Dehydration of glucose into 5-hydroxymethylfurfural (HMF) was one of the most reactions in biomass conversion into high-value chemicals. This work aims to synthesize a catalyst for the efficient production of HMF from glucose. P-UiO-66 has been prepared and characterized using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Fourier-transform Infrared Spectroscopy (FT-IR). The synthesized catalyst showed excellent performance for the conversion of glucose into HMF. 99% HMF was achieved under optimal conditions (180oC, 8 h, 0.05 g catalyst). In addition, the P-UiO-66 was stable and highly active during the reaction condition, which can be reused four times without a significant decrease in HMF yield.

In the field of minimally-invasive surgery (MIS) research, a double roller pump is one of the medical therapy devices that have been used as an effective method for automatic pressure control via controlling the flow of rinsing fluid. For example, in knee arthroscopy, the inflated pressure inside the joint of the knee needs to be controlled adaptively with the blood pressure of the patient during the whole operation time. The stability of the pressure control takes an important role in avoiding risky situations like hemorrhages and fluid depletion. This paper is to present an application of the double roller pump which is used for controlling the pressure in the knee arthroscopy process. The pressure inside the knee joint was influenced by the actual flow of the rinsing fluid. The operation of the process was simulated and linearized for controller design. PID (Proportional Integrated Derivative) controller was designed with an anti-windup strategy for reducing overshoot. Some parameters of the controller were adjusted with different sets of pole placement for the output responses comparison. Among these sets of poles simulated, a better result was found for the effectiveness of the double roller pump usage in pressure control of MIS.

This paper introduces an experimental controlled model of a low-cost magnetic levitation system for education and research. The hardware model has been built for implementing the theory of control algorithms into real-time. This is to solve the circumstance of inadequate physical devices for testing principles and control theories. According to that, an LQR controller (Linear Quadratic Regulator) and the Kalman filter have been designed to control an iron ball stably at different positions. The Kalman filter is used to estimate state variables supporting the LQR controller for controlling the object to the desired positions. The results have been approached with the effective data transference of a low-cost hardware device that can control the object at different equilibrium points; the maximum steady-state error is around 4%. In addition, by adding noise to the system with the object’s mass changed, the position of the object is still controlled stably. The noise from the data of the sensors also influenced the quality of the designed controller LQG (Linear Quadratic Gaussian).

There are some approaches to researching riverbed evolution and bank erosion, such as morphology or dynamics. The aim of the paper is to present a numerical model that combines the calculation of riverbed evolution and riverbank erosion. The novelty of this study is that the flow is calculated by the 3D hydrodynamic model, so the frictional stress on the riverbank surface is calculated directly. The process of bed and bank erosion by flow was calculated using the 3D hydrodynamic model in combine with a sediment transport module. The slide of the riverbank was evaluated by a circular arc stability analysis. The pore pressure used in stability analysis was calculated by solving the infiltration flow equation. The model was tested by calculating the evolution of the Dong Nai river at Rua island. The calculations showed that the model requires one hour on a PC with an i7 core for computing 3 hours of reality. With such a calculation speed, the applicability of the model is quite good.

The measured discharge data at gauging stations are used in many areas such as transportation, irrigation and agriculture. Vam Nao River joines between Tien river and Hau river. This river has complex flow structures. Thus, the calculation of water flow in this river needs an authentic and accurate method. The main objectives of this paper were to evaluate the methods for calculating discharge in the Vam Nao gauging station. An adequate method was proposed to calculate the discharge on flood season at the Vam Nao station. In particular, the results of this paper use the result of two-dimensional hydrodynamic model which is simulated on the Telemac 2D software for the area from the Chau Doc gauging station and the Tan Chau gauging station down to the Long Xuyen gauging station and the Cho Moi gauging station. Based on the measured data and the results of this model, the measured discharge data at the Vam Nao gauging station in 2017 was tested and evaluated. The results showed that the measured discharge data in flood season at Vam Nao station needs to be improved and the technique of measuring discharge data in dry season should be applied in flood season

In this study, a horizontal underground flow constructed wetland with creeping burhead (Echinodorus cordifolius L.) was used to survey the treatment efficiency of domestic wastewater according to the hydraulic retention times. The results showed that at the retention time of 7 days, in the treated wastewater, the parameters of pH, SS, BOD5, N-NH4+, N-NO3, and P-PO43- reached grade A, while total Coliforms reached grade B of the national technical standard of QCVN 14:2008/BTNMT. This system can be applied in regions with suitable areas and low land prices for environmentally friendly treatment, at the same time, the re-use of remained nutrients as organic fertilizer sources and create a nice landscape for the local area.

