No abstract

No abstract

The utilization of clays to enhance the water vapour barrier properties of polyethylene requires knowledge about factors associated with the constituents themselves. Hence, this paper presents combinations of two types of polyethylene and five different clays. Morphological, mechanical and thermal properties related to the water vapour permeability of clay/polyethylene composites were investigated. Although no evidence of clay exfoliation was observed according to morphological and spectral results, it was found that the enhanced water vapour barrier properties were linked to clay aspect ratio, composites interface, polyethylene crystallinity and storage conditions. The best water vapour barrier properties were obtained by increasing polyethylene crystallinity with unmodified clay of high aspect ratio. Organoclays addition showed no improvement in barrier properties of polyethylene unless the interface was strongly compatibilized. Contrary to the results published elsewhere, clay addition brought about no mechanical improvements to polyethylene tested.

The Kanto region is an earthquake disaster-prone area where it is necessary to conduct regional seismic hazard analysis. Ground-motion models (GMMs) of Arias intensity, cumulative absolute velocity, and significant duration are developed by support vector regression (SVR) for the Kanto region, Japan. In contrast to traditional regression programs used in previous models, which are usually expressed as a mathematical function with a minimum observed training error as constraints, the SVR algorithm has one major feature: it minimizes the generalized error bound to improve robustness. In the database for this study, the regional ground-motion database contains 15,960 ground-motion records of 130 earthquake events from 2000 to 2020 with the Japan Meteorological Agency (JMA) with a magnitude MJMA 5.0–8.0 and a rupture distance less than 200 km. In developing SVR GMMs, the moment magnitude (Mw), rupture distance (Rrup), and shear-wave velocity averaged in the top 30 m of soil (VS30) were adopted to characterize the source, path, and site conditions. To verify the rationality and effectiveness of the SVR GMMs, the performance indices (e.g., correlation coefficients and slope coefficients) and residuals are analyzed. The residuals of the SVR GMMs have no significant deviation in magnitude, rupture distance, or VS30. The standard deviations of model residuals are calculated using the regional ground-motion database, and the standard deviations of SVR GMMs are less than those of previous models developed based on a Japanese or global database. Furthermore, the SVR GMMs are also compared with observed data and the previous GMMs. Data-driven SVR method constrains statistical theory and probability theory to develop GMMs, which can eliminate the problem that the specific form of the previous models may affect the prediction performance and capture the regional attenuation characteristics effectively.

Tourism is playing an important role in the economic development of the Qinghai-Tibet Plateau (QTP). To better develop tourism in this region, the spatial heterogeneity of influencing factors on tourism needs to be studied. Using the spatial distribution of tourism potential from social media data, this paper analyzes the influencing factors of tourism on the QTP from the perspective of spatial heterogeneity. We extract microblogs related to travel topics connected to the QTP in 2017 from Sina Weibo to capture tourism potential. Then, factors considered from six aspects (tourism resources, amenities, transportation, geography, population, and the economy) are selected, and a geographic detector (Geodetector) is employed to detect the explanatory power of these factors for tourism potential. The results indicate different influential tourism factors in Qinghai and Tibet. In Qinghai, the main factors are hotels, tourist attractions, and road network density, and the explanatory power of the factors mainly comes from eastern and western Qinghai. In Tibet, the main factors are road network density, regional GDP (Gross Domestic Product), and urban land. It is suggested that tourism in the central region of Qinghai can be improved by enhancing the publicity and utilization of tourism resources, and Tibet should enhance tourism resource utilization and improve tourism amenities and infrastructure.