Design of a Variable Reactor for Load Balancing and Harmonics Elimination

This paper presents the design of a variable inductor with a rotational magnetic core whose position is controlled in a closed-loop system. This magnetic structure facilitates the impedance changes which may be used for load balancing, harmonics elimination, transient response improvement, and as a controlled reactor in static VAr compensation (SVC). The design of the inductor and analysis of its impedance change caused by positioning a movable element are carried out by using the finite element method. As a result, the variation range of the impedance is determined. The proposed variable inductor is compared with a typical SVC reactor. The results show good performances in static var compensation with higher reliability and no harmonics generated. For closed-loop control, a secondorder sliding mode controller is designed for position control of the rotating core via a DC motor. Simulation results of the proposed system present highly robust and accurate responses without control chattering in face of nonlinearities and disturbances

Design of second-order sliding mode controllers for MR damper-embedded smart structures

This paper presents the design of second-order sliding mode controllers for semi-active control using magneto-rheological (MR) dampers. The approach can be useful in applications involving shock absorbers but here our main concern is the suppression of building vibrations induced by dynamic loadings such as earthquakes or strong winds. The MR dampers have been of increasing interest in structural control as they are inexpensive to manufacture and have attractive properties such as small energy requirements, reliability and stability in operations, as well as a fast response of milliseconds. Challenges of MR damper structural control rest with the system's high nonlinearity due to the force-velocity hysteresis, and the constraint of the magnetisation current, required to be between its zero and maximal values. A variety of control algorithms have been applied, including the decentralized bangbang control, modulated homogeneous friction algorithm, clipped optimal control, Lyapunov-based control, and also non model-based intelligent schemes. In these techniques, the currents are usually obtained from the damping force indirectly rather than directly from the controller output. For direct current control, in this paper we propose second-order sliding mode controllers, which can satisfy the control constraint, provide high accuracy, retain robustness and remove chattering. The effectiveness of the proposed direct current control technique is verified, in simulations, on a benchmark building model subject to excitation of various scaled earthquake records

Seismic responses of civil structures under magnetorheological-device direct control

This paper presents an efficient control strategy for magnetorheological (MR) dampers embedded in building structures to mitigate quake-induced vibrations. In this work, MR dampers are used as semi-active devices, taking the advantages of the fail-safe operation and low power requirement. By using a static hysteresis model for the MR damper, a suitable controller is proposed here for direct control of the supply currents of the MR dampers using feedback linearization. The dampers are configured in a differential mode to counteract the force-offset problem from the use of a single damper. The effectiveness of the proposed technique is verified in simulation by using a ten-storey building model subject to quake-like excitations

Relationship between using cell phone and the risk of accident with motor vehicles: An analytical cross-sectional study

Purpose: Traffic accidents are one of the major health problems in the world, being the first cause of burden of illness and the second leading cause of death in Iran. The Sistan-Baluchestan province is one of the most accidental provinces of Iran with the highest rate of accidents-caused deaths. This study was conducted to determine the risk factors associated with traffic accidents in Zahedan through 2013 to 2016. Methods: This analytical cross-sectional study was carried out on 223 drivers from Zahedan who were traumatized by traffic accident and sent to Zahedan hospitals. The data were obtained through interviews taken by the trained interviewers via refereeing to the medical records and collected in the researcher-made checklist. Census was obtained from the study subjects. For data analysis, independent t-test, one-way ANOVA, Chi-square and logistic regression were used with the Stata software version 11.0. Results: In this study, 223 male subjects with the mean age of (32.54 ± 12.95) years, 39.8 single and 60.2 married, entered for investigation. Most accidents (38.8) occurred between 12:00 to 17:59. While driving, 47.1 of the study subjects were using cell phones, 89.1 had manual use of mobile phones, 21.9 had a habit of sending short message service (SMS) and 23.4 had sent SMS within 10 min before the accident. The one way analysis of variance showed that the mean age of individuals with marital status, driving experience, education and accident with motorcycle were significantly different (p < 0.05). Also, the multivariate logistic regression test indicated a significant relationship of smoking, ethnicity, insurance and SMS typing while driving with motorcycle accident (p < 0.05). Conclusion: In this study, SMS and smoking while driving had the highest risk among the variables studied in the motorcycle accidents. Therefore, effective education attempting to enhance people's awareness about the consequences of using cell phone and smoking during driving to reduce traffic accidents seems necessary. © 2020 Chinese Medical Associatio

Identification of the Range of Nursing Skills Used to Provide Social Support for Mothers of Preterm Infants in Neonatal Intensive Care

