bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of lithium-ion indirect liquid cooling battery thermal management system with high discharge rate
Authors: Nizam Muhammad , Putra Mufti Reza Aulia
Published: July 2023

Electric vehicles are developing rapidly and require technological support. Electric vehicles require good power storage. One of the reasonable parameters of a battery pack is its high discharge capability. A high discharge rate requires suitable cell and heat management capabilities in the battery pack. When discharging, it produces heat energy and needs to be released. The battery thermal management system (BTMS) is a method used to maintain battery heat. BTMS using liquid has a better performance compared to phase-change memory (PCM) and air cooling. The use of liquid coolers still has limitations. Namely, the weight of the cooling system is quite large because of a large amount of liquid which increases the weight of the battery. This study offers the potential to use mini channels mounted on cooling plates for application as BTMS. This research used the finite element method (FEM) process by simulating the process of fluid flow that occurs when the battery is used at various C rates. The results of this study indicate that the type of BTMS can keep the battery hot at working temperatures below 40 ºC.
Performance analysis of three-phase induction motor for railway propulsion system
Authors: Kamar Syamsul , Lestari Meiyanne , Soewono Respatya Teguh , Hidayat Sofwan , Luthfiyah Hilda , Qowiy Okghi Adam , Setiawan Fauzi Dwi , Harjono Mulyadi Sinung
Published: July 2023

A three-phase induction motor absorbs the most electric power among other electrical loads. Therefore, three-phase induction motors are the primary electric motors used in industrial applications thanks to their simple construction and easy operation, as well as low cost and low maintenance costs. Efficiency is a critical parameter that characterizes an induction motor as a traction motor. The traction motor is defined as the engine's effectiveness in converting electrical power at its input into mechanical energy by rotating torque on its axis. One way to analyze the efficiency is to use test data obtained from laboratory tests in case-loaded and no-load tests. Calculations using several formulas on the efficiency of an induction motor as a traction motor produce the same result, namely the efficiency of 98.6% by applying variable frequency drive (VFD). The result of laboratory tests and their analysis can be used as a reference for designing three-phase induction motors for railway traction motors, especially traction motors for high-speed trains.
Modeling and design of PV grid integration for GA-PSO based on fluctuating power quality
Authors: Satyanarayana Vanam , Jayasankar Vairavasamy
Published: July 2023

Grid integration of renewable energy systems with majority of which is variable dc and variable ac. For example, solar systems output variable dc, while wind systems output variable ac. Power electronics now plays a significant role in the DC and AC conversion required for the grid. Power electronics now allows dc-coupled systems to be controlled for both active and reactive power, making inductively controlled for improving power quality and synchronizing renewable energy systems. The presence of harmonics in electrical systems indicates that current and voltage are distorted and deviate from sinusoidal waves; odd and even harmonics are the result of a nonlinear load. Voltage and sag and swell are examples of power quality issues, as are filters whose primary purpose is to reduce harmonics, voltage, and current in alternating-current power systems to an acceptable level. The maximum power point tracking is based on maintaining temperature and irradiance variables. We use both proposition and Maximum power point tracking (MPPT) to maximize PV power with oscillation tracking. The genetic algorithm with partial swarm optimization (GA-PSO) algorithm based on various optimization control techniques. Control techniques are proposed for systems with various unbalanced voltages to maintain control operation during fault conditions.
Improved performance of Hexacopter's roll balance control system
Authors: Al Al , Fajrin Fajrin , Effendi Asnal , Bachtiar Antonov , Premadi Aswir
Published: July 2023

One of the obstacles in determining the constant of the proportional integral derivative (PID) control system for the stability of the Hexacopter is due to the dynamic response of the system. Changing the speed and direction of the aircraft's motion through the throttle is translated into a control system concept into a set-point change. If you have used PID control, which is constant, cannot adjust to changes in set-points or external influences, the stability and reliability of the aircraft cannot be guaranteed. This study proposes PID control, with adaptable constants, using a fuzzy logic controller (FLC). The influence of internal changes and factors outside the aircraft control system, in principle, will accumulate on the size of the error and delta-error. Thus, FLC performs tuning for the PID constant according to the error and delta-error. The design of fuzzifications and defuzzification is based on the maximum limit value of error and delta-error, and sets the value of the constant obtained by the Ziegler-Nichols method as the default value. After the real-plant test, the system performance is obtained as follows: settling time = 34mS; peak time 21mS; rise time = 9.2 mS; delay time = 5.7mS; percent overshoot and steady state error = 1%.
Coordination of protective relays in the substation
Authors: Shaikh Shoaib , Shaikh Samha , Soomar Arsalan Muhammad , Shah Syed Hadi Hussain
Published: July 2023

To make an electrical system reliable and cost-effective, its protection coordination is crucial. Protection coordination is a study to determine the trip settings of protective devices. This research proposes protection coordination for Mehran University of Engineering and Technology, Jamshoro, Sindh. This study includes the coordination of relays connected at each department to the main relay connected with the main vacuum circuit breakers (VCB) by using the time characteristic curves (TCC) and time delay setting of relays using ETAP software. This method is used for the trip of a particular circuit breaker at a proper time. Hence, if a fault occurs in any department only that department will be disconnected, and the rest of the departments will remain in a working condition. This study helps to maintain the system’s high reliability.
Application of machine learning controller in matrix converter based on model predictive control algorithm
Authors: Gounder Yasoda Kailasa , Subramanian Sowkarthika
Published: July 2023

