https://jst.vn/index.php/etsd Journal of Science and Technology - Technical Universities Hanoi University of Science and Technology en-US Engineering and Technology For Sustainable Development 3093-3242 https://jst.vn/index.php/etsd/article/view/1139 Lactose intolerance is prevalent in Asia, affects approximately 2/3 of Asian population. Therefore, the market for lactose-free dairy products, which can provide essential nutrients to lactose-intolerant people especially in Vietnam, is promised. In this study, the lactose-free cheese production from Vietnamese raw milk was developed. The conditions of commercial lactase enzyme for lactose hydrolysis were investigated. Lactic acid bacteria were added to the lactose-free milk to reduce the pH and increase the texture and aroma of the product. As results, lactase enzyme should be used at the concentration of 1 mL/L of raw milk in 90 – 120 min at 40-42oC to totally hydrolyse lactose. The fatty acid profile of lactose-free cheese was identified, where the saturated fatty acids are dominant (palmitic acid: 59,245 µg/g cheese, myristic acid: 21,408 µg/g cheese and stearic acid: 16,828 µg/g cheese). The sensory analysis results showed that the sweetness between the lactose-free and normal fresh cheese is significantly different, and the sensorial committee preferred lactose-free cheese to normal fresh cheese. Nevertheless, new cheese product does not contain lactose is completely feasible in terms of technology and the process could be scaled up to pilot scale prior to commercialization Dr. Nghia Nguyen Chinh Mrs. Hang Nguyen Thu Assoc. Prof. Ha Ho Phu Mr. Giang Hoang Mrs. Hanh Nguyen Thi Bich Assoc. Prof. Son Chu Ky Assoc. Prof. Trang Vu Thu Copyright (c) 2026 Engineering and Technology For Sustainable Development https://creativecommons.org/licenses/by-nc-nd/4.0/ 2026-07-20 2026-07-20 36 4 001 007 10.51316/jst.193.etsd.2026.36.4.1 https://jst.vn/index.php/etsd/article/view/1129 Agricultural sustainability involves activities that has to fulfil environmental and public health requirements. Among the criteria for sustainable development, organic agriculture is a primary key to satisfy the above goals because it is different from conventional agriculture that avoid or reduce synthetic agrochemicals use, replacing them with natural based, less toxic and environmentally friendly products. In the pesticide formulations, traditional types such as dust (D), wettable powder (WP), emulsifiable concentrate (EC) or solvent-based solutions (SL) are no more recommended for sustainable agriculture development due to negative effects on humans and the environment. The current development trends in pesticide formulations for such perspective view are applications of new generation types, with high biological activity and safer, low toxicity to mammals and other beneficial organisms. In these formulations, the toxic, non-biodegradable additives/adjuvants ingredients are replaced by natural-derived environmental-friendly ones. In addition, the new technologies are also applied to increase biological efficiency, reduce environmental pollution such as reducing the size of particles (WP to Suspension concentrate); replacing toxic organic solvents with water or water-based formulations and increasing the coverage of applied surface area (EC/SL to Microemulsion/Nano-formulations); reducing wastage and dose rate (D/WP to Controlled-release formulations); and applying combination/mixed formulations such as ZC, ZE and ZW to expand the spectrum of action and reduce spraying. Some new generation of pesticide formulations include Suspension concentrates (SC), Water dispersible granules (WG), Emulsion in water (EW), Micro-emulsion, Combination/mixed formulations, Nano-formulations, Seed treatment formulations etc. Dr. Engr Toan Dao Huy Assoc. Prof. Hoang Dao Van Copyright (c) 2026 Engineering and Technology For Sustainable Development https://creativecommons.org/licenses/by/4.0/ 2026-07-20 2026-07-20 36 4 008 020 10.51316/jst.193.etsd.2026.36.4.2 https://jst.vn/index.php/etsd/article/view/1097 Carbon dots (CDs) are fluorescent nanomaterials with great potential for applications in sensing and imaging. This study explores the synthesis of CDs using a simple, low-cost, and rapid household microwave-assisted approach, utilizing lemon juice and