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In the 1980s of the twentieth century, universities in developed countries began to realize the growing gap between the capabilities of new graduate engineers and the actual requirements of engineering branches. The strong progress of technology requires engineers to have the intellectual abilities and necessary job-specific skills to master that progress. This paper focuses on Conceive, Design, Implement and Operate (CDIO) approach-based teaching for students majoring in electrical and electronic engineering technology at engineering universities in Vietnam to demonstrate the feasibility of the teaching model. The experimental method of synthesizing qualitative and quantitative results for 90 students in control and experimental classes was used. The experimental and control classes both had 45 students. SPSS software version 22 was used to gather data and evaluate the learning results of the two experimental and control groups. According to the findings of the T-test analysis of the independent variables for the two groups, the experimental class performed better in academics and had students in the experimental group who were more satisfied with their post-test scores. This result contributes to confirm that the use of the CDIO-based teaching model in Vietnam is effective for students majoring in electrical and electronic engineering technology.

Plasma creation technology in an aqueous environment is being evaluated for research and practical applications, particularly in the field of materials and nano processing, as well as environmental pollution treatment. Important factors that influence the appearance of plasma when performing electrolysis by high-voltage DC (direct current) in aqueous environments are voltage, distance between electrodes, pH, conductivity and ambient temperature, as well as the nature of the electrode, which has been suggested by concurrent works to be the controlling factor of the other ones. Specifically, it is indicated that the plasma typically appears at a high voltage of about 15 kV and a distance between electrodes of 200 mm, with the earliest appearance occurring with the tungsten (W) electrode. Additionally, pH, conductivity and temperature variations for effective plasma creation have been found in all investigated electrodes. Finally, it has been found that the water-soluble plasma on the W electrode produces more gas than those in iron (Fe) and copper (Cu) electrodes. After the reactions, the lowest dissolution belonging to W electrode could be attributed to the inertness of W in comparison with Fe and Cu, resulting in a minimal value of the zeta potential. In addition, the size of Cu and Fe nanoparticles achieved in the investigated solution was approximately 200 nm, whereas W nanoparticles were two separate sizes of 100 and 500 nm. Therefore, this work could offer the needed agency for technological applications in industrial wastewater treatment and high-purity nanoparticle fabrication.

Previous studies on service recovery performance have merely focused on identifying the factors which affect it from the service provider side. This study investigates the effect of customer participation on Vietnam retailing service recovery performance. A structural model was developed and tested using data surveyed from 231 respondents who were currently full-time employees in Vietnam retailers. The results show that the more customer participation which frontline employees perceive, the more effective the service recovery they perform. Moreover, the results indicate that the more effective service recovery which frontline employees perform, the less stress they confront. Empowerment of and training for employees have an equivalent impact on the service recovery performance of frontline employees. However, there is no significant relationship between service recovery performance and intention to leave frontline employees.

Vietnam's Mekong Delta region contains a sizable amount of acid-sulfate soil, which has properties that harm plants, such as low pH, aluminum and iron toxicity, hydrogen sulfide and sulfate acid. The study aims to gather helpful information about the problems with acid sulfate soils' chemical makeup so that suggestions can be made for improving these soils in the Mekong Delta. These methods mainly review studies and projects on the properties, constraints and management improvement of acid-sulfate soils and recommend the proper methods for sustainable use. The Mekong Delta contains many sulfidic or acid-sulfate-producing materials. Soils that contain acid sulfate are especially vulnerable to the consequences of climate change. Therefore, evaluating and predicting how acidic soil impacts soil quality and the affected factors such as drought, water scarcity, rainstorms, floods and saltwater intrusion are essential. Selecting cultivars that can withstand acid sulfate or salt is easy and inexpensive. Designing appropriate farming models is necessary in the interim. To correctly manage and exploit acid sulfate soils in the current situation, one must also be aware of their distribution, physicochemical makeup and biological properties. [ABSTRACT FROM AUTHOR]

Feeding with 10% leucosaccharides for 3 weeks mitigated the development of adenine-induced chronic kidney disease in mice, as assessed by plasma urea, renal expression of inflammatory- and fibrosis-associated molecules, and colonic expression of tight junction proteins. Leucosaccharides are exopolysaccharides produced by Leuconostoc mesenteroides subsp. mesenteroides strain NTM048. Sequencing of 16S rRNA also revealed that leucosaccharides reverse the accumulation of Desulfovibrionaceae and Bifidobacterium and the loss of Akkermansia following exposure to adenine. Taken together, the data suggest that supplementation with leucosaccharides may effectively prevent or improve management of chronic kidney disease by restoring the microbiota and the integrity of colonic barriers.

