检索结果-内蒙古大学图书馆

Performance of solar-assisted hybrid air-conditioning liquid desiccant system in Beirut

Performance of solar-assisted hybrid air-conditioning liquid...

First International Conference on Sustainable Energy, Planning and Technology in Relationship to the Environment, Energy and the Environment

作者： Ghaddar, N. Ghali, K. Najm, A. American University of Beirut Fac. of Engineering and Architecture Beirut 1107 2020 Lebanon Beirut Arab University Faculty of Engineering Beirut Lebanon

ISBN: (纸本)1853129704

In this work a model of a solar-operated liquid desiccant system (using calcium Chloride) for air dehumidification is developed. The desiccant system model is integrated with a solar heat source for performance evaluation at a wide range of recorded ambient conditions for Beirut city. The desiccant system of the current study is part of a hybrid desiccant-vapor compression system for a high latent load application, namely a small restaurant with an estimated cooling load of 11.39 TR (40 kW), including reheat. The relevant parameters of the desiccant system are optimized at peak load, and it is found out that there is an important energy saving if the ratio of the air flow rate in the regenerator to that in the dehumidifier is about 0.3 to 0.4. The COP of the desiccant unit is 0.45 for the restaurant. The size of the vapor compression unit of the restaurant is reduced to eight TR when supplemented by a desiccant system. The transient simulation of the solar desiccant system is performed for the entire cooling season. The solar fraction for the restaurant is 0.19, 0.38, and 0.54, for a collector area of 28.72, 57.44, and 86.16 m2, respectively. The economic benefit of the desiccant system is positive. For a gas price of 0.5638 $/kg, the payback period for the restaurant turned out to be immediate if the energy is supplied solely by natural gas, and 11 years if an 86.16 m2 solar collector is implemented to reduce the fuel consumption.

关键词： Solar energy

来源：评论

学校读者我要写书评

暂无评论

Application of Genetic Algorithms for Booster Chlorination in Water Supply Networks

Application of Genetic Algorithms for Booster Chlorination i...

引用

World Water and Environmental Resources Congress 2003

作者： Uçaner, M. Erkan Özdemir, Osman N. T.C. Basbakanlik GAP Idaresi B. Ankara Turkey Civil Engineering Department Fac. of Engineering and Architecture Gazi University Maltepe 06570 Ankara Turkey

ISBN: (纸本)0784406855

The chlorination of drinking water distribution networks is usually carried out at the supply source. However, chlorine may disappear in some portions or at distant points within a network. In this case, one or more booster chlorination stations must be built in the network in order to observe detectable chlorine residual at all levels of branching. Network hydraulic values, tank water levels and chlorine concentrations may vary over the course of one day because of changes in consumer demand. For this reason, the optimal location of a booster chlorination station, injection rates and scheduling must be considered together. In this research, the locations, injection rates and scheduling of chlorine booster stations were studied using genetic algorithms. The results indicate that booster disinfection can significantly increase the desired residual concentrations above the minimum limit while helping to reduce variability in nodal concentrations. The objectives were satisfied with a small increase in chlorine consumption compared to conventional disinfection only at the source. In order to find a hydraulic solution and chlorine concentration distribution in a network, EPANET software was used. In the solution phase, genetic algorithms and EPANET software were run interactively. The algorithm developed was used on an existing network given in the literature and solutions were compared with the current status of the network.

关键词： Water piping systems

来源：评论

学校读者我要写书评

暂无评论

On the design and development of high performance ADCs

Modelling, Measurement and Control A

引用

Modelling, Measurement and Control A 2003年第3-4期76卷 35-48页

作者： Balasubramanian, K. Dept. of Comp. Sci. and Engineering Fac. of Architecture and Engineering European University of Lefke Mersin 10 Turkey

An architecture for realizing high speed and large resolution ADC is proposed. The proposed architecture for the ADC is such that the complexity gets increased only a little extent when an attempt is made to improve the resolution for the enhanced word length of the ADC. By using just one 4-bit flash ADC in the structure we can build 32-bit high speed ADC trading off with the speed of a flash ADC to only a little extent. With the use of one 8-bit flash ADC for developing 32-bit ADC we can reach the speed nearer to that of the hypothetical 32-bit flash ADC, thereby we decrease the complexity of the 32-b ADC to such a low value required for practical implementation. As the speed realized by the architecture is far greater than the speed of conventional ADCs and as the complexity is reduced to a greater extent, these ADCs are promising to be useful for most modern requirements. With the use of such ADCs in computer IO peripherals, real time processing of high frequency signals would offer high precision results.

