THU DAU MOT UNIVERSITY
Journal of Science

journal homepage: ejs.tdmu.edu.vn

ISSN 2615-9635

Aims and Scope

Thu Dau Mot University Journal of Science (EJS) is published by Thu Dau Mot University under the authorization of Ministry of Information and Communications to serve the interests of both Vietnam and international lectures and scientists associated with higher education, postgraduate training and scientific research for community. The aim is to publish high quality research papers in a variety of fields of social sciences, such as humanities, education and economics. The Journal, which is a forum for the presentation of innovative ideas, approaches, and research projects, facilitates knowledge exchange among lecturers, researchers, and education professionals. We accept submissions of articles which report new outcome of empirical research, review of the field, and discourse of scholarly debate. This is an online quarterly multi-discipline journal, which is schedules to be published on January 15, April 15, July 15 and October 15 of every year. The following areas of disciplines are to be covered in the Journal: (1) Natural Science, (2) Social Science & Humanities, (3) Technology Engineering, (5) Economics, (6) Management, (7) Education, and (8) Other areas in the development of high Education.

Current Issue
On the lower semicontinuity of the solution map- ping for parametric vector mixed quasivariational inequality problem of the Minty type
by Nguyen Van Hung, Vo Viet Tri
Article Info: Received 10 April. 2020, Accepted 7 May. 2020, Available online 30 May. 2020
Corresponding author: trivv@tdmu.edu.vn
Doi: 10.37550/tdmu.EJS/2020.02.041

| PDF

In this paper, we study a class of parametric vector mixed quasivariational inequality problem of the Minty type (in short, (MQVIP)). Afterward, we establish some sufficient conditions for the stability properties such as the inner-openness, lower semicontinuity and Hausdorff lower semicontinuity of the solution mapping for this problem. The results presented in this paper is new and wide to the corresponding results in the literature

The nice m-system of parameters for Artinian modules
by Nguyen Thi Khanh Hoa
Article Info: Received 02 Jan. 2020, Accepted 29 Feb. 2020, Available online 15 Apr. 2020
Corresponding author: hoanguyenthikhanh@gmail.com
Doi: 10.37550/tdmu.EJS/2020.02.042

| PDF

This paper restates the definition of the nice m-system of parameters for Artinian modules. It also shows its effects on the differences between lengths and multiplicities of certain systems of parameters for Artinian modules:

In particular, if  is a nice m-system of parameters then the function  is a polynomial having very nice form. Moreover, we will prove some properties of the nice m-system of parameters for Artinian modules. Especially, its effect on the annihilation of local homology modules of Artinian module A.

Removal of copper (Cu2+) ions from aqueous solutions by adsorption on activated macadamia carbon using H3PO4 activating agent
by Dao Minh Trung , Dang Thi Hoai Thu, Nguyen Thi Thanh Tram
Article Info: Received 29 Dec. 2019, Accepted 20 Mar. 2020, Available online 15 Apr. 2020
Corresponding author: trungtd@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: 10.37550/tdmu.EJS/2020.02.043

| PDF

The study aims to investigate the possibility of processing copper metal (Cu2+) with activated carbon prepared from macadamia shell. Activated carbon is prepared from Macadamia shell by chemical agent H3PO4 with coke ratio: H3PO4 = 1:1, optimal temperature condition is 5000C and burning time is 60 minutes. Using the assumed Cu2+ metal treats materials in the laboratory with a concentration of 30ppm. The  research to result ability material adsorbed Cu2+ metal achieve good performance 95.92% handle, corresponding to the concentration of Cu2+ reduced from 30 mg/l to 1.2mg/l in optimal conditions is pH = 4.5 , dosage 1.8g/l, time 30 minutes. The results showed that activated carbon prepared from macadamia husk with chemical agent H3PO4 was capable of treating copper metal in wastewater.

Evaluate the efficiency of the Environmental Management System Iso 14001:2015 at The Vietnam Onamba Company
by Nguyen Thi Xuan Hanh, Do Thi Kim Ty
Article Info: Received 15 Dec. 2019, Accepted 20 Mar. 2020, Available online 15 Apr. 2020
Corresponding author: nguyenthixuanhanh@gmail.com
Doi: 10.37550/tdmu.EJS/2020.02.044

| PDF

Nowadays, the benefits of ISO 14001:2015 abound, for minimizing environmental footprints, providing operational improvements, bringing lucrative business and improving the company’s image. There is an annual audit to decide if the company’s environmental management system meets the requirements of ISO 14001:2015. This is a significant audit that strongly affects the current certificate. The study to “Evaluate the efficiency of the environmental management system ISO 14001:2015 at the Vietnam Onamba Company” has been conducted to research the internal audit and examine any discordance in the environmental management system. The study carries out the internal audit of the environmental management system ISO 14001:2015 at VTO company by 3P method (P1: Paper check, P2: People interview, P3: Practice Observe). The result of the study showed a minor discordance at (6.2) Environmental Objectives and planning to achieve them. Regarding other clauses, they meet the requirements of the environmental management system. The result shows that the responsibility and careful observation of the company in controlling the system. The study evaluates reducing consumption (electricity, water, and chemicals) through collecting and comparing the data between 2017 and 2018. The results show the efficiency of reducing consumption: monthly electricity consumption reduced 21,86% (377 MWh); monthly water usage reduced 17,89% (1421 m3); annual chemical usage reduced from 3 to 6%. 