In this study, an algorithm was proposed to classify the images based on the extracted one-dimensional probability density function. First, based on the resolution of grey level, each image was extracted into a representative one-dimensional probability density function and truncated on [0;1]. Next, the prior probability of the classified image was determined based on the fuzzy clustering problem. Finally, a principle to classify images was proposed. The image was assigned to the known group if it has the maximum value of the prior probability and a similar level to that group. The proposed algorithm was illustrated step by step, and applied to specific image sets. The application obtained a good result because it had fewer errors than other methods. This study also shows potential in practical application for many fields related to image recognition.

Dose calibrator is an indispensable instrument in nuclear medicine. Therefore, quality control of dose calibrator is routine work, which decisively contributes to treatment and diagnostic affection. The International Atomic Energy Agency, and The American Association of Physicists in Medicine have released instructions for dose calibrator quality control. In this paper, these instructions were applied for quality control of the dose calibrator which is equipped in Medical Physics Laboratory at Nguyen Tat Thanh University. The procedures include accuracy and precision test, check of reproducibility, background response, and linearity response. The results implied that the device passed the IAEA standard for educational, research, and even clinical use. The method described in this paper could be applied to similar devices used in nuclear medicine clinics.

In this paper, the combinatorial optimization problem with the objective function being a multiplication of several classical functions is concerned. Firstly, an equivalent master problem is constructed and then the corresponding multicriteria optimization version which plays an important role in finding an optimal solution to the original problem is shown. Based on the solution existence property to the original problem which is also an extremely supporting and efficient solution of the multicriteria optimization problem, a generic algorithm for the problem is given. The case with the multiplication of exactly two functions is also discussed. Finally, a linear time algorithm for solving the multiplicative 1-median location problem on a tree is proposed.

This research shows experimental results on the aphids’ effectiveness control of some extracts derived from the herbs. The toxicity of tea seed (Camellia oleifera) (using the ethanol method), wormwood (Chenopodium ambrosioides L.) and water pepper (Polygonum hydropiper L.) (using the water method) towards the aphids with laboratory and greenhouse conditions, which have been evaluated, through the corresponding aphids killing effect of the tea seed extract at a concentration of 20% had the best effect (75.25% for aphids after 96 hours of spraying), wormwood oil had the best effect 76.67%  for aphids at high concentration of 0.2%, and water pepper essential oil had the best effect 64.25% for aphids at 0.25%. LC50 of wormwood essential oil, water pepper essential oil, and tea seed extract were 0.06%, 0.11%, and 5.24%, respectively. The mixture of extracts with 0.4% wormwood oil concentration and 20% tea seed achieved the best efficiency of 97.33% against aphids at 96 hours after spraying. The effect of killing aphids on passion fruit plants was tested in greenhouse conditions at a concentration of 250 ml/L. It was highly effective in controlling aphids.

This study aimed to investigate the extraction conditions of chlorophyll and antioxidants from pandan leaves (Pandanus amaryllifolius Roxb) and stabilize their bioactivities by encapsulation and foam-mat drying. The study had two experiments (i) effect of ethanol concentration (40-100%), extraction temperature (70-90℃) and time (10-30 minutes), and material to solvent ratio (1:5-1:25, w/v) on the content of chlorophyll and antioxidants; and (ii) effect of albumin (5-15%) and carboxymethyl cellulose (CMC) (0,5-1,5%) on the stabilization of antioxidant activity. The result showed that the extraction with the ethanol of 80%, temperature of 80℃ in 20 minutes with the material to solvent ratio of 1:20 (w/v) was suitable for extracting chlorophyll and antioxidants. Albumin of 10%, CMC of 0.5%, and foam-mat drying temperature of 60-65oC were selected for stabilizing bioactive compounds in foam powder.

