资源类型

期刊论文 184

会议视频 1

年份

2024 1

2023 6

2022 10

2021 17

2020 11

2019 15

2018 12

2017 8

2016 22

2015 10

2014 18

2013 6

2012 11

2011 7

2010 6

2009 6

2008 5

2007 2

2006 1

2005 1

展开 ︾

关键词

增材制造 2

生物传感器 2

2R-1C模型;嵌入式系统;参数估计;非迭代方法;二次型 1

3D生物打印 1

ANP 1

COVID-19 1

Chord图 1

Klee图 1

Mittag-Leffler稳定性;分数阶;四元数神经网络;脉冲 1

R&D人力资本投资风险 1

R/S分析 1

Skyline图 1

W-M分形模型 1

[BMIm]PF6 1

[C6MIm]PF6 1

[PMIm]PF6 1

mcr 1

“trade-off”效应 1

中国铅基反应堆 1

展开 ︾

检索范围:

排序: 展示方式:

Experimental study on saturated flow boiling heat transfer of R290/R152a binary mixtures in a horizontal

Xin ZOU, Maoqiong GONG, Gaofei CHEN, Zhaohu SUN, Jianfeng WU

《能源前沿(英文)》 2010年 第4卷 第4期   页码 527-534 doi: 10.1007/s11708-010-0109-7

摘要: An experimental study on the saturated flow boiling heat transfer for a binary mixture of R290/R152a at various compositions is conducted at pressures ranging from 0.2 to 0.4 MPa. The heat transfer coefficients are experimentally measured over mass fluxes ranging from 74.1 to 146.5 kg/(m ·s) and heat fluxes ranging from 13.1 to 65.5 kW/m . The influences of different parameters such as quality, saturation pressure, heat flux, and mass flux on the local heat transfer coefficient are discussed. Existing correlations are analyzed. The Gungor-Winterton correlation shows the best fit among experimental data for the two pure refrigerants. A modified correlation for the binary mixture is proposed based on the authors’ previous work on pool boiling heat transfer and the database obtained from this study. The result shows that the total mean deviation is 10.41% for R290/R152a mixtures, with 97.6% of the predictions falling within±30%.

关键词: flow boiling     heat transfer     binary mixture     R290/R152a    

ZnO nanorefrigerant in R152a refrigeration system for energy conservation and green environment

SENDIL KUMAR,R. ELANSEZHIAN

《机械工程前沿(英文)》 2014年 第9卷 第1期   页码 75-80 doi: 10.1007/s11465-014-0285-y

摘要:

In this paper the reliability and performance of a vapour compression refrigeration system with ZnO nanoparticles in the working fluid was investigated experimentally. Nanorefrigerant was synthesized on the basis of the concept of the nanofluids, which was prepared by mixing ZnO nanoparticles with R152a refrigerant. The conventional refrigerant R134a has a global warming potential (GWP) of 1300 whereas R152a has a significant reduced value of GWP of 140 only. An experimental test rig is designed and fabricated indigenously in the laboratory to carry out the investigations. ZnO nanoparticles with refrigerant mixture were used in HFC R152a refrigeration system. The system performance with nanoparticles was then investigated. The concentration of nano ZnO ranges in the order of 0.1% v, 0.3% v and 0.5%v with particle size of 50 nm and 150 g of R152a was charged and tests were conducted. The compressor suction pressure, discharge pressure and evaporator temperature were measured. The results indicated that ZnO nanorefrigerant works normally and safely in the system. The ZnO nanoparticle concentration is an important factor considered for heat transfer enhancement in the refrigeration system. The performance of the system was significantly improved with 21% less energy consumption when 0.5%v ZnO-R152a refrigerant. Both the suction pressure and discharge pressure were lowered by 10.5% when nanorefrigerant was used. The evaporator temperature was reduced by 6% with the use of nanorefrigerant. Hence ZnO nanoparticles could be used in refrigeration system to considerably reduce energy consumption. The usage of R152a with zero ozone depleting potential (ODP) and very less GWP and thus provides a green and clean environment. The complete experimental results and their analysis are reported in the main paper.

