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Modeling analysis on solar steam generator employed in multi-effect distillation (MED) system

Zhaorui ZHAO, Bao YANG, Ziwen XING

《能源前沿(英文)》 2019年 第13卷 第1期   页码 193-203 doi: 10.1007/s11708-019-0608-0

摘要: Recently the porous bilayer wood solar collectors have drawn increasing attention because of their potential application in solar desalination. In this paper, a thermodynamic model has been developed to analyze the performance of the wood solar collector. A modeling analysis has also been conducted to assess the performance and operating conditions of the multiple effect desalination (MED) system integrated with the porous wood solar collector. Specifically, the effects of operating parameters, such as the motive steam temperature, seawater flow rate, input solar energy and number of effects on the energy consumption for each ton of distilled water produced have been investigated in the MED desalination system combined with the bilayer wood solar steam generator. It is found that, under a given operating condition, there exists an optimum steam generation temperature of around 145°C in the wood solar collector, so that the specific power consumption in the MED system reaches a minimum value of 24.88 kWh/t. The average temperature difference is significantly affected by the solar heating capacity. With the solar capacity increasing from 50 kW to 230 kW, the average temperature difference increases from 1.88°C to 6.27°C. This parametric simulation study will help the design of efficient bilayer wood solar steam generator as well as the MED desalination system.

关键词: solar energy     steam generating     multi-effect desalination    

Multi-effect anthraquinone-based polyimide enclosed SnO/reduced graphene oxide composite as high-performance

《化学科学与工程前沿(英文)》 2023年 第17卷 第9期   页码 1231-1243 doi: 10.1007/s11705-023-2306-z

摘要: The cycling stability of SnO2 anode as lithium-ion battery is poor due to volume expansion. Polyimide coatings can effectively confine the expansion of SnO2. However, linear polyimides are easily dissolved in ester electrolytes and their carbonyls is not fully utilized during charging/discharging process. Herein, the SnO2 enclosed with anthraquinone-based polyimide/reduced graphene oxide composite was prepared by self-assembly. Carbonyls from the anthraquinone unit provide fully available active sites to react with Li+, improving the utilization of carbonyl in the polyimide. More exposed carbonyl active sites promote the conversion of Sn to SnO2 with electrode gradual activation, leading to an increase in reversible capacity during the charge/discharge cycle. In addition, the introduction of reduced graphene oxide cannot only improve the stability of polyimide in the electrolyte, but also build fast ion and electron transport channels for composite electrodes. Due to the multiple effects of anthraquinone-based polyimide and the synergistic effect of reducing graphene oxide, the composite anode exhibits a maximum reversible capacity of 1266 mAh·g−1 at 0.25 A·g−1, and maintains an excellent specific capacity of 983 mAh·g−1 after 200 cycles. This work provides a new strategy for the synergistic modification of SnO2.

关键词: anthraquinone-based polyimide     multi-effect     tin dioxide     reduced graphene oxide     lithium-ion battery    

有固相析出的多效两段蒸发系统模型与过程模拟

李玲,阮奇

《中国工程科学》 2008年 第10卷 第10期   页码 54-60

摘要:

建立了带有冷凝水闪蒸的有固相析出的多效两段蒸发系统的常规设计数学模型,模型将系统的相平衡关系用回归式表达,使模型可以用计算机编程求解,避免了手工计算结合查相图的烦琐的计算过程;利用矩阵方程具有结构清晰和高度模块化的特点,将系统的物料衡算和热量衡算方程组写成矩阵方程的形式,只要保留或舍弃矩阵方程中的相关块矩阵,模型就能代表没有冷凝水闪蒸或没有固相析出的多效两段蒸发系统常规设计模型;采用迭代法结合矩阵法来求解模型,算例表明,冷凝水闪蒸对多效两段蒸发系统是有效的节能措施,算法收敛速度快、收敛稳定性好。

关键词: 固相析出     多效两段蒸发数学模型     冷凝水闪蒸    

复杂并流多效蒸发系统的数学模型与矩阵解法

阮奇,陈文波,黄诗煌,叶长燊

《中国工程科学》 2001年 第3卷 第4期   页码 36-41

摘要:

