Search

Your search keyword '"Van, D"' showing total 81 results
Start Over Author "Van, D" Publisher elsevier bv
81 results on '"Van, D"'

3. Evaluation of flammable volume in the case of a catastrophic leak of R-32 from a rooftop unit

Author

Van D Baxter, Ahmad Abu-Heiba, Mingkan Zhang, Viral K. Patel, Ahmed Elatar, Omar Abdelaziz, and K. Dean Edwards

Subjects
Flammable liquid, 021110 strategic, defence & security studies, Leak, business.industry, 020209 energy, Mechanical Engineering, Nuclear engineering, Cooling cycle, 0211 other engineering and technologies, 02 engineering and technology, Building and Construction, Refrigerant, chemistry.chemical_compound, Volume (thermodynamics), chemistry, Air conditioning, 0202 electrical engineering, electronic engineering, information engineering, Environmental science, business, Roof, Global-warming potential
Abstract

With the effort to use alternative refrigerants with lower global warming potential (GWP), the majority of these alternative refrigerants are classified as slightly flammable. In this paper we report on the numerical evaluation of a catastrophic leak scenario of R-32 refrigerant from a 3-ton roof top air conditioning unit (RTU) which serves a 12.2 × 9.14 × 2.4 m room. A full rupture of a 6.35 mm (¼ inch) pipe downstream of the evaporator coil is simulated. Two separate cases with refrigerant releases of 1.81 kg and 3.62 kg charge have been studied. The two charges are released in 10.2 and 20.4 s, respectively, just after the end of a unit cooling cycle. The flammable volume inside the room existed only for about 40 s with a maximum flammable volume inside the room of 1.12% of the total room volume for the 3.62 kg charge case.

Published
2018
Full Text
View/download PDF

4. Development and validation of quasi-steady-state heat pump water heater model having stratified water tank and wrapped-tank condenser

Author

Van D Baxter, Ahmed Elatar, Bo Shen, and Kashif Nawaz

Subjects
020209 energy, Mechanical Engineering, Nuclear engineering, Design tool, 02 engineering and technology, Building and Construction, Energy factor, 021001 nanoscience & nanotechnology, Storage water heater, law.invention, System model, law, Heat exchanger, 0202 electrical engineering, electronic engineering, information engineering, Environmental science, Vapor-compression refrigeration, 0210 nano-technology, Condenser (heat transfer), Heat pump
Abstract

Heat pump water heater systems (HPWH) introduce new challenges for design and modeling tools, because they require vapor compression system balanced with a water storage tank. In addition, a wrapped-tank condenser coil has strong coupling with a stratified water tank, which leads HPWH simulation to a transient process. To tackle these challenges and deliver an effective, hardware-based HPWH equipment design tool, a quasi-steady-state HPWH model was developed based on the DOE/ORNL Heat Pump Design Model (HPDM). Two new component models were added via this study. One is a one-dimensional stratified water tank model, an improvement to the open-source EnergyPlus water tank model, by introducing a calibration factor to account for bulk mixing effect due to water draws, circulations, etc. The other is a wrapped-tank condenser coil model, using a segment-to-segment modeling approach. The HPWH system model was validated against available experimental data. After that, the model was used for parametric simulations to determine the effects of various design factors.

Published
2018
Full Text
View/download PDF

5. Performance optimization of CO2 heat pump water heater

Author

Van D Baxter, Kashif Nawaz, Bo Shen, Omar Abdelaziz, and Ahmed Elatar

Subjects
Parametric analysis, 020209 energy, Mechanical Engineering, Nuclear engineering, Stratification (water), Thermodynamics, 02 engineering and technology, Building and Construction, law.invention, Refrigerant, 020401 chemical engineering, law, Heat exchanger, 0202 electrical engineering, electronic engineering, information engineering, Environmental science, 0204 chemical engineering, Gas cooler, Heat pump water heater, Gas compressor, Heat pump
Abstract

A preliminary analysis was conducted to analyze the performance of a heat pump water heater (HPWH) that uses CO 2 as the refrigerant. A model to predict the performance was developed and calibrated based on the experimental data for an existing HPWH using a CO 2 refrigerant. The calibrated model was then used to run a parametric analysis in which factors such as water supply temperature, water circulation rate, tank stratification, and condenser configuration were considered. The performance of a commercial CO 2 system was compared with that of a similar system using R-134a as the refrigerant. It was found that CO 2 HPWH performance was comparable to that of an R-134a HPWH, more so for a separated gas cooler configuration. For comparable performance, the compressor size and the tube-in-tube heat exchanger (condenser/gas cooler) size were compared for CO 2 - and R-134a-based systems. The impact of the water circulation rate on the water temperature stratification in the tank, an essential requirement for higher performance for CO 2 HPWH systems was also investigated.

Published
2018
Full Text
View/download PDF

6. R290 (propane) and R600a (isobutane) as natural refrigerants for residential heat pump water heaters

Author

Van D Baxter, Bo Shen, Omar Abdelaziz, Ahmed Elatar, and Kashif Nawaz

Subjects
Waste management, 020209 energy, Energy Engineering and Power Technology, 02 engineering and technology, Energy factor, Industrial and Manufacturing Engineering, law.invention, Refrigerant, chemistry.chemical_compound, 020401 chemical engineering, chemistry, Propane, law, Air source heat pumps, 0202 electrical engineering, electronic engineering, information engineering, Isobutane, Environmental science, 0204 chemical engineering, Condenser (heat transfer), Gas compressor, Heat pump
Abstract

Growing awareness of the potential environmental impacts of various refrigerants has led to the phasedown of hydrofluorocarbon (HFC) refrigerants and to initiatives replacing HFCs with hydrocarbons or other environmentally friendlier fluids. This study evaluated the performance of R290 (propane) and R600a (isobutane) as substitutes for R134a (a HFC) for heat pump water heating (HPWH). A component-based model (calibrated against the experimental data) was used to predict the performance of the HPWH system. Key performance parameters such as unified energy factor, first hour rating, condenser discharge temperature, thermal stratification in the water tank, and total refrigerant charge were investigated. Analysis results suggest that both alternative refrigerants could provide comparable system performance to that of the baseline system containing R134a, with one caveat. As a drop-in alternative, R290 was found to be a better substitute for R134a, whereas R600a is expected to provide similar performance if the compressor size is increased to provide similar heating capacity. Significant reductions in system charge and lower condenser discharge temperatures were identified as additional benefits.

