SECURITY CAPABILITY ANALYSIS OF COGNITIVE RADIO NETWORK WITH SECONDARY USER CAPABLE OF JAMMING AND SELF-POWERING

This paper investigates a cognitive radio network where a secondary sender assists a primarytransmitter in relaying primary information to a primary receiver and also transmits its own information toa secondary recipient. This sender is capable of jamming to protect secondary and/or primary informationagainst an eavesdropper and self-powering by harvesting radio frequency energy of primary signals.Security capability of both secondary and primary networks are analyzed in terms of secrecy outageprobability. Numerous results corroborate the proposed analysis which serves as a design guidelineto quickly assess and optimize security performance. More importantly, security capability trade-offbetween secondary and primary networks can be totally controlled with appropriate selection of systemparameters

Primary pulmonary T-cell lymphoma mimicking asthma and community-acquired pneumonia: a rare case report

Primary pulmonary T-cell lymphoma (PPTL) is a rare disease. Diagnosing PPTL is challenging due to non-specific clinical symptoms and imaging. A 32-year-old female presented with persistent fever, cough, and dyspnoea. The symptoms were initially treated as asthma and community-acquired pneumonia without improvement. Chest computed tomography (CT) revealed bilateral consolidations with a CT angiogram sign, and flexible bronchoscopy showed infiltrative lesions causing bronchial stenosis. Histopathological examination of the tissue biopsy identified T-cell lymphoma through immunohistochemical staining positive for CD3. This case highlights the importance of considering differential diagnoses such as PPTL in patients with atypical presentations of asthma or non-resolving pneumonia. This case also demonstrates the diagnostic utility of flexible bronchoscopy in identifying airway obstruction due to malignant cells, which can mimic asthma

WATER QUALITY STATUS OF WHITE LEG SHRIMP FARMING AREAS IN BINH DAI DISTRICT, BEN TRE PROVINCE, VIETNAM

This study focused on water quality assessment of farmed shrimp ponds in Binh Dai District, Ben Tre Province. The goals of the study were to provide chemical parameters of pond water for farmers, to identify problems and causes in farmed shrimp related to water quality and disease, and to help managers find appropriate solutions to minimize damage to local shrimp farming. Water samples were collected monthly from January to June 2021 from 90 vannamei farmers in six different areas, including Vang Quoi Dong, Dinh Trung Binh Thoi, Phu Long, Phu Vang, and Binh Thang of Binh Dai District. Parameters investigated in this study included pH, alkalinity, NH4+, NH3, NO2- and three other minerals. Water quality parameters were analyzed based on APHA standard analysis methods. The results showed that the water quality of shrimp farming areas in Binh Dai fluctuated from time to time, and water quality parameters were suitable for vannamei shrimp farming. However, the concentration of NO2- was always higher than the permitted threshold. The results from cluster analysis and MANOVA testing showed that water quality of the shrimp farming areas in Binh Dai was significantly different (p < 0.05), especially NO2-, Ca, Mg and alkalinity. These findings suggest that farmers must apply proper solutions for water quality management in each farming area to maximize crop production

ẢNH HƯỞNG CỦA CÔNG NGHỆ THỰC TẾ ẢO TĂNG CƯỜNG ĐẾN Ý ĐỊNH MUA HÀNG TRỰC TUYẾN CỦA NGƯỜI TIÊU DÙNG

The study shows the effects of factors affecting consumers' purchase intention after experiencing Virtual Try-on (VTO) in Vietnam. The study is carried out by quantitative method through data from 408 subjects of different ages in Hanoi and Northern provinces. The findings of the study demonstrate that perceived usefulness, perceived ease of use, perceived enjoyment, and perceived privacy risk, have a significant impact on users' attitudes toward Virtual Try-On (VTO). Consequently, these factors increase their influence on customers' purchase intentions. Based on these results, the research group recommends that, in practical settings, enterprises concentrate on providing high-quality services, promoting their products to augment the aforementioned factors, and simultaneously addressing users' attitudes to enhance the overall customer experience. Therefore, this study provides valuable insights into the factors that influence customers' attitudes toward VTO technology, thereby contributing to the existing literature on the topic.Nghiên cứu chỉ ra những tác động của các nhân tố ảnh hưởng tới ý định mua hàng của người tiêu dùng qua hành vi sử dụng công nghệ trải nghiệm sản phẩm trực tuyến (Virtual Try-on - VTO) tại Việt Nam. Phương pháp định lượng được sử dụng để phân tích dữ liệu từ 408 đối tượng trong nhiều độ tuổi khác nhau trên địa bàn thành phố Hà Nội và các tỉnh thành phố miền Bắc. Kết quả cho thấy rằng các nhân tố như cảm nhận tính hữu ích, cảm nhận tính dễ sử dụng, cảm nhận tính thích thú, và cảm nhận rủi ro về quyền riêng tư có tác động đến thái độ của người dùng với công nghệ VTO từ đó gia tăng ảnh hưởng tới ý định mua sắm của khách hàng. Nhóm nghiên cứu đề xuất rằng, trong bối cảnh thực tiễn, doanh nghiệp cần tập trung vào cung cấp dịch vụ chất lượng, quảng bá sản phẩm để nâng cao các yếu tố đã được đề cập, đồng thời quan tâm đến thái độ của người dùng để cải thiện trải nghiệm tích cực cho khách hàng