Finite control set model predictive control (FCS-MPC) algorithms are famous in power converter for its easy implementation of constraints with cost function than classical control algortihms. However computation complexity increases when swicthing state is high for converters such as matrix converter, multilevel converters and this impose a serious drawback to compute multi-step prediction horizon MPC algorithm which further increases the computation. To overcome the above said difficulty, machine learning based artificial neural network (ANN) controller for matrix converter is proposed. The training data for ANN controller is derived from MPC algorithm and trained offline with an accuracy of 70.3%. The proposed ANN controller shows a similar and better performance than MPC controller in terms of total harmonic distortion (THD), peak overshoot during dynamic change in reference current and dynamic change in load parameter and less computation with less execution time. Further, ANN controller for matrix converter is tested in OPAL-RT using hardware in-loop (HIL) simulation and showed that it outperforms MPC controller.
Model predictive control using Euler method for switched-battery boost-multilevel inverter
Authors: Abdullah Ahmad Takiyuddin , Idrus Sevia Mahdaliza , Ayob Shahrin Md
Published: July 2023

This paper presents the model predictive control (MPC) design using the backward Euler method for an 11-level switched-battery boost multilevel inverter (SBBMLI). The SBBMLI was proposed as the cost-effective solution for the communication power line in a high-speed rail (HSR) system. Initially, a generalized SBBMLI problem formulation was performed, and an open-loop simulation based on voltage and current mode controls was conducted. The finite control set-model predictive control (FCS-MPC) ability to track the reference sinusoidal output with low total harmonic distortion (THD) was then assessed as a performance criterion. Furthermore, the performance was assessed based on no-load and load disturbances. Finally, the results proved the ability of the proposed FCS-MPC to address non-linear dynamics, constraints, and its eﬃciency of implementation.
A non-inverting single-switch buck-boost converter based LED driver
Authors: Maheswaran Devi , Thazhathu Sreedevi Vellithiruthi , Thangavelusamy Deepa
Published: July 2023

This paper focuses on a single-switch buck-boost (SSBB) converter for light emitting diode (LED) lighting applications. The proposed LED driver with power factor correction (PFC) shows enhanced performance in terms of input power factor, efficiency and reduced voltage stress across the switch. The presented LED driver is operated in discontinuous conduction mode (DCM). The input PFC is carried out using average current mode control (ACMC) and the controller is optimized using artificial bee colony (ABC) algorithm. A hardware prototype of 50W LED driver with ACMC for PFC is implemented using a programmable interface circuit (PIC) microcontroller. The experimental results are presented and the performance is compared with a conventional buck boost LED driver. The proposed SSBB LED driver achieves an input power factor of 0.96 with an efficiency of 98%.
Calculation methods of RF power requirement on an RF dee cavity of cyclotron
Authors: Silakhuddin Silakhuddin , Darmawan Rian Suryo , Dwiatmaja Agus , Shali Ahsani Hafizhu , Kudus Idrus Abdul , Taufik Taufik
Published: July 2023

A calculation of the radio frequency radiofrequency (RF) power required to operate the RF dee cavity of cyclotron which of the two dee is in phase has been carried. In this calculation, the object is the RF dee cavity of the DECY-13 cyclotron which operates with an RF frequency of 77.77 MHz and a peak RF dee voltage of 40 kV. The power requirement was determined by calculating the dissipated power in the RF dee that was calculated by two methods. The first method using a relationship between the quality factor and lost power has resulted in the power requirement of 20.55 kW. The second method using a relationship between the electrical current and the lost power has resulted in the power requirement of 19.74 kW. The two results do not seem to have any significant difference. By these calculations, it can be determined the predicted power requirement for operating the RF dee of DECY-13 cyclotron was around 20 kW.
Design and development of modified high efficient high gain DC-DC converter for SPV standalone systems
Authors: Kariyat Vineeth Kumar Pothera , Janardhanan Jijesh Jisha
Published: July 2023

A conventional DC-DC converter is not viable for power conditioning in standalone solar photovoltaic applications. Switching losses are the primary reason for the poor performance of conventional DC-DC converters. To mitigate the issues in conventional DC-DC converters, a high efficient high gain (HEHG) DC-DC converter is designed and developed in this research work. Modified HEHG converter utilizes the passive components switched capacitors, coupled inductor, and resistor capacitor (RC) snubber circuit for minimizing the switching losses and improving the overall power conversion efficiency of the solar photovoltaic (SPV) system. In addition, a modified
 D-sweep maximum power point tracking (MPPT) algorithm is in-corporate into this system to improve the tracking efficiency of the SPV system. HEHG for a standalone system is designed using MATLAB/Simulink environment and developed the hard-ware prototype. As a part of the validation, real-time testing is carried out and compares the performance of the HEHG converter with a traditional DC-DC converter. The theoretical efficiency of the HEHG converter is 96.01%, and the real-time efficiency is 95.62%. Found that theoretical and practical values of performance parameters are closely tallying.
A novel online monitoring system of frequency oscillations based intelligence phasor measurement units
Authors: Hussein Husham I. , Abdullah Ali Najim , Jafar Assama Sahib Jafar
Published: July 2023

