北京市居室几种常见有害气体全年污染水平调查

通过全年两月一次随机选择北京市共34处办公室和35处家居作为样点,按照国家标准方法采集氨、苯、甲醛、总挥发性有机化合物和氡几种常见有害气体,并进行浓度水平的分析,调查其污染水平及季节变化情况。结果表明:北京市室内环境中氨、甲醛和总挥发性有机化合物的超标现象严重,苯属轻度污染,氡完全符合室内环境质量标准。不同季节污染物水平表现出差异:甲醛浓度在7月最高,氨、苯浓度在9月最高,氡浓度在春季左右达到最高,总挥发性有机化合物成分复杂,随时间变化规律性不明显。     

室内挥发性有害有机物限量标准研究

室内挥发性有害有机物的种类繁多，我国现有室内空气质量标准中有机物的限量指标只有甲醛、苯、甲苯、二甲苯、TVOC5种。我们通过研究发现室内空气中17种有机挥发性有害物质出现的频率较高，浓度较大，且对人体健康有很大的危害，世界各国和各地区的空气质量标准分别对这17种物质中的部分组分给出了安全限量。通过科学分析我们建议了涵盖甲醛、烷烃类、卤代烃类、苯系物等的室内挥发性有害有机物限量标准，使我国的室内空气质量控制指标更具有效性和针对性。     

多溴联苯醚降解的代谢途径

添加型阻燃剂多溴联苯醚(PBDEs)由于具有优异的阻燃性能,已被广泛应用于各种消费品中。PBDEs具有低水溶性,会强烈吸附有机物,导致PBDEs在环境介质和食物链中大量富积,对人类和动物都造成巨大危害。对多溴联苯醚生物降解、光降解和零价铁降解过程中的代谢途径和代谢过程中所需的酶进行综述,为多溴联苯醚的修复提供理论基础。     

新装修房屋室内空气质量预测方法

分析装修过程中使用较广泛的材料表面的污染物释放量与各个影响因素之间的关系,测试单位时间内不同装饰装修材料表面总挥发性有机物释放量。在此基础上拟合装饰装修材料表面的甲醛及有机物释放量公式,计算各类材料的污染因子,从而能够从定量的角度描述室内环境污染物情况,使得预测装饰装修后的住宅室内污染物浓度成为可能。     

高温热解析在多环芳烃污染土修复中的应用

多环芳烃(PAHs)是一类重毒污染物,其污染土壤对人类的健康造成了严重危害,所以对污染土壤进行修复势在必行。首先讨论了处理多环芳烃(PAHs)污染土壤的多种可行技术;然后详细介绍了回转窑高温热解析在北京某焦化厂多环芳烃污染土壤修复中的应用及效果,研究发现回转窑高温热解析技术不仅能有效去除污染土中的有机污染物,而且还能抑制二噁英等剧毒物的产生。     

关于GB/T18801－2008《空气净化器》中存在问题的探讨

在执行新版空气净化器标准GB/T18801－2008过程中发现：气态污染物采样和分析方法存在一定的问题,影响新标准的正常执行。本文以氨、甲醛、苯、总挥发性有机物（TVOC）4项气态污染物的检测方法为例,对标准中存在的关于气态污染物测试问题进行说明和讨论。     

白洋淀表层沉积物中的多卤代芳烃及其潜在风险

采用GC-MS/MS技术对45个白洋淀表层沉积物(0~5 cm)样品中的三类(多溴联苯、多溴联苯醚和多氯联苯)多卤代芳烃(PHAHs)进行分析。实验发现多氯联苯(PCBs)是优势污染物(20.57 ng.g-1.dw),PCB28,52,66,138,156和170是被检出的主要同族体;多溴联苯(PBBs)和多溴联苯醚(PBDEs)在沉积物中的检出浓度相对较低(0.47 ng.g-1.dw和1.78 ng.g-1.dw),PBDE28和PBDE47是最具支配地位的PBDE同族体,分别占PBDEs总量的16%和21%。实验结果与国内外最近的文献报道值相比较,显示这三类PHAHs在沉积物中的浓度处于低污染水平,引起的潜在风险也相对较低。     

新书简介

由于室内环境中的甲醛污染来源渠道比较复杂、假冒伪劣装饰装修材料和家具不断出现、人们对甲醛污染防控缺乏科学有效的认识和防控甲醛污染的产品和技术在不断发展中等原因,室内环境甲醛污染还是我国目前新装修家庭的室内环境主要污染物,解决室内环境中的甲醛污染问题仍然是我们国家室内环保行业的重要任务。     

水溶性涂料新标准“七一”施行

国家环保总局针对水溶性涂料制定的新标准规定，对人体有害的挥发性有机物VOC含量由原来的250g／L降为200g／L，从2007年7月1日起实行。达到这一标准的产品（已获得“十环”标志）继续使用我国“十环”环保产品标志。涂料中释放出的甲醛、苯、甲苯、二甲苯等有毒气体，长期吸入会破坏人体免疫功能，导致白血病，尤其妇女、儿童最为敏感，而孕妇吸入苯会导致胎儿畸形或流产。国际卫生组织早已把苯列为强烈致癌物质。此次，国家环保总局根据实际国情，针对溶剂型油漆首次制定了一个相应的标准，对挥发性有机物VOC进行限量规定——硝基类750mg／L，聚氨酯类600mg／L，醇酸类550mg／L，苯含量0．5％。所以购买溶剂型木器漆时，要查看有没有国家权威部门颁发的测试报告。这里要提醒消费者，使用这类产品施工完后，最好通风2～3个月再入住，以避免苯类、甲醛等有机挥发物和残留的游离TDI对人体的伤害。     

第八讲：室内环境污染防治知识

一、室内环境中有害物质对人体的危害一般室内环境污染物按照污染物的性质区分,大致可以划分为以下几类:(1)化学污染物:主要包括从装修材料、化妆用品、涂料、厨房等地方释放或排放出来的包括氨、氮氧化物、硫氧化物、碳氧化物等无机污染物及甲醛、苯、二甲苯等在内的有机污染物;     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...