Removal of Cu2+ In sewage with macadamia coal activated by K2CO3
by Dao Minh Trung, Duong Van Tung, Trinh Diep Phuong Danh
Article Info: Received 10 Dec. 2019, Accepted 30 Mar. 2020, Available online 15 Apr. 2020
Corresponding author: trungtd@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: 10.37550/tdmu.EJS/2020.02.045

| PDF

Investigation of the possibility of treating wastewater containing Cu2+ heavy metal with activated carbon material prepared from macadamia husk with activating K2CO3 in Optimal conditions such as temperature 6500C and burning time is 60 minutes. Survey results show that coal with the ability to handle heavy metals is best at 84.02% in optimal conditions such as pH=5 and time. Baking is 30 minutes. The results show similarities with other research results and are applicable to wastewater treatment Cu2+.

Isolating some fungi strains from diease roots of Dipterocarpus dyeri planted at the nursery in Dong Nai province
by Tran Ngoc Hung
Article Info: Received 25 Dec. 2019, Accepted 15 Jan. 2020, Available online 15 Apr. 2020
Corresponding author: hungtngoc@tdmu.edu.vn
Doi: 10.37550/tdmu.EJS/2020.02.046

| PDF

Dipterocarpus dyeri is a typical plant of tropical evergreen moist forest at Southeast Vietnam. These plants have been planted popularly at parks and urban streets for the shade and it has been commonly materials for timber industry. Multiplication of Dipterocarpus dyeri at nurseries could face to some diseases, such as the withered disease cause serial death. Our study isolated three disease fungi strains from the root areas of the diseased Dipterocarpus dyeri planted Ma Da nursery, Dong Nai province. Result of 28s rDNA sequencing showed these fungi belong to Ophiostoma eucalypticagena, Aspergillus nidulans and Collectotrichum gloeosporioides. This result is base for conducting the following studies to control the withered disease on Dipterocarpus dyeri at the nursery.

Using modified macadamia carbon by H2O2 as adsorbent to remove zinc (Zn2+) in wastewater
by Dao Minh Trung, Nguyen Kim Nga, Le Thi Dao, Trinh Diep Phuong Danh
Article Info: Received 20 Feb. 2020, Accepted 15Mar. 2020, Available online 15 Apr. 2020
Corresponding author: trungtd@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: 10.37550/tdmu.EJS/2020.02.047

| PDF

Using modified macadamia carbon by H2O2 as adsorbent to remove Zn2+ with H2O2 25% in 48 hours. The Parameters, such as pH, dosage and adsorption time affect the processing ability of modified macadamia carbon H2O2. The maximum removal efficiency of 64.52% was obtained at a pH of 4.5, the processing time is 80 minutes, dosage 1.8 g/L and an initial heavy metal concentration of 25ppm.

Assessing the competitive advantages of tourism potentials in Tuy Hoa city, Phu Yen province
by Nguyen Hien Than, Nguyen Huynh Anh Tuyet, Che Dinh Ly
Article Info: Received 18 Dec. 2019, Accepted 20 Mar. 2020, Available online 15 Apr. 2020
Corresponding author: thannh@tdmu.edu.vn (Nguyen Hien Than MA)
Doi: 10.37550/tdmu.EJS/2020.02.048

| PDF

This paper presents a Quantified SWOT (Strengths, Weaknesses, Opportunities and Threats) analytical method and an analytical hierarchy process method which provides more detailed and quantified information on tourism potential in Tuy Hoa city. Quantified SWOT analysis was used to assess the competing strength of Tuy Hoa’s tourism potential with other places. The results of the study presented that Tuy Hoa city has many advantages of beautiful natural landscapes, nature, rivers and mountains. The results of the comparing value of internal and external factors of Tuy Hoa’s tourism potential indicated it under high competitive pressure from neighbor destinations such as Phan Thiet, Hue, Nha Trang and Da Nang. Tuy Hoa’s tourism potential was lower than that of neighbor cities but it has more attractive tourism features.

Removal of copper (Cu2+) by preparation modified carbon from macadamia shells by chemical agent with H2O2 in wastewater
by Dao Minh Trung, Le Nguyen Phuong Anh, Nguyen Thanh Quang, Nguyen Thị Thanh Tram
Article Info: Received 26 Dec. 2019, Accepted 30 Mar. 2020, Available online 15 Apr.2020
Corresponding author: trungtd@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: 10.37550/tdmu.EJS/2020.02.049

| PDF

Macadamia shells were used to prepare modified carbon by chemical agent H2O2 (25%) in 48 hours with coke ratio: H2O2 = 1:10. Modified carbon from Macadamia shells with chemical agent H2O2 has capable of adsorption heavy metal copper (Cu 2+) at an assumption concentration is 30ppm in the optimum conditions such as pH = 4, dose is 1.8 g/l, and the processing time is 30 minutes. The result showed that the adsorption ability of the material reached the highest efficiency is 78.33%. This result showed that modified carbon from shells Macadamia by chemical agent H2O2 capable of removing applications on heavy metal copper (Cu2+) in wastewater.

Semantic features of English collocations with the verb ‘make’ in international criminal documents: difficulties with, and sugges-tions for learning and translating
by Le Huong Hoa, Luong Duy Thanh
Article Info: Received 11 Jan. 2019, Accepted 24 Mar. 2020, Available online 15 Apr. 2020
Corresponding author: hoalehuong@yahoo.com
Doi: https://doi.org/10.37550/tdmu.EJS/2020.02.050

| PDF

One of the most problematic areas for foreign language learning is collocation. It is often seen as a seemingly insurmountable obstacle to the attainment of native like fluency. The following study takes an approach as a linguistic one by analyzing semantic features of the English collocations with ‘make’, which is widely used in the international criminal documents. The thesis analyzing their semantic features according to the categorization of the English collocations with ‘make’ used in the international criminal documents in order to find out the difficulties for learners and translators in dealing with these collocations as well as to impose the suggestions for these difficulties.

