Prediction of the thermal conductivity of polar pure liquids

Abstract

A relatively simple technique for the prediction of the thermal conductivity of polar organic fluids over the temperature range from 0° to 100°C is presented. The proposed model is basically derived via the generalized property correlation model developed by Riazi and Daubert in 1980. The method requires, as input, only normal boiling point, specific gravities and dipole moments or acentric factors for each compound of interest. Predicted thermal conductivities are compared with 93 literature data for 12 polar liquids. Average deviation between prediction and experiment is approximately within 8–12%, depending on the type of third input parameter, as opposed to 17% for the much involved method of Robins and Kingrea previously recommended.     

储罐区防火堤排污水阀关闭不严属重大安全隐患

对在安全检查中发现储罐区防火堤排污阀关闭不严的情况,从理论及防火堤、排污阀的作用和隐患可能导致的严重后果进行综合分析,认为此种情况应属于重大安全隐患,并列举了防火堤管理方面存在的若干个类似问题,以引起大家的重视。     

季节性冻土深基坑支护技术研究

通过对中国地质大学(北京)综合游泳馆工程拟建场地土层的土质、深度及基坑深度的分析与比较,确定出基坑深度范围内土层的土质。介绍了季节性冻土深基坑支护经常出现的问题,并分析了这些问题出现的原因。对常用土钉支护方法在季节性冻土深基坑支护中运用的局限性做了总结,最后提出一种改进的土钉支护方法。该法针对冻土发生冻融循环时冻胀与融沉的特点采取了相应的控制措施,从而保证了季节性冻土深基坑的稳定性。该法操作简单可行,实践证明效果明显。     

Growth of Ω Plates and Its Effect on Mechanical Properties in Al-Cu-Mg-Ag Alloy with High Content of Silver

In this study, the effects of thermal exposure at 200 °C on the mechanical properties and the growth of Ω plates in an Al-Cu-Mg-Ag alloy with high content of silver were investigated. It was shown that the tensile strength of the exposed alloy decreased with the increase of the mean lengths of Ω precipitates and the decrease in the volume fraction of the Ω phase. The decrease in tensile strength of the 165 °C/14-h-aged samples was less significant than that of 165 °C/2-h-aged samples because the lengthening rate of Ω plates was lower and the number density of Ω precipitates was higher in the 165 °C/14 h-aged samples. The thickening rate of Ω plates was very low during exposure at 200 °C because of high content of silver, and the growth behavior was caused mainly by the lengthening of Ω plates within the habit plane. High content of silver inhibited the thickening of Ω plates and promoted the lengthening of Ω precipitates during exposure.     

Hydrodynamic effects on erosion-enhanced corrosion of stainless steel in aqueous slurries

This paper studies the hydrodynamic effects of erosive slurry on corrosion of passive target (type 304 stainless steel). The transient current response to disruption of passive film is investigated using the single particle impingement technique. The transient current density over the damaged surface is approximately independent of the hydrodynamics of fluid when the flowing velocity is in range of 5-10 m/s. It is characterized by a sharp rise caused by disruption of passive film and a slow decay due to repassivation. Therefore, the difference in transient current response is a result of different damaged surface area produced by solid particle impingement. After the kinetic parameters of repassivation are determined, the hydrodynamic effects on average corrosion rates of the passive target are quantitatively predictable with aid of the physical model developed by Lu and Luo.     

北京亦庄线商用通信无线覆盖技术

介绍了使用移动通信运营网络在地下空间进行无线通信的技术。利用无线传播技术完成地铁组网方案,将地面商用移动信号引入北京地铁亦庄线地下空间,以满足移动运营商公共无线信号在地铁内的延伸和覆盖,为乘客、工作人员提供高质量的公用移动通信的服务。     

Study of the visible light curing of vinyl ester resins using in situ Raman spectroscopy

In-situ Raman spectroscopy was used for providing the direct measurement of the C = C molar concentration of typical visible light curing vinyl ester resin. Using cyclohexyl ring stretching mode at 748 cm^-1 as reference, the back scattering configuration relative Raman cross section for epoxy vinyl ester resin of vinyl ester resins C = C stretching mode at 1,630 cm^-1 and aromatic ring stretching mode at 1,602 cm^-1 were obtained. The molar concentration of C = C during the curing process was monitored under three different powers. It was found that with the laser power increasing, the molar concentration change rising with time steadily, and visible light curing rate gradually speeding up. The residue C = C molar concentration after long curing process was quantified. This value may be useful for future design of visible light curing resins.     

Sensor Network Localization,Euclidean Distance Matrix completions,and graph realization

We study Semidefinite Programming, SDP, relaxations for Sensor Network Localization, SNL, with anchors and with noisy distance information. The main point of the paper is to view SNL as a (nearest) Euclidean Distance Matrix, EDM, completion problem that does not distinguish between the anchors and the sensors. We show that there are advantages for using the well studied EDM model. In fact, the set of anchors simply corresponds to a given fixed clique for the graph of the EDM problem.