 6, (1 2), 218 231. The focus of this paper is on the development of an evaluation methodology for landfill siting. The first part of the paper presents the methodology developed, utilizing GIS technology for the analysis and visualization of the geographic data, and fuzzy logic for the evaluation of the final results. The Delphi method is also utilized to determine the membership functions used in the fuzzy logic approach. In the second part, a case study is presented, concerning one of the 27 prefectures of Egypt. Finally the advantages and disadvantages of the methodology are discussed.
06102386 Measurements of activation cross-sections for the 19F(n, o016N reaction for neutrons with energies between 13 and 15 MeV Durusoy, A. and Reyhancan, I. A. Annals of Nuclear Energy, 2006, 33, (2), 159-162. In this study, activation cross-sections were measured for the X9F(n, 16 . . . . a) N reaction at six different neutron energies from 13.5 and 14.9 MeV. The fast neutrons were produced via the 3H(d,n)4He reaction on SAMES T-400 neutron generator. The cyclic activation technique was used. Induced gamma activities were measured by a high-resolution gamma-ray spectrometer with high-purity germanium (HpGe) detector. Measurements were corrected for gamma-ray attenuations, random coincidence (pile-up), dead time and fluctuation of neutron flux. Results were compared with the previous works.
06•02387 Motion planning for PLM: state of the art and perspectives Laumond, J.-P. International Journal of Product Lifecyele Management, 2006, 1, (2), 129 142. This paper presents an overview of algorithmic motion planning techniques together with their current and potential applications to product lifecycle management (PLM). After introducing the main concepts that appeared in the late 1970s in robotics, the paper focuses on probabilistic techniques of the 1990s, which constitute a technological breakthrough, with respect to the deterministic approaches developed in the 1980s. From this the progress of applications in manufacturing (robot programming), CAD/CAM Design (mechanical part assembly), as well as in process engineering (maintenance in industrial facilities), can be seen.
06/02388 Neutron kinetics in subcritical cores with application to the source modulation method Wright, J. and P~izsit, 1. Annals of Nuclear Energy, 2006, 33, (2), 149158. This paper investigates the performance of the so-called source modulation technique for the measurement of reactivity in subcritical, source-driven cores. Methods of measuring reactivity by a single detector, including the source modulation method, are based on the assumption of point kinetic behaviour of the core. Deviations from point kinetic behaviour will lead to an inaccurate estimation of the reactivity. Hence, first, the conditions of point kinetic behaviour in subcritical source-driven cores are revisited. In addition to the known conditions for such behaviour, which have an analogy to those in critical cores, some additional cases are found which only exist in subcritical cores. Then the performance of the source modulation technique is investigated. It is found that the error of the method, originally thought to be due exclusively to the deviation of the local detector signal from the amplitude factor of point kinetics, remains finite and non-zero even in the limit of exact point kinetic behaviour (e.g. with low frequencies or deep subcriticalities). This is demonstrated and explained by analytical formulae. Some remedies for this shortcoming of the method are also suggested and discussed.
362
Fuel and Energy Abstracts September 2006
06•02389 Numerical computation of time lags and decrement factors for different building materials Asan, H. Building and Environment, 2006, 41, (5), 615 620. In this study, time lags and decrement factors for different building materials have been investigated numerically. For this purpose, one dimensional transient heat conduction equation was solved using the Crank-Nicolson scheme under convection boundary conditions. To the outer surface of the wall, periodic boundary conditions were applied. Twenty-six different building materials were selected for analysis. The computations were repeated for eight different thickness of each material and the effects of thickness and the type of material on time lag and decrement factor were investigated. It was found that thickness of material and the type of the material have a very profound effect on the time lag and decrement factor. The results of present study are useful for designing more effective passive solar buildings and other related areas.
