27 research outputs found

    Genetic characterization of human echinococcosis in Southern Punjab, Pakistan

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    IntroductionEchinococcosis is a neglected tropical zoonotic infection that affects both the human and livestock populations. In Pakistan, the infection is long-standing, but data on its molecular epidemiology and genotypic characterization in the southern Punjab region are limited. The aim of the current study was the molecular characterization of human echinococcosis in southern Punjab, Pakistan.MethodsEchinococcal cysts were obtained from a total of 28 surgically treated patients. Patients’ demographic characteristics were also recorded. The cyst samples were subjected to further processing to isolate DNA in order to probe the Nad1 and Cyt-b genes, followed by DNA sequencing and phylogenetic analysis for genotypic identification.ResultsThe majority of the echinococcal cysts were from male patients (60.7%). The liver was the most commonly infected organ (60.71%), followed by the lungs (25%), spleen (7.14%), and the mesentery (7.14%). Molecular and genotypic identification through sequencing and phylogenetic tree analysis showed that most of the cysts (24/28, 85.7%) were caused by the species Echinococcus granulosus sensu stricto (E. granulosus s.s.) (G1 and G3), followed by Echinococcus multilocularis (E. multilocularis) and Echinococcus canadensis (E. canadensis) (G6/G7) (3/28, 10.8%, and 1/28, 3.5%, respectively).ConclusionThe current study concluded that the majority of human infections were caused by E. granulosus s.s., followed by the E. multilocularis and E. canadensis species (G6/G7). Genotypic characterization among both human and livestock populations is needed to explore the genetic diversity of echinococcosis

    Design and Thermal Modeling of Modular Hybrid Excited Double-Sided Linear Flux Switching Machine

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    This paper presents a Hybrid Excited Double-Sided Linear Flux Switching Machine (HEDSLFSM) with a crooked tooth modular stator. Generally, the conventional stators are made of a full-length iron core, increasing manufacturing costs and iron losses. Higher iron losses result in lower efficiency and lower overall performance. A U-shaped modular stator with a crooked tooth is used to lower iron consumption and increase the machine’s efficiency. Ferrite magnets are used to replace rare earth magnets, which also reduces the machine cost. Two DC excitation windings are used above and below the ferrite magnet to reduce the PM volume. 2D electromagnetic performance analysis is done to observe the key performance indices. Geometric optimization is used to optimize the Split Ratio (S.R), DC winding slot area (DCw), and AC winding slot area (ACw). Stator Tooth Width (STW), space between the modules (S.S.), and crooked angle (α) are optimized through JMAG in-built Genetic Algorithm (G.A.) optimization. High thrust force density and modular stator make it a good candidate for long-stroke applications like railway transits. The thermal analysis of the machine is performed by FEA analysis and then validated by 2D LPMC (Lumped Parametric Magnetic Equivalent Circuit) model. Both analyses are compared, and an error percentage of less than 4% is achieved

    Design and Thermal Modeling of Modular Hybrid Excited Double-Sided Linear Flux Switching Machine

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    This paper presents a Hybrid Excited Double-Sided Linear Flux Switching Machine (HEDSLFSM) with a crooked tooth modular stator. Generally, the conventional stators are made of a full-length iron core, increasing manufacturing costs and iron losses. Higher iron losses result in lower efficiency and lower overall performance. A U-shaped modular stator with a crooked tooth is used to lower iron consumption and increase the machine’s efficiency. Ferrite magnets are used to replace rare earth magnets, which also reduces the machine cost. Two DC excitation windings are used above and below the ferrite magnet to reduce the PM volume. 2D electromagnetic performance analysis is done to observe the key performance indices. Geometric optimization is used to optimize the Split Ratio (S.R), DC winding slot area (DCw), and AC winding slot area (ACw). Stator Tooth Width (STW), space between the modules (S.S.), and crooked angle (α) are optimized through JMAG in-built Genetic Algorithm (G.A.) optimization. High thrust force density and modular stator make it a good candidate for long-stroke applications like railway transits. The thermal analysis of the machine is performed by FEA analysis and then validated by 2D LPMC (Lumped Parametric Magnetic Equivalent Circuit) model. Both analyses are compared, and an error percentage of less than 4% is achieved

    Performance Analysis and Optimization of a Novel Outer Rotor Field-Excited Flux-Switching Machine with Combined Semi-Closed and Open Slots Stator

