bluuebunny/crossref_metadata_2025 huggingface dataset:
Resting Left Ventricular Dyssynchrony and Mechanical Reserve in Asymptomatic Normotensive Subjects with Early Type 2 Diabetes Mellitus
Authors: Mahfouz Ragab A. , Seaoud Elshaimaa A. , Elbelbesy Radwa A. , Shehata Islam E.
Published: June 2020

Background: Most diabetic patients have silent ischemia and cardiac dysfunction that is usually observed in the late phase of the disease when it becomes clinically obvious. We hypothesized that left ventricular dyssynchrony (LVdys) (or dispersion) is an early marker of myocardial involvement in asymptomatic early type 2 diabetes mellitus (T2DM) patients. Therefore, we aimed to detect early markers of myocardial dysfunction in early T2DM using LVdys and left ventricular mechanical reserve (LVMR). Methods: We examined 91 consecutive subjects with early T2DM with speckle tracking imaging to evaluate LVdys and with dobutamine stress to evaluate LVMR (defined as left ventricular mechanical reserve global longitudinal strain [LVMRGLS] ≥2%). Our patients were divided into two groups according to LVdys: group 1 with LVdys (n = 49), and group 2 without LVdys (n = 42). Results: We found that 49 (54%) subjects in our cohort had resting LVdys (standard deviation of tissue synchronization of the 12 left ventricular segments [Ts-SD-12] ≥34.2 ms). GLS and strain rate were comparable at rest between patients with and without LVdys. On the other hand, LVMR was blunted in those with LVdys (p < 0.001). We found that HbA1c, high-sensitivity C-reactive protein, and left atrial volume index were inversely correlated with LVMR. Multivariate analysis showed that LVdys was the strongest predictor (p < 0.001) of blunted LVMR. Using receiver operating characteristic curve analysis, we found that a Ts-SD-12 ≥36.5 ms was the best cutoff value to predict blunted LVMR (area under the curve = 0.89, p < 0.001). Conclusion: The LVdys (Ts-SD-12) cutoff ≥36.5 ms was the optimal value for prediction of impaired LVMR and might be an early marker of subclinical cardiac dysfunction and risk stratification of subjects with asymptomatic early T2DM with preserved left ventricular ejection fraction.
Deep Brain Stimulation Lead Implantation Using a Customized Rapidly Manufactured Stereotactic Fixture with Submillimetric Euclidean Accuracy
Authors: Ball Tyler J. , John Kevin D. , Donovan Andrew M. , Neimat Joseph S.
Published: June 2020

Background: The microTargetingTM MicrotableTM Platform is a novel stereotactic system that can be more rapidly fabricated than currently available 3D-printed alternatives. We present the first case series of patients who underwent deep brain stimulation (DBS) surgery guided by this platform and demonstrate its in vivo accuracy. Methods: Ten patients underwent DBS at a single institution by the senior author and 15 leads were placed. The mean age was 69.1 years; four were female. The ventralis intermedius nucleus was targeted for patients with essential tremor and the subthalamic nucleus was targeted for patients with Parkinson’s disease. Results: Nine DBS leads in 6 patients were appropriately imaged to enable measurement of accuracy. The mean Euclidean electrode placement error (EPE) was 0.97 ± 0.37 mm, and the mean radial error was 0.80 ± 0.41 mm (n = 9). In the subset of CT scans performed greater than 1 month postoperatively (n = 3), the mean Euclidean EPE was 0.75 ± 0.17 mm and the mean radial error was 0.69 ± 0.17 mm. There were no surgical complications. Conclusion: The MicrotableTM platform is capable of submillimetric accuracy in patients undergoing stereotactic surgery. It has achieved clinical efficacy in our patients without surgical complications and has demonstrated the potential for superior accuracy compared to both traditional stereotactic frames and other common frameless systems.
Groove Pancreatitis Associated with Transient Liver Injury Mimicking Ampullary Neoplasm
Authors: Ali Elrazi Awadelkarim Hamid , Mahfouz  Ahmed Emad  , Jones  Akhnuwkh , Abdelmola Abdelatif , Yassin Mohamed A.
Published: June 2020

Groove pancreatitis is an unusual form of pancreatitis characterized by fibrous inflammation and pseudo-tumor in the area around the head of the pancreas. The underlying etiology is unknown but is strongly linked to alcohol abuse. We report a 52-year-old male smoker with hypertension, asthma, and alcohol abuse who was admitted with severe epigastric pain radiating to the back. He was found to have acute pancreatitis. A computed tomography scan of the abdomen showed a mass lesion in the peri-ampullary region. MRI of the abdomen revealed dilated common bile duct and duodenal mass and features suggestive of groove pancreatitis. During the hospital stay, bilirubin and liver enzymes started to rise and then decreased gradually to the previous normal range. The secondary workup for liver disease was unremarkable. The patient improved and was discharged. Six-month follow-up showed regression of the duodenal lesion and reduction in the common bile duct dilatation. Excluding malignancy remains the main challenge in managing groove pancreatitis, and a conservative approach is more reasonable in cases with a typical profile.
Yersinia Enterocolitis May Mimic Appendicitis: 12 Years of Experience in a Single Tertiary Center
Authors: Fernandes Sara , Vasconcelos-Castro Sofia , Teixeira Cláudia , Soares-Oliveira Miguel
Published: June 2020

