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This study presents an in-depth investigation into the moisture absorption and mechanical behavior of Glass Fiber Reinforced Polymer (GFRP) composites and adhesive bonded joints under hydrothermal aging conditions. The aim of this research is to assess the effects of moisture exposure and aging cycles on the performance of GFRP composites and their bonded joints. The experimental program involved preparing GFRP composite specimens and adhesive samples with specific thicknesses and subjecting them to hydrothermal aging cycles. Moisture absorption and desorption behavior of the adhesive and composite specimens were evaluated using Fick's law, and equilibrium moisture content and diffusion coefficients were determined. Tensile tests were conducted to assess the mechanical properties of the materials, including elastic modulus, ultimate strength, and ultimate strain. The results demonstrated that both the adhesive and GFRP composite exhibited continuous moisture absorption and desorption behavior, following Fick's law. The moisture uptake reached a saturation point, indicating equilibrium moisture content. The diffusion coefficients of the composite were found to be significantly influenced by the saturated moisture concentrations, highlighting the role of the fiber/matrix interface. Furthermore, the mechanical properties of both the adhesive and GFRP composite were evaluated under hydrothermal aging conditions. The elastic modulus of the adhesive increased after the first aging cycle, indicating the completion of the curing process. However, subsequent cycles resulted in reduced mechanical properties due to plasticization, molecular network changes, and swelling caused by moisture. The GFRP composite exhibited a reduction in ultimate strength and elastic modulus with increasing aging cycles, along with a decrease in strain. The study revealed that the moisture absorption affected the failure modes of the bonded joints, leading to a transition from fiber failure to adhesive failure. Hybrid bonded joints, incorporating pins to distribute stress, exhibited improved stability and higher ultimate loads compared to simple joints. This work contributes to the existing body of knowledge by providing a comprehensive understanding of the moisture absorption/desorption behavior and mechanical properties of GFRP composites and adhesive bonded joints under hydrothermal aging. The findings highlight the need for further investigation into the underlying mechanisms, long-term durability, and development of moisture barrier coatings to enhance the performance of GFRP composites in challenging environmental conditions. [ABSTRACT FROM AUTHOR]

The purpose of this interventional experimental study was to determine the effect of health education program on physical activity and blood pressure in middle-aged women with pre-hypertension in Kohdasht. Eighty middle-aged women with pre-hypertension were selected and divided into two groups randomly. After the one-month online training program for intervention group, by conducting an interview, the data was completed using questionnaire and it was analyzed using spss 27 software (significance level of 0.05). Before the intervention, there was no significant difference between the two groups. After 3 months of follow-up, a significant increase in attitude, perceived behavioral control and behavioral intention related to physical activity was observed in the intervention group compared to the control group (P <.05). Also, the average blood pressure in the intervention group was higher than the control group. Considering the effect of the online health education program based on the theory of planned behavior in improving the stages of changing physical activity and reducing blood pressure, the use of these developed models with an emphasis on modifying the subjective norm related to physical activity in the field of prevention is recommended for high blood pressure. [ABSTRACT FROM AUTHOR]

Introduction: Today, internet usage has become an integral part of daily life, but excessive use can harm sleep quality. This study aims to explore the relationship between internet addiction and sleep quality among students at Ilam University of Medical Sciences in 2023. Material & Methods: In 2023,400 students from Ilam University of Medical Sciences participated in this study. They were selected using simple random sampling and met the study criteria. Data were collected through Young's Internet Addiction Test (IAT) and the Pittsburgh Sleep Quality Index (PSQ1). Simple and multiple regression analyses were conducted with a significance level of a ≤ 0.05. Results: The findings showed that 320 (80%) of students exhibited mild to severe internet addiction, with an average total sleep quality falling within the poor range (6.30 ± 2.51). Subjective sleep quality was particularly poor (2.03 ± 0.662) compared to other dimensions (p > 0.05). Simple linear regression revealed significant associations between mild (coefficient = 1.03; p = 0.002) and moderate (coefficient = 2.05; p < 0.001) internet addiction and poor total sleep quality, compared to normal individuals. Additionally, graduate students had better sleep quality than undergraduates (coefficient = -1.03; p = 0.016). Multiple regression analysis, adjusted for educational level, confirmed the association between mild (coefficient = 0.98; p = 0.003) and moderate (coefficient = 1.97; p < 0.001) internet addiction and poor total sleep quality. Conclusion: Internet addiction is linked to poor sleep quality among Ilam University of Medical Sciences students, especially undergraduates. It underscores the need for interventions to raise awareness about internet addiction and its detrimental effects on sleep quality. [ABSTRACT FROM AUTHOR]

A high step‐up non‐isolated DC–DC converter based on a switched‐inductor/switched‐capacitor network is proposed in this paper. The proposed converter takes advantage of both active and passive switched inductor cells. Inductors L1 and L2 can be connected in series to increase the voltage gain. Furthermore, the conduction losses of the proposed converter are low which leads to an increase in its efficiency. The proposed converter takes advantage of the voltage multiplier at the output. As a result, the voltage across all output capacitors is half the output voltage. Moreover, the switched capacitor network in the proposed converter can be extended to achieve higher voltage gain. The comparison is done with other similar topologies in detail to prove the effectiveness of the proposed converter. Operation modes, design procedures, and the control scheme are analyzed. A 200‐W DC–DC converter is implemented and tested. The experimental results confirm the theoretical analysis and its successful operation. The maximum efficiency is above 94%. [ABSTRACT FROM AUTHOR]

In this paper, a high step-up three-level DC–DC converter with a symmetric structure for PV application is proposed. The converter has high voltage gain. This is achieved due to the use of two high step-up cells and two resonant paths in its structure. The converter has low input current ripples and the voltage stress across all switches is equal to half of the output voltage. The proposed converter uses simple pulse–width modulation (PWM) to trigger the switches. Hence, the proposed converter benefits from a simple structure and control circuit. All semiconductor devices are turned on/off under ZCS conditions. Thus, the switching losses are decreased, and the total efficiency is increased. The converter is implemented and tested through a laboratory prototype. The experimental results verify the theoretical analysis. [ABSTRACT FROM AUTHOR]