328 research outputs found
Parallel Distributed Compensation-PID Controller Design for Maximum Power Point Tracking of Dynamic Loaded Photovoltaic System
Control issues come from the output voltage of PV installations and systems operating in a range of irradiance and temperature. By using a DC converter, such systems are able to maintain a constant output voltage despite fluctuations in the generated voltage and load. The design of a maximum power point tracking (MPPT) on DC converter controller is presented in this article for a system. Fractional Order-Proportional Integral Derivative (FO-PID) and Parallel Distributed Compensation-Proportional Integral Derivative (PDC-PID) controllers have been implemented to the system converter as a proposed control approach. Particle Swarm Optimization (PSO) is used as optimization technique for determining the optimal parameters of (FO-PID) and (PDC-PID) controllers for tracking the output voltage from trained Adaptive Neuro Fuzzy Inference System (ANFIS) that is corresponding to maximum power generated from (PV) module. The PV system with the dynamic load is modeled and simulated by using the MATLAB/Simulink environment. The system performance is displayed in the form of a family of curves under different operating conditions
A Novel 3D Evaluation of the Correlation Between the Condylar Position and Angle Classification in a Lebanese Population: A Pilot Study
Résumé
Introduction : L’articulation temporo-mandibulaire (ATM) est l’une des articulations les plus complexes. Sa morphologie varie selon les individus, et même entre les côtés gauche et droit. Plusieurs études ont démontré une relation significative entre certaines caractéristiques occlusales et la morphologie articulaire. La tomodensitométrie à faisceau conique (CBCT) est actuellement la modalité la plus largement adoptée pour l’examen de l’ATM.
Objectif : Cette étude vise à comparer, dans une cohorte Libanaise, l’espace interarticulaire avec les différentes classes d’Angle en utilisant le CBCT.
Méthodologie : Une analyse rétrospective a été menée sur des images CBCT réalisées à l’Université Saint Joseph de Beyrouth sur une période de 1 an, entre 2021 et 2022. Quatre valeurs de clairance ont été sélectionnées, représentant la distance minimale entre l’os temporal et le condyle mandibulaire qui définit l’espace interarticulaire : 0,5 mm, 1 mm, 1,5 mm et 2 mm. Pour chaque valeur choisie, nous avons recherché la présence ou non d’une surface visible. Cette surface correspond à la zone du condyle ayant une distance du condyle à l’os temporal inférieure ou égale à la valeur choisie.
Résultats : Vingt-neuf patients âgés de 12 à 60 ans ont été inclus ; 12 (41 %) étaient des hommes et 17 (59 %) des femmes. Les 48 images CBCT (23 du côté droit et 25 du côté gauche) ont été réparties en trois groupes selon la classification d’Angle : classe I (n = 14), classe II (n = 29) et classe III (n = 5). Pour une distance de [0 mm ;0,5 mm ;1mm et 1,5mm] correspondent des surfaces de valeurs nulles. Pour un intervalle compris entre [1,5 – 2mm] correspond une surface de 18,8 mm2 pour les sujets de classe I, 16,6 mm2 pour les sujets de classe II, et 30,5 mm2 pour les sujets de classe III. Les résultats n’ont pas montré de corrélation statistiquement significative entre l’espace interarticulaire et les différentes classes d’Angle.
Conclusion : L’évaluation tridimensionnelle de la position condylienne par CBCT a montré qu’il n’existe pas de corrélation entre les espaces interarticulaires et les différentes classes d’Angle.
Mots clés : position condylienne ; classification d’Angle ; occlusion ; CBCT ; tomodensitométrie.
Abstract
Introduction: The temporomandibular joint (TMJ) is one of the most complex joints. Its morphology varies between individuals, and even between the left and right sides. Several studies have found a significant relation between certain occlusal features and joint morphology. Cone-beam computed tomography (CBCT) imaging is currently the most widely adopted modality for the examination of the TMJ.
Objective: This study aimed to compare the joint space in a Lebanese cohort with different Angle classification using CBCT.
Methodology: We retrospectively analyzed CBCT images performed at the Saint Joseph University of Beirut in Lebanon, over a period of 1 year, between 2021 and 2022. Four clearance values were selected, representing the minimum distance between the temporal bone and the mandibular condyle that defines the joint space: 0.5 mm, 1 mm, 1.5 mm, and 2 mm. For each value chosen, we looked for the presence or not of a visible surface. This surface corresponds to the area of the condyle with a distance from the condyle to the temporal bone less than or equal to the chosen value.
Results: Twenty-nine patients aged between 12 and 60 years old were included; 12 (41%) were males and 17 (59%) females. We classified 48 CBCT images (23 on the right side and 25 on the left side) into three groups according to Angle’s classification: class I (n=14), class II (n=29), and class III (n=5). For a distance of [0-1.5 mm] corresponded a surface of 0 mm2. For the interval between [1.5-2 mm] corresponded a surface of 18,8 mm2 for class I subjects, 16,6 mm2 for class II, and 30,5 mm2 for class III. The results showed no statistically significant differences between the articular spaces and the different types of occlusion.
Conclusion: The three-dimensional evaluation of the condylar position by CBCT showed that there are no significant differences between the joint spaces and the different types of occlusion according to Angle’s classification.