Introduction: Yersinia enterocolitica infection is a zoonotic disease that varies from self-limited gastroenteritis to more severe forms. Its propensity to affect the terminal ileum and to spread to regional lymph nodes explains the potential misdiagnosis with appendicitis. Methods: We reviewed the Y. enterocoliticainfection cases in a pediatric population for the last 12 years. Results: There were 11 cases of Y. enterocolitica infection in the selected period. Four patients had a suspected surgical diagnosis: 1 intussusception, 3 acute appendicitis. Patients who presented with appendicitis-like features were older, whereas younger children most commonly presented with diarrhea and fever. Ultrasound and abdominal computed tomography (CT) were performed in appendicitis-like patients and ruled out appendicitis in 2 of the 3 cases. The only patient submitted to surgery had abnormal CT findings and an important risk factor for this infection that was not recognized at presentation. Conclusion: This condition should be considered in patients with known risk factors (such as iron overload) and with the right epidemiological setting when presenting with abdominal symptoms. The suspicion of this diagnosis in these particular cases might obviate unnecessary surgical interventions.
Advances in Pathogenesis of Idiopathic Membranous Nephropathy
Authors: Xu Zhifeng , Chen Lu , Xiang Huiling , Zhang Chun , Xiong Jing
Published: June 2020

Background: Membranous nephropathy (MN), a major cause of nephrotic syndrome, has attracted people’s attention in recent years for its growing prevalence. It is the second or third leading cause of ESRD in patients with primary glomerulonephritis and is the leading glomerulopathy that recurs after kidney transplantation. Summary: MN can be classified as idiopathic membranous nephropathy (IMN) and secondary MN. The discovery of the M-type phospholipase A2 receptor (PLA2R) and thrombospondin type-1 domain-containing 7A (THSD7A) provides the new diagnostic methods and treatment strategies for IMN on the molecular level. The study on single nucleotide polymorphism of IMN genes, such as the single M-type phospholipase A2 receptor 1 (PLA2R1) gene and human leukocyte antigen (HLA) gene, explains the pathogenesis of the disease from the perspective of genetics and conforms to the trend of the era of precision medicine. Key Messages: This review focuses on advances in the pathogenesis of IMN, including molecular and genetic pathogenesis, as well as discussing the diagnostic and treatment guiding value brought by these new discoveries.
Optimal Systemic Treatment for Early Triple-Negative Breast Cancer
Authors: Furlanetto Jenny , Loibl Sibylle
Published: June 2020

Background: Approximately 10–15% of all breast tumors are triple-negative breast cancer (TNBC). TNBC have a higher risk of relapse and distant metastases compared to other subtypes. The optimal systemic management of TNBC according to national and international guidelines is discussed herein. Summary: Anthracycline/taxane-based chemotherapy for patients with TNBC either in the neoadjuvant (NACT) or the adjuvant setting is considered standard of care. Exceptions are small tumors and a low-risk histology, in which chemotherapy can be spared. Dose-dense therapy is more effective in preventing recurrence and increasing survival. The use of nab-paclitaxel instead of a solvent-based taxane can lead to higher pathological complete response (pCR) rates and better outcomes. Platinum agents are effective in increasing pCR when added to anthracycline/taxane-based chemotherapy at the cost of increased toxicity. Long-term outcome data are lacking. In patients without a pCR, capecitabine leads to improved outcomes. Key Messages: The standard treatment approach of TNBC is anthracycline/taxane-based chemotherapy, preferably within the NACT setting. Dose-dense schedules as well as platinum should be considered in the NACT setting. For patients without a pCR, capecitabine is an option to improve the outcome. The role of nab-paclitaxel is under debate. In case of immunogenic tumors, checkpoint inhibitors are promising new agents that merit further investigation.
A Multicenter Study of the Prevalence of Dry Eye Disease in Chinese Refractive Surgery Candidates
Authors: Li Meiyan , Zeng Li , Mi Shengjian , Li Ying , Liu Zhirong , Yu Keming , Hu Qi , Li Haiyan , Ma Daijin , Zhou Yuehua , Wang Jibing , Guo Xiaomei , Fang Xuejun , Bai Ji , Choi Joanne , Zhou Xingtao
Published: June 2020

Objective: The aim of this study was to determine the prevalence of preoperative dry eye disease and evaluate tear film function in refractive surgery candidates in China. Methods: In this prospective noninterventional cross-sectional study, refractive surgical candidates from 13 preselected eye hospitals in China were recruited from July 2015 to February 2016. Patient histories, subjective symptoms, tear film breakup time (TBUT), ocular surface fluorescein staining, and Schirmer I tests (SIT), were assessed to conduct subgroup analysis. Results: A total of 1,849 patients were recruited, 41.4% were diagnosed with dry eye disease (766/1,849) and 44.9% (830/1,849) of subjects had a positive history of contact lens (CL) wear. The overall mean TBUT and SIT values were 7.3 ± 3.7 s and 15.2 ± 8.8 mm, respectively. The total prevalence of ocular surface fluorescein staining was 23.46% (422/1,849); 44.62% of patients had TBUT <5 s and 23.20% of patients had SIT <5 mm. CL wearers were observed to have a higher prevalence of dry eye than non-CL wearers (54.1 vs. 35.2%, OR = 2.17, 95% CI: 1.77–2.65). Conclusions: In this study, the most common abnormal finding in dry eye disease was tear film instability. A high proportion of refractive surgery candidates have preexisting dry eye disease and a history of CL wear prior to surgery. Careful attention should be given to the evaluation of preoperative dry eye in refractive surgery candidates.
Energy-economic-environmental analysis of solar drying system: a review
Authors: Desa Wan Nurlaila Yusra Mat , Fudholi Ahmad , Yaakob Zahira
Published: June 2020

