814 research outputs found

    Modeling and control of a voltage-lift cell split-source inverter with MPPT for photovoltaic systems

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    In this study, a new single-stage inverter with improved boosting performance was proposed to enhance the recently developed split-source inverter (SSI) topology. The study introduced new SSI configurations with high voltage gain. The proposed design features a voltage-lift cell made of capacitors, inductors, and diodes, which increases the boosting capability. The decoupled control technique, where The DC input current is controlled by the AC modulation signals,allows for independent adjustment of both the DC input and AC output current. The research also employed a modified space vector modulation approach to manage the inverter switches and reduce current ripple. The combination of the proposed topology and the modified SVPWM scheme significantly improves the DC-boosting capabilities. the validity of the proposed solution was confirmed through simulation using three-phase SSI models in MATLAB/SIMULINK®. Finally, The validity of the simulation and experimental investigation of the analysis and performance of the topologies provided

    Computational fluid dynamics simulation on the heat sink performance of a graphics processing unit thermal management

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    The article focuses on the numerical investigation of temperature distribution in a central processing units (CPU) case with different time interval such as t = 100 s, 200 s, 300 s, 400 s, 500 s. Heat sink performance of a graphics processing unit (GPU) thermal management and impacts of different shape and velocity on the thermal performance are considered. In this study, three heat sink models are designed (A, B, and C) based on the volume area of heat sink. This study emphasizes the heat transfer phenomena caused by a GPU in a computer case in both steady state and transient state. A CFD software STAR – CCM + is used to carry out to study the fluid flow and heat transfer simulation of graphics card heat sink in a computer case and the same time an enhanced method of reducing the temperature of GPU is proposed. The results show that heat sink B with the least volume area, has the fastest rate of heat exchange followed by heat sink C and heat sink A. Likewise, the result indicates an inverse relationship between the volume and the total surface of the heat sink and the final temperature of the graphics card chip. As the total volume and surface of the heat sink increases, the rate of heat transfer increases via faster rate of conduction between graphics card chip to heat sink meanwhile the cooling of the heat sink is aided by wind inlet via convection

    Basin Analysis of the Late Cretaceous Sediments in United Arab Emirates

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    Abstract: The Late Cretaceous Simsima Formation has been proved to be one of the most prolific reservoirs in the Arabian Basin, but still needs more investigations to be ultimately exploited.This promising formation has been subjected to a comprehensive study by various geologic disciplines to build up an adequate basin model for such formation. The study revealed that the Late Cretaceous Simsima Formation could be classified into two facies. These are Planktonic Foraminiferal Biomicrite (open marine source rock facies outcropped at Jabal Qarn El-Barr); and Rudistids Algal Foraminiferal Biomicrite (shallow marine reservoir rock facies exposed at Jabal Buhays and Jabal Malaqet) facies. This facies distribution indicates that the Late Cretaceous sea deepened towards the NNW of UAE ( Jabal Qarn El-Barr section). X-Ray diffraction analysis ensured the occurrence of open marine minerals (kaolinite and montmorillonite) within the Late Cretaceous Simsima Formation that outcropped at Jabal Qarn El-Barr. So, the Late Cretaceous Simsima Formation could act as an effective source rock (newly approved) in the northern part of UAE and a prolific reservoir rock in the other parts of UAE. The geochemical analyses also supported the occurrence of source rock facies (high TOC varies from 0.4 to 1.3 wt% and low Pr/Ph ratio) within the Late Cretaceous Simsima Formation. The petrophysical and petrographical investigations proved intercrystalline, vuggy and fracture porosity (varies from 0 to 31%) and permeability ranges from 0 to 850 md for the reservoir facies of Late Cretaceous Simsima Formation. Moreover, the occurrence of anticlinal and thrusted structures (almost acting as sealing faults) within the fractured limestones of the Late Cretaceous Simsima Formation would enhance the probability for hydrocarbon entrapment within these rocks

    Low-cost hardware in the loop for intelligent neural predictive control of hybrid electric vehicle

