PVC塑料型材老化试验与思考

本文针对PVC塑料型材老化现象,从引起PVC塑料型材老化的基本观点、人工老化试验、不同地区气候老化影响、老化导致变色的影响因素等方面进行了讨论,提出了解决PVC塑料型材老化现象意见.     

PVC塑料型材老化试验与思考

本文针对PVC塑料型材老化现象,从引起PVC塑料型材老化的基本观点、人工老化试验、不同地区气候老化影响、老化导致变色的影响因素等方面进行了讨论,提出了解决PVC塑料型材老化现象意见.     

自然气候老化测试及应用

描述自然气候条件对材料老化的影响以及对预测材料不同应用方向等方面的影响。通过对不同地点,不同老化方法的比较,重点介绍了目前国际上使用的老化方法－直接曝晒,黑板箱曝晒,间接曝晒,自然加速老化等多种标准方法的特点,使用的局限性以及对材料老化结果的影响,并详细介绍了适用于自然老化地点的选择,主要影响因素等等。文章在分析多种老化方法的同时,指出了各种方法的适用性,这对材料老化方面的研究有很大的参考价值和指导意义。     

聚酰胺及其改性材料自然老化行为研究及预测

在自然环境(武汉)下进行了两年半的老化曝晒实验,随着老化时间的增长,聚酰胺材料的吸水率逐渐增加,力学性能下降,表面出现了不同程度的裂纹.通过吸水率测试和力学性能的比较,发现环境湿度影响聚酰胺老化过程中力学性能变化,湿度越大,材料力学性能下降越快;改性后,即添加了玻璃纤维后的聚酰胺,能够在一定程度下减缓材料老化行为.对材...     

不同颜色油漆试板的耐光老化性能分析

汽车工业的发展的和汽车工艺的进步,推动了汽车外观、颜色等方面的多样化发展。消费者通常以高安全性、高保值率、视觉美观等为主要依据选择车漆颜色,较少考虑车漆的耐光老化性,这种消费心理导致很多生产厂家对车漆的耐光老化性缺少重视。本文通过研究两家油漆厂家制作的不同颜色油漆试板,分析其耐光老化性能优劣,为生产厂家提高不同颜色油漆耐光老化性能及其研究方向的选择提供参考。     

两地区涂层板自然老化和评价方法的比较

将不同颜色(红色、海蓝、白灰)的三种涂层板分别置于热带乡村气候区和热带海洋气候区进行大气暴露5年,每年对样品进行外观评估、颜色和光泽测量;收集相关气象数据,比较两地区涂层老化的差异;建立涂层板老化曲线模型,比较不同评估方式,得出光泽和色差模型可以反映材料的老化过程。     

汽车皮革耐候性测试研究

分析汽车皮革老化的原理,然后列举汽车皮革常用氙灯试验条件,引用GMW 14444内饰件自然老化试验条件,比较加速试验与自然老化试验的异同点;比较汽车皮革老化后性能数据变化趋势,获得黄色指数和颜色数据更适合皮革材料老化趋势分析。     

碳纤维增强复合材料的环境适应性研究进展

概述了碳纤维增强基复合材料在环境适应性方面近十年的研究进展,从机理、最新研究进展两个方面着重阐述了湿热老化、高低温交替变化老化和紫外辐照老化,以及低能冲击损伤在环境因素作用下对碳纤维复合材料性能的影响,并简要地提出了碳纤维复合材料在环境适应性方面的发展方向。     

外绝缘用液体硅橡胶老化现象的微观表征

本文针对近年来出现在一些变电站SF6电压、电流互感器的液体硅橡胶绝缘护套出现龟裂老化这一现象,对发生老化的硅橡胶材料进行了性能测试和试验,并利用红外光谱分析、XPS分析、热失重等手段分析了其微观结构和物质组成的变化。研究发现老化后的液体硅橡胶中Si-C、Si-O官能团和Si、C、O元素的相对含量发生了变化,且随着老化程度的增加呈现出较为明显的规律,老化越严重,Si-C键含量越少,C元素的含量越少,O元素含量越多。本文认为,用官能团含量、元素相对含量可以准确地表征液体硅橡胶材料的老化程度。通过对不同老化程度的液体硅橡胶进行的憎水性、耐漏电起痕性能的试验也证实了本文的观点。     

我国典型气候环境下塑料老化严酷度表征模型研究

太阳辐照、温度、湿度是影响塑料老化的最主要的环境因素。基于以上的三种环境因素,分别建立模型进行量化分析,形成环境条件对塑料老化的严酷度表征模型。应用模型可以通过两个地点的环境条件推测塑料在两地老化的严酷度,并进行比较。通过开展高分子参考材料(聚苯乙烯和聚碳酸酯)在我国典型气候环境的自然老化试验,采用塑料老化过程的光学性能数据对严酷度模型进行验证,表明严酷度模型能够反应塑料在我国典型气候的老化严酷度。     

PVC-based composite material containing recycled non-metallic printed circuit board (PCB) powders

The study is directed to the use of non-metallic powders obtained from comminuted recycled paper-based printed circuit boards (PCBs) as an additive to polyvinyl chloride (PVC) substrate. The physical properties of the non-metallic PCB (NMPCB) powders were measured, and the morphological, mechanical and thermal properties of the NMPCB/PVC composite material were investigated. The results show that recycled NMPCB powders, when added below a threshold, tended to increase the tensile strength and bending strength of PVC. When 20 wt% NMPCB powders (relative to the substrate PVC) of an average diameter of 0.08 mm were added, the composite tensile strength and bending strength reached 22.6 MPa and 39.83 MPa, respectively, representing 107.2% and 123.1% improvement over pure PVC. The elongation at break of the composite material reached 151.94% of that of pure PVC, while the Vicat softening temperature of the composite material did not increase significantly compared to the pure PVC. The above results suggest that paper-based NMPCB powders, when used at appropriate amounts, can be effective for toughening PVC. Thus, this study suggests a new route for reusing paper-based NMPCB, which may have a significant beneficial environmental impact.     