06/02390 On the accuracy of reactor physics calculations for square HPLWR fuel assemblies Jatuff, F. et al. Annals of Nuclear Energy, 2006, 33, (2), 198 207. Although the supercritical-pressure or high-performance light water reactor (HPLWR) concept is largely based on the well-established technological experience available with conventional light water reactors, there is still no consensus on various key design features such as an optimal layout for the fuel assembly. This results mainly from the very large density variations of supercritical-pressure water in the core, which render it difficult to ensure reliable values for parameters such as power peaking factors and reactivity worths. The present paper describes studies carried out to compare deterministic and Monte Carlo codes for analysing a representative square HPLWR lattice with uniform 5%-enriched UO2 fuel. The main purpose has been to assess the prediction accuracies achievable for integral parameters such as the multiplication factor, control absorber effectiveness, moderator/coolant density reactivity feedback and pin power distributions. The results show good agreement between the deterministic and stochastic calculations for the unperturbed lattice. However, for certain perturbed situations involving, for example, local coolant density changes in the assembly or control absorber insertion, the observed discrepancies are large enough to question the basic viability of the reactor physics design, e.g. with respect to the thermal performance.
06/02391 Permeability model optimization of a highly heterogeneous reservoir using streamline-based dynamic data inversion Vargas, J.-A. and Idrobo, E. A. Ciencia Tecnologla y Futuro, 2003, 2, (4), 75 94. The main objective of oilfield characterization is to establish the oilfleld's model through the integration of all usable information. The traditional scope includes the modelling based primarily on static information, having as a final stage of the process, the validation of the model with the dynamic information available. The term validation involves a procedure that only tries to guarantee that the productive zones being modelled feature adequate oilfields properties. The new trends in oilfield characterization show that the dynamic information available should be integrated to the oilfield's model. This process is not trivial, since it includes an optimization process framed by a continuous process of light simulation. In this paper, a semi-analytical solution is proposed, as a product of the combination of geostatistical techniques with streamline simulation algorithms and of dynamic inversion of data for the optimization of the permeability model for heterogeneous oilfields, while verifying the effectiveness of the dynamic inversion scheme in two phases: adjustments to irruption times, followed by adjustments to the amplitude of the water cuts. The methodology proposed was successfully applied to synthetic models and to a field case. The synthetic models were used to validate the efficiency of the procedure on classical methods of oilfield characterization. The field case corresponds to a highly heterogeneous oilfield: the A2 sands of block VII of the Casabe field. This example includes 22 productive wells and 19 injecting wells in an oilfleld of fluvial origin, made up of stratigraphically complex geometries, such as crossstratification, preferential flow channels, and lateral changes to facies and thicknesses, among others. The most important conclusion from this paper is that the regular injection patterns, of five pre-established points, are not efficient enough to optimize the secondary recover process; therefore, the suggestion is made to establish irregular models based on the trajectory of the flow lines.
06/02392 Study of the design variables for a wet-chamber gas meter prototype (MGCH) Patifio, C.-H. et al. Ciencia Tecnologia y Futuro, 2004, 2, (5), 131 144. This paper established the most important variables and their correlation that affect design and operation of wet-chamber gas meters (MGCH), focused on the gas pressure difference along the meter and the sealing-liquid level. In order to study variable behaviour, a
14 Fuel science and technology (fuel cell technology) simulation was carried out based on computational systems. The mathematical model developed was built taking into account common features in present wet test gas meter as their internal configuration. Therefore, this work can be understood as a general analysis and its conclusions can be extended to whichever meter of this type. A software package was developed to facilitate the analysis of the variables involved in this physical process; besides the drum sizing was modelling using a CAD software. As a result of this investigation, theoretical basis were established for the analysing and designing of a M G C H meter, as a previous phase to the construction and evaluation of the prototype. Uncertainty analysis of each variable implicates in this model was beyond the scope of this study.
problems at higher stress ranges beyond shakedown involving changing residual stress fields. These include the evaluation of the plastic strain amplitude, ratchet limit and accumulated creep strains during high temperature dwell periods. The results are compared with calculation methods typical of the R5 methodologies. As in the accompanying paper, a 3D holed plate subjected to cyclic thermal load and constant mechanical load is assessed in detail as a typical example. The results demonstrate the flexibility of the linear matching method compared with current typical applications of high temperature assessment procedures.
06•02393 Study on prevention of ice adhesion to cooling wall due to voltage impression in ice storage - discussion on possibility of attraction of oil to wall
Zfieng, D. et al. Applied Energy~ 2006, 83, (4), 311-323. An absorption power/cooling combined cycle is proposed, and a thermodynamic analysis of the cycle is performed using log p T, log p h and T s diagrams. Based upon two performance criteria, the overall thermal-efficiency and exergy efficiency, the cycle has been analysed by means of a simulation. The overall thermal efficiency of the cycle is 24.2%, and the exergy efficiency is 37.3%.