Solar drying is an emerging technology to preserve wide range of products from agriculture to animal-based products. The application of solar dryers, however must be evaluated to determine its benefit and effectiveness. In the evaluation of solar dryer performance, three criteria which are most important to look at are thermal performance, economic cost and environmental implications. Therefore, this paper attempts to review the thermoeconomic analysis and environmental evaluation on various solar drying system. Performance equations in energy–economic–environment analyses for solar drying syistems evaluation are presented. The CO2 emission, carbon mitigation, and earned carbon credit of various solar drying syistem are also presented.
Fault tolerance of asymmetrical six-phase induction machine during single open circuit fault to three open circuit faults using GUI
Authors: Rahman Ungku Mohamed Ismail Adrian Ungku Abdul , Munim Wan Noraishah Wan Abdul , Che Hang Seng , Tousizadeh Mahdi , Muhammad Khairul Safuan
Published: June 2020

The fault tolerance of multiphase drive is favourable in the industry for its reliability and safety reasons. However, from the educational point of view, the post-fault capability of six-phase machine is still unclear. This paper presents the fault tolerance of asymmetrical six-phase induction machine (A6-IM) under one to three open-circuit faults using Graphical User Interface (GUI). In this study, the capability of A6-IM has been interpreted through a simple and user-friendly GUI helping students to have a better understanding on the current limits of A6-IM. The optimization of post-fault current references is based on maximum torque (MT) and minimum loss (ML). This work provides GUI highlighting the post-fault derating of A6-IM with single isolated neutral (1N) in two different modes namely MT and ML for educational purposes.
The effect of static and dynamic eccentricities on the performance of flux reversal permanent magnet machine
Authors: Shuraiji Ahlam Luaibi
Published: June 2020

This study investigates the effect of static and dynamic eccentricities on the performances of flux reversal permanent magnet (FRPM) machine with even rotor pole number, i.e. FRPM machine with 12/10 stator/rotor combination. No-load and load performances of the machine are investigated under three rotor operating conditions including centricity, static eccentricity and dynamic eccentricity. The investigation has been carried out using 2D-FEA. It has been revealed that the 12/10 FRPM machine under normal operating condition has no unbalanced magnetic force, due to the even pole number of the rotor. On the other hand, such undesirable feature would be presented in the 12/10 FRPM machine as a result of the existing of static and dynamic eccentricities.  Both static and dynamic eccentric machines exhibit unbalanced three-phase flux linkage as well as back-EMF.  Moreover, three operating conditions of the investigated machine have the same fundamental cogging torque harmonic. However, low order harmonics are existed in the static and dynamic centric machines and are not found in the centric machine. Furthermore, about 16% less torque ripple delivered by the centric machine compared with both static and dynamic counterparts.
Life-cycle assessment of residential-scale grid-connected photovoltaic system in Malaysia based on monocrystalline silicon modules
Authors: Nordin Atiqah Hamizah Mohd , Sulaiman Shahril Irwan , Shaari Sulaiman , Mustapa Rijalul Fahmi
Published: June 2020

Even though PV systems have been promoted as a green form of electrification, such systems are still contributing to environmental impacts after considering life-cycle impact during material extraction, manufacturing processes of its components, installation, operation, and maintenance. This paper presents a life-cycle assessment to quantify the environmental impact of residential-scale grid-connected PV systems in Malaysia using monocrystalline silicon PV module. LCA had been carried out by using OpenLCA 1.8 software, Ecoinvent 3.5 database, and impact assessment method of IMPACT2002+ and CED. The influence of varying system capacity from 3 to 12 kWp, system lifetime of 21, 25 and 30 years, and solar irradiation of 1560.8, 1651.8, & 1935.5 kWh/m2/yr, were investigated. The results revealed that the greenhouse gas emissions rate, cumulative energy demand, and energy payback time of residential-scale grid-connected PV systems in Malaysia ranged from 37.97 to 67.26 g CO2-eq/kWh, 4387.10 to 4699.99 MJ/m2, and 6.37 to 7.90 years, respectively. This study also evaluated indicators of energy return on investment. The overall finding implies that the installation of residential-scale grid-connected PV systems in Malaysia offers significant potential for GHG emissions reduction in the country.
Modeling and simulation of SEPIC controlled converter using PID controller
Authors: Khather Salam Ibrahim , Ibrahim Muhammed A.
Published: June 2020

The topology of SEPIC "Single-ended primary inductance converter" is considered as a suitable option for automotive power system where the value of the output voltage should be ranging between the low and high values of the input value of voltage. The main feature of the DC-DC converter is the stability of output voltage. This paper shows the SEPIC converter employing PID converter to be used in industrial applications. A SEPIC DC-DC converter can manage either step-down mode or step-up mode. The benefit of using this circuit is to supply a stable and controlled output voltage no matter how much the input voltage is. The simulated behaviors of the uncontrolled and controlled SEPIC converter are presented in this paper. The PID controller based on bat algorithm (BA) optimization method is used for searching of the best Proportional–Integral-Derivative (PID) gains. The solution has given very good performance and whatever the output reference voltage variation and load disturbance of the system.
Jammer against eavesdropper in half-duplex energy harvesting cooperative relaying networks: secrecy outage probability analysis
Authors: Tin Phu Tran , Ha Duy-Hung , Tran Minh , Trang Tran Thanh
Published: June 2020

