Journal of Science and Technology - IUH

OPTIMIZATION OF PHOSPHORUS LEACHING FROM SEWAGE SLUDGE OF BINH HUNG DOMESTIC WASTEWATER TREATMENT PLANT

2024-04-09T07:23:31+00:00

Leaching phosphorus (P) in dewatered sludge from domestic wastewater treatment plant is an important step to convert solid P compounds into a soluble form that can be separated and recovered as clean products. In addition, optimization of leaching conditions is essential to minimize the amount of chemicals used and water resources in developing P recovery processes. This study combines experimental studies and simulation calculations by using the Aqion-PRO hydrochemistry tool to determine the optimal conditions for P leaching. Type of leaching agent, liquid-solid phase ratio, agent concentration and leaching time are researched to optimize. The liquid-solid phase ratio and leaching agent concentration are correlated to the P leaching ability from the sludge. The H₂SO₄ 1.1M, phase ratio 5 and leaching time 60 minutes were determined as the most optimal parameters to leaching phosphorus, P leaching efficiency can reach about 85 ± 3%.

OPTIMIZING CONDITIONS TO YIELD TOTAL PHENOLIC CONTENTS USING ULTRASOUND-ASSISTED EXTRACTION FROM CASHEW TESTA (ANACARDIM OCCIDENTALE LINN.)

2024-09-10T01:19:10+00:00

The optimal experiments on cashew testa (Anacardim occidentale Linn.) were conducted with three factors of extraction (including liquid-solid ratio, extraction time, and extraction temperature), and the responses is total phenolic content (TPC). The result showed the highest of TPC at 375.73 mg of gallic acid equivalent/g dry weight (mg GAE/g DW) when the solvent is methanol, liquid-solid ratio at 42.6 (mL/g), extraction time at 97.8 (min), and extraction temperature at 48.5^oC. The quantitative analysis of five main components of cashew testa including Catechin, Epicatechin, Epigallocatechin gallate (EGCG), Epicatechin gallate in the seven locals in Vietnam was performed by HPLC. The results showed that Epicatechin (25.495-44.539 mg/g DW) was the highest content, following by Epicatechin gallate (7.492-13.501 mg/g DW), Catechin (2.625-4.279 mg/g DW), EGCG (1.609-2.168 mg/g DW), and caffein (1.335-1.168 mg/g DW).

ASSESSMENT OF THE EFFECTIVENESS OF CHICKEN MANURE BIOCHAR ON HEAVY METALS ADSORPTION IN SALINE SOIL IN CAN GIUOC, LONG AN

2024-06-10T11:26:08+00:00

In the present study, a leaching column model was performed to evaluate the effects of adding chicken manure biochar (BC) (350, 450 and 600^oC with retention time of 1, 1.5 and 2 hours) on heavy metal adsorption capacity in saline soil in Can Giuoc district, Long An province. The collected soil sample was determined to be strongly acidic (pH 3.9), while BC was strongly alkaline (pH 7.2 – 9.6). The high electrical conductivity (EC) content (4.39 ± 0.289 dS/m) shows that the soil in the study area is saline, EC is higher than chicken manure BC (<1.5 dS/m). In particular, the content of Cd (4.63 ± 1.47 mg/kg), Pb (203.33 ± 18.56 mg/kg) and Zn (333.33 ± 1 221.06 mg/kg) in soil exceeded the value QCVN 03:2023/BTNMT. After adding BC through the leaching column model, the content of heavy metals in the soil decreased to less than 0.01 mg/kg. The research results are a database that helps policymakers monitor progress in saline soil reclamation and soil health management.

DETERMINE THE INTENSITY OF BORED CONCRETE THROUGH ULTRA SOUND PULSE TRANSMISSION SPEED

2024-05-08T03:54:39+00:00

The importance and practical contributions of bored piles in the field of construction are extremely large and bold. Most of the high - rise buildings on the territory of Vietnam are firmly built on the bearing foundation system as bored piles, meeting high requirements on bearing structure as well as increasingly advanced concrete construction technology. Nowadays, the quality of bored piles is controlled based on TCVN9396: 2012 [2]. However, this standard still has many shortcomings, causing significant difficulties in checking and accepting bored piles after construction. The research has provided practical solutions to remove obstacles that the standards are facing, namely: through ultrasonic transmission speed to determine the concrete intensity of bored piles. This is the limitation in the standard TCVN 9396: 2012 [2] is currently applying.

