In casting industries, issue of spent molding sand disposal is the origin of molding sand reclamation. Among from all reclamation concepts the thermal reclamation method is better for no-bake sand system. This study focuses on the evaluation of sand quality by considering physical and chemical characteristics of molding sand, which is reclaimed by thermal reclamation method. Electric fuel and fluidization mechanism is used in thermal reclamation system. Effect of reclamation temperature, soaking period and sand quantity on % reclamability, grain size, ADV and on LOI is investigated. The average grain size, low ADV, low LOI and acceptable % reclamability of thermally reclaimed sand are studied.
This study aims to predict whether university students will make efficient use of Artificial Intelligence (AI) in the coming years, using a statistical analysis that predicts the outcome of a binary dependent variable (in this case, the efficient use of AI). Several independent variables, such as digital skills management or the use of Chat GPT, are considered.The results obtained allow us to know that inefficient use is linked to the lack of digital skills or age, among other factors, whereas Social Sciences students have the least probability of using Chat GPT efficiently, and the youngest students are the ones who make the worst use of AI.
Forest transition is a trend change process from decreasing to increasing forest area in a country or region. Since the 1990s, ecological and environmental problems such as climate change and loss of biodiversity have received constant attention. The research theory and method of forest transformation has gradually become the frontier and hot topic pursued by international academic circle. With forest transformation as the theme, on the basis of introducing the origin of forest transformation research, along the development vein and internal logic of forest transformation research, this paper reviews the research progress of forest transition theory from the perspectives of Kuznets curve of forest environment and forest transition path, and summarizes the major issues in forest transformation research. The main direction of future research is proposed, including the impact of economic globalization on forest transition, the refinement of research units and the analysis of forest quality transition.
The territorial planning approach to allocating productive forces is based on the fact that territories have competitive advantages in producing specific products. However, in agriculture, the advantages principle cannot be used to shape the allocation patterns, due to a variety of intervening factors, such as the climatic and environmental conditions for agricultural production and the quality of land and availability of water. In the case of Russia, one of the most diverse countries in terms of the territorial disparities in agricultural production, this study examines the location and development patterns of the agricultural sector. The study identifies the competitive advantages of territories by comparing localization of agricultural production, production costs, performance, and profitability of agricultural producers, as well as prices of agricultural products in 78 different administrative regions in Russia. The study reveals which regions have more advantageous conditions for over-concentrating energy capacities, labor resources, fixed capital, and investments. However, at a certain point, over-concentrated production forces can lead to a deterioration in the performance of farmers due to an increase in capital intensity. Therefore, countries with significant regional differences in agricultural production should adjust their spatial development patterns according to the parameters of territories’ comparative advantages.
Although the problems created by exceeding Earth’s carrying capacity are real, a too-small population also creates problems. The convergence of a nation’s population into small areas (i.e., cities) via processes such as urbanization can accelerate the evolution of a more advanced economy by promoting new divisions of labor and the evolution of new industries. The degree to which population density contributes to this evolution remains unclear. To provide insights into whether an optimal “threshold” population exists, we quantified the relationships between population density and economic development using threshold regression model based on the panel data for 295 Chinese cities from 2007 to 2019. We found that when the population density of the whole city (urban and rural areas combined) exceeded 866 km−2, the impact of industrial upgrading on the economy decreased; however, when the population density exceeded 15,131 km−2 in the urban part of the cities, the impact of industrial upgrading increased. Moreover, it appears that different regions in China may have different population density thresholds. Our results provide important insights into urban economic evolution, while also supporting the development of more effective population policies.
Flash flood is one of the major natural hazards in China. It seriously threatens the lives of people and property in mountainous areas. Various methods have been developed for flash flood study, but most of them focused on the past few decades. As one of the effective methods of historical flash flood events reconstruction, dendrogeomorphology has been used worldwide. It can provide hazard information with long temporal scale and high temporal resolution, sometimes at the seasonal level. By comparing tree ring width and other growth characteristics between disturbed and undisturbed trees, growth disturbance signals can be found in the disturbed trees. Using the growth disturbance in tree rings, flash flood events can be dated, and then the frequency, size, and spatial distribution characteristics of flash floods that have no or little documentary records can be reconstructed. The discharge of flash flood can be reconstructed quantitatively according to the height of scars or by using hydraulic models. With the development of dendrogeomorphology, research tends to probe into the meteorological driving mechanism of flash floods and the pattern of flash floods on a larger spatial scale. In the practical application of dendrogeomorphology, more instrumental data and historical records are applied in the studies. This makes the method increasingly more widely used around the world. But work based on dendrogeomorphology has not been reported in China. In this article, we reviewed the development of the study on flash floods based on tree ring, briefly summarized the research progress, and discussed the advantages, limitations, and potential of this approach, so as to provide some reference information for relevant work in China.
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