Matsumoto, K. and Sakurai, H. International Journal of Refrigeration, 2006, 29, (1), 142-149. For ice storage, one of authors has studied new ice slurry formed by cooling a water-oil mixture with stirring. When the mixture is stirred in a vessel, oil is charged by static electricity due to friction. If the vessel wall can attract charged oil, prevention of ice adhesion to the wall may be realized. Therefore, in this paper, in order to observe behaviour of charged water-oil droplet or mixture in electric field by a high speed camera or video camera, two types of experiments were carried out. One was that the water-oil droplet charged by static electricity was made to fall plumb down between two electrodes with electric field or without electric field, varying the water content of droplet. The other was that a constant voltage was applied on the vessel filled with the water-oil mixture stirred. From experiments, it was confirmed that attracting force between the charged wall (electrode) and charged oil acted.
06•02394 The exergy fields in transport processes: their calculation and use Lior, N. et al. Energy, 2006, 31, (5), 553-578. This paper is a brief review of the method for analysing the space and time dependent exergy and irreversibility fields in processes. It presents the basic equations, the method for their use, major literature sources, and three examples from the authors' work: flow desiccation, combustion of oil droplets, and combustion of pulverized coal. Conclusions from this Second Law analysis are used to attempt process improvement suggestions.
06/02395 The linear matching method applied to the high temperature life integrity of structures. Part 1. Assessments involving constant residual stress fields Chert, H. F. et al. International Journal of Pressure Vessels and Piping, 2006, 83, (23, 123-135. Design and life assessment procedures for high temperatures are based on 'expert knowledge' in structural mechanics and materials science, combined with simplified methods of structural analysis. Of these, R5 is one of the most widely used life assessment methods internationally with procedures based on reference stress techniques and shakedown calculations using linear elastic solutions. These have been augmented by full finite element analysis and, recently, the development of a new programming method, the linear matching method (LMM), that allows a range of direct solutions that include shakedown methods and simplified analysis in excess of shakedown. In this paper, LMM procedures are compared with calculations typical of those employed in R5 for cyclic loading problems when the assumption of a constant residual stress field is appropriate including shakedown and limit analyses, creep rupture analysis and the evaluation of accumulated creep deformation. A typical example of a 3D holed plate subjected to a cyclic thermal load and a constant mechanical load is assessed in detail. These comparisons demonstrate the significant advantages of linear matching methods for a typical case. For a range of cyclic problems when the residual stress field varies during the cycle, which include the evaluation of plastic strain amplitude, ratchet limit and accumulated creep strains during a high temperature dwell periods, the corresponding LMM and R5 procedures are discussed in an accompanying paper.
06/02396 The linear matching method applied to the high temperature life integrity of structures. Part 2, Assessments beyond shakedown involving changing residual stress fields Chen, H. F. et al. Ittternational Journal of Pressure Vessels attd Piping, 2006, 83, (2), 136 147. In an accompanying paper, the application of the linear matching method to the high temperature life assessment of structures was discussed and compared with assessment procedures, typical of those used in RS, for a range of cyclic problems within shakedown. These included shakedown and limit analyses, creep rupture analysis and the evaluation of rapid cycle creep deformation. In this paper, procedures based on the linear matching method are presented for a range of cyclic
06/02397 Thermodynamic analysis of a novel absorption power/cooling combined-cycle
06/02398 Thermodynamic analysis of absorption systems using artificial neural network Sencan, A. et al. Renewable Energy, 2006, 31, (1), 29-43. Thermodynamic analysis of absorption systems is a very complex process, mainly because of the limited experimental data and analytical functions required for calculating the thermodynamic properties of fluid pairs, which usually involves the solution of complex differential equations, In order to simplify this complex process, Artificial neural networks (ANNs) are used. In this study, ANNs are used as a new approach for the determination of the thermodynamic properties of LiBr-water and LiCl-water solutions which have been the most widely used in the absorption heat pump systems. Instead of complex differential equations and limited experimental data, faster and simpler solutions were obtained by using equations derived from the ANN model. It was found that the coefficient of multiple determination (R 2value) between the actual and A N N predicted data is equal to about 0.999 for the enthalpy of both LiBr-water and LiC1 water solutions. As seen from the results obtained, the calculated thermodynamic properties are obviously within acceptable limits. In addition, the coefficient of performance (COP) of absorption systems operating under different conditions with LiB~water and LiCl-water solutions is calculated. The use of the derived equations, which can be employed with any programming language or spreadsheet program for the estimation of the enthalpy of the solutions, as described in this paper, may make the use of dedicated A N N software unnecessary.
