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This study investigated whether neurofeedback (NFB) training and swimming exercise (Swim) would reduce the stress, anxiety, depression, severity of dependence, and cravings in patients addicted to methamphetamines. Participants were allocated randomly to four groups: control group, NFB, Swim, and NFB/Swim. All groups completed the study questionnaire before and after treatment. The NFB, Swim, and NFB/Swim groups reported significantly less stress, cravings, and severity of dependence than the control group. The Swim and NFB/Swim groups had significantly lower depression scores than the control group. Also, the NFB/Swim group experienced less anxiety than the control group. However, the NFB/Swim group had lower levels of stress than the Swim group, and lower levels of anxiety and severity of dependence than the NFB group. These findings suggest that NFB training along with swimming exercise was effective in managing methamphetamine-related behavioral disturbances, which may help patients to manage their cravings. [ABSTRACT FROM AUTHOR]

Switching power converters are integral in various applications like transportation and renewable energy. After their design, ensuring stable closed-loop poles is critical to maintain safe operating conditions. This study focuses on a switching DC-DC boost converter with a cascade control approach using an energy controller for the outer loop and indirect-sliding mode control for the inner loop. The research objective involves investigating stability through eigenvalue evaluation at different operating points. A large-signal average model is applied to make controlled performance independent of the operating point by fixing system poles. Nonlinear controllers, specifically indirect-sliding mode control, are chosen for their robustness, constant switching frequency, and implementation ease. Results indicate that insufficient decoupling leads to eigenvalue displacement, impacting control parameter choices. The research contribution is investigating the local stability of cascaded control, considering its advantageous implications for both performance and design. This study contributes to the understanding of switching power converters' stability, emphasizing the proposed methodology's broader applicability to diverse converter structures. The proposed approach, applicable to various switching power converters, sheds light on the importance of proper decoupling between outer and inner loop dynamics. [ABSTRACT FROM AUTHOR]

Attention to the interaction between instructors and students in engineering education is of remarkable importance. Incorporating practical work alongside theoretical teachings can enhance the effectiveness of learning. In this article, the use of short video-on-demand is introduced as a method of teaching students. An experimental video sample is used, and the interaction between the instructor and students in the classroom while using this video is discussed. As a case study, we investigate the concept of periodic waveforms in a stable system and multiperiodic waveforms in an unstable system, resulting from a change in a control parameter. Although the work is demonstrated on a specific scientific topic, the suggested method can be applied to other scientific subjects. In order to enhance the effectiveness of education, tasks outside the classroom are assigned in addition to in-class activities. The proposed method has been implemented during several academic semesters at the undergraduate and graduate levels, specifically in the fields of mechanical engineering and renewable energy engineering. The results obtained from surveys and evaluations indicate a strong connection with students, understanding and retention of scientific topics. One of the significant advantages of the proposed method is the visualization of educational content through short videos, which enhances the learning process. Among the findings of this study, improvements in skills such as accuracy and the application of engineering reasoning, in addition to scientific knowledge, can be highlighted. [ABSTRACT FROM AUTHOR]

In fuel cell systems, voltage balancing is an important consideration. The utilization of a modular construction based on a three-level boost converter was able to balance DC voltage. This paper investigates the effect of parameter variations, such as inductors and capacitors, on the converter's steady-state controllable areas. The plot of the inductor current and the voltages of the output capacitors are illustrated for different scenarios. The system simulation results were performed using MATLAB / Simulink software. [ABSTRACT FROM AUTHOR]

The lack of uniform production of panels in photovoltaic (PV) systems and snowball effects in fuel cell (FC) systems led us to use a separate dc–dc converter. In addition, in the PV and FC systems, the output voltage is low. Hence, dc–dc boost converters are commonly used in a series connection. Each small unit of a PV or FC operates independently. Therefore, another problem arises in the system that uses the series connection of the converter's output. Owing to the unequal electricity production of the cells, a voltage imbalance occurs at the output terminals. To create voltage balance, a modular structure grounded on a three-level boost converter was investigated. The main objective of this article is to design the control of a modular topology, allowing perfect control of the dc-bus voltage, even with mismatched input powers. The proposed control strategy ensures dynamical properties independent of the operating point, voltage balance, and robust control of the dc output voltage with respect to load perturbations. To ensure the balance of voltages and the control of currents, a sliding mode controller based on indirect synthesis was used. To control the dc–bus voltage, an energy controller is proposed that ensures dynamical performance independent of the operating conditions. The performance in terms of tracking and regulation, as well as its effect on the voltage balance of the output capacitors, was validated through simulations and experimental results. A comparison with a classical proportional integral (PI) approach for controlling the dc-bus voltage was performed. [ABSTRACT FROM AUTHOR]

