The grindability of segmented grinding wheels produced by Vietnam in rough machining aluminum material

Recently developed in Vietnam segmented grinding wheels is base on the fundamental of discontinuous machining is used to enhance the grindability of abrasive grains. The phenomenon of grinding chips adhesive to space between grains, that make the wheels became "dull", was reduce, special machining aluminum. In this paper, the evalution of segmented grinding wheel is based on the cutting performance. η is defined as a ratio between the discontinued regions and the of the grinding wheel’s working surface. There were five newly developed grinding wheels with (10.91%, 16.37%, 18.19%, 20.01% and 21.83% respectively) and one conventional η different η = 0%) were used to grind unhardened steel, hardened steel and aluminum. The results showed η grinding wheel (that segmented grinding wheels obtained a smoother surface in compared with conventional η = 20,01% for machining unhardened steel and at η = 18,19% machining aluminum material. On the other hand, segmented wheels with a less number of abrasive grains, show a higher efficiency for obtaining the smoother surface roughness than conventional wheels in the same working conditions. However, the mechanism of machining hardened and aluminum materials is a little bit different.В статье рассматриваются сегментированные шлифовальные круги, разработанные недавно во Вьетнаме с опорой на основы прерывистой механической обработки, с целью повышения шлифующей способности зерен. Явление "засаливания" шлифовального круга, возникающее при налипании шлифованной стружки в межзеренном пространстве, при использовании таких кругов уменьшается, особенно при обработке алюминия. Исследовались круги с различным соотношением прерывистых участков и рабочей поверхности круга. Испытания кругов проводились для алюминиевого сплава, а также закаленной и незакаленной стали при различных режимах обработки, при этом выявлены некоторые отличия в механизме механической обработки

Factors Affecting the Perception of Happiness among Teachers in Vietnam

Vietnam is in the process of implementing education reforms in which teachers play a crucial role in determining success. This study aims to identify the main factors influencing the perception of happiness at work of Vietnamese teachers during the period of educational reform. In any period, teachers are always considered as being the force behind the success of education. Therefore, teachers' happiness is the most vital factor to be taken into consideration when educating students. Identifying the factors that affect teachers' happiness at work is the key to improving their teaching quality and quality of life. This study was conducted to investigate the factors affecting the perceived happiness of secondary school teachers in Vietnam today, thereby objectively assessing the emotional status of teachers in Vietnam in relation to the work they are doing. The results are as follows: 1) Teachers face a lot of pressure from many sides; 2) There is still a large percentage of teachers who do not really attach importance to the teaching profession; 3) State policies have not helped teachers feel secure in their professional activities; 4) Teacher capacity still needs to be greatly improved; 5) It is necessary to strengthen the connection between teachers, educational leaders, policy makers, school administrators and colleagues. This study uses descriptive statistics to present the research results. The survey was carried out in September 2021

ENGLISH TEACHERS’ QUESTIONS IN A VIETNAMESE HIGH SCHOOL READING CLASSROOM

Recently, developing students’ thinking, especially critical thinking (CT), has become a hot issue. Critical thinking has been claimed to have an important impact on learners’ reading comprehension because it can help them analyze, evaluate, construct their thinking, solving problems and reasoning (Ennis, 1989). However, the extent that teachers’ classroom activities contribute to developing students’ critical thinking has rarely been researched. The current case study was conducted with six EFL high school teachers and 10 reading lessons in Vietnam to explore the teachers’ use of questions and to analyze if these questions could facilitate the students’ critical thinking. Classroom observations and the cognitive domain of Bloom’s taxonomy were adapted as the research instruments. The study results reveal common types of questions are often used by high school teachers in their reading lessons. Suggestions are made on types of questions that teachers should function more in their class in order to enhance students’ critical thinking

