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Gushing metal chain

Alexander BELYAEV,Alexander SUKHANOV,Alexander TSVETKOV

《机械工程前沿(英文)》 2016年 第11卷 第1期   页码 95-100 doi: 10.1007/s11465-016-0377-y

摘要:

This article addresses the problem in which a chain falls from a glass from some height. This phenomenon demonstrates a paradoxical rise of the chain over the glass. To explain this effect, an initial hypothesis and an appropriate theory are proposed for calculating the steady fall parameters of the chain. For this purpose, the modified Сayley ’s problem of falling chain given its rise due to the centrifugal force of upward inertia is solved. Results show that the lift caused by an increase in linear density at the part of chain where it is being bent (the upper part) is due to the convergence of the chain balls to one another. The experiments confirm the obtained estimates of the lifting chain.

关键词: chain     fountain     Meshchersky equation     Cayley’s problem    

Distributed governance of Solar Radiation Management geoengineering: A possible solution to SRM’s “free-driver” problem?

Andrew LOCKLEY

《工程管理前沿(英文)》 2019年 第6卷 第4期   页码 551-556 doi: 10.1007/s42524-019-0055-y

摘要: Geoengineering (deliberate climate modification) is a possible way to limit Anthropogenic Global Warming (AGW) (Shepherd, 2009; National Research Council, 2015). Solar Radiation Management geoengineering (SRM) offers relatively inexpensive, rapid temperature control. However, this low cost leads to a risk of controversial unilateral intervention—the “free-driver” problem (Weitzman, 2015). Consequently, this creates a risk of counter-geoengineering (deliberate warming) (Parker et al., 2018), resulting in governance challenges (Svoboda, 2017) akin to an arms race. Free-driver deployment scenarios previously considered include the rogue state, Greenfinger (Bodansky, 2013), or power blocs (Ricke et al., 2013), implying disagreement and conflict. We propose a novel distributed governance model of consensually-constrained unilateralism: Countries’ authority is limited to each state’s fraction of the maximum realistic intervention (e.g., pre-industrial temperature). We suggest a division of authority based on historical emissions (Rocha et al., 2015)—noting alternatives (e.g., population). To aid understanding, we offer an analogue: An over-heated train carriage, with passenger-controlled windows. We subsequently discuss the likely complexities, notably Coasian side-payments. Finally, we suggest further research: Algebraic, bot and human modeling; and observational studies.

关键词: geoengineering     Solar Radiation Management     governance     decentralised    

中国水利建设的成就 问题和展望

潘家铮

《中国工程科学》 2002年 第4卷 第2期   页码 42-51

摘要:

扼要总结了在1949至2000的50年间中国大陆取得的主要水利建设成就,分别从防洪、灌溉、供水、通航和水能利用等方面加以叙述,并反映到水利科学、技术、教育、管理方面的发展。分析了在取得成就的同时所发生的问题与缺点,探讨了近年来出现的一些新矛盾和新问题,主要有江河防洪标准仍然偏低,未形成可靠和完整的防洪体系;洪水位不断抬高,防汛负担与风险不断增加;水资源过度开发与严重浪费,水质广泛污染,水环境不断恶化以及水利工程配套不全,质量不高,管理粗放,经济效益低落等,并认为产生这些情况的主要因素是思想意识的片面和政策上应如何吸取教训,供决策层参考和全国人民思考。

关键词: 中国水利     成就     问题与展望    

Detection of void and metallic inclusion in 2D piezoelectric cantilever beam using impedance measurements

S. SAMANTA, S. S. NANTHAKUMAR, R. K. ANNABATTULA, X. ZHUANG

《结构与土木工程前沿(英文)》 2019年 第13卷 第3期   页码 542-556 doi: 10.1007/s11709-018-0496-0

摘要: The aim of current work is to improve the existing inverse methodology of void-detection based on a target impedance curve, leading to quick-prediction of the parameters of single circular void. In this work, mode-shape dependent shifting phenomenon of peaks of impedance curve with change in void location has been analyzed. A number of initial guesses followed by an iterative optimization algorithm based on univariate method has been used to solve the problem. In each iteration starting from each initial guess, the difference between the computationally obtained impedance curve and the target impedance curve has been reduced. This methodology has been extended to detect single circular metallic inclusion in 2D piezoelectric cantilever beam. A good accuracy level was observed for detection of flaw radius and flaw-location along beam-length, but not the precise location along beam-width.