In this paper, frequency oscillation has been present as it is an important issue in power systems, especially when it is joined to the new trend to use alternative energies as an energy source, as well as to be a big risk for the inter-connection of the modern electric power networks. Wind farm acts as alternative energy and connected to two buses on the Iraqi power system. Because the low-frequency oscillation monitoring needs be accurate and fast, the main objective is to propose a novel online monitoring system consisting of phasor measurement unit's (PMU) with artificial intelligence neural network (PMU-NN). The location of the phasor measurement units has been optimized using (graph-theoretic procedure algorithm) and the function for the artificial intelligence (NN) is radial basis function (RBFNN). The data information from phasor measurement units is the inputs to the artificial intelligence system then predictions are made Information on low-frequency oscillation (target). The MATLAB toolboxes (PSAT & NN) used to obtain results. Finally, from the results, the validity of the proposed (PMU-NN) system has been proven and tested on the Iraqi power grid (24 bus) in several cases and several places on the network and the comparison was made with the analysis model.
Power factor correction AC-DC boost converter using PI-hysteresis current control
Authors: Shehata Mariam K. , Attia Hossam Eldin Mostafa , Elnaghi Basem E. , Ibrahim Nagwa F.
Published: July 2023

The AC line input voltage is frequently rectified by single-phase diode rectifiers and filtered using sizable electrolytic capacitors. The capacitor draws current in brief pulses, so harmonics distort the line current, resulting in high losses. Harmonics and line current distortions harm the unity power factor and efficiency. This article adopts a simple single-stage AC-DC converter with a high-power factor and low total harmonic distortion. The PI hysteresis current control was utilized to reduce the total harmonic distortion and increase the power factor at full load. The PI controller was added to the outer voltage loop to regulate the output voltage. Ziegler-Nichol's tuning method was used to determine the controller gain levels. Simulation results were obtained for the AC-DC converter at a constant switching frequency to show the benefits of the proposed control method, which has a low total harmonic distortion and a high-power factor compared with cases without a controller. The proposed control method is accurate and efficient for achieving the power factor correction converter. Besides, the proposed control was stable during dynamic and steady-state responses.
Sliding-mode control for boost converters under voltage and load variations
Authors: Shehata Mariam K. , Attia Hossam E. Mostafa , Ibrahim Nagwa F. , Elnaghi Basem E.
Published: July 2023

Boost converters are employed in DC motors, switch-mode power supplies, and other applications. Practical implementation difficulties, reliance on variable-frequency units, and delayed dynamic responses to changes in load and voltage are the main drawbacks of different control methods for the boost converter. In this paper, two techniques were proposed with the target of controlling the boost converter to improve the efficiency of the converter's performance. The two techniques used in this paper depended on fixed-frequency mode instead of variable-frequency mode because of the demerits of the latter factor. The first technique is the sliding-mode control for the AC-DC converter to achieve power factor correction and reduce the harmonic ratio significantly while regulating the output voltage. This technique was used for the DC-DC converter to obtain a rapid dynamic response to control sudden or considerable changes in loads or input voltages with a regulated output voltage. Moreover, the two-loop cascade control is the second proposed technique for the DC-DC converter to achieve an excellent dynamic response under step loads or input voltage variations with an excellently regulated output voltage. Re-simulation results validated the proposed design approach and illustrated the proposed controller's robustness and faster response time.
An investigation of piezoelectric tile with drop test technique for energy harvesting application
Authors: Asry Anis Maisarah Mohd , Mustafa Farahiyah , Yi Sim Sy , Ishak Maizul , Ahmad Aznizam
Published: July 2023

This paper present test and analyses of piezoelectric transducers tile with drop test technique. This piezoelectric tile was tested together with bending mechanism. The bending mechanism was designed using SolidWork software and manufactured by employing 3D printer technology to conduct the evaluation. The piezoelectric transducers connected in a parallel configuration and inserted in piezoelectric tile together with bending mechanism. The drop test employed to test this piezoelectric tile with various loads and speeds. This test conducted based on free fall concept. A wooden box used as a guide to drop an object onto the piezoelectric tile. The various weight load released at a fixed height with different speeds. The output power generated based on the weight and speed of the object were recorded with average force applied on piezoelectric transducer. The highest output power generated was 634.54 µW when 6 kg load released at 2 drop/s with 1.89 N average force applied on each piezoelectric transducer. The lowest output power generated was 6.28 µW when 1 kg load released at 0.5 drop/s with 0.22 N average force applied. The results showed good output power of the piezoelectric transducer was generated for energy harvesting application.
Sliding mode controller with fuzzy supervisor for MPPT of photovoltaic pumping system
Authors: Hamdi Taleb , Elleuch Khaled , Abid Hafedh , Toumi Ahmed
Published: July 2023