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    Slotting effect in electric machines reduces flux per pole that effect magnetic flux density distribution in the air gap which induces harmonics in magnetic flux density causing flux pulsation, that in turn generates dominant torque pulsation in the form of cogging torque and torque ripples. To overcome the abovesaid demerits, a novel outer rotor field-excited flux-switching machine (OR-FSFSM) with a combined semi-closed and open slots stator is proposed in this study. The developed OR-FEFSM offers a high-power factor, due to the utilization of the semi-closed slot for armature coils. The open slot stator structure was chosen for the field excitation coil, which effectively suppresses leakage reluctance that causes flux pulsation. Thus, the influence of torque ripples is reduced, and the average torque is improved. In order to investigate the effectiveness of the proposed OR-FEFSM, a detailed study of stator slot and rotor pole combinations are performed. Based on simplified mathematical formulation, 12S/7P (stator slot/rotor poles), 12S/11P, 12S/13P, and 12S/17P are the most feasible combinations. Finite Element Analysis (FEA) based on comprehensive electromagnetic performance is performed on each combination, and found that 12S/13P offers the highest average torque of 4.62 Nm, whereas 3.72 Nm, 2.72Nm, and 1.68 Nm average torque is offered by 12S/17P, 12S/7P, and 12S/11P, respectively. Based on the initial analysis, 12S/13P was considered for further analysis and optimized using JMAG built-in Genetic Algorithm (GA). Moreover, thermal analysis was performed, and the proposed design was compared with the conventional design

    Design and Analysis of an Asymmetric Spoke and Delta-Shape Interior Permanent Magnet Synchronous Machine

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    This paper proposes a design of an asymmetric spoke and delta-shape interior permanent magnet (AIPM-P) synchronous machine for electric vehicles that use the magnetic-field-shifting (MFS) technique to improve the average torque and reduce torque ripples. The asymmetry of the AIPM-P is due to the asymmetric rotor structure, asymmetric permanent magnet (PM) placement, and asymmetric flux barriers (AFB). Due to this asymmetry, the MFS is utilized, which decreases the current angle difference between the peak PM torque ( TPMT_{PM} ) and reluctance torque ( TrT_{r} ) components. In the delta-shape, the bar magnet helps reduce the d-axis inductance, which helps in increasing the reluctance torque, ultimately increasing synthetic torque. Furthermore, the combination of delta-shape and spoke shape PM makes the novel hybrid layer structure that improves the average torque. The proposed AIPM-P is then compared with the conventional designs in the literature having the same stator and rotor radius, with a 4-pole and 24-slot combination. The open circuit, on-load characteristics, efficiency, copper, and iron loss maps of the proposed and conventional designs are investigated and compared. Compared to the conventional designs, the proposed AIPM-P synchronous machine has high efficiency and a good torque profile, which is suitable for EV applications

    Design and Thermal Analysis of Linear Hybrid Excited Flux Switching Machine Using Ferrite Magnets

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    This paper presents a novel linear hybrid excited flux switching permanent magnet machine (LHEFSPMM) with a crooked tooth modular stator. Conventional stators are made up of a pure iron core, which results in high manufacturing costs and increased iron core losses. Using a modular stator lowers the iron volume by up to 18% compared to a conventional stator, which minimizes the core losses and reduces the machine’s overall cost. A crooked angle is introduced to improve the flux linkage between the stator pole and the mover slot. Ferrite magnets are used with parallel magnetization to reduce the cost of the machine. Two-dimensional FEA is performed to analyze and evaluate various performance parameters of the proposed machine. Geometric optimization is used to optimize the split ratio (S.R) and winding slot area (Slotarea). Genetic algorithm (GA) is applied and is used to optimize stator tooth width (STW), space between the modules (SS), crooked angle (α), and starting angle (θ). The proposed model has a high thrust density (306.61 kN/m3), lower detent force (8.4 N), and a simpler design with higher efficiency (86%). The linear modular structure makes it a good candidate for railway transportation and electric trains. Thermal analysis of the machine is performed by FEA and then the results are validated by an LPMEC model. Overall, a very good agreement is observed between both the analyses, and relative percentage error of less than 3% is achieved, which is considerable since the FEA is in 3D while 2D temperature flow is considered in the LPMEC model
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