Improving frequency response for AC interconnected microgrids containing renewable energy resources

Interconnecting two or more microgrids can help improve power system performance under changing operational circumstances by providing mutual and bidirectional power assistance. This study proposes two interconnected AC microgrids based on three renewable energy sources (wind, solar, and biogas). The wind turbine powers a permanent magnet synchronous generator. A solar photovoltaic system with an appropriate inverter has been installed. In the biogas generator, a biogas engine is connected to a synchronous generator. M1 and M2, two interconnected AC microgrids, are investigated in this study. M2 is connected to a hydro turbine, which provides constant power. The distribution power loss, frequency, and voltage of interconnected AC microgrids are modeled as a multi-objective function (OF). Minimizing this OF will result in optimal power flow and frequency enhancement in interconnected AC microgrids. This research is different from the rest of the research works that talk about the virtual inertia control (VIC) method, as it not only improves frequency using an optimal controller but also achieves optimal power flow in microgrids. In this paper, the following five controllers have been studied: proportional integral controller (PI), fractional-order PI controller (FOPI), fuzzy PI controller (FPI), fuzzy fractional-order PI controller (FFOPI), and VIC based on FFOPI controller. The five controllers are tuned using particle swarm optimization (PSO) to minimize the (OF). The main contribution of this paper is the comprehensive study of the performance of interconnected AC microgrids under step load disturbances, the eventual grid following/forming contingencies, and the virtual inertia control of renewable energy resources used in the structure of the microgrids, and simulation results are recorded using the MATLAB™ platform. The voltages and frequencies of both microgrids settle with zero steady-state error following a disturbance within 0.5 s with less overshoots/undershoots (3.7e-5/-0.12e-3) using VIC. Moreover, the total power losses of two interconnected microgrids must be considered for the different controllers to identify which one provides the best optimal power flow

Optimal Power Management of Interconnected Microgrids Using Virtual Inertia Control Technique

Two interconnected AC microgrids are proposed based on three renewable energy sources (RESs): wind, solar, and biogas. The wind turbine drives a permanent magnet synchronous generator (PMSG). A solar photovoltaic system (SPVS) with an appropriate inverter was incorporated. The biogas genset (BG) consists of a biogas engine coupled with a synchronous generator. Two interconnected AC microgrids, M1 and M2, were considered for study in this work. The microgrid M2 is connected to a diesel engine (DE) characterized by a continuous power supply. The distribution power loss of the interconnected AC microgrids comprises in line loss. The M1 and M2 losses are modeled as an objective function (OF). The power quality enhancement of the interconnected microgrids will be achieved by minimizing this OF. This research also created a unique frequency control method called virtual inertia control (VIC), which stabilizes the microgrid frequency using an optimal controller. In this paper, the following five controllers are studied: a proportional integral controller (PI), a fractional order PI controller (FOPI), a fuzzy PI controller (FPI), a fuzzy fractional order PI controller (FFOPI), and a VIC based on FFOPI controller. The five controllers were tuned using particle swarm optimization (PSO) to minimize the (OF). The main contribution of this paper is the comprehensive study of the performance of interconnected AC microgrids under step load disturbances, stepn changes in wind/solar input power, and eventually grid following/forming contingencies as well as the virtual inertia control of renewable energy resources used in the structure of the microgrid

Fabrication of garlic composites nano-biotics and investigating their anti-bacterial activities

