Pulse Compression Probing for Tracking Distribution Feeder Models

A Pulse-Compression Probing (PCP) method is applied in time-domain to identify an equivalent circuit model of a distribution network as seen from the transmission grid. A Pseudo-Random Binary Pulse Train (PRBPT) is injected as a voltage signal at the input of the feeder and processed to recover the impulse response. A transfer function and circuit model is fitted to the response, allowing the feeder to be modeled as a quasi-steady-state sinusoidal (QSSS) source behind a network. The method is verified on the IEEE 13-Node Distribution Test System, identifying a second order circuit model with less than seven cycles latency and a signal to noise ratio of 15.07 dB in the input feeder current.Comment: 5 Pages, 6 Figures, Pending Publication at IEEE PESGM 202

Investigation of the components and antibacterial effects of three plant's essential oil Coriandrum sativum, Achilleh millefolium, Anethum graveolens in vitro

زمینه و هدف: در این پژوهش ترکیبات عمده اسانس سه گیاه گشنیز (Coriandrum sativum)، بومادران (Achillea wilhelmsii) و شوید (Anethum graveolens) شناسایی و اثر ضد میکروبی این گیاهان بر روی چهار باکتری پاتوژن اشیرشیاکلی، باسیلوس سرئوس، باسیلوس لیچنی فورمیس و سودوموناس آئروجینوزا در شرایط آزمایشگاهی بررسی و حداقل غلظت مهارکنندگی (MIC) آنها تعیین شد. روش بررسی: در این مطالعه تجربی اسانس گیاهان توسط دستگاه کلونجر و به روش تقطیر با آب استخراج گردید. ترکیبات تشکیل دهنده‌ی اسانس این گیاهان توسط کروماتوگرافی گازی تجزیه ای (GC) و گاز کروماتوگراف متصل به طیف سنجی جرمی (GC/MS) مورد شناسایی قرار گرفتند و درصد ترکیبات آنها اندازه گیری شد. برای تعیین MIC هر اسانس بر روی باکتری های مورد مطالعه از روش ریز رقت (Micro Dilution) استفاده گردید. یافته ها: نتایج نشان داد در اسانس گیاهان بومادران، گشنیز و شوید به ترتیب آلفا-پینن، -Dکارون و لینالول ترکیبات عمده را تشکیل می دهند. برای مهار رشد باکتری‏های اشیرشیا کلی و باسیلوس لیچنی فورمیس، اسانس شوید با غلظت ppm 5/312 و برای مهار رشد باکتری های باسیلوس سرئوس و سودوموناس آئروجینوزا به ترتیب اسانس های گیشنیز و بومادران با غلظت‌های ppm 1250 و ppm 5/312 موثرتر واقع شدند. نتیجه گیری: اسانس هر سه گیاه گشنیز، بومادران و شوید اثر ضد میکروبی قابل توجهی روی باکتری‏های مورد مطالعه داشتند و ممکن است بتوان از آنها به خصوص از شوید در درمان عفونت ها استفاده کرد

Weather Forecasting Error in Solar Energy Forecasting

As renewable distributed energy resources (DERs) penetrate the power grid at an accelerating speed, it is essential for operators to have accurate solar photovoltaic (PV) energy forecasting for efficient operations and planning. Generally, observed weather data are applied in the solar PV generation forecasting model while in practice the energy forecasting is based on forecasted weather data. In this paper, a study on the uncertainty in weather forecasting for the most commonly used weather variables is presented. The forecasted weather data for six days ahead is compared with the observed data and the results of analysis are quantified by statistical metrics. In addition, the most influential weather predictors in energy forecasting model are selected. The performance of historical and observed weather data errors is assessed using a solar PV generation forecasting model. Finally, a sensitivity test is performed to identify the influential weather variables whose accurate values can significantly improve the results of energy forecasting

Evaluation of knowledge and health behavior of University of Medical Sciences students about the prevention of COVID-19

