Investigation of modified horizontal wing cut twisted tapes fitted with rod and spacer at trailing edge on heat transfer properties in Double Glazing V-Trough solar water heaters

An experimental analysis of heat transfer efficiency in double glazing solar water heating system having full-length Horizontal wing cut twisted tapes having twist ratio 3 fitted with rod or spacer of dimensions 125 mm, 250 mm, and 500 mm as length at the trailing edges has been dealt in this work. The experimental results have been compared with a plain tube with similar operating conditions and concluded that variation in the Nusselt number, as well as friction factor, are ±12.56% and ±10.17%, respectively. The result of empirical correlation concludes that Nusselt number is maximal for horizontal wing cut twisted tapes having rod or spacer at its ends while comparing with full-length horizontal wing cut twisted tapes. The friction factor is low for full-length horizontal wing cut twisted tapes than the horizontal wing cut twisted tapes fitted with rod or spacer. The horizontal wing cut twisted tapes fitted with rod has superior performance than twist fitted with spacer.     

N/Ce doped graphene supported Pt nanoparticles for the catalytic oxidation of formaldehyde at room temperature

Pt catalysts with nitrogen-doped graphene oxide (GO) as support and CeO₂ as promoter were prepared by impregnation method,and their catalytic oxidation of formaldehyde (HCHO) at room temperature was tested.The Pt-CeO₂/N-rGO (reduced GO) with a mass fraction of 0.7% Pt and 0.8%CeO₂ exhibited an excellent catalytic performance with the 100% conversion of HCHO at room temperature.Physicochemical characterization demonstrated that nitrogendoping greatly increased the...     

Environmental impact assessment in the association of southeast Asian Nations

The Association of Southeast Asian Nations has agreed that environmental protection and sustainable use of natural resources are essential for sound economic development. The Environmental Impact Assessment is viewed as an important management tool and an ASEAN Experts Group on the Environment has been working for several years on a model especially adapted to the region and also on case studies of the implementation of EIA. Progress so far has been frustratingly slow due to misunderstanding, a lack of ecological data, inadequate trained manpower and institutional shortcomings for compliance. The author advocates collaboration on an ASEAN model for performing EIA as a means of accelerating acceptance and implementation. The concept of Adaptive Environmental Assessment and Management is proposed as a prototype.     

Measurement of selected indoor physical environmental factors in hairdresser salons in a Turkish City

Objectives The purpose of this study was to determine electromagnetic fields, electric fields, humidity, temperature, and illumination levels in hairdresser salons located in the downtown area of Aydin, Turkey. Also some health problems which could be related with the occupational factors are evaluated. Materials and methods The study was carried out in 30 hairdresser salons, all of which had been registered within the past 5 years. Electric and electromagnetic fields, illumination, temperature and humidity measurements were determined for hairdryers, hood hairdryers and depilatory heaters in the participating salons. A brief questionnaire about characteristics and the health status of hairdressers and workplace conditions was prepared and administered to the hairdressers at the salons. Results The mean electric fields of hairdryers, hood hairdryers and depilatory heaters were determined as 518 ± 74, 1,123 ± 199, and 648 ± 146 in V/m, respectively, at 5 cm from the surface of each device. These appliances generate mean electromagnetic fields in excess of 0.25 μT at 5 cm: hand-held hairdryers, 5.0 ± 0.7 μT; hood hairdryers, 1.6 ± 0.3 μT; and depilatory heaters 1.9 ± 0.6 μT. Total average of cumulative electric and electromagnetic fields, measured at a distance of 90 cm from the surface of these three devices was calculated to be 98.8 V/m and 0.5 μT, in the participating salons. Conclusions This preliminary study suggests that physical environmental factors in the salons may be contributing to the health problems of the hairdressers, and the electrical equipments in the workplaces may have cumulative electric and electromagnetic effects.     

太阳能技术在新疆油田的应用研究

以新疆地区太阳能开发优越的自然条件分析为基础,介绍了太阳能发电抽油机技术、供热水的应用,以及太阳能发电供热水的技术原理、系统构成、重要技术参数等。通过实际应用,解析了太阳能利用中最关键的经济效益和节能减排效益两方面的问题,并通过与常规燃煤火力发电技术的对比分析,证明了太阳能发电供热的技术优越性。太阳能发电供热的大规模推广应用,对响应国家节能减排政策,提高油田的节能减排效益和经济效益,创建绿色油气田具有深远的意义。     

汽轮机回热系统安全运行与节能降耗

通过对300 MW汽轮机回热加热系统运行现状调查,分析了加热器端差异常和易发生泄漏原因,并制定了相应的对策。探索了远场涡流检测技术在高压加热器检验中的应用规律,通过高低水位调整试验确定了其最佳运行方式,对高压加热器的设计、制造及运行具有借鉴意义。     

UASB反应器中加入膨润土和聚丙烯酰胺培养颗粒污泥

使用一个反应体积２５５Ｌ的ＵＡＳＢ反应器，处理啤酒生产废水．向接种厌氧污泥中加入膨润土和非离子型聚丙烯酰胺，采用室温下间歇式进料，４周内形成稳定颗粒污泥床．ＣＯＤ负荷６ｋｇ／ｍ３·ｄ，ＣＯＤ去除率为９０％．     

室内空气中微量甲醛污染与监测进展

对近年来国内外有关室内空气中甲醛污染及其监测的一些研究情况进行了简要介绍，并着重对室内空气中甲醛的排放特征和室内空气中甲醛污染研究的方向进行了讨论。     

The siting puzzle: Balancing economic and environmental gains and losses

Traditional approaches to the siting of potentially hazardous but regionally necessary facilities are often ineffective and lead to drawn-out legal disputes ultimately satisfactory to none of the parties. Research at MIT over the last decade has indicated five factors that may solve the siting puzzle. Application of these principles do not guarantee that a decision will not be disputed but may enhance the possibility of a wise and durable agreement.     

室内准稳态压力火灾烟气沉降模型的改进和实验验证

对室内火灾及烟气的研究给消防工程领域带来了诸多益处,如疏散时间预测、基于性能化的设计分析等。Zukoski (Fireand Materials,1978,2(2): 54-62)在室内火灾烟气运动的开创性研究给出了基于质量和能量平衡的理论方法,为后续研究奠定了基础。然而实验发现,由于忽略热损失偏差,模型对近壁面火源的火灾烟气沉降时间的预测缺乏准确度。本文通过空间重构的方法消除房间长宽比因素造成的热损失偏差,引入两个参数进行表征,以完善该模型。完善后的模型预测烟气沉降时间与实验吻合度非常好,验证了该方法的有效性。在计算分析基础上,将两个参数对模型的影响作了评估,发现其一对模型预测结果的影响远大于另一参数。火源大小确定后,烟气充满房间的时间范围可确定,火源功率越大,时间范围越小。