建立了有冷凝水闪蒸和额外蒸汽引出的复杂并流多效蒸发系统的数学模型, 常规并流多效蒸发模型只是该模型的一个特例。提出一种新算法--迭代法结合矩阵法求解模型并给出算法框图。算例表明新算法比常用的牛顿迭代法和Broyden法效率更高,具有对初值要求不高、收敛稳定性好、收敛速度快等优点。对三效并流蒸发蔗糖水溶液系统,采用冷凝水闪蒸和引出额外蒸汽将原料液从26.7 ℃预热至90 ℃,约可节省16%的加热生蒸汽,节能效果显著。

关键词: 冷凝水闪蒸     额外蒸汽引出     并流流程     多效蒸发     数学模型     矩阵解法    

Environmental dispersivity in free-water-surface-effect dominated wetland: multi-scale analysis

Zi WU, Zhi LI, Li ZENG, Ling SHAO, Hansong TANG, Qing YANG, Guoqian CHEN

《环境科学与工程前沿(英文)》 2011年 第5卷 第4期   页码 597-603 doi: 10.1007/s11783-011-0311-9

摘要: Distinct from the case with width-dominated shallow wetland flows, the longitudinal evolution of contaminant concentration in the most-typical pattern of wetland as dominated by free-water-surface-effect is characterized by a multi-scale analysis in the present study. An environmental dispersion model for the evolution of the mean concentration is deduced as an extension of Taylor's classical formulation by Mei’s multi-scale analysis. Corresponding environmental dispersivity is found identical to that determined by the method of concentration moments.

关键词: free-surface wetland     environmental dispersion     multi-scale analysis    

An investigation on stress distribution effect on multi- piezoelectric energy harvesters

Hailu YANG, Dongwei CAO

《结构与土木工程前沿(英文)》 2017年 第11卷 第3期   页码 301-307 doi: 10.1007/s11709-017-0404-z

摘要: With the fast development of piezoelectric materials and due to its green and renewable characteristics, the piezoelectric energy harvesting technology has been paid more and more attention by pavement engineers. The stress distribution will significantly affect the piezoelectric material performance. In this paper, the effects of multiple piezoelectric elements on the generation of electrical energy and output power are studied. In the case of constant external load, the number of the piezoelectric units does not necessarily produce more energy. When the same multi piezoelectric units work together, if the stress state of the piezoelectric units is different, the total output energy affected by the connection mode. For uneven stress distribution, the optimal output mode is that each of the piezoelectric units rectified before connected in parallel.

关键词: piezoelectric transducer     uneven stress     impedance matching     optimal energy output    

Effect of steady shear on multi-axial texture of symmetric diblock copolymers

XU Hui, LIU Honglai, HU Ying

《化学科学与工程前沿(英文)》 2007年 第1卷 第1期   页码 26-34 doi: 10.1007/s11705-007-0006-8

摘要: The effect of steady shear on multi-axial texture of symmetric diblock copolymer was investigated by using dynamic density functional theory. Through modifying the periodic boundary condition, the parallel-transverse biaxial texture and perpendicular-parallel-transverse triaxial texture have been observed. In the formation of the multi-axial texture, there are two critical velocities μ and µ, at which the transition between the perpendicular and the parallel lamellar morphology, and the transition between the parallel and the transverse lamellar morphology occur, respectively. The two critical velocities increase as the interaction parameter increases, but they almost remain constant at different shear rates. Furthermore, the rotation from the transverse lamellae to the parallel lamellae induced by the shear strain, and the increase of lamellar spacings of the three lamellae after removing the shear, have also been observed by the time evolution of the morphologies. These phenomena are consistent with experimental work.

