http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Biodiesel Production From Fat of Tra Catfish and Basa Catfish (Viet Nam) Using Alkaline Catalysts
Huong, Le Thi Thanh,Tan, Phan Minh,Hoa, Tran Thi Viet,Lee, Soo The Korean Society of Applied Science and Technolo 2008 한국응용과학기술학회지 Vol.25 No.3
The fat of Tra and Basa catfish (Mekong Delta, Viet Nam) was evaluated for the first time as the potential feedstock for biodiesel production, due to its abundance, availability and cheap cost. The unsaturated fatty acid contents of Tra and Basa fat were 57.97% and 64.17%, respectively. Biodiesel was prepared from Tra and Basa fat by methanolysis reaction using alkali catalysts like sodium hydroxide and potassium hydroxide. Effects of various process parameters on biodiesel production, such as molar ratio of methanol to fat, catalyst concentration, temperature and time were investigated. As those results, the transesterification can be performed under moderate conditions, and the biodiesel yields were shown more than 90%. KOH catalyst was the best catalyst for biodiesel production from both Basa and Tra fat. As the feedstock aspect, Basa fat was indicated more efficiency than that of Tra fat. The maximum yield could be achieved by the transesterification from Basa fat with 5:1 molar ratio of methanol to fat, 0.8% KOH catalyst, $50^{\circ}C$, and 50 min. For Tra fat, the optimal condition were at 6:1 molar ratio of methanol to fat, 0.8% KOH catalyst, $50^{\circ}C$, and 45 min. Nowadays, due to cheaper cost and abundance, Tra fat is a promised resource for cheap biodiesel production in Viet Nam.
Determinants Influencing Management Competency of Small and Medium Enterprise Directors in Vietnam
Thi Mai Huong DOAN,Minh Thuy DO,Thanh Lan MAI,Vu Phuong Anh DO,Thi Loan NGUYEN 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.12
Currently, small and medium-sized enterprises (SMEs) are accounting for about 98% of the total number of enterprises in Vietnam. Each year, SMEs create over one million new jobs, utilize up to 51% of the labor force in the society, and contribute more than 40% of GDP to the country. The study aims to analyze factors affecting the management competency of directors in small and medium enterprises in Vietnam. To achieve these research objectives, quantitative and qualitative methods were used concurrently. 300 questionnaires were sent out, but only 276 were collected and used for the quantitative analysis through SPSS 20.0 software. Cronbach’s Alpha, EFA, and regression were used to further confirm the research findings. The research findings show that all four proposed factors have impacts on the management competency of SME directors, among which enterprise features and specific policies for entrepreneur development in the locality have the strongest impacts, followed by personal features and business environment. The findings of this study suggest that managers need to focus on factors affecting the management competency of directors. This paper also provides new insight into the management competency of directors. Based on the findings, some recommendations are given for SMEs to improve management competency.
Kinetics of the KOH Catalyzed-Methanolysis for Biodiesel Production from Fat of Tra Catfish
Huong, Le Thi Thanh,Tan, Phan Minh,Hoa, Tran Thi Viet,Lee, Soo The Korean Society of Applied Science and Technolo 2008 한국응용과학기술학회지 Vol.25 No.4
Transesterification of fat of Tra catfish with methanol in the presence of the KOH catalyst yields fatty acid methyl esters (FAME) and glycerol (GL). The effects of the reaction temperature and reaction time on rate constants and kinetic order were investigated. Three regions were observed. In the initial stage, the immiscibility of the Tra fat and methanol limited the reaction rate, hence this region was controlled by the mass transfer. Subsequent to this region, produced FAME like a co-solvent made the reaction mixture homogeneous, therefore the conversion rate increased rapidly so it was controlled by the kinetic parameters of the reaction until the equilibrium was approached in the final slow region. A second-order kinetic mechanism was proposed involving second regions for the forward reaction. The rate determining step for the overall KOH catalyzed-methanolysis of Tra fat was the conversion of triglycerides (TG) to diglycerides (DG). This rate constant was increased from 0.003 to $0.019min^{-1}$ when the reaction temperature was increased from 35 to $60^{\circ}C$. Its calculated activation energy was 14.379 ($kcal.mol^{-1}$).
Minh PHAM,Thao Yen DANG,Thi Hong Yen HOANG,Thi Thanh Nga TRAN,Thi Huong Quynh NGO 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.11
The purpose of this study is to understand the impact of influencers on generation Z (Gen Z) in the online environment. This article has applied the theories of source credibility, TAM, IAM, and TPB to identify influencer characteristics that affect the purchasing behaviors of Gen Z customers. This research was conducted using a Google Form survey with 24 pre-designed questions. A total of 464 valid questionnaires from Gen Z Vietnamese were collected between November 2020 and January 2021. Data was analyzed using partial least squares structural equation modeling (PLS-SEM) with SmartPLS 3 software. The analysis results confirmed that the components of influencer credibility have a positive impact on Gen Z’s purchasing behaviors under the mediated influence of argument quality, perceived usefulness, and social influence. Surprisingly, for Gen Z, the influencers’ attractiveness has the strongest impact on their online behavior. More specifically, attractiveness plays the most important role in the perceived usefulness and social influence of Gen Z customers, while influencers’ expertise has the strongest impact on argument quality delivered to customers. This study provides evidence of a change in the way Gen Z responds to marketing activities. They are more drawn by the attraction of influencers than their expertise.