关键词: ZnO nanorefrigerant     reduced GWP     COP     pressure ratio green energy    

Optimization of cellulase production using

Saravanan P, Muthuvelayudham R, Rajesh Kannan R, Viruthagiri T

《化学科学与工程前沿(英文)》 2012年 第6卷 第4期   页码 443-452 doi: 10.1007/s11705-012-1225-1

摘要: The potential of for cellulase production using pineapple waste as substrate has been investigated. A maximum cellulase activity of 9.23 U/mL is obtained under the optimum experimental conditions: pH (5.5), temperature (37.5°C), initial substrate concentration (3%), inoculum concentration (6.6 × 10 ?CFU/mL), and culture time (6 days). Box-Behnken design (BBD) statistical tool and genetic algorithm (GA) are used to optimize the process parameters. The BBD study of linear and quadratic interactive effects of experimental variables on the desired response of cellulase activity showed that the second order polynomial is significant ( = 0.9414). The experimental cellulase activity under the optimal conditions identified by the BBD is 9.23 U/mL and that by GA is 6.98 U/mL. This result indicates that the BBD model gives better result than GA in the present case.

关键词: cellulase     pineapple waste     Trichoderma reesei     Box-Behnken design     genetic algorithm    

Opinion: Agriculture Green Development

John R. PORTER

《农业科学与工程前沿(英文)》 2020年 第7卷 第1期   页码 117-119 doi: 10.15302/J-FASE-2019315

Design concepts of an aircraft wing: composite and morphing airfoil with auxetic structures

P R BUDARAPU,Sudhir Sastry Y B,R NATARAJAN

《结构与土木工程前沿(英文)》 2016年 第10卷 第4期   页码 394-408 doi: 10.1007/s11709-016-0352-z

摘要: This paper is categorized into two parts. (1) A frame work to design the aircraft wing structure and (2) analysis of a morphing airfoil with auxetic structure. The developed design frame work in the first part is used to arrive at the sizes of the various components of an aircraft wing structure. The strength based design is adopted, where the design loads are extracted from the aerodynamic loads. The aerodynamic loads acting on a wing structure are converted to equivalent distributed loads, which are further converted point loads to arrive at the shear forces, bending and twisting moments along the wing span. Based on the estimated shear forces, bending and twisting moments, the strength based design is employed to estimate the sizes of various sections of a composite wing structure. A three dimensional numerical model of the composite wing structure has been developed and analyzed for the extreme load conditions. Glass fiber reinforced plastic material is used in the numerical analysis. The estimated natural frequencies are observed to be in the acceptable limits. Furthermore, the discussed design principles in the first part are extended to the design of a morphing airfoil with auxetic structure. The advantages of the morphing airfoil with auxetic structure are (i) larger displacement with limited straining of the components and (ii) unique deformation characteristics, which produce a theoretical in-plane Poisson’s ratio of −1. Aluminum Alloy AL6061-T651 is considered in the design of all the structural elements. The compliance characteristics of the airfoil are investigated through a numerical model. The numerical results are observed to be in close agreement with the experimental results in the literature.

关键词: wing design     aerodynamic loads     morphing airfoil     auxetic structures     negative Poisson’s ratio    

A photolysis coefficient for characterizing the response of aqueous constituents to photolysis

David R. HOKANSON,Ke LI,R. Rhodes TRUSSELL

《环境科学与工程前沿(英文)》 2016年 第10卷 第3期   页码 428-437 doi: 10.1007/s11783-015-0780-3

摘要: UV photolysis and UV based advanced oxidation processes (AOPs) are gaining more and more attention for drinking water treatment. Quantum yield ( ) and molar absorption coefficient ( ) are the two critical parameters measuring the effectiveness of photolysis of a compound. The product of the two was proposed as a fundamental measure of a constituent’s amenability to transformation by photolysis. It was shown that this product, named the photolysis coefficient, , can be determined using standard bench tests and captures the properties that govern a constituent’s transformation when exposed to light. The development showed the photolysis coefficient to be equally useful for microbiological, inorganic and organic constituents. Values of calculated by the authors based on quantum yield and molar absorption coefficient data from the literature were summarized. Photolysis coefficients among microorganisms ranged from 8500 to more than 600000 and are far higher than for inorganic and organic compounds, which varied over a range of approximately 10 to 1000 and are much less sensitive to UV photolysis than the microorganisms.