English language Errors in Academic writing: An analysis of English research papers of Thu Dau Mot University Journal of Science
by Nguyen Thi Man
Article Info: Received 16 Jan. 2020, Accepted 25 Mar. 2020, Available online 15 Apr. 2020
Corresponding author: ntman@tdmu.edu.vn
Doi: https://doi.org/10.37550/tdmu.EJS/2020.02.051

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This research aims to describe English language errors in the scientific papers. The research data consists of 104 scientific articles that authors sent to Journal of Thu Dau Mot University. The quantitative method was applied in the form of frequency charts for each category of surface strategy taxonomy and comparative analysis. Based on the analysis theory of grammatical errors, all of the errors in these articles were identified and classified into different categorizations. The findings of the study showed that the authors’ writings were committed three main error groups: Lexical errors are the highest with 281 (49%); the number of Syntactic errors are ranked the second with 222 (39%); Morphological errors are the lowest with 69 (12%). On the basis of these results it is figured out that the authors still have difficulties in writing a research papers in English because they are not English major. Moreover the grammar of English is known as their foreign language. Another reason that the writer made errors is uninterested in organization of their papers. From the study findings above, the researcher suggests some implications to help authors improve their academic writing and meet English international standard.

Students’ difficulties in learning English for specific purpose grammar at the People’s Police University
by Le Huong Hoa, Le Quang Truc (People’s Police University)
Article Info: Received 11 Nov. 2019, Accepted 24 Dec. 2019, Available online 15 Feb. 2020
Corresponding author: hoalehuong@yahoo.com (Le Huong Hoa PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.001

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This study investigated grammatical difficulties encountered by students of the People’s Police University while learning grammar in ESP courses. The design included questionnaires to teachers and students, and classroom participant observations. The findings indicated that the student respondents only perceived four target features to be difficult to learn. The results also showed that the students’ perceptions of grammatical difficulty were influenced by several factors including the inherent complexity of rules, L1 transfer, students’ differences in language aptitude, students’ infrequency of practice, and teaching methodology. The findings will hopefully be useful for teachers and researchers with an interest in this line of research.

Key words: grammatical features, perceived, ESP grammar.

A study of fixed points and hopf bifurcation of hindmarsh-rose model
by Phan Van Long Em (An Giang university, Vietnam)
Article Info: Received 10 Sep. 2019, Accepted 20 Oct. 2019, Available online 15 Feb. 2020
Corresponding author: pvlem@agu.edu.vn (Phan Van Long Em PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.002

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In this article, a class of Hindmarsh-Rose model is studied. First, all necessary conditions for the parameters of system are found in order to have one stable fixed point which presents the resting state for this famous model. After that, using the Hopf’s theorem proofs analytically the existence of a Hopf bifurcation, which is a critical point where a system’s stability switches and a periodic solution arises. More precisely, it is a local bifurcation in which a fixed point of a dynamical system loses stability, as a pair of complex conjugate eigenvalues cross the complex plane imaginary axis. Moreover, with the suitable assumptions for the dynamical system, a small-amplitude limit cycle branches from the fixed point.

 

Keywords: Hindmarsh-Rose model, fixed point, Hopf bifurcation, limit cycle

Assessment of the effects of organic solvent to the health of workers in Printer - case study of Fuji Seal Vietnam Company, in VSIP II industrial park, Binh Duong province
by Truong Quoc Minh, Nguyen Hien Than (Thu Dau Mot University, Vietnam)
Article Info: Received 03 Sep. 2019, Accepted 20 Nov. 2019, Available online 15 Feb. 2020
Corresponding author: minhtq@tdmu.edu.vn (Truong Quoc Minh M.A.)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.003

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ABSTRACT

The study was conducted at Fuji Seal Vietnam Co., Ltd. to examine the exposure and health risks of workers working in the printing and ink phase area when exposed to solvent vapor through the respiratory apparatus Toluene, Methyl Ethyl Ketone, Ethyl Acetate, Isopropyl Acohol. The results show that: During the monitoring period from July to November 2016, the amount of solvent vapor in the printing area and ink phase is quite high, at the highest Toluene printing area, it was 2.63 times higher than the standard equal to the health risk HQ male is 2.61 and HQ female is 3.37; Ethyl Acetate exceeded the highest of 4.34 times equal to the male HQ risk ratio of 4.29 and female HQ equal to 5.53; MEK exceeds 8.43 times equal to the health risk HQ male is 8.36 and HQ female is 10.79;  Isopropyl Acohol exceeds 8.4 times equal to the health risk HQ male is 8.33 and HQ female is 10.75; At the inking area, MEK exceeds 8.43 times equal to the health risk HQ male is 8.36 and HQ female is 10.79. From the calculated data - analysis, found that the health of workers working in the printing and inking areas had high risks, the ability of workers suffering from diseases such as headache, dizziness, skin damage,... and especially respiratory failure.

Key words: Fuji Seal Company, health risks, solvent vapor

Methylene orange handling of cock cake casted by H3PO4 chemicals
by Dao Minh Trung, Nguyen Thi Tuyet Ngan, Nguyen Thanh Quang, Le Thi Dao, Trinh Diep Phuong Danh (Thu Dau Mot University, Vietnam)
Article Info: Received 05 Nov. 2019, Accepted 20 Dec. 2019, Available online 15 Feb. 2020
Corresponding author: trungdm@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.004

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ABSTRACT

Survey of methylene orange wastewater treatment by activated carbon material prepared from macadamia husk with chemical activator H3PO4 shows that coal with the best methylene orange color treatment is achieved Optimal conditions such as pH = 5, coal dose 0.9 g/L and time 120 minutes. The results show that it is applicable to color wastewater treatment and the results are similar to other research results.