Bacterial infections are considered the second main cause of death worldwide and the third main cause of death in the developed countries and as a result, many antibacterial coatings have been prepared in order to fight the different strains of bacteria and decrease the mortality rates. Natural antibacterial products become of great interest nowadays and their use is preferred over the synthetic products in order to overcome the resistance to the synthetic antibiotics. A wide variety of antibacterial coatings have been developed ranging from polymeric to polymer Nano-composites (PNCs) materials. Using nanomaterials as fillers within polymer matrices have been reported to enhance the antibacterial properties significantly. The polymeric nanoparticles (NPs) are promising for natural antibacterial drug delivery. In this study, two types of Garlic oil nano-composites (GO-NCs) have been developed by using two polymers which are poly lactic-co-glycolic (PLGA) and poly lactic-co-glycolic/poly ethylene glycol (PLGA/PEG) mixed with garlic oil (GO). The two polymer Nano-composites were named PLGA-GO-NCs and PLGA-PEG-GO-NCs respectively. Single emulsion/solvent evaporation (SE/SE) technique was involved in the preparation of the different nanocomposite formulations. The polymers conjugated with GO were prepared at three different homogenization time intervals (5, 10 and 15 min.) at the same homogenization speed of 11,000 rpm. All the preparation parameters, such as the concentration of polymers, concentration of GO, amounts of surfactant used (polaxmer 407) and the homogenization speed, were kept constant to identify the effect of the homogenization time on the physicochemical properties and the antibacterial activities of the PNCs. In addition, the effect of other factors such as the effect of solution settling, the use of Buchner funnel in solution filtration, the use of biological filters in solution filtration and the effect of mechanical shaking the solutions by using vortex stirring on the different formulations were carefully examined. The particle sizes, zeta potential and poly dipsersity index (PDI) and GO% in each formulation have been measured. The morphological examination of the prepared nanocomposite formulations was carried out by using Scanning Electron Microscope (SEM), and the chemical structural characteristics were examined by using Fourier Transform-Infra-red spectroscopy (FT-IR) and Ultraviolet-Visible spectrophotometry (UV-vis). In addition, antibacterial assessment has been carried out against Eichercia Coli (E. coli) (ATCC 8739) as a Gram-negative bacterium, and Staphylococcus aureus (S. aureus) (ATCC 6538) as a Gram-positive bacterium using Colony Counting Method (CCM). The results revealed four important factors that need to be considered during the preparation of GO NPs which are (i) settling of the solutions, (ii) filtration through biological filters, (iii) Buchner filtration and (iv) vortex stirring of solutions. These factors play a crucial role in controlling the size and stability of PNCs. Furthermore, we have observed that the addition of PEG to the PLGA-GO formulations has a significant effect on decreasing the particle sizes and increasing the GO% in the formulations. These results could be promising in producing polymeric drug/extract NPs of small particle sizes, high stability and of pronounced antibacterial activity which is stronger than the original dtug/extract

Microgripper design and evaluation for automated µ-wire assembly: a survey

Microgrippers are commonly used for micromanipulation of micro-objects from 1 to 100 µm and attain features of reliable accuracy, low cost, wide jaw aperture and variable applied force. This paper aim is to review the design of different microgrippers which can manipulate and assemble µ-wire to PCB connectors. A review was conducted on microgrippers’ technologies, comparing fundamental components of structure and actuators’ types, which determined the most suitable design for the required micromanipulation task. Various microgrippers’ design was explored to examine the suitability and the execution of requirements needed for successful micromanipulation

Study on Magnetic Control Systems of Micro-Robots

Magnetic control systems of micro-robots have recently blossomed as one of the most thrilling areas in the field of medical treatment. For the sake of learning how to apply relevant technologies in medical services, we systematically review pioneering works published in the past and divide magnetic control systems into three categories: stationary electromagnet control systems, permanent magnet control systems and mobile electromagnet control systems. Based on this, we ulteriorly analyze and illustrate their respective strengths and weaknesses. Furthermore, aiming at surmounting the instability of magnetic control system, we utilize SolidWorks2020 software to partially modify the SAMM system to make its final overall thickness attain 111 mm, which is capable to control and observe the motion of the micro-robot under the microscope system in an even better fashion. Ultimately, we emphasize the challenges and open problems that urgently need to be settled, and summarize the direction of development in this field, which plays a momentous role in the wide and safe application of magnetic control systems of micro-robots in clinic

