室内人体移动过程对热舒适的影响研究

使用计算流体力学(CFD)技术,结合动网格技术和刚体运动学理论,对室内人体移动进行了动态模拟,得到了人体移动过程中不同时刻室内流场分布.分析了移动过程中的平均温度、平均速度、温度和速度不均匀性指标,并预测了有效吹风温度(TEDT)、空气分布特性指标(ADPI)和吹风感的不满意率指标(PD),比较了不同人体移动速度对以上指标的影响.模拟结果表明,人体移动对室内气流分布和热舒适有短期影响,能提高室内风速的扰动,造成吹风感.     

活化磷肥的磷素释放特性、肥效及活化机理研究

 【目的】探讨活化磷肥的磷素动态释放特性、分子结构及活化材料与磷矿粉之间的作用和肥效。【方法】采用连续浸提、红外光谱分析仪、差热热重联用仪和盆栽试验。【结果】连续浸提表明，两种活化磷肥连续6次水溶性磷的累积释放量是磷矿粉的3.29、3.59倍；活化磷肥的红外光谱、差热分析结果表明，活化材料与磷矿粉之间发生化学作用，而且活化磷肥中H2PO4－特征吸收谱加强，并出现新的H2PO4－特征吸收谱，使磷矿粉中的磷向有效状态转变；盆栽试验结果表明，两种活化磷肥的磷肥利用率、玉米生物量显著高于磷矿粉，甚至高于过磷酸钙。【结论】与磷矿粉相比，活化磷肥的水溶性磷含量、生物量和磷肥利用率均显著提高。     

The feasibility of using an industrial sewage sludge produce in Pakistan as agricultural fertilizer used for cultivation of Sorghum bicolor L

Abstract

In the present study we evaluate the feasibility of using untreated industrial sewage sludge by liming before use as a fertilizer, produced in Pakistan. In a pots experiment, limed industrial sewage sludge (LSW) and non-limed sewage sludge (NLSW), were amended with soil separately and grown sorghum. After maturity, the sorghum grains were analysed for total contents of potentially toxic metals (TPTM), As, Cd, Cr, Cu, Ni, Pb and Zn. The proportion of different mobility fractions of each element in LWS and NLSW, a modified BCR sequential extraction procedure (Community Bureau of Reference) and single extractions with mild extractants (deionized water and CaCl₂) were used. In LSW, the availability of most of the elements under study was reduced, probably due to the increased pH of soil, while this was the reverse in the cases of Cd and Cu, their mobility was slightly increased by lime-treated sludge. The sorghum grains grown in LSW have low level As, Cr, Ni, Pb and Zn as compared to grains grown in NLSW, except Cu and Cd, which, however, never exceeded legal limits. Thus the research showed that liming, by augmenting soil alkalinity, allows a safe agricultural use even of industrial sludge, which is environmentally hazardous for its great content of heavy metals.     

石家庄地区地源热泵与太阳能复合空调系统的应用研究

针对我国北方地区地源热泵空调系统普遍存在的热平衡失调问题,设计了一款地源热泵与太阳能复合空气调节系统,并于2010年在石家庄市的老年公寓工程改造中应用。结果表明该系统效果良好,改造后比改造前地埋管换热器初始出水温度提高6℃;最低出水温度提高5℃;地源热泵机组能效比由1.67提高到3.82;冬季运行费用由20元/m2降低至11元/m2;该工程冬季总运行费用由5万元降低至2.75万元。该实例证明该系统结合了地源热泵和太阳能的各自优点,在石家庄地区应用效果明显,并且用于太阳能系统的初投资4.5万元一年后已收回成本,有推广应用的价值。     

Thermal habitat use and juvenile growth of Svalbard Arctic charr: evidence from otolith stable oxygen isotope analyses

Abstract – Stable oxygen isotopes (δ¹⁸O) derived from otoliths were used to estimate mean annual water temperatures experienced by individual Svalbard Arctic charr, Salvelinus alpinus (L.), during their first four growth seasons. The analysed Arctic charr experienced a high variety of temperatures, indicating the use of different thermal habitats. A higher proportion of the juveniles experienced warmer temperatures during their first summer compared with later summers, suggesting the selective use of the shallowest littoral areas of the lake. Although the estimated temperatures were consistent with water temperatures found in High Arctic rivers and lakes during summer, they did not represent the annual variation in air temperature registered over the 20 years of otolith measurement. Furthermore, summer otolith increment width did not correlate with the experienced temperature. However, after the second year, otolith increment width was highly dependent on increment width during the previous summer. This study estimated mean summer water temperatures experienced by individual Arctic charr during the first four growth seasons providing additional evidence that stable oxygen isotope analysis can be used to provide insight into the thermal habitat use by juvenile Arctic charr.     