 

Key words: Activated carbon H3PO4, Macadamia, adsorption, Methylene Orange.

Investigation of Zn2+ heavy metal handling ability by macadamite activated by H3PO4
by Dao Minh Trung, Tran Phuoc Dong, Trinh Diep Phương Danh (Thu Dau Mot University, Vietnam)
Article Info: Received 30 Oct. 2019, Accepted 15 Dec. 2019, Available online 15 Feb. 2020
Corresponding author: trungtd@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.005

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ABSTRACT

Investigate the possibility of treating wastewater containing heavy metals Zn2+ with activated carbon material prepared from macadamia shell with chemical activating agent H3PO4, showing high efficiency of adsorption of Zn2+. The results of the study showed that activated carbon with H3PO4 activating agent has high adsorption capacity, capable of handling Zn2+ best at pH = 4.5, dosage 1.8 g/L and time is 120 minutes. . The results show similarities with other research results and are capable of treating wastewater containing heavy metals Zn2+.

 

Key word: Macadamia, metal processing, H3PO4, activated carbon

Survey of zinc metal processing capability with coal-chemistry activated carbon by chemical K2CO3
by Dao Minh Trung, Tran Thi Bich Tram, Le Thi Dao, Trinh Diep Phuong Danh (Thu Dau Mot University, Vietnam)
Article Info: Received 11 Nov. 2019, Accepted 24 Dec. 2019, Available online 15 Feb. 2020
Corresponding author: trungtd@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.006

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ABSTRACT

Seed coat macadamia preparation of activated carbon with chemical agent K2CO3 from macadamia shells as per ratio: K2CO3: distilled water = 1:1:10ml, optimal temperature condition 6500C and burning time 60 minutes. Efficiency removal of zinc (II) in wastewater efficiency (53.42%) with the concentration of 25ppm, conducted a survey at pH = 4.5 with 1.8g/l of carbon, treated in 100 minutes. Survey results have similarities with other studies and are applicable to application removal of zinc (II) in wastewater.

 

Key words: Activated carbon, adsorbed Zn2+, K2CO3, Macadamia

Application of simulation in 3D space to teaching and science research
by Ngo Bao (Thu Dau Mot University, Vietnam)
Article Info: Received 30 Nov. 2019, Accepted 15 Jan. 2020, Available online 15 Feb. 2020
Corresponding author: baon@tdmu.edu.vn (Ngo Bao M.A.)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.007

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ABSTRACT

This article introduces the general issues and benefits of simulation in teaching and scientific research. Thereby, the author illustrates by making 3D drawings, assemblies, videos simulating machine structures for teaching Theoretical mechanics, Construction machine subjects and the author's studies in the mechanical field.

The application of simulation in teaching is to create videos by using Solidworks software, simulating the operating principle of machine structures. After that, show the videos to the students, excite them and make the lesson lively. And the simulation application in scientific research is mentioned as the way to use 3D drawings and simulation videos to preview the research results, promptly fix the wrong places. Since then, the research is quick, cost reduction is not worth it.

The results of this paper are to point out the unique benefits that contribute positively to simulation in teaching and in scientific research.

 

Key words: cranes, figures, hoists, schemas, simulations

On the lower semicontinuity of the solution map- ping for parametric vector mixed quasivariational inequality problem of the Minty type
by Nguyen Van Hung, Vo Viet Tri
Article Info: Received 10 April. 2020, Accepted 7 May. 2020, Available online 30 May. 2020
Corresponding author: trivv@tdmu.edu.vn
Doi: 10.37550/tdmu.EJS/2020.02.041

| PDF

In this paper, we study a class of parametric vector mixed quasivariational inequality problem of the Minty type (in short, (MQVIP)). Afterward, we establish some sufficient conditions for the stability properties such as the inner-openness, lower semicontinuity and Hausdorff lower semicontinuity of the solution mapping for this problem. The results presented in this paper is new and wide to the corresponding results in the literature

The nice m-system of parameters for Artinian modules
by Nguyen Thi Khanh Hoa
Article Info: Received 02 Jan. 2020, Accepted 29 Feb. 2020, Available online 15 Apr. 2020
Corresponding author: hoanguyenthikhanh@gmail.com
Doi: 10.37550/tdmu.EJS/2020.02.042

| PDF

This paper restates the definition of the nice m-system of parameters for Artinian modules. It also shows its effects on the differences between lengths and multiplicities of certain systems of parameters for Artinian modules:

In particular, if  is a nice m-system of parameters then the function  is a polynomial having very nice form. Moreover, we will prove some properties of the nice m-system of parameters for Artinian modules. Especially, its effect on the annihilation of local homology modules of Artinian module A.

Removal of copper (Cu2+) ions from aqueous solutions by adsorption on activated macadamia carbon using H3PO4 activating agent
by Dao Minh Trung , Dang Thi Hoai Thu, Nguyen Thi Thanh Tram
Article Info: Received 29 Dec. 2019, Accepted 20 Mar. 2020, Available online 15 Apr. 2020
Corresponding author: trungtd@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: 10.37550/tdmu.EJS/2020.02.043

| PDF

The study aims to investigate the possibility of processing copper metal (Cu2+) with activated carbon prepared from macadamia shell. Activated carbon is prepared from Macadamia shell by chemical agent H3PO4 with coke ratio: H3PO4 = 1:1, optimal temperature condition is 5000C and burning time is 60 minutes. Using the assumed Cu2+ metal treats materials in the laboratory with a concentration of 30ppm. The  research to result ability material adsorbed Cu2+ metal achieve good performance 95.92% handle, corresponding to the concentration of Cu2+ reduced from 30 mg/l to 1.2mg/l in optimal conditions is pH = 4.5 , dosage 1.8g/l, time 30 minutes. The results showed that activated carbon prepared from macadamia husk with chemical agent H3PO4 was capable of treating copper metal in wastewater.

