Experimental investigation of heterogeneously catalyzed hydrolysis of esters

Thermodynamics, equilibirum, reaction kinetics, heterogeneous, hydrolysis, ion-exchange resin, calorimetryMagdeburg, Univ., Fak. für Verfahrens- und Systemtechnik, Diss., 2006von Thanh-Phong MaiZsfassung in dt. Sprach

Development of Questionnaire on Supplier Selection Criteria for Textile and Apparel Industry – A Case Study in Vietnam

Supplier selection criteria are of importance in supplier selection because of their impact on the input materials and production progress of purchasers. However, there is a dearth of researches on a well-designed and validated questionnaire to assess supplier selection criteria for textile and apparel sector in general and for Vietnamese textile and apparel industry in particular. Therefore, the purpose of this study was to develop a questionnaire to assess those criteria with their level of importance. An integrated approach of qualitative and quantitative was employed in the study. First, the qualitative approach involving purposeful sampling and theoretical sampling was used to explore what supplier selection criteria Vietnamese textile and apparel companies were utilizing after the literature on supplier selection criteria had been reviewed. Next, a prequestionnaire was built and sent to some practitioners and experts for their revision. Then, a pilot survey of 31 companies was conducted in Vietnamese textile and apparel companies to determine the supplier selection criteria that are best suited for Vietnamese textile and apparel companies. Numerous statistical tests were conducted to validate the results which will be a good contribution to the selection process of textile and apparel companies, especially Vietnamese companies. They can utilize the questionnaire as a tool to set their supplier selection criteria

CHẾ TẠO VÀ ỨNG DỤNG HỆ THỐNG THIẾT BỊ SẤY CÀ PHÊ SỬ DỤNG KẾT HỢP NĂNG LƯỢNG MẶT TRỜI VÀ SINH KHỐI

Bên  cạnh  các  nguồn  năng  lượng  sạch  như  năng  lượng  gió,  thủy  triều,  địa  nhiệt…,  năng lượng mặt trời là nguồn năng lượng phổ biến và dễ được ứng dụng trong một số lĩnh vực. Tuy nhiên, việc lưu trữ và dùng năng lượng mặt trời kết hợp năng lượng từ nguồn sinh khối để làm nóng tác nhân sấy trong các thiết bị sấy là hoàn toàn mới. Vấn đề gặp phải trong phương án này là làm sao tích trữ được nhiệt năng của mặt trời, từ đó tải nhiệt cho tác nhân sấy. Đặc biệt, việc kết hợp và tối ứu hóa việc sử dụng năng lượng mặt trời và năng lượng từ việc đốt nhiên liệu có nguồn gốc sinh khối nhằm đảm bảo tính hoạt động liên tục của thiết bị khi thời tiết thay đổi là vấn đề cần phải giải quyết trong nghiên cứu này. Công trình đã nghiên cứu, chế tạo thành công hệ thống thiết bị sấy cà phê sử dụng kết hợp năng lượng mặt trời và sinh khối, đảm bảo các tính năng nêu trên. Kết quả sấy thử nghiệm cà phê trên hệ thống thiết bị cũng được trình bày trong bài báo này

Gasification of Biomass

Gasification is an indirect combustion of solid and liquid biomass by converting them to combustive syngas. Gasification is an alternative process for the traditional combustion, in which the emission of dust and toxic gases can be minimized. In this chapter, a comparison of these two biomass-to-heat conversion processes applied on biomass is presented in term of environmental impacts and technological benefits with a hope to provide readers a basic view of choices. Gasification is classified as in term of gasification agents, non-catalytic and catalytic process, and plasma assisted process. Popular types of gasification equipment, aka gasifiers, are introduced with working principles, through which the advantages and weakness of technology are briefly discussed

