TẠP CHÍ KHOA HỌC TRƯỜNG ĐẠI HỌC TRÀ VINH

Glass ionomer cement (GIC), a thermoplastic polymer, is toughed by ionic bonding is used in dentistry as a filling material. The glass-powder used has some disadvantages such as: poor strength and toughness, and instability in water. Therefore, the aim of this work is to enhance mechanical and fluoride release properties of the GICs by modifying ingredients. The results show that the compressive strength reached to from 60.5 to 86.2 MPa, the setting time met the ISO 9917-1:2007 quality standard. This also suggests that, in addition to 35% PAA in water with Mw of 100,000, 5% of Maleic acid and 5% Tartaric acid to produce GIC which can be used as suitable materials for improving its fluoride ion release over 28 days. The average diameter (dmean) of glass powder for GICs was 14.3 mm; S.P. Surface area was 10,358 cm2=cm3, improvement of liquid composition includes 35% PAA in water with Mw of 100,000, 5% of Maleic acid and 5% Tartaric acid. The compressive strength after curing 28-day reaches from 60.5 to 86.2 MPa and the setting time responds with ISO 9917-1:2007. In conclusion, it was found that the GIC can release fluoride ions (F-) for the during of the examination period.

The aim of this study was to develop the technological process of making herbal tea bags from orange peels. In order to achieve this purpose, the effects of blanching, drying conditions, and mixing ratio of orange peels,green tea, and stevia were examined. The results showed that orange peel blanched in hot water at 80oC for 6 minutes helps to retain the green color and has high sensory value. Upon being dried at 70oC for 210 minutes, the total polyphenol content is 420.69 mg GAE/g dry weight with a final moisture content of 9%. With the mixing ratio of 70% orange peel, 25% green tea, and 5% stevia, the product has the highest sensory value-specifically color (3.84), flavors (4.07), tastes (3.61), and sweetness (3.92) -and with total polyphenols of 516.51 mgGAE/g dry matter and antioxidant activity of 119.18%.

The research was conducted to determine the effects of psychological capital on the personality on hotel staff working in an engagement setting in Ho Chi Minh City, Viet Nam. Data was collected by surveying 378 staffs who are working in hotels in Ho Chi Minh City which are rated 3 stars or more. Descriptive analysis, exploratory factor analysis, and linear regression analysis were used with SPSS 20 statistical package for data analysis. The results show that all psychological capital factors, including hope, efficacy, resilience and optimism have hadpositive impacts on hotel staffs’ work ethic. The study also demonstrated the effects of personality on the hotel staffs’ engagement with their work. The research outcomes suggest some managerial solutions to management problems by adapting psychological capital data and to take into consideration the personality of staff to enhance employees  working in engagement settings in Ho Chi Minh City.

Yogurt is a food product fermented from milk by Streptococcus thermophilus (S. thermophilus) and Lactobacillus bulgaricus (L. bulgaricus), which is very good for health. This study focuses on the evaluation of the ratio of condensed milk / Non-sugar fresh milk from 1/1.5 - 1/2 - 1/2.5, the ratio of the puree of soursop pulp added (5-25%), the fermentation temperature (from 41 to 47 oC) and fermentation time (from 6 to 8 hours) on the fermentation ability of yogurt in order toidentify the suitable fermentation condition for producing yogurt with the best sensory quality and the suitable sour taste. Additionally, this study also  investigates the effect of temperature and time of the fermentation process on the quality of yogurt. The results showed that, with the ratio of condensed milk / Non-sugar fresh milk = 1/2, the sensory properties of yogurt were very good. Besides, with the added puree of 5% and fermentation temperature of 44 oC within 7 hours, the sensory quality of yogurt was the best (with the point of 4.7/5 by the quality description scale) and the Donic degree of the product reached 86.3 that was suitable for yogurt (70 to 90 oD)

The study aimed to investigate the effects of drying temperature and time on quality of dried dragon fruit peel. The experiment was arranged with 02 factors (the drying temperatures of 45oC, 50oC, 55oC, 60oC and drying time of 2 hours, 3 hours, 4 hours, 5 hours), 04 levels and  03 repetitions. The evaluated criteria include: moisture, total polyphenol content, anthocyanin, antioxidant activity, and sensory evaluation of the product. The results showed that at 50oC for 3 hours, polyphenols total content was 2578 mgGAE/100g dry matter, antioxidant activity was 29.76%, anthocyanin content 0.46%, high Sensory evaluation scores for colour (5.80), flavour (5.87), taste (6.17) and texture (6.22).