To balance dc voltage, a two-module structure based on a dc–dc three-level boost converter is utilized. In this article, the possible operating modes for a two-module converter in the steady state are introduced. These modes are performed according to different states of opening or closing of the switches. Total 16 possible operating modes and the operation of different switches in the circuit are shown. The circuits for each operating mode are drawn according to the switch command signals. The relationships governing the system are given in different modes. These equations include the currents through three output capacitors and the inductor voltages of each module. The system is simulated by MATLAB/Simulink. The waveforms of the system are presented in two cases for different operating points. The operating mode of this structure is validated using simulations and experimental results. [ABSTRACT FROM AUTHOR]

This article presents a new modular dc–dc converter topology. As a modular topology, the converter can be used for several energy sources. Each converter module is based on a three-level dc–dc converter, which contains two output capacitors. The first module shares the second capacitor in common with the first capacitor of the next module. In this way, the N-module can be utilized for an N-energy source. The output capacitor voltages are balanced due to the proposed topology and the controller. The controller is based on the indirect sliding mode controller, where the input current of each energy source and the capacitor voltage balancing are taken into account. One of the aims of this article was to obtain the general system relationships for the N-module system. The process of obtaining recurrence equations for the duty cycles of the system is provided for the desired number of modules. Simulation and experimental results are provided to validate the topology. [ABSTRACT FROM AUTHOR]

Voltage imbalance poses a challenge to photovoltaic systems. A modular structure based on a three-level boost converter is proposed to address this problem. The three-level boost converter offers advantages, such as a low current ripple and voltage stress, over a classic boost converter. These advantages offset the use of additional elements in the proposed converter circuit. Two capacitors are used to enable the innovative connection between multiple sources and the three-level boost converter. The second capacitor of the first module is shared with the first capacitor of the second module. This structure is used in conjunction with a controller to balance the voltages in the system. The operating modes of the two-module system in a nominal case are introduced. The controller is based on an indirect sliding model, wherein the input current of each energy source and the output voltage balance are considered. The performance of the current and voltage controllers are studied in two scenarios. The first case involves increasing the reference current and the presence of four sliding surfaces related to the current control and voltage balance, whereas the second case involves the presence and absence of two sliding surfaces related to the voltage balance. The dynamic response of this controller is also compared with the Proportional Integral(PI) controller. Large-signal modeling of the two-module system and the accuracy of this model in two cases of radiation change and panel temperature change is investigated. The robustness of the system is investigated using this large-signal model in two cases that involve changing the inductors and capacitors of the system. A topology consisting of two conventional boost converters is chosen to compare energy stored and efficiency with the proposed topology. The capacitance of the system is calculatedfor two topologies. The energy stored in the two systems is compared. The two-module system is simulated using Simulink MATLAB software. The simulation and experimental results validate the proposed system. [ABSTRACT FROM AUTHOR]

Background: Prevention of noncommunicable diseases (NCDs) during pregnancy is recommended due to severe complications for mothers and infants. Considering that NCDs have a significant impact on infant mortality, this study was conducted to investigate the relationship between mothers' underlying diseases and gestational diabetes and infant mortality in Iran. Materials and Methods: Mothers who referred to the health centers in nine provinces of Iran were included. This case--control study used data collected from pregnant women. There were 1162 cases and 1624 controls. The required data were collected from mothers' health records and through interviews. Results: The chances of neonatal mortality in women with a body mass index (BMI) of 30-35, 1.7 times (odds ratio [OR] = 1.7, confidence interval [CI]: 1.19-2.44, P = 0.003) was higher compared with women with a normal BMI. The chance of neonatal mortality among mothers with high blood pressure was three times higher compared with healthy mothers (OR = 3.04, 95% CI: 1.98-4.65, P < 0.001). The chance of neonatal mortality in women with kidney disease was also 1.64 times higher than mothers without kidney problems (OR = 1.64, 95% CI: 1.1-2.45, P = 0.015). In the study of gestational diabetes, the chance of neonatal mortality among the mothers who had at risk was 1.63 times higher than mothers without gestational diabetes (OR = 1.63, 95% CI: 0.84-3.16, P = 0.014). Furthermore, the chance of neonatal mortality among the mothers who had heart disease was 1.10 times higher than mothers without heart disease (OR = 2.10, 95% CI: 0.88-4.99, P = 0.014). Conclusion: This study showed that undiagnosed underlying diseases were related to neonatal mortality, which highlights the importance of caring for and counseling about the underlying diseases, screening, and controlling blood sugar levels before and during pregnancy to prevent infant mortality by all means possible. [ABSTRACT FROM AUTHOR]