A Combined Strain Element in Static, Frequency and Buckling Analyses of Laminated Composite Plates and Shells

This paper deals with numerical analyses of laminated composite plate and shell structures using a new four-node quadrilateral flat shell element, namely SQ4C, based on the first-order shear deformation theory (FSDT) and a combined strain strategy. The main notion of the combined strain strategy is based on the combination of the membrane strain and shear strain related to tying points as well as bending strain with respect to cell-based smoothed finite element method. Many desirable characteristics and the enforcement of the SQ4C element are verified and proved through various numerical examples in static, frequency and buckling analyses of laminated composite plate and shell structures. Numerical results and comparison with other reference solutions suggest that the present element is accuracy, efficiency and removal of shear and membrane locking

THE STATUS OF STUDENTS’ POSITIVE QUALITIES IN TABLE TENNIS 1 COURSE AT SAIGON UNIVERSITY, VIETNAM

The purpose of the article is to construct a scale to evaluate the positivity of students in the course Table Tennis 1 at Saigon University, Vietnam. Using common methods in the field of physical education (analysis and synthesis of documents, interviews, statistics). Through reference documents, references and interviews with experts, specialists and lecturers, the article has identified 32 criteria for evaluating the positivity of students in the course Table Tennis 1 at Saigon University. The results of applying 32 evaluation criteria show that the situation of students’ positivity in the course Table Tennis 1 at Saigon University is good in terms of awareness of learning table tennis and the need for positive learning table tennis; average in terms of motivation for positive learning table tennis and positive behavior when learning table tennis; about expressing interest when learning table tennis at a good level according to students and average according to lecturers.  Article visualizations

The application of dual-layer remote phosphor geometry in achieving higher color quality of WLEDs

If remote phosphor structures are put into comparison with conformal phosphor or in-cup phosphor, their luminous flux are better, but the color quality is not as elevated. This leads to an obvious need of a practical solution to enhance color quality. Therefore, many studies were carried out to achieve this purpose, and so is ours. We proposed using two layers of phosphor in WLEDs to achieve better rendering ability and chromatic performance. The identical WLEDs with different color temperatures, 5600 K-8500 K, were used and reported in this paper. Our research consists of two parts, which are placing a layer of red phosphor SrwFxByOz:Eu2+,Sm2+on the yellow YAG:Ce3+ phosphor layer at first, and then specifying an appropriate SrwFxByOz:Eu2+,Sm2+ concentration to reach the highest color performance. It is shown that with the contribution of SrwFxByOz:Eu2+,Sm2+,the color rendering index (CRI) and color quality scale (CQS) are increased. This can be explained by the increased amount of red light components in the WLEDs when the concentration of SrwFxByOz:Eu2+,Sm2+ was greater. However, excessive SrwFxByOz:Eu2+,Sm2+ will cause the reduction in the flux, which has been proven by the application of Mie scattering and the Lambert-Beer law. Therefore, the conclusion will present an optimal amount of SrwFxByOz:Eu2+,Sm2+ to obtain high color quality while minimizing the light loss

Investigation on the application of ZnO nanostructures to improve the optical performance of white light-emitting diodes

Though combining blue LED chips with yellow phosphor has been the most common method in white light-emitting diode (WLED) production, the attained angular correlated color temperature (CCT) uniformity is still poor. Thus, this article proposes to add ZnO nanostructures to WLED packages to promote the color uniformity of the WLEDs. The outcomes of the research demonstrate that utilizing ZnO at different amount can affect the scattering energy and the CCT deviations in WLEDs packages in different extents. Particularly, adding the node-like (N-ZnO), sheet-like (S-ZnO), and rod-like (R-ZnO) leads to the corresponding decreases of CCT deviations from 3455.49 K to 96.30 K, 40.03 K, and 60.09 K, respectively. Meanwhile, with 0.25% N-ZnO, 0.75% S-ZnO, and 0.25 % R-ZnO, WLED devices can achieve both better CCT homogeneity and lower reduction in luminous flux. The results of this article can be a valuable document for the manufacturer to use as reference in improving their WLED products

Effects of yeast extract and methyl jasmonate on the enhancement of solasodine biosynthesis in cell cultures of Solanum hainanense Hance

In this work, the effects of the elicitors methyl jasmonate (MeJA) and yeast extract (YE) on the growth and solasodine production of Solanum hainanense cells were investigated. The results showed that various concentrations of MeJA (50-250 µM) and YE (1-4 g/L) have different eliciting influences. The increase of solasodine content induced by the elicitation of 3 g/L of YE and 50 µM of MeJA at the beginning of cell culture was about 1.9- and 1.3-fold, respectively, as compared with that of the non-elicitated cells. In general, YE (biotic elicitor) was more effective in enhancing solasodine production than MeJA (abiotic elicitor)

Primary Evaluation on Growth Performances of Stress Negative Piétrain Pigs Raised in Hai Phong Province of Vietnam

peer reviewedThe present study was carried out on 19 stress negative Piétrain pigs (Pietrain ReHal), consisting of 13 gilts and 6 young boars imported from Belgium, raised in the livestock farm of Dong Hiep (Hai Phong) in order to evaluate growth performances and their adaptability in the North of Vietnam. Results showed that the average body weight of the whole herd at 2, 4, 5.5, and 8.5 months old was 19.05, 51.05, 85.82, and 119.47 kg, respectively. During the growing periods, except the first stage, the male grew faster than the female and the pigs of the CT genotype grew faster than those of CC genotype although the difference was not significant (P>0.05). The average daily gain (ADG) was 528.56 grams for the whole herd. The ADG was higher for the male (546.48 grams) than for the female (520.29 grams), and its was higher for the CT than the CC, but the difference was not statistically significant (P>0.05). The feed conversion ratio (FCR) was 2.69 kg. The estimated lean percentage at 8.5 months old was 64.08%. The results indicate that Piétrain stress negative pigs could develop well on the farm conditions in Hai Phong, Vietnam

Fatigue performance of tubular X-joints: Numerical investigation

The cyclic actions due to waves, currents and winds on offshore platforms frequently cause fatigue cracks at hot-spot locations. The remaining fatigue life of such connections depends significantly on the fatigue driving force often measured by the stress-intensity factors. This study examines the fatigue performance of tubular joints fabricated using a new type of enhanced partial joint penetration weld details under constant-amplitude brace in-plane bending actions. The numerical study ascertains the crack propagation angle, the crack-front profile and the interaction between adjacent cracks on the stress-intensity factors