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Published By The University Of Danang

1859-1531

Author(s):  
Nguyen Thanh Dat Nguyen

The paper aims to investigate the impact of Corporate Social Responsibility (CSR) practices on the financial performance of oil and gas firms in Asian countries by using a panel data set that includes 23 firms from 7 Asian countries from 2004 to 2017. The empirical results support the research hypothesis that CSR practices have a negative impact on the financial performance of oil and gas companies. This means CSR practices may impose a substantial burden on firms in the oil and gas industry. In addition, we find that different CSR practices have different sizes of impact on firm financial performance. In particular, environment practice has the biggest impact, social practice ranks second, and governance practice has the weakest impact. The main results are also confirmed by several robustness tests.


Author(s):  
Nguyen Thi Quynh Hoa Nguyen

Owning to their unique semantic and structural features, idioms contribute to the richness of language, enabling language users to express their ideas in concise and sophisticated ways. This study is aimed at identifying and analyzing loss and gain in the Vietnamese translational equivalents of the English idioms used in the 4th volume of the Harry Potter novel serial by J.K. Rowling. The translation shift theory of Catford [1], [2] was employed to clarify the fundamental aspects of loss and gain phenomena. The study reveals that loss and gain in lexis or structure occur frequently in translations of idioms, assisting in preserving the idioms’ figurative meanings. It is hoped that the research results can be of some help for teaching, learning and English – Vietnamese translation of idioms.


Author(s):  
Duong Cong Vinh Duong

Coral bleaching events are of concern globally because of their adverse effect on the coral reef ecosystem. However, there is a lack of observed bleaching in many coral reefs in Vietnam, leading to difficulty in implementing the suitable management and protection solutions. The study aims to provide general information about coral bleaching in ST and CLC basing on bleaching alerts of NOAA Coral Reef Watch in 2019. Field data was collected by a photographic method for analyzing and classifying bleached coral. The results showed that coral reefs experienced low bleaching by an average of 8.86% and 9.09% in ST and CLC, respectively. In addition, the study broadly identified the relationship of sea surface temperature and Degree Heating Weeks to coral bleaching in the study area.


Author(s):  
Duong Quang Hung Duong

This study aims to evaluate the diversity of rotifers in psammon in the Central Coast of Vietnam. A total of 64 rotifer species belonging to 17 genera and 14 families were recorded in 10 samples collected at hygropsammon zones of freshwater lakes and ponds in Thua Thien Hue province. Lepadella cristata (Rousselet, 1893), Cephalodella tenuior (Gosse, 1886), and Lindia torulosa Dujardin, 1841 were new record to Vietnam rotifers fauna. Species from the families Lecanidae, Lepadellidae, and Trichocercidae are abundant (containing about 44%, 14%, and 12%, respectively) in the total rotifer species recorded. Psammonxenic species accounted for the largest percentage of the psammic rotifer community with 83%, followed by psammonphiles (11%) and psammonbionts (6%). Our study results enrich the data on the diversity and the ecology of rotifers in Vietnam.


Author(s):  
Phan Hoang Long Phan

This paper examines the relationship among aspects of bank ownership complexity, including ownership dispersion and type, and the quality of bank loan portfolio. The data used for analysis is an unbalanced panel consisting of 13 listed commercial banks in Vietnam for the period of 2010 - 2019. The non-performing loan (NPL) ratio is used as an indicator of loan quality. The results showed that ownership dispersion, calculation based on the Herfindahl–Hirschman Index of large shareholding, improves the loan quality. Foreign ownership is also found to have positive impact on the loan quality. However, there is no relationship established between government ownership and loan quality.


