51 research outputs found
Advancement of a modular rotor permanent magnet flux switching machine for high torque performance
Usage of electric motors in electric vehicle applications have gained a lot of attention since the motor must possessed high torque density and power. Permanent magnet flux switching machines have attracted considerable interests in recent years since the flux focusing is utilizable, both armature windings and PM excitation sources are on the stator, and the salient pole rotor is simple yet robust. Regrettably, salient rotor and stator of PMFSM with single tooth winding have inherited flux cancellation, flux leakage, high iron losses, high winding losses, and longer flux paths which reduced the torque and efficiency of the motor. In this thesis, a flux switching motor using permanent magnet employing modular rotor is designed and investigated for high torque making it suitable for high torque performances applications. The design engaged a three-phase 12 stator tooth taking up four sets of windings per phase with 10 pole feasible modular rotor. The characteristics performance of modular rotor PMFSM were designed and analysed using JMAG designer 14.1 utilizing 2D finite element analysis (2D-FEA). The initial 12S/10P modular rotor PMFSM topology achieved an average torque of 34.44 Nm with an output power of 5.67 kW. To further improve the performance of modular rotor PMFSM, local optimization approach was conducted which achieved an average torque of 60.49Nm and an output power of 23.34 kW while maintaining the same motor’s outer diameter. Furthermore, to compare modular rotor PMFSM with salient rotor PMFSM, FEFSM and HEFSM were utilized to choose best candidate for high torque performance. In comparison, optimized modular rotor PMFSM generated the highest output torque followed by optimized salient rotor HEFSM which generated the second highest torque. Consequently, the modular rotor PMFSM produced higher average torque, less iron losses, less weight and shorten flux path than using salient rotor pole PMFSM, FEFSM or HEFSM. In conclusion, modular rotor PMFSM confirms good agreement with high torque applications
One-pot synthesis of crystalline structure: Nickel-iron phosphide and selenide for hydrogen production in alkaline water splitting
Electrocatalytically active nanocomposites play a vital role in energy generation, conversion, and storage technologies. Transition metal-based catalysts such as nickel and iron and their pnictide (phosphide), and chalcogenide (selenide) compounds exhibit good activity for hydrogen evolution reaction (HER) in the alkaline environment. In this study, transition metals-based catalysts (Ni-P-Se, Fe-P-Se, and Ni-Fe-P-Se) solutions were prepared using a simple one-pot method. Prepared solutions were deposited on Ni foam, and different characterization techniques were used to determine the composition, structure, and morphology of as-prepared catalysts. Furthermore, it was found that Ni-Fe-P-Se as a cathode material showed better HER performance compared to other investigated materials with the overpotential value of 316 mV at 10 mA cm-2 current density and 89 mV dec-1 Tafel slope value. The stability tests of the as-prepared catalyst confirmed that the synergistic effect between various elements enhances the electrocatalytic performance for up to 24 hours, providing a fair, stable nature of Ni-Fe-P-Se based sample
Preliminary Study On Yoke Sizing Of Concentric Magnetic Gear
In this paper, torque, torque density, efficiency and efficiency slope of concentric magnetic gear (CMG) at different yoke sizes are evaluated using 2D finite element. Transient analysis when eddy current loss included and excluded are simulated. Efficiency to speed o used in this study is similar to the original gear ratio, 5.5. The change in the yoke size also effect the torque density of the CMG. The finding showed that the change in size at the outer rotor yoke influence the torque and efficiency the most. The smallest outer rotor yoke yields higher torque density of 55% then the average value in this study and slower gear efficiency degradatio
Dual-Branch U-Net Architecture for Retinal Lesions Segmentation on Fundus Image
