The Experts below are selected from a list of 146214 Experts worldwide ranked by ideXlab platform
S Z Xu - One of the best experts on this subject based on the ideXlab platform.
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a zeolite 13x magnesium sulfate water sorption thermal energy storage device for domestic heating
Energy Conversion and Management, 2018Co-Authors: S Z Xu, R Z Wang, Lianyun WangAbstract:A sorption thermal energy storage (TES) device for domestic heating is presented in this article. The TES device adopts the new Design Scenario with valve-less adsorber and separate reservoir to eliminate the large-diameter vacuum valve for vapor flow, which decreases the cost, reduces the vapor flow resistance, and improves the system reliability. The device is charged by the electric heater, which can add much flexibility to the building energy system as well as contribute to the valley filling and peak shaving from demand side management. The newly developed composite sorbent of zeolite 13X/MgSO4/ENG-TSA (expanded natural graphite treated with sulfuric acid) with the salt mass fraction of 15% in the zeolite 13X/MgSO4 mixture is tested and used in the TES device (denoted as XM15/ENG-TSA). Experimental results show that the TES device with XM15/ENG-TSA has the energy storage density of 120.3kWh∙m−3 at 250°C charging temperature and 25–90°C discharging temperature. The temperature lift is as high as 65–69°C with the adsorption and evaporating temperatures of 25°C. The impregnation of MgSO4 dramatically improves the temperature rising rate during the adsorption heat recovery process, but the specific energy storage capacity of XM15/ENG-TSA is similar to that of zeolite 13X/ENG-TSA. The effect of the impregnated MgSO4 suggests that MgSO4 can be used for low-temperature TES to relieve the self-hindrance of the hydration reaction.
Lianyun Wang - One of the best experts on this subject based on the ideXlab platform.
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a zeolite 13x magnesium sulfate water sorption thermal energy storage device for domestic heating
Energy Conversion and Management, 2018Co-Authors: S Z Xu, R Z Wang, Lianyun WangAbstract:A sorption thermal energy storage (TES) device for domestic heating is presented in this article. The TES device adopts the new Design Scenario with valve-less adsorber and separate reservoir to eliminate the large-diameter vacuum valve for vapor flow, which decreases the cost, reduces the vapor flow resistance, and improves the system reliability. The device is charged by the electric heater, which can add much flexibility to the building energy system as well as contribute to the valley filling and peak shaving from demand side management. The newly developed composite sorbent of zeolite 13X/MgSO4/ENG-TSA (expanded natural graphite treated with sulfuric acid) with the salt mass fraction of 15% in the zeolite 13X/MgSO4 mixture is tested and used in the TES device (denoted as XM15/ENG-TSA). Experimental results show that the TES device with XM15/ENG-TSA has the energy storage density of 120.3kWh∙m−3 at 250°C charging temperature and 25–90°C discharging temperature. The temperature lift is as high as 65–69°C with the adsorption and evaporating temperatures of 25°C. The impregnation of MgSO4 dramatically improves the temperature rising rate during the adsorption heat recovery process, but the specific energy storage capacity of XM15/ENG-TSA is similar to that of zeolite 13X/ENG-TSA. The effect of the impregnated MgSO4 suggests that MgSO4 can be used for low-temperature TES to relieve the self-hindrance of the hydration reaction.
Armen Der Kiureghian - One of the best experts on this subject based on the ideXlab platform.
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simulation of orthogonal horizontal components of near fault ground motion for specified earthquake source and site characteristics
Earthquake Engineering & Structural Dynamics, 2018Co-Authors: Mayssa Dabaghi, Armen Der KiureghianAbstract:A method for simulating an ensemble of orthogonal horizontal near-fault ground motion components for a specified set of earthquake source and site characteristics is presented. We develop a parameterized stochastic model of the near-fault ground motion in two orthogonal horizontal directions. Near-fault ground motions may or may not contain a forward directivity pulse in at least one direction, and our final model will account for both pulselike and nonpulselike cases. In this paper we focus only on the pulselike motions. By fitting the model to a database of pulselike near-fault ground motions, we develop predictive equations for the model parameters in terms of the earthquake source and site characteristics, and we estimate the correlations between the model parameters. We use the predictive equations to generate sets of correlated model parameters and a corresponding ensemble of synthetic pairs of orthogonal horizontal near-fault ground motion components for a given Design Scenario specified in terms of earthquake and site characteristics. The resulting synthetic motions have the same statistical characteristics as the motions in the database, including the variability for the given set of earthquake source and site characteristics. Use of simulated motions is of particular interest in performance-based earthquake engineering due to scarcity of near-fault recordings.