Biodiesel Refining and Glycerin Recovering Process of Transesterification from Tra Catfish Fat
Huong, Le Thi Thanh,Tan, Phan Minh,Hoa, Tran Thi Viet,Lee, Soo The Korean Society of Applied Science and Technolo 2009 한국응용과학기술학회지 Vol.26 No.1
Nowadays, Tra catfish fat is given attention as an appropriate material for biodiesel production in Vietnam. The aim of this work is to investigate the optimal conditions of refining biodiesel and recovering glycerin by the transesterification from Tra catfish fat using KOH catalyst. As our results, the yield of transesterification was achieved to 94.17% at $50^{\circ}C$ for 45 min with 6:1 molar ratio of methanol to fat in the presence of 0.8% KOH catalyst, and wherein the biodiesel was refined by washing with distilled water at $70^{\circ}C$ and dried in a microwave oven. The yield of raw glycerin recoveries from the transesterification process was 78.58%. The purity of raw glycerin was 84.14% by the conditions of neutralization state with $H_{3}PO_{4}$ solution (pH = 5), $70^{\circ}C$, and 60 min. Activated carbon (3.0 wt.%) was used for the bleaching process at $80^{\circ}C$ for 20 min. The biodiesel was obtained in accordance with for ASTM D 6751 (biodiesel standard). The ash and water of raw glycerins were 7.32 and 8.01%, respectively, and implied that the raw glycerin is very promising candidate to be used as a raw material for textile and cosmetic industries.
NGUYEN, Thi Minh Thu,NGUYEN, Thi Tuong Anh,NGUYEN, Thi Thuy Vinh,PHAM, Huong Giang Korea Distribution Science Association 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.3
Using a multinomial logit model with the panel-data set of Vietnam manufacturing firms, this paper investigates the impacts of foreign direct investment (FDI) - small and medium enterprises (SMEs) linkages and other factors on SMEs' participation in the global value chain (GVC). We consider GVC firms are those engaging in any of the three modes including (i) using domestic inputs to export (D2E), (ii) using imported inputs to produce for the domestic market (I2P), (iii) using imported inputs to export (I2E). We discover that FDI-SME linkages statistically encourage Vietnamese SMEs to integrate into the GVC via I2P and I2E, while no statistical association between FDI-SME linkage and D2E participation is found. GVCs participation likelihood is also positively correlated with the introduction of new product introduction. The establishment of firms' production facilities in industrial zones and foreign ownership are both reported to be significantly decisive factors to SMEs' decisions on GVC participation. Besides, there is a strong association between firms' attributes, i.e. employment, capital intensity as well as financial access, and their participation in the GVC. Local governance quality (proxied by the Provincial Competitiveness Index) and the share of skilled labor at the province-level can facilitate firms' integration into GVCs, while greater market concentration may be a hurdle to such potential.
Effects of Glycerol and Shikimic Acid on Rapamycin Production in Streptomyces rapamycinicus
( Huyen Thi Huong La ),( Thao Kim Nu Nguyen ),( Hang Thuy Dinh ),( Quyen Minh Huynh Nguyen ),( Minh Hong Nguyen ) 한국미생물 · 생명공학회 2020 한국미생물·생명공학회지 Vol.48 No.3
Rapamycin, derived from Streptomyces rapamycinicus, is an important bioactive compound having a therapeutic value in managing Parkinson’s disease, rheumatoid arthritis, cancer, and AIDS. Because of its pharmaceutical activity, studies over the past decade have focused on the biosynthesis of rapamycin to enhance its yield. In this study, the effect of rapG on rapamycin production was investigated. The rapG expression vector was constructed by utilizing the integration vector pSET152 under the control of the erythromycin resistance gene (ermE*), a strong constitutive promoter. The rapamycin yield of wild type (WT) and WT/ rapG overexpression mutant strains, under fermentation conditions, was analyzed by high-performance liquid chromatography (HPLC). Our results revealed that overexpression of rapG increased rapamycin production by approximately 4.9-fold (211.4 mg/l) in MD1 containing 15 g/l of glycerol, compared to that of the WT strain. It was also found that Illicium verum powder (10 g/l), containing shikimic acid, enhanced rapamycin production in both WT and WT/rapG strains. Moreover, the amount of rapamycin produced by the WT/rapG strain was statistically higher than that produced by the WT strain. In conclusion, the addition 15 g/l glycerol and 15 g/l I. verum powder produced the optimal conditions for rapamycin production by WT and WT/rapG strains.