Deep learning has found widespread application in diabetic retinopathy (DR) screening, primarily for lesion detection. However, this approach encounters challenges such as information loss due to convolutional operations, shape uncertainty, and the high similarity between different lesions types. These factors collectively hinder the accurate segmentation of lesions. In this research paper, we introduce a novel dual-branch U-Net architecture, referred to as Dual-Branch (DB)-U-Net, tailored to address the intricacies of small-scale lesion segmentation. Our approach involves two branches: one employs a U-Net to capture the shared characteristics of lesions, while the other utilizes a modified U-Net, known as U2Net, equipped with two decoders that share a common encoder. U2Net is responsible for generating probability maps for lesion segmentation as well as corresponding boundary segmentation. DB U-Net combines the outputs of U2Net and U-Net as a dual branch, concatenating their segmentation maps to produce the final result. To mitigate the challenge of imbalanced data, we employ the Dice loss as a loss function. We evaluate the effectiveness of our approach on publicly available datasets, including DDR, IDRiD, and E-Ophtha. Our results demonstrate that DB U-Net achieves AUPR values of 0.5254 and 0.7297 for Microaneurysms and soft exudates segmentation, respectively, on the IDRiD dataset. These results outperform other models, highlighting the potential clinical utility of our method in identifying retinal lesions from retinal fundus images
Factors That Influence Travelers’ Willingness to Adopt Bus Rapid Transit (Green Line) Service in Karachi
peer reviewedBus rapid transit (BRT) system is a sustainable mode choice alternative and traffic management method for traffic congestion problems in urban areas. As an extent of total demand management, BRT has broadly been implemented in many countries. BRT has proven to be progressive in alleviating traffic congestion and the difficulty of finding parking spaces in city centers. Currently, people driving their automobiles to work cause traffic congestion along Karachi’s main corridors. People cannot be persuaded to use public transit until their travel patterns are understood. Therefore, the disparity between public and private transportation must be addressed. This research aimed to develop a model to shift car travelers toward Karachi’s Green Line BRT and investigate the factors that influence car travelers’ decisions. A questionnaire-based survey was carried out on single-occupant vehicle (SOV) users in the Green Line corridor of Karachi. This study investigated the elements that influence SOV users’ willingness to adopt the BRT system and studied the possible ways of attracting car drivers to BRT. Data were examined using descriptive-analytic techniques such as the contingency table approach in conjunction with a Chi-square test of the independence/association model in SPSS. Furthermore, binary logistic regression was applied to the highly mediated associated variables. The research’s outcomes were geared at the imposition of parking fees at workplaces to deter individuals from parking their automobiles there. SOV travelers can be diverted to BRT services using this strategy. The research findings will assist policymakers and serve as a foundation for scientific investigations on the travel demand model for the BRT system.11. Sustainable cities and communitie
Preliminary selection and evaluation of fungicides and natural compounds to control grey mold disease of rose caused by Botrytis cinerea
Botrytis cinerea es un hongo patógeno de las plantas que causa la enfermedad del moho gris del rosal (Rosa indica L.). La búsqueda de estrategias de control nuevas y alternativas respetuosas con el medio ambiente, en lugar de los productos químicos peligrosos, para diferentes enfermedades de los cultivos es un paso crucial y saludable para hacer frente a los retos actuales del cambio climático. Por lo tanto, este estudio tuvo como objetivo evaluar la eficacia de diferentes extractos botánicos y agentes de biocontrol (biopesticidas) junto con diferentes fungicidas contra B. cinerea en condiciones in vitro. Se utilizaron tres concentraciones diferentes, a saber, 100, 200 y 300 ppm de cinco fungicidas, a saber, Acrobate, Melody, Cabrio top, Antracol y oxicloruro de cobre, extractos botánicos de ocho plantas Dhatura, Jengibre, Aak, Neem