Keywords: condylar position; Angle classification; occlusion; CBCT
Relative Rate Observer Self-Tuning of Fuzzy PID Virtual Inertia Control for An Islanded microgrid
Expanding the usage of renewable energy in islanded microgrids leads to a reduction in its total inertia. Low inertia microgrids have difficulties in voltage and frequency control. That affected saving its stability and preventing a blackout. To improve low inertia islanded microgrids\u27 dynamic response and save their stability, this paper presented relative rate observer self-tuning fuzzy PID (RROSTF-PID) based on virtual inertia control (VIC) for an islanded microgrid with a high renewable energy sources (RESs) contribution. RROSTF-PID based on VIC\u27s success in showing remarkable improvement in the microgrid\u27s dynamic response and enhancement of its stability. Moreover, it handles different contingency conditions successfully by giving the desired frequency support. Ant colony optimization (ACO) technique is used to find the optimal values of the RROSTF-PID based on VIC parameters. Furthermore, using MATLAB TM/Simulink, RROSTF-PID based on VIC response is compared to Optimal Fuzzy PID (OF-PID) based VIC, Fuzzy PID (F-PID) based VIC, PID-based VIC, conventional VIC responses, and the microgrid without VIC response under different operation conditions
Transvenous Lead Extraction of Cardiac Implantable Electronic Devices Indications, Complications and Outcome: An Egyptian Two Years' Experience
BACKGROUND: The growing needs to extract cardiovascular implantable electronic devices warrants the need to improve the outcome and prevent complications.
AIM: This study aims to analyse the findings and identify factors associated with complications of Percutaneous Transvenous Lead Extraction in the Critical Care Department, Cairo University.
METHODS: We studied 52 candidates for Percutaneous Transvenous Lead extraction of a Permanent Pace Maker (PPM) regarding extraction indications, comorbidities, device type, complications and outcome. Extraction was first attempted by simple manual traction using regular non-locking stylet and if failed, locking stylet, and evolution dilator sheath were used.
RESULTS: We extracted 110 leads with a mean lead age of 4.67 ± 3.6 years. The most common extraction indication was an infection (71.15%). Indications correlated significantly with comorbidities (p = 0.024), the most common being Diabetes Mellitus (40.38%). Simple traction was successful in 31 % of the leads, while 69% were extracted using locking stylet and evolution dilator sheath. The method of lead extraction correlated significantly with lead age (P ≤ 0.001). Complications were significantly higher with extraction by evolution dilator sheaths than by simple traction (P = 0.003) and in older patients (P = 0.008). Complications also correlated significantly with extractions indications (p = 0.012), type of PPM (P = 0.037), number of extracted leads (P = 0.041), and lead age (p= 0.011).
CONCLUSION: Among the studied variables, extraction indications particularly infection, was the only preventable factor significantly associated with complications. While focusing on preventable factors, improving, implantation and extraction techniques should also be addressed
Isolation of avian influenza H5N1 virus from vaccinated commercial layer flock in Egypt
Uninterrupted transmission of highly pathogenic avian influenza virus (HPAIV)
H5N1 of clade 2.2.1 in Egypt since 2006 resulted in establishment of two main
genetic clusters. The 2.2.1/C group where all recent human and majority of
backyard origin viruses clustered together, meanwhile the majority of viruses
derived from vaccinated poultry in commercial farms grouped in 2.2.1.1 clade.
In the present investigation, an HPAIV H5N1 was isolated from twenty weeks old
layers chickens that were vaccinated with a homologous H5N1 vaccine at 1, 7
and 16 weeks old. At twenty weeks of age, birds showed cyanosis of comb and
wattle, decrease in egg production and up to 27% mortality. Examined serum
samples showed low antibody titer in HI test (Log2 3.2 ± 4.2). The
hemagglutinin (HA) and neuraminidase (NA) genes of the isolated virus were
closely related to viruses in 2.2.1/C group isolated from poultry in live bird
market (LBM) and backyards or from infected people. Conspicuous mutations in
the HA and NA genes including a deletion within the receptor binding domain in
the HA globular head region were observed. Despite repeated vaccination of
layer chickens using a homologous H5N1 vaccine, infection with HPAIV H5N1
resulted in significant morbidity and mortality. In endemic countries like
Egypt, rigorous control measures including enforcement of biosecurity, culling
of infected birds and constant update of vaccine virus strains are highly
required to prevent circulation of HPAIV H5N1 between backyard birds,
commercial poultry, LBM and humans
Insights into primary care physicians’ detection, intervention and management of patients with substance use disorders in Egypt
Egypt is experiencing an increasing drug problem (cannabis, heroin, amphetamines, pharmaceutical opioids, synthetic cannabinoids). Whilst harm reduction and addiction treatment are provided by government and non-governmental organisations in Egypt, very little is known about physicians experience of handling patient substance use and substance use disorder (SUD) in primary care. A cross-sectional national study of 392 Egyptian Family Physicians (FPs) & General Practitioners (GPs) explored their knowledge, attitude and professional practice regarding management of SUD in primary care, as a first step towards identifying professional development support needs and informing general practice. Findings underscore the need for greater depth of addiction training during undergraduate medical education and in continuing professional development, so that Egyptian FPs/GPs can better prevent harmful substance use, detect patients with SUD, intervene and support those in treatment. This study provides unique information which will inform further development and scale of evidence based SUD brief intervention and treatment within Egyptian primary car
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
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