关键词： Analog to digital conversion

来源：评论

学校读者我要写书评

暂无评论

On the design and development of flash ADCs

Modelling, Measurement and Control A

引用

Modelling, Measurement and Control A 2003年第5-6期76卷 31-43页

作者： Balasubramanian, K. Dept. of Comp. Sci. and Engineering Fac. of Architecture and Engineering European University of Lefke Mersin 10 Turkey

As obviously known, flash ADC is the fastest ADC available in practice. The conventional flash ADCs are of low resolution types limiting the word size to 6 or 8 bits only, since a bit increase in the word length would result in doubling the complexity of the ADC. This paper proposes an architecture for building a high resolution flash ADC by employing one low resolution flash ADC in the structure. This architecture allows only a little increase in the complexity and in the overall conversion time as compared to the low resolution flash ADC employed in the structure. Two schemes of the architecture are reported in which one employs programmable gain amplifier and the other employs a residue amplifier. Circuits realizing flash ADCs of different word sizes are presented. Their conversion times and complexities are compared. Also, the use of a 32-bit flash ADC in a 32-bit microcomputer system is described.

关键词： Analog to digital conversion

来源：评论

学校读者我要写书评

暂无评论

Model reduction in the physical domain

Model reduction in the physical domain

引用

作者： Orbak, A.Y. Turkay, O.S. Eskinat, E. Youcef-Toumi, K. Department of Industrial Engineering Uludag University Bursa Turkey Department of Mechanical Engineering Fac. of Engineering and Architecture Yeditepe University K. Bakkalkoy/Kadikoy-81120 Istanbul Turkey Department of Mechanical Engineering Massachusetts Inst. of Technology Cambridge MA United States Department of Mechanical Engineering Bogazici University Istanbul Turkey

This paper is concerned with obtaining physical-based low-order approximations of linear physical systems. Low-order models possess some advantages, including the reduction of computational difficulty and understanding of the physics of the original system in a simpler manner. Previously, a number of methods have been suggested to develop suitable low-order approximations. However, most of these approaches do not reflect the relation between the mathematical model and the physical subsystems. Specifically, these techniques do not indicate which of the physical subsystems should be retained or eliminated in the reduced-order model. The proposed model reduction method is based on identifying subsystem types of a physical system using the bond graph method. These subsystems are then removed or retained based on the information from the physical system decomposition procedures and partial fraction expansion residues to obtain a reduced-order model. The physical model reduction procedure is verified on physical linear systems.

关键词： Linear systems

来源：评论

学校读者我要写书评

暂无评论

Using geometric shape variations to create an inverse model for a sheet metal process

Using geometric shape variations to create an inverse model ...

引用

作者： Rolfe, B.F. Cardew-Hall, M.J. Abdallah, S.M. West, G.A.W. School of Information Technology Deakin University Melbourne Vic 3125 Australia Department of Engineering Australian National University Canberra ACT Australia Fac. of Engineering and Architecture American University of Beirut Lebanon School of Computing Curtin University of Technology Perth WA Australia

The output of the sheet metal forming process is subject to much variation. This paper develops a method to measure shape variation in channel forming and relate this back to the corresponding process parameter levels of the manufac.uring set-up to create an inverse model. The shape variation in the channels is measured using a modified form of the point distribution model (also known as the active shape model). This means that channels can be represented by a weighting vector of minimal linear dimension that contains all the shape variation information from the average formed channel. The inverse models were created using classifiers that related the weighting vectors to the process parameter levels for the blank holder force (BHF), die radii (DR) and tool gap (TG) of the parameters. Several classifiers were tested: linear, quadratic Gaussian and artificial neural networks. The quadratic Gaussian classifiers were the most accurate and the most consistent type of classifier over all the parameters.

关键词： Sheet metal

来源：评论

学校读者我要写书评

暂无评论

Neural networks for the calculation of bandwidth of rectangular microstrip antennas

引用

Applied Computational Electromagnetics Society Journal 2003年第2期18卷 110-120页

作者： Gultekin, S. Sinan Guney, Kerim Sagiroglu, Seref Selcuk University Fac. of Engineering and Architecture Department of Electric Engineering 42031 Konya Turkey Erciyes University Faculty of Engineering Department of Electronic Engineering 38039 Kayseri Turkey Erciyes University Faculty of Engineering Department of Computer Engineering 38039 Kayseri Turkey