Background: Coronaviruses are a large family of viruses that have symptoms ranging from the common cold to severe respiratory syndromes. Objective: The purpose of this study is to provide appropriate strategies to raise knowledge and health behavior of students of the University of Medical Sciences to prevent COVID-19. Methods: This study was conducted as a cross-sectional and descriptive study, and the online questionnaire was used by random sampling. Our sample size was 360 subjects and the statistical population was the students of the University of Medical Sciences. We used the nonparametric test (Kruskal Wallis, Mann-Whitney U) and (Chi-Square t-test) for statistical analysis. Results: The test results were statistically significant for students' health behavior (p<0.01, df -99). The knowledge of women was higher than men (F=5.32, p<0.02). Conclusion: The results show that the Ministry of Health has acted well in promoting students' knowledge and health-promoting behaviors. Therefore, it is recommended that such research be conducted in the public statistical population

Sensor - Assisted Enhancement of Cyber and Physical Resilience in Power Systems

The focus of this dissertation is on seeking ways to enhance cyber and physical resilience in power systems. The enhanced resilience is achieved via placement, networking, of modern digital sensors, and processing of their measurements. Here, cyber and physical resilience broadly refers to the ability to support uninterrupted system operation, and tolerance to random events and cyber-physical attacks. This dissertation details the development of a synchrophasor availability (SA)-constrained measurement network design to tolerate data loss/alteration, a sensor-defined power system partition algorithm to reduce computational and communication complexities in various monitoring tasks, and a transient stability assessment method to serve the system protection purpose in large lossy power systems. The SA-constrained sensor placement algorithm considers robust allocation of (additional) phasor measurement units (PMU) into a (new) PMU network in order to meet a data availability profile in the face of random communication interruptions, transmission line faults, and GPS spoofing attacks. SA at a bus is the fraction of time on average its time-synchronized current/voltage phasors are correctly present for real-time usage. The sensor-defined partition algorithm of a transmission network is applied to both real-time diagnosis of transmission circuit faults and to detection and isolation of GPS spoofed PMUs. The partitions are bordered by the measurement nodes of a PMU network. Conditions required for diagnosability and detectability are explicitly imposed on both the transmission and the measurement networks. The algorithm is applied to partitioning the IEEE 68-bus system, the IEEE 118-bus system, the Polish 3120-bus system and the PEGASE 9241-bus system. To address the challenges arising from stability assessment of large lossy power systems, a coverage-based stability assessment is pursued with focus on resolving computation and scalability issues for system protection purpose. This approach involves online tracking of each generator's electromechanical state using a local quasi-steady-state sinusoidal (QSSS) measurement model, and determining whether the state is enclosed in an offline-computed inner approximation of the post-fault region of attraction (RoA) at the time the RoA is established by a protection action. The approach to transient stability assessment is tested on a lossy 68-bus system subject to transmission faults

Knee Kinematic Improvement After Total Knee Replacement Using a Simplified Quantitative Gait Analysis Method

Objectives: The aim of this study was to extract suitable spatiotemporal and kinematic parameters to determine how Total Knee Replacement (TKR) alters patients&rsquo; knee kinematics during gait, using a rapid and simplified quantitative two-dimensional gait analysis procedure. Methods: Two-dimensional kinematic gait pattern of 10 participants were collected before and after the TKR surgery, using a 60 Hz camcorder in sagittal plane. Then, the kinematic parameters were extracted using the gait data. A student t-test was used to compare the group-average of spatiotemporal and peak kinematic characteristics in the sagittal plane. The knee condition was also evaluated using the Oxford Knee Score (OKS) Questionnaire to ensure thateach subject was placed in the right group. Results: The results showed a significant improvement in knee flexion during stance and swing phases after TKR surgery. The walking speed was increased as a result of stride length and cadence improvement, but this increment was not statistically significant. Both post-TKR and control groups showed an increment in spatiotemporal and peak kinematic characteristics between comfortable and fast walking speeds. Discussion: The objective kinematic parameters extracted from 2D gait data were able to show significant improvements of the knee joint after TKR surgery. The patients with TKR surgery were also able to improve their knee kinematics during fast walking speed equal to the control group. These results provide a good insight into the capabilities of the presented method to evaluate knee functionality before and after TKR surgery and to define a more effective rehabilitation program