Mahidol University's Institutional Repository
คลังสารสนเทศสถาบันของมหาวิทยาลัยมหิดล
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To collect Mahidol University's academic publications and intellectual properties more than 39 faculties
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Recent Submissions
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Gender Disparities in Digital Employment in China
(2024-12-01) Mi H.; Tey N.P.; Lai S.L.; Mi H.; Mahidol University
The rapid expansion of the digital economy has profoundly reshaped employment dynamics in China. Drawing on microdata from the China General Social Surveys (CGSS) conducted in 2010 and 2021, this study delves into the evolving gender gap within China’s digital workforce. Through bivariate analyses and logistic regression, this research examines how gender intersects with various factors, including age, educational attainment, account status, number of children, internet usage, and geographical region, to elucidate disparities in digital employment. Findings indicate a shift towards greater gender parity in the digital sector, notwithstanding enduring challenges for women. The responsibilities of childbearing and childrearing have constrained women’s engagement in digital occupations, although this impediment is diminishing. Educational achievements and internet usage emerge as pivotal determinants of digital employment for both genders. Workers in the more developed Eastern region exhibited higher likelihoods of digital employment than those in other regions. Diverse strategies are essential to tackle gender gaps in digital employment.
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Depressurization-induced production of shale gas in organic-inorganic shale nanopores: A kinetic Monte Carlo simulation
(2024-11-01) Tun H.M.; Chinkanjanarot S.; Srinives S.; Jonglertjunya W.; Klomkliang N.; Phadungbut P.; Tun H.M.; Mahidol University
Methane gas production from unconventional reservoirs, such as shale formations, is in high demand due to the global energy needs. However, maximizing production remains challenging due to the ultra-tight porosity, heterogeneity, and complex nature of shale rocks under high pressure. To address this issue, we employ a novel kinetic Monte Carlo (kMC) simulation to investigate the molecular-level behavior of shale gas in both homogeneous and heterogeneous organic-inorganic shale nanopores. This approach not only provides accurate computations of shale gas under high pressure but also aims to uncover the mechanisms of shale gas storage at reservoir pressure and production during pressure drawdown. Our findings indicate that organic shale ultramicropores (pore width < 0.7 nm) contribute significantly to the highest storage capacity of shale gas but pose challenges for production capacity solely through depressurization. In contrast, the free gas zone is the primary source of shale gas production from mesoporous shales, which has a high recovery efficiency but a low production capacity due to less pronounced interaction effects from the shale surface. The heterogeneous nature of shale surfaces leads to asymmetric distributions of density and potential energy across pore widths, with methane molecules favoring locations near organic pore walls due to stronger attractive interactions, while inorganic pore walls facilitate shale gas migration. Interestingly, the optimal ultramicropore size yields the highest recovery efficiency of shale gas via depressurization, characterized by a transition from near-commensurate to incommensurate molecular packing between reservoir and post-drawdown pressures. Based on these detailed molecular simulations, further research is necessary to develop innovative techniques for enhancing shale gas recovery, especially in micropores.
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Catalytic Deoxygenation of Palm Oil Over Iron Phosphide Supported on Nanoporous Carbon Derived from Vinasse Waste for Green Diesel Production
(2024-01-01) Nenyoo P.; Wongsurakul P.; Kiatkittipong W.; Kaewtrakulchai N.; Srifa A.; Eiad-Ua A.; Assabumrungrat S.; Nenyoo P.; Mahidol University
The vinasse waste was effectively converted to nanoporous carbon (NPC) via hydrothermal carbonization with potassium hydroxide (KOH) activation. The nanoporous carbon (NPC) exhibited a maximum surface area of 1018 m2/g and it was utilized as a catalyst for the conversion of palm oil into green diesel fuel. The supported NPC catalyst was fabricated via a wet impregnation technique, where finely distributed iron phosphide (FeP) particles were cemented. The FeP/NPC catalyst was evaluated for its physicochemical characteristics using various techniques including X-ray diffraction (XRD), nitrogen sorption analyzer, transmission electron microscopy (TEM), and energy dispersive X-ray spectrometry (EDS) mapping. An investigation was conducted to examine the effects of different temperatures (ranging from 280 to 360 °C) on the conversion of palm oil through deoxygenation reactions. The FeP/NPC catalyst exhibited remarkable particle dispersion and surface area. At a reaction temperature of 340 °C, the FeP/NPC catalyst had the best selectivity for green diesel, reaching 68.5%. The finding implies that FeP catalysts, when supported, hold significant promise for converting triglycerides into renewable diesel fuel. Moreover, they provide the advantage of being more cost-effective than valuable metals, while demonstrating excellent catalytic efficiency in the production of biofuels. Furthermore, it has been shown that the FeP/NPC catalyst can be recycled by subjecting it to heat treatment to remove impurities and obtain reduction.
