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Energy supply for water electrolysis systems using wind and solar energy to produce hydrogen: a case study of Iran

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Frontiers in Energy 2019年第3期13卷 539-550页

作者： Mostafa REZAEI Ali MOSTAFAEIPOUR Mojtaba QOLIPOUR Mozhgan MOMENI industrial engineering department Yazd UniversityYazd ***Iran

Due to acute problems caused by fossil fuels that threaten the environment, conducting research on other types of energy carriers that are clean and renewable is of great importance. Since in the past few years hydrogen has been introduced as the future fuel, the aim of this study is to evaluate wind and solar energy potentials in prone areas of Iran by the Weibull distribution function (WDF) and the Angstrom-Prescott (AP) equation for hydrogen production. To this end, the meteorological data of solar radiation and wind speed recorded at 10 m height in the time interval of 3 h in a five-year period have been used. The findings indicate that Manjil and Zahedan with yearly wind and solar energy densities of 6004 (kWh/m2) and 2247 0cWh/m2), respectively, have the greatest amount of energy among the other cities. After examining three different types of commercial wind turbines and photovoltaic (PV) systems, it becomes clear that by utilizing one set of Gamesa G47 turbine, 91 kg/d of hydrogen, which provides energy for 91 car/week, can be produced in Manjil and will save about 1347 L of gasoline in the week. Besides, by installing one thousand sets of X21-345 PV systems in Zahedan, 20 kg/d of hydrogen, enough for 20 cars per week, can be generated and 296 L of gasoline can be saved. Finally, the RETScreen software is used to calculate the annual CO2 emission reduction after replacing gasoline with the produced hydrogen.

关键词： wind energy solar energy water electrolysis hydrogen production Weibull distribution function (WDF) Angstrom丒Prescott (AP) equation

A SINGLE-PERIOD INVENTORY SYSTEM WITH A GENERAL S-SHAPED UTILITY AND EXPONENTIAL DEMAND

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Journal of Systems Science and Systems engineering 2010年第2期19卷 227-236页

作者： Wei GENG1 Xiaobo ZHAO2 Deng GAO3 department of industrial engineering,Tsinghua university,Beijing 100084,China department of industrial engineering Tsinghua University Beijing China

We discuss a single-period inventory system with a general S-shaped utility function and exponential demand. It is shown that there exists a state-dependent order-up-to policy to be optimal. Behaviors of optimal polic... 详细信息

关键词： Inventory S-shaped utility function order-up-to policy

Nanoarchitectured LiMn_2O_4/Graphene/ZnO Composites as Electrodes for Lithium Ion Batteries

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Journal of Materials Science & Technology 2014年第5期30卷 427-433页

作者： Saad Aziz Jianqing Zhao Carrington Cain Ying Wang department of Mechanical & industrial engineering Louisiana State University

LiMn2O4 nanoparticles are facilely synthesized using a sol-gel processing method. Graphene is added to LiMn2O4 electrode aiming at increasing specific capacity and improving rate capability. In order to further improve cycling stability of LiMn2O4/graphene electrode, atomic layer deposition （ALD） is used to deposit ultrathin ZnO coating composed of six ZnO ALD layers and modify the surface of either LiMn2O4/graphene electrode or individual LiMn2O4 particles to form nanoarchitectured LiMn2O4/graphene/ZnO electrodes. Both ZnO-ALD-modified LiMn2O4/graphene electrodes demonstrate enhanced cycling performance at 1C, retaining the final discharge capacity above 122 mA h g 1 after 100 electrochemical cycles, which is higher than 115 mA h g-1 of pristine LiMn2O4/graphene electrode and 109 mA h g-1 of bare LiMn2O4 electrode. The improved electrochemical performance of nanoarchitectured LiMn2O4/graphene/ZnO electrodes can be attributed to the cooperative effects from high electronic conductivity of graphene sheets to facilitate electron transportation and effective protection of ZnO ALD coating to restrict Mn dissolution and electrolyte decomposition.