Fuel cell technology 06/02399 A hybrid model of cathode of PEM fuel cell using the interdigitated gas distributor Liu, X.-L. et al. International Journol of IIydrogen Energy, 2006, 31, (33, 379 389. A two-dimensional (2D), single- and two-phase, hybrid multi-component transport model is developed for the cathode of PEM fuel cell using interdigitated gas distributor. The continuity equation and Darcy's law are used to describe the flow of the reactant gas and production water. The production water is treated as vapour when the current density is small, and as two-phase while the current density is greater than the critical current density. The advection-diffusion equations are utilized to study species transport of multi-component mixture gas. The Butler-Volmer equation is prescribed for the domain in the catalyst layer. The predicted results of the hybrid model agree well with the available experimental data. The model is used to investigate the effects of operating conditions and the cathode structure parameters on the performance of the PEM fuel cell. It is observed that liquid water appears originally in the cathodic catalyst layer over outlet channel under intermediate current and tends to be distributed uniformly by the capillary force with the increase of the current. It is found that reduction of the width of outlet channel can enhance the performance of PEM fuel cell via the increase of the current density over this region, which has, seemingly, not been discussed in previous literatures.
06/02400 Characterization of electrode structures and the related performance of direct methanol fuel cells Chert, C. Y. and Tsao, C. S. International Journal of Hydrogen Energy, 2006, 31, (3), 391-398. The performance of membrane electrode assemblies (MEAs) in fuel cells is substantially affected by the structures of the electrodes. An increase of about 25% in power performance was achieved merely by
Fuel and Energy Abstracts September 2006
363
06/02385 Landfill siting using GIS, fuzzy logic and the Delphi method Hatzichristos, T. and Giaoutzi, M. International Journal of Environmental Technology and Management. 2006, 6, (1 2), 218 231. The focus of this paper is on the development of an evaluation methodology for landfill siting. The first part of the paper presents the methodology developed, utilizing GIS technology for the analysis and visualization of the geographic data, and fuzzy logic for the evaluation of the final results. The Delphi method is also utilized to determine the membership functions used in the fuzzy logic approach. In the second part, a case study is presented, concerning one of the 27 prefectures of Egypt. Finally the advantages and disadvantages of the methodology are discussed.
06102386 Measurements of activation cross-sections for the 19F(n, o016N reaction for neutrons with energies between 13 and 15 MeV Durusoy, A. and Reyhancan, I. A. Annals of Nuclear Energy, 2006, 33, (2), 159-162. In this study, activation cross-sections were measured for the X9F(n, 16 . . . . a) N reaction at six different neutron energies from 13.5 and 14.9 MeV. The fast neutrons were produced via the 3H(d,n)4He reaction on SAMES T-400 neutron generator. The cyclic activation technique was used. Induced gamma activities were measured by a high-resolution gamma-ray spectrometer with high-purity germanium (HpGe) detector. Measurements were corrected for gamma-ray attenuations, random coincidence (pile-up), dead time and fluctuation of neutron flux. Results were compared with the previous works.
06•02387 Motion planning for PLM: state of the art and perspectives Laumond, J.-P. International Journal of Product Lifecyele Management, 2006, 1, (2), 129 142. This paper presents an overview of algorithmic motion planning techniques together with their current and potential applications to product lifecycle management (PLM). After introducing the main concepts that appeared in the late 1970s in robotics, the paper focuses on probabilistic techniques of the 1990s, which constitute a technological breakthrough, with respect to the deterministic approaches developed in the 1980s. From this the progress of applications in manufacturing (robot programming), CAD/CAM Design (mechanical part assembly), as well as in process engineering (maintenance in industrial facilities), can be seen.