Evaluate the efficiency of the Environmental Management System Iso 14001:2015 at The Vietnam Onamba Company
by Nguyen Thi Xuan Hanh, Do Thi Kim Ty
Article Info: Received 15 Dec. 2019, Accepted 20 Mar. 2020, Available online 15 Apr. 2020
Corresponding author: nguyenthixuanhanh@gmail.com
Doi: 10.37550/tdmu.EJS/2020.02.044

| PDF

Nowadays, the benefits of ISO 14001:2015 abound, for minimizing environmental footprints, providing operational improvements, bringing lucrative business and improving the company’s image. There is an annual audit to decide if the company’s environmental management system meets the requirements of ISO 14001:2015. This is a significant audit that strongly affects the current certificate. The study to “Evaluate the efficiency of the environmental management system ISO 14001:2015 at the Vietnam Onamba Company” has been conducted to research the internal audit and examine any discordance in the environmental management system. The study carries out the internal audit of the environmental management system ISO 14001:2015 at VTO company by 3P method (P1: Paper check, P2: People interview, P3: Practice Observe). The result of the study showed a minor discordance at (6.2) Environmental Objectives and planning to achieve them. Regarding other clauses, they meet the requirements of the environmental management system. The result shows that the responsibility and careful observation of the company in controlling the system. The study evaluates reducing consumption (electricity, water, and chemicals) through collecting and comparing the data between 2017 and 2018. The results show the efficiency of reducing consumption: monthly electricity consumption reduced 21,86% (377 MWh); monthly water usage reduced 17,89% (1421 m3); annual chemical usage reduced from 3 to 6%. 

Removal of Cu2+ In sewage with macadamia coal activated by K2CO3
by Dao Minh Trung, Duong Van Tung, Trinh Diep Phuong Danh
Article Info: Received 10 Dec. 2019, Accepted 30 Mar. 2020, Available online 15 Apr. 2020
Corresponding author: trungtd@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: 10.37550/tdmu.EJS/2020.02.045

| PDF

Investigation of the possibility of treating wastewater containing Cu2+ heavy metal with activated carbon material prepared from macadamia husk with activating K2CO3 in Optimal conditions such as temperature 6500C and burning time is 60 minutes. Survey results show that coal with the ability to handle heavy metals is best at 84.02% in optimal conditions such as pH=5 and time. Baking is 30 minutes. The results show similarities with other research results and are applicable to wastewater treatment Cu2+.

Isolating some fungi strains from diease roots of Dipterocarpus dyeri planted at the nursery in Dong Nai province
by Tran Ngoc Hung
Article Info: Received 25 Dec. 2019, Accepted 15 Jan. 2020, Available online 15 Apr. 2020
Corresponding author: hungtngoc@tdmu.edu.vn
Doi: 10.37550/tdmu.EJS/2020.02.046

| PDF

Dipterocarpus dyeri is a typical plant of tropical evergreen moist forest at Southeast Vietnam. These plants have been planted popularly at parks and urban streets for the shade and it has been commonly materials for timber industry. Multiplication of Dipterocarpus dyeri at nurseries could face to some diseases, such as the withered disease cause serial death. Our study isolated three disease fungi strains from the root areas of the diseased Dipterocarpus dyeri planted Ma Da nursery, Dong Nai province. Result of 28s rDNA sequencing showed these fungi belong to Ophiostoma eucalypticagena, Aspergillus nidulans and Collectotrichum gloeosporioides. This result is base for conducting the following studies to control the withered disease on Dipterocarpus dyeri at the nursery.

Using modified macadamia carbon by H2O2 as adsorbent to remove zinc (Zn2+) in wastewater
by Dao Minh Trung, Nguyen Kim Nga, Le Thi Dao, Trinh Diep Phuong Danh
Article Info: Received 20 Feb. 2020, Accepted 15Mar. 2020, Available online 15 Apr. 2020
Corresponding author: trungtd@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: 10.37550/tdmu.EJS/2020.02.047

| PDF

Using modified macadamia carbon by H2O2 as adsorbent to remove Zn2+ with H2O2 25% in 48 hours. The Parameters, such as pH, dosage and adsorption time affect the processing ability of modified macadamia carbon H2O2. The maximum removal efficiency of 64.52% was obtained at a pH of 4.5, the processing time is 80 minutes, dosage 1.8 g/L and an initial heavy metal concentration of 25ppm.

Assessing the competitive advantages of tourism potentials in Tuy Hoa city, Phu Yen province
by Nguyen Hien Than, Nguyen Huynh Anh Tuyet, Che Dinh Ly
Article Info: Received 18 Dec. 2019, Accepted 20 Mar. 2020, Available online 15 Apr. 2020
Corresponding author: thannh@tdmu.edu.vn (Nguyen Hien Than MA)
Doi: 10.37550/tdmu.EJS/2020.02.048

| PDF

This paper presents a Quantified SWOT (Strengths, Weaknesses, Opportunities and Threats) analytical method and an analytical hierarchy process method which provides more detailed and quantified information on tourism potential in Tuy Hoa city. Quantified SWOT analysis was used to assess the competing strength of Tuy Hoa’s tourism potential with other places. The results of the study presented that Tuy Hoa city has many advantages of beautiful natural landscapes, nature, rivers and mountains. The results of the comparing value of internal and external factors of Tuy Hoa’s tourism potential indicated it under high competitive pressure from neighbor destinations such as Phan Thiet, Hue, Nha Trang and Da Nang. Tuy Hoa’s tourism potential was lower than that of neighbor cities but it has more attractive tourism features.

