The Study of Optimal Molding of a LED Lens with Grey Relational Analysis and Molding Simulation

Injection molding technology is known as the most widely used method in mass production of plastic products. To meet the quality requirements, a lot of methods were applied in optimization of injection molding process parameter. In this study the optimization based on Taguchi orthogonal array and Grey relational analysis (GRA) is used to optimize the injection molding process parameters on a LED lens. The four process parameters are: packing pressure, injection speed, melt temperature and mold temperature. The multi-response quality characteristics are total displacement, volumetric shrinkage, and thermal residual stress. The optimal molding parameters are packing pressure (90 MPa), injection speed (300 mm/sec), melt temperature (270 °C) and mold temperature (90 °C). The luminous uniformity of the LED is 92.61 % and the viewing angle of the LED is 124.76°. Among the four factors, packing pressure plays the key role in reducing total displacement, volumetric shrinkage, and thermal residual stress

Hyper-production of raw-starch-digesting enzyme by mutant fungal strain and optimisation of solid by-products: Research article

Selected fungal strain for production of raw-starch-digesting enzyme by solid state fermentation was improved by sequential exposures to γ-irradiation of Co60, ultraviolet and treatments with Nmethyl-N'-nitrosoguanidine. Mutant Aspergillus sp. CXN2-3A was chosen and its production of raw-starch-digesting enzyme (RSDE) was improved 2 folds higher than that of wild type. Optimal condition for the production of the enzyme using wheat bran as the substrate was accomplished for the CXN2-3A. With the optimal fermentation condition and the solid medium supplemented with urea and NH4NO3, CoSO4, Tween 80, 1% glucose, CXN2-3A produced RSDE 19.23 folds higher than wild type cultured in pre-optimized condition and un-supplemented medium.Chủng nấm chọn lọc sản xuất enzyme thủy phân tinh bột bằng cách lên men trạng thái rắn, chủng nấm được cải thiện bằng chiếu xạ tia cực tím, tia Co60 và các phương pháp xử lí với N-methyl-N'-nitrosoguanidine. Mutant Aspergillus sp. CXN2-3A, đã được lựa chọn để sản xuất enzyme (RSDE) thủy phân tinh bột sống cải thiện cao hơn 2 lần so với chủng dại. Điều kiện tối ưu cho việc sản xuất các enzyme bằng cách sử dụng cám, lúa mì đã được thực hiện cho CXN2-3A. Với điều kiện lên men xốp tối ưu và bổ sung urê và NH4NO3, CoSO4, Tween 80, 1% glucose, CXN2-3A đã sản xuất RSDE cao gấp 19,23 lần so với kiểu dại ở cùng điều kiện

An Exploration in Social and Emotional Health of Vietnamese High School Students

Social and emotional health (SEH) aims to promote academic success and create school well-being. SEH has not been studied in Vietnam. This article focused on exploring the SEH of Vietnamese high school students because of the high-risk level in mental health that appeared in this group. The study was carried out using a qualitative case study approach to interviewing 74 students, 12 teachers, 7 school administrators, and 4 school counselors. We interpreted four features of SEH\u27s expression of Vietnamese students: (1) Confident but lack of individual perspectives, (2) Respectful but lack of listening and empathy in school relationships, (3) Balanced but lack of authentic perception of emotions and effective emotional management, (4) Satisfied but lack of sustainability and action. This study has broadened our understanding of external behaviours and current limitations in the young people’s SEH from their perspectives in a developing Southeast Asian country to promote positive psychological development in school-based prevention programs

The Study of Optimal Molding of a LED Lens with Grey Relational Analysis and Molding Simulation

Injection molding technology is known as the most widely used method in mass production of plastic products. To meet the quality requirements, a lot of methods were applied in optimization of injection molding process parameter. In this study the optimization based on Taguchi orthogonal array and Grey relational analysis (GRA) is used to optimize the injection molding process parameters on a LED lens. The four process parameters are: packing pressure, injection speed, melt temperature and mold temperature. The multiresponse quality characteristics are total displacement, volumetric shrinkage, and thermal residual stress. The optimal molding parameters are packing pressure (90 MPa), injection speed (300 mm/sec), melt temperature (270 °C) and mold temperature (90 °C). The luminous uniformity of the LED is 92.61 % and the viewing angle of the LED is 124.76°. Among the four factors, packing pressure plays the key role in reducing total displacement, volumetric shrinkage, and thermal residual stress

Preschool STEM Activities and Associated Outcomes: A Scoping Review

This review highlights the need for further investigation into the benefits of STEM activities in preschool children’s learning, girls’ engagement and learning of children with disabilities in the STEM field. The review process involved accessing 19 relevant studies from Scopus, ERIC and Google Scholar databases in March 2023. Through the synthesis of information from these studies, seven STEM activities were identified as effective in enhancing preschool children’s learning: educational robots, educational games, argumentative interactions, inquiry-based learning and engineering design, drawing and telling about engineers, free play and pretend play, and group membership. Each of these activities contributes to different learning outcomes for children. Moreover, the review emphasizes the importance of role-playing activities ‘as if’ engineers and scientists, facilitated by teachers, in fostering girls’ motivation and engagement in the STEM field from an early age. Long-term scientific interventions at home have a significant positive impact on the science literacy skills of deaf children. The implications of this review are particularly relevant for early childhood educators, as it provides valuable insights into the use of STEM activities to enhance children’s learning outcomes