This study is to evaluate the change of area in agricultural land uses in My Xuyen district, Soc Trang province through the satellite image data provided by Japan Aerospace Exploration Agency. The results showed a difference in the percentage of land use types changed in two areas of the district. For the freshwater region in the North of the district, there was little change of area in the rice crops and cash crops. These land use types were mainly converted for construction areas and other plantation trees. Meanwhile, there was high transformation in the saltwater and brackishwater ecology region, the area of rice-shrimp farming was reduced due to changing to the improved extensive and semi-intensive farming models. By the farmer interview method, these results showed that saline water intrusion, rainfall, costs of input materials, labor costs, consumption of materials in the production process, agricultural product prices, markets, lack of labors, and Covid-19 epidemic were important influences on production efficiency and farmers' decision to change land use.

This study aims to assess the vaccination coverage and post-vaccination immune status of poultry  against type A/H5 (H5 highly pathogenic avian influenza, H5 HPAI) in Dong Thap province during the period of 2019–2020. Datasets for vaccination status of poultry used in this study were retrospectively obtained from Dong Thap Sub-Department of Animal Health. Our results indicate that vaccination coverage of H5N1 vaccine among districts/cities in Dong Thap province was inequivalent. Six of 12 districts/cities had vaccination coverage below 70%. In addition, the vaccination coverage with H5N1 vaccine for duck was higher than that of chicken. Besides, the percentage of poultry population achieving vaccination protection in 2020 (84.62%) was higher than in 2019 (59.46%). The protection rate of post-vaccination by species increased from 2019 to 2020, and the protection rate in duck (77.78% in 2019 and 89.05% in 2020) was higher than that of chicken (50.0% in 2019 and 60.61% in 2020). Our study provides important information for assessing the vaccination status and post-vaccination immune response against highly pathogenic avian influenza type A/H5 in Dong Thap province.

This research used three machine learning algorithms-MLC (neural networks-NNET, random forest-RF, and support vector machine-SVM) for classification of Sentinel 2 imagery into forest categories in Bu Dang district, Binh Phuoc province. Ten types of land use and land cover were discriminated for the whole area, in which 6 forest classes were classified in the study area. The highest accuracy was found using RF with overall accuracy of 90% and Kappa of 0,86, followed by the NNET and SVM algorithm. Among the Sentinel-2 spectral bands, the SWIR B11, followed by the red-edge B5, B6, narrow NIR B8A, SWIR B12, and the green B3 contributed the most to the accuracy of the forest types of classification. In conclusion, the results of this study demonstrated that the random forest algorithm is well-suited for vegetation mapping using Sentinel imagery, which can be applied to large-scale forest type’s classifications.

The study was carried out to determine the suitable nutrient formula for the growth and yield of watermelon (Citrullus lanatus) grown by hydroponic root dipping technique. The experiment was arranged in a randomized complete block design in 4 treatments with 4 replicates for each treatment. The four treatments were  FV1, FV2, DHCT, and control. The results showed similarity in the number of leaves, leaf size, stem diameter, and root length. However, there were significant differences in yield components and fruit yield cultivated in different nutrient solution formulations. In which, treatment FV1 and DHCT showed fruit height, fruit perimeter, and fruit weight (1.47 and 1.53 kg/fruit, respectively), and yield (4.49 and 4.66 tons/1,000 m2, respectively)were as high as that of the control. Particularly, FV1 treatment showed the lowest accumulation of nitrate in watermelon. However, the concentration of nitrate accumulated in watermelon in the experiment was much lower than the maximum allowed level as prescribed.