Author(s):  
Ho Hong Quyen Ho

Eco-friendly flocculants of alginic acid, NaHCO3 and CaCl2.2H2O with advantages of strong gelation characteristics were prepared for supporting the removal of phosphate in synthetic wastewater using CaO and Ca(OH)2 as precipitants. The effects of weight ratios of each component in flocculants, dosage of flocculants and initial phosphate concentration were investigated through batch of experiments. The results showed excellent flocculation performance with the weight ratio of alginic acid:NaHCO3 and CaCl2.2H2O at 1:0.3:0.02 and the dosage of flocculants at 0.0050 g/25 mL of phosphate solution in the range of initial phosphate concentration from 50 to 1000 ppm. Comparing to the sample without flocculants, the phosphate removal efficiency using CaO and Ca(OH)2 with the addition of flocculants increased from 19 and 20% to 97% at the initial phosphate concentration of 50 ppm, respectively by filtration of filter paper 2.7 μm.


Author(s):  
Nguyen Minh Tien Nguyen

This study presents the effect of ignition energy (Eig) on ignition delay time (tdelay) and uncertainty of laminar burning velocity (Su0) measurement of lean methane/air mixture in a constant volume combustion chamber. The mixture at an equivalence ratio of 0.6 is ignited using a pair of electrodes at the 2-mm spark gap. Eig is measured by integrating the product of voltage V(t) and current I(t) signals during a discharge period. The in-chamber pressure profiles are analyzed using the pressure-rise method to obtain tdelay and Su0. Su0 approximates 8.0 cm/s. Furthermore, the increasing Eig could shorten tdelay, leading to a faster combustion process. However, when Eig is greater than a critical value, called minimum reliable ignition energy (MRIE), the additional elevating Eig has the marginal effect on tdelay and Su0. The existence of MRIE supports to optimize the ignition systems and partly explains why extreme-high Eig>> MRIE has less contribution to engine performance.


Author(s):  
Tran Thi Thuy Oanh Tran

E-learning is being widely deployed and gradually becoming a popular form of teaching in universities today. To achieve the quality of e-learning teaching requires the impact of many factors, in which the e-learning environment of students is important. This paper explored experiences on e-learning environment of students of The University of Danang - University of Foreign Language Studies (UD-UFLS) to improve e-learning environment of the university's students. The study refered to most students’ awareness of the importance of e-learning at university. The advantages and disadvantages of e-learning at the university (UD-UFLS) have also been identified. Through the results of the student survey, the content of the teacher's skills, the content of policies and management of e-learning activities, facilities and funding for e-learning implementation, class size, and student e-learning culture in e-learning are rated. The results of a questionnaire survey of 407 students of the UD-UFLS show a picture of students' e-learning environment and are the basis for proposing some measures to improve e-learning environment of the university's students.


Author(s):  
Nguyen Thi Hong Chuong Nguyen

Aralia armata is one of the common herb species in mountainous areas, especially in the northern mountainous areas of Vietnam, which has potential in pharmaceutical and agricultural industries. Herein, we report that an oleanolic acid saponin named pseudogisenoside RT1 methyl ester (A) was isolated from the roots of the species Aralia armata. The fractionated extracts of dichloromethane, ethyl acetate, water and compound A were investigated for their molluscicidal effects, specifically on Pomacea canaliculata. The tests showed that the extracts and compound A from A. armata roots had good activity against P. canaliculata snail. In particular, compound A had a Lethal concentration of 50 (LC50) value of 16.443 µg/mL.


Author(s):  
Pham Quy Muoi Pham

In [1], Nesterov has introduced an optimal algorithm with constant step-size,  with  is the Lipschitz constant of objective function. The algorithm is proved to converge with optimal rate . In this paper, we propose a new algorithm, which is allowed nonconstant step-sizes . We prove the convergence and convergence rate of the new algorithm. It is proved to have the convergence rate  as the original one. The advance of our algorithm is that it is allowed nonconstant step-sizes and give us more free choices of step-sizes, which convergence rate is still optimal. This is a generalization of Nesterov's algorithm. We have applied the new algorithm to solve the problem of finding an approximate solution to the integral equation.


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