06/02388 Neutron kinetics in subcritical cores with application to the source modulation method Wright, J. and P~izsit, 1. Annals of Nuclear Energy, 2006, 33, (2), 149158. This paper investigates the performance of the so-called source modulation technique for the measurement of reactivity in subcritical, source-driven cores. Methods of measuring reactivity by a single detector, including the source modulation method, are based on the assumption of point kinetic behaviour of the core. Deviations from point kinetic behaviour will lead to an inaccurate estimation of the reactivity. Hence, first, the conditions of point kinetic behaviour in subcritical source-driven cores are revisited. In addition to the known conditions for such behaviour, which have an analogy to those in critical cores, some additional cases are found which only exist in subcritical cores. Then the performance of the source modulation technique is investigated. It is found that the error of the method, originally thought to be due exclusively to the deviation of the local detector signal from the amplitude factor of point kinetics, remains finite and non-zero even in the limit of exact point kinetic behaviour (e.g. with low frequencies or deep subcriticalities). This is demonstrated and explained by analytical formulae. Some remedies for this shortcoming of the method are also suggested and discussed.
362
Fuel and Energy Abstracts September 2006
06•02389 Numerical computation of time lags and decrement factors for different building materials Asan, H. Building and Environment, 2006, 41, (5), 615 620. In this study, time lags and decrement factors for different building materials have been investigated numerically. For this purpose, one dimensional transient heat conduction equation was solved using the Crank-Nicolson scheme under convection boundary conditions. To the outer surface of the wall, periodic boundary conditions were applied. Twenty-six different building materials were selected for analysis. The computations were repeated for eight different thickness of each material and the effects of thickness and the type of material on time lag and decrement factor were investigated. It was found that thickness of material and the type of the material have a very profound effect on the time lag and decrement factor. The results of present study are useful for designing more effective passive solar buildings and other related areas.
06/02390 On the accuracy of reactor physics calculations for square HPLWR fuel assemblies Jatuff, F. et al. Annals of Nuclear Energy, 2006, 33, (2), 198 207. Although the supercritical-pressure or high-performance light water reactor (HPLWR) concept is largely based on the well-established technological experience available with conventional light water reactors, there is still no consensus on various key design features such as an optimal layout for the fuel assembly. This results mainly from the very large density variations of supercritical-pressure water in the core, which render it difficult to ensure reliable values for parameters such as power peaking factors and reactivity worths. The present paper describes studies carried out to compare deterministic and Monte Carlo codes for analysing a representative square HPLWR lattice with uniform 5%-enriched UO2 fuel. The main purpose has been to assess the prediction accuracies achievable for integral parameters such as the multiplication factor, control absorber effectiveness, moderator/coolant density reactivity feedback and pin power distributions. The results show good agreement between the deterministic and stochastic calculations for the unperturbed lattice. However, for certain perturbed situations involving, for example, local coolant density changes in the assembly or control absorber insertion, the observed discrepancies are large enough to question the basic viability of the reactor physics design, e.g. with respect to the thermal performance.
06/02391 Permeability model optimization of a highly heterogeneous reservoir using streamline-based dynamic data inversion Vargas, J.-A. and Idrobo, E. A. Ciencia Tecnologla y Futuro, 2003, 2, (4), 75 94. The main objective of oilfield characterization is to establish the oilfleld's model through the integration of all usable information. The traditional scope includes the modelling based primarily on static information, having as a final stage of the process, the validation of the model with the dynamic information available. The term validation involves a procedure that only tries to guarantee that the productive zones being modelled feature adequate oilfields properties. The new trends in oilfield characterization show that the dynamic information available should be integrated to the oilfield's model. This process is not trivial, since it includes an optimization process framed by a continuous process of light simulation. In this paper, a semi-analytical solution is proposed, as a product of the combination of geostatistical techniques with streamline simulation algorithms and of dynamic inversion of data for the optimization of the permeability model for heterogeneous oilfields, while verifying the effectiveness of the dynamic inversion scheme in two phases: adjustments to irruption times, followed by adjustments to the amplitude of the water cuts. The methodology proposed was successfully applied to synthetic models and to a field case. The synthetic models were used to validate the efficiency of the procedure on classical methods of oilfield characterization. The field case corresponds to a highly heterogeneous oilfield: the A2 sands of block VII of the Casabe field. This example includes 22 productive wells and 19 injecting wells in an oilfleld of fluvial origin, made up of stratigraphically complex geometries, such as crossstratification, preferential flow channels, and lateral changes to facies and thicknesses, among others. The most important conclusion from this paper is that the regular injection patterns, of five pre-established points, are not efficient enough to optimize the secondary recover process; therefore, the suggestion is made to establish irregular models based on the trajectory of the flow lines.