In this paper, we have investigated the Half-Duplex (HD) Energy Harvesting (EH) Cooperative Relaying Networks with one source node, one destination node, one intermediate relay and in the presence of the Jammer Against Eavesdropper. We have analyzed the system performance in terms of the integral form expression of secrecy outage probability. In addition, we have investigated the effect of source rate, time switching factor, energy coefficient, and the ratio Ps/N0 on the system performance. Finally, all the mathematical, analytical expressions are verified by Monte Carlo simulation, and the analytical results match well with the simulation ones to convince the correctness of the analytical expression.
Enhancement of cascaded multi-level VSC STATCOM performance using ANN in the presence of faults
Authors: Almelian Mohamad M , Mohd Izzeldin I , Ahmad Abu Zaharin , A Omran Mohamed , Salem Mohamed , Jusoh Awang , Sutikno Tole
Published: June 2020

A system can be disturbed in terms of stability when connected to a number of loads at the distribution ends or when subjected to faults. To reverse such systems to a stable state, FACTS devices such as static synchronous compensator (STATCOM) are used. In this paper, a cascaded multi-level voltage source converter (VSC) STATCOM was designed and implemented with a novel space vector pulse width modulation (SVPWM) scheme. Artificial neural network (ANN) controller was used instead of instead of Proportional-Integral (PI) controller in the proposed scheme to improve the response time (RT) and performance of STATCOM in terms of power factor (PF) and voltage amplitude during periods of voltage sag. During the implementation, two fault sources (single-line-to-ground (SLG) and line-to- line (LL) faults) were used to create voltage sag. STATCOM was subjected to performance evaluation in the presence of these disturbances via MATLAB simulation in IEEE 3-bus system. The outcome of the simulation studies showed the ANN controller to perform better than PI as it was able to rapidly recover voltage value (<1 cycle) with unity PF.
Design and performance analysis of stand-alone PV system at Al-Nahrain University, Baghdad, Iraq
Authors: Mahmood Anas Lateef , Shakir Amina Mahmood , Numan Bahaa Abdulkhaliq
Published: June 2020

The use of the stand-alone PV systems for electric power generation is important to meet the needs of electric power, especially in countries that have major problems in the generation and continuity of electricity such as Iraq. The aim of this research is to design and simulate a stand-alone PV system installed on the roof of the parking garage in the College of Engineering at Al-Nahrain University for the purpose of using the electrical energy generated by this system to meet the energy demand of the daily light for the parking garage and engineering laboratories buildings beside it.
 The main factor in the design was the total area of the roof of the parking garage. The Pvsyst6 program is used to simulate the suggested PV system and to determine the effect of partial shading which caused by the trees surrounding the garage on the available generated power of the system. A comparison was made between four types of solar panels to see the suitability of these types to the weather conditions in Iraq, in addition to the impact of the shadows surrounding the garage. These types of solar panels were (CIS SL2-145, CdTe F-4112-3, Poly JAP6-60-260, and Mono JAM6-60-260), CdTe type showed better performance compared to other types in terms of available energy generated because it has small losses due to temperature and shadows. It was found that the best tilt angle of the solar panels in the case of shadows is 19o to the south. Finally, the financial analysis was made to see the economic feasibility of this PV system and it is found that the PV system that uses CdTe panels has the smallest kWh unit price (0.236 $/kWh) as compared with the other three types.
Improved MPPT controls for a standalone PV/wind/battery hybrid energy system
Authors: Zebraoui Otmane , Bouzi Mostafa
Published: June 2020

In this paper, we present the modeling, optimization and control of a standalone hybrid energy system combining the photovoltaic and wind renewable energy sources to supply a dc electrical load, with storage batteries as a backup source. With the aim of improving the energy performance of the proposed system, we developed an MPPT controller based on new hybrid and robust approaches to evolve the power quality produced by both PV and Wind subsystems. For the PV subsystem, the proposed approach is based on the methods perturb and observe (P&O), sliding mode control (SMC) and fuzzy logic control (FLC). For the Wind subsystem, the proposed technique is based on the hill climbing search algorithm (HCS) and the fuzzy logic control. Also, to evaluate the efficiency of the developed controls and to analyze the behavior of each system during their maximum power point tracking, a comparison study was carried out with conventional techniques and the simulations are performed under varying weather conditions. The simulations results show the good performance of the proposed MPPT controls compared to other methods with better response time, a higher optimal power point and negligible oscillations.
Adaptive dynamic programing based optimal control for a robot manipulator
Authors: Nam Dao Phuong , Hong Quang Nguyen , Phuong Nam Tran , Hai Yen Tran Thi
Published: June 2020

In this paper, the optimal control problem of a nonlinear robot manipulator in absence of holonomic constraint force based on the point of view of adaptive dynamic programming (ADP) is presented. To begin with, the manipulator was intervened by exact linearization. Then the framework of ADP and Robust Integral of the Sign of the Error (RISE) was developed. The ADP algorithm employs Neural Network technique to tune simultaneously the actor-critic network to approximate the control policy and the cost function, respectively. The convergence of weight as well as position tracking control problem was considered by theoretical analysis. Finally, the numerical example is considered to illustrate the effectiveness of proposed control design. 
Phase to phase fault detection of 3-phase induction motor using FRA technique
Authors: Alawady A. A. , Yousof M. F. M. , Azis N. , Talib M. A.
Published: June 2020

