Range Of Construction Materials Research Articles

Prediagnostic serum polychlorinated biphenyl concentrations and primary liver cancer: A case-control study nested within two prospective cohorts

BackgroundPolychlorinated biphenyls (PCBs) were used in electrical equipment and a range of construction materials. Although banned in the United States and most of Europe in the 1970s, they are highly persistent in the environment and bioaccumulate. Whether PCBs are associated with liver cancer risk at general population levels is unknown. MethodsThis study consisted of 136 incident liver cancer cases and 408 matched controls from the Kaiser Permanente Northern California Multiphasic Health Checkup (MHC) cohort and 84 cases and 252 matched controls from the Norwegian Janus cohort. Sera collected in the 1960s–1980s were measured for 37 PCB congeners and markers of hepatitis B (HBV) and C (HCV) infection. Odds ratios (OR) and 95% confidence intervals (CI) for tertiles of each lipid-adjusted PCB were estimated from conditional logistic regression. We also examined the molar sum of congeners in groups: total PCBs; low, medium, and high chlorination; and Wolff functional groups. ResultsConcentrations of individual congeners from the 1960s/1970s sera ranged from 1.3-123.0 and 1.4–116.0 ng/g lipid among MHC cases and controls, respectively, and from 1.9-258.0 and 1.9–271.0 ng/g lipid among Janus cases and controls, respectively. Among MHC participants with sera from the 1960s, collected an average of 27 years before diagnosis among cases, the top tertile of PCBs 151, 170, 172, 177, 178, 180, and 195 was significantly associated with elevated odds of liver cancer (OR range = 2.01–2.38); most of these congeners demonstrated exposure-response trends. For example, ORtertile 3vs1 = 2.38 (95% CI: 1.22–4.64, p-trend = 0.01) for PCB 180. As a group, Wolff group 1b congeners, which are biologically persistent and weak phenobarbital inducers, were associated with increased odds. In MHC participants, ever vs. never HBV or HCV infection modified the PCB-liver cancer associations. There was little evidence of an association between PCBs and odds of liver cancer among the Janus cohort. DiscussionWe observed associations between a number of PCB congeners and increased odds of liver cancer among MHC, but not Janus, participants with sera from the 1960s/1970s.

Design of production of the range of construction materials on the basis of methods of the system analysis

The analysis of the modern approach to the choice of technological processes of production of heavy concrete products and its weaknesses were shown. It is proved that the technological process as an object is a weekly structured system due to the large degree of uncertainty associated with the human factor. It is established that development of new assortment approach to the choice of technological process of the production of construction materials differing in alleged accounting of functional purpose and service conditions of building constructions in a real estate object can be one version of the solution of this problem. The concept of the choice of optimum technological processes of production of construction materials distinctive in alleged accounting of functional purpose and service conditions of building constructions of real estate objects is developed. The technologies of mathematical statement and the solution of problems of optimization of technological processes of production of the range of construction materials differing in increase in degree of structure of system liaisons with external subsystems on the basis of standard mechanisms of the subject focused accounting of functional purpose and service conditions of building constructions and also standard algorithms of search of optimal solutions for defined the range are developed. Assessment of efficiency of assortment approach to a problem of optimization of technological processes of production of the range of construction materials including comparison of the characteristics of material received as a result of use of modern approach, assortment approach in the set parameters of management and assortment approach with expansion of a set of essential alternatives of technological process of production of the range of construction materials is executed. This assessment has shown that more perspective alternatives on qualitative content of characteristics of material are outside area of normative requirements and need justification.