El trauma de los niños vietnamitas que viven en familias incompletas

Children living in incomplete families have to suffer from more hardships than others including psychological trauma that could never be cured without safe approaches. In this paper, we used the Children Behavior Checklist (CBCL test) by Achenbach to initially filter the incidence of children in incomplete families with psychological trauma, the extent of childhood trauma, and the signs of trauma. Moreover, the Self-esteem scale of Toulouse was also utilized to investigate children's self-esteem and determine the impact of psychological trauma on the self-assessment of children. Based on these tools, the research conducted a correlation analysis of psychological trauma of children in incomplete families through indicators of awareness of, emotions with, and behaviors towards family and social life (self-evaluated by children). The results showed that there are differences in psychological trauma of children in terms of awareness, emotions, and behaviors. The differences allow for a better definition of children's causes, influences, and degrees of psychological trauma. This is the basis for proposing timely filtering solutions and effective psychological support measures for these children. Keywords: correlation analysis; signs of psychological trauma; children; incomplete family; Vietnam.Los niños que viven en familias incompletas tienen que sufrir más dificultades que otros, incluido el trauma psicológico que nunca podría curarse sin enfoques seguros. En este artículo, se utiliza la Lista de Verificación de Comportamiento Infantil (prueba CBCL) de Achenbach para filtrar inicialmente la incidencia de niños en familias incompletas con trauma psicológico, el alcance del trauma infantil y los signos de trauma. Además, la escala de autoestima de Toulouse también se utilizó para investigar la autoestima de los niños y determinar el impacto del trauma psicológico en la autoevaluación de los niños. Con base en estas herramientas, la investigación realizó un análisis de correlación del trauma psicológico de los niños en familias incompletas a través de indicadores de conciencia, emociones y comportamientos hacia la vida familiar y social (autoevaluados por los niños). Los resultados mostraron que existen diferencias en el trauma psicológico de los niños en términos de conciencia, emociones y comportamientos. Las diferencias permiten una mejor definición de las causas, influencias y grados de trauma psicológico de los niños. Esta es la base para proponer soluciones de filtrado oportunas y medidas de apoyo psicológico eficaces para estos niños. Palabras clave: análisis de correlación; signos de trauma psicológico; niños; familia incompleta; Vietnam

Impact of trained human resources, adoption of technology and international standards on the improvement of accounting and auditing activities in the agricultural sector in Viet Nam

Recently, the adoption of accounting and auditing standards in the agricultural sector has been a global phenomenon that has gained increasing trend due to the significant role of the agricultural industry in the country's economy. Thus, the present study examines the impact of trained human resources, technology adoption, and international standards on improving accounting and auditing activities in the agricultural sector in Vietnam. The present research investigates the moderating impact of agricultural, institutional support among the linkage of trained human resources, technology adoption, international standards, and improvement of accounting and auditing activities in the agricultural sector. The present article has adopted the questionnaires to gather the primary data from selected respondents. The current research has applied the smart-PLS to test the study's hypotheses. The results revealed that trained human resources, technology adoption, and international standards positively impact the improvement of accounting and auditing activities in the agricultural sector. The findings also indicated that the agricultural institutional support significantly moderates the linkage of trained human resources, technology adoption, international standards, and improved accounting and auditing activities in the agricultural sector.Nguyen Van Hoa (University of Kinh Bac (UKB)), Nguyen Thi Hanh Duyen (Vinh University), Vu Ngoc Huyen (Viet Nam National University of Agriculture (VNUA)), Hoang Vu Quang (Researcher at Institute of Policy and Strategy for Agriculture and Rural Development (IPSARD)), Nguyen Van Huong (Hung Yen University of Technology and Education (UTEHY)), Nguyen Thi Cam Tu (National Economics University (NEU)), Bui Thi Minh Nguyet (Vietnam National University of Forestry (VNUF))Includes bibliographical references

Application of industrial enzymes in the traditional technology of alcohol from cooked sticky rice in Nam Dinh province, Vietnam

Based on the traditional technology of alcohol from cooked sticky rice in Nam Dinh province, Vietnam, the experiments were conducted by the way to kept the technological process as well as the proportion of ingredients. The quantity of the sticky rice for every experiments was 10 kg. The obtained results showed that the addition of 0.05% enzyme SEBflo-TL compared to the dry matter of sticky rice leads to an increase of the absolute anhydrous alcohol by 10%. Combined application of 0.05% enzyme SEBflo-TL and 0.08% SEBrew-GL for hydrolysing starch and β -glucan, the amount of obtained anhydrous alcohol is 4.6 liters compared to 4.0 liters in the sample control without enzyme application, yield increased by 15% and could provide significant economic benefits to wine producer. In other hand, after the first distillation, the fractional distillation reduced concentration of metanol, acetaldehyde and improved volatile compounds of producted alcohol. The finished alcohol met the Vietnam National technical regulation for alcoholic beverages and are unlikely to cause toxicity to consumers

A Research on the Quality of Public Transportation Services by Bus in Vietnam

This study was conducted to assess the status of the quality of public passenger transport services by bus in Hanoi. Data were collected from regular passengers using buses as a means of transportation in the city, including passengers standing at stations, waiting shelters and on vehicles to make trips and students of some universities who use buses as a means of transportation. We employ descriptive statistics and hierarchical analysis to learn about the topic of research. The results indicate that the quality of public transport services by buses in Hanoi, which was judged by passengers quite well. In particular, the safety level, convenience, security and hygiene is up to 70%, which was higher than the highest quality level. Quality of fast level and reliability are low. Keywords: quality of services, public passenger transport, buses, Vietnam. DOI: 10.7176/RJFA/10-13-04 Publication date:July 31st 201