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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]

In this paper, a multiobjective and simultaneous two-problem allocation of a hybrid distributed generation (HDG) system comprises of solar panels, wind turbines, and battery storage is proposed in a 33-bus unbalanced distribution network which can decrease total losses and improve power quality (PQ). The PQ indices are defined as voltage swell, total harmonic distortion, voltage sag, and voltage unbalance. In this study, the two problems of hybrid system design and its allocation in the distribution network are solved simultaneously. In the allocation problem, the HDG is placed ideally in the network to reduce energy losses and enhance PQ indices. The HDG is measured to minimize the cost of energy generation, including the initial investment, maintenance, and operation costs. The decision variable including the size of HDG components and its location is optimally determined via escaping bird search (EBS) algorithm which is inspired by the maneuvers of the swift bird to avoid predation. The results cleared that the proposed methodology using the wind and solar resources integrated with battery storage reduced the losses, voltage swell, total harmonic distortion, voltage sag, and voltage unbalance by 34.31%, 49.60%, 0.25%, 40.19%, and 2.18%, respectively, than the base network via the EBS and the results demonstrated the better network performance using all renewable resources against wind or solar application only. The outcomes demonstrated the superiority of the EBS in achieving the highest improvement of the different objectives compared with particle swarm optimization (PSO) and manta ray foraging optimization (MRFO). Moreover, the superior capability of the EBS-based methodology is proved in comparison with previous studies. [ABSTRACT FROM AUTHOR]

This paper introduces a new high-step-up, non-isolated switched-inductor switched-capacitor DC-DC converter. The proposed converter remarkably integrates switched-capacitor and switched-inductor cells, leading to a significant increase in voltage gain. This unique composite structure not only ensures the continuity of input current, but also successfully minimizes the current ripple and voltage stress across the components, thereby optimizing efficiency. The standout feature of this converter is its singular switch controlled by pulse-width modulation (PWM), which simplifies its operation. A rigorous steady-state operation analysis is conducted, providing a comprehensive understanding of the converter's performance. For validating the theoretical findings, the paper also details a real-world prototype of the converter. Comparative studies conducted with other similar structures substantiate the superiority of the proposed converter. [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]

This paper proposes the application of a current mode control on a static compensator (STATCOM). The proposed method uses constant switching frequency. Hence, dominant switching harmonics are filtered easily. This approach is also simple and does not need complex calculations. As a result, it will be an ideal candidate for the implementation of controllers or FPGAs. It should be noted that a single‐phase five level reversing voltage (RV) inverter is selected for the STATCOM. The topology has superiorities over conventional multilevel topologies in terms of the control circuit, switching frequency, and the number of components. The simulation results by MATLAB/Simulink prove successful mitigation of voltage sag by the proposed approach. A prototype based on the proposed method is also developed and examined successfully to evaluate voltage sag mitigation. The harmonic spectrum of the STATCOM is also presented to illustrate the equipment compatibility with IEEE 519 harmonic standard. [ABSTRACT FROM AUTHOR]

A high step‐up DC–DC converter which is applied to a voltage lift capacitor and coupled inductors to increase the voltage gain is proposed in this study. Moreover, the interleaved structure is applied in the converter to decrease the input ripple current. Besides, the voltage stress across the main and auxiliary switches is low. Furthermore, all switches and diodes have the soft‐switching condition by using an active clamp auxiliary cell. Consequently, the proposed converter has a high efficiency which is ideal for photovoltaic applications. Energy stored in the coupled inductors is transferred to the voltage lift capacitors and then transmitted to the output. Therefore, no voltage spikes caused by leakage inductors are created on the main switches. The converter operates in continuous current mode and its control remains in pulse width modulation. A 210 W laboratory prototype of the converter with 40 V input voltage and 420 V output voltage under 100 kHz switching frequency is constructed and experimental results confirm the theoretical analysis. Low voltage stress, low input ripple current and high efficiency (96.5%) show the superiority in the operation of the proposed converter in comparison with other similar structures. [ABSTRACT FROM AUTHOR]

Summary: This paper proposes a novel cost‐effective feature as a three‐phase four‐switch inverter utilizing a modified quasi Z‐source (MQZs) network. This inverter exploits a pulse‐width modulation (PWM) control strategy based on developed space vectors to provide balanced three‐phase output voltages and currents. It also has many applications such as the three‐phase induction motor (IM) with adjustable speed drive (ASD) fed by a DC and/or rectified AC supply. Unlike some other similar four‐switch inverters or converters, which can only work in step down (buck) mode or step up (boost) mode, this inverter can operate in both modes that depend on switching signals and due to adjusting the zero shoot‐through (Zsh‐th) duty cycle. It also decreases the total harmonic distortions (THD) of output voltages and currents. The MQZs inverter reduces the switching losses and the cost of topology in comparison with the conventional six‐switch topologies. The utilized control strategy can work well without any extra filtering circuit in DC side to eliminate the effect of the DC‐bus voltage ripples on the inverter output currents and voltages. The experimental results are found closely analogous and confirm the aforementioned features of the proposed topology compared with other traditional topologies, although the inverter output filter is a conventional LC filter. [ABSTRACT FROM AUTHOR]