Solving multi-objective optimal power flow problem considering wind-STATCOM using differential evolution

Belkacem MAHDAD, K. SRAIRI

《能源前沿(英文)》 2013年 第7卷 第1期   页码 75-89 doi: 10.1007/s11708-012-0222-x

摘要: In this paper, a simple strategy based differential evolution was proposed for solving the problem of multi-objective environmental optimal power flow considering a hybrid model (Wind-Shunt-FACTS). The DE algorithm optimized simultaneously a combined vector control based active power of wind sources and reactive power of multi STATCOM exchanged with the electrical power system to minimize fuel cost and emissions. The proposed strategy was examined and applied to the standard IEEE 30-bus with smooth cost function to solve the problem of security environmental economic dispatch considering multi distributed hybrid model based wind and STATCOM controllers. In addition, the proposed approach was validated on a large practical electrical power system 40 generating units considering valve point effect. Simulation results demonstrate that choosing the installation of multi type of FACTS devices in coordination with many distributed wind sources is a vital research area.

关键词: differential evolution     multi-objective function     optimal power flow     economic dispatch     valve point effect     environment     wind source     STATCOM    

Effect of distributions of fuel concentration and temperature on ignition processes in a diesel PCCI

Yang YU, Wanhua SU,

《能源前沿(英文)》 2010年 第4卷 第2期   页码 269-279 doi: 10.1007/s11708-009-0046-5

摘要: The distributions of fuel concentration and temperature have significant effect on the ignition processes of diesel premixed charge compression ignition (PCCI) combustion. It was found in this study that the ignition process of PCCI combustion organized by multi-pulse injection was strongly influenced by conditions of fuel stratification. The start of low temperature reactions occurred in the leaner area of the combustion chamber in the test engine because the temperature here first reached the point of low temperature reactions. Ignition always occurred in the position where the mixture featured with equivalence ratios close to the mean equivalence ratio of the overall mixture, while the neighboring area of the initial ignition area accumulate heat with a finite speed until finally autoigniting. Moreover, the appearance of highest combustion temperature occurred in the same area at the combustion chamber. For more homogeneous mixture, a higher amount of mixture reached ignition simultaneously, resulting in a larger initial ignition area and a higher temperature at the ignition area. Furthermore, V-type distribution of equivalence ratio was found to be beneficial to retarding high temperature reaction.

关键词: PCCI     fuel stratification     multi-pulse injection     ignition    

弹丸在多层复合介质中的爆炸破坏效应研究

周宁,任辉启,沈兆武,刘瑞朝

《中国工程科学》 2006年 第8卷 第8期   页码 56-60

摘要:

根据实验得到的运动弹丸在多层复合介质中不同深度爆炸时产生的弹坑形状、体积及破坏面积,对破坏效应进行了理论分析,建立了弹丸在多层复合介质中的爆炸破坏分区;考虑主要影响破坏效果因素条件下应用量纲分析方法,并结合实验数据得到了破坏参数与比炸深的无量纲关系式和关系曲线,由这些曲线能够方便地查找所需最佳破坏效果对应的比炸深,在相同条件下,该结果可推广到类似目标的爆炸破坏效应分析。

关键词: 爆炸力学     多层介质     量纲分析     爆炸破坏分区    

Intelligent optimization of renewable resource mixes incorporating the effect of fuel risk, fuel cost

Deepak KUMAR,D. K. MOHANTA,M. Jaya Bharata REDDY

《能源前沿(英文)》 2015年 第9卷 第1期   页码 91-105 doi: 10.1007/s11708-015-0345-y

摘要: Power system planning is a capital intensive investment-decision problem. The majority of the conventional planning conducted since the last half a century has been based on the least cost approach, keeping in view the optimization of cost and reliability of power supply. Recently, renewable energy sources have found a niche in power system planning owing to concerns arising from fast depletion of fossil fuels, fuel price volatility as well as global climatic changes. Thus, power system planning is under-going a paradigm shift to incorporate such recent technologies. This paper assesses the impact of renewable sources using the portfolio theory to incorporate the effects of fuel price volatility as well as CO emissions. An optimization framework using a robust multi-objective evolutionary algorithm, namely NSGA-II, is developed to obtain Pareto optimal solutions. The performance of the proposed approach is assessed and illustrated using the Indian power system considering real-time design practices. The case study for Indian power system validates the efficacy of the proposed methodology as developing countries are also increasing the investment in green energy to increase awareness about clean energy technologies.

