流域泥沙的资源化及其实现途径

本文以自然资源的概念和属性为基础，研究了流域泥沙的离散性、吸附性、可搬运性等属性，以及水沙不可分性、水沙不协调性、水沙时空分布不均匀性、水沙产生异源等特征。认为流域泥沙具有自然资源的有效性、可控性和稀缺性等属性，指出流域泥沙具有资源性，是一种特殊的自然资源。当流域泥沙在满足技术和社会等一定条件下，是可以资源化的。提出了实现流域泥沙资源化的目标和途径，其途径主要包括填海造陆、改良土壤和引洪淤灌、淤临淤背和作为建筑材料等。     

正确选用热力管网保温材料的几个问题

介绍了做好热力管网保温应具备的有关知识和数据，以及宝钢蒸汽主干管网在采用四种保温材料下的经济保温层厚度和相对的节能效益，认为目前适于宝钢公司热源温度在６００℃以下较好的保温材料有新型矿渣棉制品和泡沫石棉板。     

晋城市煤炭加工利用现状、存在问题及发展建议

阐述了晋城市煤加工利用的现状 ,分析了煤炭加工利用存在的问题 ,提出了今后的发展建议     

位山引黄灌区泥沙淤积原因及处理对策

位山灌区是黄河下游大型引黄灌区 ,渠系泥沙淤积严重 ,泥沙处理困难。通过采用远距离输沙、集中处理沉沙区泥沙、分散沉沙和节水减淤等技术措施 ,减少了渠系的泥沙淤积。对清淤产生的泥沙 ,采取综合开发利用的技术和管理措施 ,取得了比较可靠的效果。     

螺旋槽管强化传热原理及在石化装置上的应用前景

详细介绍了螺旋槽管换热器的强化传热原理 ,阐明了在无相变和有相变两种工况下 ,螺旋槽管换热器的强化作用 ,并介绍了螺旋槽管换热器的设计计算方法。说明了在石油化工装置上应用的必要性     

双跨换热器传热管在静水中阻尼特性的研究

本文对双跨换热器传热管在静水中的结构阻尼与粘滞阻尼作了简介,并对在总阻尼中占主导地位的挤压膜阻尼作了较深入的讨论。Mulcahy 于80年代初提出的挤压膜阻尼数学模型是较为完善的,其缺陷是未计入管子振幅的影响,本文对它进行了修正。为了验证理论分析的结果,笔者对双跨传热管在静水中的挤压膜阻尼作了实验研究,得出挤压膜阻尼与中间支承板厚度、管子-中间支承板间隙以及管子振幅之间的关系。     

论西北地区地下水的开发利用与保护

本文通过分析西北地区的水资源时空分布特点和水循环特点、地下水开发利用现状以及开发利用中出现的生态环境问题，总结了西北地区多年来水资源开发利用的成功经验和失败教训，提出今后地下水资源合理开发利用的几点建议：即提高社会对西北地区地下水的认识，适度增大地下水开采；充分发挥地下水的一态环境调节作用，水资源开发与生态环境保护并举；遵循地表水与地下水的多次相互转化规律，提高水资源总体利用率；水资源开发利用与水资源涵养相结合；加强西北地区地下水的调查与研究。     

The Clausius inequality corrected for heat transfer involving radiation

The objective of this paper is to prove that the Clausius inequality must be re-stated to have general applicability for heat transfer involving radiative fluxes. The integrand (đQ/T) of the Clausius expression applies to heat conduction and convection, but does not hold for most radiative transfer scenarios, with the exception of reversible infinitesimal net blackbody radiation transfer. In other cases involving radiative transfer, the equality holds for a cycle even though irreversible heat addition by radiative transfer occurs. This is without the erroneous presumption of entropy destruction anywhere in the cycle. Thus, the Clausius inequality indicates reversibility for a cycle that includes an irreversible process. Further, in some radiative cases the quantity đQ/T, where T is the boundary temperature, is not the entropy transfer at the system boundary, and in fact, primarily represents entropy production within the system. It is also clear that in another case considered, the quantity đQ/T had no physical meaning whatsoever. Consequently, the Clausius expression has been re-stated so that it is applicable to cycles with processes involving any form of heat transfer. A new integrand (đQ_cc/T + đS_Net,Rad) is presented, allowing the Clausius inequality to generally apply to all heat transfer scenarios. The work in this paper emphasizes the need to re-state other fundamental equations allowing applicability to all heat transfer processes, and draws attention to the unique character of radiative entropy calculations.     

Cooling and Solidification of Melted Drops in an Immiscible Cooling Medium

The cooling and solidification of melted drops during their movement in an immiscible cooling medium is widely employed for granulation in the chemical industry, and a study of these processes to provides a basis for the design of the granulation tower height and the temperature of the cooling medium is reported. A physical model of the cooling and solidification of the drop is established and the numerical calculation is performed. The influences of the key factors in the solidification, i.e., Bi number, drop diameter, temperature of the cooling medium, etc. are presented. The cooling and solidification during wax granulation in a water‐cooling tower and during urea granulation in an air‐cooling tower (spraying tower) are described in detail. Characteristics of the solidification and temperature distribution within the particle at different times are shown. The model and calculations can be used for structure design of the granulation tower and optimization of the operation parameters.     

Thermal-lens and photo-acoustic methods for the determination of SiC thermal properties

In this paper we report the use of photothermal techniques such as Thermal lens (TL) spectrometry, Photoacoustic and heat capacity, ρc_p, to determine the thermo-optical parameters, such as thermal conductivity (K), thermal diffusivity (D), specific heat (c_p) and the optical path dependence with temperature (ds/dT), of an undoped polycrystalline 3C-SiC. To our knowledge, this is the first time that Thermal lens technique is used for wide band-gap systems. Results obtained for the polycrystalline sample with TL technique indicates that ds/dT is negative at room temperature. Moreover, the obtained values of thermal diffusivity and thermal conductivity are in good agreement with that found in the literature, indicating that the phototermal techniques can be used to obtain the referred parameters in circumstances where other techniques cannot be used, for example, in harsh environments.