Background. Hospitalization of preterm infants in neonatal intensive care units (NICUs) is a stressful experience for parents. Iranian NICUs do not have specified levels of care, nor do they integrate supportive methods of parent support such as family-centered care approaches. This study investigated the range and types of neonatal nursing support, as perceived by mothers of preterm infants, and its association with mothers’ satisfaction with infant care in the NICU. Methods. This is a descriptive, correlational study of mothers of preterm infants who were hospitalized in three different NICUs in Iran. A convenience sampling method was used. Data were collected using three questionnaires that identified (i) demographic information; (ii) social support available; and (iii) parent satisfaction with infant care. Results. Mothers (N = 110) generally rated the support from nurses as being moderate. Correlation analysis identified a moderate association of neonatal nurse social support domains for affirmational (r = 0.44) and concrete aid (r = 0.41), a moderately strong association for affectional support (r = 0.64), and total social support (r = 0.60) with mothers’ satisfaction. Conclusion. There were positive associations between social support from nurses and mothers’ satisfaction with the care of their infants. Therefore, planning to promote and create opportunities for neonatal nurses to support mothers in NICU is important to promote increased maternal satisfaction in infant care

The Effect of Foot Serial Casting Along with Botulinum Toxin Type-A Injection on Spasticity in Children with Cerebral Palsy

Abstract: Background & Aims: The goal of this study was to determine the effect of foot serial casting along with botulinum toxin type-A injection on spasticity in children with cerebral palsy. Methods: This study was a randomized clinical trial performed as a pre-post, double blind study. It was performed on 25 children with hemiplegia and diplegia (2-8 years) in Tehran city, who were referred to valiasr rehabilitation foundation. Participants were chosen by simple randomized sampling and were matched for age, Gross Motor Function Classification System (GMFCS) and type. They were randomly divided into two groups. The first group (n=13) underwent BTX-A injection alone and the second group (n=12) had BTX-A injection and foot serial casting after the injection. Clinical assessments were done using the GMFCS and Modified Ashworth Scale before and at 1, 3, 6 and 12 months after the interventions. Data were analyzed by Wilcoxon signed rank test and mann-whitney U. Results: Comparison of two groups in regard to the right and left knee spasticity at, 1, 3, 6 and 12 months after injection showed no significant difference in comparison to those before interventions. Furthermore, comparison of right and left ankle spasticity before injection with that at 1, and 3 months follow ups did not show statistically significant difference, but significant differences were found when compared with 6 and 12 month follow-ups (P<0.05) Conclusion: It seems, one of the proper approaches to reduce spasticity in children with cerebral palsy is foot serial casting along with botulinum toxin type-A injection and it can decrease the muscle tone when applied more than six months. Keywords: Cerebral palsy, Botulinum toxin type A, Muscle spasticity, Casts, Occupational therap

A new hybrid filter for power quality improvement in unbalanced load conditions

This paper presents the design of a new hybrid filter for quality improvement of power systems in unbalanced conditions. This filter includes a variable passive filter in parallel with an active filter. The passive part is designed with a varying inductance to reduce the rating of the active part. By using this proposed filter it is possible to compensate for the current harmonics and unbalanced loads with a lower rating active filter compared with conventional ones. Also a simple and accurate method is used to generate the harmonic reference current in the active part of this filter which makes it efficient in unbalanced load conditions. Furthermore, an intelligent hysteresis band current controller is utilized to generate inverter pulses owing to its quick current controllability and easy implementation. Simulation results using the MATLAB Simulink Power System Toolbox show the efficiency and effectiveness of the proposed hybrid filter in elimination of harmonics and balance of the utility current with a desired level of load balancing. © 2008 IEEE

The effect of an android-based application on the knowledge of the caregivers of children with cerebral palsy

Background: Mobile health and e-learning may have a significant impact on training patients, physicians, students and caregivers. This study aimed to evaluate the effect of using an educational mobile application on the knowledge of the caregivers of children with cerebral palsy (CP). Methods: We used a previously developed mobile application. The knowledge of 17 caregivers of children with CP (including parents) about the daily care of their children was evaluated through a self-assessment and a test with multiple-choice and true-false questions. Next, the application, which included several educational modules for the daily care of the children with CP, was given to the caregivers to use continually for two months. After this period, the knowledge of the caregivers was evaluated by the same tools. Data analysis was performed by SPSS-16, using paired-sample t-test or Wilcoxon test. Results: The effect of the use of this educational application on the knowledge of caregivers in all childcare domains, except for eating, was reported to be significant (p < 0.05). Furthermore, the results of the multiplechoice test revealed that this application increased the knowledge of caregivers in all domains except playing (p < 0.05). Conclusion: Training through novel technologies such as Smartphone along with their applications can improve the knowledge of caregivers about the daily care of children with cerebral palsy