Bicriteria scheduling of a material handling robot in an m-machine cell to minimize the energy consumption of the robot and the cycle time

This study considers a flowshop type production system consisting of m machines. A material handling robot transports the parts between the machines and loads and unloads the machines. We consider the sequencing of the robot moves and determining the speeds of these moves simultaneously. These decisions affect both the robot’s energy consumption and the production speed of the system. In this study, these two objectives are considered simultaneously. We propose a second order cone programming formulation to find Pareto efficient solutions. We also develop a heuristic algorithm that finds a set of approximate Pareto efficient solutions. The conic formulation can find robot schedules for small cells with less number of machines in reasonable computation times. Our heuristic algorithm can generate a large set of approximate Pareto efficient solutions in a very short computational time. Proposed solution approaches help the decision-maker to achieve the best trade-off between the throughput of a cell and the energy efficiency of a material handling robot.     

太阳辐照绝对辐射计的精密温度控制系统设计

为了提高太阳辐照绝对辐射计(SIARs)的测量精度,消除温度变化对SIARs测量精度的影响,研究设计了精密温度控制系统,对SIARs进行恒温控制;通过对铂电阻温度传感器自热效应的弱化,提高了温度测量的精度;提出了一种新的复合PID控制算法,该复合控制算法使系统获得良好的动态和稳态性能;使用密闭的高低温箱来模拟星上温度条件对系统进行了实验测试,实验数据表明,系统控制精度在0.1℃以内,可为SIARs工作提供稳定的温度环境。     

太阳能帆板输出功率短期预测研究

在卫星观测中,经常由于各种原因导致短时间内无法提取目标卫星数据,使控制系统无法继续对其保持高精度跟踪和控制。文章主要研究ARIMA模型在卫星遥测数据短期预测中的应用。使用Matlab软件进行ARIMA模型参数计算,再使用SPSS软件执行数据预测,并进行残差分析,通过实例验证,短时期内的预测数据精度较高。     

Fenton试剂处理苯酚和甲醛废水的研究

用H2O2同Fe^2 结合的Fenton试剂处理有机废水是一种经典的催化氧化法，这种方法适合于处理废水中高浓度、难降解的有机物质。主要研究了Fenton试剂处理含苯酚和甲醛有机废水样的反应机理和影响因素，试验结果表明：废水中苯酚和甲醛的去除率均可达到95％以上，COD去除率达到85％以上，表明用Fenton法处理含苯酚和甲醛的有机废水是一种非常有效的方法。     

Degree of crosslinking and mechanical properties of crosslinked poly(vinyl alcohol) beads for use in solid-phase organic synthesis

The limited swellability in polar media of the commonly used polystyrene/divinylbenzene (PS-DVB) support materials for solid-phase organic synthesis has led to the development of novel, highly swellable hydrophilic gels designed for use in aqueous or polar media. Poly(vinyl alcohol) beads crosslinked with epichlorohydrin (PVA-EP) were prepared by a two-step inverse-suspension polymerization method. While it is known that the morphology of the resulting beads can be controlled by the ratio of EP versus PVA as well as by the pre-crosslinking time, the actual degree of crosslinking of the beads and their mechanical properties remain unknown. It is therefore the purpose of this study to evaluate the actual degree of crosslinking of beads prepared with different quantities of crosslinker in the feed by spectroscopic (Raman, nuclear magnetic resonance) and chemical (functional group loading) methods. The mechanical properties of these swollen PVA-EP beads will be evaluated by single-bead unconfined compression in solvents such as water, N,N-dimethylformamide (DMF), and tetrahydrofuran (THF) and compared to model PS-DVB beads commonly used for solid phase synthesis.     

3种高电流密度离子膜电解槽的性能对比与介绍

目前离子膜电解槽的发展方向为复极、自然循环、高电流密度、低电耗，伍德诺拉公司BM2．7-Ⅲ型槽、美国西方化学公司ExL^B-65槽、日本氯工程公司BiTAC-858槽即具有这些先进性能。对这3种槽进行了介绍与对比。     

Transformation of β-Ni(OH)2 to NiO nano-sheets via surface nanocrystalline zirconia coating: Shape and size retention

Shape and size of the synthesized NiO nano-sheets were retained during transformation of sheet-like β-Ni(OH)₂ to NiO at elevated temperatures via nano-sized zirconia coating on the surface of β-Ni(OH)₂. The average grain size was 6.42 nm after 600 °C treatment and slightly increased to 10 nm after 1000 °C treatment, showing effective sintering retardation between NiO nano-sheets. The excellent thermal stability revealed potential application at elevated temperatures, especially for high temperature catalysts and solid-state electrochemical devices.     

Performance of floating cum tilted-wick type solar still with the effect of water flowing over the glass cover

A simple transient performance of floating cum tilted-wick type solar still has been presented by incorporating the effects of water flowing over a glass cover, heat capacity of tilted-wick water surface and floating-wick water surface. Explicit expressions for flowing water, glass, tilted-wick water surface and floating-wick water surface temperature and efficiency of the system have been derived. Numerical calculations have been carried out for a typical day in the month of March 2004. The relative standard deviations between the numerical and experimental results of different temperature components of the proposed still have been found. The results indicate that the relative standard deviations between theoretical and experimental results are less than 8% (glass cover), 2% (tiltedwick water surface), 1% (floating-wick water surface) and 2% (flowing water at the lower end of the glass cover) an average for the working hours of the day. Moreover, based on the numerical results, the following conclusions have been drawn: (i) glass cover temperature decreases significantly; (ii) the effect of water flowing over the glass cover has a fascinating effect on the production of distillate output during peak sunny hours; (iii) water flow rate of 1.5 m/s is optimum, and beyond it the efficiency decreases. Experimental investigations have been performed at Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore, India.     

ESTIMATION OF VAPOR PRESSURES OF ORGANIC NITROGEN AND SULFUR COMPOUNDS BY A GROUP-CONTRIBUTION METHOD

The group-contribution method for vapor pressures of hydrocarbons and organic compounds containing nitrogen or sulfur, based on the kinetic theory of fluids, is revised and extended to include new groups containing nitrogen or sulfur. Good representation is obtained for vapor pressure data in the region 1.30-270 kPa. The method may be used to estimate vapor pressures and enthalpies of vaporization for those organic fluids containing nitrogen or sulfur, where no experimental data are available.     

Dufour's gland and its role in secretion of nest cell lining in bees of the genusColletes (Hymenoptera: Colletidae)

The liquid secretion of the Dufour's gland in mated females comprises a mixture of macrocyclic lactones, straight chain mono- and dicarboxylic acids, together with trace amounts of di- and trihydroxy monocarboxylic acids and a series ofn-alkanes. Polymerization of the liquid to form the membranous nest cell lining, which also contains alanine and glutamic acid as major constituents, may be mediated by an enzyme from the thoracic salivary gland and voided via the mouth. The composition and structure of the cell linings are similar to those of Wigglesworth's cuticulin.