岩溶地区采用振动沉管灌注桩存在的质量问题

水城盆地地下水位高，水量丰富，覆盖层厚度不大（一般小于20m)，岩溶裂隙发育，为解决施工降水困难以及施工降水对周围建筑，环境的影响，沉管灌注桩被广泛采用。但在使用过程中，出现了许多质量问题。通过大量实践，总结了沉积灌注桩在岩溶地区使用过程中易出现的质量问题及解决办法。     

沉管灌注桩基础工程施工的监理要点分析

以沉管灌注桩基础工程施工监理过程为例,总结了沉管灌注桩工程监理要点,并对沉管灌注桩施工监理中曾遇到的问题进行了分析,探讨了沉管灌注桩质量判定方法,期望能对沉管灌注桩基础工程施工监理提供一些借鉴。     

吹砂填海地质下的组合式吊打锤击沉管灌注桩施工技术

为避免沉管灌注桩施工过程出现带笼浮笼及拔空管现象，依托具体工程，在吹砂填海的复杂地质条件下，通过对沉管灌注桩工艺进行改进，发明了一种组合式吊打锤击沉管灌注桩施工技术。通过对相关关键技术的研究应用，显著提升了桩基础施工质量、节约了工期。该技术具有很强的可复制性，施工中获得的数据和经验可供相关工程参考。     

某复合地基工程案例的经验教训

某工程位于地质情况较为复杂的岩溶场地。根据实际地质情况,对局部工程部位采用素混凝土刚性桩复合地基加筏板基础形式和振动沉管灌注桩施工工艺。由于对振动沉管灌注桩工艺的特点认识不足,再加上施工过程中对一些工序质量控制不到位,造成最终桩基质量未能达到要求,只好改用其他桩基形式。本案例所提供的经验教训值得借鉴。     

沉管灌注桩施工常见质量问题的预防与处理

沉管灌注桩施工是一项专门技术,又属重要的隐蔽工程。文章分析沉管灌注桩施工中出现的常见质量问题,原因分析及处理办法,并提出针对性的预防措施。     

沉管灌注桩常见质量问题及防治措施

结合施工经验,对沉管灌注桩施工中常出现的质量问题进行了分析,并提出了相应的解决方法,以保证沉管灌注桩的施工质量,具有一定的参考价值。     

海相软土地基大直径沉管灌注桩桩身质量异常原因分析及处理方案

根据典型海相软土地区某工程沉管灌注桩桩身承载力和桩身完整性检测所发现的质量问题,结合沉管灌注桩施工工艺和工程地质条件,对海相软土地区沉管灌注桩桩身质量问题的成因作出了深入分析,同时提出合理的施工技术改进措施及建议。     

深回填土和岩溶发育地基桩基合理应用实例分析

对岩溶发育和深回填土地基基础选用进行了比选 ,并对所选活瓣桩尖振动沉管灌注桩在设计与施工方面提出了技术措施 ,最后阐述了深回填土地基选用活瓣桩尖振动沉管灌注桩的良好效果 ,其成果可供同类工程的设计施工利用和参考     

静压沉管灌注桩在建筑基础施工中的应用探讨

文章分析了静压沉管灌注桩的特点及应用意义,并结合工程实例,通过阐述静压沉管灌注桩施工工艺、控制要点,对静压沉管灌注桩施工质量存在的问题和不足提出了相应的解决措施。     

浅谈大直径沉管灌注桩的施工工艺

本文以工程实践,介绍了大直径沉管灌注桩施工工艺及施工过程中应注意的技术措施。针对厦门市厚层强风化区、孤石区复杂的地质条件,选择沉管灌注桩施工工艺程序及施工措施,并达到沉管灌注桩预定的质量目标。     

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.     

Mould Allergy in Schoolchildren in Relation to Airborne Fungi and Residential Characteristics in Homes and Schools in Northern Norway

Abstract During winter, airborne microfungi were collected from the homes and schools of 19 children sensitized to house dust mites (HDM) and 19 non-atopic control children in the community of Sør-Varanger, northern Norway. The samples were cultivated and microfungal growth was identified microscopically. Indoor humidity, temperature, carbon dioxide (CO₂), allergic symptoms and sensitization were registered. Symptom data and information concerning sociodemographic and housing conditions were obtained using a questionnaire. Penicillium was the most common microfungus in both homes and schools, followed by different yeasts, Aspergillus, Cladosporium and Mucor. The number of infected homes was equal in the HDM-sensitized and in the control group, but the mean aerospore counts were higher in the HDM-sensitized than in the control group. The lowest aerospore counts were found in the schools. High airborne spore counts appeared to be related to high indoor humidity. Only four children were sensitized to fungi, and these children were also sensitized to other allergens, such as animal dander and pollen, and suffered from asthma, allergic rhinoconjuncitivits (AR) and atopic dermatitis (AD). Three of these four children also had high counts of aerospores in their homes. However, no consistent association between mould growth and sensitization to moulds could be observed. The health implications of indoor fungal exposure may be multifactorial.     

