建筑结构小节拍均衡流水施工的实践

本文叙述了小节拍均衡流水施工的技术、经济效果;充分利用施工作业面,缩短工期;加快模板周转,大大减少模板投入量;有利于专业化劳动组织,提高操作的熟练程度和工时利用率。     

费改税后公路客运车型选用方法的研究--以山东省公路客运为例

本文以净现值最小为目标函数,提出了旨在确定费改税政策实施后客运车辆选型的βmin(最低实载率)模型和NPVmax (最大净现值) 模型。利用在山东省18家国有道路客运企业588辆中、高档客车的主要技术经济指标调查结果,以费改税政策实施后的公路客运成本为条件,对公路客车投入各类客运路线的技术经济效果进行了初步评价。本研究的结果对于指导公路客运车辆的宏观选型具有一定的指导意义。     

Mechanical behavior of micaceous clays

This study aims to investigate the effect of mica content on the mechanical properties of clays.Commercially available ground mica was blended with a locally available clayey soil,at varying nica contents by mass of 5%,10%,15%,20%,25% and 30%,to artificially prepare various micaceous clay blends.The preliminary testing phase included consistency limits and standard Proctor compaction tests.The primary testing program consisted of unconfined compression(UC),direct shear(DS) and scanning electron microscopy(SEM) tests.The test results showed that the liquid and plastic limits exhibited a linear,monotonically increasing trend with increase in mica content.The rate of increase in the plastic limit,however,was found to be greater than that of the liquid limit,thereby leading to a gradual transition towards a non-plastic,cohesionless character.The soft,spongy fabric and high water demand of the mica mineral led to higher optimum water contents and lower maximum dry unit weights with increasing mica content.Under low confinement conditions,i.e.the UC test and the DS test at low normal stresses,the shear strength was adversely affected by mica.However,the closer packing of the clay and mica components in the matrix under high confinement conditions offsets the adverse effects of mica by inducing frictional resistance at the shearing interface,thus leading to improved strength resistance.     

Predictions of nitrate diffusion in sediment using horizontal attenuated total reflection (HATR) by Fourier transform infrared (FTIR) spectrometry

Using a novel and simple method based on horizontal attenuated total reflection (HATR) by Fourier transform infrared (FTIR) spectrometry, the effective diffusion coefficient, De, of nitrate in a contaminated anthropogenic sediment was estimated as 7.34 x 10(-6)cm2 s(-1). This method, which requires as little as 1 mL of sediment sample, was able to measure the De of a chemical species with a reproducibility of +/-3% in about 5h. Based on this De and a pre-determined nitrate reduction rate, the profiles of nitrate concentration in two sediment columns were satisfactorily predicted from a mathematical model. Results showed that the profile in this aged sediment depended mainly on the diffusion of nitrate and, only to a much lesser degree, the rate of nitrate reduction. Measurements in 55 anthropogenic sediment samples collected from five locations and various depths of a contaminated site further showed that the De of nitrate increased linearly with the water content of the sediment, but decreased with the sediment density. The technique demonstrated in this study shall be applicable for the risk assessment of toxic pollutants in contaminated sediments, and for planning the spatial and time intervals of nitrate injection strategy in bioremediation.     

Speciation of selenium in plant water extracts by ion exchange chromatography-hydride generation atomic absorption spectrometry

Determination of selenium (Se) speciation in plants is important in studying the bioavailability and toxicity of Se in Se-contaminated soil/sediment. In this study, we used an anion exchange resin (Dowex 1-10X) to separate Se into non-amino acid organic Se, Se-amino acids, selenite (Se [IV]) and selenate (Se [VI]) in a plant (Stanleya pinnata) extract. The hydride generation atomic absorption spectrometry (HGAAS) was used to determine concentrations of these Se compounds in plant extracts. Results showed that Se compounds can be quantitatively separated by the resin column. Recovery of five spiked standard Se compounds (trimethylselenonium ion (TMSe+), dimethylselenoxide (DMSeO), selenomethionine (Semet), Se [IV] and Se [VII]) in the plant extract ranged from 92.9 to 103%. Water extractable Se accounted for 60.4-72.6% of the total Se in the plant. Among the soluble Se compounds in the plant extract, Se-amino acids were 73-85.5%, Se [VI] ranged from 7.5 to 19.5% and non-amino acid organic Se was less than 7%. Se [IV] in most samples was below the detection limit (1 microg/g). This study showed that considerable amounts of the accumulated Se [VI] in the plant was metabolized to Se-amino acids during growth of the plant.     

简易自动喷水灭火系统在中小型场所中的应用

通过中小型场所的火灾实体模拟试验,说明了在中小型场所中设置简易自动喷水灭火系统的可行性和重要性。     

建筑科学“三个走向”的发展趋势——走向自然共生、走向公共大众、走向地域文化

本文提出建筑科学大范围内发展趋势的“三个走向”,即走向自然共生、走向公共大众、走向地域文化,并以新世纪的新建筑实例说明这“三个走向”的发展趋势,这也是落实可持续发展战略的中心内容。     

北京远南大厦设计及其成败得失

介绍了北京南大厦供暖，空调通风，机械排风以及防排烟系统的设计概况，总结了设计中的成功经验，并结合运行情况，提出了一些在设计，生产，施工安装中应注意的问题。     

The creation of the incapable social tenant in Flanders,Belgium. An appraisal

As long as the social rented sector housed traditional families and the allocation procedures were rather loose, there was little commotion about the sector. A combination of a change in family structures, economic changes, and the strengthening of allocation procedures in favour of those most in need did change perceptions. Marginalisation and ghettoisation, especially of high-rise social housing estates, became buzzwords. This paper deals with the causes of these changes and with their implications. The marginalisation discourse calls for enlarging the target groups and estate-specific allocation procedures (to obtain a `social mix'). It illustrates a profound desire to diminish the number of ethnic minorities, single parents, single-person households and all kinds of people with a weak income profile who gain access to social rental housing. Furthermore, this discourse is reaching a crescendo: after it was started in the early 1990s by staff members of local social housing companies, it passed through the union of the social housing companies, the umbrella organisation of the sector, and parliament, reaching its greatest momentum so far in early 2002 when it was adopted by the Flemish housing minister. The counterpoint to this negative discourse is the high degree of satisfaction among social tenants, as observed in a study carried out in 1999. In our paper we will try to explain the background of these opposing trends and the possible consequences for the social rental housing in general and for tenants in particular.     

Effects of Air Inlet Configuration on Forced-Ventilation Enclosure Fires on a Naval Ship

The effects of air inlet configuration on pool fire behavior in a mechanically ventilated cabin were investigated. The closed cabin used was a model of a certain machinery cabin on a naval ship. Two air inlet configurations of one vent and two vents were taken into account together with five different elevations of air inlet. In one-vent cases, mass loss rate and gas temperature were lower and oxygen concentrations were higher than those of two-vent cases. With the increase of air inlet elevation, a sudden drop in average mass loss rate and peak temperature were found in the two-vent cases at the air inlet elevation of 1.56 m. In one-vent cases, a similar drop in average mass loss rate was found at the air inlet elevation of 0.88 m, while the peak temperature was almost unaffected by inlet elevation. According to temperature profiles and the characteristic parameter of the smoke layer stability, the formation of the smoke layer was destroyed by increasing the air inlet elevation or reducing the air inlets, and furthermore a more uniform distribution could be found. For the current cabin, the one-vent case with a lower air inlet elevation was recommended for smoke control, and the inlet should be set away from the essential equipment and the entrances of the cabin.