Published
2017
Full Text
View/download PDF

7. Air source integrated heat pump simulation model for EnergyPlus

Author

Van D Baxter, Joshua New, and Bo Shen

Subjects
Physics, Waste management, 020209 energy, Mechanical Engineering, Storage heater, Nuclear engineering, Hybrid heat, 02 engineering and technology, Building and Construction, Coefficient of performance, law.invention, Storage water heater, 020401 chemical engineering, law, Waste heat, Air source heat pumps, 0202 electrical engineering, electronic engineering, information engineering, 0204 chemical engineering, Electrical and Electronic Engineering, Control logic, Civil and Structural Engineering, Heat pump
Abstract

Air source integrated heat pump (ASIHP) is an air source, multi-functional space-conditioning unit with water heating function (WH), which can lead to significant energy savings by recovering condensing waste heat in the cooling season and providing dedicated or desuperheating heat pump water heating in the remaining months. This paper summarizes development of the EnergyPlus ASIHP model. It introduces the physics, sub-models, working modes, and control logic. Based on the model, building energy simulations were conducted to demonstrate greater than 50% annual energy savings, in comparison to a baseline heat pump with electric water heater, over 10 US cities, using the EnergyPlus quick-service restaurant template building. We assessed water heating energy saving potentials using ASIHP versus gas heating, and identified the climate zones where ASIHPs are promising. In addition, a grid integration strategy was investigated to reveal further energy saving and electricity cost reduction potentials, via increasing the water heating set-point temperature during off-peak hours and using larger water tanks.

Published
2017
Full Text
View/download PDF

10. A thermodynamics-based formulation for constitutive modelling using damage mechanics and plasticity theory

Author

Arash Mir, Giang D. Nguyen, Abdul Hamid Sheikh, and Van D. Vu

Subjects
Computer science, media_common.quotation_subject, Structure (category theory), Thermodynamics, 02 engineering and technology, Dissipation, Plasticity, 021001 nanoscience & nanotechnology, Range (mathematics), 020303 mechanical engineering & transports, 0203 mechanical engineering, Coupling (computer programming), Damage mechanics, Dissipative system, 0210 nano-technology, Function (engineering), Civil and Structural Engineering, media_common
Abstract

In this study, a generic formulation for constitutive modelling of engineering materials is developed, employing theories of plasticity and continuum damage mechanics. The development of the proposed formulation is carried out within the framework of thermodynamics with internal variables. In this regard, the complete constitutive relations are determined by explicitly defining a free energy potential and a dissipation potential. The focus is put on the rigour and consistency of the proposed formulation in accommodating the coupling between damage and plasticity, while keeping its structure sufficiently generic to be applicable to a wide range of engineering materials. In particular, by specifying the coupling between damage and plasticity in the dissipation function, a single generalised loading function that controls the simultaneous evolution of these dissipative mechanisms is obtained. The proposed formulation can be readily used for either enriching existing plasticity models with damage, or for the developments of new coupled damage-plasticity models. The promising features and the applications of the proposed formulation for describing the behaviour of different engineering materials are discussed in details.

Published
2017
Full Text
View/download PDF

11. A kinematically enhanced constitutive model for elastic and inelastic analysis of unidirectional fibre reinforced composite materials

Author

Van D. Vu, Abdul Hamid Sheikh, Giang D. Nguyen, and Luming Shen

Subjects
Materials science, Field (physics), business.industry, Mechanical Engineering, Constitutive equation, Micromechanics, 02 engineering and technology, Structural engineering, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Stress (mechanics), Matrix (mathematics), Nonlinear system, 020303 mechanical engineering & transports, 0203 mechanical engineering, Mechanics of Materials, Damage mechanics, General Materials Science, Deformation (engineering), Composite material, 0210 nano-technology, business, Civil and Structural Engineering
Abstract

A constitutive model with an enhanced strain field is developed in this study for predicting the behaviour of unidirectional fibre reinforced composite materials. The different deformation modes introduced in the enhanced strain field take into account of both the variation of strains and internal equilibrium conditions across the fibre-matrix interfaces in unidirectional composites. This opens rooms to accommodate the difference in the responses of fibre and matrix and allows both fibre and matrix to be represented separately by their own constitutive responses. The enriching deformation modes and internal equilibrium conditions lead to a combination of both upper and lower bound solutions on different components of the stress/strain tensors, resulting a homogenised macro response that compares well with experimental data and sophisticated homogenisation approaches in the literature. In addition, the key feature of the proposed approach is that the macro homogenised behaviour can be written in terms of incremental responses of both constituents and their interactions, facilitating the applications in both linear and nonlinear regimes of behaviour of both fibre and matrix. In parallel with this, a new coupled damage-plasticity model is also developed for the matrix behaviour and validated against experimental data of two resins, before being used in the proposed approach. The performance of the model and its promising features are demonstrated through verification with existing benchmarking models and validation with experimental data in both elastic and inelastic regimes.