Removal of copper (Cu2+) by preparation modified carbon from macadamia shells by chemical agent with H2O2 in wastewater
by Dao Minh Trung, Le Nguyen Phuong Anh, Nguyen Thanh Quang, Nguyen Thị Thanh Tram
Article Info: Received 26 Dec. 2019, Accepted 30 Mar. 2020, Available online 15 Apr.2020
Corresponding author: trungtd@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: 10.37550/tdmu.EJS/2020.02.049

| PDF

Macadamia shells were used to prepare modified carbon by chemical agent H2O2 (25%) in 48 hours with coke ratio: H2O2 = 1:10. Modified carbon from Macadamia shells with chemical agent H2O2 has capable of adsorption heavy metal copper (Cu 2+) at an assumption concentration is 30ppm in the optimum conditions such as pH = 4, dose is 1.8 g/l, and the processing time is 30 minutes. The result showed that the adsorption ability of the material reached the highest efficiency is 78.33%. This result showed that modified carbon from shells Macadamia by chemical agent H2O2 capable of removing applications on heavy metal copper (Cu2+) in wastewater.

Semantic features of English collocations with the verb ‘make’ in international criminal documents: difficulties with, and sugges-tions for learning and translating
by Le Huong Hoa, Luong Duy Thanh
Article Info: Received 11 Jan. 2019, Accepted 24 Mar. 2020, Available online 15 Apr. 2020
Corresponding author: hoalehuong@yahoo.com
Doi: https://doi.org/10.37550/tdmu.EJS/2020.02.050

| PDF

One of the most problematic areas for foreign language learning is collocation. It is often seen as a seemingly insurmountable obstacle to the attainment of native like fluency. The following study takes an approach as a linguistic one by analyzing semantic features of the English collocations with ‘make’, which is widely used in the international criminal documents. The thesis analyzing their semantic features according to the categorization of the English collocations with ‘make’ used in the international criminal documents in order to find out the difficulties for learners and translators in dealing with these collocations as well as to impose the suggestions for these difficulties.

English language Errors in Academic writing: An analysis of English research papers of Thu Dau Mot University Journal of Science
by Nguyen Thi Man
Article Info: Received 16 Jan. 2020, Accepted 25 Mar. 2020, Available online 15 Apr. 2020
Corresponding author: ntman@tdmu.edu.vn
Doi: https://doi.org/10.37550/tdmu.EJS/2020.02.051

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This research aims to describe English language errors in the scientific papers. The research data consists of 104 scientific articles that authors sent to Journal of Thu Dau Mot University. The quantitative method was applied in the form of frequency charts for each category of surface strategy taxonomy and comparative analysis. Based on the analysis theory of grammatical errors, all of the errors in these articles were identified and classified into different categorizations. The findings of the study showed that the authors’ writings were committed three main error groups: Lexical errors are the highest with 281 (49%); the number of Syntactic errors are ranked the second with 222 (39%); Morphological errors are the lowest with 69 (12%). On the basis of these results it is figured out that the authors still have difficulties in writing a research papers in English because they are not English major. Moreover the grammar of English is known as their foreign language. Another reason that the writer made errors is uninterested in organization of their papers. From the study findings above, the researcher suggests some implications to help authors improve their academic writing and meet English international standard.

Students’ difficulties in learning English for specific purpose grammar at the People’s Police University
by Le Huong Hoa, Le Quang Truc (People’s Police University)
Article Info: Received 11 Nov. 2019, Accepted 24 Dec. 2019, Available online 15 Feb. 2020
Corresponding author: hoalehuong@yahoo.com (Le Huong Hoa PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.001

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This study investigated grammatical difficulties encountered by students of the People’s Police University while learning grammar in ESP courses. The design included questionnaires to teachers and students, and classroom participant observations. The findings indicated that the student respondents only perceived four target features to be difficult to learn. The results also showed that the students’ perceptions of grammatical difficulty were influenced by several factors including the inherent complexity of rules, L1 transfer, students’ differences in language aptitude, students’ infrequency of practice, and teaching methodology. The findings will hopefully be useful for teachers and researchers with an interest in this line of research.

Key words: grammatical features, perceived, ESP grammar.

A study of fixed points and hopf bifurcation of hindmarsh-rose model
by Phan Van Long Em (An Giang university, Vietnam)
Article Info: Received 10 Sep. 2019, Accepted 20 Oct. 2019, Available online 15 Feb. 2020
Corresponding author: pvlem@agu.edu.vn (Phan Van Long Em PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.002

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In this article, a class of Hindmarsh-Rose model is studied. First, all necessary conditions for the parameters of system are found in order to have one stable fixed point which presents the resting state for this famous model. After that, using the Hopf’s theorem proofs analytically the existence of a Hopf bifurcation, which is a critical point where a system’s stability switches and a periodic solution arises. More precisely, it is a local bifurcation in which a fixed point of a dynamical system loses stability, as a pair of complex conjugate eigenvalues cross the complex plane imaginary axis. Moreover, with the suitable assumptions for the dynamical system, a small-amplitude limit cycle branches from the fixed point.