06/02392 Study of the design variables for a wet-chamber gas meter prototype (MGCH) Patifio, C.-H. et al. Ciencia Tecnologia y Futuro, 2004, 2, (5), 131 144. This paper established the most important variables and their correlation that affect design and operation of wet-chamber gas meters (MGCH), focused on the gas pressure difference along the meter and the sealing-liquid level. In order to study variable behaviour, a
14 Fuel science and technology (fuel cell technology) simulation was carried out based on computational systems. The mathematical model developed was built taking into account common features in present wet test gas meter as their internal configuration. Therefore, this work can be understood as a general analysis and its conclusions can be extended to whichever meter of this type. A software package was developed to facilitate the analysis of the variables involved in this physical process; besides the drum sizing was modelling using a CAD software. As a result of this investigation, theoretical basis were established for the analysing and designing of a M G C H meter, as a previous phase to the construction and evaluation of the prototype. Uncertainty analysis of each variable implicates in this model was beyond the scope of this study.
problems at higher stress ranges beyond shakedown involving changing residual stress fields. These include the evaluation of the plastic strain amplitude, ratchet limit and accumulated creep strains during high temperature dwell periods. The results are compared with calculation methods typical of the R5 methodologies. As in the accompanying paper, a 3D holed plate subjected to cyclic thermal load and constant mechanical load is assessed in detail as a typical example. The results demonstrate the flexibility of the linear matching method compared with current typical applications of high temperature assessment procedures.
06•02393 Study on prevention of ice adhesion to cooling wall due to voltage impression in ice storage - discussion on possibility of attraction of oil to wall
Zfieng, D. et al. Applied Energy~ 2006, 83, (4), 311-323. An absorption power/cooling combined cycle is proposed, and a thermodynamic analysis of the cycle is performed using log p T, log p h and T s diagrams. Based upon two performance criteria, the overall thermal-efficiency and exergy efficiency, the cycle has been analysed by means of a simulation. The overall thermal efficiency of the cycle is 24.2%, and the exergy efficiency is 37.3%.
Matsumoto, K. and Sakurai, H. International Journal of Refrigeration, 2006, 29, (1), 142-149. For ice storage, one of authors has studied new ice slurry formed by cooling a water-oil mixture with stirring. When the mixture is stirred in a vessel, oil is charged by static electricity due to friction. If the vessel wall can attract charged oil, prevention of ice adhesion to the wall may be realized. Therefore, in this paper, in order to observe behaviour of charged water-oil droplet or mixture in electric field by a high speed camera or video camera, two types of experiments were carried out. One was that the water-oil droplet charged by static electricity was made to fall plumb down between two electrodes with electric field or without electric field, varying the water content of droplet. The other was that a constant voltage was applied on the vessel filled with the water-oil mixture stirred. From experiments, it was confirmed that attracting force between the charged wall (electrode) and charged oil acted.
06•02394 The exergy fields in transport processes: their calculation and use Lior, N. et al. Energy, 2006, 31, (5), 553-578. This paper is a brief review of the method for analysing the space and time dependent exergy and irreversibility fields in processes. It presents the basic equations, the method for their use, major literature sources, and three examples from the authors' work: flow desiccation, combustion of oil droplets, and combustion of pulverized coal. Conclusions from this Second Law analysis are used to attempt process improvement suggestions.