This research is conducted to assess the economic efficiency of two farming operations of goats called intensive and semi-intensive in Duyen Hai District, TraVinh Province, thereby finding out the drawbacks of each system and potential solutions towards the sustainability of goat farming in the area. An in-depth interview method was applied (KIP) to inteview two different groups of participants. The first group was leaders of Department of Agriculture and Rural Development of TraVinh Province and the second group consisted of 120 household farmers in four communes of Duyen Hai District. Beside, multivariate regression model is also applied in this study. The findings show that both systems offer a great deal of productivity (VND 113.27mil/year/household for semi-intensive farming system and VND 136.11 mil/year/household for intensive farming system). However, in response to climate change, the intensive goat farming operation brings higher level of profits and has a lower environmental impact, especially goat manure is beneficial for crops.

Experimental competency is one of the specialized capabilities, important to be conceived and developed in the process of teaching physics. In this article we  present how to use selfcreated experiments to assess the studying results in relevance to the experimental competency development for students in teaching physics in high school.

Sludge of seafood processing factories discharged directly into the environment can lead to environmental pollution. Research on the use of seafood processing sludge as compost for agriculture in the Mekong Delta is encouraged. The objectives of this study were (1) to evaluate the chemical composition of seafood processingsludge after 60 days composting and (2) to evaluate the growth of Tagetes patula L planted with composted sludge. The sludge composting experiment was carried out with 3 treatments: sludge + Trichoderma fungi; sludge + chicken manure + Trichoderma fungi; sludge + straw + chicken manure + Trichoderma fungi. The results showed that the treatment of sludge + straw + chicken manure + Trichoderma fungi had a betterquality than the other two treatments. The pH, TC, TN, NH+ 4 , NO- 3 , TP, PO3 4- and heavy metal(Pb, Cd, Cr, Cu, Ni, Zn and Hg) contents of sludge meet the environmental standard of Viet Nam (10TCN526:2002). E. coli and Salmonella were not present at the end of the composting experiment. Tagetes patula L grew and flowered on all 4 treatments: control – composted straw; sludge + Trichoderma fungi; sludge + chicken manure + Trichoderma fungi; sludge + straw + chicken manure + Trichoderma fungi. However,Tagetes patula L grew best on the sludge + Trichoderma fungi experimental condition .

On the one hand, the adoption of managerial accounting in business is determined by corporate governance; on the other hand, it is also dependent on business environment and firm characteristic. Nonetheless, so far the causal relationships from corporate governance, business environment and firm characteristic to the adoption of managerial accounting in business  have not been empirically explored in Vietnam. This research is conducted to investigate the simultaneous effects of corporate governance, business environment and firm characteristic on the adoption of managerial accounting in business. This study employs  reliability analysis, exploratory factor analysis and regression analysis to deal with the data. The findings indicate that, corporate governance, business environment and firm characteristic concurrently affect the adoption of managerial accounting in business.

The aim of the study was to identify factors that could affect the quality of pond apple (Annona glabra L.) jam.Various quality parameters were investigated with three replica groups for each: added fruit flesh compared to juice/water solution (30%; 35%; 40%; 45%; 50%), soluble solid concentration of juice (45; 50; 55) and varying pH levels (3.0; 3.2; 3.4). The results showed that when the added fruit flesh to juice/water was 40%, the product produced a high-value bright yellow, corresponding to CIELAB color space values, L∗, a∗, b∗, 12.45; 0.58; 8.56 and the jam product gained the highest scores from the sensory panel, which was demonstrated by perceptive color (5.05), flavor (4.98), taste (5.22) and texture (5.12). With a pH of 3.2 and a sugar concentration of 55%, the product with 40% added fruit flesh has the highest sensory value in terms of color, odor, taste and texture.