Neuro-fuzzy modelling and control of robotic manipulators

The work reported in this thesis aims to design and develop a new neuro-fuzzy control system for robotic manipulators using Machine Learning Techniques, Fuzzy Logic Controllers, and Fuzzy Neural Networks. The main idea is to integrate these intelligent techniques to develop an adaptive position controller for robotic manipulators. This will finally lead to utilising one or two coordinated manipulators to perform upper-limb rehabilitation. The main target is to benefit from these intelligent techniques in a systematic way that leads to an efficient control and coordination system. The suggested control system possesses self-learning features so that it can maintain acceptable performance in the presence of uncertain loads. Simulation and modelling stages were performed using dynamical virtual reality programs to demonstrate the ideas of the control and coordination techniques. The first part of the thesis focuses on the development of neuro-fuzzy models that meet the above requirement of mimicking both kinematics and dynamics behaviour of the manipulator. For this purpose, an initial stage for data collection from the motion of the manipulator along random trajectories was performed. These data were then compacted with the help of inductive learning techniques into two sets of if-then rules that form approximation for both of the inverse kinematics and inverse dynamics of the manipulator. These rules were then used in fuzzy neural networks with differentiation characteristics to achieve online tuning of the network adjustable parameters. The second part of the thesis introduces the proposed adaptive neuro-fuzzy joint-based controller. To achieve this target, a feedback Fuzzy-Proportional-Integral-Derivative incremental controller was developed. This controller was then applied as a joint servo-controller for each robot link in addition to the main neuro-fuzzy feedforward controller used to compensate for the dynamics interactions between robot links. A feedback error learning scheme was applied to tune the feedforward neuro-fuzzy controller online using the error back-propagation algorithm. The third part of the thesis presents a neuro-fuzzy Cartesian internal model control system for robotic manipulators. The neuro-fuzzy inverse kinematics model of the manipulator was used in addition to the joint-based controller proposed and the forward mathematical model of the manipulator in an adaptive internal model controller structure. Feedback-error learning scheme was extended to tune both of the joint-based neuro-fuzzy controller and the neuro-fuzzy internal model controller online. The fourth part of the thesis suggests a simple fuzzy hysteresis coordination scheme for two position-controlled robot manipulators. The coordination scheme is based on maintaining certain kinematic relationships between the two manipulators using reference motion synchronisation without explicitly involving the hybrid position/force control or modifying the existing controller structure for either of the manipulators. The key to the success of the new method is to ensure that each manipulator is capable of tracking its own desired trajectory using its own position controller, while synchronizing its motion with the other manipulator motion so that the differential position error between the two manipulators is reduced to zero or kept within acceptable limits. A simplified test-bench emulating upper-limb rehabilitation was used to test the proposed coordination technique experimentally

Gabal Ghorabi (El Bahariya Çöküntüsü, Batı Çölü, Mısır) Madenindeki Eosen Demirtaşlarının Stratigrafik Konumu ve Mineralojik İncelemesi