关键词： LiMn2O4/graphene nanocomposite Atomic layer deposition Cathode material Lithium ion battery

Evaluation of microstructure and mechanical properties of squeeze overcast Al7075-Cu composite joints

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China Foundry 2023年第1期20卷 29-39页

作者： Muhammad Waqas Hanif Ahmad Wasim Muhammad Sajid Salman Hussain Muhammad Jawad Mirza Jahanzaib department of industrial engineering University of Engineering and Technology TaxilaPunjabPakistan

Al7075-Cu composite joints were prepared by the squeeze overcast *** effects of melt temperature,die temperature,and squeeze pressure on hardness and ultimate tensile strength(UTS)of squeeze overcast Al7075-Cu composite joints were *** experimental results depict that squeeze pressure is the most significant process parameter affecting the hardness and *** optimal values of UTS(48 MPa)and hardness(76 HRB)are achieved at a melt temperature of 800℃,a die temperature of 250℃,and a squeeze pressure of 90 *** electron microscopy(SEM)shows that fractured surfaces show flatfaced morphology at the optimal experimental ***-dispersive spectroscopy(EDS)analysis depicts that the atomic weight percentage of Zn decreases with an increase in melt temperature and squeeze *** optimal mechanical properties of the Al7075-Cu overcast joint were achieved at the Al2Cu eutectic phase due to the large number of copper atoms that dispersed into the aluminum melt during the solidification process and the formation of strong intermetallic *** relational analysis integrated with the Taguchi method was used to develop an optimal set of control variables for multi-response parametric *** tests were performed to validate the effectiveness of the employed *** manufacturing of squeeze overcast Al7075-Cu composite joints at optimal process parameters delivers a great indication to acknowledge a new method for foundry practitioners to manufacture materials with superior mechanical properties.

关键词： squeeze overcast joints Al7075-Cu composite joints mechanical properties gray relational analysis Taguchi method

Effect of stepover and torch tilting angle on a repair process using WAAM

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Advances in Manufacturing 2022年第4期10卷 541-555页

作者： Francesco Baffa Giuseppe Venturini Gianni Campatelli Emanuele Galvanetto department of industrial engineering University of FlorenceFlorenceItaly

To sustain the transition to a greener economy and greener manufacturing,it is necessary to develop new approaches and technologies to repair metal components;this will result in a drastic reduction in energy and material *** this study,wire arc additive manufacturing(WAAM)was used to deposit a layer of new material on an existing surface,with the objective of finding the optimal configuration that maximized the layer quality and material *** parameters considered are the stepover among the deposited beads and the inclination of the torch with respect to the repaired *** inclination angle is crucial when repairing complex surfaces,like those of a mold,owing to accessibility issues,the torch cannot be maintained orthogonal to the surfaces along the entire *** configurations were tested in order to assess the quality of the materials in terms of the presence of material voids,depth of penetration,and the heat affected zone(HAZ)and to understand the effects of these variables on the material efficiency and thickness of the repairing *** should be noted that by adopting deposition parameters set to have a low heat input,the use of a tilting angle has beneficial effects on the quality of the deposited layer and the process *** and geometrical measurements were carried out to assess the effect of these two variables depositing a layer of plain carbon steel.

关键词： Wire arc additive manufacturing(WAAM) Repairing·Torch inclination Stepover Remanufacturing

Plasmon-enhanced Performance of Dye-sensitized Solar Cells Based on Electrodeposited Ag Nanoparticles

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Journal of Materials Science & Technology 2014年第1期30卷 1-7页

作者： Xinning Luan Ying Wang department of Mechanical & industrial engineering Louisiana State University

In the present work, pulse current deposition is used to deposit evenly distributed and uniformly sized Ag nanoparticles onto a TiO2 nanotube array as photoelectrode in dye-sensitized solar cells （DSSCs）, and the size and amount of loading Ag nanoparticles are controlled by the pulse deposition time. Due to the enhanced light absorption and electron-hole separation caused by plasmon effect, DSSCs based on Ag-modified TiO2 nanotube arrays show higher energy conversion efficiencies than those based on bare nanotubes with the same tube length. Particularly, DSSC based on nanotubes modified using pulse deposition time 1 s/3 s delivers the highest energy conversion efficiency of 1.68% and the largest short-circuit current of 4.37 mA/ cm2, while DSSC consisting of bare nanotubes exhibits efficiency of 1.20% and short-circuit current of 2.27 mA/cm2, which represents a 40% enhancement of cell efficiency in DSSC based on Ag-modified Ti02 nanotubes. It is also noted that overly long pulse deposition time will not further increase DSSC efficiency due to agglomeration of Ag particles. For example, when the pulse deposition time is increased to 2 s/6 s, DSSC based on Ag-modified nanotubes exhibits a lower efficiency of 1.42%. Moreover, high-concentration TiCI4 treatment on TiO2 nanotube arrays can further increase the energy conversion efficiencies to 3.82% and 2.61% for DSSC based on Ag-modified TiO2 nanotubes and DSSC based on bare TiO2 nanotubes, respectively, by significantly creating more surface area for dye loading.