The purpose for preparing this paper is to innovate a new method to detection and diagnosis the three-phase induction motor electrical failures, especially the failures that occur in Stator winding. Stator winding breakdown largely contributes to induction motor failures. To understand internal fault in induction motors winding, four cases studies of different three-phase induction motors (TPIM) were analysed according to two conditions: normal winding condition and windings shorted between two phases. In this paper, the measurement of frequency response analysis (FRA) on the stator winding with inter-phase short is presented. Additionally, Frequency Response Analysis (FRA) interpretation technique classify and quantify the fault is also proposed. For interpretation of the FRA, a statistical indicator, which is NCEPRI algorithm is used for comparison the measured responses.
A study of sensorless vector control of IM using neural network luenberger observer
Authors: Belbekri Tahar , Bouchiba Bousmaha , Bousserhane Ismail khalil , Becheri Houcine
Published: June 2020

After the development of electronic components, the elimination of the sensors has become a necessary subject to get good results in the field of speed control, because of the price of the sensors, the strenuous choice of its position and the disturbance of measurement which affects the robustness of control. The luenberger observer showed to be one of the most excellent methods suggested by the researchers; this is due to the best performance, it offers in terms of stability, reliability and less counting effort. In this article, a study of luenberger observer based on neural network-based was discussed. This artificial intelligence method makes it possible to decrease the error of estimated speed for IRFOC control of the induction motor. Simulation results are obtained to show the robustness and stability of the system.
Simultaneous placement of FACTS devices using cuckoo search algorithm
Authors: Patil Basanagouda N. , Karajgi S. B.
Published: June 2020

The power system deregulation requires thechange in reactive power compensation in the power system. The optimal placement of FACTs (Flexi ble AC transmission system) devices is mandatory to recalculate the reactive power compensation in deregulation case. The FACTs devices generally used in series and shunt conections. Here the various facts devices connected in series & shunt combination simultaneously. The optimal placement and sizing of the devices are done in this paper by formulating the objective function with minimization of cost of the generation and minimizing the cost of Facts devices. MALAB is used for writing the code. IEEE 14 bus system is used to here for testing the system. Placing the FACTs separately and simultaneously are studied in case study. Cuckoo search algorithm is used to identify the solution to the optimization problem.
Design and implementation of an optimized multilevel power inverter structure based on C MEX and PSPICE
Authors: Setti Mohammed , Cherkaoui Mohamed
Published: June 2020

In this paper, both symmetric and asymmetric operations for an optimized cascaded multilevel power inverter (MLI) are thoroughly examined. While symmetric configurations are more suitable for AC drives due to their equal power sharing among the various levels, the asymmetric topologies fulfill the higher number of power source combinations under the same power semiconductor switch count. Additionally, particular attention was put on the design of this optimized topology in terms of both reliability and power efficiency by managing redundant states and minimizing the number of power switch commutations. Furthermore, a fundamental switching frequency modulation (FSFM) is thoroughly described in C MEX programming language and then the resulting gating signals are fed into the power circuit designed with PSPICE. By applying this co-simulation approach, the control design task is greatly simplified while achieving advanced analyses with more realistic electronic devices.
Wireless power transfer system design for electric vehicle dynamic charging application
Authors: Diep Nguyen Thi , Trung Nguyen Kien , Minh Tran Trong
Published: June 2020

This paper proposes and demonstrates a wireless power transfer system design for electric vehicle dynamic charging applications. The dynamic wireless charging (DWC) lane is designed for modularly. Each module has three shorttrack transmitter coils that are placed closely together and connected to a single inverter to reduce the number of inverters. The magnetic coupler design is analyzed and optimized by finite element analysis (FEA) to reduce the output power variation during dynamic charging. The LCC compensation circuit is designed according to the optimal load value to obtain maximum efficiency. The SIC devices are used to improve the efficiency of the high-frequency resonant inverter. A 1.5 kW dynamic charging system prototype is constructed. Experimental results show that the output power variation of 9.5% and the average efficiency of 89.5% are obtained in the moving condition.
Voltage profile and power quality improvement in photovoltaic farms integrated medium voltage grid using dynamic voltage restorer
Authors: Benali Abdelkrim , Khiat Mounir , Denai Mouloud
Published: June 2020

In this paper, we have presented a simulation study to analyze the power quality of three phases medium voltage grid connected with distribution generation (DG) such as photovoltaic (PV) farms and its control schemes. The system uses two-stage energy conversion topology composed of a DC to DC boost converter for the extraction of maximum power available from the solar PV system based on incremental inductance technique and a three-level voltage source inverter (VSI) to connect PV farm to the power grid. To maintain the grid voltage and frequency within tolerance following disturbances such as voltage swells and sags, a fuzzy logic-based Dynamic Voltage Restorer is proposed. The role of the DVR is to protect critical loads from disturbances coming from the network. Different fault conditions scenarios are tested and the results such as voltage stability, real and reactive powers, current and power factor at the point of common coupling (PCC) are compared with and without the DVR system.
A maximum power point tracking based on levy flight optimization
Authors: Charin C. , Ishak Dahaman , Mohd Zainuri Muhammad Ammirrul Atiqi
Published: June 2020