This study shows that the pre-exponential frequency in the general-orders of kinetics (GOK) model depends on the ratio between the initial number of trapped electrons (n0) and the total concentration of trapping states (N) as well as the frequency factor. The frequency factor can be calculated by the one trap-one recombination (OTOR) model and does not depend on the ratio of n0/N. That means the ratio of n0/N can be deduced based on a comparison of the GOK and OTOR models. When the ratio of n0/N is approximately 1, the sample is in the dose-saturation level. Therefore, at the first time, this study has been determined the dose-saturation level of the sample from the thermoluminescence (TL) curve fitting.

In the present study, an anti-inflammatory effect of enzymatic whey protein hydrolysate was examined in human intestinal Caco-2 cells. Stimulation of Caco-2 cells with tumour necrosis factor (TNF)-α induced interleukin (IL)-8 expression through the activation of nuclear factor kappa B p65, spleen tyrosine kinase and mitogen-activated protein kinases pathways. Pre-treatment of cells with whey protein hydrolysate reduced TNF-α-induced IL-8 expression. Mass spectrometry analysis has identified the active tetrapeptide IPAV, which corresponded to amino acids 94–97 of β-lactoglobulin. Pre-treatment of cells with IPAV reduced TNF-α-induced IL-8 expression and the increase in phosphorylation levels of key cellular signalling proteins. Pharmacological inhibition of peptide transporter 1 (PepT1), but not of calcium-sensing receptor, attenuated IPAV-mediated suppression of IL-8 expression. In summary, a novel anti-inflammatory tetrapeptide IPAV, derived from whey protein hydrolysate, reduced IL-8 expression induced by TNF-α. Our results suggest that IPAV, transported by PepT1, can suppress inflammatory signalling in intestinal cells.

A study of drying parameters on the drying process of Pisum Sativum bean was carried out. The effects of drying temperature of moisture air from 40°C to 80°C on the drying time and on the drying kinetics were demonstrated not only on conventional electric dryers but also on heat pump dryers. Besides, checking the steady operation of the heat pump dryer was also considered. The results show that, when temperature rises, the shorter time and the faster removal of moisture content can be obtained for both dryer systems. Drying in an electric heater at 80°C took only 1 hour 45 minutes, but the broken skin of pea seeds happened. The comparison of heat pump dryer and electric dryer was presented with the shorter drying time on heat pump than electric dryer as a result of removing water vapor from moisture air at the evaporator of heat pump, it led to the reduction of specific humidity of air entering the drying chamber. And the last impressive result which can be seen is that the drying rate of a heat pump is higher than an electric dryer at the same drying temperatures beside the energy consumption of electric dryer is 2.76 times as much as that of heat pump dryer.

According to statistics from the Ho Chi Minh Energy Saving Center, the electricity costs of the air conditioning system for office buildings are about 70% of the electricity costs. There are many solutions that have been proposed to reduce the operating costs of the air conditioning systems, this article discusses a method of accumulating cold to reduce the cost of electricity for the air conditioning system of an office building.

The analysis of extracting potable water from the humid ambient air has been done by using the model of vapor-compression refrigeration (VCR) system for the case study in Vietnam. The temperature and relative humidity of moist air in Danang province in Vietnam were recorded for a whole year. The typical day in each month of year with detailed values of temperature and relative humidity for 24 hours were presented and used to identify the production of water from the air. The results show that, the temperature at the outlet of air stream throughout evaporator of VCR system is about 13°C in which the energy consumption to produce 1 liter of water is lowest. Besides, the electricity consumption cost in Vietnam varies in a day with various tariffs: at the peak load, medium load and low load, depends on the time of the day. The production price for one liter of water is also considered and working plans are proposed for the system by the time of the day.

