993 research outputs found

    On Modulo AG-groupoids

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    A groupoid G is called an AG-groupoid if it satisfies the left invertive law: (ab)c = (cb)a. An AG-group G, is an AG-groupoid with left identity e \in G (that is, ea = a for all a \in G) and for all a \in G there exists a' \in G such that a.a' = a'.a = e. In this article we introduce the concept of AG-groupoids (mod n) and AG-group (mod n) using Vasantha's constructions [1]. This enables us to prove that AG-groupoids (mod n) and AG-groups (mod n) exist for every integer n \geq 3. We also give some nice characterizations of some classes of AG-groupoids in terms of AG-groupoids (mod n).Comment: 10 page

    PFC Topologies for AC to DC Converters in DC Micro-Grid

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    With increasing dominance of renewable energy resources and DC household appliances, the novelty of DC micro grid is attracting significant attention. The key interface between the main supply grid and DC micro grid is AC to DC converter. The conventional AC to DC converter with large output capacitor introduces undesirable power quality problems in the main supply current. It reduces system efficiency due to low power factor and high harmonic distortion. Power Factor Correction (PFC) circuits are used to make supply currents sinusoidal and in-phase with supply voltages. This paper presents different PFC topologies for single phase AC to DC converters which are analyzed for power factor (PF), total harmonic distortion (THD) and system efficiency by varying output power. Two-quadrant shunt active filter topology attains a power factor of 0.999, 3.03% THD and 98% system efficiency. Output voltage regulation of the presented active PFC topologies is simulated by applying a step load. Two-quadrant shunt active filter achieves better output voltage regulation compared to other topologies and can be used as grid interface

    Solid-state synthesis of nitrogen-doped graphitic nanotubes with outstanding electrochemical properties

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    peer-reviewedSynthesis of new anodes is crucial for commercialization of rechargeable potassium-ion batteries (PIBs). In this work, the nitrogen-doped graphitic nanotubes (NGTs) were synthesized by solid-state reaction method. The microstructural characterization of synthesized NGTs revealed the presence of many active sites (provided by N-doping i.e. Np and Ng) and tubular channels for the K+ ion transport. The NGTs electrode was tested against potassium metal in the presence of carbonate based electrolytes. The NGTs revealed the maximum reversible capacity of 220 mA h g 1 at 20 mA g 1 current density. Furthermore, the cycle stability of NGTs was confirmed by cycling it for 200 times at the current density of 100 mA g1, where specific capacity of 81.2 mA h g1 was retained. The excellent electrochemical properties (rate capability) and fast synthesis of NGTs highlights its possibility to be used against post-lithium metal anodes in near future Potassium-ion battery

    Cost Effective Bidirectional Power Transactions for Queueing Energy Requests in Smart Micro-Grids

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    This paper investigates real time problem of cost efficient energy distribution within smart micro-grids (SMG). The aggregator announces a day-ahead price of electricity, and is most often not fully aware of on spot availability of renewable resources. Sometimes, users also encounter estimation errors in their day-ahead energy procurement. In both situations an extra cost is incurred to aggregator or the users to fulfill their needs. This cost could be minimized by intelligently balancing the real time renewable generations with users load demands. The problem is more complex when there are a number of users communicating with each other and with the aggregator at the same time through a Digital Energy Management System (DEMS) for their demand requirements. It is very challenging for DEMS to ensure comfort level for its consumers while providing low cost electricity. Hence, we establish an optimization problem of curtailing the time average cost of electricity, under certain bounds of consumers satisfactions. We introduce load scheduling and energy transaction (LSET) control policy based on Lyapunov optimization theory to develop our proposed solution

    ROLE OF INTERLEUKIN-2, INTERLEUKIN-4 AND CLUSTER OF DIFFERENTIATION-22 AS AN IMMUNE MARKERS IN INDIVIDUALS INFECTED WITH Helicobacter pylori

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    Helicobacter pylori is a gram-negative, intracellular, microaerophilic bacteria which causing Peptic ulcer. This bacterium can change its shape which helps the bacteria to survive in the host gastric microenvironment. The Peptic ulcer caused by this bacterium stimulates the humoral and cellular immune response in individuals. The current study was carried out to access the role of interleukin-2, interleukin-4, and cluster differentiation-22 as immune markers in the identification of H. pylori infection. The presence of H. pylori has been diagnosed by feces test (antigen rapid test). In this study, the presence of three immunological markers viz., IL-2, IL-4, and CD22 were measured in the serum of 60 individuals infected with H. pylori and 30 healthy individuals by the Enzyme-Linked Immune-sorbent Assay method. Results of this study indicated a significant increase (P-value=0.0307*) in the concentration of IL-2 (294.27ng/ml), IL-4(151.28ng/ml), and CD22 (492.73ng/ml) in the serum of individuals infected with H. pylori while these concentrations were reported 235.98ng/ml, 116.14ng/ml and 369.33ng/ml respectively in the healthy individuals. Results of the study can be concluded that H.pylori infection stimulates the Cellular and humoral immune response which resulted in the increased production of IL-2, IL-4, and CD22
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