Published
2017
Full Text
View/download PDF

12. Internally cooled membrane-based absorber for dehumidification and water heating: Validated model and simulation study

Author

Saeed Moghaddam, Kyle R. Gluesenkamp, Ahmad Abu-Heiba, Van D Baxter, Zhiyao Yang, Navin Kumar, and Zhiming Gao

Subjects
Desiccant, Materials science, Renewable Energy, Sustainability and the Environment, Cost effectiveness, 020209 energy, Nuclear engineering, Energy Engineering and Power Technology, 02 engineering and technology, Entropy (classical thermodynamics), Fuel Technology, Membrane, 020401 chemical engineering, Nuclear Energy and Engineering, Latent heat, 0202 electrical engineering, electronic engineering, information engineering, Working fluid, Absorption heat pump, 0204 chemical engineering, Parametric statistics
Abstract

This paper presents a comprehensive model for advanced membrane-based absorber components accounting for three separate fluid streams, one of them providing internal cooling, with complex flow patterns. The model was implemented with various liquid desiccants and their properties (including LiCl, CaCl2, and [emim][OMS] ionic liquid [IL]). The model has been validated using data from two laboratory prototype absorbers, one with CaCl2 as the working fluid and one with an IL as the working fluid. Entropy analysis was further carried out to verify the model and understand effect of internal cooling on the entropy variation of three fluid streams. The developed model and codes are expected to enable detailed configuration optimization and provide in-depth understanding of three-fluid heat and mass exchanger (HMX) performance. The paper also describes parametric studies of the HMX components in utilizing the latent heat removed in space cooling to heat water and numerically explores the unique benefit of its application in a semi-open absorption heat pump water heater. The results show that a single three-fluid HMX has the potential to achieve simultaneous dehumidification and water heating efficiently at cost effectiveness, particularly in hot and humid climates.

Published
2021
Full Text
View/download PDF

13. Hydrodynamic behavior of wrapped coil water heater tank

Author

Bo Shen, Kashif Nawaz, Van D Baxter, and Ahmed Elatar

Subjects
Fluid Flow and Transfer Processes, Materials science, Turbulence, Heat pump and refrigeration cycle, 0211 other engineering and technologies, Mixing (process engineering), 02 engineering and technology, Mechanics, law.invention, Volumetric flow rate, Refrigerant, 020401 chemical engineering, law, Heat transfer, 021108 energy, 0204 chemical engineering, Condenser (heat transfer), Heat pump
Abstract

A numerical investigation using computational fluid dynamics (CFD) has been carried out to analyze the thermal behavior of a water tank integrated to a heat pump water heating system (HPWH). The heat pump condenser is a long coil wrapped around the water tank and insulated from outside from which heat is transferred from the heat pump cycle into the water stored inside the tank. The simulated water tank has a capacity of about 170 L with the charging inlet located at the bottom segment of the tank and the discharging outlet located at the top segment of the tank like commercially available water heaters. The tank was simulated during charging/discharging process with isothermal boundary condition at the tank wall to represent the majority of the process for refrigerant condensation inside the heat pump condenser (excluding superheated and sub-cooled section). Three flow rates were selected to represent low, medium and high flow pattern. Both mean and turbulent flow properties were calculated and analyzed. Heat transfer mechanisms inside the tank are quantified by calculating Richardson and Peclet numbers to show the relative contribution of driving forces. The calculations show that advection is dominant over diffusion. Mixing factor is calculated and presented. It is found that the rate of increase of mixing is nonlinear with the increase in flow rate. Mixing increased by a factor of four when the flow rate increased by a factor of two.

Published
2020
Full Text
View/download PDF

14. Intensive blood pressure reduction with intravenous thrombolysis therapy for acute ischaemic stroke (ENCHANTED): an international, randomised, open-label, blinded-endpoint, phase 3 trial