RESEARCH USING THE QUANTITATIVE EVALUATION METHOD BASED ON PRODUCT QUALITY CRITERIA TO SELECT FABRIC THAT MEETS THE REQUIREMENTS OF UNIFORM SHIRTS FOR MAN LECTURERS AT HO CHI MINH CITY UNIVERSITY OF INDUSTRY

2024-06-12T12:40:58+00:00

This article presents the results of research using a quantitative assessment method based on product quality criteria to select fabrics that meet the requirements of uniform shirts for man lecturers at Ho Chi Minh City University of Industry. The study used the method "Weighted average" based on 11 fabric quality criteria (tensile strength on warp direction of fabric, elongation on warp direction of fabric, fabric moisture absorption, fabric water capillarity on warp and on welf direction, fabric air permeability, fabric drape coefficient, fabric crease resistance coefficient, fabric shrinkage due to washing, fabric drying time after washing, price of fabric) to calculate the overall quality level (OQL) of the product. The method was conducted by following steps: 1) determining product categories, 2) identifying quality characteristics, 3) formulating weights for quality characteristics, 4) measure quality criteria of the products, 5) determine the relative quality index qi, 6) calculate the overall quality level and apply to assess products. The results show that the overall quality levels of the three fabrics (100% cotton, PE-CP/65-35 and 100% polyester) receive values of 1.00, 1.23 and 1.20, respectively. From this result, white woven fabric made from 65% polyester and 35% cotton was selected as the most suitable fabric to make uniform shirts for male lecturers at Ho Chi Minh City University of Industry.

CULTURE BEHAVIOR OF STUDENTS OF INDUSTRIAL UNIVERSITY OF HO CHI MINH CITY IN THE PERIOD OF INTEGRAL

2024-10-01T07:00:34+00:00

In the current era of international integration, the good and the bad coexist, significantly affecting the development of people's character in general and students in particular. Educating students in cultural etiquette during this period of integration is of utmost importance. This article contributes to clarifying some concepts of cultural etiquette, the cultural etiquette rules of students at Ho Chi Minh City University of Technology, Vietnam. Through survey data, it evaluates the current situation of achievements and limitations in implementing the cultural etiquette of students at Ho Chi Minh City University of Technology, Vietnam. Based on this, it proposes some basic solutions to improve the cultural etiquette of students at Ho Chi Minh City University of Technology, Vietnam, in the current period of integration.

MANUFACTURING OF A TRANSFORMER FOR CONVERTING 3-PHASE TO 6-PHASE ELECTRIC POWER SOURCE

2024-06-19T06:27:02+00:00

Nowadays, due to its advantages such as better fault-tolerant performance, improved system reliability, better efficiency, lower power per phase, lower torque oscillation with better torque density, multiphase AC machine (with the phase-number is higher than 3) has been widely accepted and adopted for electric drive applications. However, multi-phase machine applications required to be powered from multiphase power source or drive system. Unfortunately, multi-phase power supply or drive system still has not been offered in commercial market. Thus, a 3 kVA transformer with a novel winding arrangement to have the ability to convert conventional 3-phase power supply input to 6-phase power source output for multiphase machine application has been investigated and manufactured at the Faculty of Electrical Engineering Technology, IUH, Vietnam. Testing on the transformer shows that it could supply a 6-phase output power with low high-order harmonics. Therefore, the multiphase transformer prototype is essential for testing multiphase machine application.

A NOVEL ROBUST HYBRID BS_NSTASOSM CONTROL STRUCTURE FOR VECTOR CONTROL FOC OF SPIM DRIVES

2024-05-30T02:43:27+00:00

In this paper, a novel robust hybrid control structure based on the combination between (NSTA_SOSM) second- order sliding control using super-twisting algorithm and the (BS) Backstepping for vector control of SPIM drive systems is proposed. This structure effectively solves the weaknesses of both traditional (BS) Backstepping control and (SM) sliding control, develops and enhances the performance of FOC control by combining second-order sliding control using super-twisting algorithm to increase convergence speed and the reference tracking ability more quickly and accurately, the new controller works robust and stably even when working in conditions of uncertain parameter systems and load disturbances, the chattering phenomenon is almost eliminated. The obtained results by simulation using the Matlab/Simulink tool verified the performances of new proposed control constructure.