 

Keywords: Hindmarsh-Rose model, fixed point, Hopf bifurcation, limit cycle

Assessment of the effects of organic solvent to the health of workers in Printer - case study of Fuji Seal Vietnam Company, in VSIP II industrial park, Binh Duong province
by Truong Quoc Minh, Nguyen Hien Than (Thu Dau Mot University, Vietnam)
Article Info: Received 03 Sep. 2019, Accepted 20 Nov. 2019, Available online 15 Feb. 2020
Corresponding author: minhtq@tdmu.edu.vn (Truong Quoc Minh M.A.)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.003

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ABSTRACT

The study was conducted at Fuji Seal Vietnam Co., Ltd. to examine the exposure and health risks of workers working in the printing and ink phase area when exposed to solvent vapor through the respiratory apparatus Toluene, Methyl Ethyl Ketone, Ethyl Acetate, Isopropyl Acohol. The results show that: During the monitoring period from July to November 2016, the amount of solvent vapor in the printing area and ink phase is quite high, at the highest Toluene printing area, it was 2.63 times higher than the standard equal to the health risk HQ male is 2.61 and HQ female is 3.37; Ethyl Acetate exceeded the highest of 4.34 times equal to the male HQ risk ratio of 4.29 and female HQ equal to 5.53; MEK exceeds 8.43 times equal to the health risk HQ male is 8.36 and HQ female is 10.79;  Isopropyl Acohol exceeds 8.4 times equal to the health risk HQ male is 8.33 and HQ female is 10.75; At the inking area, MEK exceeds 8.43 times equal to the health risk HQ male is 8.36 and HQ female is 10.79. From the calculated data - analysis, found that the health of workers working in the printing and inking areas had high risks, the ability of workers suffering from diseases such as headache, dizziness, skin damage,... and especially respiratory failure.

Key words: Fuji Seal Company, health risks, solvent vapor

Methylene orange handling of cock cake casted by H3PO4 chemicals
by Dao Minh Trung, Nguyen Thi Tuyet Ngan, Nguyen Thanh Quang, Le Thi Dao, Trinh Diep Phuong Danh (Thu Dau Mot University, Vietnam)
Article Info: Received 05 Nov. 2019, Accepted 20 Dec. 2019, Available online 15 Feb. 2020
Corresponding author: trungdm@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.004

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ABSTRACT

Survey of methylene orange wastewater treatment by activated carbon material prepared from macadamia husk with chemical activator H3PO4 shows that coal with the best methylene orange color treatment is achieved Optimal conditions such as pH = 5, coal dose 0.9 g/L and time 120 minutes. The results show that it is applicable to color wastewater treatment and the results are similar to other research results.

 

Key words: Activated carbon H3PO4, Macadamia, adsorption, Methylene Orange.

Investigation of Zn2+ heavy metal handling ability by macadamite activated by H3PO4
by Dao Minh Trung, Tran Phuoc Dong, Trinh Diep Phương Danh (Thu Dau Mot University, Vietnam)
Article Info: Received 30 Oct. 2019, Accepted 15 Dec. 2019, Available online 15 Feb. 2020
Corresponding author: trungtd@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.005

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ABSTRACT

Investigate the possibility of treating wastewater containing heavy metals Zn2+ with activated carbon material prepared from macadamia shell with chemical activating agent H3PO4, showing high efficiency of adsorption of Zn2+. The results of the study showed that activated carbon with H3PO4 activating agent has high adsorption capacity, capable of handling Zn2+ best at pH = 4.5, dosage 1.8 g/L and time is 120 minutes. . The results show similarities with other research results and are capable of treating wastewater containing heavy metals Zn2+.

 

Key word: Macadamia, metal processing, H3PO4, activated carbon

Survey of zinc metal processing capability with coal-chemistry activated carbon by chemical K2CO3
by Dao Minh Trung, Tran Thi Bich Tram, Le Thi Dao, Trinh Diep Phuong Danh (Thu Dau Mot University, Vietnam)
Article Info: Received 11 Nov. 2019, Accepted 24 Dec. 2019, Available online 15 Feb. 2020
Corresponding author: trungtd@tdmu.edu.vn (Dao Minh Trung PhD)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.006

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ABSTRACT

Seed coat macadamia preparation of activated carbon with chemical agent K2CO3 from macadamia shells as per ratio: K2CO3: distilled water = 1:1:10ml, optimal temperature condition 6500C and burning time 60 minutes. Efficiency removal of zinc (II) in wastewater efficiency (53.42%) with the concentration of 25ppm, conducted a survey at pH = 4.5 with 1.8g/l of carbon, treated in 100 minutes. Survey results have similarities with other studies and are applicable to application removal of zinc (II) in wastewater.

 

Key words: Activated carbon, adsorbed Zn2+, K2CO3, Macadamia

Application of simulation in 3D space to teaching and science research
by Ngo Bao (Thu Dau Mot University, Vietnam)
Article Info: Received 30 Nov. 2019, Accepted 15 Jan. 2020, Available online 15 Feb. 2020
Corresponding author: baon@tdmu.edu.vn (Ngo Bao M.A.)
Doi: https://doi.org/10.37550/tdmu.EJS/2020.01.007

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ABSTRACT

This article introduces the general issues and benefits of simulation in teaching and scientific research. Thereby, the author illustrates by making 3D drawings, assemblies, videos simulating machine structures for teaching Theoretical mechanics, Construction machine subjects and the author's studies in the mechanical field.

The application of simulation in teaching is to create videos by using Solidworks software, simulating the operating principle of machine structures. After that, show the videos to the students, excite them and make the lesson lively. And the simulation application in scientific research is mentioned as the way to use 3D drawings and simulation videos to preview the research results, promptly fix the wrong places. Since then, the research is quick, cost reduction is not worth it.

The results of this paper are to point out the unique benefits that contribute positively to simulation in teaching and in scientific research.