Author

Anderson, Craig S, primary, Huang, Yining, additional, Lindley, Richard I, additional, Chen, Xiaoying, additional, Arima, Hisatomi, additional, Chen, Guofang, additional, Li, Qiang, additional, Billot, Laurent, additional, Delcourt, Candice, additional, Bath, Philip M, additional, Broderick, Joseph P, additional, Demchuk, Andrew M, additional, Donnan, Geoffrey A, additional, Durham, Alice C, additional, Lavados, Pablo M, additional, Lee, Tsong-Hai, additional, Levi, Christopher, additional, Martins, Sheila O, additional, Olavarria, Veronica V, additional, Pandian, Jeyaraj D, additional, Parsons, Mark W, additional, Pontes-Neto, Octavio M, additional, Ricci, Stefano, additional, Sato, Shoichiro, additional, Sharma, Vijay K, additional, Silva, Federico, additional, Song, Lili, additional, Thang, Nguyen H, additional, Wardlaw, Joanna M, additional, Wang, Ji-Guang, additional, Wang, Xia, additional, Woodward, Mark, additional, Chalmers, John, additional, Robinson, Thompson G, additional, Anderson, Craig S., additional, Lindley, Richard I., additional, Bath, Philip M., additional, Broderick, Joseph P., additional, Demchuk, Andrew M., additional, Donnan, Geoffrey A., additional, Durham, Alice C., additional, Lavados, Pablo M., additional, Martins, Sheila O., additional, Olavarria, Veronica V., additional, Pandian, Jeyaraj D., additional, Parsons, Mark W., additional, Pontes-Neto, Octavio M., additional, Sharma, Vijay K., additional, Thang, Nguyen H., additional, Wardlaw, Joanna M., additional, Robinson, Thompson G., additional, Kim, Jong S., additional, Stapf, Christian, additional, Simes, R. John, additional, Hankey, Graeme J., additional, Sandercock, Peter, additional, Bousser, Marie-Germaine, additional, Wong, K.S. Lawrence, additional, Scaria, Anish, additional, Hirakawa, Yoichiro, additional, Moullaali, Tom J., additional, Carcel, Cheryl, additional, Gordon, Penny, additional, Fuentes-Patarroyo, Sully X., additional, Benito, Dino, additional, Chen, Ruiqi, additional, Cao, Yongjun, additional, Kunchok, Amy, additional, Winters, Stephen, additional, Coutts, Shelagh, additional, Yoshimura, Sohei, additional, You, Shoujiang, additional, Yang, Jie, additional, Wu, Guojun, additional, Zhang, Shihong, additional, Manning, Lisa, additional, Mistri, Amit, additional, Haunton, Victoria, additional, Minhas, Jatinder, additional, Malavera, Alejandra, additional, Lim, Joyce, additional, Liu, Leibo, additional, Kumar, Namrata N., additional, Tay, Nicole, additional, Jenson, Kerry, additional, Richtering, Sarah, additional, Tucker, Sharon, additional, Knight, Elizabeth, additional, Ivanova, Elizaveta, additional, Thembani, Emma, additional, Odgers, Elizabeth, additional, Sanders, Elizabeth, additional, Small, Sabrina, additional, Vaghasiya, Ruchita, additional, Armenis, Manuela, additional, Donnelly, Paul, additional, Baig, Merza A., additional, Blacklock, Nick, additional, Naidu, Bala, additional, Monaghan, Helen, additional, Smith, Phillipa, additional, Glass, Parisa, additional, Bai, Xuejie, additional, Li, Qiancheng, additional, Zhu, Pingping, additional, Kong, Liang, additional, He, Ruihong, additional, Zhao, He, additional, Lv, Jiajie, additional, Jia, Haijing, additional, Xi, Zhen, additional, Cong, Yuhan, additional, Cui, Buliang, additional, Deng, Hua, additional, Guo, Ying, additional, He, Lingyu, additional, Jia, Ruolan, additional, Li, Nan, additional, Li, Wei, additional, Liu, Mengxiao, additional, Zhang, Meng, additional, Xu, Ziwei, additional, Zhang, Ting, additional, Zhao, Yan, additional, Gregory, Philip, additional, In, Yunjeong, additional, Kim, Su J., additional, Ahn, Jung E., additional, Kim, Sul H., additional, Hong, Young L., additional, González-McCawley, Francisca, additional, Martins, Magda C.O., additional, Portales, Bernardita, additional, Wang, Ching-Yi, additional, Ryu, Shan-Jen, additional, Aujla, Hardeep, additional, Lewin, Sue, additional, Kumar, Tracy, additional, Barrows, Sara, additional, Ebraimo, Ahtasam, additional, Uyen, Hong H., additional, Giang, Nguyen A., additional, Linh, Le T.M., additional, An, Le T.T., additional, Phuong, Do M., additional, Ngoc, Pham V.B., additional, Hang, Nguyen M., additional, Tran, Nguyen T.B., additional, Hien, Ha T.T., additional, Yen, Mai B., additional, Tram, Ngo T.B., additional, Truc, Tran T.T., additional, Hoa, Nguyen A., additional, Thuan, Nguyen T.B., additional, Oanh, Ha T.K., additional, Arora, Deepti, additional, Verma, Shweta J., additional, Krause, M., additional, Priglinger, M., additional, Day, S., additional, Jala, S., additional, Davies, L., additional, Ray, E., additional, Celestino, S., additional, Law, L.Y., additional, Wijeratne, T., additional, Ng, G., additional, Nagao, K., additional, Weiss, G., additional, Titton, N., additional, Batista, C., additional, Zãn, D., additional, Carbonera, L., additional, Ferreira, K., additional, Castro, R., additional, Martins Filho, R.K., additional, Carvalho, M., additional, Libardi, M., additional, Martins, G., additional, Fagundes, D., additional, Baron, G., additional, Boehringer, A., additional, Barbosa, J., additional, Bazan, R., additional, Braga, G., additional, Luvizutto, G., additional, Ribeiro, P., additional, Winckler, F., additional, Moro, C., additional, Longo, A., additional, Liberato, R., additional, Barbosa, R., additional, Magalhães, P., additional, Portal, M., additional, Martin, K., additional, Souza, A., additional, Cuervo, D., additional, Perin, D., additional, Marques, L., additional, Oliveira, F., additional, Battaglini, M., additional, Lourenço, F., additional, Silva, G., additional, Duarte, L., additional, Alves, M., additional, Sousa, J., additional, Uhehara, M., additional, Brunser, A., additional, Mazzón, E., additional, Spencer, M., additional, Acosta, I., additional, Rojo, A., additional, Rivas, R., additional, Klapp, C., additional, Carvallo, L., additional, Carvallo, P., additional, Mansilla, E., additional, Flores, J., additional, Alvarado, M., additional, Herrera, A., additional, Reyes, C., additional, Jurado, F., additional, Bustamante, G., additional, Bravo, L., additional, Matamala, J.M., additional, Guerrero, R., additional, Zhou, S., additional, Ping, L., additional, Liu, W., additional, Liu, L., additional, Tian, Y., additional, Xu, H., additional, Wang, J., additional, Wang, L., additional, Zhen, Z., additional, Zhang, J., additional, Yan, M., additional, Zhang, Q., additional, Tao, X., additional, Liu, C., additional, Shi, J., additional, Zhang, X., additional, Tai, L., additional, Xu, L., additional, Lu, H., additional, Nie, H., additional, Li, X., additional, Zhou, J., additional, Liu, Y., additional, Gong, P., additional, Zhao, H., additional, Li, R., additional, Wang, X., additional, Chen, Q., additional, Li, Y., additional, Wu, L., additional, Jia, L., additional, Guo, X., additional, Chen, G., additional, Lin, B., additional, Zhu, W., additional, Yang, K., additional, Zhang, Z., additional, Xie, C., additional, Wu, D., additional, Wang, Y., additional, Liu, D., additional, Liu, Z., additional, Liang, L., additional, Cao, Q., additional, Xia, J., additional, Weng, Y., additional, Li, J., additional, Xu, T., additional, Geng, D., additional, Yan, X., additional, Wang, D., additional, Zhao, N., additional, Tang, Z., additional, Yin, W., additional, Wang, S., additional, Huang, W., additional, Yang, Y., additional, Song, A., additional, Hao, Y., additional, Zhang, A., additional, Qiao, B., additional, Yang, J., additional, Yan, H., additional, Wei, X., additional, Tao, Z., additional, Liu, H., additional, Lv, Y., additional, Yang, H., additional, Han, L., additional, Mao, X., additional, Ge, L., additional, Zhang, Y., additional, He, S., additional, Jiang, J., additional, Wu, W., additional, Wang, H., additional, Yang, L., additional, Tang, Y., additional, Sun, H., additional, Li, F., additional, Li, G., additional, Sun, Y., additional, Zhang, H., additional, Wu, Y., additional, Huang, L., additional, Geng, C., additional, Jin, Z., additional, Zhu, J., additional, Zhang, F., additional, Zheng, R., additional, Shen, H., additional, Liu, F., additional, Chen, C., additional, Chen, S., additional, Zhou, L., additional, Hu, B., additional, Zou, Z., additional, Liu, J., additional, Chang, X., additional, Zhang, S., additional, Huang, Q., additional, Liu, X., additional, Liu, S., additional, He, W., additional, Feng, J., additional, Li, L., additional, Chen, X., additional, Zhuang, X., additional, Zheng, W., additional, Lai, Y., additional, Zhou, Y., additional, Duan, H., additional, Yang, Q., additional, Du, J., additional, Lin, Q, additional, Xu, E., additional, Zhan, L., additional, Wu, J., additional, Feng, X., additional, Wei, C., additional, He, J., additional, Wang, B., additional, Li, W, additional, Chen, P, additional, Guo, F, additional, Dai, H, additional, Dai, M, additional, Zeng, X., additional, Chen, B., additional, Long, F., additional, Su, Q., additional, Bao, B., additional, Wu, T., additional, Wu, X., additional, Shao, Y., additional, Li, S., additional, Xu, Y., additional, Castellanos, J.A., additional, Muñoz-Collazos, M., additional, Solano, E., additional, Leung, W.H.T., additional, Sureshbabu, S., additional, Sharma, S.N., additional, George, S., additional, Shekhar, S., additional, Singla, S., additional, Saini, L., additional, Sunita, -, additional, Kate, M., additional, Sarvotham, R., additional, William, A.G., additional, Deepak, A., additional, BK, M., additional, Benny, R., additional, Bolegave, V., additional, Basle, M., additional, Gore, S., additional, George, P., additional, Kumaravelu, S., additional, Rahamath, S., additional, Raj, P.G., additional, Devi, A.R., additional, Sharma, A., additional, Prajapati, J., additional, Parmar, M., additional, Patel, D., additional, Panchal, T., additional, Gorthi, S.P., additional, Prabhu, V., additional, Prabhu, A., additional, Chandran, V., additional, Chatterjee, A., additional, Nair, R., additional, Nambiar, V.K., additional, TS, D., additional, TP, S., additional, Ajai, V., additional, Paul, S., additional, Natarajan, P.C., additional, Chittibabu, D., additional, Borah, N.C., additional, Ghose, M., additional, Choudhury, N., additional, Gohain, P., additional, Kalita, K., additional, Duberkar, D., additional, Pawar, N., additional, Bhaviskar, R., additional, Caterbi, E., additional, Cenciarelli, S., additional, Condurso, R., additional, Gallinella, E., additional, Greco, L., additional, Marando, C., additional, Mastrocola, S., additional, Mattioni, A., additional, Sacchini, E., additional, Sicilia, I., additional, Gallina, A., additional, Giannandrea, D., additional, Marsili, E., additional, Mazzoli, T., additional, Padiglioni, C., additional, Corea, F., additional, Guidubaldi, A., additional, Micheli, S., additional, Barbi, M., additional, Kim, J., additional, Song, H.J., additional, Jeong, H.S., additional, Lim, J.G., additional, Park, S.M., additional, Lee, K.B., additional, Hwang, H.W., additional, Kwon, S.U., additional, Kang, D.W., additional, Kim, Y.J., additional, Kim, B.J., additional, Park, J.M., additional, Kang, K., additional, Kim, B., additional, Kwon, O., additional, Kim, Y.W., additional, Lee, J.J., additional, Hwang, Y.H., additional, Kwon, H.S., additional, Koo, J., additional, Lee, K., additional, Kim, T., additional, Ahn, A., additional, Rha, J.H., additional, Park, H.K., additional, Yoon, C.W., additional, Chan, B., additional, Teoh, H.L., additional, Paliwal, P., additional, Wong, L.Y.J., additional, Chen, J.T., additional, De Silva, D.A., additional, Chang, H.M., additional, Fabiaña, N., additional, Marti, J., additional, Delgado, R., additional, Martínez, A., additional, Prats, L., additional, Camps, P., additional, Liou, C.W., additional, Tan, T.Y., additional, Liu, C.F., additional, Cheng, H.H., additional, Po, H.L., additional, Lin, Y.J., additional, Chou, C.L., additional, Lin, C.H., additional, Yen, C.C., additional, Chang, Y.T., additional, Hsu, Y.T., additional, Lee, J.D., additional, Lee, M., additional, Huang, Y.C., additional, Wu, C.Y., additional, Suwanwela, N.C., additional, Chutinet, A., additional, Likitjaroen, Y., additional, Roongpiboonsopit, D., additional, Charnwut, S., additional, Dyker, A., additional, Hossain, M., additional, Muddegowda, G.K., additional, Sanyal, R., additional, Roffe, C., additional, Natarajan, I., additional, Finney, K., additional, Sztriha, L., additional, Teo, J., additional, Chan, F.K., additional, Lim, J., additional, Chitando, B., additional, Clarke, B., additional, Patel, B., additional, Khan, U., additional, Ghatala, R., additional, Trippier, S., additional, Kalra, L., additional, Manawadu, D., additional, Sikondari, N., additional, Aeron-Thomas, J., additional, Sunman, W., additional, Wilkes, G., additional, Richardson, C., additional, Buch, A., additional, Jackson, B., additional, Halse, O., additional, Mashate, S., additional, Wilding, P., additional, Nguyen, V., additional, Qadiri, M.R., additional, Rashed, K., additional, Board, S., additional, Buckley, C., additional, Smith, C., additional, James, M., additional, Keenan, S., additional, Bouring, A., additional, England, T., additional, Donnelly, R., additional, Scott, J., additional, Maddula, M., additional, Beavan, J., additional, Perry, R., additional, Francia, N., additional, Watchhurst, C., additional, Banaras, A., additional, Ashton, A., additional, Mistri, A., additional, Musarrat, K., additional, Eveson, D., additional, Kallingal, J., additional, Perez, J., additional, Harrison, L., additional, Marsden, T., additional, Furnace, J., additional, Clarke, R., additional, Reid, J., additional, Warburton, E., additional, Macleod, M.J., additional, Mitchell, J., additional, Day, D., additional, Church, N., additional, Amis, E., additional, Price, C., additional, Rodgers, H., additional, Whiting, R., additional, Hussain, M., additional, Harvey, M., additional, Brown, S., additional, Foot, J., additional, Tryambake, D., additional, Broughton, D., additional, Bergin, A., additional, Annamalai, A., additional, Dixon, L., additional, Weir, N., additional, Blank, C., additional, Harkness, K., additional, Ali, A., additional, Richards, E., additional, Stocks, K., additional, Bruce, D.W., additional, Wani, M., additional, Anjum, T., additional, Krishnan, M., additional, Nguyen Huy, T., additional, Le Tuan, A. Truong, additional, Cam, L. Dam Thi, additional, Kim, T. Ngo Thi, additional, Nguyen, B. Pham, additional, Dat, A. Nguyen, additional, Van, C. Nguyen, additional, Duy, T. Mai, additional, Viet, P. Dao, additional, Tien, D. Nguyen, additional, Van, T. Vo, additional, Le Kim, K., additional, Ngoc, T. Bui, additional, Le Thanh, T. Tran, additional, Hoanh, S. Nguyen, additional, Phuoc, S. Pham, additional, Van, T. Tran, additional, Thi, B. Doan, additional, Thu, H. Nguyen Thi, additional, Duy, M. Nguyen, additional, and Van, D. Ngo, additional