关键词: piezoelectricity     impedance curve     mode shapes     inverse problem     flaw detection     curve shifting    

Discussion on Problem-Based Engineering Management System

Qiao Xiang

《工程管理前沿(英文)》 2015年 第2卷 第3期   页码 249-260 doi: 10.15302/J-FEM-2015054

摘要: The paper puts forward the idea of problem-based engineering management, expounds its connotation and guiding ideology and moreover, substantially demonstrates its practical significance in the engineering management system for the maintenance of Chinese military aircraft engines.

关键词: problem     engineering management     system    

Airline planning and scheduling: Models and solution methodologies

Lei ZHOU, Zhe LIANG, Chun-An CHOU, Wanpracha Art CHAOVALITWONGSE

《工程管理前沿(英文)》 2020年 第7卷 第1期   页码 1-26 doi: 10.1007/s42524-020-0093-5

摘要: The airline industry is a representative industry with high cost and low profitability. Therefore, airlines should carefully plan their schedules to ensure that overall profit is maximized. We review the literature on airline planning and scheduling and focus on mathematical formulations and solution methodologies. Our research framework is anchored on three major problems in the airline scheduling, namely, fleet assignment, aircraft routing, and crew scheduling. General formulation, widely used solution approaches, and important extensions are presented for each problem and integrated problems. We conclude the review by identifying promising areas for further research.

关键词: airline planning     fleet assignment problem     aircraft routing problem     crew pairing problem     crew rostering problem     crew scheduling problem     integrated planning    

A solution to stochastic unit commitment problem for a wind-thermal system coordination

B. SARAVANAN,Shreya MISHRA,Debrupa NAG

《能源前沿(英文)》 2014年 第8卷 第2期   页码 192-200 doi: 10.1007/s11708-014-0306-x

摘要: Unit commitment (UC) problem is one of the most important decision making problems in power system. In this paper the UC problem is solved by considering it as a real time problem by adding stochasticity in the generation side because of wind-thermal co-ordination system as well as stochasticity in the load side by incorporating the randomness of the load. The most important issue that needs to be addressed is the achievement of an economic unit commitment solution after solving UC as a real time problem. This paper proposes a hybrid approach to solve the stochastic unit commitment problem considering the volatile nature of wind and formulating the UC problem as a chance constrained problem in which the load is met with high probability over the entire time period.

关键词: unit commitment (UC)     randomness     wind generation     univariate     chance constrained    

Solving unit commitment problem using a novel version of harmony search algorithm

Roozbeh MORSALI,Tohid JAFARI,Amirhossein GHODS,Mohammad KARIMI

《能源前沿(英文)》 2014年 第8卷 第3期   页码 297-304 doi: 10.1007/s11708-014-0309-7

摘要: In this context, a novel structure was proposed for improving harmony search (HS) algorithm to solve the unit comment (UC) problem. The HS algorithm obtained optimal solution for defined objective function by improvising, updating and checking operators. In the proposed improved self-adaptive HS (SGHS) algorithm, two important control parameters were adjusted to reach better solution from the simple HS algorithm. The objective function of this study consisted of operation, start-up and shut-down costs. To confirm the effectiveness, the SGHS algorithm was tested on systems with 10, 20, 40 and 60 generating units, and the obtained results were compared with those of the simple HS algorithm and other related works.

关键词: generation scheduling     harmony search (HS) algorithm     intelligent technique     unit commitment    

Transient analysis of thermoelastic contact problem of disk brakes

Ali BELHOCINE, Mostefa BOUCHETARA

《机械工程前沿(英文)》 2013年 第8卷 第2期   页码 150-159 doi: 10.1007/s11465-013-0266-6

摘要:

The main purpose of this study is to analyze the thermomechanical behavior of the dry contact between the brake disk and pads during the braking phase. The simulation strategy is based on computer code ANSYS11. The modeling of transient temperature in the disk is actually used to identify the factor of geometric design of the disk to install the ventilation system in vehicles. The thermal-structural analysis is then used with coupling to determine the deformation established and the Von Mises stresses in the disk, the contact pressure distribution in pads. The results are satisfactory compared to those found in the literature.