This paper proposes a Levy flight global maximum power point tracking for solar photovoltaic (PV) system under partial shading conditions. The proposed method comes with merits such as simplicity, fast response and free of oscillation. This algorithm uses random search over the exploration space and compares the previous and current states to obtain the best solution. For evaluation and comparative analysis, performance of the proposed method is also measured against Perturb and Observe (P&O) and Particle Swarm Optimization (PSO). All three algorithms are simulated in MATLAB/Simulink environment. Simulation results are satisfactory over the conducted tests under uniform and non-uniform irradiance. The proposed algorithm is able to track global maximum power point (GMPP) under partial shading conditions with fast tracking time and zero ripple at steady-state.
Theoretical and experimental analysis of photovoltaic module characteristics under different partial shading conditions
Authors: Numan Ali Hussein , Dawood Zahraa Salman , Hussein Hashim A.
Published: June 2020

Recently, the renewable energy resources have gained more attention in the electricity sector as promising technology to tackle the depletion in the traditional energy resources. Solar energy grows rapidly due to its vast applications. The performance of Photovoltaic (PV) system is affected by partial shading that results from building, clouds, and fallen leaves. This paper investigates theoretically and experimentally the impacts of various cases of partial shading; such as vertical string, horizontal string, and single cell at environmental conditions on the current-voltage and power-voltage characteristics of 88 W PV panel. In addition, diagonal shading with multi steps is considered in the analysis. The experiments are conducted with considering various parameters; such as shading position and ratio to validate the simulated results. The results show that at 100% shading condition, the maximum power drops by 99.36 %, 43.7%, and 41.15% for horizontal, cellular and vertical shading at the same solar radiation level comparing with their initial state value. Horizontal string shaded has the highest negative impact on the power and efficiency among other types of shadings. The comparison between the theoretical and experimental results reveals considerable agreement between the theoretical and experimental results.
Impact of field roughness and power losses, turbulence intensity on electricity production for an onshore wind farm
Authors: Dragusha Bedri , Hoxha Bukurije
Published: June 2020

When designing a power generation project from a different source, and in our case study, wind, when calculating the annual energy produced, it is necessary to define and calculate the losses incurred in the system.  The main cause of losses in a wind park is due to the oscillations caused by the turbulence of the air around the turbine because of roughness of terrain. The paper describes two methods of estimating turbulence intensity: one based on the mean and standard deviation (SD) of wind speed from the nacelle anemometer, the other from mean power output and its SD. These analyses are very important for understanding the fatigue and mechanical stress on the wind turbines. Then significance of the site ruggedness index (RIX) and the associated performance indicator (ΔRIX) are confirmed for terrain and the consequences of applying WAsP outside its operating envelope are quantified.
Voltage regulation of an asynchronous wind turbine using STATCOM and a control strategy based on a combination of single input fuzzy logic regulator and sliding mode controllers
Authors: Mokhtari Mohammed , Zouggar Smail , M’Sirdi Nacer K. , Elhafyani Mohamed Larbi
Published: June 2020

In the literature, it is well known that reactive power management is the greatest challenge in wind turbine based on a three-phase self-excited induction generator. Any variation of wind speed or load causes a variation on the needed reactive power and thus a voltage fluctuation. Flexible AC transmission device such as STATCOM become then a necessity to prevent voltage instability and hence voltage collapse at the point of common coupling. This paper proposes so a new control strategy for voltage regulation of an asynchronous wind turbine based on a combination of a single input fuzzy logic regulator and a sliding mode controller. Compared to the classical control strategy with PI regulators, the performance of the proposed compensator has been significantly improved when it is controlled by the new approach and the system have shown more robustness and stability regarding external disturbances. The present document traits so the modelling of the power system, the simulation results and the controller’s scheme and design.
Voltage regulation and power loss reduction by integration of SVC in distribution networks via PSSE
Authors: Saleh Ba-swaimi , Yin Lee Jun , Verayiah Renuga
Published: June 2020

Voltage stability is necessary in order to maintain the health of the grid system. In recent years, the load demand is increasing from time-to-time which compromised the stability of the system. On that purpose, several methods on enhancing the voltage stability of the system was introduced such as the transformer tap and FACTS devices. In a general overview, this study is to propose a several power compensation techniques on the base case of an IEEE-33 bus whereby power flow analysis using Netwon- Raphson in PSS/E software is performed. Afterwards, distributed generation (DG) and Static VAR Compensator (SVC) will be implemented within the distribution network to compensate the voltage instability losses based on the weakest index from the bus system. From both the cases which is proposed earlier, a comparison study is conducted on the performance on both DG and SVC within the proposed network.
Parameters observation of restoration capacity of industrial lead acid battery using high current pulses
Authors: Ibrahim N. S. M. , Ponniran Asmarashid , Rahman R. A. , Martin M. P. , Yassin A. , Eahambram A. , Aziz M. H.
Published: June 2020