06/02395 The linear matching method applied to the high temperature life integrity of structures. Part 1. Assessments involving constant residual stress fields Chert, H. F. et al. International Journal of Pressure Vessels and Piping, 2006, 83, (23, 123-135. Design and life assessment procedures for high temperatures are based on 'expert knowledge' in structural mechanics and materials science, combined with simplified methods of structural analysis. Of these, R5 is one of the most widely used life assessment methods internationally with procedures based on reference stress techniques and shakedown calculations using linear elastic solutions. These have been augmented by full finite element analysis and, recently, the development of a new programming method, the linear matching method (LMM), that allows a range of direct solutions that include shakedown methods and simplified analysis in excess of shakedown. In this paper, LMM procedures are compared with calculations typical of those employed in R5 for cyclic loading problems when the assumption of a constant residual stress field is appropriate including shakedown and limit analyses, creep rupture analysis and the evaluation of accumulated creep deformation. A typical example of a 3D holed plate subjected to a cyclic thermal load and a constant mechanical load is assessed in detail. These comparisons demonstrate the significant advantages of linear matching methods for a typical case. For a range of cyclic problems when the residual stress field varies during the cycle, which include the evaluation of plastic strain amplitude, ratchet limit and accumulated creep strains during a high temperature dwell periods, the corresponding LMM and R5 procedures are discussed in an accompanying paper.
06/02396 The linear matching method applied to the high temperature life integrity of structures. Part 2, Assessments beyond shakedown involving changing residual stress fields Chen, H. F. et al. Ittternational Journal of Pressure Vessels attd Piping, 2006, 83, (2), 136 147. In an accompanying paper, the application of the linear matching method to the high temperature life assessment of structures was discussed and compared with assessment procedures, typical of those used in RS, for a range of cyclic problems within shakedown. These included shakedown and limit analyses, creep rupture analysis and the evaluation of rapid cycle creep deformation. In this paper, procedures based on the linear matching method are presented for a range of cyclic
06/02397 Thermodynamic analysis of a novel absorption power/cooling combined-cycle
06/02398 Thermodynamic analysis of absorption systems using artificial neural network Sencan, A. et al. Renewable Energy, 2006, 31, (1), 29-43. Thermodynamic analysis of absorption systems is a very complex process, mainly because of the limited experimental data and analytical functions required for calculating the thermodynamic properties of fluid pairs, which usually involves the solution of complex differential equations, In order to simplify this complex process, Artificial neural networks (ANNs) are used. In this study, ANNs are used as a new approach for the determination of the thermodynamic properties of LiBr-water and LiCl-water solutions which have been the most widely used in the absorption heat pump systems. Instead of complex differential equations and limited experimental data, faster and simpler solutions were obtained by using equations derived from the ANN model. It was found that the coefficient of multiple determination (R 2value) between the actual and A N N predicted data is equal to about 0.999 for the enthalpy of both LiBr-water and LiC1 water solutions. As seen from the results obtained, the calculated thermodynamic properties are obviously within acceptable limits. In addition, the coefficient of performance (COP) of absorption systems operating under different conditions with LiB~water and LiCl-water solutions is calculated. The use of the derived equations, which can be employed with any programming language or spreadsheet program for the estimation of the enthalpy of the solutions, as described in this paper, may make the use of dedicated A N N software unnecessary.
Fuel cell technology 06/02399 A hybrid model of cathode of PEM fuel cell using the interdigitated gas distributor Liu, X.-L. et al. International Journol of IIydrogen Energy, 2006, 31, (33, 379 389. A two-dimensional (2D), single- and two-phase, hybrid multi-component transport model is developed for the cathode of PEM fuel cell using interdigitated gas distributor. The continuity equation and Darcy's law are used to describe the flow of the reactant gas and production water. The production water is treated as vapour when the current density is small, and as two-phase while the current density is greater than the critical current density. The advection-diffusion equations are utilized to study species transport of multi-component mixture gas. The Butler-Volmer equation is prescribed for the domain in the catalyst layer. The predicted results of the hybrid model agree well with the available experimental data. The model is used to investigate the effects of operating conditions and the cathode structure parameters on the performance of the PEM fuel cell. It is observed that liquid water appears originally in the cathodic catalyst layer over outlet channel under intermediate current and tends to be distributed uniformly by the capillary force with the increase of the current. It is found that reduction of the width of outlet channel can enhance the performance of PEM fuel cell via the increase of the current density over this region, which has, seemingly, not been discussed in previous literatures.
06/02400 Characterization of electrode structures and the related performance of direct methanol fuel cells Chert, C. Y. and Tsao, C. S. International Journal of Hydrogen Energy, 2006, 31, (3), 391-398. The performance of membrane electrode assemblies (MEAs) in fuel cells is substantially affected by the structures of the electrodes. An increase of about 25% in power performance was achieved merely by
Fuel and Energy Abstracts September 2006
363