The study focused on the effects of increased application of organic fertilizers and decreased application of chemical fertilizers on cucumber (Cucumis sativus L). One-factor field experiment was conducted using a randomized complete block design with 8 triplicated treatments including (1) control: without fertilizers; (2) VC100: chemical fertilizer application (120 kg N + 80 kg P2O5 + 140 kg K2O); (3)-TQ100 – application of 8 tons/ha of vermicompost; (4) DT100: application of 200 L/ha of soybean fertilizer; (5) VC50TQ50: combining 50% of chemical fertilizers with 50% of vermicompost; (6) VC50TQ75: combining 50% of chemical fertilizers with75% of vermicompost; (7) VC50ĐT50: combining 50% of chemical fertilizers with 50% of soybean fertilizer; and (8)-VC50ĐT75: combining 50% of chemical fertilizers with 75% of soybean fertilize. The results showed that plants treated with vermicompost or soybean fertilizer or by combining organic fertilizers with chemical fertilizers were similar in size as compared to treatment with chemical fertilizer application. Physiological indicators (LAI, SPAD) increased under the combined application of chemical fertilizers with vermicompost. Combining 50% of chemical fertilizers with 75% of vermicompost gave the highest yield components (fruit number, fruit weight, and fruit weight per plant), highest fruit yield (24.98 tons/ha), and economic efficiency (profit of 76.59 million VND/ ha and profit margin of 0.62). Fruit quality indicators were not significantly differed, Brix value tended to increase and nitrate content tended to decrease under organic fertilizer addition. 

This study aimed to reuse the nutrients of biogas effluents to create liquid and solid organic fertilizers, contributing to reducing biogas effluents directly discharged into environments and supplementing nutrients for crops. Biogas effluent’s physico-chemical compositions were evaluated for quality. Fish emulsion and beneficial bacteria were added to the effluent to produce liquid organic fertilizer. For the solid fertilizer, liquid biogas effluents were absorbed into coal slag and then mixed with a sugarcane filter. The results showed that the best mixing ratio between biogas effluents and fish emulsion to create the standards of liquid organic fertilizers was 60:40 (v/v). For the solid form, a ratio of 30:70 (w/w) between sugarcane filter and coal slag in a combination with the addition of 16.7% fish meal and beneficial bacteria was the best formula. The storage temperature to ensure the composition and quality of these two types of organic fertilizers is 30oC.

Evaluation of the status of some main inshore fisheries in the western seas of Ca Mau province was conducted from August 2021 to April 2022. Results showed that gill nets, trawl nets, squid fishing, and octopus trapping with snail shells were being developed in the inshore of Ca Mau province. These fisheries can be exploited all year round. Fishing yields of the gill nets (17.9 tons/year), squid fishing (11.3 tons/year), and octopus trapping (29.3 tons/year) were high, except for trawl nets with the lowest catch (8.44 tons/year). The trawl nets had the highest ratio of trash fish at 16.4%. The profit of gill net fisheries (1,174 million VND/year) was the highest, and squid fishing and octopus trapping had a low rate of return ( 0.2 times and 0.37 times, respectively). Gill nets, squid fishing, and octopus trapping were passive gears, low trash-fish ratio, and low impact on fisheries resources, those fisheries should be encouraged to develop. However, squid fishing and octopus trapping had low-profit margins, it is necessary to research and support these two fisheries to develop to create jobs and increase income for fishermen in coastal areas. 

The study was conducted to investigate the effects of heating modes on the gel quality of surimi produced from striped catfish (Pangasianodon hyphophthalmus) shredded meat. The study included three experiments (i) the effects of direct heating time at 90℃, (ii) the effects of heating time at 40℃ in stage 1 (two-step heating mode), and (iii) the effects of heating time at 90℃ in stage 2 (two-step heating mode) on gel surimi quality. The results showed that the gel strength, hardness, springiness, cohesiveness chewiness, and water holding capacity of gel surimi of striped catfish shredded meat were 338 g.cm; 2,039 g; 0.870; 0.316; 558 g, and 84.8%, respectively if applying direct heating at 90℃ for 20 minutes; while gel strength, hardness, springiness, cohesiveness, chewiness, and water holding capacity of the gel surimi were 377 g.cm; 2,488 g; 0.98; 0.333; 819 g; 88.9%, respectively if using two-step heating at 40℃ for 30 minutes (step 1) and then increased to 90℃ for 20 minutes (step 2). In brief, the gel quality of two-step heating surimi had better than that of direct heating surimi.

