土木工程施工技术分析

作为土木工程施工企业的技术和管理人员应该在加强土木工程施工技术分析的前提下,加强对土木工程施工传统技术的运用,提高对土木工程施工新型技术的推广,更好地实现土木工程施工技术指导实践、丰富理论的作用.本文在分析土木工程施工技术的特点基础上,对传统土木工程施工技术的运行进行了阐述,指出了土木工程施工新型技术运用的要点,对土木工程施工技术进行了技术上的分析和总结,做出了土木工程施工技术发展上的展望.     

建筑工程土建施工技术要点

文章首先论述了土建施工技术的重要性,然后分析了建筑工程土建施工技术要点,包括深基坑施工技术要点、钢筋施工技术要点、砖砌筑施工技术要点、混凝土施工技术要点、模板施工技术要点。     

建筑外墙装饰施工技术研究

介绍了当前建筑外墙装饰施工中比较常用的技术手段,如外墙基层处理技术、抹灰施工技术、涂饰施工技术、门窗施工技术、外保温施工技术、玻璃幕墙施工技术、饰面砖施工技术等,探讨了建筑外墙装饰施工中需要注意的一些问题,从而为类似工程提供借鉴。     

论房屋建筑工程施工技术与现场施工管理

为了有效提高房屋建筑工程的施工质量,分析了房屋建筑工程中的关键施工技术,具体包含基础施工技术、模板施工技术、钢筋施工技术、混凝土施工技术、节能施工技术及防渗漏施工技术,进一步研究了房屋建筑工程的现场施工管理措施,包含完善施工管理机制、强化管理人员责任感、提高施工材料管理水准,希望通过研究不断提高国内房屋建筑工程的施工质量,进一步有效优化房屋建筑后续的使用效果。     

桩基础施工技术在建筑工程中的应用

介绍了桩基础施工的基本概念,结合桩基础施工技术的特点和原则,论述了桩基础施工技术在建筑工程中的应用,对施工环节和施工技术进行了探讨,有助于提高桩基础施工技术在建筑工程中的应用水平。     

对风景园林工程施工技术的几点探讨

本文对风景园林施工中的技术以及技术问题进行了分析,并提出了一系列有助于强化风景园林工程施工技术的措施。本文认为,风景园林工程的施工技术包含了基本的建筑工程施工技术,还包括园林绿化施工技术,复杂的施工技术应用造成了施工中各种问题,而这些问题需要施工企业对参与施工的员工进行相应培训以及采取合适的施工管理措施加以解决。     

土木工程施工技术及未来发展趋势研究

随着科学技术的进步,我国土木工程施工技术也不断深化研究、改革创新。近年来,大量新型技术和材料被广泛应用于各类土木工程施工过程中,在很大程度上促进了土木工程项目施工目标的实现。本文阐述了我国土木工程施工技术的现状,介绍了我国土木工程施工技术新型创新技术的应用,分析了土木工程施工技术的发展趋势,并提出了土木工程施工技术发展的重点。     

土木工程施工技术的创新及发展

文章首先对土木工程施工技术进行了概述,其次说明了土木工程传统施工技术,再次探究了土木工程施工技术的创新,包括深基坑支挡技术,保证材料、设备及工艺的质量,预应力施工技术,注重施工技术应用的整体生态节能性,最后分析了土木工程施工技术的发展趋势。     

高支模施工技术在土建施工中的应用

模板施工技术是土建工程中的一种很重要的施工技术。随着建筑业的发展,这种技术得到了快速的发展,模板施工技术在土建工程主体结构施工中起到了关键的作用。高支模施工技术是模板施工技术中的一种典型的代表,它具有自己本身的施工特点和要求。本研究综述了高支模施工技术介绍、高支模施工流程及相关要求等内容。     

土建工程混凝土施工技术研究

随着社会的发展,人们提高了对土建工程施工质量的要求,而混凝土施工又是土建工程施工中普遍应用的施工方式,因此混凝土施工技术决定了土建工程施工的质量。而为了满足人们对土建工程质量的要求,就必须提高混凝土施工技术。本文对土建工程混凝土施工技术进行了进一步的研究,通过目前混凝土施工技术存在的问题,提出了相应的措施,为土建工程提高混凝土施工技术提供了有利的参考。     