This paper focuses on a photovoltaic system for pumping water. The control strategy for this water pumping system is based on Takagi-Sugeno type fuzzy supervisors and sliding mode controller. The first generates the maximum power point current under varying climatic condition whereas the second allows tracking the reference signal produced by the fuzzy supervisor. The system includes a photovoltaic generator (PVG) followed by a DC-DC Converter, DC bus, an AC/DC inverter which is connected to the induction motor. This latter is coupled with a centrifuge pump. The induction motor is driven based on field-oriented control strategy. The Takagi-Sugeno type fuzzy supervisor predicts, depending on the variations of climatic variables such as irradiation and temperature, the optimum operating point for the photovoltaic source. The simulation results show the effectiveness of the proposed approach in transient and stationary regimes for different values of climatic variables.
Modelling and simulation of an on grid 100-kW photovoltaic system
Authors: Abed Adnan Majeed , Alkhazraji Afaneen Anwer , Al-Kubragyi Shatha Suhbat Abdulla
Published: July 2023

This work proposes a design of a solar radiation generator system to extract a maximum power of 100 kilowatts for the uses of 400 volts, 50 Hertz electrical network, under standard conditions (1000 Watts/m2 and 25 °C). The main goal is to inject and control active and reactive power to the grid by a three-phase, one-stage solar grid-connected 100-kW photovoltaic (PV) plant, to keep the current's total harmonic distortion (THD) within the international requirements, and maintain a constant voltage regardless of solar radiation changes. This design consists of three control loops those are: the maximum power point tracking (MPPT), the DC-link voltage, and the current controller. The proposed system was simulated in MATLAB/Simulink environment and was applied on part of the Baghdad electrical network. The obtained results showed the efficiency of the proposed design and modelling.
Simulation of grid connected PV system with PI, fuzzy-GA based controllers for power flow control
Authors: Swarupa Malladi Lakshmi , Latha Kamasamud Sree , Obulesu Dakka
Published: July 2023

Nowadays, renewable energy sources turned into a choice to fulfill the expanding load need since they are ecological inviting and furthermore accessible bountiful in nature. Due to the easy availability of solar-powered vitality, the photovoltaic (PV) system is gaining popularity as a renewable energy option. Most of the energy from a PV array may be dissipated by using the maximum power point tracking (MPPT) method. The force quality problems, the real and responsive force stream problems, are a major concern when transferring a mass measure of intensity from a PV array to the power grid. This research proposes a unique control technique for regulating the power flow and resolving power quality concerns brought on by the integration of PV arrays into an existing power infrastructure. For effective management of real and receptive force stream in matrix related photovoltaic framework, it includes a PI-GA, fuzzy-GA based flowed regulator dealt with adaptable AC transmission framework gadget, specifically static synchronous compensator (STATCOM). As a result, the fuzzy rationale regulator creates a control vector, which is in this way tweaked utilizing a standard calculation.
ANFIS based sliding mode control of a DFIG wind turbine excited by an indirect matrix converter
Authors: Khajeh Ahmad , Torabi Hamed , Siahkaldeh Zahra Shabani
Published: July 2023

Doubly fed induction generator (DFIG) is very popular in commercial turbines installed worldwide. Indirect matrix converter (IMC) is a fully silicon-based converter without capacitor that could be used in wind turbines. In this paper a robust ANFIS based second order sliding mode controller is proposed to control the DFIG wind turbine excited by IMC converter. ANFIS is a combination of fuzzy logic control and artificial neural networks. This hybrid combination could decrease the complexity of the wind turbine system. This scheme does not need the exact mathematical model of the system as needed in classical control methods. The effectiveness of the proposed controller is verified by simulation results compared to the classical PI controller.
Comparative study between PI and SMC controllers for DFIG using fuzzy wind power estimator
Authors: Jemmali Atef , Elleuch Khaled , Abid Hafedh , Toumi Ahmed
Published: July 2023

In this paper, we are interested in the control of the rotor current of the doubly feed induction generator (DFIG), that is used in wind turbines. In this context, we present a comparative study between two types of controllers. The first is based on a classic PI proportional-integral control, while the second is based on the SMC sliding control. The command chain uses a fuzzy estimator of the wind power, which makes it possible to determine the reference speed of DFIG. The system includes essentially a turbine, two converters, one on the rotor side and the other on the grid side, and a filter. The grid-side converter is used to maintain a constant DC bus voltage and to control rotor reactive power. The rotor side converter is used to control the speed of the DFIG to guarantee maximum power extracted from the turbine. In addition, this converter allows controlling the reactive power through the control of the rotor current according to the axis "d" of the frame linked to the rotating field. The simulation results show the effectiveness of sliding mode control (SMC) for the considered system.
Improvement of power quality of a 200 kW grid-connected PV system
Authors: Saini Manoj , Khan Shagufta , Sharma Amit Kumar , Chaudhary Sunil Kumar , Srivastava Kiran , Srivastava Puneet Chandra , Saini Sumit
Published: July 2023