Published
2019
Full Text
View/download PDF

16. Data, exergy, and energy analyses of a vertical-bore, ground-source heat pump for domestic water heating under simulated occupancy conditions

Author

Van D Baxter, Moonis R. Ally, Anthony C Gehl, and Jeffrey D Munk

Subjects
Exergy, Engineering, Occupancy, business.industry, Geothermal energy, Renewable heat, Environmental engineering, Energy Engineering and Power Technology, Industrial and Manufacturing Engineering, Renewable energy, law.invention, law, Benchmark (surveying), business, Water use, Heat pump
Abstract

Evidence is provided to support the view that 68%–76% of the energy required to produce domestic hot water may be extracted from the ground which serves as a renewable energy resource. The case refers to a 345 m 2 research house located in Oak Ridge, Tennessee, 36.01°N 84.26°W in a mixed-humid climate with HDD of 2218 °C-days (3993 °F-days) and CDD of 723 °C-days (1301 °F-days). The house is operated under simulated occupancy conditions in which the hot water use protocol is based on the Building America Research Benchmark Definition which captures the water consumption lifestyles of the average family in the United States. The 5.3 kW (1.5-ton) water-to-water ground source heat pump (WW-GSHP) shared the same vertical bore with a separate 7.56 KW water-to-air ground source heat pump for space conditioning the same house. Energy and exergy analysis of data collected continuously over a twelve month period provide performance metrics and sources of inherent systemic inefficiencies. Data and analyses are vital to better understand how WW-GSHPs may be further improved to enable the ground to be used as a practical renewable energy resource.

Published
2015
Full Text
View/download PDF

17. Exergy analysis of a two-stage ground source heat pump with a vertical bore for residential space conditioning under simulated occupancy

Author

Moonis R. Ally, Van D Baxter, Anthony C Gehl, and Jeffrey D Munk

Subjects
Exergy, Engineering, business.industry, Mechanical Engineering, Geothermal energy, Geothermal heating, Renewable heat, Environmental engineering, Building and Construction, Management, Monitoring, Policy and Law, law.invention, Renewable energy, General Energy, Energy development, Energy(all), law, media_common.cataloged_instance, European union, business, media_common, Heat pump, Civil and Structural Engineering
Abstract

This twelve-month field study analyzes the performance of a 7.56 W (2.16-ton) water-to-air-ground source heat pump (WA-GSHP) to satisfy domestic space conditioning loads in a 253 m2 house in a mixed-humid climate in the United States. The practical feasibility of using the ground as a source of renewable energy is clearly demonstrated. Better than 75% of the energy needed for space heating was extracted from the ground. The average monthly electricity consumption for space conditioning was only 40 kW h at summer and winter thermostat set points of 24.4 °C and 21.7 °C, respectively. The WA-GSHP shared the same 94.5 m vertical bore ground loop with a separate water-to-water ground-source heat pump (WW-GSHP) for meeting domestic hot water needs in the same house. Sources of systemic irreversibility, the main cause of lost work, are identified using Exergy and energy analysis. Quantifying the sources of Exergy and energy losses is essential for further systemic improvements. The research findings suggest that the WA-GSHPs are a practical and viable technology to reduce primary energy consumption and greenhouse gas emissions under the IECC 2012 Standard, as well as the European Union (EU) 2020 targets of using renewable energy resources.