The utilization of a single-phase Quasi-Z-source AC/AC converter for voltage sag mitigation is introduced in this paper. The suggested topology can compensate voltage sag up to 50%, which is an advantage in comparison with traditional structure, as most voltage sags are not more than 50%. The suggested topology has superior characteristics compared to the conventional topologies and has the following specifications: using the same ground for sharing output and input voltages; functioning in the continuous current mode; employing direct AC/AC converter; applying safe-commutation scheme; the ability to expand of the output voltage range increasing reliability and reducing the harmonics in the output voltage. Because of using safe commutation strategy, as shown in results, no ripple and spike exist in the output voltage. The hardware prototype of the offered structure has magnificently been developed to obtain the experimental results. The experimental results were obtained based on the resistive and inductive loads for a few different sags in the input voltage. The results presented showed good performance despite the simplicity in the control scheme. Moreover, they confirm the good performance of the proposed topology. [ABSTRACT FROM AUTHOR]

In this paper, a fully soft-switched bidirectional dc–dc converter is proposed. All semiconductor devices are soft switched, while its control circuit remains pulsewidth modulated. This condition is achieved only by one auxiliary switch. So, the proposed topology has less complexity in comparison with other similar structures. The energy conversion through the proposed topology during buck and boost modes is highly efficient due to achieved soft-switching condition. The auxiliary circuit operates once during each switching cycle. The converter is analyzed and a 250-W laboratory prototype of the proposed converter is constructed. The experimental results are presented that confirm the theoretical analysis. [ABSTRACT FROM AUTHOR]

This paper investigates a time-to-digital converter (TDC) that employs interpolation and time stretching techniques for digitizing the time interval between the rising edges of two input signals as well as increasing the resolution. In the proposed TDC, interpolation is performed based on a dual-slope conversion. The proposed converter eliminates the comparator offset voltage error and the comparator parasitic capacitor error compared with the TDCs that have been proposed previously. The features of the converter consist of the high accuracy and high resolution due to elimination of errors and usage of the analog interpolation structure. Moreover, it does not use gated delay lines in its structure and has the advantage of low sensitivity to the temperature, power supply and process (PVT) variations. For validation, the proposed TDC is designed in TSMC 0.18 μ m CMOS technology and simulated by Hspice simulator. The comparison between the theoretical and simulation results confirms the benefits of the proposed TDC operation. The results prove that it can be employed for high speed and resolution applications. [ABSTRACT FROM AUTHOR]

This study proposes a new interleaved pulse width modulation boost converter that uses only one auxiliary switch in its structure to create soft-switching condition for all semiconductor elements. This way leads that the proposed converter has a simpler structure in comparison with other similar interleaved topologies. Moreover, the auxiliary circuit is not located in the main power path from input to the output. So, the current rate of the elements in the auxiliary circuit is very low. Due to soft-switching condition for all semiconductor elements, the proposed topology has low power losses and high efficiency. The efficiency of the converter is 97.6% at full load range. Besides, using the interleaved structure in the proposed converter leads to lower current stresses on the circuit elements. A 120 W prototype of the proposed converter is implemented. The experimental results confirm the aforementioned advantages of the proposed converter such as high efficiency in comparison with other similar topologies. [ABSTRACT FROM AUTHOR]

Summary: This paper proposed a new single‐ended primary inductor converter (SEPIC)‐boost DC‐DC converter that uses only one auxiliary switch to create soft switching condition for all semiconductor devices. The auxiliary circuit comprises one power switch (Sa), one resonant inductor (Lr), one resonant capacitor (Cr), and one diode (Do2). The auxiliary switch (Sa) controls the resonance during switching instants. The converter has simple structure and its control circuit remains pulse width modulation (PWM). Besides, the proposed converter has high voltage gain without using any transformer or coupled inductors. In addition, the auxiliary switch is not located in the main power path. Moreover, using soft switching techniques is the best way for reducing the size, weight, and volume of the converter. Furthermore, reduction of input inrush current and voltage stress for the main switch is obtained by using SEPIC‐boost structure. A laboratory prototype converter is designed and implemented. The experimental results presented confirm the theoretical and features of the proposed converter. This paper proposed a new SEPIC‐boost DC‐DC converter that uses only one auxiliary switch to create soft switching condition for all semiconductor devices. The soft switching condition causes reduction of the converter losses and result in increment of its efficiency. [ABSTRACT FROM AUTHOR]