In order to enhance electricity quality, a grid-connected photovoltaic (PV) system simulation is presented in this study. A 200 kW photovoltaic system is integrated to a utility grid and loads. A 25 kV 3-level insulated gate bipolar transistor (IGBT) bridge converter is used. Through this system integration of a renewable energy source with a non-renewable source is achieved. This system also wins over the intermittent nature of the renewable source (solar energy) and non-reliability of conventional sources (utility grid). Power and signal quality for various signals such as ripple factor and total harmonic distortion has improved. The suggested system is investigated using MATLAB/Simulink environment. Total harmonic distortion (THD) in voltage and current, ripple factor correction is also incorporate in the MATLAB model.
A state of the art a hybrid intelligent strategies of maximum power point tracking: a systematic contemporary
Authors: Shalal Abbas Fakhri , Aljanabi Mohanad , Al-Shamani Ali Najah , Duhis Ahmed Hussein
Published: July 2023

Renewable energy sources are among the best substitute sources to fossil fuel due to it is very suitable for mitigating global warming; solar energy is considered the main causes of renewable energy, and solar photovoltaic (PV) generation systems have gained importance worldwide due to several characteristics, including cheap maintenance, low noise, and low fuel costs. However, one of the most difficult challenges facing solar energy systems is changing weather circumstances. The robust control approach stabilizes the PV system's output and maximizes harvested energy. In this study, several maximum power point tracking (MPPT) performances have been presented. Among them, artificial intelligence (AI) based on MPPT methods demonstrates the ability to capture the MPP point. There are several ways to apply AI to MPPT, and this paper presented various intelligent MPPT methods in detail with their benefits and drawbacks and comparison among them to select which technique is suitable and can be used to change weather conditions with horse optimization method (HOM) plus neural artificial system (NAS).
Model predictive current control for maximum power point tracking of voltage source inverter based grid connected photovoltaic system
Authors: Burada Satyanarayana , Padma Kottala
Published: July 2023

Due to the high demand of grid connected photovoltaic systems, there is a need to track the maximum power point of the PV system. As the output of PV system is dc, there should be a converter, acting as medium between PV system and dc bus capacitor to track maximum power at all the loads. Usually boost converter is acting as medium between PV system and dc link capacitor as the duty cycle of the insulated-gate bipolar transistor in boost converter is in between 0 to 1 for maximum loads during maximum power point tracking (MPPT). To make PV system stable, the balance point is dc bus. If the dc bus voltage is constant, the system will be stable. Then the transfer power will just depend on current. For this purpose, the active current reference signal is to be generated by setting up the reference voltage across dc bus. Here to generate active reference current, PI controller is used and the reference voltage is taken according to the peak voltage of the inverter output voltage. The proposed control strategy was evaluated on a three-phase inverter linked to the grid and supplied by the PV system, which is working under varying irradiation conditions.
A special method for simultaneous optimization of electrical grid interconnections and cable size in wind farms
Authors: Al-Khafaji Fareed Kadhim Hussein , Al Humaidani Ali Abdul Hussein Kareem , Aljaberi Adiy , Zaid Iman Mohammed Abd
Published: July 2023

Modern wind farms are considered one of the most important sources of energy today. The biggest cost of the farm is the cost of electrical connection to the farmers (constituting the largest part of the aesthetic cost of the farm) and finding the best method for electrical connection (the optimal method) for wind turbines (WTS), as well as the optimal size and measurement of electrical cables. Here, the (harmonious) search algorithm solves the optimization problem and the method of digging the soil in order to lay the cables in it. Two cases will be discussed in order to calculate the optimal size of the cables, namely partial calculation and optimal calculation for connection schemes in the best method for wind farms (OWFS). Also, the total cost, shipping methods, methods of digging extensions into the soil and the different classifications for turbines (wind turbines) will be addressed in order to obtain the best investment for them, so that we reach the optimal delivery and the lowest possible cost in a coordinated and thoughtful manner.
Design a 25-level inverter topology with less switching devices fed by PV systems
Authors: Ali Ali Riyadh , Abdulghafoor Abdulghani Abdulrazzaq , Antar Rakan Khalil
Published: July 2023

Multilevel inverter (MLI) technology has lately emerged as one of the most popular solutions for high power and medium voltage energy management. MLIs have many benefits and require more switches for higher levels, which are considered disadvantaged. This could result in large size and extremely expensive cost for the MLI. So, in order to overcome this problem, a new MLI topology is proposed with reduced number of switches. A 25‐level inverter fed by isolated unequal photovoltaic panels as DC sources is chosen in this study. The structure of DC voltages is chosen as (1:1:5:5) Vdc. The proposed approach, which is created using twelve switches, is ideally suited for a high-power application. Multi-carrier with a sinusoidal PWM technique is programmed as a controller. According to the simulation findings, a single-phase system's output voltage and current total harmonic distortion (THD) values are 1.2% and 0.462%, respectively, while a three-phase system's values are 1.07% and 0.342%. These findings prove that the power circuit and investigation were successful.
Modeling and optimization of PV-diesel-biogas hybrid microgrid energy system for sustainability of electricity in Rural Area
Authors: Araoye Timothy Oluwaseun , Ashigwuike Evans Chinemezu , Umar Sadiq Abubakar , Eronu Emmanuel M. , Ozue Thank God Izuchukwu , Egoigwe Sochima Vincent , Mbunwe Muncho Josephine , Odo Matthew Chinedu Odo , Ajah Nnaemeka Genesis
Published: July 2023