Fabrication and Evaluation of the Photocatalytic, Antibacterial Activity of Ag–TiO2_2 Thin Film

Ag–TiO2 thin film was fabricated by DC magnetron sputtering and photoreduction methods. Characteristics of the film such as surface area, crystal structure, and chemical composition were investigated by using scanning electron microscope (SEM), X–ray diffractometry (XRD) and UV–vis spectra. The photocatalytic activity of Ag–TiO2 thin film was determined by the degradation of methylene blue (MB) solution under various irradiation conditions. The antibacterial property of Ag–TiO2 thin film was conducted in E. coli bacteria. Results showed that the photocatalytic and antibacterial property of Ag–TiO2 thin film are better than those of pure TiO2 thin film in the visible region. Ag–TiO2 thin film shows a great potential application in the antibacterial and environment field

Optimization of metal transfer in rutile flux-cored arc welding through controlled CO₂ concentration in argon–CO₂ shielding gas

Trinh N.Q., Le K.D., Tashiro S., et al. Optimization of metal transfer in rutile flux-cored arc welding through controlled CO₂ concentration in argon–CO₂ shielding gas. Journal of Manufacturing Processes 124, 590 (2024); https://doi.org/10.1016/j.jmapro.2024.06.047.In this study, we analyzed the impact of carbon dioxide concentration in argon–carbon dioxide shielding gas on droplet transfer characteristics in rutile flux-cored arc welding, employing titanium oxide as a primary wire flux component. The welding process was carried out at a welding current of 190, 220, 250, 280, and 310 A under an argon–CO₂ shielding gas mixture with six levels of CO₂ concentration of 0, 5 %, 10 %, 15 %, 20 %, and 25 % for a parametric study. Unlike the conventional solid wire welding trend, where the droplet transfer frequency decreases with the increase in carbon dioxide concentration, an increase in metal transfer frequency was observed with the increase in CO₂ concentration from approximately 5 % to 20 %. The concentration reaching the maximum frequency was 20 % at 190 A, which decreased as the welding current increased, reaching 5 % at 310 A. Droplet initiation at the lower sheath end is succeeded by a gradual downward movement along the flux column's side after a few milliseconds. Upon reaching the lower end, the droplet forms a neck and undergoes separation. Thus, the length of the flux column directly impacts the duration of one droplet transfer cycle. The length was decreased by arc constriction when increasing CO₂ concentration appropriately to concentrate beneath the flux column or by increasing the welding current to raise the arc temperature, which contributed to melting and shortening the flux column

TiO 2

An improved photocatalytic activity of semiconductor materials using incorporation of the noble metals such as Ag, Au, and Pt is a promising technology. In this study, Ag nanoparticle-TiO2 nanotube structures (Ag-TNTs) have been investigated as a photocatalyst in different irradiation conditions using different characterization techniques. The results indicate that Ag nanoparticles dispersed uniformly on the TNTs’ surface without any change in TNTs’ morphology. In addition, Ag-TNTs exhibited lower photoactivity than the TNTs under UV irradiation. In contrast, Ag-TNTs increased the photoactivity in comparison with TNTs and the photocatalytic performance under sunlight irradiation. These phenomena could be contributed to the appearance of Ag nanoparticles on the nanotube surface