Batteries play an essential role on most of the electrical equipment and electrical engineering tools. However, one of the drawbacks of lead acid batteries is PbSO4 accumulates on the battery plates, which significantly cause deterioration. Therefore, this study discusses the discharge capacity performance evaluation of the industrial lead acid battery. The selective method to improve the discharge capacity is using high current pulses method. This method is performed to restore the capacity of lead acid batteries that use a maximum direct current (DC) of up to 500 A produces instantaneous heat from 27°C to 48°C to dissolve the PbSO4 on the plates. This study uses an 840 Ah, 36 V flooded lead acid batteries for a forklift for the evaluation test. Besides, this paper explores the behavior of critical formation parameters, such as the discharge capacity of the cells. From the experimental results, it can be concluded that the discharge capacity of the flooded lead acid battery can be increase by using high current pulses method. The comparative findings for the overall percentage of discharge capacity of the batteries improved from 68% to 99% after the restoration capacity.
Reduction of single DC bus capacitance in photovoltaic cascaded multilevel converter
Authors: Hassan Turki Kahawish
Published: June 2020

This paper presented single DC bus single phase seven level cascaded H-bridge (CHB) inverter for multi-panel photovoltaic grid-connected applications. A single DC bus supplying flyback converters to produce DC link voltages for CHB cells is suggested. A balanced operation of CHB inverter cells is obtained irrespective to power unbalance occurred by individual maximum power point tracking boost converter of photovoltaic (PV) panels due to the non-uniform irradiation and partial shading. A DC bus voltage control system with addition of estimated DC bus ripple voltage to the reference is proposed to eliminate the second order harmonic contained in the feedback voltage of DC bus enabling to design high bandwidth of DC voltage control loop. This produces fast dynamic response, low total harmonic distortion (THD) of grid current and smaller DC bus capacitance. Mathematical modeling of bus voltage control system is presented. PSIM simulation program is used and the simulation results are obtained to validate the proposed control system.
Two fossil thrips from Ethiopian amber (Thysanoptera) with description of Merothrips aithiopicus sp. n. (Thysanoptera: Merothripidae)
Authors: ULITZKA MANFRED R.
Published: June 2020

Amber has rarely been found in Africa and only a few samples with fossil inclusions are known (Kiefert et al. 2015). The most important fossiliferous find was reported from an outcrop at the north-western Plateau of Ethiopia a decade ago, revealing diverse inclusions of arthropods, plant remains, fungi and microorganisms (Schmidt et al. 2010). Initially, this amber was classified as originating from the mid-Cretaceous. Later studies, however, have raised questions about this determination and indicated a much younger age: Cenozoic, likely Miocene (Coty et al. 2016, Perrichot et al. 2016, Perrichot et al. 2018). The contradictory—and rather controversial discussed—new dating was based on spectroscopic analyses, revised palynological data and more comprehensive palaeoentomological results showing that insect fossils mostly belong to extant families and genera. In total, Schmidt et al. (2010) reported 22 insects from eight identified orders including two specimens of Thysanoptera: “an undetermined, wingless thrips“ (obviously a larva) and a female associated with Merothripidae. A more detailed analysis of these specimens is the objective of the present study; regarding the larva, only a rough classification and description is given, as fossil larvae cannot be definitely associated with adult specimens.
Revision of the genus Minagrion Santos, 1965 (Odonata: Coenagrionidae)
Authors: VILELA DIOGO SILVA , ANJOS-SANTOS DANIELLE , KOROIVA RICARDO , CORDERO-RIVERA ADOLFO , GUILLERMO-FERREIRA RHAINER
Published: June 2020

Endemic to Brazil, the genus Minagrion Santos, 1965 is revised for the first time. The genus contains five species, and here we establish diagnostic characters, keys and drawings for both sexes. Furthermore, we propose the synonymy of M. franciscoi Machado & Bedê, 2015 new syn. with M. caldense Santos, 1965.
A rare new species of Leptohyphes Eaton (Ephemeroptera: Leptohyphidae) from the Lost World
Authors: MOLINERI CARLOS , DERKA TOMÁŠ
Published: June 2020

A new species of Leptohyphes Eaton (Ephemerotera: Leptohyphidae) is described, diagnosed and illustrated from nymphs collected in the Pantepui region in Southeastern Venezuela. Leptohyphes kukenan sp. nov. is similar to Leptohyphes populus Allen because they share a unique character for the genus: male compound eyes are divided. Other unique characters for the new species include a plesiomorphic gill structure, with imbricated ventral lamellae, and paired subapical denticles on tarsal claw. The new species show a unique combination of characters that distinguish it from L. populus and all other species of Leptohyphes: fore and hind margin of femora with spines on strong elevated sockets, part of body and legs covered by small pale spots, tarsal claws with 4–5 marginal denticles and a subapical pair of submarginal denticles, pronotum with large rounded lateral projection, hind wing pads absent in female, gill formula 8/7/7/4/1, operculate gill with imbricated ventral lobes, and gill V without ventral extension on dorsal lamella.
Preparation of Silver Sulfadiazine Loaded Pectin-Zinc Nanocomposites for Improvement of Antioxidant, Antibacterial and Care Cutaneous Wound Care During the Perioperative Period
Authors: Chen Linjing , Wang Fangfang , Luan Tao , Jiang Shuhong , Yu Feifei , Wang Ping
Published: June 2020