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Fire Impacts on Soil Properties and Implications for Sustainability in Rotational Shifting Cultivation: A Review
(2024-09-01) Arunrat N.; Kongsurakan P.; Solomon L.W.; Sereenonchai S.; Arunrat N.; Mahidol University
Fire, a prevalent land management tool in rotational shifting cultivation (RSC), has long been debated for its immediate disruption of surface soil, vegetation, and microbial communities. While low-intensity and short-duration slash-and-burn techniques are considered beneficial for overall soil function, the dual nature of fire’s impact warrants a comprehensive exploration. This review examines both the beneficial and detrimental effects of fire on soil properties within the context of RSC. We highlight that research on soil microbial composition, carbon, and nitrogen dynamics following fire events in RSC is gaining momentum. After fires, soil typically shows decreases in porosity, clay content, aggregation, and cation exchange capacity, while sand content, pH, available phosphorus, and organic nitrogen tend to increase. There remains ongoing debate regarding the effects on bulk density, silt content, electrical conductivity, organic carbon, total nitrogen, and exchangeable ions (K+, Ca2+, Mg2+). Certain bacterial diversity often increases, while fungal communities tend to decline during post-fire recovery, influenced by the soil chemical properties. Soil erosion is a major concern because fire-altered soil structures heighten erosion risks, underscoring the need for sustainable post-fire soil management strategies. Future research directions are proposed, including the use of advanced technologies like remote sensing, UAVs, and soil sensors to monitor fire impacts, as well as socio-economic studies to balance traditional practices with modern sustainability goals. This review aims to inform sustainable land management practices that balance agricultural productivity with ecological health in RSC systems.
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The Physical Properties of Vanillin-Incorporated Irreversible Hydrocolloid Impression Material
(2024-01-01) Leelapong S.; Mateekusontan S.; Makkrajang S.; Churnjittapirom P.; Thaweboon S.; Leelapong S.; Mahidol University
Irreversible hydrocolloid impression material is extensively used in dentistry to record and duplicate the details of tooth structure, surrounding tissue, and other intraoral structures. The materials allow dentists to work more easily and perform better diagnosis and treatment planning. When used, the material is exposed to oral micro organisms, some are pathogens, from the patient’s teeth, mucosa, blood, and saliva. These pathogens can be absorbed into the material and transmitted to dentists and other dental workers. Hydrocolloid impression material incorporated with vanillin has been shown to exhibit antimicrobial potential, however, its physical properties have not been performed. Therefore, this study aims to investigate the physical properties of a vanillin-in corporatedir reversible hydrocolloid impression material on four different physical properties: working time, setting time, elastic recovery, and strain-in compression. The impression powder was mixed with varying concentrations of vanillin (0.1%, 0.5%, and 1.0% w/w) using the electric vacuum mixer. The impression material without vanillin was used as a control. All the tests were done following the ISO specification 21563: 2021 for dental materials with 15 specimens for each test. The result showed that at concentrations of 0%, 0.1%, and 0.5% w/w vanillin, no significant change in the four physical properties has been observed. However, the working time and setting time values of impression material with 1% vanillin were reduced significantly and did not meet the ISO standard. In conclusion, the incorporation of 0.1%, 0.5%, and 1% w/w vanillin into irreversible hydro colloid impression material showed a significant reduction in setting time and working time. However, when considering the ISO standard specifications, the 0.1% and 0.5% w/w vanillin-added materials can stillbe used due to their acceptable values of all physical properties (setting time, working time, elastic recovery, and strain-in compression). These impression materials will be valuable for use in clinical settings to reduce the disinfection procedure and the risk of cross-contamination.