The paper presented a hybrid micro-grid renewable energy of different energy sources to generate uninterrupted electricity for the Agu-Amede village using PV, diesel, biogas, and battery. The system optimization was performed to determine techno-economic analysis and energy generated using HOMER software. The energy generated by the hybrid system was able to meet the demand load of the village at all levels of biomass production with surplus electricity in each case when the production of the biogas system varied between 0.5 tons to 3 tons. At biomass production of 3 tons, the total energy generated demand is 480693 kWh with a surplus of 121762 kWh. Again, the hybrid PV and biogas system generate total energy of 98714 kWh (20.50%) and 381979 kWh (79.50%), respectively. The net present cost (NPC) and cost of energy (COE) of the base case architecture (diesel) measured are $1230000 and $0.267/kWh, respectively. Therefore, between 2.5 tons and 3.0 tons of biomass penetration, the energy production of biogas increased, and the diesel system was removed from the hybrid system setup. This is because the availability of biogas is almost sufficient to meet the load demand at a lower cost and solar PV architecture was added to the hybrid system to balance energy production.
Wind energy conversion system based on DFIG using three-phase AC-AC matrix converter
Authors: Blouh Fatima-ezzahra , Boujidi Basma , Bezza Mohamed
Published: July 2023

Due to the development of power electronics technology, the use of a new generation of power converter AC-AC matrix converters has received special attention, which provides direct power converter AC-AC, bidirectional power flow, near-sinusoidal input, and output waveforms. The performance analysis of a variable-speed wind turbine based on a doubly fed induction generator and connected to the main grid through a three-phase matrix converter is presented in this paper. Additionally, this paper proposes the utilization of a space vector modulation approach in the three-phase matrix converter. Other benefits of the space vector modulation approach include lower total harmonic distortion of output voltage and lower switching loss. The simulation analysis of the proposed power conversion system using MATLAB/Simulink/SimPowerSystems toolbox R2021a is presented in this paper.
Short term load forecasting using evolutionary algorithm for Tajikistan
Authors: Hussein Balasim M. , Abood Hatim Ghadhban , Firuz Mahmadjonov , Nadtoka Ivan Ivanovich
Published: July 2023

Load forecasting is a significant element in the energy management system of power systems. Precise load forecasting aids electric utilities to conduct decisions of unit commitment, reduction of spinning reserve capacity, and schedule device maintenance plan. Furthermore, load forecasting contributes to reducing the generation cost, and it is fundamental to the reliability of the power systems. On the other hand, short-term load forecasting is substantial for economic running. The forecasting precision directly affects the reliability, economy running and supplying power quality of the power system. Hence, finding the required load forecasting method to enhance the accuracy is valuable for forecasting precision. This paper proposed particle swarm optimization (PSO) to improve working support vector machine (SVM), SVM regression model is derived; also derived SVM with PSO. Support vector machine (SVM) model is adopted with and without PSO based on the historical load data and meteorological data of Tajikistan country, analysis the various factors affecting the forecast. The historical data and the load forecasting factors to be considered are normalized. The two parameters of SVM significantly influenced the model, and therefore it optimized using evolutionary algorithm.
Como surgem sociedades divididas?
Authors: Barros José Vitor Silva , Stichweh Rudolf
Published: July 2023

O artigo analisa forças divisivas nas sociedades contemporâneas e as conecta às esperanças incumpridas oriundas das revoluções do início da modernidade: as esperanças por igualdade, liberdade e fraternidade/solidariedade. Antes de tudo, no século XXI, podemos dizer que há desigualdades persistentes que emergem em todos os sistemas funcionais da sociedade e tornam-se divisivas assim que eclode uma cisão descontínua na distribuição de ganhos. Cisão esta que torna improvável que alguém se movimente de um lado ao outro da distribuição. Em segundo lugar, há fortes dependências assimétricas vinculadas a um aumento dos controles por parte de pessoas e grupos que controlam recursos desejados por outros; essas dependências, por sua vez, fortalecem o acréscimo dos controles dos primeiros sobre os últimos, seja sobre ações, comunicações, opções de saída e/ou modos de perceber o mundo. Quanto maiores as dimensões de controle presumidas numa relação social dada, mais fortes e pervasivas as dependências assimétricas, as quais separam a sociedade entre aqueles que exercem controles e aqueles que são objeto de controle. Há ainda, em terceiro lugar, como estrutura de divisão, a ascensão da polarização sociocultural. Ela cria uma cisão entre subcomunidades significantes de uma sociedade com base em quais comunidades percebem os membros de outras como perigosos e estranhos aos valores e formas de vida considerados essenciais para a própria comunidade. O artigo explica, por fim, tais divisões societais ao estudá-las como formas de inclusão e exclusão. Desigualdades advêm de acumulação nas dinâmicas de inclusão dos sistemas funcionais; dependências assimétricas emergem em instituições e grupos que absorvem pessoas excluídas de participações relevantes em experiências e cursos de ação; polarizações baseiam-se nas exclusões recíprocas e totalizantes pelas quais comunidades definem membros de outras comunidades como ‘outros’ radicais.
As sugar babies são empresas e os sugar daddies são investidores-anjo: uma análise sobre os relacionamentos sugar e suas vinculações com elementos de uma racionalidade neoliberal
Authors: Leite Júnior Jorge , Barbosa Bruno Henrique Benichio Alves
Published: July 2023