关键词： TiO2 nanotube Dye-sensitized solar cell Pulse current deposition Ag nanoparticle TiCI4 treatment

Mathematical Modeling of Carbon Content and Intercritical Annealing Temperature in DP Steels by Factorial Design Method

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Journal of Iron and Steel Research International 2014年第7期21卷 715-722页

作者： Gülcan TOKTAS Alaaddin TOKTAS Aslan Deniz KARAOGLAN department of Mechanical engineering Balikesir University department of industrial engineering Balikesir University

2k factorial design is employed to find the mathematical relation between the carbon content and intercritical annealing temperature （IAT） in order to predict the responses namely martensite volume fraction （MVF）, microhardness （H）, yield strength （YS）, ultimate tensile strength （UTS）, total elongation （TEL）, yield ratio （YR） and Charpy impact energy （CIE） in dual phase （DP） steels. Steels containing different carbon contents （0.085% C and 0.380% C） had been chosen for this purpose. The main advantages of factorial design are its easy implementation and the effective computation compared with the other optimization techniques, which were employed for predicting mentioned responses in the literature. To verify the proposed approach based on factorial design, experiments for verification were performed. The results of the verification experiments and the mathematical models are in accordance with each other and the literature.

关键词： dual phase steel factorial design material property prediction carbon content intercritical annealingtemperature

Nonlinear oscillations of sigmoid functionally graded material plates moving in longitudinal direction

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Applied Mathematics and Mechanics(English Edition) 2017年第11期38卷 1533-1550页

作者： Yanqing WANG J.W.ZU department of Mechanics Northeastern University department of Mechanical and industrial engineering University of Toronto

Geometrically nonlinear oscillations are investigated on sigmoid functionally graded material （S-FGM） plates with a longitudinal speed. The material properties of the plates obey a sigmoid distribution rule along the thickness direction. Based on the D＇Alembert＇s principle, a nonlinear equation of motion is derived for the moving S-FGM plates, where the von K^rm^n nonlinear plate theory is adopted. Utilizing the Galerkin method, the equation of motion is discretized and solved via the method of harmonic bal- ance. The approximate analytical solutions are validated through the adaptive step-size fourth-order Runge-Kutta method. Besides, the stability of the steady-state solutions is examined. The results reveal that the mode interaction behavior can happen between the first two modes of the moving S-FGM plates, leading to a complex nonlinear frequency response. It is further found that the power-law index, the longitudinal speed, the exci- tation amplitude, and the in-plane pretension force can significantly affect the nonlinear frequency-response characteristics of longitudinally traveling S-FGM plates.

关键词： sigmoid functionally graded material (S-FGM) plate moving nonlinearoscillation method of harmonic balance frequency response

Analytical analysis for vibration of longitudinally moving plate submerged in infinite liquid domain

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Applied Mathematics and Mechanics(English Edition) 2017年第5期38卷 625-646页

作者： Yanqing WANG J.W.ZU department of Mechanics Northeastern University department of Mechanical and industrial engineering University of Toronto

The vibration of a longitudinally moving rectangular plate submersed in an infinite liquid domain is studied analytically with the Rayleigh-Ritz method. The liquid is assumed to be incompressible, inviscid, and irrotational, and the velocity potential is used to describe the fluid velocity in the whole liquid field. The classical thin plate theory is used to derive mechanical energies of the traveling plate. As derivative of transverse displacement with respect to time in the compatibility condition equation exists, an exponential function is introduced to depict the dynamic deformation of the moving plate. It is shown that this exponential function works well with the Rayleigh- Ritz method. A convergence study shows a quick convergence speed for the immersed moving plate. Furthermore, the parametric study is carried out to demonstrate the effect of system parameters including the moving speed, the plate location, the liquid depth, the plate-liquid ratio, and the boundary condition. Results show that the above system parameters have significant influence on the vibration characteristics of the immersed moving plate. To extend the study, the method of added virtual mass incremental （AVMI） factor is used. The results show good agreement with those from the Rayleigh-Ritz method.

关键词： longitudinally moving plate fluid-structure interaction Rayleigh-Ritz method free vibration added virtual mass incremental (AVMI) factor method