燃气用埋地聚乙烯管材新旧国标GB 15558.1对比分析

针对已于2017年1月1日实施的2015版燃气用埋地聚乙烯管材制造国家标准(GB 15558.1),分析了其与已实施十余年的2003版标准在材料、管材、检验等内容上的区别,并以制造监督检验单位的角度,向混配料及管材制造商提出了一系列相关建议,同时提出了新标准实施后的监督检验要点,可供检验单位及相关生产制造单位参考。     

浅析燃气用埋地聚乙烯管材制造监督检验

燃气管道作为城市的能源输送系统一旦出现问题,会直接影响人们的正常生活,因此对于燃气管道的安全性要求很高,文章阐述了燃气用埋地聚乙烯管材制造监督检验的主要项目及常见问题,为今后监检工作提供一些理论依据和参考,确保此类产品的质量安全。     

燃气用埋地聚乙烯管材的生产技术与应用

介绍燃气用埋地聚乙烯管材的性能、生产技术、工艺、生产设备及产品性能指标、应用等。     

给水燃气用聚乙烯管材生产线

“给水燃气用聚乙烯管材生产线”是金石公司在吸收国外先进聚乙烯管材生产设备的基础上,根据中国实情研发的高质、高效聚乙烯管材生产线,可生产管材规格：φ20～φ630mm.     

国内外聚乙烯燃气管材专用料的发展概况

介绍了国内外聚乙烯(PE)燃气管材专用料的发展情况和主要生产厂家产品的性能,阐述了燃气用埋地PE管材国内标准和国际标准与欧洲标准的差异,并结合国内的研发和生产现状,提出了我国PE燃气管材专用料的发展方向。     

超高分子量聚乙烯管材性能分析与比较

对超高分子量聚乙烯管材与其他塑料管材的主要性能进行了分析与比较,结果表明ＵＨＭＷＰＥ管材具有优良的性能价格比,应用领域极广,是替代镀锌钢管,铸铁管,钢管等金属管道的理想管材。     

硅烷交联聚乙烯管材

在聚乙烯分子结构中仅有Ｃ、Ｈ两种元素,其分子式为♂ＣＨ２－ＣＨ２′ｎ,分子链呈线性结构,由于结构上的特点,使得聚乙烯不能承受较高的温度,机械强度不足,这样使其应用范围受到了限制,为了提高聚乙烯的性能,扩大应用领域,可采用交联的方法在聚乙烯分子链间相互交联,先是形成凝胶态,进而成为三向结构的热固性硬塑料,由此可提高聚乙烯的拉伸强度、热强度、防老化性和耐候性、尺寸稳定性、耐应力开裂性、耐溶剂性等一系列物理化学性能,所以交联聚乙烯管材可广泛用于制冷、制热、水处理、地埋式煤气、石油化工等国民经济各个领域…     

聚乙烯压力管材的生产过程控制

聚乙烯压力管材的生产过程中，原料的选择和预处理、管材挤出设备和工艺参数的选择以及生产中实际问题的解决是三个重要方面，对平衡管材的质量和经济效益具有重要意义。本文根据我公司的实际生产情况对这些问题进行探讨。     

高密度聚乙烯管材性能的研究

对不同类型催化剂生产的高密度聚乙烯管材料HD4801-1、HD4801-2进行性能分析。试验表明：HD4801-1的相对分子质量、熔体强度、氧化诱导期大于HD4801-2的,但剪切黏度小于HD4801-2的,HD4801-1的加工性能优于HD4801-2的。     

聚乙烯管材料要求和标准的发

简要介绍了聚乙烯管材的发展过程,分析了聚乙烯管原料标准、给水用聚乙烯管材和燃气用埋地聚乙烯管标准对原料性能的要求,可供聚乙烯管材原料生产厂生产和选用材原料参考,以提高我国聚乙烯管材开发和使用水平。     

燃气用聚乙烯管件注塑模具浇注系统的研究

依据聚乙烯管件壁厚超常规的特点，提出了聚乙烯管件浇注系统的设计原则；尤其建立了浇口大端尺寸(D)的经验公式，实践证明该式对聚乙烯管件模具浇道系统的设计具有较好的指导作用，据其所制得的浇道系统非常有利于生产效率的提高和外观质量的改善。     

燃气用聚乙烯管道热熔焊接工艺研究现状

介绍了各研究院在燃气用聚乙烯管道热熔焊接工艺优劣判别方面发展的新动向。聚乙烯管道在燃气管道等市政工程中的大量运用,迫切要求聚乙烯管道焊接工艺出台一套焊接工艺操作标准和评价体系。根据热熔焊接过程中的温度变化和压力变化来控制焊接接头的耐冲击性能、拉伸屈服强度以及避免焊接物理缺陷是一个值得研究和考虑的方向。     

冷热水输送管道系统用聚丙烯原材料的要求

结合冷热水用聚丙烯管道系统的国际标准、国家标准和国外管材原料的测试项目情况，分析了冷热水用聚丙烯管材原料的性能要求。文中还阐明了不同类型聚丙烯的定义，给出了PP－R和PP－B两种类型聚丙烯的简单区分方法。     

监理过程中对DL/T850电站配管标准的一点浅见

通过对DL/T850电站配管标准的理解,结合四大管道监理实践过程中发现的问题,提出了部分标准本身存在的问题及建议,希望对制造厂进行电站配管提供帮助,也为电站配管等管道配管标准的修订提供一定的参考意见。     