Dissipation and Adsorption Behavior of the Insecticide Ethiprole on Various Cultivated Soils in China

In this study, the hydrolysis of the insecticide ethiprole in buffered solutions at pH 4.0, 7.0 and 9.0, respectively, and the degradation and adsorption-desorption behaviors of ethiprole in ifve agricultural soil samples from China were investigated. The half-lives under anaerobic conditions were faster than that in the aerobic experiment. Ethiprole was relatively stable under both acidic and neutral conditions while it was readily hydrolyzed under alkaling condition. The sorption of ethiprole on ifve soils was well described by the linear and Freundlich equation and mainly governed by soil organic matter. The exothermic process of ethiprole adsorption can also be well explained by physical adsorption. A weak adsorption capacity was observed in all soils, which could readily lead to leaching problems.     

某供热管道平面应变热应力分析

呼兰河供热项目处于哈尔滨高寒地区,根据保温需要,该工程采用双层钢管结构。为分析该类结构的安全性,本文将该管道简化为平面应变的力学模型,并通过理论计算和有限元模拟,给出了该类管道的应力计算公式。本研究对该类热力管道力学分析和安全评价具有一定的参考价值。     

Effects of NaCl concentration on the thermal conductivity of sand and glass beads with moisture contents at levels below field capacity

Abstract

Soil thermal conductivity is a key factor governing its thermal regime. In the present study, we measured the thermal conductivity of Toyoura sand and glass beads using a heat probe method to clarify the effects of gravimetric water content (w) and NaCl concentration (C) and to evaluate the estimation effectiveness of four models (Mochizuki, de Vries, Noborio and Kasubuchi). The de Vries and Kasubuchi models predict the effect of w on soil thermal conductivity, whereas the Noborio model describes the effects of solute concentration and the Mochizuki model describes both parameters. With or without NaCl, the thermal conductivity of both samples increased with increasing w, and the increase could be grouped into three ranges based on w. The upper and lower limits of each water content range were constant, even at varying NaCl concentrations, but the width of the range differed among the three ranges and between the sand and glass bead samples. Although soil thermal conductivity has previously been reported to generally decrease with increasing C, the thermal conductivities of some glass beads increased in the present study, particularly at moisture contents close to field capacity. The change in thermal conductivity as a function of C was linear in all cases. This trend was similar to that of a non-swelling clay in a previous study. The Mochizuki model, which regressed measured thermal conductivity on C and w, predicted the thermal conductivity of sand as well as previous models, but the calculations were easier and the method offers more flexibility for soils with different textures.     

一种新型重载汽车制动鼓

作为汽车制动系统中的关键部件,制动鼓的机械性能备受关注。为了提高制动鼓的强度与散热能力,提出了一种适用于重载汽车的新型制动鼓结构。在ANSYS平台上进行了新型制动鼓的强度评估;联合STARCCM+与ANSYS软件,利用热结构耦合分析衡量了新型制动鼓的强度与散热的综合性能。通过与传统制动鼓的性能对比,表明了新型制动鼓的强度与散热能力有所提升。     

The Effect of Temperature on Growth,Development and Nitrogen in Shoots and Roots in Timothy (Phleum pratense L.), Tested in Growth Chambers

Abstract

The effect of temperature on growth, development and crude protein content of timothy (Phleum pratense L.) was investigated. Plants were grown in pots outdoors and placed in four growth chambers at different mean temperatures (8, 12, 16 and 20°C) and at three different phenological stages in order to study the interaction between temperature, development and growth. They were then harvested at weekly intervals for up to six weeks. Pots left outdoors were harvested at the same time. The dry matter yield of shoots and roots, number of tillers per plant, plant height and crude protein content in shoots and roots were recorded.