关键词: modern portfolio theory     energy policy     CO2 emissions     multi-objective optimization     planning commission    

Optimal placement of wind turbines within a wind farm considering multi-directional wind speed using

A.S.O. OGUNJUYIGBE, T.R. AYODELE, O.D. BAMGBOJE

《能源前沿(英文)》 2021年 第15卷 第1期   页码 240-255 doi: 10.1007/s11708-018-0514-x

摘要: Most wind turbines within wind farms are set up to face a pre-determined wind direction. However, wind directions are intermittent in nature, leading to less electricity production capacity. This paper proposes an algorithm to solve the wind farm layout optimization problem considering multi-angular (MA) wind direction with the aim of maximizing the total power generated on wind farms and minimizing the cost of installation. A two-stage genetic algorithm (GA) equipped with complementary sampling and uniform crossover is used to evolve a MA layout that will yield optimal output regardless of the wind direction. In the first stage, the optimal wind turbine layouts for 8 different major wind directions were determined while the second stage allows each of the previously determined layouts to compete and inter-breed so as to evolve an optimal MA wind farm layout. The proposed MA wind farm layout is thereafter compared to other layouts whose turbines have focused site specific wind turbine orientation. The results reveal that the proposed wind farm layout improves wind power production capacity with minimum cost of installation compared to the layouts with site specific wind turbine layouts. This paper will find application at the planning stage of wind farm.

关键词: optimal placement     wind turbines     wind direction     genetic algorithm     wake effect    

Effect of a commercial dispersion of multi walled carbon nanotubes on the hydration of an oil well cementing

Ocar Aurelio MENDOZA REALES,William C.PEARL Jr,Maria D. M. PAIVA,CristianeR. MIRANDA,Romildo Dias TOLEDO FILHO

《结构与土木工程前沿(英文)》 2016年 第10卷 第2期   页码 174-179 doi: 10.1007/s11709-015-0324-8

摘要: This work studies the influence of a commercial dispersion of multi wall carbon nanotubes (MWCNT) on the hydration of a class G cement paste, at room and elevated down-hole temperatures. The MWCNT dispersion was produced with a solids concentration of 3.0 % by mass and an anionic surfactant as dispersing agent. Cement pastes with water-to-cement ratio of 0.45 and additions of solid MWCNT by mass of cement up to 0.50 % were studied. Isothermal calorimetry results showed a clear retardation of the hydration of cement caused by the surfactant contained in the MWCNT dispersion. Nevertheless, thermogravimetric evaluations showed that once the hydration reaction resumed, the retardation effect of the surfactant did not have a negative impact on the amount of hydration products precipitated. It was concluded that the commercial MWCNT dispersion presents a good potential to be applied in oil well cement pastes.

关键词: carbon nanotubes     surfactant     retardation     combined water     C-S-H    

全球供应链中残次品返工与多期延迟付款和部分延迟订购整合的协同效应 Article

Waqas Ahmed, Muhammad Moazzam, Biswajit Sarkar, Saif Ur Rehman

《工程(英文)》 2021年 第7卷 第2期   页码 260-271 doi: 10.1016/j.eng.2020.07.022

摘要:

在洲际贸易和经济中,商品是从全球供应商那里购买的。有时,预期批次可能包括一小部分残次品。这些残次品可以在修理后出售给顾客,因而仍具有价值。在附近的维修车间对此类产品进行返工而不是退货,既经济划算又可持续。当缺货数量与残次品数量一致时,返工产品可以从车间返回给买方。同时,供应商也会相应地与采购商采取多期延迟付款的策略。整体利润通过中期融资的回报得到最大程度的提高。本研究的目的是建立一个协同库存模型,通过考虑返工、多期延迟付款政策及库存短缺等因素,以获得最大的利润。该模型的研究结果表明,在库存乐观的情况下,通过监控周期时间和阶段比例,可以提高供应链的库存管理绩效。结果证明,当供应商给予买方的许可期限等于或大于生产周期时,利润较小;反之,则利润较大。本文采用代数方法求解封闭系统的最优解。本研究的数学实验旨在提供管理见解与切实可行的实践。