The objective of the study was to evaluate the species composition of Cladocera and Copepoda in intensive brackish water shrimp ponds. The study was conducted in 6 shrimp ponds including 3 black tiger shrimp ponds and 3 whiteleg shrimp ponds at Vinh Trach Dong commune, Bac Lieu city, Bac Lieu province. The results showed that the water environmental parameters in shrimp ponds, such as temperature, pH, salinity, TAN, NO3-, PO43-, TN, TP, and chlorophyll-a were in the suitable range for shrimp. A total of 34 zooplankton species were recorded in shrimp ponds, of which cladocera (1 species) and Copepoda (4 species) accounted for a very low proportion. The abundance of Copepoda (including nauplius larvae) ranged from 19,112 to 169.778 ind.m-³ and Cladocera from 0 to 2,650 ind.m-3. Zooplankton species recorded were Acartia clausi, Apocylops sp., Microsetella norvegica, Schmackeria dubia (Copepoda), and Moina sp. (Cladocera). Schmackeria dubia and nauplius larvae were predominant in both black tiger and whiteleg shrimp ponds. Shrimp productivity was positively correlated (p>0.05) with the Copepoda density. The development of Copepoda contributed to an increase in shrimp production.

Taste metaphors play an important role in human cognitive functioning, and many abstract concepts are constructed through taste metaphors. From the perspective of cognitive linguistics, the article is to systematically study the metaphor of the taste word 苦 (suffering) - bitter in Chinese and Vietnamese. Research results show that the taste metaphor 苦 (suffering) - bitter in two languages mainly focuses on five areas: visual/tactile, emotional, physical world, social life, and level. Further comparative analysis showed that the metaphor of taste word (suffering)-bitter in Chinese and Vietnamese has similarities, which can be attributed to the similarity in human cognitive patterns, but there are also differences that can be attributed to cultural differences.

Prompted by a perceived gap in the literature, this article provides analyses of the move structure and lexical bundles in a corpus of 40 Vietnamese-medium research article introductions in two sub-fields of applied linguistics (viz. English Language Teaching and Pragmatics & Discourse Analysis). The selected research artiles were published between 2011 and 2015 in high-quality linguistics journal domestically. The move structure analytical framework was developed based on Swales’ Create A Research Space (CARS) models (1990, 2004) and with reference to the self-compiled corpus of the current study. With respect to the other theoretical construct, Biber et al.’s (1999) notion of lexical bundles was adopted.  The analyses revealed a variety of move structures, and a total of 53 lexical bundles that possibly function as linguistic realizations of the moves in the corpus.

The Mekong River Delta has long been considered an invaluable asset and a featured beauty for the Southern region of Viet Nam. The river landscape has become the material for writing by many writers including Nguyen Ngoc Tu. In the pages of Nguyen Ngoc Tu, the Mekong River Delta waterway appears very lively and impressive, both close and familiar when present in each of the food and accommodation of indigenous people, both poetic and attractive to tourists. In particular, those rivers also show a naked reality with grim life scenes and an alarming reality of an environment that is being destroyed. Nguyen Ngoc Tu's composition has raised a critical voice, calling for raising awareness and practical actions to preserve the values ​​of nature in general and the river in particular.

The objective of this study is to measure the effect of the COVID-19 pandemic on the market efficiency of Ho Chi Minh Stock Exchange (HOSE). The data used in this study is the daily VN30-Index for the period from August 11th, 2017 to May 26th, 2022. Based on the collected data, the rolling window was applied to calculate the Hurst exponent. The results showed that the Hurst exponent value of both periods was larger than the efficiency Hurst exponent value (H = 0.5). In addition, the exponential value at the post-stage is larger than the Hurst exponent value pre-stage of the pandemic outbreak. Therefore, it can be concluded that the outbreak of the COVID-19 pandemic exacerbated market inefficiencies. Moreover, HOSE had a time-varying market inefficiency because Hurst's value increased as the rolling window length increased. In conclusion, the Vietnamese stock market in both the periods of before and after the outbreak of the pandemic did not have a weak form of market efficiency. Thus, investors could predict the price of the stock based on the information collected in the past and look for opportunities.