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    The design and investigation of an intelligent controller for hardware-in-the-loop (HIL) implementation of hybrid electric vehicles (HEVs) are proposed in this article. The proposed intelligent controller is adopted based on the enhancement of a model predictive controller (MPC) by an artificial neural network (ANN) approach. The MPC-based ANN (NNMPC) is proposed to control the speed of HEVs for a simulation system model and experimental HIL test systems. The HIL is established to assess the performance of the NNMPC to control the velocity of HEVs in an experimental environment. The real-time environment of HIL is implemented through a low-cost approach such as the integration of an Arduino Mega 2560 and a host Lenovo PC with a Core i7 @ 3.4 GHz processor. The NNMPC is compared with a proportional–integral (PI) controller, a classical MPC, and two different settings of the ANN methodology to verify the efficiency of the proposed intelligent NNMPC. The obtained results show a distinct behavior of the proposed NNMPC to control the speed of HEVs with good performance based on the distinct transient response, minimum error steady state, and system robustness against parameter perturbation

    Consensus evidence-based recommendations for treat-to-target management of immunoglobulin A vasculitis

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    IgA vasculitis (IgAV), formerly known as Henoch-Schönlein purpura, is the most common cause of systemic vasculitis in childhood. Given its potential life-threatening systemic complications, early and accurate diagnosis as well as management of IgAV represent a major challenge for health care professionals. This study was carried out to attain an evidence-based expert consensus on a treat-to-target management approach for IgAV using Delphi technique. The preliminary scientific committee identified a total of 16 key clinical questions according to the patient, intervention, comparison, and outcomes (PICO) approach. An evidence-based, systematic, literature review was conducted to compile evidence for the IgAV management. The core leadership team identified researchers and clinicians with expertise in IgAV management in Egypt upon which experts were gathered from different governorates and health centers across Egypt. Delphi process was implemented (two rounds) to reach a consensus. An online questionnaire was sent to expert panel (n = 26) who participated in the two rounds. After completing round 2, a total of 20 recommendation items, categorized into two sections were obtained. Agreement with the recommendations (rank 7–9) ranged from 91.7–100%. Consensus was reached (i.e. ⩾75% of respondents strongly agreed or agreed) on the wording of all the 20 clinical standards identified by the scientific committee. Algorithms for the diagnosis and management have been suggested. This was an expert, consensus recommendations for the diagnosis and treatment of IgAV and IgA vasculitic nephritis, based on best available evidence and expert opinion. The guideline presented a strategy of care with a pathway to achieve a state of remission as early as possible

    Congenital and childhood atrioventricular blocks: pathophysiology and contemporary management

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    Atrioventricular block is classified as congeni- tal if diagnosed in utero, at birth, or within the first month of life. The pathophysiological process is believed to be due to immune-mediated injury of the conduction system, which occurs as a result of transplacental pas- sage of maternal anti-SSA/Ro-SSB/La antibodies. Childhood atrioventricular block is therefore diagnosed between the first month and the 18th year of life. Genetic variants in multiple genes have been described to date in the pathogenesis of inherited progressive car- diac conduction disorders. Indications and techniques of cardiac pacing have also evolved to allow safe perma- nent cardiac pacing in almost all patients, including those with structural heart abnormalities

    A Portrait of the Transcriptome of the Neglected Trematode, Fasciola gigantica—Biological and Biotechnological Implications

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    Fasciola gigantica (Digenea) is an important foodborne trematode that causes liver fluke disease (fascioliasis) in mammals, including ungulates and humans, mainly in tropical climatic zones of the world. Despite its socioeconomic impact, almost nothing is known about the molecular biology of this parasite, its interplay with its hosts, and the pathogenesis of fascioliasis. Modern genomic technologies now provide unique opportunities to rapidly tackle these exciting areas. The present study reports the first transcriptome representing the adult stage of F. gigantica (of bovid origin), defined using a massively parallel sequencing-coupled bioinformatic approach. From >20 million raw sequence reads, >30,000 contiguous sequences were assembled, of which most were novel. Relative levels of transcription were determined for individual molecules, which were also characterized (at the inferred amino acid level) based on homology, gene ontology, and/or pathway mapping. Comparisons of the transcriptome of F. gigantica with those of other trematodes, including F. hepatica, revealed similarities in transcription for molecules inferred to have key roles in parasite-host interactions. Overall, the present dataset should provide a solid foundation for future fundamental genomic, proteomic, and metabolomic explorations of F. gigantica, as well as a basis for applied outcomes such as the development of novel methods of intervention against this neglected parasite

    Search for Resonant Production of High-Mass Photon Pairs in Proton-Proton Collisions at root s=8 and 13 TeV

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