浅析高速公路工程招投标中的最低评标价法

结合目前高速公路施工项目招投标活动的实际情况,阐述了最低评标价法的概念,归纳了其优点及存在问题,对完善最低评标价法提出几点策略,以期促进招标投标市场更加规范有序。     

Pathogens in septage in Vietnam

Septage is widely acknowledged as a major source of infectious pathogens while disposal of septage, and the operation and maintenance of septic tanks, is not regulated in many developing countries. Twenty untreated septage and septage sludge samples were taken from Can Tho City, Vietnam to examine their pathogen content, and indicator micro-organisms. Escherichia coli and Enterococcus spp. were detected in all samples, regardless of sludge storage time. Phages were detected in 80% of samples. Salmonella spp. were detected in 70% of the untreated septage and 60% of septage sludge samples. Concentrations of phages and bacteria tested in septage sludge after many years of tank storage were much higher than the expected levels. Helminth ova were present in 95% of untreated septage samples with an average of 450 ova l^− 1, and were detected in all septage sludge samples with an average of 16,000 ova l^− 1. Twelve varieties of helminth ova were identified. More helminth ova varieties in higher concentrations were found in septage than those reported from stool samples. The varieties' frequency ranged from 10% to 50% and Ascaris lumbricoides predominated. Results show that pathogens and indicator micro-organisms, especially helminth ova, accumulate in sludge. Thus helminth ova should be considered when septage sludge is treated and used for agriculture. Proper health protection measures must be applied for people handling septage.     

Place-Making in Megaprojects in Melbourne

This article analyses state-led place-making practices in Melbourne. The two levels of government that influence planning in Melbourne make much of the city as ‘culturally vibrant’ and ‘creative’, and have incorporated creative city-inspired place-making principles into many layers of the planning system. An examination of the development of two mixed-use megaprojects in central Melbourne reveals however that ideals of culturally engaging public places, and indeed of creative landscapes for middle-class consumption, wither in the face of more basic imperatives for economic development. In these case studies the ‘creative city’, no matter how the idea is interpreted, has little traction either as a set of inclusive place-making principles or as a gentrification strategy. The article concludes that the creative city-inspired place-making objectives in the planning system at both state and local levels are ambiguous in their overall intents and completely unsupported by statutory controls. Such place-making objectives as are realised are the compromised results of the interplay of uncoordinated decisions, delivered at the pleasure of the developer.     

Developments in immersed tunnelling in Holland

Holland has 22 immersed tunnels (14 road, 5 rail and 3 utilities tunnels). Another three are under construction, and more are foreseen. The tunnels are of the concrete type, i.e., constructed without a steel shell. The paper describes developments in technology and in design philosophy since the first immersed tunnel was completed 52 years ago. These developments include, amongst others: the introduction of the Gina rubber gasket between elements; the division of elements into sections divided by flexible joints; the application (if possible) of longer elements (up to 268 m); the use of precast sections for tunnels that have a small cross-section; the omission of the watertight lining (made possible by cooling the concrete of the walls during the first days after pouring); various foundation methods (e.g., sand flow instead of sand jet system; piled foundations when necessary); the use of the excavation for the open ramps (or the part of the tunnel built on land) as a casting basin for the elements; the changed approach to casting basins now that well pumping is usually forbidden; and the transport of the elements across shallow locations and across the sea. It is emphasized that the current state of immersed tunnel technology is the result of a continuous international exchange of ideas and experiences.     

Experiences in radon-safe building in Finland

A study was made of radon-safe buildings in 300 Finnish low-rise residential buildings using data obtained from a questionnaire study. The study also aims at finding the main defects in design and implementation and how the guidance given on radon-safe buildings in slab-on-grade houses has been followed. According to the guidelines, the prevention of the flow of radon-bearing air from the soil into the house is recommended to be carried out through installation of aluminised bitumen felt and use of elastic sealants. Second, as a precaution perforated piping should be installed in the subsoil of the floor slab. The median indoor radon concentration in the houses was 155 Bq/m3. This is 32% lower than the median of the estimated reference values. The action level of 200 Bq/m3 was still exceeded in 40% of the houses. In most houses with slab-on-grade the prevention was based only on the installation of a sub-slab depressurisation system. Sealing was performed in a low number of houses. In 80% of houses with a sub-slab piping connected to an operating fan, radon concentration was below the action level of 200 Bq/m3. In houses with piping but no fan, the corresponding fraction was only 45%. Sub-slab piping without a fan had no remarkable effect on radon concentration. In houses with crawl-space and edge-thickened slabs, radon concentrations were low. The choice of foundation system thus significantly affects the indoor radon concentration. The importance of complete and careful sealing work should be stressed in advice and guides concerning radon prevention.     