Os relacionamentos sugar heterossexuais são compostos pelos sugar daddies e pelas sugar babies. A ajuda financeira é um fator imprescindível para essas configurações, uma vez que elas presumem cenários em que um sugar daddy arca com os gastos financeiros e aspirações de consumo de uma sugar baby conforme as negociações que ambos fazem entre si ao decorrer do vínculo. Majoritariamente, essas pessoas se conhecem através de sites de relacionamentos que prometem conectá-las. Este artigo apresenta uma análise acerca das diferenças, como as de gênero, classe, raça e idade, e de uma racionalidade neoliberal em relacionamentos sugar, exprimindo o percurso de uma etnografia realizada em contextos digitais que coletou e analisou os seguintes dados: 1) Perfis de sugar babies em um site de busca por relações sugar; 2) Entrevistas com sugar babies; 3) Publicações do site em suas vias digitais de divulgação. De modo geral, constata-se que esses relacionamentos se configurammediante hierarquias sociais fundamentadas em desigualdades de gênero, classe e raça, e visualiza-se a operacionalidade de uma racionalidade neoliberal que inculca nesse meio o empreendedorismo de si como condição fundamental para o encontro do par ideal.
Off/On: La construcción de la identidad virtual a través de la socialización por videojuegos y la producción de nuevas relaciones sociales en los márgenes de lo virtual y lo no virtual
Authors: Caro Villegas Cristóbal , Marambio-Tapia Alejandro
Published: July 2023

Es artículo nos invita a pensar sobre relaciones entre lo off-line-online en varias dimensiones: capacidad de agencia, socializaciones, identidades y qué es lo virtual/real. A través de un análisis del videojuego World of Warcraft y parte de su comunidad intentamos comprender como funciona su espacio social virtual, cuáles son las reglas que posee este espacio, de qué manera los videojugadores conforman su propia identidad virtual, y como dialogan y tensión a lo off y lo online. A través de entrevistas semi-estructuradas y observación participante virtual se recogen datos que pretenden ilustrar la argumentación respecto a las nuevas formas de construir la socialización y las relaciones sociales, y como deambulan desde lo superficial a lo más significativo, en un eje, y desde lo virtual a no virtual, en otro eje.
Intelectuais, Estado e experiência política: a trajetória de Darcy Ribeiro
Authors: Mattos André Borges de
Published: July 2023

O artigo analisa a trajetória intelectual de Darcy Ribeiro entre os anos de 1944 e 1964. O período compreende a sua passagem como estudante pela Escola Livre de Sociologia e Política de São Paulo, posteriormente pelo Serviço de Proteção aos Índios, pelo Centro Brasileiro de Pesquisas e Educacionais e por cargos do executivo durante o governo de João Goulart. O objetivo é discutir em que medida essas experiências, vivenciadas junto ao Estado e às elites estatais, nos anos iniciais de sua atuação profissional, ajudam a explicar a visão de mundo de Darcy Ribeiro, amplamente difundida em sua obra, sobre a ciência, o trabalho intelectual e os problemas nacionais. Com isso, espera-se uma contribuição para futuros estudos sobre trajetórias intelectuais e sobre as relações entre intelectuais e Estado no Brasil.
Darcy Ribeiro, um etnógrafo do Brasil
Authors: Moreira Gisele Jacon de Araujo
Published: July 2023

Darcy Ribeiro, antropólogo e político brasileiro, foi um homem com muitos atributos intelectuais e assumiu posições importantes na política nacional.  Publicou seis volumes de estudos antropológicos, com mais de mil páginas, sobre a formação do povo brasileiro no âmbito das configurações histórico-culturais das Américas e das nações mundiais. Este artigo passeia pelos registros etnográficos dos primeiros anos de vida profissional de Darcy como etnólogo da Seção de Estudos do Serviço de Proteção aos Índios entre 1947 e 1957. Propõe que a originalidade de sua interpretação sobre a formação do povo brasileiro deriva do conhecimento que adquiriu nos anos de vivência e estudo entre os índios e os efeitos do contato violento daqueles povos com as frentes de expansão da civilização. Conclui destacando a importância do seu romance Maíra na literatura e na antropologia brasileiras da segunda metade do Século XX, como um registro crítico e irônico da ciência etnográfica pura e imparcial com relação ao drama indígena na modernidade.
Dois corações simples: uma leitura de Mário de Andrade e Jean Paul
Authors: Anan Sylvia Tamie
Published: July 2023