Alteration of arsenopyrite in soils under different vegetation covers

The weathering of arsenopyrite (FeAsS) has been monitored in soils using an in situ experimental approach. Arsenopyrite in nylon experimental bags was placed in individual horizons in soils in spruce (litter, horizons A, B, and C), beech (litter, horizons A, B, and C) and unforested (horizons A, B, and C) areas and left in contact with the soil for a period of 1 year. The individual areas on the ridge of the Krušné hory Mts., Czech Republic, had the same lithology, climatic and environmental conditions. Scorodite (FeAsO₄·2H₂O) was identified as a principal secondary mineral of arsenic (As) formed directly on the surface of the arsenopyrite. Scorodite was formed in all the areas in all soil horizons. The amount of scorodite formed decreased in the series beech, spruce and unforested areas. In forested areas, there was a larger amount of scorodite on arsenopyrites exposed in organic horizons (litter, A horizon). The greater rate of arsenopyrite alteration in organic horizons in the beech stand compared to spruce stand is probably a result of faster mineralization of organic material with resulting production of nitrate and better seepage conditions of soil in this area. Speciation of As determined using the sequential extraction technique demonstrated that As was bonded in the soils primarily in the residual fractions prior to the experiment. The As content in the mobile fractions increased in the organic horizon in the forested areas after the experiments.     

Polycyclic aromatic hydrocarbons (PAHs) in agricultural soil and vegetables from Tianjin

Several types of vegetables were collected from two contaminated sites in Tianjin, China. The bulk soil and the rhizosphere soil samples were also collected from the same plots. Sixteen PAHs in the samples were measured. The total concentrations of PAH16 in the bulk soil from the two sites were 1.08 and 6.25 microg/g, respectively, with similar pattern. The concentrations of PAH16 and individual compounds in the rhizosphere were significantly higher than those in the bulk soil with mean values of 2.25 and 7.82 microg/g for the two sites, respectively. The contents of both total and dissolved organic matter in the rhizosphere were also higher than those in the bulk soil. Almost all PAH compounds studied were detected in both roots and aerial parts of the vegetables studied. Abundance of higher molecular weight PAHs in vegetable, however, was lower than that in soil. Concentrations of PAH16 in vegetable were higher than those reported in the literature for other areas. It appears that agricultural soils and vegetables in Tianjin, especially those from the site located immediately next to an urban district and irrigated with wastewater for several decades, are severely contaminated by PAHs. Among the eight types of vegetable studied, the highest concentration of PAHs was found in cauliflower. By average, the concentration of PAH16 in the aerial part of vegetables was 6.5 times higher as that in vegetable root, suggesting that foliar uptake is the primary transfer pathway of PAHs from environment to vegetables.     

中国绿道规划建设实践——从提级统筹到制度并轨

绿道在中国经过多年实践发展,在理论内涵、规划选线、综合效益等各方面都已有许多成果支撑.基于可公开获取的一系列文献资料,立足于绿道在中国各省市近20年的具体实践过程,梳理绿道在规划体系中的角色转变、在指标设置中的逐步细化和在管控上的落实方式,总结绿道实践在中国从提级统筹、常态认同到制度并轨3个阶段的发展变化,在展望绿道后...     

Health assessment of artisanal gold miners in Indonesia

Small scale miners use mercury to extract gold from ore in many countries. An environmental and health assessment was performed in Indonesia in two regions, Galangan in Central Kalimantan and Talawaan in Northern Sulawesi. The environmental assessment showed severe mercury contamination of the sediments, and increased mercury levels in local fish. For the health investigation 281 volunteers were recruited and examined by a standardized questionnaire, a neurological examination and neuro-psychological tests. A medical score was used consisting of significant factors of mercury intoxication. Mercury exposed workers showed typical symptoms of mercury intoxication, such as movement disorders (ataxia, tremor, dysdiadochokinesia, etc.). Blood, urine and hair samples were taken from any participant and analyzed for mercury. The mercury concentration in the biomonitors was high, partly extreme high in the working population, increased in the population living in the same habitat and low in the control group. By a standard protocol which includes a combination of threshold values of mercury in the biomonitors and a medical sum score the diagnosis of chronic mercury intoxication was made for highly burdened workers (amalgam smelters) in 55% in Sulawesi and in 62% in Kalimantan. Less exposed mineral processors and the general population in the mining areas were also intoxicated to a high percentage.     