浅谈建筑施工临时用电安全

针对由于建筑施工临时用电安全管理的不完善和不规范操作而导致大量工伤事故频频发生的问题,为消除用电安全隐患,对建筑施工临时用电安全管理进行了归纳和分析,并提出了整改意见,以确保现场人员及电气设备的安全运行。     

浅谈我国工程项目建设成本控制存在的问题

结合目前我国施工企业工程项目成本管理现状,对工程项目成本管理过程中存在的问题进行了较详细的分析,并提出了一些解决问题的办法,以做好项目成本控制工作,进而增强企业经济实力。     

Lead concentrations and isotope ratios in street dust in major cities in Greece in relation to the use of lead in petrol

Until recently, the most important source of environmental lead pollution in cities was thought to come from the combustion of leaded petrol. A simple way to monitor the extent of this phenomenon, used in a number of studies in the past, has been to measure lead levels in street dust. Nowadays, it would be expected that lead concentrations in urban dust would have decreased from earlier values, following the progressive reduction of lead in petrol over the past few years, and this hypothesis has recently been confirmed in Manchester, UK. The object of the present work is to determine levels of lead pollution in cities in Greece on 1997 and, if possible, to discover whether similar reductions in lead concentrations have occurred there also. Surveys have been conducted in Thessaloniki, Athens and Piraeus. Samples of roadside dust were collected from streets (categorised by traffic density), national gardens and school playgrounds, and lead was extracted by digestion with concentrated nitric acid. Lead concentrations were determined by graphite furnace atomic absorption spectrometry and lead isotope ratios measured by inductively coupled plasma mass spectrometry. Results for Thessaloniki showed that mean lead concentrations in all categories of location are similar to present levels in Manchester. Further, lead concentrations in dust in the busiest streets in Thessaloniki have fallen by about 55% since a previous study 17 years ago. In Athens and Piraeus, the lead levels in street dust are much higher and significant differences were observed between the various types of street. In particular, it was observed that lead levels in school playgrounds in these two cities were much higher than in similar locations in Thessaloniki and Manchester, with a possible hazard to children. Isotope ratio measurements showed that Thessaloniki's lead is isotopically distinct from that found in Athens and Piraeus, which presumably reflects differences in sources of supply.     

Changes in herbicide concentrations in Midwestern streams in relation to changes in use, 1989-1998

Water samples were collected from Midwestern streams in 1994-1995 and 1998 as part of a study to help determine if changes in herbicide use resulted in changes in herbicide concentrations since a previous reconnaissance study in 1989-1990. Sites were sampled during the first significant runoff period after the application of pre-emergent herbicides in 1989-1990, 1994-1995, and 1998. Samples were analyzed for selected herbicides, two atrazine metabolites, three cyanazine metabolites, and one alachlor metabolite. In the Midwestern USA, alachlor use was much greater in 1989 than in 1995, whereas acetochlor was not used in 1989 but was commonly used in 1995. The use of atrazine, cyanazine, and metolachlor was approximately the same in 1989 and 1995. The median concentrations of atrazine, alachlor, cyanazine, and metolachlor were substantially higher in 1989-1990 than in 1994-1995 or 1998. The median acetochlor concentration was higher in 1998 than in 1994 or 1995.     

谈城市历史保护规划的误区

由于缺乏起码的历史文化知识,忽视历史文化遗产的保护,错误的决策导致了建设性的破坏,要加强城市保护的教育,培养合格人才。     

Trends in ozone concentrations in Jerusalem

Ozone concentrations have been measured in Jerusalem since 1977 by a chemiluminescent ozone meter. During the last five years ozone levels have increased considerably. In order to test whether this increase reflected the growth in the number of motor vehicles or was caused by atmospheric conditions, the summer data of the last five years were analyzed. Ozone levels were characterized by the daily one-hour maxima; the atmospheric factors considered were temperature, insolation and stability. A multiple regression equation was computed and a correlation coefficient r = 0.77 obtained. The yearly mean reduced ozone levels showed a definite trend, which reflected the corresponding trend in the number of motor vehicles.     

Perchlorate exposure in lactating women in an urban community in New Jersey

Perchlorate is most widely known as a solid oxidant for missile and rocket propulsion systems although it is also present as a trace contaminant in some fertilizers. It has been detected in drinking water, fruits, and vegetables throughout New Jersey and most of the United States. At sufficiently high doses, perchlorate interferes with the uptake of iodine into the thyroid and may interfere with the development of the skeletal system and the central nervous system of infants. Therefore, it is important to quantify perchlorate in breast milk to understand potential perchlorate exposure in infants. In this study we measured perchlorate in breast milk, urine, and drinking water collected from 106 lactating mothers from Central New Jersey. Each subject was asked to provide three sets of samples over a 3-month period. The average ± SD perchlorate level in drinking water, breast milk, and urine was 0.168 ± 0.132 ng/mL (n = 253), 6.80 ± 8.76 ng/mL (n = 276), and 3.19 ± 3.64 ng/mL (3.51 ± 6.79 μg/g creatinine) (n = 273), respectively. Urinary perchlorate levels were lower than reference range values for women of reproductive age (5.16 ± 11.33 μg/g creatinine, p = 0.03), likely because of perchlorate secretion in breast milk. Drinking water perchlorate levels were ≤ 1.05 ng/mL and were not positively correlated with either breast milk or urine perchlorate levels. These findings together suggest that drinking water was not the most important perchlorate exposure source for these women. Creatinine-adjusted urine perchlorate levels were strongly correlated with breast milk perchlorate levels (r = 0.626, p = < 0.0005). Breast milk perchlorate levels in this study are consistent with widespread perchlorate exposure in lactating women and thus infants. This suggests that breast milk may be a source of exposure to perchlorate in infants.     