Medicinal care for cutaneous wound becomes difficult due to the emergence of antibiotic resistant bacteria. The development of a new cost-effective drug based on silver sulfadiazine loaded with pectin-zinc nanocomposites offers better therapeutics in wound healing besides its role in
enhancing antioxidant and antibacterial activities. In this study, silver sulfadiazine loaded with pectin-zinc nanocomposites (AgSD-PC-Zn) was produced and its antioxidant and antimicrobial properties were tested against wound infection causing bacterial pathogens (S. aureus and E.
coli). The synthesized AgSD-PC-Zn composite was biophysically characterized. TEM analysis confirmed the spherical shape of NPs. AgSD-PC-Zn composite exhibited a greater antibacterial effect against S. aureus and E. coli. The number of dead bacterial cells was higher after
exposure to AgSD-PC-Zn composite. Furthermore, in vitro antioxidant enzyme activities (DPPH and H2O2) were increased with AgSDPC-Zn composite. A rapid healing of the skin wounds in mouse was noticed with AgSD-PC-Zn composite treatment. This study concludes that
the newly formed AgSD-PC-Zn composite will act as a strong antimicrobial and antioxidant agents for treating skin wound infection.
Nerve Growth Factors Promotes Osteogenic Differentiation Through TGF-β and BMP-9 Signaling Pathways in Bone Mesenchymal Stem Cells
Authors: Wang Fei , Yuan Kun , Zhou Xiaogang , Xu Dawei , Sun Yuyu , Chen Feihu , Wang Peiji
Published: June 2020

Bone mesenchymal stem cells (BMSCs) are related to fracture healing. In this paper, we study the effect of Nerve growth factors (NGF) on osteogenic differentiation of BMSCs and related mechanisms. The results indicated that NGF has a dose-dependent promotion effect on osteogenic differentiation
of BMSCs, ALP activity, and protein expression of OPN, Osterix, Runx2, COL1A1. Further investigation showed that NGF enhanced the expression of TGF-β and BMP9, and increased phosphorylation of Smad and p38 MAPK. Moreover, block of BMP and TGF-β pathway reduced the promoted
effect of NGF on osteogenic differentiation. The data revealed that NGF increased osteogenic differentiation through increased phosphorylation of Smad and MAPK p38 by regulating TGF-β and BMP pathway in BMSCs. Thus, NGF may be used in bone growth and fracture healing by improving
osteogenic differentiation of BMSCs.
microRNA184 Reverses Cisplatin Resistance in Human Ovarian Cancer Cells by Regulating the Phosphatidylinositol-3-Kinase (PI3K)/Protein Kinase B (AKT) Signaling Pathway
Authors: Liu Ping , Wen Jie , Zhao Nannan
Published: June 2020

Ovarian cancer is prone to drug resistance, resulting in poor prognosis. microRNA184 plays a role in many diseases such as tumor and inflammation, but whether microRNA184 regulates ovarian cancer cisplatin resistance is unknown. The ovarian cancer SKOV3 cell line and cisplatin-resistant
strain cell SKOV3/DDP were cultured and microRNA184 expression was analyzed by Real time PCR. Transfection of microRNA184 siRNA into SKOV3/DDP under ly294002 (PI3K/AKT inhibitor) treatment followed by analysis of cell proliferation by MTT assay, Caspase 3 activity, cell migration by cell scratch
assay, levels of Bax and Bcl-2 by Real time PCR and PI3K/AKT signaling by Western blot. microRNA184 expression was significantly increased in SKOV3/DDP cells compared to SKOV3 cells (P < 0.05). microRNA184 siRNA can significantly down-regulate microRNA184 expression in SKOV3/DDP,
inhibit cell proliferation, increase Caspase 3 activity, inhibit cell migration, increase Bax expression, decrease Bcl-2 and decrease pAKT expression (P < 0.05). Addition of ly294002 further significantly promoted the above changes (P < 0.05). Targeting microRNA184 can
inhibit SKOV3/DDP cell apoptosis by inhibiting PI3K/AKT signaling pathway, decrease tumor cell proliferation and migration, and inhibit the occurrence and development of cisplatin-resistant ovarian cancer.
MiR-203 Mimic Down-Regulates Baculoviral IAP Repeat Containing 5 Expression and Affects Proliferation and Apoptosis of Gastric Cancer Cells
Authors: Xu Yanhua , Peng Pailan , Zhou Qiuyuan
Published: June 2020

Human baculovirus IAP repeats containing protein 5 (BIRC5) is the most inhibitor of cell apoptosis. Abnormal miR-203 level is associated with the pathogenesis of gastric cancer. Bioinformatics analysis revealed a relationship between miR-203 and BIRC5. Our study assessed miR-203’s
role in gastric cancer cells. Tumor tissues and adjacent tissues were collected. miR-203 and BIRC5 mRNA expression in SGC7901 and MKN45 cells was detected by real-time PCR. SGC7901 cells were divided into miR-NC group and miR-203 mimic group followed by analysis of cell proliferation by EdU
staining. Compared to adjacent tissues, miR-203 level was decreased and BIRC5 was increased. There was a targeted relationship between miR-203 and BIRC5. Compared with RGM- 1 cells, miR-203 in SGC7901 and MKN45 cells was significantly downregulated and BIRC5 was upregulated. miR-203 mimic
significantly downregulated BIRC5 in SGC7901 cells, promoted cell apoptosis, and attenuated cell proliferation. Decreased miR-203 expression and increased BIRC5 expression is associated with the pathogenesis of gastric cancer. MiR-203 can inhibit the expression of BIRC5, inhibit proliferation
of gastric cancer cells and induce apoptosis.