The Concept of the Subject Focused Optimization of Technological Processes of Production of the Range of Construction Materials

Обосновывается несостоятельность современной парадигмы управления технологическим процессом производства ассортимента строительных материалов, строящейся на установлении нормативных требований к характеристикам материала и наладке производственных процессов под эти требования. Доказывается актуальность перехода к новому обоснованному производству ассортимента строительных материалов, предназначенному для изготовления конкретных типов строительных конструкций. Предлагаемый процесс отличается учетом функционального назначения и условий эксплуатации конструктивных элементов в объекте недвижимости и последующей формализацией данных требований к характеристикам строительного материала. Модель множества альтернатив строительного материала предлагается получить путем проведения ортогонального эксперимента в области варьирования выбранных параметров управления производственным процессом по заданной технологии. Процесс выбора оптимального строительного материала на представленном множестве альтернатив предлагается осуществлять на основе учета мнений потребителя и производителя в отношении конечного продукта. Также в соответствии с данной концепцией предлагается разработка алгоритмов решения задачи субъектно ориентированной многокритериальной оптимизации, работа которых направлена на поиск оптимальной для участников рынка производства альтернативы строительного материала в соотношении цены и качества. При оценке эффективности предложенного ассортиментного подхода в решении задачи оптимизации технологического процесса производства строительных материалов доказывается целесообразность обоснованного расширения множества существенных, имеющих перспективу использования альтернатив материала за счет обоснованного выхода за область проведения ортогонального эксперимента.

Noise Isolation Capability for a Range of Construction Materials Used In Iraq

This study deals with the ability of noise isolation for some type of concrete block used in Iraq. These materials are divided into groups and the noise isolation of these materials is tested by a device made locally. The results of these materials are compared and the following conclusions are reached: the sound isolation increases generally with the increase of the frequency, the increase is not linear but vibrated and a relative decrease in the sound insolation is noticed for the frequencies from 2000 Hz to 4000 Hz. The sound isolation increases with the increase of density of the material and vice versa. The sound isolation increases with the increase of the thickness if the density is stable. The sound isolation increases with the increase of the thickness of gap between two layers of a material and the highest value of the loss of sound transition corresponds a highest value of reducing of noise level. The lowest value of the noise reduction index corresponds to the lowest value of reducing of noise level. The most effective materials in reducing noise of the materials tested in this research are the solid concrete block to which a layer of Sandwich panel is added. The error percentage was less than 10%, particularly at the frequencies less than 1000 Hz. DOI: http://dx.doi.org/10.25130/tjes.24.2017.21

The Potential Influence of Progressive Construction Materials and Structures on Market Value of Buildings

Use of so called progressive materials and structures has been more and more common in architecture and building construction in recent years. We can simply describe them as materials and structures characterized in one or more characteristics with significantly above-average level of quality compared to materials and structures usually used today. The buildings where such elements are incorporated are usually characterized with higher value – architectonical, technical, economical, and environmental, or there was time and/or financial savings during their realization. Since the word ‘progressive’ is used in connection with whole range of construction materials, it is necessary to distinguish among them those which don’t really have such features. This paper is focused on the motivation of use of progressive construction materials and structures in buildings and their influence on market value, technical characteristics, and architectural level of the buildings.

A study on concentration measurements of radon-222 (uranium series) and radon-220 (thoron series) emitted to the atmosphere from tex (cementitious), red brick, and ecocarat among construction materials

The aim of this study was to measure, compare and analyze the air concentration of radon emitted to the atmosphere from a range of construction materials, such as tex (cementitious), red brick and ecocarat. The study methodology involved the use of continuous radon monitoring equipment (RTM 1688-2) to measure the concentrations of radon and thoron (Rn-220) contained in tex (cementitious), red brick and ecocarat. Among the three samples, tex showed the highest levels of radon and thoron emissions. When the radon emission concentration was estimated based on the materials required for construction per unit area (3.3 m2) in an actual building, tex showed the highest levels of radon and thoron emissions, with ecocarat exhibiting the lowest. Overall, this method is suitable for examining the effects of radon and for reducing the personal radiation exposure dose. Governments should be active in publicizing and encouraging the use of construction materials with lower levels of radon emission.

Briefing: New regulations will require chemical emissions testing

European regulatory requirements relating to construction products and the indoor environment are currently undergoing major review. When the legislation is finalised it is expected that manufacturers will need to implement chemical emission testing, both in-house and by an accredited third-party laboratory, for a wide range of construction materials, decorative products and furnishings as part of the CE conformance marking process. This article explores the regulatory background and how these changes will affect manufacturers.