DEVELOPMENT OF AUTONOMOUS SURFACE VEHICLES FOR REAL-TIME WATER QUALITY MONITORING IN SHRIMP PONDS

2024-04-05T08:02:34+00:00

Nghiên cứu này tập trung vào việc phát triển một phương tiện tự hành trên mặt nước (ASV) để cải thiện quá trình giám sát chất lượng nước trong nuôi tôm. ASV được thiết kế thông qua mô phỏng máy tính và công nghệ in 3D, nhằm tối ưu hóa hiệu suất và độ tin cậy. Với trang bị GPS và cảm biến siêu âm, ASV có khả năng tự định vị và tránh chướng ngại vật, giảm thiểu sự can thiệp của con người. Pin Lithium Polymer được sử dụng để kéo dài thời gian hoạt động của ASV. Hơn nữa, ASV kết nối với ESP32 và Raspberry Pi 4, hỗ trợ Wi-Fi và Internet, cho phép phát triển một máy chủ web hiển thị dữ liệu môi trường nước được thu thập một cách thời gian thực. Mục tiêu của nghiên cứu là đạt được việc thu thập dữ liệu liên tục và chính xác với khả năng điều hướng chính xác đến các điểm đã định với sai số dưới 3 mét. Các tiêu chí đánh giá bao gồm độ chính xác vị trí, thời gian hoạt động liên tục và độ chính xác của cảm biến. Kết quả dự kiến sẽ giúp giảm chi phí, cải thiện độ chính xác dữ liệu và nâng cao hiệu quả quản lý trong nuôi tôm. Điều này không chỉ mang lại lợi ích về mặt kinh tế mà còn góp phần vào việc bảo vệ môi trường sống của tôm, qua đó đảm bảo sự phát triển bền vững của ngành nuôi trồng thủy sản.

RESEARCH OPTIMAL FLAT GRINDING PARAMETERS TO IMPROVE SURFACE ROUGHNESS OF SKD61 STEEL

2024-11-18T00:54:14+00:00

The surface roughness of SKD61 steel is improved by CNC flat grinding method. The optimal flat grinding parameters were investigated using the Taguchi method. Based on Taguchi L₉ experimental results and the ratio value (S/N), the optimal flat grinding parameters are determined as follows: grinding wheel spindle speed of 1600 (rpm), feed rate of 5000 (mm/min), depth of cut of 0.0075 (mm), grinding wheel material Noritake-355x38x127 #60 WA. The surface roughness of SKD61 steel is improved from 0.295 µm to 0.035 µm, corresponding to 88.1%.

FACTORS AFFECTING THE APPLICATION OF STRATEGIC MANAGEMENT ACCOUNTING (SMA) IN MEDIUM AND LARGE ENTERPRISES IN HO CHI MINH CITY

2024-08-28T08:43:53+00:00

Strategic management accounting (SMA) is an important part of management accounting, assisting managers in evaluating and shaping business strategies by providing strategic financial and non-financial information. SMA provides critical insights that help managers make strategic decisions to optimise the enterprise's operational efficiency and competitiveness. However, the application of SMA in Vietnamese enterprises still faces significant limitations, influenced not only by internal factors but also by external factors affecting the businesses. This study indicates that in medium and large enterprises in Ho Chi Minh City, the adoption of SMA is affected by factors such as company scale, employee expertise, information technology proficiency, competitive intensity, and management network

THE IMPACT OF PERCEIVED BENEFITS ON THE INTENTION TO ENGAGEMENT COMMUNITY SERVICE OF FACULTY AT HIGHER EDUCATION INSTITUTIONS

2024-04-25T02:44:17+00:00

Abstract. This study was conducted to elucidate the intention to participate in community service activities of lecturers at higher education institutions by evaluating the influence of Perceived Benefits on behavioral intention . Using survey data of 203 lecturers and structural model analysis (PLS-SEM). Research results show that Perceived Benefits, Perceived Responsibility and Attitude have a positive influence on the intention to participate in community service activities. Furthermore, the study found that two factors: Perception of responsibility and Attitude play a mediating role in the relationship between Perceived Benefits and lecturers' intention to participate in community service activities. The findings of this study provide useful insights for higher education institution administrators regarding the influence of Perceived Benefits on Perceived Responsibility and Attitudes. It increases the certainty in participating in community service activities of lecturers at higher education institutions.

Keywords: perceived benefits, perceived responsibility, community service.