Eocene ironstone of Gabal Ghorabi mine area (El Bahariya depression, Egypt), represents an unconformity-bounded condensed succession, exhibiting a lateral facies change towards the equivalent relatively thicker carbonates of the surrounding scarps. It rests unconformably on different horizons of the underlying folded Cenomanian Bahariya Formation and is subdivided into two main shallowing-upward ironstone sequences, separated by an intra-Eocene (paleokarst) unconformity. The lower ironstone sequence comprises four ironstone facies namely: a) lagoonal/tidal flat mud-ironstone facies, b) lagoonal fossiliferous ironstone facies (proximal tempestite), well developed in the southern sector of Gabal Chorabi mine area, c) shallow subtidal-intertidal nummulitic-ooidal-oncoidal ironstone facies, dominated in the southern and central sectors of Gabal Chorabi, and d) Shallow subtidal nummulitic ironstone facies, that dominated in the northern sector. The upper ironstone sequence begins by the deposition of shallow subtidal green mudstone facies as a result of a new marine transgression followed by a peritidal ironstone sequence, which consists of three repeated shallowing-upward cycles. The upper ironstone sequence is intensively lateritized and karstified and iron ore laterite and stratabound karst-related barite are formed. The main valuable minerals founded in the area are haematite and goethite, and the main gangue minerals are quartz, dolomite, apatite and barite.Cabal Ghorabi maden alanındaki (El Bahariya depresyonu, Mısır) Eosen demirtaşı, eşleniği olan çevredeki yüksek yerlerin daha kalın karbonatlarına yatay fasiyes değişikliği gösteren, uyumsuzlukla sınırlanmış sıkı bir istifi temsil eder. Senomanian yaşlı, kıvrımlanmış Bahariya Formasyonu üzerinde uyumsuzlukla yer alan Eosen demirtaşı, intra-Eosen (paleokarst) uyumsuzluğu ile ayrılan ve yukarı doğru sığlaşan iki ana demirtaşı istifine ayrılır. Alt demirtaşı sekansı dört demirtaşı fasiyesinden oluşur; a) lagünel/gel-git düz çamur-demirtaşı fasiyesi; b) Gabal Chorabi maden alanının güney kesiminde iyi gelişmiş lagünel fosilli demirtaşı fasiyesi (başlangıç evre fırtına çökeli); c) Gabal Chorabinin merkez ve güney kesiminde yoğunlaşmış, sığ, gel-git altı ve içi numulitik-ooidal-onkoidal demirtaşı fasiyesi; d) kuzey kesimde belirgin, sığ gel-git altı numulitik demirtaşı fasiyesi. Üst demirtaşı istifi, yeni bir deniz ilerlemesi sonucu oluşan sığ, gel-git altı yeşil çamurtaşı fasiyesinin depolanmasıyla başlar, ve üç kez tekrarlanan ve yukarıdoğru sığlaşan çevrimden oluşan gelgit içi ve üstü demirtaşı istifi ile devam eder. Üst demirtaşı istifi yoğun olarak lateritleşmiş ve karstlaşmış, ve demir cevheri lateriti ve tabaka dokanaklı karst-ilişkili barit oluşmuştur. Çalışma alanında bulunan başlıca eonomik mineraller, hematite ve götit, ve ana gang mineralleri ise kuvars, dolomit, apatit ve barittir

Efectos del entrenamiento con tapiz rodante en la saturación de oxígeno, distancia caminada y VO2max en la tercera edad