Thermal acceptability assessment in buildings located in hot and humid regions in Brazil

The objective of this paper was to perform an analysis on thermal acceptability in naturally ventilated (NVB) and air-conditioned buildings (ACB) located in hot and humid climates in Brazil. Experiments were carried out in April and November 2005 with 1.301 questionnaires based on ISO 10551:1995(E). Indoor and outdoor climatic variables were monitored simultaneously. The results revealed that 53% of the occupants of NVB and 78% of ACB were thermally satisfied. However, some restrictions were observed with the applications of the following methodologies: ISO/FDIS 7730:2005(E); ANSI/ASHRAE Standard 55:2004; Adaptive Temperature Limits (ATG) and prEN15251: 2005(E). Differences were observed between thermal sensation (TSV) and predicted mean vote (PMV) and between the subject's percentages expressing thermal unacceptability of the environment and the PPD calculated according to ISO/FDIS 7730:2005(E).     

长沙市某大学教室内外空气品质调查

本文对长沙市某大学校园内三栋教学楼教室内外的空气品质进行了实地测量调查。在室内和室外同时对空气温度(Ta)、相对湿度(RH）、空气流速(V）以及二氧化碳(CO2)、一氧化碳(CO)、二氧化硫(SO2)、二氧化氮(NO2)、可吸入颗粒物(PM10)和甲醛(HCH0)等的浓度参数进行了测量。实地测量时间为2004年3月和4月两个月。测量结果显示CO2和PM10为典型大学教室中污染最为严重的两项指标：CO2的最高和平均浓度分别高达0．3229／0和0．1997％,而中国国家标准为0．100%。造成如此严重污染的主要原因是通风不足以及教室内人员密度过大;教室内PM10的最大和平均浓度分别为0．16mg／m^3和0．13mg／m^3,通过实验分析得出在室内人员密度不是非常大的情况下,室内PM10主要来自室外环境;而人员密度大到一定程度时,室内人员活动与PM10浓度则显示出了一定的正相关性。本文所测的其他污染指标均符合国家标准要求。并且在结论中也提出了一些解决问题的建议。     

Indoor air quality in hairdressing salons in Taipei

To improve indoor air quality and to protect public health, Taiwan has enacted the “Indoor Air Quality Act (IAQ Act)” in 2012. For the general public, the indoor air quality in hair salons is important because it is a popular location that people will often visit for hair treatments. However, only a few exposure assessments regarding air pollutants have previously been performed in hair salons. To assess the air quality of hairdressing environments in Taipei, ten hairdressing salons were included for a walk‐through survey in this study. In addition, the airborne concentrations of formaldehyde, volatile organic compounds (VOCs), CO₂, and phthalate esters were also determined in 5 salons. Charcoal, XAD‐2, and OVS‐Tenax tubes were used for the air sampling, while the samples were analyzed with gas chromatography/mass spectrometer. It was found that the products used in hair salons contained various chemicals. In fact, from the walk‐through survey, a total of 387 different ingredients were found on 129 hair product labels. The hair salons were not well ventilated, with CO₂ levels of 600 to 3576 ppm. The formaldehyde concentrations determined in this study ranged from 12.40 to 1.04 × 10³ μg m^?3, and the maximum level was above the permissible exposure limit (PEL) of US Occupational Safety and Health Administration (US OSHA). Additionally, 83% of the samples were with levels higher than the standard regulated by Taiwan's IAQ Act. The concentrations of VOCs and phthalate esters were below the occupational exposure limits (OELs), but higher than what was found in general residential environments. The hair products were considered as the major source of air pollutants because significantly higher concentrations were found around the working areas. The number of perming treatments, the number of workers, and the frequency of using formaldehyde releasing products, were found to be associated with the levels of formaldehyde. This study indicates that efforts are needed to improve the indoor air quality in hairdressing salons in Taipei.     

