Soot particle sizing during high-pressure Diesel spray combustion via time-resolved laser-induced incandescence

Single-pulse time-resolved laser-induced incandescence (TiRe-LII) signal transients from soot particulates were acquired during unsteady high pressure Diesel combustion in a constant volume cell for typical top dead center conditions during a Diesel engine cycle. Measurements were performed for initial gas pressures between 1 and 3 MPa, injection pressures between 50 and 130 MPa and laser probe timings between 5 and 16 ms after start of fuel injection. In separate experiments and for the same cell operating conditions gas temperatures were deduced from spectrally resolved soot pyrometry measurements. Implementing the LII model of Kock et al. [Combust. Flame 147 (2006) 79-92] ensemble mean soot particle diameters were evaluated from least-squares fitting of theoretical cooling curves to experimental TiRe-LII signal transients. Since in the experiments the environmental gas temperature and the width of an assumed particle size distribution were not known, the effects of the initial choice of these parameters on retrieved particle diameters were investigated. It is shown that evaluated mean particle diameters are only slightly biased by the choice of typical size distribution widths and gas temperatures. For a fixed combustion phase mean particle diameters are not much affected by gas pressure, however they become smaller at high fuel injection pressure. At a mean chamber pressure of 1.39 MPa evaluated mean particle diameters increased by a factor of two for probe delays between 5 and 16 ms after start of injection irrespective of the choices of first-guess fitting variables, indicating a certain robustness of data analysis procedure.     

Capacitated lot sizing by using multi-chromosome crossover strategy

The capacitated lot sizing problem (CLSP) arises when, under capacity constraints, the decision maker has to determine the production schedule and lot sizes that will minimize the total costs involved. The costs considered in this article are order, inventory carrying, and labor costs. The fitness function for the chromosome is computed using these cost elements. Next, the chromosomes are partitioned into good and poor segments based on the individual product chromosomes. This information is later used during crossover operation and results in crossover among multiple chromosomes. Product chromosomes are grouped into three groups, group 1 (top X%), group 2 (next Y%), and group 3 (last Z%). Product chromosomes from Groups 1, 2 and 3 can only form pairs with chromosomes from group 1. Besides, different crossover and mutation probabilities are applied for each group. The results of the experimentation showed that the different strategies of the proposed approach produced much better results than the classical genetic algorithm. This article has been submitted to the Journal of Intelligent Manufacturing for publication.     

热连轧工艺中定宽压力机的性能特点

结合鞍钢新建１７８０ｍｍ热连轧带钢机组，介绍了当代热连轧带钢机组的最新设备之一－定宽压力机组的组成、作用儿技术特征。通过具体实例，论证了定宽压力机的设置，不仅提高了钢材的收得率，而且大大减少了板坯连铸机的浇铸宽度规格，从而提高了板坯连铸机的生产能力。     

三辊定径机的工艺探讨

定径是无缝钢管生产的重要工序，其孔型设计和管端壁厚控制是两个影响成品质量的重要工艺问题。在生产实践的基础上，提出了三辊定径机的工艺设计原则，依据钢管壁厚，确定孔型的设计参数；依据钢管的规格系数确定管端增厚的长度，从而确保了无缝钢管的外径精度和管端的壁厚精度。     

A sizing method for stand-alone PV installations with variable demand

The practical applicability of the considerations made in a previous paper to characterize energy balances in stand-alone photovoltaic systems (SAPV) is presented. Given that energy balances were characterized based on monthly estimations, the method is appropriate for sizing installations with variable monthly demands and variable monthly panel tilt (for seasonal estimations).The method presented is original in that it is the only method proposed for this type of demand. The method is based on the rational utilization of daily solar radiation distribution functions. When exact mathematical expressions are not available, approximate empirical expressions can be used. The more precise the statistical characterization of the solar radiation on the receiver module, the more precise the sizing method given that the characterization will solely depend on the distribution function of the daily global irradiation on the tilted surface H_gβi.This method, like previous ones, uses the concept of loss of load probability (LLP) as a parameter to characterize system design and includes information on the standard deviation of this parameter (σ_LLP) as well as two new parameters: annual number of system failures (f) and the standard deviation of annual number of system failures (σ_f).This paper therefore provides an analytical method for evaluating and sizing stand-alone PV systems with variable monthly demand and panel inclination. The sizing method has also been applied in a practical manner.     

矿山碎磨设备选型的主要试验方法

不同的碎磨设备,所适应的矿石粒度区间不同,有不同的选型试验方法。针对不同的碎磨设备选型,介绍了目前国际上常见的主要试验方法。同时,某些碎磨设备有多种试验选型方法,在不同的试验方法之间,有些通过研究建立了相关性,有些没有建立相关性,但不同试验相互之间不可轻易取代。     

浸润剂对短切玻纤增强尼龙66性能影响的研究

利用双螺杆挤出机制备短玻纤增强尼龙66（GF／PA66）复合材料,采用不同组成的浸润剂处理玻璃纤维,研究其对GF／PA66的微观结构及性能的影响。结果表明,在T435D中加入乙烯基树脂或三聚氰胺后,玻纤增强尼龙66复合材料的拉伸强度、弯曲强度、简支梁冲击强度均有不同程度的提高,并通过扫描电镜观察到PA66基体与玻纤相界面的微观结构在一定程度上得到了改善,但在T435D中加入三聚氰胺在三种浸润剂配方中效果最佳。     

纸厂回收淀粉用于纸张施胶剂的制备与应用

以纸厂回收并经过处理的废淀粉作为聚合物的主链,通过接枝苯乙烯(St)、丙烯酸丁酯(BA)及甲基丙烯酸甲酯(MMA)等单体,合成出一种稳定的苯丙乳液施胶剂。结果表明:当w(引发剂)=2.5%~4%、反应温度为70~80℃和m(总单体)∶m(废淀粉)=1∶1.5时,废淀粉接枝共聚物乳液施胶剂的综合性能最好;该施胶剂能有效提高原纸张的各项性能,在同等条件下其性能略低于市售施胶剂;废淀粉回收价格较低,将其用于纸张施胶剂的制备,可达到降低污染、节约成本等目的。     

Influence of raised floor on zone design cooling load in commercial buildings

The installation of a raised floor system can change the thermal behaviour of the building by reducing the interaction between the heat gains and the thermally massive concrete slab. In this study, the influence of the raised floor on the summer design day zone cooling load profile is evaluated with EnergyPlus for an office building located in San Francisco. The effects of structure type, window-to-wall ratio and the presence of carpet on the thermal behaviour of the raised floor are also investigated. The results show that the mere presence of the raised floor largely affects the zone cooling load profile and the peak cooling load over the range of −7 to +40%. The most significant parameters are the zone orientation, i.e. the exposure to direct solar radiation, and the presence of floor carpeting. If carpeting is present, commonly used in U.S. office buildings, the overall impact on zone peak cooling load is reduced, ranging from 0 to 5% greater for the raised floor than without it. Without carpet the peak cooling load is 4% greater with raised floor than without it in the north zone, 22% in the east and west zones, and 12% in the south zone.