Published
2015
Full Text
View/download PDF

19. Exergy and energy analysis of a ground-source heat pump for domestic water heating under simulated occupancy conditions

Author

Van D Baxter, Jeffrey D Munk, Moonis R. Ally, and Anthony C Gehl

Subjects
Exergy, Occupancy, business.industry, Mechanical Engineering, Renewable heat, Environmental engineering, Thermodynamics, Building and Construction, Energy consumption, Renewable energy, law.invention, law, Environmental science, Ground loop (electricity), business, Water use, Heat pump
Abstract

This paper presents analysis of a 5.275 kW (1.5-ton) water-to-water ground source heat pump (WW-GSHP) satisfying hot water needs in a 345 m 2 research house operated under simulated occupancy conditions. The hot water use protocol from the Building America Research Benchmark Definition claims to capture the living habits of the average American household and its impact on energy consumption. Energy and exergy analyses provide insight on system efficiency and sources of irreversibility, the main cause of wasted energy. The WW-GSHP shared the ground loop with a 7.56 kW water to air ground source heat pump (WA-GSHP) to space condition the same house. Understanding the performance of GSHPs is vital if the ground is to be used as a viable renewable energy resource.

Published
2013
Full Text
View/download PDF

20. Exergy analysis and operational efficiency of a horizontal ground-source heat pump system operated in a low-energy test house under simulated occupancy conditions

Author

Van D Baxter, Anthony C Gehl, Jeffrey D Munk, and Moonis R. Ally

Subjects
Exergy, business.industry, Mechanical Engineering, Geothermal energy, Nuclear engineering, Thermal resistance, Thermodynamics, Building and Construction, Coefficient of performance, Renewable energy, law.invention, law, Solar gain, Environmental science, Ground loop (electricity), business, Heat pump
Abstract

This paper presents data, analyses, measures of performance, and conclusions for a ground-source heat pump (GSHP) providing space conditioning to a 345 m 2 house whose envelope is made of structural insulated panels. The entire house thermal load with R SI -3.7 (R US -21) walls, triple-pane windows (U-factor of 1.64 W m −2 K (0.29 Btu h −1 ft −2 °F −1 )) and solar heat gain coefficient of 0.25, a roof assembly with overall thermal resistance of about R SI -8.8 (R US -50), and low leakage rates of 0.74 ACH at 50 Pa, was satisfied with a 2.16 ton (7.56 kW) GSHP unit. Coefficient of performance is calculated on the basis of the total power input (including duct, ground loop, and control power losses). Exergy analysis provides a true measure of how closely actual performance approaches the ideal, and it unequivocally identifies, better than energy analysis does, the sources and causes of lost work — the root cause of system inefficiencies and wasted energy.

Published
2012
Full Text
View/download PDF

21. The Utility of Sulfonate Salts in Drug Development

Author

David P. Elder, Steve Eyley, Karine Jacq, Kevin L. Facchine, Pat Sandra, Ed Delaney, Rolf Schulte Oestrich, Frank David, Van D. Reif, and Andrew Teasdale

Subjects
chemistry.chemical_classification, Active ingredient, Genotoxic impurities, Pharmaceutical Science, Sulfonic acid, chemistry.chemical_compound, Sulfonate, chemistry, Drug development, Pharmaceutical technology, Drug Discovery, Marketed products, Animals, Humans, Organic chemistry, Salts, Sulfonic Acids, Salt formation
Abstract

The issue of controlling genotoxic impurities in novel active pharmaceutical ingredients (APIs) is a significant challenge. Much of the current regulatory concern, has been focused on the formation and control of genotoxic sulfonate esters. This is linked with the withdrawal of Viracept (Nefinavir mesilate) from European markets in mid-2007, over concerns about elevated levels of ethyl methanesulfonate (EMS). This issue has resulted in calls from European regulators to assess risk mitigation strategies for all marketed products employing a sulfonic acid counter-ion to ensure that the sulfonate esters that could be potentially formed are controlled to threshold of toxicological concern (TTC)-based limits. This has even led to calls to avoid sulfonic acids as salt counter-ions. However, sulfonic acid salts possess a range of properties that are useful to both synthetic and formulation chemists. Whilst sulfonate salts are not a universal panacea to some of the problems of salt formation they do offer significant advantages as alternatives to other salt forming moieties under certain circumstances. This review thus sets out to define some of the advantages provided through utilization of sulfonic acids, explaining the importance of their retention as part of a thorough salt selection process.

Published
2010
Full Text
View/download PDF

25. Multi-item spare parts systems with lateral transshipments and waiting time constraints

Author

van Gjjan Geert-Jan Houtum, van D Oudheusden, Hartanto Wong, Dirk Cattrysse, and Operations Planning Acc. & Control

Subjects
Inventory control, Information Systems and Management, General Computer Science, Operations research, Total cost, Computer science, Heuristic, Stockout, Logistics management, Management Science and Operations Research, Industrial and Manufacturing Engineering, Transshipment, symbols.namesake, Lagrangian relaxation, Modeling and Simulation, Spare part, symbols, Stock control
Abstract

This paper deals with the analysis of a multi-item, continuous review model of two-location inventory systems for repairable spare parts, used for expensive technical systems with high target availability levels. Lateral and emergency shipments occur in response to stockouts. A continuous review basestock policy is assumed for the inventory control of the spare parts. The objective is to minimize the total costs for inventory holding, lateral transshipments and emergency shipments subject to a target level for the average waiting time per demanded part at each of the two locations. A solution procedure based on Lagrangian relaxation is developed to obtain both a lower bound and an upper bound on the optimal total cost. The upper bound follows from a heuristic solution. An extensive numerical experiment shows an average gap of only 0.31% between the lower and upper bounds. The experiment also gives insights into the relative improvement achieved by applying lateral transshipments and or the system approach. We also apply the proposed model to actual data from an air carrier company.