Power quality is one of the key features in developing electric networks. It has been noticed because of its impact on economy and reliability of electrical networks. There are several power quality phenomena which are categorised in recent standards and literatures. Among them, voltage sag is more common and destructive for electric networks and consumers. This article presents a new detection method to monitor voltage sag in different electric network conditions. Goertzel algorithm is shown to be effective and simple for sag measurement compared to available sag detection methods. In order to increase the detection speed and response time, the Goertzel algorithm is modified. This modification will add to the speed of sag detection. The feasibility of the proposed method is justified through a measurement set-up developed using the dSPACE R1104 Digital Signal Processor Platform. The experimental results prove that sag measurement speed is improved by twice using the proposed modified Goertzel algorithm in comparison with the original method and some established methods. The results also verify that the sag detection of the proposed method is not affected by harmonic distortion of the voltage waveform. [ABSTRACT FROM AUTHOR]

Brief epochs of beta oscillations have been implicated in sensorimotor control in the basal ganglia of task-performing healthy animals. However, which neural processes underlie their generation and how they are affected by sensorimotor processing remains unclear. To determine the mechanisms underlying transient beta oscillations in the LFP, we combined computational modeling of the subthalamopallidal network for the generation of beta oscillations with realistic stimulation patterns derived from single-unit data recorded from different basal ganglia subregions in rats performing a cued choice task. In the recordings, we found distinct firing patterns in the striatum, globus pallidus, and subthalamic nucleus related to sensory and motor events during the behavioral task. Using these firing patterns to generate realistic inputs to our network model led to transient beta oscillations with the same time course as the rat LFP data. In addition, our model can account for further nonintuitive aspects of beta modulation, including beta phase resets after sensory cues and correlations with reaction time. Overall, our model can explain how the combination of temporally regulated sensory responses of the subthalamic nucleus, ramping activity of the subthalamic nucleus, and movement-related activity of the globus pallidus leads to transient beta oscillations during behavior. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes the design and implementation of zero voltage transition (ZVT) pulse width modulated (PWM) bidirectional buck–boost converter. The simplicity of the control and the reduction of voltage and current stresses on the main switches are the main features of the proposed converter. The additional component of the converter consists of two auxiliary switches and coupled inductors. They provide a zero voltage switching condition for all switching elements regardless of the power flow direction, making the energy conversion highly efficient. The calculated efficiency of the suggested converter is more than 96% at full load in both buck and boost modes. In addition, the same auxiliary circuit can be used in other basic non-isolated bidirectional converters such as Cuk, Sepic/Zeta, buck–boost/buck–boost and cascade buck–boost converters to provide soft switching. A 100 W prototype of the proposed converter is implemented. The simulation and experimental results are found closely comparable and confirm the effectiveness of the proposed method. [Copyright &y& Elsevier]

Abstract: This paper presents a high efficiency non-isolated bidirectional converter which can be employed as an interface circuit between ultracapacitors or batteries and DC bus voltage. All semiconductor devices in the proposed converter are soft switched while the control circuit remains PWM. So, the energy conversion through the converter is highly efficient. The proposed converter acts as a zero-voltage transition (ZVT) buck to charge an ultracapacitor or battery and acts as a ZVT boost to discharge an ultracapacitor or battery. The performance of the proposed converter with respect to abrupt load and operating mode change is shown through computer simulation results. The results confirm the aforementioned advantages and features of the proposed converter. [Copyright &y& Elsevier]

Introduction: The study of nutritional status and children growth monitoring can play an important role in the diagnosis of developmental disorders in the early stages of life. Accordingly, the purpose of this study was to examine the growth chart and nutrition supplements in children of 6-12 months old in Ilam. Materials and Methods: This study was performed using data from 200 health records of children aged 6-12 months who referred to Ilam health centers in 2017. The sampling method was multistage cluster sampling. Weight measurement performed in kilograms and height and head circumference measured in cm and all specimen measurements performed in identical conditions. Data analysis carried out using SPSS.21 with a confidence level of 0.5. Results: Out of 200 cases, 89(44.5%) were male and 111(55.5%) were female. The mean age was 9.44 ± 1.23 months. Among investigated children, 39% (78children) in terms of weight to age index, 18.5% (37children) in terms of height to age index of developmental delay, and 24% (48children) in terms of head circumference to the age had undesirable growth. In addition, 55.5% of children had started baby food in an improper time. In addition, 44.5% were breastfed. The findings demonstrated that there is a significant difference in the weight to age index in terms of gender (p=0.024). Moreover, height and head circumference to age indices had a statistically significant relationship with weight to age index (p<0.05). Conclusion: Underweight cases in boys were more than girls and chronic malnutrition in girls was higher than boys. Therefore, long-term studies are needed for more accurate evaluations. [ABSTRACT FROM AUTHOR]