Papers by Keyword: Environmental Degradation

Abstract: The approach suggested in this analysis stems from basic material science laws and considers that any environmental degradation of polymer composites ultimately consists in chemical link and cohesion force alteration. Such alteration leads to the modification of material viscoelastic characteristics that can be measured through stress relaxation or creep. Then the analysis deals with the applicability of the time-temperature shift principle for prediction test in cases involving environmental degradation. It is demonstrated that the shift factor as determined from Arrhenius Law needs to incorporate an additional term to account for the variation of the activation energy of the chemical and physical degradation. The method leads to excellent prediction of the time and environment dependent material strength.

Abstract: The environmental data (carbon emissions, industrial wastewater discharge, exhaust gases emissions and solid waste production.) and economic data (Per Capita GDP) from 1985 to 2010 was selected to fit environmental Kuznets curve (EKC). The results showed that all the EKC models were significantly fitted (p<0.01), the EKC shapes of Per Capita GDP (PCGDP) between carbon emissions, industrial exhaust gases emissions, and industrial solid waste production were inverted-U shape, respectively. The EKC shape of PCGDP and industrial wastewater was inverted-N shape. This study suggested that Henan Province is still at the stage of industrial development, and EKC turning points of carbon emissions, industrial exhaust gases, and industrial solid waste production have not been reached. Therefore, it is necessary to optimize and adjust energy-depended industry structure to improve environment quality and welcome EKC turning points coming as soon as possible.

Abstract: With the transformation of China's urbanization and accelerated pace of urban agglomeration, increasing construction waste has brought the conflict between the development of urban and environmental degradation. To use recycled aggregate (RA) to a certain extent eased pollution on the environment. Because of the source of RA cause exist quality poor stability, dispersion and other shortcomings. By test, comparative analysis the differences indicators between recycled aggregate and natural aggregate, brick gravel content of recycled coarse aggregate performance indicators in particular made ​​a crushing value performance test. As the research properties of recycled aggregate and adapted to the local grading standards provide a frame of reference.

Abstract: With the aggravation of water resources scarcity in northeast China at present, the area of the wetlands in the watershed has gradually decreased, and the ecotope is getting worse. In this article we take Xianghai wetland and Zhalong wetland as an example to study the process of ecological water requirement, so as to provide the basis for water environment protection. The results show that the suitable ecological water requirement of Xianghai wetland is 191.19 million m³, and the minimum ecological water requirement of Xianghai wetland is 74.32 million m³. While the suitable ecological water requirement of Zhalong wetland is 559.63 million m³, and the minimum is 217.39 million m³. The wetlands in northeast has four ecological water requirement characteristics, which includes that the northeast wetland ecological water requirement process assumes an M type; May is the month having the highest ecological water requirement of the wetland; the wetlands’ ecological water requirement shows a sharp decline in July; and the wetlands ecological water requirement becomes less in winter. The wetlands should choose a right time to make an ecological water supplement for the wetland, in order to alleviate the water shortage condition, and maintain the wetlands’ structure and function to play them normal roles.

Abstract: The abuse of land is devastating our country: environmental disasters (landslides, floods, mudslides, etc.) are becoming more frequent because of the abandonment of agricultural lands and an inadequate care of the land, particularly in the inland areas. But Calabria, and the province of Reggio Calabria, in particular, has agricultural vocations that makes it unique in the Italian panorama and there could be development opportunities for the region, not only in the agriculture sector but also in the recovery of the historic centers with an innovative use of waste materials coming from the production of bergamot, or citrus, for the restoration of historic buildings and vernacular architecture. From a metropolitan city point of view, we must put an end to the soil consumption in favor of the recovery and the enhancement of endogenous resources, utilizing innovative techniques and innovative methods we can diversify the use of existing resources to make them more productive.

Abstract: The Yellow River Delta of China is a unique region with vulnerable ecosystems and under the most pressure from various risk sources. In recent years, this region has experienced rapid economic growth. However, the delta is vulnerable to environmental hazards and is seriously affected by such natural and anthropogenic hazards as coastal erosion, land subsidence, saltwater intrusion, soil salinization and groundwater pollution due to natural disasters and human activities, thereby increasing the risk of environmental degradation in the Yellow River Delta.

Abstract: The Scanning Electron Microscope (SEM) has been used to study the adhesion of red oxide primer on selected substrates. The substrates are stainless steel, mild steel, galvanized steel and aluminium. Twenty (20 No) specimens were prepared from the four different substrate metals and examined metallographically, after coating them with red oxide primer using different methods of application. Results showed varying degrees of adherence. The red oxide primer was able to form bonds with the different substrate metals, especially with the well cleaned, primed and subsequently painted stainless steel specimen.

Abstract: In recent years the wind turbine blade has been the subject of comprehensive study and research amongst all other components of the wind turbine. As our appetite for renewable energy from the wind turbine continues to increase, companies now focus on rotor blades which can go up to 80m in length. The blade material not only have to face large aerodynamic, inertial and fatigue loads but are now being designed to endure environmental effects such as Ultraviolet degradation of surface, accumulation of dust particles at sandy locations, ice accretion on blades in cold countries, insect collision on blades and moisture ingress. All this is considered to ensure that the blades complete its designated life span. Furthermore exponential increase in composite blade manufacturing is causing a substantial amount of unrecyclable material. All these issues raise challenges for wind blade material use, its capacity to solve above mentioned problems and also maintain its structural integrity. This paper takes on this challenge by optimizing from the properties, merits, demerits and cost of different possible competing materials. Then the material is checked for its structural integrity through Finite Element Analysis simulation using standards like IEC-61400-1.This paper also shows the future direction of research by elaborating the influence nanotechnology can have in the improvement of the wind blade.

Abstract: Carbon fiber-reinforced polymer (CFRP) material is increasingly being used for the repair of steel structures, mainly because of their superior mechanical properties. However, there is insufficient information on the environmental durability of CFRP-steel bond, especially in hygrothermal aging combined with sustained load. In this paper, 500 mm long І steel beam specimens reinforced with externally bonded wet-laid CFRP sheets are investigated. The specimens are subjected to a sustained four point flexural load of about 30% of initial ultimate load, placed into hygrothermal condition. The ultimate bear capacity and the failure characteristics of the CFRP and steel interface are studied after hydrothermal age and loading. The test results show that the coupled action of sustained load and hygrothermal aging reduces the bond strength of CFRP-steel, even for relatively short conditioning periods, and appears to significantly affect the failure characteristics of specimens.

Abstract: Many modern military aircraft are constructed from composite and bonded structure, such as thin carbon-epoxy laminate bonded to Kevlar® and Nomex® honeycomb. Operation of these platforms in Australian and global conditions will subject the structure to potentially high levels of humidity, extremes in temperature, and for maritime operations, exposure to salt spray conditions. The thin composite laminate is likely to rapidly absorb moisture in a humid environment and enable permeation of moisture into the adhesive and core. In addition to the chemical influence of moisture on the composite structure, the moisture trapped in the honeycomb structure may freeze and expand with changes in altitude during operations or simply due to daily temperature fluctuations at the resident airbase. The combination of moisture ingress in the honeycomb structure and thermal cycling may lead to deteriorated strength of the honeycomb panels over time that would not be observed for long term humid exposure alone. Long term salt water absorption may also have an adverse effect on composites structures. This study investigates the effects of humid environments and thermal cycling on the mechanical properties of composite and honeycomb structures.