ENGLISH TEACHERS’ QUESTIONS IN A VIETNAMESE HIGH SCHOOL READING CLASSROOM

Recently, developing students’ thinking, especially critical thinking (CT), has become a hot issue. Critical thinking has been claimed to have an important impact on learners’ reading comprehension because it can help them analyze, evaluate, construct their thinking, solving problems and reasoning (Ennis, 1989). However, the extent that teachers’ classroom activities contribute to developing students’ critical thinking has rarely been researched. The current case study was conducted with six EFL high school teachers and 10 reading lessons in Vietnam to explore the teachers’ use of questions and to analyze if these questions could facilitate the students’ critical thinking. Classroom observations and the cognitive domain of Bloom’s taxonomy were adapted as the research instruments. The study results reveal common types of questions are often used by high school teachers in their reading lessons. Suggestions are made on types of questions that teachers should function more in their class in order to enhance students’ critical thinking

The Current Status of Secondary School Teacher’s Perception of Happiness in Nam Dinh Province during the Implementation Period of the 2018 General Education Program

In the current context of a major revolution in the Vietnamese education system, teachers’ perception of happiness makes an important criterion in evaluating effectiveness of the changes made to educational programs. The initial investigation of the positive effects of this renovation was conducted on the scale of Nam Dinh province and the results show multidimensional sources of information. In addition to positive information, there is still information that raises many questions for leaders to pay attention to. The outcome of the investigation suggests the evaluation of “The job is meaningful” is 3.10 out of 5 points, which is the lowest in assessment criteria. Meanwhile, the rates for “Completely disbelieve” and “Slightly disbelieve” in happiness of their profession in the future take up a large proportion (24.4%). However, other criteria namely “Being satisfied with current position” and “Feeling motivated with the job” received higher evaluation scores, respectively 4.05/5 points and 4.11/5 points. Via the results of the research, the author is looking forward to appropriate actions taken by the Ministry of Education and Training of Vietnam with a view to enhancing the perception of happiness among teachers

Alcohol-Dependent Inpatients in Northern Vietnam : A Follow-Up Study on Relapse and Co-Occurring Psychiatric Disorders

Background: The prevalence of alcohol dependence has been increasing in several countries in the world as well as in Vietnam. This study aims to describe relapse among alcohol-dependent inpatients in Northern Vietnam and some co-occurring psychiatric disorders in these patients. Methods: This study followed 53 alcohol-dependent patients who were treated for six months at the Vietnam National Institute of Mental Health. At the point of one month, three months, and six months after being discharged from the hospital, the patients were monitored for their alcohol consumption, relapse into alcohol dependence, and co-occurring psychiatric disorders by clinical psychiatrists, using the International Classification of Diseases, the 10th edition, Hamilton depression rating scale, Hamilton anxiety rating scale, Pittsburgh Sleep Quality Index, and the EQ-5D-5L Life Quality Assessment. Results: The prevalence of relapse into alcohol dependence was 81.1%. The highest relapse rate was found in the first month after alcohol withdrawal (46.5%), then it decreased gradually. 53.9% of the relapsed patients had at least four alcohol withdrawals; they mainly used home-brewed alcohol. The average daily alcohol intake was fairly high: 14.4 ± 8.5 standard drinks. Mental disorders such as depression, anxiety, and sleep disorder were very prevalent among patients with relapsed alcohol dependence. Conclusions: The rate of relapsed alcohol dependence in Northern Vietnam was very high. It is important to detect and treat psychiatric disorders simultaneously with alcohol dependence to achieve better treatment effectiveness and reduce relapse rates

Adsorptive removal of Pb (II) using exfoliated graphite adsorbent:influence of experimental conditions and magnetic CoFe2O4 decoration