urea as precursors. By modulating the precursor ratio, we obtained two types of CDs with different optical properties: green-emitting fluorescent CDs (g-CDs) and blue-emitting CD (b-CDs). Both particles showed quantum yields of approximately 10%. The synthesis process, conducted under solvent-free and ambient- pressure conditions, demonstrates an environmentally benign and sustainable route compared to conventional hydrothermal methods. Structural and optical characterizations confirmed that precursor ratio control directly influenced the emission behavior of the CDs. Preliminary investigations further revealed that the g-CDs exhibited selective and sensitive fluorescence quenching toward Hg2+ ions indicating their promise as sustainable and cost-effective probes for heavy metal detection. This study highlights the potential of green-synthesized carbon dots for environmental sensing applications, contributing to developing simple early-warning tools for pollution monitoring Mr Diep Vu Xuan Ms Lam Tran Thanh Ms. Nhi Chu Uyen Dr. Hang Bui Thi Yen Copyright (c) 2026 Engineering and Technology For Sustainable Development https://creativecommons.org/licenses/by/4.0/ 2026-07-08 2026-07-08 36 4 021 029 10.51316/jst.193.etsd.2026.36.4.3 https://jst.vn/index.php/etsd/article/view/1321 Fluazinam is a contact fungicide widely used for the control of various plant diseases due to its broad spectrum of activity and multi-site mode of action. However, its extremely low water solubility and potential environmental toxicity require careful formulation design to ensure effective performance and safety during practical application. In this study, fluazinam was formulated into three different formulation types, including suspension concentrate (SC), wettable powder (WP), and water-dispersible granule (WDG), at laboratory scale. Selected co-formulants were applied to improve formulation performance and stability. The prepared formulations were evaluated for physicochemical stability, including active ingredient content and suspensibility, under room temperature and accelerated storage conditions. Acute toxicity was assessed according to OECD guidelines and classified based on GHS 2019 criteria. Although all formulations exhibited low acute toxicity, formulation-dependent differences in toxicological responses were observed. In particular, the SC formulation showed milder and more rapidly reversible effects in inhalation and irritation studies. These results demonstrate that formulation design influences practical exposure characteristics and toxicological behavior beyond the intrinsic properties of the active ingredient. Duy Vu Cong Vu Vu Van Lien Hoang Thi Thuy Le Thi Copyright (c) 2026 Engineering and Technology For Sustainable Development https://creativecommons.org/licenses/by/4.0/ 2026-07-27 2026-07-27 36 4 030 036 10.51316/jst.193.etsd.2026.36.4.4 https://jst.vn/index.php/etsd/article/view/1414 This study determined the concentrations of seven polybrominated diphenyl ether (PBDE) congeners — BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, and BDE-209 — in snail samples as representative benthic organisms from West Lake (Ho Tay), Hanoi, Vietnam. Samples were collected across four biannual monitoring campaigns in May 2022, November 2022, May 2023, and November 2023. Total PBDE concentrations (ΣPBDE) ranged from 2.50 to 3.27 µg/kg wet weight, with a cumulative increasing trend of 13.7% over 18 months of monitoring. BDE-209 was the dominant congener (~57% of ΣPBDE), followed by BDE-99 and BDE-47 (~11% each), reflecting inputs from commercial deca-BDE mixtures. Dry-season (November) PBDE concentrations were consistently 3–5% higher than wet-season (May) values, attributed to reduced dilution effects and extended sediment contact time during the dry period. Compared to regional studies, contamination levels at West Lake were relatively low; however, the persistent increasing trend warrants long-term monitoring. These findings provide the first time-series baseline dataset on PBDEs in benthic organisms from West Lake, supporting ecological risk assessment and environmental quality management of urban lakes.. Ms Vu Thu Huyen Thu Huyen Vu Copyright (c) 2026 Engineering and Technology For Sustainable Development https://creativecommons.org/licenses/by-nc-nd/4.0/ 2026-10-07 