MODIFICATION OF POLYSULFONE ULTRAFILTRATION MEMBRANES WITH PVA AND TiO2 FOR BETTER ANTIFOULING

The objective of this study was to investigate anti-fouling property of modified polysulfone ultrafiltration  (UF) membranes.  Polysulfone UF membranes were modified  by  coating  a  thin film of polyvinyl alcohol (PVA), or a mixture of polyvinyl alcohol and titanium dioxide (TiO2) on  surface.  Effects  of  curing  temperature  on  the  coated  membranes  were  also  studied.  The modified  membranes  were  tested  with  0.5  g/L  sodium  alginate  solution  and  industrial  dye wastewater.  Curing  temperature  influenced  remarkably  flux  and  fouling  property  of  the membranes. Among experiments studied, 85 oC was the best curing temperature. The PVA and PVA/TiO2-coated membranes reduced fouling significantly. Dispersion of TiO2 nanoparticles on membrane surface improved considerably bacteria removal of the membranes

Bioethanol Production from Lignocellulosic Biomass

An overview of the basic technology to produce bioethanol from lignocellulosic biomass is presented in this context. The conventional process includes two main steps. First, lignocellulose must be pretreated in order to remove lignin and enhance the penetration of hydrolysis agents without chemically destruction of cellulose and hemicellulose. Second, the pretreated material is converted to bioethanol by hydrolysis and fermentation. Some typical published studies and popular processing methods in attempts to improve the biomass conversion to bioethanol and increase the cost-effectiveness are also introduced briefly. Herein, the refinery of the resulted raw bioethanol mixture to obtain higher concentrated solution is not regarded

EVALUATION OF STERCULIA FOETIDA L. GUM AS NATURAL BASED CONTROLLED RELEASE EXCIPIENT

Therefore, the physicochemical properties of Sterculia foetida L. gum, including solubility, scanning electron micrographs, melting point, swelling index, pH, viscosity, loss on drying were determined. Furthermore, compressed tablets were successfully prepared for in vitro studies at many different particle sizes, concentrations of gum, rotational speeds and media in order to evaluate the effects of these parameters on the rate of drug release. Besides, SFG tablets were compared with the tablets prepared with Hydroxymethylcellulose E15. The findings indicated that Sterculia foetida L. gum exhibited an excellent potential in managed release dosage forms.

Modeling quality of life of Ho Chi Minh City dwellers

Quality of life (QoL) has received more and more attention from scholars and researchers from various fields such as healthcare, philosophy, psychology, sociology, and especially economics after many decades of focusing on income. However, researchers have faced many challenges to gain the proper measurement of QoL due to the contextually based concept. This study employs the primary data conducted in Ho Chi Minh City including 500 observations in 2022, with the application of partial least squares structural equation modeling (PLS-SEM) to construct a hierarchical model to measure the QoL of the dwellers in Ho Chi Minh City. The empirical model supports the multi-level hierarchical structure of the QoL. The statistically significant contribution of economic, social, and environmental dimensions in the integrated index has been confirmed. The environmental component shares the highest weight, followed by the economic factor. The social aspect contributes the least share in the quality- of-life index. Further analysis of the sub-criteria in each dimension has been made. The findings implicitly suggest the policy concentration on sustainable factors enhancement to raise the QoL. It was a milestone for policy makers to switch the focus from material to non-material factors in the life quality model in Vietnam

Synthesis and Characterization of Silver Nanoplates by a Seed-mediated Method

Silver nanoplates (SNPs) having different size were synthesized by a seed-mediated method. The seeds -silver nanoparticles with 4 – 6 nm diameters were synthesized first by reducing silver nitrate with sodium borohydride in the present of Trisodium Citrate and Hydrogen peroxide. Then these seeds were developed by continue reducing Ag$^+$ ions with various amount of L-Ascorbic acid to form SNPs. Our analysis showed that the concentratrion of L-Ascorbic acid, a secondary reducing agent, played an important role to form SNPs. In addition, the size and in-plane dipole plasmon resonance wavelenght of silver nanoplates were increased when the concentration of added silver nitrate increased. The characterization of SNPs were studied by UV-Vis, FE-SEM, EDS and TEM methods