Antecedentes. La actividad física juega un papel importante en la mejora de la función cardiopulmonar y oxigenación arterial de la sangre (SaO2) en los ancianos. Objetivo. Evaluar la eficacia terapéutica de los ejercicios en el tapiz rodante en la SaO2, el consumo máximo de oxígeno (VO2max) y la distancia caminada máxima en sujetos ancianos sanos. Diseño. Estudio de intervención en El Hospital General del Salam, El Cairo (Egipto). Participantes. 82 sujetos (41grupo de intervención y 41 grupo de control, 20 hombres y 21 mujeres en cada grupo, edad media 65,1 ± 2,7 años, rango 60-69. Todos los participantes sanos, sin enfermedades crónicas, que superaron la prueba de esfuerzo cardiopulmonar. Intervención. Los participantes fueron incorporadas en un programa de ejercicio en el tapiz rodante de intensidad moderada para alcanzar una fracción de 60% a 70% de la máxima frecuencia cardiaca del corazón. Después 12 semanas de actividad física controlada, el programa se hizo voluntariamente durante 36 semanas. Mediciones. SaO2, VO2max y máxima distancia caminada se midieron para cada individuo una semana antes y 12 semanas después de la formación y en la 30 ª y la 48 ª semana del programa. Estadística descriptiva: media, desviación estándar (± DE) y rango para los datos numéricos; frecuencia y el porcentaje para los datos no-numéricos por analítica estadística: los niveles de la t de Student, ANOVA, test post hoc, Chi-cuadrado, prueba t pareada y regresión lineal (o nivel significativo: ns = p> 0,05, s = p <.05; hs = p <.01. Resultados. En el grupo de intervención ha habido un aumento en los valores medios de SaO2, VO2max y la distancia máxima caminada después de las 12 semanas de ejercicio controlado y también en la semana 30 y la semana 48 del programa (P <0,05). Ha habido una disminución en los valores medios de VO2max, SaO2 y la distancia máxima caminada después de la semana 30 y 48 en comparación con los valores de las primeras 12 semanas del programa. Conclusión. El programa controlado de entrenamiento en el tapiz rodante durante 12 semanas mejoró SaO2, VO2max y la distancia máxima caminada de los participantes. Los valores medios de los participantes disminuyeron después de la semana 30 y 48 debido a la falta de adherencia al programa sin supervisión.Background. Physical activity is known to play an important role in improving the cardiopulmonary function and arterial blood oxygenation (SaO2) in elderly subjects. Objective. To evaluate the therapeutic efficacy of treadmill exercises on SaO2, maximum oxygen consumption (VO2max) and maximum walking distance in elderly healthy subjects. Design. Intervention study in El Salam General Hospitals, El Cairo (Egypt). Participants. Our study included 82 subjects (41subjects intervention group & 41 subjects control group) All participants appeared healthy, without chronic diseases and passed the Cardiopulmonary Exercise Test. Intervention. Participants were incorporated in a treadmill exercise program of moderate intensity to attain a fraction of 60% to 70% of the maximum heart rate. After 12 weeks of controlled physical activity, the program was made voluntarily for 36 weeks. Measurements. SaO2, VO2max and maximum walking distance were measured for each individual one-week before and 12 weeks after training and at the 30th and the 48th week of the program. Descriptive statistics: Mean, Standard deviation (± SD) and range for numerical data; Frequency and percentage of non-numerical data Analytical statistics: Student T Test, ANOVA, post hoc test, Chi-Square, paired t-test and linear regression (levels o significance: ns = p>.05; s= p<.05; hs = p<.01. Results. Our study included 82 subjects 41 the control group & the other 41 were the intervention one, each group consisted of 20 men and 21 women, with mean age of 65.1 + 2.7 years (range 60-69).In the in the intervention group there was an increase in the mean values of SaO2, VO2max and maximum walking distance after 12 weeks of controlled exercise and also at the 30th week and the 48th week of the program (p < 0.05). There has been a decrease in the mean values of VO2max, SaO2 and maximum walking distance after the 30th and 48th week in comparison with the values after the first 12 weeks. Conclusion. Controlled treadmill exercise for 12 weeks improved SaO2, VO2max and maximum walking distance of the participants. The mean values of the participants decreased after the 30th and 48th week due to lack of adherence to the unsupervised program

Enhancing Self-consumption of PV-battery Systems Using a Predictive Rule-based Energy Management

A predictive real-time Energy Management System (EMS) is proposed which improves PV self-consumption and operating costs using a novel rule-based battery scheduling algorithm. The proposed EMS uses the day-ahead demand and PV generation forecasting to determine the best battery scheduling for the next day. The proposed method optimizes the use of the battery storage and extends battery lifetime by only storing the required energy by considering the forecasted day-ahead energy at peak time. The proposed EMS has been implemented in MATLAB software and using Active Office Building on the Swansea University campus as a case study. Results are compared favorably with published state-of-the-arts algorithms to demonstrate its effectiveness. Results show a saving of 20% and 41% in total energy cost over six months compared to a forecast-based EMS and to a conventional EMS, respectively. Furthermore, a reduction of 54% in the net energy exchanged with the utility by avoiding the unnecessary charge/discharge cycles

Investigation of Electric Vehicles Contributions in an Optimized Peer-to-Peer Energy Trading System

The rapid increase in integration of Electric Vehicles (EVs) and Renewable Energy Sources (RESs) at the consumption level poses many challenges for network operators. Recently, Peer-to-Peer (P2P) energy trading has been considered as an effective approach for managing RESs, EVs, and providing market solutions. This paper investigates the effect of EVs and shiftable loads on P2P energy trading with enhanced Vehicle to Home (V2H) mode, and proposes an optimized Energy Management Systems aimed to reduce the net energy exchange with the grid. Mixed-integer linear programming (MILP) is used to find optimal energy scheduling for smart houses in a community. Results show that the V2H mode reduces the overall energy costs of each prosumer by up to 23% compared to operating without V2H mode (i.e., EVs act as a load only). It also reduces the overall energy costs of the community by 15% compared to the houses operating without the V2H mode. Moreover, it reduces the absolute net energy exchanged between the community and the grid by 3%, which enhances the energy independence of the community