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stochastic model for simulation of near fault ground motions
Earthquake Engineering & Structural Dynamics, 2017Co-Authors: Mayssa Dabaghi, Armen Der KiureghianAbstract:Summary A parameterized stochastic model of near-fault ground motion in two orthogonal horizontal directions is developed. The major characteristics of recorded near-fault ground motions are represented. These include near-fault effects of directivity and fling step; temporal and spectral non-stationarity; intensity, duration, and frequency content characteristics; directionality of components; and the natural variability of ground motions. Not all near-fault ground motions contain a forward directivity pulse, even when the conditions for such a pulse are favorable. The proposed model accounts for both pulse-like and non-pulse-like cases. The model is fitted to recorded near-fault ground motions by matching important characteristics, thus generating an ‘observed’ set of model parameters for different earthquake source and site characteristics. A method to generate and post-process synthetic motions for specified model parameters is also presented. Synthetic ground motion time series are generated using fitted parameter values. They are compared with corresponding recorded motions to validate the proposed model and simulation procedure. The use of synthetic motions in addition to or in place of recorded motions is desirable in performance-based earthquake engineering applications, particularly when recorded motions are scarce or when they are unavailable for a specified Design Scenario. Copyright © 2016 John Wiley & Sons, Ltd.
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simulation of orthogonal horizontal ground motion components for specified earthquake and site characteristics
Earthquake Engineering & Structural Dynamics, 2012Co-Authors: Sanaz Rezaeian, Armen Der KiureghianAbstract:SUMMARY A method for generating an ensemble of orthogonal horizontal ground motion components with correlated parameters for specified earthquake and site characteristics is presented. The method employs a parameterized stochastic model that is based on a time-modulated filtered white-noise process with the filter having time-varying characteristics. Whereas the input white-noise excitation describes the stochastic nature of the ground motion, the forms of the modulating function and the filter and their parameters characterize the evolutionary intensity and nonstationary frequency content of the ground motion. The stochastic model is fitted to a database of recorded horizontal ground motion component pairs that are rotated into their principal axes, a set of orthogonal axes along which the components are statistically uncorrelated. Model parameters are identified for each ground motion component in the database. Using these data, predictive equations are developed for the model parameters in terms of earthquake and site characteristics and correlation coefficients between parameters of the two components are estimated. Given a Design Scenario specified in terms of earthquake and site characteristics, the results of this study allow one to generate realizations of correlated model parameters and use them along with simulated white-noise processes to generate synthetic pairs of horizontal ground motion components along the principal axes. The proposed simulation method does not require any seed recorded ground motion and is ideal for use in performance-based earthquake engineering. Copyright © 2011 John Wiley & Sons, Ltd.
R Z Wang - One of the best experts on this subject based on the ideXlab platform.
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a zeolite 13x magnesium sulfate water sorption thermal energy storage device for domestic heating
Energy Conversion and Management, 2018Co-Authors: S Z Xu, R Z Wang, Lianyun WangAbstract:A sorption thermal energy storage (TES) device for domestic heating is presented in this article. The TES device adopts the new Design Scenario with valve-less adsorber and separate reservoir to eliminate the large-diameter vacuum valve for vapor flow, which decreases the cost, reduces the vapor flow resistance, and improves the system reliability. The device is charged by the electric heater, which can add much flexibility to the building energy system as well as contribute to the valley filling and peak shaving from demand side management. The newly developed composite sorbent of zeolite 13X/MgSO4/ENG-TSA (expanded natural graphite treated with sulfuric acid) with the salt mass fraction of 15% in the zeolite 13X/MgSO4 mixture is tested and used in the TES device (denoted as XM15/ENG-TSA). Experimental results show that the TES device with XM15/ENG-TSA has the energy storage density of 120.3kWh∙m−3 at 250°C charging temperature and 25–90°C discharging temperature. The temperature lift is as high as 65–69°C with the adsorption and evaporating temperatures of 25°C. The impregnation of MgSO4 dramatically improves the temperature rising rate during the adsorption heat recovery process, but the specific energy storage capacity of XM15/ENG-TSA is similar to that of zeolite 13X/ENG-TSA. The effect of the impregnated MgSO4 suggests that MgSO4 can be used for low-temperature TES to relieve the self-hindrance of the hydration reaction.
Kuilin Zhang - One of the best experts on this subject based on the ideXlab platform.