关键词: UV photolysis     disinfection     advanced oxidation     N-nitrosodimethylamine     quantum yield     absorption coefficient    

动物营养和饲料科学

Adrian R. Egan

《工程(英文)》 2017年 第3卷 第5期   页码 586-587 doi: 10.1016/J.ENG.2017.05.025

Exergy analysis of R1234ze(Z) as high temperature heat pump working fluid with multi-stage compression

WANG, R.Z. WANG

《能源前沿(英文)》 2017年 第11卷 第4期   页码 493-502 doi: 10.1007/s11708-017-0510-6

摘要: In this paper, the simulation approach and exergy analysis of multi-stage compression high temperature heat pump (HTHP) systems with R1234ze(Z) working fluid are conducted. Both the single-stage and multi-stage compression cycles are analyzed to compare the system performance with 120°C pressurized hot water supply based upon waste heat recovery. The exergy destruction ratios of each component for different stage compression systems are compared. The results show that the exergy loss ratios of the compressor are bigger than that of the evaporator and the condenser for the single-stage compression system. The multi-stage compression system has better energy and exergy efficiencies with the increase of compression stage number. Compared with the single-stage compression system, the coefficient of performance (COP) improvements of the two-stage and three-stage compression system are 9.1% and 14.6%, respectively. When the waste heat source temperature is 60°C, the exergy efficiencies increase about 6.9% and 11.8% for the two-stage and three-stage compression system respectively.

关键词: multi-stage compression     high temperature heat pump     heat recovery     exergy destruction     R1234ze(Z) working fluid    

Improvement potential of today’s WEEE recycling performance: The case of LCD TVs in Belgium

Paul Vanegas, Jef R. Peeters, Dirk Cattrysse, Wim Dewulf, Joost R. Duflou

《环境科学与工程前沿(英文)》 2017年 第11卷 第5期 doi: 10.1007/s11783-017-1000-0

摘要: Waste of electrical and electronic equipment (WEEE) constitutes one of the most relevant waste streams because of the quantity and presence of valuable materials. However, there is limited knowledge on the resource potential of urban mining WEEE, as data on material composition, and the efficiency of current recycling treatments are still scarce. In this article, an evaluation of the recycling performance at a national level for one of the fastest growing e-waste streams: LCD TVs is carried out through the following four steps. Firstly, material characterisation is performed by means of sampling of the waste stream. Secondly, a material flow analysis is conducted by evaluating the separation performance of a recycling plant in Belgium. Thirdly, the recovered economic value and avoided environmental impact (EI) of the analysed recycling system is assessed. Finally, the potential of urban mining for Belgium is forecasted. The analysis shows that while recycling performance for ferrous metals and aluminium are relatively high; there is substantial room to better close the material loops for precious metals (PM) and plastics. PMs and plastics account for 66 % of the economic value in LCD TVs and 57% of the EI. With the current, commonly applied recycling technology only one-third of the PM and housing plastics are recycled; meaning that for these materials, at a national level for Belgium, there is a potential for improvement that represents 3.3 million euros in 2016 and 6.8 million euros in 2025.

关键词: Recycling     Waste of electrical and electronic equipment (WEEE)     Material flow analysis     LCD TVs     Precious metals     Plastics    

Evaluating R&D efficiency of China’s listed lithium battery enterprises

《工程管理前沿(英文)》   页码 473-485 doi: 10.1007/s42524-022-0213-5

摘要: Promoting the growth of the lithium battery sector has been a critical aspect of China’s energy policy in terms of achieving carbon neutrality. However, despite significant support on research and development (R&D) investments that have resulted in increasing size, the sector seems to be falling behind in technological areas. To guide future policies and understand proper ways of promoting R&D efficiency, we looked into the lithium battery industry of China. Specifically, data envelopment analysis (DEA) was used as the primary approach based on evidence from 22 listed lithium battery enterprises. The performance of the five leading players was compared with that of the industry as a whole. Results revealed little indication of a meaningful improvement in R&D efficiency throughout our sample from 2010 to 2019. However, during this period, a significant increase in R&D expenditure was witnessed. This finding was supported, as the results showed that the average technical efficiency of the 22 enterprises was 0.442, whereas the average pure technical efficiency was at 0.503, thus suggesting that they were suffering from decreasing returns to scale (DRS). In contrast, the performance of the five leading players seemed superior because their average efficiency scores were higher than the industry’s average. Moreover, they were experiencing increasing scale efficiency (IRS). We draw on these findings to suggest to policymakers that supporting technologically intensive sectors should be more than simply increasing investment scale; rather, it should also encompass assisting businesses in developing efficient managerial processes for R&D.