The worm-like exfoliated graphite (EG) based adsorbents prepared from low-cost natural graphite flakes via facile synthesis processes have been found to be efficient adsorbents when it comes to removing Pb (II) from aqueous solution. EG was fabricated by chemical intercalation and microwave assisted exfoliation. Furthermore, the magnetic exfoliated graphite (MEG) was developed by incorporating CoFe2O4 particles into the EG layers using the citric acid based sol-gel technique. Adsorption behaviour of Pb (II) on the as-prepared adsorbents was investigated by taking several experimental conditions into consideration such as contact time, initial concentration, adsorbent dosage, and pH value. The results with initial neutral pH indicated that the adsorption isotherms for Pb (II) on the EG and MEG were well consistent with the Langmuir isotherm model revealing the maximum adsorption capacity of 106 mg/g and 68 mg/g for EG and MEG, respectively. The adsorption kinetics of Pb (II) was found to adhere to the pseudo-second-order kinetic model. The chemical interaction between ? electrons on graphite sheets and Pb (II) ions was suggested to play an essential role in the adsorption mechanism. The introduction of magnetic CoFe2O4 to the EG was found to induce the shift of optimal pH value to a more basic condition. The characterization of the adsorbents was performed using relevant analysis techniques such as Scanning electron microscope (SEM), X–ray powder diffraction (XRD), vibrating-sample magnetometer (VSM), and Fourier-transform infrared (FTIR). The results of this work suggest a high possibility for application of the as-prepared modified graphite to remove hazardous substances in practical wastewater treatment systems. ABSTRAK:  Penyerap Pengelupas Grafit (EG) yang berupa seperti cacing dihasilkan dari grafit semulajadi yang murah melalui proses sintesis serpihan, ia juga merupakan penyerap yang bagus dalam mengasingkan Pb (II) daripada larutan akues. EG direka dengan tindak balas interkalasi kimia dan pengelupasan melalui gelombang mikro. Tambahan, pengelupas grafit magnet (MEG) telah dihasilkan dengan memasukkan zarah CoFe2O4 ke dalam lapisan EG menggunakan teknik sol-gel yang berasaskan asid sitrik. Tindak balas penyerapan Pb (II) pada penyerap yang disiapkan ini, dikaji dengan mengambil kira beberapa keadaan eksperimen seperti waktu disentuh, konsentrasi awal, dos penyerap dan nilai pH.  Hasil keputusan pH neutral awal menunjukkan bahawa isoterm penyerapan bagi Pb (II) pada EG dan MEG adalah konsisten dengan model isoterm Langmuir. Ini menunjukkan kapasiti penyerapan maksimum 106 mg/g dan 68 mg/g bagi EG dan MEG, masing-masing. Penyerapan kinetik Pb (II) didapati mematuhi model kinetik pesudo-order-kedua. Interaksi kimia antara elektron ? pada helaian grafit dan ion Pb (II) memainkan peranan penting dalam mekanisme penyerapan. Pengenalan magnet CoFe2O4 kepada EG didapati telah mengubah nilai pH optimum kepada keadaan asal. Pengelasan penyerapan dilakukan menggunakan teknik analisis yang relevan seperti Mikroskop Elektron Pengimbasan (SEM), Difraksi Serbuk sinar-X (XRD), Magnetometer Sampel-Getaran (VSM) dan Inframerah Perubahan-Fourier (FTIR). Hasil kerja ini mencadangkan kemungkinan besar bagi penggunaan grafit ubah suai yang disediakan bagi membuang bahan berbahaya dalam sistem rawatan air sisa praktikal

Vietnam’s Scientific Publications in the Period of COVID-19

The COVID-19 pandemic is considered a global disaster that affects all areas of the world; however, it is also seen as a motivation for domestic and foreign scientists to focus on researching solutions to reduce its damage. This article aims to explore the correlation of scientific publications of countries in Southeast Asia, among research fields in Vietnam and among topics published by Vietnamese educational institutions in the context of a pandemic. 1392 Southeast Asian countries’ publications related to COVID-19 were referenced from the Scopus database, including 123 articles from Vietnam (up to August 27th, 2020). Statistics show that Vietnam ranks fifth in the number of scientific publications with research cooperation of researchers from 20 different countries. Regarding the research fields of Vietnam, medicine is the main research topic, social science ranks third following environmental science. In the field of social science, articles focus on four key topics: epidemic prevention, reduction of pandemic effects on life and socioeconomics, factors related to online learning of students, healthcare for the elderly. From the analysis results, the authors recommend that researchers should pay attention to other topics in the social sciences that have not been published, such as psychological effects of infected or suspected nCovi, the impact of COVID-19 to disadvantaged groups in society..