Polyvinyl chloride used as a chlorinating and a reducing agent

Polyvinyl chloride (PVC) or vinyl is a recyclable material. It can be used as a chlorinating and a reducing agent. Two tests of chlorination and reduction of two different samples of jarosite and hematite were realized using PVC, results are presented in this paper. The chlorination test shows that the HCl gas produced from PVC and heated at ≈250°C can be used as a chlorine source to recover as chlorinated compounds the valuable metals such as Zn, Pb contained in jarosite. The XRD reveals the presence of lead and zinc chlorides in the condensates obtained. The second test of reduction was conducted using a mixture of PVC and hematite treated in a nitrogen atmosphere between 200 and 1000°C. The results show that at low temperature, PVC produces HCl and with kinetic consideration, no reactions can be observed with hematite. However, at high temperature, the weight of the hematite sample decreases by ≈15%, due to the reduction of hematite to iron metal.     

COMPUTER-AIDED PLANNING FOR MULTIPLE-PURPOSE RESERVOIR OPERATING POLICIES1

ABSTRACT: Computer-aided planning (CAP) for multiple-purpose reservoir operations involves use of state-of-the-art simulation and optimization methods, color graphic displays, and interactive computing interfaces. These technologies were integrated into a coherent system that has user-friendly interfaces to help the process of communicating reservoir system operations, solicit planning participant preferences and valuation judgments, and provide understandable feedback of system performance. The CAP system was imbedded in a comprehensive public involvement program that paralleled the reservoir operating policy modeling process, as part of multipurpose reservoir operations planning on the Great Plains Reservoirs in Colorado. Experience with the approach indicates the involved publics can quickly learn of reservoir system limitations and opportunities, and can indeed participate in the operations planning process.     

Industrial metabolism of PVC in China: A dynamic material flow analysis

In China, the rapid development of the polyvinylchloride (PVC) industry will inevitably lead to various environmental problems. This paper studies the PVC metabolism further by (1) constructing dynamic models based on material flow analysis (MFA), (2) introducing calculation on detailed lifetime distribution of different types of products and recycling, and (3) obtaining the performances of waste emissions and accumulation as a function of raw material input and time. Based on system evolution theory and population development models, the developing trend of the PVC industry is studied, and annual consumptions in future years are predicted. The annual emission and accumulation after metabolism can be calculated by tracking the amount of raw material input, existing form and process flow for a single year (2003), as well as over a longer period (from 1958 to 2048) in China. Analysis indicates that over 0.6 billion tons of PVC waste will have accumulated in the environment by the end of 2050. In this scenario analysis, the effects of product structure, lifetime distribution, mechanical recycling, chemical recycling and incineration on waste output are all taken into consideration. The product metabolism process can be decelerated by changing these factors appropriately. However, mechanical recycling and chemical recycling are the most effective solutions.     

嘉陵江南充段水质监测分析与综合评价

本文依据南充市2011年~2013年嘉陵江流域水环境监测统计资料,采用单因子评价法和综合污染指数法分析与综合评价嘉陵江南充段水质污染特征和现状。结果表明,研究河段内的清泉寺、小渡口和李渡断面总氮含量超标属于地表水Ⅳ类水体,超标倍数年均值分别0.21、0.35、0.37,其他监测项目符合Ⅲ类水质标准,均属于轻度污染。彩虹桥断面总氮、总磷、氨氮、CODMn和BOD5含量超过Ⅲ类标准,均在Ⅳ~Ⅴ类范围,属于中度污染。综合分析嘉陵江南充段,水质主要污染指标为总氮,综合污染指数为0.38,水质综合评价结果属轻度污染。该评价结果能为嘉陵江流域的水环境保护和科学治理提供依据。     

基于模糊综合评价法与单因子指数评价法的水质评价

通过2012年5月至10月对凡河榛子岭水库上游河段的水质监测,采用模糊综合评价法对凡河榛子岭水库上游河段水体的水质状况进行了综合评价,同时与单因子指数评价法评价结果进行对比分析。结果表明,2种评价方法的评价结果存在较大差异,采用模糊综合评价法评价得到的水质评价结果相对较好;采用模糊综合评价法评价,仅6月的杨坟沟、岱海寨断面及9月的杨坟沟断面的水质为Ⅴ类,其他月份各监测断面的水质均符合Ⅲ类水质标准要求;而采用单因子指数评价法的评价结果仅9月份的杨坟沟断面的水质达到Ⅱ类水质,其余各月三个断面监测的水质均超出Ⅴ类水质标准。在水质评价中,应根据评价目的合理选择水质评价方法,使水质评价结果更为准确。     

温度循环对键合及芯片烧结性能的影响分析

温度循环针对材料间的热胀冷缩特性,产生蠕动和疲劳损伤效应。半导体器件在温度循环试验过程中封装可靠性随温度循环时间逐步退化。针对一种半导体器件的键合强度、芯片剪切强度、芯片烧结空洞随温度循环次数的退化情况进行了分析。     

中国省域旅游企业综合实力分析--兼析如何提升安徽省旅游企业综合实力

从旅游企业规模和企业效益两方面入手,构建出中国省域旅游企业综合实力分析的2类10项指标体系,利用具有全国可比性的权威性数据,借助统计学分析软件SPSS,采用因子分析法对中国各省域旅游企业综合实力进行了详细测度和具体分析.最后针对安徽省旅游企业综合实力落后的问题,提出了相应对策.