 

Key words: cranes, figures, hoists, schemas, simulations

Southeast region of Vietnam - Space identification through administrative boundary
by Phạm Văn Thịnh (Thu Dau Mot University)
Article Info: Received 18 Aug. 2019, Accepted 26 Sep. 2019, Available online 15 Oct. 2019
Corresponding author: thinhpv@tdmu.edu.vn (MA. Phạm Văn Thịnh)
Doi:

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The Southeast region, in prehistory and protohistory, established the space of Dong Nai archeological culture. Since the 16th to 17th centuries, the Southeast had been discovered by the Vietnamese people, in which they established sovereignty and administrative structure. Over three centuries of formation and development, the Southeast region has created many changes in geographic names and administrative structures as required by the historical context of each period. This article presents the overview of the administrative restructuring process in the Southeast region in some important historical milestones during the development process hereof. With the presentation of administrative structures in the Southeast region, the article contributes to systemizing the historical periods of formation and development of the region. It also opens further dialogues for the study of historical and cultural characteristics of the Southeast region.

Keywords: administrative structure, Gia Dinh Department, prehistory and protohistory, Southeast region

The Southeast of Vietnam as a cultural zone and roles of culture - people in the sustainable development of the region
by Trần Ngọc Thêm (University of Social Sciences and Humanities, VNU-HCM)
Article Info: Received 15 Aug. 2019, Accepted 24 Sep. 2019, Available online 15 Oct. 2019
Corresponding author: ngocthem@gmail.com (Prof. Dr.Sc. Trần Ngọc Thêm)
Doi:

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The Southeast plays a very important role in Vietnam’s economic development. Although social science researchers are well located in the Southeast, there remains a paradox that the Southeast culture has not been sufficiently researched into. Applying the method of culture zoning based on three-dimensional change of Subject - Space - Time developed by the author, the article concludes that the Southeast is a separate cultural zone besides the Southwest and lists some typical characteristics of Southeast in terms of the cultural elements (focusing on the organizational culture) and the system of cultural personality characteristics of Vietnamese people in the Southeast. The analysis of Human Development Index (HDI) of Southeast shows that this development is unbalanced and unsustainable. To achieve the balance and sustainability, the Southeast needs to focus on investing in the cultural and human development; reduce the village community and replace it with the social community; minimize the rural nature, agriculture, farmers and enhance the urban civilization, industrial culture and citizens.

Keywords: cultural zone, roles of culture, sustainable development, Southeast

 
Occupation-based social structure in Binh Duong Province, 1999-2009
by Bùi Thế Cường (Thu Dau Mot Universtiy), Vũ Mạnh Lợi (Vietnam Academy of Social Sciences)
Article Info: Received 10 Aug. 2019, Accepted 30 Sep. 2019, Available online 15 Oct. 2019
Corresponding author: cuongbuithe@yahoo.com (Prof. Cuong Bui The)
Doi:

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Binh Duong has rapidly transformed during the period 1999-2009, from a agricultural province to industrial one. The paper explores the shift of occupationbased social structure of Binh Duong during that period. Using the data sets of Census 1999 and 2009, the paper analyses the evolution of the occupational figure in Binh Duong by ten occupational categories and four occupational strata, and the differences in this figure by residence, gender, ethnic, and religious variables. Findings show that the occupational structure of Binh Duong is more developed than the one of the Southern Key Economic Zone. Its change in rural areas is more significant than in urban areas. There are not considerable differences by gender, ethnicity, and religiousness. The findings are suggestive for a further analysis using the data set of Census 2019 on the evolution of occupational figures in Binh Duong during the previous twenty years (1999-2019).

Keywords: Binh Duong, occupational structure, occupation-based social structure, occupational strata, social structure

 
Cultural practices of the Khmer in Binh Duong - Historical particularism approach
by Trần Hạnh Minh Phương (Thu Dau Mot University)
Article Info: Received 15 Aug. 2019, Accepted 24 Sep. 2019, Available online 15 Oct. 2019
Corresponding author: phuongthm@tdmu.edu.vn (Dr. Trần Hạnh Minh Phương)
Doi:

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In 2014, Binh Duong has 2.885 the Khmer people, being the second largest ethnic minority compared to the Hoa people. They have contributed to the multi-ethnic culture of Binh Duong. Hundreds of works on the Khmer in the Mekong Delta considered their culture as a typical of Theravada Buddhist culture in Vietnam but this proposition is not suitable for the Khmer community in An Binh, Phu giao district who is this object of this study. By qualitative data sources from in-depth interviews, participant observations and approach to the historical particularism, this study documented the cultural characteristics of the Khmer in An Binh and analyzed the factors that make culture of the Khmer in An Binh different from the culture of the Khmer in the Mekong Delta. Natural conditions and socio-historical context make the cultural practices of the Khmer in An Binh more similar to the culture of the ethnic groups in the Central Highlands than the Khmer culture in the Mekong delta, especially, customs and folk beliefs.

Keywords: the Khmer culture, the Khmer in Binh Duong, cultural practices

Interpretations about Hoa Anh state
by Nguyễn Văn Giác (Thu Dau Mot University)
Article Info: Received 15 Aug. 2019, Accepted 24 Sep. 2019, Available online 15 Oct. 2019
Corresponding author: vanjack.nguyen@gmail.com (PhD. Nguyễn Văn Giác)
Doi:

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On the basis of coordinating the sources of history materials from Vietnam and China, together with the latest archaeological achievements of Ho citadel, the article has delineated territory, confirmed the chronology frame with the Kings of this kingdom in relation to post-Champa Empire. It is from the aftermath of Vijaya, the two parts of Aryaru (Phu Yen) and Kauthara (Khanh Hoa) belong to Hoa Anh Kingdom, in which, Le Thanh Tong is crowned as Ban La Tra Duyet; the rebellion of this King is the cause for the second conquest, formally taking Ling Chan/ Da Bia as the landmark; Trai A Ma Phat Am is designated as Hoa Anh’s King on the remaining land of Kauthara, but immediately incorporated into Panduranga, forming the state of postChampa.

Keywords: Hoa Anh kingdom, Da Bia mountain, Maha Ban La Tra Duyet, post-Champa