Heterotrophic and mixotrophic growth of Micractinium pusillum Fresenius in the presence of acetate and glucose: effect of light and acetate gradient concentration

The main objective of this study was to determine the importance of secondary mechanism of organic carbon utilization (mixotrophic and heterotrophic modes) in addition to CO2 fixation (photoautotrophic mode) in the green alga, Micractinium pusillum Fresenius (chlorophyta), isolated from a waste stabilization pond. The growth was studied in the presence of acetate and glucose. The incorporation rate of 14C- acetate was measured in the light and in the dark at different concentrations. Finally, in order to underline the role of photosynthesis and respiration processes in the acetate assimilation, the effect of two specific metabolic inhibitors, a specific inhibitor of photosystem II (DCMU) and an uncoupler respiratory (DNP), has been studied. The obtained results showed that M. pusillum grows in the presence of organic substrates, i.e., glucose and acetate, in the light (mixotrophic growth) as well as in the dark (Heterotrophic growth). The growth was much more important in the light than in the dark and more in the presence of glucose than of acetate. In the light, the presence of acetate led to a variation of growth parameters mumax, iotaopt, and beta. The effect of acetate gradient on the growth of the microalga was severe as soon as its concentration in the medium was higher. The acetate uptake followed a Michaelis-Menten kinetic in the light as well as in the dark. The capacity of assimilation was slightly higher in the dark. The utilization of DNP and DCMU indicates that acetate incorporation is an active process depending on both anabolic (photosynthesis) and catabolic (respiration) metabolisms, corroborating the model of the Michaelis-Menten kinetic.     

Biomonitoring of trace metals in the Black Sea (Romania) using mussels Mytilus galloprovincialis

In a preliminary biomonitoring study, accumulated trace metal concentrations (Cd, Cu, Zn, Hg, Fe, Mn) have been measured in the mussel Mytilus galloprovincialis collected in the Black Sea, at 100 km from the Danube Delta in February 2001 and February 2002. Mussels were collected from four sites. In 2001 metal concentrations were determined in the whole soft body whereas, in 2002, the distribution of metals was evaluated in three different organs (gills, visceral mass and remaining tissues). The results obtained in 2002 confirmed those of 2001. For a given site, concentrations were always higher in the gills and visceral mass of mussels than in the remaining tissues. Principal component analysis allowed separating stations as a function of the metal concentrations in the organs. It is concluded that the mussels M. galloprovincialis are suitable biomonitors to assess changes in metal pollution in this coastal area of the Black Sea.     

城外造景：清末广州景园营造与岭南 园林的近代转型

清末广州中西交汇,景园营造新旧共存互动,推 动岭南园林的近代转型。其中,在繁荣的中西贸易和文化交 流,以及书院文化、士绅文化等的影响下,清末岭南形成了 以广州为中心、十三行行商为代表、官商士绅竞相造园的特 殊历史时期,其造园数量、规模、意匠等均在该时期达到岭 南古典园林发展的巅峰。这一时期也是岭南园林近代转型的 关键时期。在西方文化和清末洋务运动思想的影响下,广州 开始出现洋务花园、公园、市政绿化,以及校园绿地等新型 园林形式。这些具有公共性质的城市景致与新建私园一道广 泛分布在城墙以外,成为清末广州城市空间拓展与风景体系 形成的重要参与者。由于清末广州城外造景的繁荣,从时间 上开启了岭南园林的近代转型,在空间上使岭南园林的地域 性特征得以形成和辨识,其空间性与时间性界定了清末岭南 园林近代转型的物质及文化维度。梳理了清末广州具有代表 性的景园营造活动,在分析其动力机制的同时,探讨城外造 景之于岭南园林近代转型的意义。     