关键词: Data Envelopment Analysis     R&D investment efficiency     China’s listed lithium battery enterprises     technical efficiency     pure technical efficiency     scale efficiency    

Significant progress in solution of nonlinear equations at displacement of structure and heat transfer extended surface by new AGM approach

R. AKBARI,D. D. GANJI,M. NIMAFAR,A. R. AHMADI

《机械工程前沿(英文)》 2014年 第9卷 第4期   页码 390-401 doi: 10.1007/s11465-014-0313-y

摘要:

In this paper, we aim to promote the capability of solving two complicated nonlinear differential equations: 1) Static analysis of the structure with variable cross section areas and materials with slope-deflection method; 2) the problem of one dimensional heat transfer with a logarithmic various surface A(x) and a logarithmic various heat generation G(x) with a simple and innovative approach entitled “Akbari-Ganji’s method” (AGM). Comparisons are made between AGM and numerical method, the results of which reveal that this method is very effective and simple and can be applied for other nonlinear problems. It is significant that there are some valuable advantages in this method and also most of the differential equations sets can be answered in this manner while in other methods there is no guarantee to obtain the good results up to now. Brief excellences of this method compared to other approaches are as follows: 1) Differential equations can be solved directly by this method; 2) without any dimensionless procedure, equation(s) can be solved; 3) it is not necessary to convert variables into new ones. According to the aforementioned assertions which are proved in this case study, the process of solving nonlinear equation(s) is very easy and convenient in comparison to other methods.

关键词: AGM     extended surface     heat transfer     slope-deflection method    

Strategies to reduce nutrient pollution from manure management in China

David R. CHADWICK, John R.

《农业科学与工程前沿(英文)》 2020年 第7卷 第1期   页码 45-55 doi: 10.15302/J-FASE-2019293

摘要:

As the demand for livestock products continues to increase in China, so too does the challenge of managing increasing quantities of manure. Urgent action is needed to control point source (housing, storage and processing) and diffuse (field application) pollution and improve the utilization of manure nutrients and organic matter. Here, we review strategies to improve management at each stage of the manure management chain and at different scales. Many strategies require infrastructure investment, e.g., for containment of all manure fractions. Engineering solutions are needed to develop advanced composting systems with lower environmental footprints and design more efficient nutrient stripping technologies. At the field-scale, there is an urgent need to develop a manure nutrient recommendation system that accounts for the range of manure types, cropping systems, soils and climates throughout China. At the regional scale, coordinated planning is necessary to promote recoupling of livestock and cropping systems, and reduce nutrient accumulation in regions with little available landbank, while minimizing the risk of pollution swapping from one region to another. A range of stakeholders are needed to support the step change and innovation required to improve manure management, reduce reliance on inorganic fertilizers, and generate new business opportunities.

关键词: cropping farms     livestock production     manure management chain     recoupling     nutrient loss    

Optimal dynamic emergency reserve activation using spinning, hydro and demand-side reserves

R. BIJWE,A. R. ABHYANKAR

《能源前沿(英文)》 2016年 第10卷 第4期   页码 409-423 doi: 10.1007/s11708-016-0431-9

摘要: This paper proposes an optimal dynamic reserve activation plan after the occurrence of an emergency situation (generator/transmission line outage, load increase or both). An optimal plan is developed to handle the emergency, using the coordinated action of fast and slow reserves, for secure operation with minimum overall cost. It considers the reserves supplied by the conventional thermal generators (spinning reserves), hydro power units and load demands (demand-side reserves). The optimal backing down of costly/fast reserves and bringing up of slow reserves in each sub-interval in an integrated manner is proposed. The proposed reserve activation approaches are solved using the genetic algorithm, and some of the simulation results are also compared using the Matlab optimization toolbox and the general algebraic modeling system (GAMS) software. The simulation studies are performed on the IEEE 30, 57 and 300 bus test systems. These results demonstrate the advantage of the proposed integrated/dynamic reserve activation plan over the conventional/sequential approach.