2026-10-07 36 4 037 046 10.51316/jst.193.etsd.2026.36.4.5 https://jst.vn/index.php/etsd/article/view/1201 This study investigates the influence of various photocatalysts, when incorporated into Regenerated Cellulose composite Membranes (RCMs), on the resulting structural properties and photocatalytic degradation performance. Three distinct composite membranes (RCMP25, RCMP25Cu, and RCMP25Ce) were successfully synthesized via a process involving dissolution of cellulose and subsequent coagulation. The successful incorporation of the catalysts and structure of membrane were confirmed by Fourier-transform infrared spectroscopy, X-ray diffraction, Inductively Coupled Plasma Optical Emission Spectroscopy, and Scanning Electron Microscopy. Notably, elemental Ti mapping further demonstrated a uniform distribution of the catalyst particles across the membrane surface. Differential Scanning Calorimetry analysis revealed that the thermal characteristics of the membranes remained essentially unchanged despite the incorporation of different catalysts. In terms of performance, the RCMP25Cu membrane exhibited significant adsorption capabilities under dark conditions, removing up to 32.3% of Rhodamine B (RhB), and achieved the highest degradation efficiency for Methylene Blue (81.91%). Conversely, the RCMP25Ce membrane displayed superior photocatalytic activity toward RhB, reaching 84.89% degradation after 120 minutes of illumination under a Xenon lamp (95% visible light). Therefore, the RCMs exhibit remarkable versatility, enabling the incorporation of diverse photocatalysts for the adsorption and degradation of cationic pollutants without altering their structural integrity, phase composition, and morphology. This research highlights the potential of sustainable cellulose-based platforms for advancing next-generation composite membranes in water treatment applications. MSc. Vi Nguyen Quynh MSc. Thu Truong Minh Dr. Mai Nguyen Ngoc Copyright (c) 2026 Engineering and Technology For Sustainable Development https://creativecommons.org/licenses/by/4.0/ 36 4 047 054 10.51316/jst.193.etsd.2026.36.4.6 https://jst.vn/index.php/etsd/article/view/1227 Toxic dyes represent a critical environmental issue that requires effective treatment due to their direct and indirect impacts on human health. In this experimental study, ZnO nanomaterials were successfully synthesized via a green approach, and several influencing parameters - including stirring temperature, calcination temperature, and calcination time - were systematically investigated, resulting in superior degradation efficiency toward Methylene blue (MB) and the establishment of an optimized synthesis procedure. The phase structure and material properties of ZnO were characterized using X - ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), and UV-Vis light absorption analysis in photocatalytic processes, providing information on particle size, crystalline phase, optical band gap energy, and photocatalytic performance. The results show that the studied parameters significantly affect the characteristics and photocatalytic efficiency of ZnO. Specifically, they show that the ZnO nanomaterials had an average crystal size ranging from 35-40 nm. The ZnO sample at 450 °C showed relatively uniform spherical particles with high porosity, evenly dispersed on the material surface. The band gap energies of the material ranged from 3.19-3.26 eV, which was lower than the Eg of typical ZnO (3.37 eV). The photocatalytic efficiency of MB degradation achieved by the material calcined at high temperatures from 450–700 °C was higher than that of ZnO material calcined at low temperatures. The highest photocatalytic efficiency of MB degradation was achieved by the ZnO sample calcined at 450 °C, reaching 80.85% after 90 minutes under UV-Vis light irradiation, with the highest degradation rate constant of 0.0187 min⁻¹. Tien Hoa Lai Dr. Tuyet Mai Nguyen Thi Assoc. Prof. Ngoc Dung Ta Dr. Lan Anh Luu Thi Assoc. Prof. Dang Chinh Huynh Copyright (c) 2026 Engineering and Technology For Sustainable Development https://creativecommons.org/licenses/by/4.0/ 2026-06-25 2026-06-25 36 4 055 063 10.51316/jst.193.etsd.2026.36.4.7 https://jst.vn/index.php/etsd/article/view/1127 Drying efficiency strongly depends on the uniformity of airflow distribution