Factors affecting bulk to total bacteria ratio in drinking water distribution systems

Bacteria in drinking water systems can grow in bulk water and as biofilms attached to pipe walls, both causing regrowth problems in the distribution system. While studies have focused on evaluating the factors influencing the bacteria in bulk water and in biofilms separately, there is a need for understanding biofilm characteristics relative to the bulk water phase. The current study evaluated the effects of chlorine and residence time on the presence of culturable bacteria in biofilms relative to that in bulk water. The results showed that when no chlorine residual was present in the system, the median ratio of bulk to total bacteria was 0.81, indicating that 81% of the bacteria were present in bulk water, whereas only 19% were present in the biofilm. As chlorine concentration increased to 0.2, 0.5, and 0.7 mg/L, the median percentage of bacteria present in bulk water decreased to 37, 28, and 31, respectively. On the other hand, as the residence times increased to 8.2, 12, 24, and 48h, the median percentage of bacteria present in bulk water increased to 7, 37, 58, and 88, respectively, in the presence of a 0.2mg/L chlorine residual. The common notion that biofilms dominate the distribution system is not true under all conditions. These findings suggest that bulk water bacteria may dominate in portions of a distribution system that have a low chlorine residual.     

化学溶液和干湿循环作用下砂岩抗剪强度劣化试验及化学热力学分析

 为研究化学溶液和干湿循环共同作用下砂岩抗剪强度的劣化机制,在不同pH环境下,通过不同干湿循环次数后的单轴、三轴试验,计算出砂岩的黏聚力和内摩擦角,同时得到其与循环次数的关系式,进而获得砂岩在浸泡环境下抗剪强度随干湿循环次数的变化公式。根据砂岩的组成矿物及其百分含量,得到各种主要组成矿物在中性、碱性、酸性溶液中溶解的化学反应方程式,利用化学热力学的基本原理,确定各主要矿物在中性、碱性、酸性溶液浸泡下能否稳定。为了验证分析的正确性,对浸泡溶液中的部分离子(Ca2+,SiO2,Na+,K+)浓度进行测试。结果表明,酸性环境下,砂岩抗剪强度劣化最为严重,碱性次之,中性最轻。在酸性环境中,对抗剪强度影响较大的胶结物主要组成成分(长石、方解石)的性质不稳定,溶解反应能自发进行,而碱性环境中,对强度影响较小的骨料主要组成成分(石英)的性质不稳定,溶解反应能自发进行。酸性浸泡液中,方解石、钾长石、钠长石溶解出的Ca2+,K+,Na+的浓度明显高于中性和碱性液中Ca2+,Na+,K+的浓度,而碱性溶液中,石英溶解出的SiO2的浓度明显高于中性和酸性液中SiO2的浓度,与热力学分析结果一致。     

Cell phones for the spirits: ancestor worship and ritual economies in vietnam and its diasporas

Religion has been thriving in the Socialist Republic of Vietnam since ??i m?i, the onset of market reforms in the late 1980s. Votive paper offerings, part of spiritual and economic well-being, play a crucial role in performing religious practices in the socialist country as well as among diasporic Vietnamese. In urban Hanoi, material objects made from paper are traded in marketplaces and later burned in the streets, in temples and pagodas, in private yards and other places on special occasions in order to be transmitted to the ancestors. In the past few years, the range of votive paper offerings produced, traded, and sent to the deceased has expanded to include new forms and references to new media. Drawing on recent debates in the role of media in religion and in particular on technologies of mediation, I focus on the use of votive paper offerings in the sociocultural context of the Vietnamese spirit world. I explore how new media and media technologies are embedded in multilayered processes of mediation in Vietnam and its diasporas. Taking religious practices of burning votive paper offerings as an ethnographic example, this essay aims to contribute to ongoing debates on popular religion and the sacred life of material goods in late socialist Vietnam, on its transnational ties, and on the entanglements between religion, media and materiality.