Elucidation of droplet detachment mechanism in metal-cored arc welding

Tashiro S., Trinh Q.N., Le D.K., et al. Elucidation of droplet detachment mechanism in metal-cored arc welding. Journal of Manufacturing Processes 124, 1583 (2024); https://doi.org/10.1016/j.jmapro.2024.07.040.It has been demonstrated experimentally that a globular transfer mode tends to occur in argon gas metal arc welding using a metal-cored wire (called metal-red arc welding (MCAW)) even under conditions where a spray transfer mode occurs when a solid wire is used. This study aimed to elucidate the droplet detachment mechanism in MCAW using numerical simulations. It was observed that in the initial stage of droplet growth, the argon arc attachment (which carried a large portion of the current) was located on the metal sheath surrounding the unmelted flux. Moreover, an eddy containing an upward flow at the wire axis was formed inside the droplet. When this eddy was formed, the droplet volume increased owing to wire melting. However, neck formation did not occur. This is considered to be because only a small portion of the current is conducted through the droplet, and the Lorentz force acting on the droplet is significantly weak. Thereafter, when the droplet grew to a certain extent and the arc attachment moved below the unmelted flux position, the Lorentz force acted strongly and almost uniformly on the droplet. Accordingly, this eddy disappeared, and the flow abruptly transitioned to a downward unidirectional high-speed flow. Consequently, the droplet began to extend downward to form a neck, which caused it to detach. For these reasons, the time required for droplet detachment increased, and the metal transfer frequency decreased compared with the case of the solid wire. This explains the observation that globular transfer persists in metal-cored wires at currents higher than those for which the transition to spray transfer has occurred for solid wires

Eligible CO₂ content in Ar-CO₂ mixture shielding gas for improving metal transfer in metal-cored arc welding

Trinh N.Q., Tashiro S., Le K.D., et al. Eligible CO₂ content in Ar-CO₂ mixture shielding gas for improving metal transfer in metal-cored arc welding. International Journal of Heat and Mass Transfer 231, 125803 (2024); https://doi.org/10.1016/j.ijheatmasstransfer.2024.125803.Metal transfer frequencies in a gas metal arc welding process with a metal-cored wire were quantitatively measured for the first time as a function of the CO₂ content (i.e., 5, 10, 15, 20, 25, 50, and 100%) in argon-CO₂ shielding gas mixtures at welding currents of 220, 250, and 280 A, and the results were compared with those of a solid wire. As a result, the metal transfer frequency of solid wire was monotonically decreased with the CO₂ content owing to an increase in the arc pressure, which prevented droplet detachment. However, the metal transfer frequency of the metal-cored wire presented a maximum value at 15% CO₂ under all the current levels. The transfer behavior was supposed to depend on the relation between the arc attachment position and the tip of the unmelted flux position inside the cored wire. When the CO₂ concentration was low, the arc was attached higher than the unmelted flux, causing the electromagnetic force to be ineffective in droplet separation. When the CO₂ concentration increased slightly, the arc was moved downward to the tip of the unmelted flux. That tendency temporarily facilitated the neck formation at the wire tip due to enhanced electromagnetic force flowing through the molten metal on the wire tip. Nevertheless, when the CO₂ content increased over a critical value, the arc pressure became a dominant factor to hinder the droplet detachment, which caused a decrease in transfer frequency. Consequently, the metal transfer frequency of metal-cored wire became maximum at 15% CO₂

The burden of tuberculosis in Ho Chi Minh City, Vietnam: a spatial analysis of drug-susceptible and multi-drug resistant cases between 2020 and 2023

We characterised the spatial distribution of drug-susceptible (DS) and multi-drug resistant (MDR) tuberculosis (TB) cases in Ho Chi Minh City (HCMC), a major South-East Asian metropolis, and explored demographic and socioeconomic factors associated with local TB burden. Hot spots of DS- and MDR-TB incidence were observed in the central parts of HCMC, with substantial heterogeneity observed across wards. Positive spatial autocorrelation was observed for both DS- and MDR-TB. Ward-level TB incidence was associated with HIV prevalence (incidence rate ratio [IRR] 1.77, 95% CI 1.54-2.03) and the male proportion of the population (IRR 1.05, 95% CI 1.02-1.08). No ward-level demographic and socioeconomic indicators were associated with MDR-TB case count relative to total TB case count. Our findings may inform spatially-targeted TB control strategies and provide insights for generating hypotheses about the nature of the relationship between DS- and MDR-TB in HCMC, Vietnam and the wider South-East Asia region