Effects of Mg Al Alloy Powder on the Combustion and Infrared Emission Characteristics of the Mg Al PTFE Viton Composition

Metal-Fluorocarbon compositions are the pyrotechnic formulations which have been widely used in infrared decoy flares to protect aerial targets from infrared guide missile seekers. In this work, the effect of Mg-Al alloy powder (i.e. the particle size and the content) on the combustion and the infrared emission characteristics (i.e. the infrared emission distribution and the infrared radiance) of the pyrotechnic composition based on Mg-Al alloy, polytetrafluoroethylene (PTFE) and Viton rubber are described. The results show that the high burning rate (with the values of 4.0 mm.s-1 to 10.0 mm.s-1, depend on the compression density) of this composition is achieved with a high content of Mg-Al alloy or when using fine Mg-Al alloy particles as well as coarse PTFE particles. On the other hand, the infrared emission radiance (in the wavelength range of 2.5 μm to 5.0 μm) of Mg-Al/PTFE/Viton composition reaches maximum values (i.e. 17.7 W.cm-2.Sr-1 and 21.0 W.cm-2.Sr-1 with the size of Mg-Al particles are 20 μm and 120 μm, respectively) at 60 wt% Mg-Al alloy. Finally, the Mg-Al/PTFE/Viton composition has a similar combustion and emission characteristics as the Mg/PTFE/Viton composition

How scientific research changes the Vietnamese higher education landscape: Evidence from social sciences and humanities between 2008 and 2019

Background: In the context of globalization, Vietnamese universities, whose primary function is teaching, there is a need to improve research performance. Methods: Based on SSHPA data, an exclusive database of Vietnamese social sciences and humanities researchers’ productivity, between 2008 and 2019 period, this study analyzes the research output of Vietnamese universities in the field of social sciences and humanities. Results: Vietnamese universities have been steadily producing a high volume of publications in the 2008-2019 period, with a peak of 598 articles in 2019. Moreover, many private universities and institutions are also joining the publication race, pushing competitiveness in the country. Conclusions: Solutions to improve both quantity and quality of Vietnamese universities’ research practice in the context of the industrial revolution 4.0 could be applying international criteria in Vietnamese higher education, developing scientific and critical thinking for general and STEM education, and promoting science communication

Trichinellosis in Vietnam

Trichinellosis is a zoonotic parasitic disease with a worldwide distribution. The aim of this work was to describe the epidemiological and clinical data of five outbreaks of trichinellosis, which affected ethnic minorities living in remote mountainous areas of northwestern Vietnam from 1970 to 2012. Trichinellosis was diagnosed in 126 patients, of which 11 (8.7%) were hospitalized and 8 (6.3%) died. All infected people had consumed raw pork from backyard and roaming pigs or wild boar at wedding, funeral, or New Year parties. The short incubation period (average of 9.5 days), the severity of the symptoms, which were characterized by diarrhea, abdominal pain, fever, myalgia, edema, weight loss, itch, and lisping, and the high mortality, suggest that patients had ingested a high number of larvae. The larval burden in pigs examined in one of the outbreaks ranged from 70 to 879 larvae/g. These larvae and those collected from a muscle biopsy taken from a patient from the 2012 outbreak were identified as Trichinella spiralis. Data presented in this work show that the northern regions of Vietnam are endemic areas for Trichinella infections in domestic pigs and humans

THE EFL 9TH GRADERS’ ATTITUDES TOWARD THE USE OF VISUAL AIDS IN READING COMPREHENSION AT A SECONDARY SCHOOL IN KIEN GIANG, VIETNAM

Reading skill is an essential component of language acquisition since it aids in the development of other associated skills. Therefore, how to improve students' reading is always the primary concern of most secondary school teachers of English. Besides, thanks to the visual aids, teachers have been able to design many interesting and lively reading lessons. Therefore, this study aimed to explore the students’ attitudes toward the use of visual aids in reading comprehension. The participants were 45 students from grade 9 at a secondary school in Kien Giang province. This study was conducted as a quantitative research approach. Data collection was from questionnaires. The finding of the study indicated that there was a good correlation between visual aids and reading comprehension. Most of the participants had positive attitudes toward the use of visual aids in reading comprehension.  Article visualizations

Factors Affecting Successful Quality Assurance Implementation in Vietnamese Higher Education: A Qualitative Study

Quality assurance and accreditation was officially introduced into the higher education system in Vietnam over ten years ago. It is evident that quality assurance has resulted in positive impacts on university management, teaching, learning and research activities. This paper aims to explore factors that aid the successful implementation of higher education quality assurance and accreditation in Vietnam. Through semi-structured interviews with 32 participants, this study identified a number of factors that contributed to quality assurance processes, including awareness of the importance of quality assurance, better institutional manager leadership, support of university lecturers, staff, and students, and the vital responsibility of internal quality assurance staff. These confirm that internal stakeholders play an important role in undertaking quality assurance programmes and activities