within the drying chamber. In the study, two-dimensional Computational Fluid Dynamics (CFD) simulations were employed to analyze airflow behavior in a multi-tray drying chamber with six geometric configurations characterized by different frame steps (S). The results reveal that airflow uniformity decreases with chamber height, with pronounced instabilities observed at the upper frames. The value of S was found to play a critical role in airflow distribution. The most popular design of case I with zero-step (baseline) exhibited the poorest performance, with relative standard deviation (RSD) exceeding 55.6% and the largest inhomogeneity with max to min discrepancy (M2M up to 12.5), indicating strong airflow irregularity. In contrast, case V with the tuned vertical step of frame at 30 mm demonstrated the best performance, with RSD as low as 18.7–28.1% and minimal M2M differences, reflecting highly uniform airflow across the tray surfaces. The bigger absolute value of step gave better performance than the smaller ones because the drying airflow tends to follow the surface of trays. Compared to previous studies, these findings underscore the importance of evaluating airflow directly at the tray surfaces rather than solely at the chamber scale. Overall, the study offers practical guidance for optimizing tray arrangement and frame step design to improve airflow uniformity, thereby enhancing drying performance and product quality. Dr. Engr Trung Nguyen Duc Dr. Engr Giang Nguyen Truong Engineer Thao Nguyen Thi Dr. Engr Hieu Nguyen Trung Mrs Anh Nguyen Thi Ngoc MSc Cuong Le Ngoc M Huong Pham Thanh MSc Thuy Phan Minh Dr. Engr Hoang Nguyen Ngoc Copyright (c) 2026 Engineering and Technology For Sustainable Development https://creativecommons.org/licenses/by-nc/4.0/ 2026-06-22 2026-06-22 36 4 064 069 10.51316/jst.193.etsd.2026.36.4.8 https://jst.vn/index.php/etsd/article/view/1141 Simulation is a widely used tool in medical physics, enabling a deeper understanding of intrinsic physical phenomena within systems. In medical physics, simulation is considered essential for research and training due to the unique nature of medical physics equipment, such as X-ray imaging, tomography, and radiotherapy devices, which are used for human diagnosis and treatment. Ethical constraints prevent the use of human subjects in experimental research and training, necessitating the use of phantoms that closely mimic human anatomy. However, measurements on phantoms do not fully replicate radiation interactions with human tissue, highlighting the need for simulation combined with experimental measurements to enhance the accuracy and effectiveness of diagnosis and treatment in medical physics. This article presents the development of medical physics simulation software with an intuitive, user-friendly graphical interface. The software supports medical physics engineers in professional training and research, optimizing diagnostic and radiotherapy techniques to improve the quality of patient diagnosis and treatment. MSc. Ha Bui Ngoc MSc. Thuy Mai Dinh Dr. Thuy Duong Tran Copyright (c) 2026 Engineering and Technology For Sustainable Development https://creativecommons.org/licenses/by-nc-sa/4.0/ 2026-07-08 2026-07-08 36 4 070 077 10.51316/jst.193.etsd.2026.36.4.9 https://jst.vn/index.php/etsd/article/view/1183 The composite ply is made up of two basic components, the fiber and the matrix. The plies are placed together in a mold in a certain order to form a composite laminate. This study presents a method for analyzing the mechanical response of a composite beam from microscopic calculations of the fiber and the matrix. Through the micromechanics and the semi-empirical method to calculate the material properties of the composite ply, using the classical lamination theory (CLT) and the improved Tsai-Wu strength theory to calculate the properties of the composite laminate. Then, using the Euler-Bernoulli beam theory to calculate the mechanical response such as stress, displacement, and safety factor of the composite beam. The results are compared with the experimental results, showing a good agreement. Mr Thuc Nguyen Xuan Assoc. Prof. Tuan Nguyen Anh Mr Huy Nguyen Van Dr. Engr Nam Nguyen Hai Dr. Engr Quang Duong Van Copyright (c) 2026 Engineering and Technology For Sustainable Development