The application of x-ray powder diffraction for the analysis of synthetic organic pigments. Part 1: dry pigments

This paper presents x-ray powder diffraction data for over 200 synthetic organic pigments. These pigments, most manufactured in the last 130 years, are frequently found in modern works of art. Their identification is of interest in the field of art conservation for the purposes of dating works of art as well as making conservators and curators aware of issues with lightfastness and solubility. Most classes of these pigments, including β-naphthol, Naphthol AS, mono- and di-arylide yellows, quinacridones, copper phthalocyanines, benzimidazolones, and perylenes give good diffraction data. Some pigments, including certain triarylcarbonium and some other metal containing pigments, especially aluminum containing pigments, were found not to diffract. X-ray powder diffraction is of great use in distinguishing polymorphs of pigments such as quinacridones and copper phthalocyanines.     

Development of a numerical approach based on coupled CFD/FEM analysis for virtual fire resistance tests—Part A: Thermal analysis of the gas phase combustion and different test specimens

In the present two‐parted study, a numerical approach is shown to consider fire resistance tests in virtual space, including the combustion, thermal analysis of the test specimen, and the deformation process. This part is dealing with the combustion process and thermal analysis of different building materials tested in a fire resistance furnace. Instead of using coupled computational fluid dynamics (CFD)/finite element method simulation for the combustion and thermal heat conduction in the solid, which is commonly used in literature, the present approach considers these transport phenomena in one CFD simulation. This method enables a two‐way coupling between the gas phase and the solid material, where chemical reactions and the release of volatile components into the gas phase can occur (eg, release of water vapour from gypsum). To validate the numerical model, a fire resistance test of a steel door, which is a multilayer construction, and a wall made of gypsum blocks were experimentally and numerically investigated. Due to the chemical reactions inside the gypsum, water vapour is released to the gas phase reducing the flue gas temperature about 80 K. This effect was taken into account using a two‐way coupling in the CFD model, which predicted temperatures in close accordance to the measurement.     

Towards a methodology for the systematic analysis and design of efficient chemical processes: Part 1. From unit operations to elementary process functions

A successful intensification of a chemical process requires a holistic view of the process and a systematic debottlenecking, which is obtained by identifying and eliminating the main transport resistances that limit the overall process performance and thus can be considered as rate determining steps on the process level. In this paper, we will suggest a new approach that is not based on the classical unit operation concept, but on the analysis of the basic functional principles that are encountered in chemical processes.A review on the history of chemical engineering in general and more specifically on the development of the unit operation concept underlines the outstanding significance of this concept in chemical and process engineering. The unit operation concept is strongly linked with the idea of thinking in terms of apparatuses, using technology off the shelf. The use of such “ready solutions” is of course convenient in the analysis and design of chemical processes; however, it can also be a problem since it inherently reduces the possibilities of process intensification measures.Therefore, we break with the tradition of thinking in terms of “unit apparatuses” and suggest a new, more rigorous function-based approach that focuses on the underlying fundamental physical and chemical processes and fluxes.For this purpose, we decompose the chemical process into so-called functional modules that fulfill specific tasks in the course of the process. The functional modules itself can be further decomposed and represented by a linear combination of elementary process functions. These are basis vectors in thermodynamic state space. Within this theoretical framework we can individually examine possible process routes and identify resistances in individual process steps. This allows us to analyze and propose possible options for the intensification of the considered chemical process.     

Dynamic mechanical analysis of ethylene/1‐hexene copolymers: The effect of the catalyst type on the short‐chain branching distribution and properties of the amorphous and crystalline phases

Dynamic mechanical analysis was used to study ethylene/1‐hexene copolymers with different compositions, molecular weight distributions, and profiles of short‐chain branching (SCB) versus molecular weight. These copolymers were produced over a highly active supported titanium–magnesium catalyst (TMC), a highly active supported vanadium–magnesium catalysts (VMC), and a supported zirconocene catalyst. A higher fraction of the crystalline phase in the copolymers prepared with VMC was shown to result in higher elastic modulus values. β relaxation was found to be sensitive to the SCB distribution versus the molecular weight. The copolymers prepared with the zirconocene catalyst and VMC were characterized by more uniform SCB distributions and higher temperatures of β relaxation compared to the copolymers prepared with TMC. The mobility of the polymer chains at room temperature in the amorphous phase obtained by the spin‐probe method rose with increasing branch content in the copolymers and was not sensitive to different SCB distribution profiles. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44638.     

Development of an environmentally friendly protective coating for the depleted uranium-0.75 wt% titanium alloy: Part III: Surface analysis of the coating

Molybdenum oxide-based conversion coatings have been formed on the surface of the depleted uranium-0.75 wt% titanium alloy using either concentrated nitric acid or fluorides for surface activation prior to coating formation. The acid-activated surface forms a coating that offers corrosion protection after a period of aging, when uranium species have migrated to the surface. X-ray photoelectron spectroscopy (XPS) revealed that the protective coating is primarily a polymolybdate bound to a uranyl ion. Rutherford backscattering spectroscopy (RBS) on the acid-activated coatings also shows uranium dioxide migrating to the surface. The fluoride-activated surface does not form a protective coating and there are no uranium species on the surface as indicated by XPS. The coating on the fluoride-activated samples has been found to contain a mixture of molybdenum oxides of which the main component is molybdenum trioxide and a minor component of an Mo(V) oxide.