NUMERICAL SIMULATION OF THE BULK FORMING PROCESS TO MANUFACTURE COUPLING DETAILS FROM TUBE BILLET

Currently, most coupling details in the actuators are made by traditional methods such as bulk forming from block billet and then metal cutting. Such manufacturing methods often lead to material wastes due to cutting a large amount of excess processing. To save material and improve production efficiency, tube billet would be selected for bulk forming. However, when tube billet is used for bulk forming, it should be carefully calculated to avoid instability and folding defects in workpiece. This article presents the research on the forming process of the coupling details using numerical simulation and based on the obtained results, the suitable geometric size of tube billet for the forming operation in closed die can be determined

FACTORS INFLUENCING THE INTENTION TO USE MOBILE MONEY: A STUDY IN BUSINESSES IN HANOI, VIETNAM

Abstract The government's and people's expectations for the successful implementation of this activity are significant, but the scientific basis for its implementation remains limited. This study, the first of its kind in Vietnam since the aforementioned decision, aims to clarify the factors influencing consumer usage of Mobile Money, focusing on businesses in Hanoi, Vietnam. Mobile Money, a form of mobile wallet not linked to bank accounts, represents a new transaction method in Vietnam, catering to consumers' reduced use of cash. This research examines the factors affecting the intention to use Mobile Money among employees of businesses in Hanoi. To achieve this goal, the author relies on the Theory of Reasoned Action (TRA), the Theory of Planned Behavior (TPB), the Technology Acceptance Model (TAM), and risk perception variables to design the research model. With a sample of 479 employees who intend to use Mobile Money, hypotheses are tested using a multivariate regression model through quantitative analysis with IBM SPSS Statistics 20.0. The research results identify five factors that positively influence the intention to use Mobile Money: Perceived Ease of Use, Trust, Security and Privacy, Social Influence, and COVID-19 Risk Perception. The factor of Perceived Usefulness does not have a significant impact in this case. Particularly, heightened risk perception regarding COVID-19 or social instability leads to an increased intention to use Mobile Money. This study provides guidance to Mobile Money service providers on how to enhance users' intention to use their services. Additionally, it underscores how factors related to diseases or societal instability can alter or even disrupt initial intention or behavior models

STUDY ON ANTIOXIDANT ACTIVITIES OF THE AERIAL PARTS AND SOME COMPOUNDS ISOLATED FROM Archidendron clypearia ((Jack) I. Niels Part 2. ISOLATING, DETERMINING STRUCTURE AND ANTIOXIDANT CAPABILITY OF SOME COMPOUNDS FROM ETHYL ACETATE EXTRACT

The antioxidant activity in vitro of methanol extract of Archidendron clypearia was evaluated by in vitro tests on isolated liver cells of mouses with ED50 value ​​ of 2.18 μg/mL compared to that of curcumin of 1.87 µg/mL. Using combined chromatographic methods, four compounds were isolated from chloroform extract of the Archidendron clypearia. Their structures were elucidated to be daucosterol, 1-octacosanol, docosenoic acid, and methyl gallate by 1D- and 2D-NMR spectroscopic methods and in comparison with those reported in the literature. This is the first report of these compounds from the plant. All four compounds showed quite high antioxidant activity, for which methyl gallate was the highest one

U-Pb zircon age of granitogneiss of the Dai Loc complex and their geological significances