https://creativecommons.org/licenses/by/4.0/ 2026-07-16 2026-07-16 36 4 078 086 10.51316/jst.193.etsd.2026.36.4.10 https://jst.vn/index.php/etsd/article/view/1295 The rapid expansion of high-frequency radar systems and satellite communications demands a new generation of electromagnetic (EM) absorbers that break the traditional trade-off between attenuation efficiency and physical thickness. Conventional ferrite-based composites often require prohibitive thicknesses ( ) to achieve impedance matching at lower frequencies, limiting their applicability in weight-sensitive aerospace platforms. This study presents a rigorous multi-objective optimization framework applied to a massive library of 51,182 potential candidates, leveraging high-throughput computational screening and machine learning to identify ultra-thin, high-bandwidth absorbers. By employing Pareto frontier analysis, we isolate a discrete set of "best-in-class" materials capable of achieving a Reflection Loss (RL) exceeding at thicknesses as low as , effectively circumventing Snoek's limit constraints. Beyond simple performance metrics, we introduce a comprehensive robustness analysis, verifying that top-tier candidates maintain their absorption efficacy under simulated manufacturing tolerances ( lattice strain). Furthermore, ternary stoichiometric mapping reveals a critical design rule: optimal broadband performance ( ) is driven not by maximizing magnetic content alone, but by a synergistic balance of magnetic, dielectric, and conductive phases. The result is a validated, actionable Selection Logic Tree that translates complex informatics data into clear synthesis criteria, providing a roadmap for the experimental realization of next-generation low-observable materials. Dr Duc To Anh Dr. Thang Bui Hung Copyright (c) 2026 Engineering and Technology For Sustainable Development https://creativecommons.org/licenses/by/4.0/ 2026-07-07 2026-07-07 36 4 087 095 10.51316/jst.193.etsd.2026.36.4.11 https://jst.vn/index.php/etsd/article/view/1009 This study investigates the influence of various personal factors on individual fashion style. A quantitative research approach was employed using a questionnaire survey conducted with 813 participants aged 18 to 60 in Bac Giang province, Vietnam. The data were analyzed using descriptive statistics and exploratory data mining techniques with the Random Forest algorithm. The examined factors include gender, age, weight, height, skin tone, hair color, marital status, lifestyle preferences, occupation, income, among others. The results indicate that variables such as age, weight, height, income, and amount spent on fashion significantly influence personal fashion style. The study contributes to building a scientific foundation for the development of fashion product strategies that better meet the needs of Vietnamese consumers. Assoc. Prof. Le Nguyen Thi Ms Tu Nguyen Thi Thanh Assoc. Prof. Trinh Nguyen Nhat Copyright (c) 2026 Engineering and Technology For Sustainable Development https://creativecommons.org/licenses/by-nc/4.0/ 2026-05-26 2026-05-26 36 4 096 104 10.51316/jst.193.etsd.2026.36.4.12 https://jst.vn/index.php/etsd/article/view/1230 Menstrual panties, sanitary pads, menstrual cups and tampons are essential products to protect women's health during menstruation. Menstrual panties and cloth sanitary pads are currently highly appreciated because they ensure health and hygiene for women's bodies, can be reused, helping to limit waste to the environment. This article presents the research on the application of new textile materials and technology to panties and sanitary pads to ensure women's menstrual health according to sustainable development. A terry cotton knitted fabric with a spatial structure was used as an absorbent and menstrual fluid storage layer. A polyester textured knitted fabric with good absorbency and capillary properties, quick drying was the inner layer in directly contact with the wearer's body. A waterproof knitted fabric was the two outer layers to prevent fluid from moving out. The adhesive method and seam tape were applied to connect the textile layers ensuring the seams were also waterproof. Four samples of menstrual panties and cloth sanitary pads with different thicknesses of fluid storage layer were created, tested and evaluated. The evaluation