This study analyses the performance of heat transfer process which occurs in the convective boiling of Hydro fluoro Olefin (HFO) refrigerant, R1234yf, in horizontal tube. Heat transfer and pressure drop of R1234yf are analyzed and computed at the same working conditions on the same size of outer diameter of tube do = 9.52 mm with difference of inner surface, one is a smooth surface and microfin for other. The flow pattern maps were built at 5°C saturation temperature with 8.62 kW/m2 of heat flux, it is presented that flow pattern of helix flow occurs at very low mass flux and low quality, while at that condition on smooth tube the flow is still stratified wavy flow. The comparison of heat transfer performance between microfin and smooth tube would be evaluated on enhancement factor E, penalty factor P and efficiency index I. With the mass flux on the range G = 111 -- 333 kg/m2s for 5°C boiling temperature, the results show that, average value of E is 2.18; 1.45 of P and 1.54 of I. One more impressing thing is that, at the quality “x” larger than 0.8, the dryout phenomenon takes place on smooth tubes while microfin tubes do not have this phenomenon.

Radio direction finding system is a system that determines the direction or coordinates of radio signal sources. The main function of this system is to determine the direction of arrival (DOA) of an incident radio wave. DOA information plays an important role in array signal processing and has many applications in communications, radar, seismic survey, etc. In this study, we propose a method to estimate the DOA by using the simulated signal dataset obtained at the linear antenna array (ULA) and the suitable Long Short-Term Memory (LSTM) network model. The performance of the method is evaluated based on the root mean square error (RMSE) parameter and then is compared with 2 other algorithms, multiple signal classification (MUSIC) and deep neural network (DNN) in different cases such as deviation of incoming signals, variation of signal-to-noise ratio (SNR), and coherent incoming signals. The obtained results have shown that the proposed method has significantly improved accuracy compared to other methods. [ABSTRACT FROM AUTHOR]

Safety evaluation of traffic conflict is a very important and challenging issue in evaluating intersection safety under incomplete traffic accident data conditions and is also one of the main safety surrogate measures of analyzing accident data recently. It helps to analyze and solve intersection problems comprehensively and deeply. From there, it helps to improve traffic safety as well as reduce the risk of traffic accidents at intersections. Various evaluation methods based on traffic conflict have been proposed to make conflict safety levels at intersections more consistent and objective. However, a major concern is that many existing measurements are still subjective and are not easy to obtain uniformly. This study aimed to develop a model for safety evaluation at intersections in a comprehensive way that may be expected to directly link to the severity of the accident from different evaluation indicators. First, the three factors, including time to collision (TTC), conflicting speed (CS), and deceleration rate (DR) to avoid a crash, are introduced into safety evaluation of conflicts as the indicators. And then, as regards the fuzziness and randomness of the evaluation indicators, the qualitative concept has to be converted into a quantitative one utilizing cloud model, which implements the natural transformation between the qualitative concept of the safety level of traffic conflict and the membership degree of the evaluation indicators corresponding to the different safety levels. Finally, an indicator weight model is built based on the information entropy and the AHP method to determine the safety level. We illustrate the practical implementation of the proposed method using actual data of a typical signalized intersection from Hanoi City of Vietnam. The results indicate that traffic conflict analyzed by the proposed method was appropriate with actual state of the intersection, and the proposed method is simple, effective, and feasible, so it has a certain application value. [ABSTRACT FROM AUTHOR]

Aim: This study measured the level of knowledge, attitudes and practices towards COVID-19 prevention and examined associated factors among patients at a national tertiary general hospital in Vietnam. Methods: Adult patients admitted to University Medical Center during research period were recruited in a cross-sectional study, which employed a convenience sampling method with a 4-component questionnaire in order to examine the patients' consciousness towards COVID-19 spreading prevention based on four aspects: demographic characteristics (10 items), knowledge (14 items), attitudes (6 items), and practices (7 items). Results: The study involved 2769 respondents (18– 90 years) with the mean age of 38.05± 13.91 years. About two thirds of the respondents obtained diploma degree or higher (63.4%) and shared their living space with others (64.4%). The majority of patients settled in urban area (74.9%). All participants stayed informed about COVID-19, with the most commonly used channels like television (75.2%), the Internet (72.2%) and phone (69.8%). The vast majority showed sufficient knowledge (93.7%) and positive attitudes (76.3%). Just over half of participants remained good practiced of COVID-19 prevention (57.7%). On average, the factors of younger age, higher educational level, frequency and department of admission, and the number of COVID-19 informative channels were significantly associated with sufficient knowledge, positive attitudes, and good practices regarding preventive action against COVID-19 spreading. The optimistic attitude and having more undergoing chronic diseases were associated with the likelihood of well-practiced COVID-19 preventive measures (OR 3.63, 95% CI 1.54– 8.55, p=0.003 and OR 0.86, 95% CI 0.78– 0.98, p=0.02, respectively). Conclusion: The results of this study demonstrated that the likelihood of good preventive practices in the fight against COVID-19 pandemic was influenced by attitudes and several sociodemographic factors. More drastic interventions for the prevention of COVID-19 should be widely furnished and equipped in hospitals, through various routes to maximize the efficiency and adherence to prevention practices. [ABSTRACT FROM AUTHOR]