关键词: demand-side reserves     dynamic reserve activation approach     hydro power units     post contingency     sequential reserve activation approach     spinning reserves    

细菌耐药性威胁人类健康 Editorial

沈建忠, Timothy R. Walsh

《工程(英文)》 2022年 第15卷 第8期   页码 1-2 doi: 10.1016/j.eng.2022.06.003

Estimation of relations among hysteretic response measures and design parameters for RC rectangular shear walls

R. BANAN, Mo. R. BANAN, S. FARHADI

《结构与土木工程前沿(英文)》 2018年 第12卷 第1期   页码 3-15 doi: 10.1007/s11709-017-0418-6

摘要: Seismic design of RC structures requires estimation of structural member behavioral measures as functions of design parameters. In this study, the relations among cyclic behavioral measures and design parameters have been investigated for rectangular RC shear walls using numerical simulations calibrated based on the published laboratory tests. The OpenSEES numerical simulations modeling of plastic hinge hysteretic behavior of RC shear walls and estimation of empirical relations among wall hysteretic indices and design parameters are presented. The principal design parameters considered were wall dimensions, axial force, reinforcement ratios, and end-element design parameters. The estimated hysteretic response measures are wall effective stiffness, yield and ultimate curvatures, plastic moment capacity, yield and ultimate displacements, flexural shear capacity, and dissipated energy. Using results of numerous analyses, the empirical relations among wall cyclic behavioral measures and design parameters are developed and their accuracy is investigated.

关键词: RC wall hysteretic measures     RC wall design parameters     empirical relations     numerical simulations     RC rectangular wall plastic hinge    

标题 作者 时间 类型 操作

Experimental study on saturated flow boiling heat transfer of R290/R152a binary mixtures in a horizontal

Xin ZOU, Maoqiong GONG, Gaofei CHEN, Zhaohu SUN, Jianfeng WU

期刊论文

ZnO nanorefrigerant in R152a refrigeration system for energy conservation and green environment

SENDIL KUMAR,R. ELANSEZHIAN

期刊论文

Optimization of cellulase production using

Saravanan P, Muthuvelayudham R, Rajesh Kannan R, Viruthagiri T

期刊论文

Opinion: Agriculture Green Development

John R. PORTER

期刊论文

Design concepts of an aircraft wing: composite and morphing airfoil with auxetic structures

P R BUDARAPU,Sudhir Sastry Y B,R NATARAJAN

期刊论文

A photolysis coefficient for characterizing the response of aqueous constituents to photolysis

David R. HOKANSON,Ke LI,R. Rhodes TRUSSELL

期刊论文

动物营养和饲料科学

Adrian R. Egan

期刊论文

Exergy analysis of R1234ze(Z) as high temperature heat pump working fluid with multi-stage compression

WANG, R.Z. WANG

期刊论文

Improvement potential of today’s WEEE recycling performance: The case of LCD TVs in Belgium

Paul Vanegas, Jef R. Peeters, Dirk Cattrysse, Wim Dewulf, Joost R. Duflou

期刊论文

Evaluating R&D efficiency of China’s listed lithium battery enterprises

期刊论文

Significant progress in solution of nonlinear equations at displacement of structure and heat transfer extended surface by new AGM approach

R. AKBARI,D. D. GANJI,M. NIMAFAR,A. R. AHMADI

期刊论文

Strategies to reduce nutrient pollution from manure management in China

David R. CHADWICK, John R.

期刊论文

Optimal dynamic emergency reserve activation using spinning, hydro and demand-side reserves

R. BIJWE,A. R. ABHYANKAR

期刊论文

细菌耐药性威胁人类健康

沈建忠, Timothy R. Walsh

期刊论文

Estimation of relations among hysteretic response measures and design parameters for RC rectangular shear walls

R. BANAN, Mo. R. BANAN, S. FARHADI

期刊论文