关键词: brake disks     heat flux     heat-transfer coefficient     Von Mises stress     contact pressure    

A solution to the unit commitment problem—a review

B. SARAVANAN, Siddharth DAS, Surbhi SIKRI, D. P. KOTHARI

《能源前沿(英文)》 2013年 第7卷 第2期   页码 223-236 doi: 10.1007/s11708-013-0240-3

摘要: Unit commitment (UC) is an optimization problem used to determine the operation schedule of the generating units at every hour interval with varying loads under different constraints and environments. Many algorithms have been invented in the past five decades for optimization of the UC problem, but still researchers are working in this field to find new hybrid algorithms to make the problem more realistic. The importance of UC is increasing with the constantly varying demands. Therefore, there is an urgent need in the power sector to keep track of the latest methodologies to further optimize the working criterions of the generating units. This paper focuses on providing a clear review of the latest techniques employed in optimizing UC problems for both stochastic and deterministic loads, which has been acquired from many peer reviewed published papers. It has been divided into many sections which include various constraints based on profit, security, emission and time. It emphasizes not only on deregulated and regulated environments but also on renewable energy and distributed generating systems. In terms of contributions, the detailed analysis of all the UC algorithms has been discussed for the benefit of new researchers interested in working in this field.

关键词: unit commitment (UC)     optimization     deterministic load     stochastic load     evolutionary programming (EP)     hybrid    

日本第十次技术预见及其启示

孙胜凯,魏畅,宋超,裴钰

《中国工程科学》 2017年 第19卷 第1期   页码 133-142 doi: 10.15302/J-SSCAE-2017.01.019

摘要:

技术预见作为日本的一项系统性国家科技政策,被长期坚持并卓有成效地开展。目前已开展的十次技术预见活动,对推动日本科技发展部署、企业技术创新与管理能力的提升都发挥了重要作用,并对深入认识技术发展规律具有重要意义。本文系统地介绍了日本第十次技术预见的方法、模式、实施体制及调查流程,分析了其主要经验与问题,为我国开展技术预见活动提供借鉴。

关键词: 日本     技术预见     课题解决型     情景规划     德尔菲调查    

卫星重力梯度数据用于精化地球重力场的研究

宁津生,罗志才,陈永奇

《中国工程科学》 2002年 第4卷 第7期   页码 23-28

摘要:

确定厘米级大地水准面和发展超高阶地球重力场模型是现代物理大地测量的主要科学目标之一。卫星重力梯度测量的实现将为这一目标做出重大贡献。文章着重评述这一领域的研究进展,并讨论利用卫星重力梯度数据精化地球重力场的若干理论和方法问题。

关键词: 卫星重力梯度测量     卫星重力梯度边值问题     地球重力场模型     大地水准面    

Hydrocele of the canal of Nuck — an old problem revisited

null

《医学前沿(英文)》 2013年 第7卷 第4期   页码 517-519 doi: 10.1007/s11684-013-0300-4

摘要:

Herein the authors describe the case of a young woman presenting with a tender lump in her groin. Clinically the differential was of either a reactive lymph node or a femoral hernia. Ultrasound scan was urgently arranged and showed a cystic lesion. Surgical exploration was carried out and revealed this to be a hydrocele of the canal of Nuck. This was excised and the patient’s symptoms resolved and she was discharged home the following day. We explore the embryology, pathophysiology and management of this rare entity.