NK cells are phenotypically and functionally diverse lymphocytes due to variegated expression of a large array of receptors. NK-cell activity is tightly regulated through integration of receptor-derived inhibitory and activating signals. Thus, the receptor profile of each NK cell ultimately determines its ability to sense aberrant cells and subsequently mediate anti-viral or anti-tumor responses. However, an in-depth understanding of how different receptor repertoires enable distinct immune functions of NK cells is lacking. Therefore, we investigated the phenotypic diversity of primary human NK cells by performing extensive phenotypic characterization of 338 surface molecules using flow cytometry (n = 18). Our results showed that NK cells express at least 146 receptors on their surface. Of those, 136 (>90%) exhibited considerable inter-donor variability. Moreover, comparative analysis of CD56bright and CD56dim NK cells identified 70 molecules with differential expression between the two major NK-cell subsets and allowed discrimination of these subsets via unsupervised hierarchical clustering. These receptors were associated with a broad range of NK-cell functions and multiple molecules were not previously associated with predominant expression on either subset (e.g. CD82 and CD147). Altogether, our study contributes to an improved understanding of the phenotypic diversity of NK cells and its potential functional implications on a cellular and population level. While the identified distinct signatures in the receptor repertoires provide a molecular basis for the differential immune functions exerted by CD56bright and CD56dim NK cells, the observed inter-individual differences in the receptor repertoire of NK cells may contribute to a diverging ability to control certain diseases. [ABSTRACT FROM AUTHOR]

Cellulose nanocrystals (CNC) have been used as reinforcement in polymer nanocomposites to improve their mechanical and thermal properties. In this study, we synthesized CNC-reinforced polyurethane foams (CNC-PUF), which are the most important component of liquefied natural gas and liquefied petroleum gas insulation systems, using various CNC loadings. The temperature-dependent mechanical and thermal characteristics of the CNC-PUF samples were investigated. In addition, the microstructural and X-ray diffraction investigations of the composite samples were performed. It was observed that the thermal and mechanical characteristics of the CNC-PUF sample with 0.6 wt% cellulose nanocrystals were superior to those of neat PUF under room and cryogenic temperatures. These properties showed a significant dependence on CNC loading, temperature, and foam density. [ABSTRACT FROM AUTHOR]

This letter presents a new method to realize microwave low phase noise oscillators using high selectivity SIW filters. A perturbing via-hole is located inside the dual-mode circular cavity to significantly enhance the filter selectivity. By properly adjusting this perturbing via-hole position, the oscillator phase noise can be minimized at frequency location of the improved group delay peak. Several planar X-band oscillator prototypes have been fabricated and measured. Good agreement between experiment and predicted results is shown. The designed oscillators have advantages of simple design process, planar structure, and improved phase noise. At the oscillation frequency of 10.178 GHz, the measured real phase noise is −135.4 dBc/Hz@1MHz and −1.35 dBm output power. [ABSTRACT FROM PUBLISHER]

A modified method has been developed for the α determination in the 1/ E1+α epithermal neutron spectrum of reactor. It is based on the Cd-covered and without Cd-covered irradiations of two monitors. This method was applied to determine the α value in the channels of Dalat reactor and the results were compared with those obtained by the other methods. It appeared that the results of the modified method were in quite good agreement with those of other methods. It also showed that the modified method was simple in practical uses and a good application in the experiment of α determination in the reactor irradiation channels. [ABSTRACT FROM AUTHOR]

By using MCNP code and ethanol-chlorobenzene (ECB) dosimeters the simulations and measurements of absorbed dose distribution in a tote-box of the Cobalt-60 irradiator, SVST-Co60/B at VINAGAMMA have been done. Based on the results Dose Uniformity Ratios (DUR), positions and values of minimum and maximum dose extremes in a tote-box, and efficiency of the irradiator for the different dummy densities have been gained. There is a good agreement between simulation and experimental results in comparison and they have valuable meanings for operation of the irradiator., (Copyright 2010 Elsevier Ltd. All rights reserved.)