Thermal silica-based geopolymer composite system: study of processing and mechanical properties

katedra: KMT;V této disertační práci jsou presentovány: 1) vlastnosti dvou geopolymerních systémů na bázi termální siliky spolu s dalšími typy funkčních aditiv 2) vlastnosdti komerčních vyztužujících vláken hodnocených za běžných podínek a to před tepelným namáháním a po tepelném namáhání až do 1000 stupňů CIn this dissertation 1) the properties of two systems of geopolymers based on thermal silica with different functional additives are presented, 2) properties of commercial fibers are evaluated at real conditions before and after heat treatment up to 1000

DEVELOPMENT OF A SIMPLE TECHNOLOGY TO REMOVE ARSENIC IN GROUND WATER BASED ON USING "LATERITE"-ADSORBENT, A COMMON NATURAL IRON ORE IN VIETNAM

Joint Research on Environmental Science and Technology for the Eart

Water-Assisted Oxygen Activation During Selective Oxidation Reactions

The selective functionalization of hydrocarbons with oxygen to produce valuable commodity chemicals is inherently challenging, because of the thermodynamic stability of the complete combustion products. Emerging green synthesis routes and sustainable energy production also rely on the success of selective oxidation reactions. As one of the unselective by-products, water is always present under reaction conditions and numerous studies indicate that the catalytic activity and selectivity of selective oxidation reactions may be tuned by judiciously controlling the water content during the reaction. Some experimentally verified examples include the preferential oxidation of carbon monoxide, direct hydrogen peroxide synthesis, propene epoxidation and alcohol oxidation. Finally, it has been predicted that the direct conversion of methane to methanol can benefit from the right amount of water near the active site during oxygen activation

Tax corruption and private sector development in Vietnam

This article aims to examine the impact of tax corruption on private sector development in Vietnam. It is motivated by two separate but related considerations. First, despite the seriousness of the phenomenon of corruption, there is a paucity of rigorous empirical research of corruption, particularly tax corruption, in Vietnam. Secondly, ineffective control of corruption is viewed as a cause of Vietnam’s recent total factor productivity (TFP) slowdown or its poor industrial policy, both of which may hamper Vietnam’s progress as a low middle-income country. Without some understanding on the impact of tax corruption on the economy, it may not be possible to devise the most effective anti-corruption policy and measures. After a brief literature review that focuses on tax corruption, various conceptual issues relating to tax corruption are discussed and clarified. The extent of petty tax corruption in Vietnam is then discussed, followed by a review of findings and implications of recent studies on how tax corruption impacts on private sector development in Vietnam. Despite perceptions and evidence of widespread petty tax corruption, Vietnam ranks very highly both in terms of tax collection and tax effort.Not unexpectedly, the impact of tax corruption is mixed in the sense that empirical evidence lends credence to both 'sanding the wheels' and 'greasing the wheels' hypotheses. Finally, some broad policy recommendations for combating tax corruption are offered

Pro-poor intervention strategies in irrigated agriculture in Asia: poverty in irrigated agriculture: issues and options: Vietnam

Irrigated farming / Poverty / Farm income / Irrigation management / Institutions / Legal aspects / Water rates / User charges / Participatory management / Privatization / Participatory rural appraisal / Performance indexes / Irrigation programs / Irrigation systems / Pumping / Irrigation canals / Social aspects / Economic aspects / Rivers / Hydrology / Dams / Households / Income / Regression analysis / Drainage / Cooperatives / Water delivery / Water distribution / Rice / Financing / Drought / Vietnam / Red River Delta / Nam Duong Irrigation System / Nam Thach Han Irrigation System / Han River

The Social Vulnerability index as a Risk Stratification tool For Health Disparity Research in Cancer Patients: a Scoping Review

PURPOSE: The social vulnerability index (SVI), developed by the Centers for Disease Control and Prevention, is a novel composite measure encompassing multiple variables that correspond to key social determinants of health. The objective of this review was to investigate innovative applications of the SVI to oncology research and to employ the framework of the cancer care continuum to elucidate further research opportunities. METHODS: A systematic search for relevant articles was performed in five databases from inception to 13 May 2022. Included studies applied the SVI to analyze outcomes in cancer patients. Study characteristics, patent populations, data sources, and outcomes were extracted from each article. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: In total, 31 studies were included. Along the cancer care continuum, five applied the SVI to examine geographic disparities in potentially cancer-causing exposures; seven in cancer diagnosis; fourteen in cancer treatment; nine in treatment recovery; one in survivorship care; and two in end-of-life care. Fifteen examined disparities in mortality. CONCLUSION: In highlighting place-based disparities in patient outcomes, the SVI represents a promising tool for future oncology research. As a reliable geocoded dataset, the SVI may inform the development and implementation of targeted interventions to prevent cancer morbidity and mortality at the neighborhood level

A Very Wideband Circularly Polarized Crossed Straight Dipole Antenna with Cavity Reflector and Single Parasitic Element

A very wideband circularly polarized (CP) crossed dipole antenna is presented in this paper. The primary radiating element of the antenna consists of two straight dipoles arranged orthogonally through double printed rings. To further enhance the axial ratio bandwidth, a cavity with proper size and single parasitic element are employed to generate two additional bands. The use of cavity reflector is investigated thoroughly, providing a solid framework for designing this type of antennas. The final design with an overall size of 0.92λo × 0.92λo × 0.32λo at the center CP frequency yields a measured –10 dB-impedance bandwidth of 75.2% and 3 dB-axial ratio bandwidth of 67.7%. The proposed antenna exhibits right-handed circular polarization and an average broadside gain of about 8.3 dBi over the CP operating bandwidth

The impact of petty corruption on firm innovation in Vietnam

Corruption has been found to have complex effects on firm innovation.Limited theoretical and empirical evidence to date has been rather inconclusive. This study employs econometric estimation techniques to analyze data from small and medium manufacturing enterprises in Vietnam to assess the impact of petty corruption on firm innovation. The empirical results tend to support the "greasing" impact of corruption on innovation. Specifically, informal payments by Vietnamese firms are shown to encourage overall innovation, product improvement, innovation and new innovation. In view of the commonplace business practice of paying small informal fees to speed up transactions in the inefficient public sector in Vietnam, this finding is not entirely unexpected, though troubling