关键词: 残次品     返工     短缺     多期延迟付款     非衍生方法    

Multi-objective optimization for the multi-mode finance-based project scheduling problem

Sameh Al-SHIHABI, Mohammad AlDURGAM

《工程管理前沿(英文)》 2020年 第7卷 第2期   页码 223-237 doi: 10.1007/s42524-020-0097-1

摘要: The finance-based scheduling problem (FBSP) is about scheduling project activities without exceeding a credit line financing limit. The FBSP is extended to consider different execution modes that result in the multi-mode FBSP (MMFBSP). Unfortunately, researchers have abandoned the development of exact models to solve the FBSP and its extensions. Instead, researchers have heavily relied on the use of heuristics and meta-heuristics, which do not guarantee solution optimality. No exact models are available for contractors who look for optimal solutions to the multi-objective MMFBSP. CPLEX, which is an exact solver, has witnessed a significant decrease in its computation time. Moreover, its current version, CPLEX 12.9, solves multi-objective optimization problems. This study presents a mixed-integer linear programming model for the multi-objective MMFBSP. Using CPLEX 12.9, we discuss several techniques that researchers can use to optimize a multi-objective MMFBSP. We test our model by solving several problems from the literature. We also show how to solve multi-objective optimization problems by using CPLEX 12.9 and how computation time increases as problem size increases. The small increase in computation time compared with possible cost savings make exact models a must for practitioners. Moreover, the linear programming-relaxation of the model, which takes seconds, can provide an excellent lower bound.

关键词: multi-objective optimization     finance-based scheduling     multi-mode project scheduling     mixed-integer linear programming     CPLEX    

标题 作者 时间 类型 操作

Modeling analysis on solar steam generator employed in multi-effect distillation (MED) system

Zhaorui ZHAO, Bao YANG, Ziwen XING

期刊论文

Multi-effect anthraquinone-based polyimide enclosed SnO/reduced graphene oxide composite as high-performance

期刊论文

有固相析出的多效两段蒸发系统模型与过程模拟

李玲,阮奇

期刊论文

复杂并流多效蒸发系统的数学模型与矩阵解法

阮奇,陈文波,黄诗煌,叶长燊

期刊论文

Environmental dispersivity in free-water-surface-effect dominated wetland: multi-scale analysis

Zi WU, Zhi LI, Li ZENG, Ling SHAO, Hansong TANG, Qing YANG, Guoqian CHEN

期刊论文

An investigation on stress distribution effect on multi- piezoelectric energy harvesters

Hailu YANG, Dongwei CAO

期刊论文

Effect of steady shear on multi-axial texture of symmetric diblock copolymers

XU Hui, LIU Honglai, HU Ying

期刊论文

Solving multi-objective optimal power flow problem considering wind-STATCOM using differential evolution

Belkacem MAHDAD, K. SRAIRI

期刊论文

Effect of distributions of fuel concentration and temperature on ignition processes in a diesel PCCI

Yang YU, Wanhua SU,

期刊论文

弹丸在多层复合介质中的爆炸破坏效应研究

周宁,任辉启,沈兆武,刘瑞朝

期刊论文

Intelligent optimization of renewable resource mixes incorporating the effect of fuel risk, fuel cost

Deepak KUMAR,D. K. MOHANTA,M. Jaya Bharata REDDY

期刊论文

Optimal placement of wind turbines within a wind farm considering multi-directional wind speed using

A.S.O. OGUNJUYIGBE, T.R. AYODELE, O.D. BAMGBOJE

期刊论文

Effect of a commercial dispersion of multi walled carbon nanotubes on the hydration of an oil well cementing

Ocar Aurelio MENDOZA REALES,William C.PEARL Jr,Maria D. M. PAIVA,CristianeR. MIRANDA,Romildo Dias TOLEDO FILHO

期刊论文

全球供应链中残次品返工与多期延迟付款和部分延迟订购整合的协同效应

Waqas Ahmed, Muhammad Moazzam, Biswajit Sarkar, Saif Ur Rehman

期刊论文

Multi-objective optimization for the multi-mode finance-based project scheduling problem

Sameh Al-SHIHABI, Mohammad AlDURGAM

期刊论文