results show that the panties and pads samples can absorb and contain up to 50 ml of liquid without leakage to the outer surface. The results also show that the product samples can be easily cleaned and dried quickly. These research results are the basis of the commercial development of menstrual panties and cloth sanitary pads products in sustainable trend. Dr. Ngoc Nguyen Thi Thuy Ms. Trang Ngo Thi Thu Prof., Dr. Huong Chu Dieu Copyright (c) 2026 Engineering and Technology For Sustainable Development https://creativecommons.org/licenses/by-nc/4.0/ 2026-06-23 2026-06-23 36 4 105 112 10.51316/jst.193.etsd.2026.36.4.13 https://jst.vn/index.php/etsd/article/view/1236 While Vietnamese e-commerce has quickly integrated AI tools into customer service, the actual uptake of chatbots hinges on how shoppers in this market appraise their value and experience. In Vietnam, where online shopping is growing rapidly, little empirical evidence exists on the drivers of chatbot adoption. This research aims to investigate the behavioural, psychological, and technological factors that determine Vietnamese consumers’ intention to use AI chatbots in e-commerce customer service. Specifically, it seeks to identify the most influential determinants of usage intention and to propose managerial implications for improving chatbot design and implementation in Vietnam’s digital marketplace. The research was conducted based on a Technology Acceptance Model (TAM) framework incorporating Trust, Social Influence, Application Design, Efficiency, and Enjoyment. Data from 304 online shoppers were analyzed using reliability assessment, Exploratory and Confirmatory Factor Analyses (EFA and CFA), and Structural Equation Modeling (SEM) for hypothesis testing. This process ensured measurement validity and offered theoretical insights into chatbot adoption in Vietnam’s e-commerce context. The analysis reveals that Perceived Usefulness and Perceived Enjoyment serve as the most influential determinants of behavioral intention, whereas Social Influence and Efficiency affect intention indirectly via usefulness, with Trust and Application Design demonstrating comparatively weaker impacts than anticipated. The evidence adds an emerging-market perspective and indicates concrete levers (utility, responsiveness, and engaging interaction) that Vietnamese platforms can act on. Dr Trang Ha Thi Thu Mr Viet Phan Nguyen Ha Copyright (c) 2026 Engineering and Technology For Sustainable Development https://creativecommons.org/licenses/by/4.0/ 2026-08-04 2026-08-04 36 4 113 122 10.51316/jst.193.etsd.2026.36.4.14 https://jst.vn/index.php/etsd/article/view/1209 There is a continuing increase in emphasis placed on the disclosure of environmental, social, and governance information by organisations. Universities have been traditionally known as places where intellectual inquiry and advances in knowledge are paramount. Therefore, there is an expectation that universities would place much emphasis on the relationship between sustainability and education. Recently, Global Reporting Initiative (GRI) guidelines was employed by universities in Vietnam to disclosure of sustainable development information. Therefore, this study aims to evaluate the ESG disclosure levels of 11 key Vietnamese universities. We used content analysis and the Clarkson Index based on the GRI Standards framework. The results found that the universities can be divided into three groups: Pioneer, Compliant, and Limited ESG disclosure. Also, it is found that sustainability reporting in higher education is still in its infancy, considering quantity and quality in the Vietnamese universities. The information focus equally on environmental, economic, and educational dimensions with limited scopes on social equity. Our research result could be benefits for university management and regulators in enhancing the amount and quality of sustainability information at universities in Vietnam. Keywords: Global Reporting Initiative (GRI), Vietnam, Universities, sustainability reporting. Dung Nguyen Thi Phuong Trong Nguyen Duc Hong Pham Thi Thanh Hang Ta Thi Diem An Nguyen Thi Thu Copyright (c) 2026 Engineering and Technology For Sustainable Development https://creativecommons.org/licenses/by/4.0/ 2026-09-24 2026-09-24 36 4 123 131 10.51316/jst.193.etsd.2026.36.4.15