关键词: canal of Nuck     hernia     embryology    

A solution to unit commitment problem using invasive weed optimization algorithm

B. SARAVANAN, E. R. VASUDEVAN, D. P. KOTHARI

《能源前沿(英文)》 2013年 第7卷 第4期   页码 487-494 doi: 10.1007/s11708-013-0279-1

摘要: Unit commitment (UC) is one of the most important aspect of power generation in the world today. Though, there is no method to find the exact optimized solution, there exists several meta-heuristic algorithms to determine the close to exact solution. This paper proposes a novel solution to effectively determine UC and generation cost using the technique of invasive weed optimization (IWO). The existing technique distributes the load demand among all the generating units. The method proposed here utilizes the output of UC obtained by using the Lagrangian relaxation (LR) method and calculates the required generation from only the plants that are ON discarding the OFF generator units and thereby giving a faster and more accurate response. Moreover, the results show the comparison between the LR-particle swarm optimization (PSO) and LR-IWO, and prove that the cost of generation for a 4 unit, 8 hour schedule is much less in the case of IWO when compared to PSO.

关键词: Lagrangian relaxation (LR)     invasive weed optimization (IWO)     economic dispatch     optimization     fuel cost     seed     fitness    

Method for solving the nonlinear inverse problem in gas face seal diagnosis based on surrogate models

《机械工程前沿(英文)》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0689-z

摘要: Physical models carry quantitative and explainable expert knowledge. However, they have not been introduced into gas face seal diagnosis tasks because of the unacceptable computational cost of inferring the input fault parameters for the observed output or solving the inverse problem of the physical model. The presented work develops a surrogate-model-assisted method for solving the nonlinear inverse problem in limited physical model evaluations. The method prepares a small initial database on sites generated with a Latin hypercube design and then performs an iterative routine that benefits from the rapidity of the surrogate models and the reliability of the physical model. The method is validated on simulated and experimental cases. Results demonstrate that the method can effectively identify the parameters that induce the abnormal signal output with limited physical model evaluations. The presented work provides a quantitative, explainable, and feasible approach for identifying the cause of gas face seal contact. It is also applicable to mechanical devices that face similar difficulties.

关键词: surrogate model     gas face seal     fault diagnosis     nonlinear dynamics     tribology    

标题 作者 时间 类型 操作

Gushing metal chain

Alexander BELYAEV,Alexander SUKHANOV,Alexander TSVETKOV

期刊论文

Distributed governance of Solar Radiation Management geoengineering: A possible solution to SRM’s “free-driver” problem?

Andrew LOCKLEY

期刊论文

中国水利建设的成就 问题和展望

潘家铮

期刊论文

Detection of void and metallic inclusion in 2D piezoelectric cantilever beam using impedance measurements

S. SAMANTA, S. S. NANTHAKUMAR, R. K. ANNABATTULA, X. ZHUANG

期刊论文

Discussion on Problem-Based Engineering Management System

Qiao Xiang

期刊论文

Airline planning and scheduling: Models and solution methodologies

Lei ZHOU, Zhe LIANG, Chun-An CHOU, Wanpracha Art CHAOVALITWONGSE

期刊论文

A solution to stochastic unit commitment problem for a wind-thermal system coordination

B. SARAVANAN,Shreya MISHRA,Debrupa NAG

期刊论文

Solving unit commitment problem using a novel version of harmony search algorithm

Roozbeh MORSALI,Tohid JAFARI,Amirhossein GHODS,Mohammad KARIMI

期刊论文

Transient analysis of thermoelastic contact problem of disk brakes

Ali BELHOCINE, Mostefa BOUCHETARA

期刊论文

A solution to the unit commitment problem—a review

B. SARAVANAN, Siddharth DAS, Surbhi SIKRI, D. P. KOTHARI

期刊论文

日本第十次技术预见及其启示

孙胜凯,魏畅,宋超,裴钰

期刊论文

卫星重力梯度数据用于精化地球重力场的研究

宁津生,罗志才,陈永奇

期刊论文

Hydrocele of the canal of Nuck — an old problem revisited

null

期刊论文

A solution to unit commitment problem using invasive weed optimization algorithm

B. SARAVANAN, E. R. VASUDEVAN, D. P. KOTHARI

期刊论文

Method for solving the nonlinear inverse problem in gas face seal diagnosis based on surrogate models

期刊论文