Neural models for calculating the bandwidth of electrically thin and thick rectangular microstrip antennas, based on the multilayered perceptrons and the radial basis function networks, are presented. Thirteen learning algorithms, the conjugate gradient of Fletcher-Reeves, Levenberg-Marquardt, scaled conjugate gradient, resilient backpropagation, conjugate gradient of Powell-Beale, conjugate gradient of Polak-Ribiére, bayesian regularization, one-step secant, backpropagation with adaptive learning rate, Broyden-Fletcher-Goldfarb-Shanno, backpropagation with momentum, directed random search and genetic algorithm, are used to train the multilayered perceptrons. The radial basis function network is trained by the extended delta-bar-delta algorithm. The bandwidth results obtained by using neural models are in very good agreement with the experimental results available in the literature. When the performances of neural models are compared with each other, the best results for training and test were obtained from the multilayered perceptrons trained by the conjugate gradient of Powell-Beale and Broyden-Fletcher-Goldfarb-Shanno algorithms, respectively.

关键词： Microstrip antennas

来源：评论

学校读者我要写书评

暂无评论

A control-oriented polytropic model of SI engine intake manifold

A control-oriented polytropic model of SI engine intake mani...

引用

2003 ASME International Mechanical engineering Congress

作者： Deur, Joško Hrovat, Davor Petrić, Joško Šitum, Željko University of Zagreb Fac. of Mech. Eng./Nav. Architecture I. Lučića 5 HR-10000 Zagreb Croatia Ford Res. and Advanced Engineering MD 2036 P.O. Box 2053 Dearborn MI 48121-2053 United States

The paper presents experimental results which show significant changes of the intake manifold air temperature during fast tip-in/tip-out engine transients. An adequate two-state polytropic manifold model is developed and experimentally validated. An emphasis is on the derivation and parameterization of a time-variant structure of the heat transfer coefficient. The polytropic manifold model is extended to a three-state form for the more general case of different heat transfer properties for the manifold plenum and runners. An influence of the engine back flow on the runner thermal transients is observed. A simple extension of the three-state model with the back flow effect is proposed.

关键词： Engines

来源：评论

学校读者我要写书评

暂无评论

Modeling of an automotive planetary gear set based on Karnopp model for clutch friction

Modeling of an automotive planetary gear set based on Karnop...

引用

2003 ASME International Mechanical engineering Congress

作者： Deur, Joško Asgari, Jahan Hrovat, Davor University of Zagreb Fac. of Mech. Eng./Nav. Architecture I. Lučića 5 HR-10000 Zagreb Croatia Ford Res. and Advanced Engineering MD 2036 P.O. Box 2053 Dearborn MI 48121-2053 United States

Planetary gear sets of automotive automatic transmissions include several hydraulic and one-way clutches. Clutch friction is traditionally described by the generalized, Stribeck, speed-dependent static function approximated by a steep straight line in the zero-speed region (so-called classical friction model). Another approach based on the Karnopp clutch friction model is proposed in this paper. Simulation results for park/reverse engagement and 1-2 upshift shows that the proposed gear set modeling method compared to the classical friction model-based method yields significant improvement with respect to simulation time, as well as accuracy.

关键词： Gears

来源：评论

学校读者我要写书评

暂无评论

Non-linear wave load of ship in head waves

引用

Brodogradnja 2003年第2期51卷 147-157页

作者： Zamarin, Albert Prpić-Oršić, Jasna Čorić, Većeslav Faculty of Engineering University of Rijeka Vukovarska 58 51000 Rijeka Croatia Fac. of Mech. Eng./Nav. Architecture University of Zagreb Ivana Lučića 5 10000 Zagreb Croatia

A wave load numerical model in large amplitude waves is presented. Non-linearity arising from the ship motion at large amplitude waves cannot be neglected, especially in wave load, as in the case of a linear model. The main source of non-linearity, focused on in this work, involves time dependent hydrodynamic coefficients and excitation due to the changing of section draught because of ship motion and wave passing. The load problem was solved on harmonic waves in the frequency domain in a vertical longitudinal plane. Vertical shear force and vertical bending moment in head waves were analysed. Two methods were used for determining section hydrodynamic coefficients, conformal mapping and Frank Close Fit method. As the source for linear and nonlinear equation formulation for motion as well as for the wave load, the modified Salvensen-Tuck-Faltinsen strip theory was used. Gathered results in the form of non-linear transfer functions and longitudinal distribution of the wave load, showing the difference between hogging and sagging conditions, were compared with the results of the linear model and non-linear calculations from the available literature. The results are presented for the S175 container ship, and clearly show nonlinear effects In motion and hull load. The results can be further applied in the process of determining non-linear vertical hull girder load response in irregular head waves, and also as final data, in extreme load response prediction.

关键词： Conformal mapping

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：