Dai Loc granitoid complex located to the north of Kon Tum massif. It is composed of porphyric biotite granitogneiss, two mica granitogneis, granodiorite gneiss and granite migmatite. Rock forming minerals include mainly K-feldspar, Na rich plagioclase, quartz and biotite.Zircons separated from two granitogneiss samples (DLT 02 and DLT 07) collected in the Dai Loc complex were analyzed for U and Pb isotopic compositions using an LA-ICP-MS to determine the protolith ages of the complex. Data acquired from thirty-nine zircon grains provide concordant ages concentrated at 427-423 Ma (weighted mean), indicating that the protolith age of the granitogneiss (age of primary magma crystallization) is late Silurian.ReferencesA. Carter, D. Roque, C. Bristow, P. Kinny, 2001: Understanding Mesozoic accretion in Southeast Asia: Significance of Triassic thermotectonism (Indosinian orogeny) in Vietnam. Geology, 29(3), 211-214. D.J. Cherniak et al., 1997: Rare - earth diffu-sion in zircon. Chemical Geology, 134, 289-301. F. Corfu, J. M. Hanchar, P.W. Hoskin P. Kinny, 2003: Atlas of zircon textures. Reviews in mineralogy and geochemistry, 53(1), 469-500. M.H. Dodson, 1973: Closere temperature in cooling geochronological and petrological systems. Contrib. Mineral. Petrol. 40, 259-274. T.M. Harrison, R.L. Armstrong, G.K.C. Clarke, 1978: Thermal models and cooling histories from fission-track, K-Ar, Rb/Sr and U/Pb mineral dates, Northern Coast Pluton Complex British Colombia abstract. In: Short Papers of the Fourth International Conference on Geochronology, Cosmochoronology, Isotope Geology. U.S. Geol. Surv., Open File Rep., 167-170. T.M. Harrison et al., 1979 : Geochronology and thermal history of coast plutonic complex, near Prince Rupert, British Columbia. Can.J. Earth Sce. 16, 400- 410. Phạm Trung Hiếu và nnk, 2009: Tuổi đồng vị U-Pb zircon trong granit phức hệ Yê Yên Sun Tây Bắc Việt Nam và ý nghĩa của nó. Tc. Các Khoa học về Trái Đất, T.31, (1), 23-29. Pham Trung Hieu et al., 2015: Late Permian to Early Triassic crustal evolution of the Kontum massif, central Vietnam: zircon U-Pb ages and geochemical and Nd-Hf isotopic composition of the Hai Van granitoid complex. International Geology Review, inpress. P.D. Kinny et al., 1990: Age constraints on the geological evolution of the Narryer Gneiss Complex, Western Australia: Australia Journal of Earth Sciences, 37, 51-69.. C-Y. Lan et al., 2003: Geochemical and Sr-Nd isotopic constraints from the Kontum massif, Central Vietnam on the crustal evolution of the Indochina block, Precam. Res., 122, 7-27. C. Lepvrier et al., 1997: 40Ar/ 39Ar Indosinian age of NW trending dextral shear zones within the Truong Son belt (Vietnam): Cretaceous to Cenozoic overprinting. Tectonophysics, 283, 105-127. Nguyễn Quang Luật, Phạm Trung Hiếu, Nguyễn Tiến Thành, 2012: Tuổi U-Pb zircon và thành phần đồng vị Hf của gabrodiorit khối A-Bung, vùng Đăk Krông - A Lưới. Tạp chí Địa chất, A329, 19-29. E.A. Nagy, H. Maluski, C. Lepvrier et al., 2001: Geodynamic significance of the Kontum Massif in Central Vietnam: Composite 40Ar/39Ar and U-Pb ages from Paleozoic to Triassic, J. Geol., 109, 755-770. Tran Ngoc Nam, 1998: Thermotectonic events from early Proterozoic to Miocene in the Indochina craton: implication of K-Ar ages in Vietnam. J. Asian Earth Sci., 16, 475-484. Trần Ngọc Nam, 2004: Tuổi đồng vị U-Pb của zircon 436 triệu năm trong phức hệ Sông Re ở địa khối Kon Tum và ý nghĩa của nó, Tạp chí Địa chất, A281, 18-23. Trần Ngọc Nam và nnk, 2004: Biến chất nhiệt độ siêu cao Permi-Trias: Va chạm lục địa ở địa khối Kon Tum? TC Địa chất, A285,1-8. Tạ Trọng Thắng, 1998: Tuổi và đặc điểm biến dạng của đới cắt trượt biến dạng dẻo Đà Nẵng - A Lưới - Khe Sanh. TC Địa chất, A245, 81-89. Đào Đình Thục, Huỳnh Trung, 1995: Địa chất Việt Nam. Tập II. Magma. Cục Địa chất Việt Nam. Hà Nội, 359 tr. Trần Văn Trị, Vũ Khúc (đồng chủ biên), 2009: Địa chất và Tài nguyên Việt Nam. Nxb. Khoa học Tự nhiên và Công nghệ, Hà Nội, 390tr. T. Usuki, C. Y. Lan, T. F. Yui, 2009: Early Paleozoic medium-pressure metamorphism in central Vietnam: evidence from Shirmp U-Pb zircon ages. Geosciences Journal, 13(3): 245-256. I.S. Williams and S.Claesson, 1987: Isotopic evidence for the Precambrian provenance and Caledonian metamorphism of high grade paragneisses from the Seve Nappes, Scandinavian Caledonides: II. Ion microprobe zircon U-Th-Pb: Contribution to Mineralogy and Petrology, 97, 205-217. X. H. Zhou, 2003: My thinking about granite genses of South China. Geological Journal of China Universityies, 9 (4): 556-565 (in Chinese with English abstract). Nguyễn Văn Vượng, Vũ Văn Tích, Hansen Bent. 2004: Áp dụng phương pháp Tims U/Pb xác định tuổi kết tinh của khối Đại Lộc. TC Khoa học về Trái Đất, T.26, (3), 202-207.