Determination of nitroarenes in precipitation collected in Kanazawa, Japan

Eight nitroarenes, 1,3-, 1,6- and 1,8-dinitropyrenes, 1-, 2- and 4-nitropyrenes, 6-nitrochrysene and 2-nitrofluoranthene, in precipitation collected in Kanazawa were determined. The nitroarenes in the precipitation were concentrated onto solid phase extraction cartridges, and identified with high-performance liquid chromatography with chemiluminescence detection. The nitroarene concentrations in the precipitation were in the range 0.016-15 pmol/L, and the nitroarene composition tended to be the same as that in airborne particulates. 1-Nitropyrene in river water and seawater were also determined. 1-nitropyrene concentrations on the days after rain (19-110 fmol/L) were higher than those on the days before rain (4,11 fmol/L). Moreover, 1-nitropyrene concentrations in the river water were much lower than those in the precipitation, but were higher than those in the seawater. These results suggested that the nitroarenes in the precipitation and the river water came from airborne particulates.     

Tree-ring elemental concentrations in oak do not necessarily passively record changes in bioavailability

Elemental concentrations in tree-rings from red and white oak trees at six sites across Southern Ontario, Canada, were assessed to determine whether they passively record changes in geochemical cycling in the presence of environmental stress. Periods of stress were defined as sustained periods with elevated delta(13)C values in tree-rings relative to atmospheric CO(2) during the same period. In some trees, nutrient concentrations (Ca, Mg, Mn) were erratic during historic periods of stress while chemically similar non-nutrients (Ba, Sr) and the anthropogenic pollutant Pb were not. Tree-ring concentrations of Ca and Sr were related to bedrock type and leachable concentrations in the soil. In contrast, tree-ring concentrations of Mg were not related to bedrock type, although Mg concentration in the soil leachate was. Tree-ring Mn, Ba and Pb concentrations were not related to bedrock type or soil concentrations, but were inversely related to soil pH. Erratic behavior of nutrient elements during historic periods of stress suggests that some nutrient concentrations in the environment were not always passively recorded by tree-rings.     

Trends in productivity improvement in the US construction industry

Surveys of the top 400 US contractors were conducted in 1979, 1983 and 1993 to identify the areas with potential for productivity improvement in the construction industry. The trends in the findings of these surveys are observed and interpreted. The results indicate that cost control, scheduling, design practices, labour training, and quality control are the functions that consistently over the years are perceived as having considerable room for productivity improvement, whereas materials packaging and foreign developments in construction technologies are perceived consistently as functions that do not have much effect on improving construction productivity. The functions that were identified as needing more improvement in 1993 compared with the previous surveys were prefabrication, new materials, value engineering, specifications, labour availability, labour training, and quality control, whereas those that were identified as needing less improvement than in the previous surveys were field inspection and labour contract agreements. Also, respondents indicated consistently over the years that they are willing to participate in activities related to improving construction productivity but are not interested in funding any such activities.     

Prolift材质医用网片在家兔体内的生物相容性及缩变的实验研究

目的探讨Prolift材质医用网片在动物体内的生物相容性及面积缩变度。方法将6只新西兰家兔按随机数字表法分为3组：A组、B组和C组,每组2只。每只家兔腹部皮下放置10 mm×40 mm Prolift材质医用网片10片。3组家兔术后均采用氟哌酸50 mg.d-1加入饲料中口服,抗感染3 d。A组中1只家兔出现感染为A1组,1只未感染的家兔为A2组;B、C 2组家兔均未出现感染。A组术后第14天处死家兔,B组术后第30天处死家兔,C组术后第90天处死家兔,各组家兔分别取出Prolift材质医用网片及肌肉组织,以家兔自身的皮下组织及肌肉组织作为对照组。用游标卡尺测量Prolift材质医用网片的长、宽值,计算面积及Prolift材质医用网片面积缩变度。同时行组织切片,在光学显微镜下观察各组家兔的炎症反应、纤维组织囊壁形成情况。结果 A1组家兔术后第3天出现植入Prolift材质医用网片部位感染,各组家兔均无血清肿、侵蚀、暴露及排斥反应等。A1、A2、B、C 4组家兔Prolift材质医用网片面积缩变度分别为（21.84±0.05）%、（3.13±0.03）%、（2.30±0.03）%、（2.50±0.03）%,A1组家兔Prolift材质医用网片面积缩变度和处死后的网片面积与A2组比较差异均有统计学意义（均P〈0.05）,家兔Prolift材质医用网片面积缩变度和处死后的网片面积A2组、B组、C组之间比较差异均无统计学意义（均P〉0.05）。A2、B、C 3组家兔炎症反应分级分别为Ⅲ级、Ⅱ级、〈Ⅰ级,纤维组织囊壁形成分别为Ⅲ级、Ⅱ级、〈Ⅰ级。结论 Prolift材质医用网片植入家兔体内后具有良好的抗缩变性能和生物相容性,但感染可能是引起网片缩变的重要因素。     

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.