供热系统水力平衡技术措施在工程中的应用

本文分析了供热系统水力失调的主要原因,介绍了在工程中所应用的平衡阀、自力式差压控制阀、分布式二级变频循环水泵热水热力网水力平衡技术措施。通过工程实例分析了以上技术措施适用的范围及运行效果。     

安康市工程施工企业未来几年人才需求调查

为了不断提高工程类专业的办学质量,对安康市区主要施工企业或项目经理部未来几年人才需求状况进行了调查,同时提出相关建议,以期培养更多的该类专业人才,满足施工企业需求。     

Some results on Hg content in hair in different populations in Albania

The mercury content in hair, for exposed dental workers and unexposed groups of people living in Albania was studied. The influence of factors such as age, sex, body weight, fish consumption in the diet, number of dental amalgam fillings and time exposed to mercury, was determined. The mean value of mercury content in hair for the subjects under study (0.705 microg/g) was found to be lower than the value referred from the World Health Organization (WHO) for people who do not consume fish with a high methylmercury content (1-2 microg/g). A significant positive correlation of Hg content with the number of dental amalgam fillings, time under exposure and frequency of fish consumption in the diet was found. These correlations became stronger when exposed and unexposed groups of people were evaluated separately.     

历史视野中的乡土建筑——一种充满质疑的建筑

在当代建筑中,新乡土建筑可以看作是现代性与传统性的统一体。在《New Vernacular Architecture》老练精妙而又颇具可读性的介绍中,维基·理查森(Vicky Richardson)对建筑中的乡土性进行了图文并茂的分析和展示。这里节选的便是其导论部分,它为建筑的乡土性提供了一份详尽的历史性分析,展示了它是如何体现出笔者所描述的“充满质疑的建筑”(“architecture in denial”)观的——一种对于理念进展的质疑和一份对于“原生”建筑形式真实性的执信。     

北京私家园林的建筑艺术

北京私家园林中建筑占据了重要的地位,其中拥有厅堂斋馆亭榭轩楼台等不同形式,以及模仿江南的画舫,此外还经常设置戏楼和各种祭祀性建筑,并且拥有多种样式的门、廊、桥、墙等设施。这些建筑均采用典型的北方官式做法,用料考究,造型端庄,色彩相对浓烈,与山水花木景观很好地结合在一起,体现出与南方园林迥异的特色。结合大量具体实例,对北京私家园林的各类型建筑的基本特点进行分析,并对其整体的风格特征作了探讨和总结。     

浅谈我国高速铁路桥梁的几个问题

为了满足高速铁路列车安全运行和旅客乘坐舒适度的要求,总结了高速铁路桥梁的设计原则及对桥梁结构的新要求,并结合工程实践,对高速铁路桥梁设计的关键要点进行了介绍,指出高速铁路桥梁结构应具有安全可靠的特性,同时应具有足够的耐久性和良好的动力性能。     

我国建筑密封剂近期进展

近几年，我国建筑密封剂消费市场需求迅速扩大，产品品种及产量增长快，特别是硅酮、聚氨酯、聚硫类高中档弹性密封剂。本文对应发达国家的有关情况，着重讨论了我国建筑密封剂近期进展并提出一些建议。     

Typification of Fires in Buildings in Spain

Although the Dirección de General de Protección Civil (DGPC), an agency of the Spanish government, has been responsible for the collection of data and the statistical analysis of fires since 1985, it has not as yet issued any reports. It is true that a couple of studies have been made, but in neither case did they use a standardized methodology but relied simply on the heterogeneous information provided by the fire brigades which cooperated in the studies. At that time Spanish fire brigades did not have special units for professional fire investigation, nor was the information derived from standardized methodologies suited to research purposes. In addition, information was extremely scarce and basic, focussed only on the fire, the use of the building and personal data of the victims. In this context, the project for a Fire Investigation Unit in the Fire Brigade of Málaga (the sixth largest Spanish province in inhabitants) was set up. Although inspired in the methodologies used in the USA and in the UK, the aim was to create a customized methodology for the first scientific investigation of fires in Spain. Our research was conducted in 2007. Using the methodologies of the USA and the UK, our own methodological approach and the Spanish regulations, we drew up a questionnaire with 110 variables arranged into 6 modules. We studied 96 fires out of the 154 emergency fire calls received in 2007, having omitted some emergency calls for various reasons. Our results revealed that it was necessary to generalize the installation of fire extinguishers in residential buildings, to train the general public in the use of these devices, to promote the use of fire and smoke detectors in residential buildings, to encourage the inspection and control of old electric installations and to monitor the new installations, to generalize the implementation of emergency and evacuation plans and to design new systems and materials for the cabinets where hand-held extinguishers are stored.