Papers by Keyword: Migration

Abstract: To protect the underlying soil and groundwater from landfills, the landfills are commonly lined with layered liner systems. Geosynthetic clay liners (GCL) have been increasingly used in the landfill liner systems to substitude the traditional compacted clay liners (CCL) because of their low cost, easily construction behavior and low leakage rate. To study the behavior of the GM+GCL liner system used in China due to the migration of Pb²⁺, we introduce in detail GM+GCL liner systems proposed by the Chinese specification. Then one dimensional finite layer model is used to investigate the anti-pollution behavior of the CM+GCL composite liner systems, with the focuses on the heavy metal Pb²⁺. It could be concluded that the main migration way through the GM+GCL composite liner system is that the transport of Pb²⁺ through a GM+GCL composite liner system of a landfill cover takes place primarily through the holes in the GM. The findings provide useful reference for preventing, controlling and treating groundwater pollution in the GM+GCL liner system technically and scientifically.

Abstract: An analytical model is established to predict the seepage performance of the liner system composed of a compacted clay liner (CCL) covered by a geomembrane (GM). The contaminant of Pb²⁺ diffusing through the geomembrane is assumed to be a steady-state process. The liner systems with low leakage performance are usually utilized in the municipal solid waste landfills to prevent the contaminants of the leachate from polluting the groundwater and soil beneath the landfill. To investigate the seepage rate of the Pb²⁺ in the liner systems of the landfill considering the effects of the geomembrance, the influence of the geomembrance on the seepage performance of the liner system is studied. Parametric analyses are conducted to study the effects of the thickness of GM and the number of defects in the GM on the leakage performance of the liner system. In conclusion, some suggestions for the design of the municipal solid waste landfills are proposed based on the analyses results.

Abstract: Nowadays the use of biodegradable plastic in the food industry has increased dramatically. Because of its outstanding characteristics, i.e. environmental friendliness and non-toxicity, researchers are interested in studying how to improve the properties of plastic, especially polylactic acid or PLA, which is very fragile and intolerant to high impact force. Attempts have been made to improve the weak points of PLA by mixing PLA with epoxidized natural rubber. The natural rubber goes through an epoxidation process, resulting in epoxidized natural rubber (ENR) as the finished product. ENR contains epoxy groups which can efficiently react with PLA. Ratios of PLA and ENR employed in this study were 50:50, 60:40, 70:30, 80:20 and 90:10. In addition to finding a suitable ratio between PLA and ENR, the mixtures were subjected to migration tests according to the guidelines specified in European Commission Regulation (EU) No 10/2011 in order to prove whether the mixed materials are safe and suitable for consumer use. Migration testing was conducted by soaking samples in four different food simulants – 10% (v/v) ethanol in aqueous solution, 3% (w/v) acetic acid in aqueous solution, 20% (v/v) ethanol in aqueous solution and vegetable oil – for 24 h at 40 °C. The results showed that the PLA/ENR blends at every ratio had an overall migration amount of less than 10 mg/dm² in three of the sample simulants, while the overall migration from materials soaked in vegetable oil exceeded this standard. Migration tests of one of the sample blends conducted at 100 °C for 2 h showed similar results. In conclusion, polymer blends of PLA and ENR are appropriate for food packaging applications, but are not appropriate for foods containing vegetable oil.

Abstract: The structure of the starch/styrene-butadiene latex composites was characterized using Scanning Electron Microscopy (SEM). In order to get a better contrast between starch and latex, OsO₄ were used to stain latex. Ion-beam cutting and liquid nitrogen cracking were employed to fabricate qualified cross-sections for SEM characterization. During drying, starch and latex migrate, creating non-uniform structure with latex dominated in the lower surface (next to the substrate) and starch in the upper surface (open to the air). The film formation of latex is slower than the starch/latex film forming. Phase separation occurs with starch granules embedded in the latex-starch matrix, reinforcing the composites. The analysis of composite structure and use of Perera approach indicate that good adhesion is present between latex phase and starch phase, starch granules and latex-starch matrix. When the latex is substituted by starch, the elastic modulus and tensile strength increase whilst the elongation at break decreases. When the volume fraction of starch is higher than 41.7 %, increasing starch content, the increase of ultimate tensile strength and elastic modulus accelerate, whereas the elongation at break decreases slower, which may arise from the phase co-continuity of starch.

Abstract: Cloud computing is a platform that provides different services for the Internet users and companies on a pay-as-you-use basis. Services are provided through the datacenters which are available all over the world. One of the major problems faced by the service providers is the huge amount of energy consumed at the Datacenter. In todays world, where the environmental factors are the most talked about, energy efficient management of Datacenters has to be given due importance. In this paper a migration model is proposed for migration of job between virtual machines by considering the energy consumed and deadline as crucial factors.

Abstract: As an important part of food safety, the safety of food packaging receives increasingly attention from public. Some chemicals in the food container or packaging would migration after contacting with food for a long time. We analyze three classical plasticizer migration models in China, and give contrast analysis. Then we measured the antioxidants migration status under different circumstances, getting the original experimental data. In addition, we adopt the best experiment scheme among the three methods, measuring the migration of antioxidants in different situations and obtain migration curves.

Abstract: Instant messaging technologies are becoming more and more mature as network gains popularity and develops rapidly. Instant messaging software such as QQ and Wechat from Tencent, Mitalk and YY Voice are based on C/S mode. In this paper, after completing software development, the platform is migrated and its kernel recompiled. After building root file system and migrating relevant library files, it not only resolves the problems such as Chi-nese gibberish and missing input method after migration, but also designs an instant messaging software for enterprises similar to IP messenger through P2P technology and C++ pro-gramming in QT framework based on Socket communication mechanism, thus realizing messaging and file transfer within LAN.

Abstract: T wisted yarns are used for bio-composites and nanocomposites as reinforcement . In a twisted yarn, single yarns migrate from surface to inner along the yarn axis. In this research , migration structure is studied by using X-ray CT system . The result is obtained that the orientation angle correlates with layer .

Abstract: Juglone is isolated from many plant species belonging to Juglandaceae family. Recent studies have shown that Juglone exhibits various bioactivities including anti-tumor functions. However, its anti-cancer activity on human ovarian cancer SKOV3 cell has not been examined. Thus, the current study was designed to elucidate the effect of Juglone on migration of human ovarian cancer SKOV3 cells. In the present study, SKOV3 cells were incubated with Juglone at various concentrations. Wound healing assay and Transwell chambers were used to detect migration of SKOV3 treated with Juglone for 24h. The result showed that Juglone inhibited the migration of SKOV3 cells with concentration of Juglone at 25, 50 or 100μM compared with control cells. Therefore, our results indicated that Juglone may be a potential candidate of drug for ovarian cancer.

Abstract: Organochlorine pesticides (OCPs), which is widely distributed in the environment, long residual period, semi volatile, high toxicity of persistent organic pollutants (pops), can migrate for long distances through a variety of environmental medias. In this study, we introduced the OCPs on the ways of pollution in the environmental soil and its characteristics of residues. We discussed the migration and transformation of OCPs in the environmental soil.