Ao chamar de “idílio” sua obra Amar, verbo intransitivo (1927), Mário de Andrade propôs um enigma para leitores e críticos a respeito do significado do termo e suas consequências para o texto. Tendo em vista as inúmeras referências à literatura e à cultura clássica alemãs e seu caráter estruturante dentro da narrativa, é possível analisar a hipótese de que Andrade se valia da definição de Jean Paul (1763-1825) para o idílio, tal como apresentada em sua Vorschule der Ästhetik (1804) e em Leben des vergnügten Schulmeisterlein Maria Wutz in Auental (1793), outra narrativa sobre um professor denominada “idílio”. Desse modo, tanto Fräulein Elza quanto Maria Wutz seriam protagonistas de um romance lírico que retrata um estado de plenitude, percebido apenas em função da distância tomada por um narrador capaz de descrever os limites externos de sua existência.
Association Between Maternal Glucose Levels in Gestational Diabetes Screening and Subsequent Hypertension
Authors: Liang Xinyun (Christie) , Savu Anamaria , Ngwezi Deliwe , Butalia Sonia , Kaul Padma , Yeung Roseanne O.
Published: July 2023

BACKGROUND:

We assessed the association between maternal glucose levels in pregnancy and subsequent hypertension.

METHODS:

This population-level, retrospective cohort study examined women aged 12 to 54 years with singleton pregnancies completed at ≥29 weeks of gestation from October 1, 2008 to December 1, 2018 followed until March 31, 2019 in Alberta, Canada. Women were stratified by results in the 50-gram glucose challenge test and by 75-gram oral glucose tolerance test subtypes (normal oral glucose tolerance test, elevated fasting plasma glucose only [elevated fasting], elevated postload glucose only, or both elevated fasting and postload glucose [combined]. Time to development of hypertension was modeled using Cox proportional hazards models.

RESULTS:

Of 313 361 women, 231 008 (79.1%) underwent a glucose challenge test only while 60 909 (20.9%) underwent either an oral glucose tolerance test only or both. Nine thousand five hundred eighty (3.1%) developed hypertension, and 2824 (0.9%) developed cardiovascular disease over a median follow-up of 5.7 years. Every 1-mmol/L increase in glucose in the glucose challenge test increased the risk of subsequent hypertension by 15% (adjusted hazard ratio and 95% CI, 1.15 [1.14–1.16]). Among those who underwent the oral glucose tolerance test, the combined group conferred the highest risk of subsequent hypertension, followed by elevated fasting, then elevated postload glucose only (reference: glucose challenge test ≤7.1 mmol/L, adjusted hazard ratio [95% CI]: elevated postload glucose only, 1.83 [1.68–2.00]; elevated fasting 2.02 [1.70–2.40]; combined, 2.65 [2.33–3.01]). No significant associations between maternal glucose levels and cardiovascular disease were observed.

CONCLUSIONS:

Increasing maternal glucose levels in pregnancy were associated with increasing risk of subsequent hypertension. These findings may help identify higher-risk women who should be targeted for earlier postpartum cardiovascular risk reduction.
Splanchnic Nerve Modulation Effects on Surrogate Measures of Venous Capacitance
Authors: Kittipibul Veraprapas , Ganesh Arun , Coburn Aubrie , Coyne Brian J. , Gray James Matthew , Molinger Jeroen , Ray Neil , Podgoreanu Mihai , McCartney Sharon L. , Mamoun Negmeldeen , Fitzhugh Robert Curtis , Lurz Philipp , Green Cynthia L. , Hernandez Adrian F. , Patel Manesh R. , Fudim Marat
Published: July 2023

Background

Splanchnic nerve modulation (SNM) is an emerging procedure to reduce cardiac filling pressures in heart failure. Although the main contributor to reduction in cardiac preload is thought to be increased venous capacitance in the splanchnic circulation, supporting evidence is limited. We examined changes in venous capacitance surrogates pre‐ and post‐SNM.

Methods and Results

This is a prespecified analysis of a prospective, open‐label, single‐arm interventional study evaluating the effects of percutaneous SNM with ropivacaine in chronic heart failure with elevated filling pressures at rest and with exercise. Patients underwent cardiopulmonary exercise testing with invasive hemodynamic assessment pre‐ and post‐SNM. Blood pressure changes with modified Valsalva maneuver and hemoconcentration, pre‐ and post‐SNM were compared using a repeated measures model. Inferior vena cava diameter and collapsibility (>50% decrease in size with inspiration), and presence of bendopnea pre‐ and post‐SNM were also compared. Fifteen patients undergoing SNM (age 58 years, 47% women, 93% with left ventricular ejection fraction ≤35%) were included. After SNM, changes in systolic blood pressure during Valsalva (peak‐to‐trough) were greater (41 versus 48 mm Hg,
P
=0.025). Exercise‐induced hemoconcentration was unchanged (0.63 versus 0.43 g/dL,
P
=0.115). Inferior vena cava diameter was reduced (1.59 versus 1.30 cm,
P
=0.034) with higher collapsibility (33% versus 73%,
P
=0.014). Bendopnea was less (47% versus 13%,
P
=0.025).

Conclusions

SNM resulted in increased venous capacitance, associated decreased cardiac preload, and decreased bendopnea. Minimally invasive measures of venous capacitance could serve as markers of successful SNM. Long‐term effects of SNM on venous capacitance warrant further investigation for heart failure management.

Registration

URL:
https://www.clinicaltrials.gov
; Unique identifier: NCT03453151.