y Cebolla, en tres dosis diferentes de 5, 10 y 15%, El estudio de la incidencia de la enfermedad% de moho gris en el cultivo de rosas en la región muestra que la región de Hyderabad tiene un máximo (60%) de incidencia de la enfermedad en comparación con la región de Tandojam (40%). Entre los fungicidas, el Cabrio top redujo significativamente el crecimiento lineal de colonias (31 mm) de B. cinerea a una concentración de 300 ppm. Entre los productos botánicos, el extracto de la planta de neem mostró significativamente el menor crecimiento de colonias (23,33 mm), seguido de la planta de jengibre (25 mm) y la planta de dhatura (26 mm). La mayor concentración de fungicidas y las dosis más altas (15%) de extractos botánicos resultaron significativamente eficaces para controlar el patógeno B. cinerea. Among biopesticides, Fusarium solani appeared prominent in reducing colony growth (25.16 mm) of the pathogen but the difference was not significant 300 with most of the tested biocontrol agents. La recomendación en este estudio es la alta capacidad de los extractos botánicos y agentes de biocontrol en la reducción del crecimiento de moho gris, considerando potencialmente su uso en lugar de fungicidas sintéticos y mayor seguridad para el ecosistema.Campus Ic
Effects of a high-dose 24-h infusion of tranexamic acid on death and thromboembolic events in patients with acute gastrointestinal bleeding (HALT-IT): an international randomised, double-blind, placebo-controlled trial
Background: Tranexamic acid reduces surgical bleeding and reduces death due to bleeding in patients with trauma.
Meta-analyses of small trials show that tranexamic acid might decrease deaths from gastrointestinal bleeding. We
aimed to assess the effects of tranexamic acid in patients with gastrointestinal bleeding.
Methods: We did an international, multicentre, randomised, placebo-controlled trial in 164 hospitals in 15 countries.
Patients were enrolled if the responsible clinician was uncertain whether to use tranexamic acid, were aged above the
minimum age considered an adult in their country (either aged 16 years and older or aged 18 years and older), and
had significant (defined as at risk of bleeding to death) upper or lower gastrointestinal bleeding. Patients were
randomly assigned by selection of a numbered treatment pack from a box containing eight packs that were identical
apart from the pack number. Patients received either a loading dose of 1 g tranexamic acid, which was added to
100 mL infusion bag of 0·9% sodium chloride and infused by slow intravenous injection over 10 min, followed by a
maintenance dose of 3 g tranexamic acid added to 1 L of any isotonic intravenous solution and infused at 125 mg/h
for 24 h, or placebo (sodium chloride 0·9%). Patients, caregivers, and those assessing outcomes were masked to
allocation. The primary outcome was death due to bleeding within 5 days of randomisation; analysis excluded patients
who received neither dose of the allocated treatment and those for whom outcome data on death were unavailable.
This trial was registered with Current Controlled Trials, ISRCTN11225767, and ClinicalTrials.gov, NCT01658124.
Findings: Between July 4, 2013, and June 21, 2019, we randomly allocated 12 009 patients to receive tranexamic acid
(5994, 49·9%) or matching placebo (6015, 50·1%), of whom 11 952 (99·5%) received the first dose of the allocated
treatment. Death due to bleeding within 5 days of randomisation occurred in 222 (4%) of 5956 patients in the
tranexamic acid group and in 226 (4%) of 5981 patients in the placebo group (risk ratio [RR] 0·99, 95% CI 0·82–1·18).
Arterial thromboembolic events (myocardial infarction or stroke) were similar in the tranexamic acid group and
placebo group (42 [0·7%] of 5952 vs 46 [0·8%] of 5977; 0·92; 0·60 to 1·39). Venous thromboembolic events (deep vein
thrombosis or pulmonary embolism) were higher in tranexamic acid group than in the placebo group (48 [0·8%] of
5952 vs 26 [0·4%] of 5977; RR 1·85; 95% CI 1·15 to 2·98).
Interpretation: We found that tranexamic acid did not reduce death from gastrointestinal bleeding. On the basis of our
results, tranexamic acid should not be used for the treatment of gastrointestinal bleeding outside the context of a
randomised trial
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