Published
2006
Full Text
View/download PDF

26. Determination of isepamicin sulfate and related compounds by high performance liquid chromatography using evaporative light scattering detection

Author

Van D. Reif, R Vogel, and K DeFillipo

Subjects
Light, Calibration curve, Molecular Sequence Data, Clinical Biochemistry, Analytical chemistry, Pharmaceutical Science, Sensitivity and Specificity, High-performance liquid chromatography, Analytical Chemistry, chemistry.chemical_compound, Drug Discovery, Carbohydrate Conformation, medicine, Scattering, Radiation, Derivatization, Chromatography, High Pressure Liquid, Spectroscopy, Antibacterial agent, Detection limit, Chromatography, Reproducibility of Results, Repeatability, Reversed-phase chromatography, Anti-Bacterial Agents, Carbohydrate Sequence, chemistry, Gentamicins, Isepamicin, medicine.drug
Abstract

A simple reversed phase high performance liquid chromatographic method was developed for the analysis of isepamicin sulfate. The use of evaporative light scattering detection eliminates the need for sample derivatization. Separation of the isepamicin aminoglycoside from structurally similar related compounds was achieved using two Waters X-Terra RP18 columns connected in tandem at 10 degrees C. The assay of isepamicin sulfate and the estimation of its impurities was accomplished using external standard calibration curves at two sample concentrations: 1.6 mg ml(-1) for the analysis of isepamicin sulfate and 8.0 mg ml(-1) for the estimation of lower level impurities. The limit of detection was 0.1%. The specificity, assay linearity, low level assay linearity and assay repeatability were also investigated.

Published
2001
Full Text
View/download PDF

27. Determination of enantiomers in a synthetic argininal peptide using capillary zone electrophoresis and high-performance liquid chromatography

Author

Niya Dan, David J. S. Tsai, Ravindran Ganesan, Keith G Flood, and Van D. Reif

Subjects
chemistry.chemical_classification, Chromatography, Dipeptide, Cyclodextrin, Organic Chemistry, Temperature, Diastereomer, Electrophoresis, Capillary, Stereoisomerism, General Medicine, Reversed-phase chromatography, Buffers, Hydrogen-Ion Concentration, Arginine, Biochemistry, High-performance liquid chromatography, Analytical Chemistry, chemistry.chemical_compound, Capillary electrophoresis, chemistry, Indicators and Reagents, Enantiomer, Peptides, Derivatization, Chromatography, High Pressure Liquid
Abstract

SCH 201781 is a synthetic argininal peptide containing two chiral centers and an aromatic sulfonamide group. It can exist as four reversible forms, the aldehyde, the hydrate, and two diastereomeric aminals. Capillary zone electrophoresis (CZE) and reversed-phase high-performance liquid chromatographic (HPLC) methods were developed to separate and quantitate the enantiomers in SCH 201781. Comparable results were obtained using both methods. The CZE method uses direct injection, while the HPLC method requires a precolumn derivatization and is more time consuming. The CZE method provides superior sensitivity to the HPLC method. Both methods were shown to be precise and reproducible.

Published
2000
Full Text
View/download PDF

34. Rôle du NO exhalé dans la prise en charge thérapeutique des patients asthmatiques dans les pays émergents – exemple du Vietnam

Author

Duong-Quy, S., primary, Hua-Huy, T., additional, Le-Dong, N.N., additional, Phan Van, D., additional, Tran Dinh, H., additional, Doan Thi Quynh, N., additional, Le Quang, K., additional, Nguyen Quoc, B., additional, Mai Huu Thanh, B., additional, Duong Quy, B., additional, Vu Van, C., additional, Duong-Ngo, C., additional, Raffard, M., additional, Aelony, Y., additional, Martin, F., additional, Grignet, J.-P., additional, Homasson, J.-P., additional, and Dinh-Xuan, A.T., additional

Published
2012
Full Text
View/download PDF

36. The Utility of Sulfonate Salts in Drug Development

Author

Elder, David P., primary, Delaney, Ed, additional, Teasdale, Andrew, additional, Eyley, Steve, additional, Reif, Van D., additional, Jacq, Karine, additional, Facchine, Kevin L., additional, Oestrich, Rolf Schulte, additional, Sandra, Patrick, additional, and David, Frank, additional

Published
2010
Full Text
View/download PDF

42. Development and validation of an automated static headspace gas chromatography–mass spectrometry (SHS-GC–MS) method for monitoring the formation of ethyl methane sulfonate from ethanol and methane sulfonic acid

Author

Jacq, Karine, primary, Delaney, Ed, additional, Teasdale, Andrew, additional, Eyley, Steve, additional, Taylor-Worth, Karen, additional, Lipczynski, Andrew, additional, Reif, Van D., additional, Elder, David P., additional, Facchine, Kevin L., additional, Golec, Simon, additional, Oestrich, Rolf Schulte, additional, Sandra, Pat, additional, and David, Frank, additional

Published
2008
Full Text
View/download PDF

45. PQRI Recommendations on Particle-Size Analysis of Drug Substances Used in Oral Dosage forms

Author

Snorek, Sharon M., primary, Bauer, John F., additional, Chidambaram, Nallaperumal, additional, Doub, William H., additional, Duffy, Eric P., additional, Etzler, Frank M., additional, Kelly, Richard N., additional, Lane, Justin J., additional, Mueller, Ronald L., additional, Prasanna, Hullahalli R., additional, Pujara, Chetan P., additional, Reif, Van D., additional, Scarlett, Brian, additional, Stowell, Joseph G., additional, and Toma, Pascal H., additional

Published
2007
Full Text
View/download PDF

50. Oscillatory systems in mitochondria

Author

Lester Packer and Van D. Gooch

Subjects
Sucrose, Time Factors, Biophysics, Mitochondria, Liver, Acetates, Mitochondrion, Biochemistry, Phosphates, Text mining, Animals, Anaerobiosis, Columbidae, Adenosine Triphosphatases, business.industry, Chemistry, Myocardium, Osmolar Concentration, Biological Transport, Succinates, Hydrogen-Ion Concentration, Mitochondria, Mitochondria, Muscle, Rats, Cell biology, Kinetics, Microscopy, Electron, Energy Transfer, business
Published
1974
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results