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assessing service Design options and strategies for overcoming barriers in the reorient intermodal freight transport corridor
PROCEEDINGS OF THE EUROPEAN TRANSPORT CONFERENCE (ETC) 2007 HELD 17-19 OCTOBER 2007 LEIDEN THE NETHERLANDS, 2007Co-Authors: Elise Millerhooks, V A Charman, Aaron T C Y Kozuki, Chungcheng Lu, Rahul Nair, Hani S. Mahmassani, Kuilin ZhangAbstract:The development of an international, intermodal freight transport system bridging the Nordic countries with south and southeastern European regions via central Europe (known as the REORIENT corridor) is considered. Interoperability of such a system is key to its success. Barriers to interoperability within the REORIENT corridor have been identified and strategies for overcoming, circumventing or neutralizing such barriers have been developed. In this paper, barrier-reducing operational strategy Scenarios are defined for given target years to assess a number of these strategies. Such strategy Scenarios may be operational, administrative, legal, and management-related. Additionally, service Design Scenarios corresponding to alternative intermodal rail freight services and associated attributes (e.g. rates, frequency, time in transit) are proposed to assess service options that could viably compete with truck. For each barrier-reducing operational strategy or service Design Scenario, numerical experiments were performed in a dynamic freight network simulation-assignment platform to assess the benefits of such strategies. The simulation-assignment platform was developed specifically for the analysis of multi-product intermodal freight transportation systems. At the core of the platform is a model framework for the mode-path assignment problem in multimodal freight transportation networks. The framework consists of three main components: multimodal freight network simulation component, multimodal freight assignment component, and a multiple product intermodal shortest path procedure. The freight network simulation component incorporates a bulk queueing model to evaluate transfer delay experienced by shipments at intermodal transfer terminals, classification yards, and ports. The multimodal freight assignment component determines the network flow pattern from a mode-path alternative set calculated by the multiple product intermodal shortest path procedure, based on the link travel costs and node transfer delays from the multimodal freight network simulation component. This model can represent individual shipment mode-path choice behavior, consolidation policy, conveyance link moving, and individual shipment terminal transfer in an iterative solution framework. This paper provides an overview of the experimental platform, describes the barrier-reducing operational strategy and service Design Scenarios proposed to assess strategies for overcoming identified barriers to seamless implementation, and presents findings from the experiments conducted to test the Scenarios. Implications of these findings for interoperability deployment in the REORIENT corridor are given. For the covering abstract see ITRD E137145.
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assessing service Design options and strategies for overcoming barriers in the reorient intermodal freight transport corridor
PROCEEDINGS OF THE EUROPEAN TRANSPORT CONFERENCE (ETC) 2007 HELD 17-19 OCTOBER 2007 LEIDEN THE NETHERLANDS, 2007Co-Authors: Elise Millerhooks, V A Charman, Aaron T C Y Kozuki, Chungcheng Lu, Rahul Nair, Hani S. Mahmassani, Kuilin ZhangAbstract:The development of an international, intermodal freight transport system bridging the Nordic countries with south and southeastern European regions via central Europe (known as the REORIENT corridor) is considered. Interoperability of such a system is key to its success. Barriers to interoperability within the REORIENT corridor have been identified and strategies for overcoming, circumventing or neutralizing such barriers have been developed. In this paper, barrier-reducing operational strategy Scenarios are defined for given target years to assess a number of these strategies. Such strategy Scenarios may be operational, administrative, legal, and management-related. Additionally, service Design Scenarios corresponding to alternative intermodal rail freight services and associated attributes (e.g. rates, frequency, time in transit) are proposed to assess service options that could viably compete with truck. For each barrier-reducing operational strategy or service Design Scenario, numerical experiments were performed in a dynamic freight network simulation-assignment platform to assess the benefits of such strategies. The simulation-assignment platform was developed specifically for the analysis of multi-product intermodal freight transportation systems. At the core of the platform is a model framework for the mode-path assignment problem in multimodal freight transportation networks. The framework consists of three main components: multimodal freight network simulation component, multimodal freight assignment component, and a multiple product intermodal shortest path procedure. The freight network simulation component incorporates a bulk queueing model to evaluate transfer delay experienced by shipments at intermodal transfer terminals, classification yards, and ports. The multimodal freight assignment component determines the network flow pattern from a mode-path alternative set calculated by the multiple product intermodal shortest path procedure, based on the link travel costs and node transfer delays from the multimodal freight network simulation component. This model can represent individual shipment mode-path choice behavior, consolidation policy, conveyance link moving, and individual shipment terminal transfer in an iterative solution framework. This paper provides an overview of the experimental platform, describes the barrier-reducing operational strategy and service Design Scenarios proposed to assess strategies for overcoming identified barriers to seamless implementation, and presents findings from the experiments conducted to test the Scenarios. Implications of these findings for interoperability deployment in the REORIENT corridor are given. For the covering abstract see ITRD E137145.