322 research outputs found

    Nonlinearity Induced Critical Coupling

    Full text link
    We study a critically coupled system (Opt. Lett., \textbf{32}, 1483 (2007)) with a Kerr-nonlinear spacer layer. Nonlinearity is shown to inhibit null-scattering in a critically coupled system at low powers. However, a system detuned from critical coupling can exhibit near-complete suppression of scattering by means of nonlinearity-induced changes in refractive index. Our studies reveal clearly an important aspect of critical coupling as a delicate balance in both the amplitude and the phase relations, while a nonlinear resonance in dispersive bistability concerns only the phase

    Power quality improvement in distribution system based on dynamic voltage restorer using PI tuned fuzzy logic controller

    Get PDF
    Purpose. This article proposes a new control strategy for Dynamic Voltage Restorer (DVR) in utility grid for distribution system. The proposed DVR using PI tuned fuzzy logic scheme is based on replacement of conventional DVR and voltage sag compensation in distribution system network. The novelty of the proposed work consists in presenting an enhanced PI tuned fuzzy logic algorithm to control efficiently the dynamic voltage restorer when voltage sag is suddenly occurred. Methods. The proposed algorithm which provides sophisticated and cost-effective solution for power quality problems. Our strategy is based on tuned fuzzy control of reactive powers and also closed loop for harmonic reduction in distribution system. The proposed control technique strategy is validated using MATLAB / Simulink software to analysis the working performances. Results. The results obtained clearly show that DVR using PI tuned fuzzy logic have good performances (sag compensation, harmonic reduction) compared to conventional DVR. Originality. Compensation of voltage sag/ swell in distribution for reactive power and current harmonic reduction by using DVR based PI tuned fuzzy logic controller. Practical value. The work concerns the comparative study and the application of DVR based on PI tuned fuzzy techniques to achieve a good performance control system of the distribution system. This article presents a comparative study between the conventional DVR control and PI tuned fuzzy DVR control. The strategy based on the use of a PI tuned fuzzy controller algorithm for the control of the continuous voltage sag and harmonic for the distribution network-linear as well as non-linear loads in efficient manner. The study is validated by the simulation results based on MATLAB / Simulink software.Мета. У статті пропонується нова стратегія управління пристроєм динамічного відновлення напруги (ДВН) в мережі розподільної системи. Запропонований ДВН, що використовує схему нечіткої логіки з ПІ-налаштуванням, заснований на заміні звичайного ДВН та компенсації провалів напруги в мережі розподільної системи. Новизна запропонованої роботи полягає у поданні удосконаленого алгоритму нечіткої логіки з ПІ-налаштуванням для ефективного управління динамічним відновником напруги при раптовому виникненні провалу напруги. Методи. Запропоновано алгоритм, який забезпечує складне та економічне вирішення проблем якості електроенергії. Наша стратегія заснована на нечіткому керуванні реактивною потужністю, що налаштовується, а також на замкненому контурі для зниження гармонік в розподільній системі. Запропонована методика управління перевіряється за допомогою програмного забезпечення MATLAB/Simulink для аналізу робочих характеристик. Результати. Отримані результати чітко показують, що ДВН, який використовує нечітку логіку з ПІ-налаштуванням, має хороші характеристики (компенсація провалів, зниження гармонік) порівняно із звичайним ДВН. Оригінальність. Компенсація провалів/стрибків напруги у розподільній мережі для зниження реактивної потужності та гармонік струму за допомогою нечіткої логіки з використанням ДВН на основі контролера нечіткої логіки з ПІ-налаштуванням. Практична цінність. Робота стосується порівняльного дослідження та застосування ДВН на основі нечіткої логіки з ПІ-налаштуванням для досягнення хороших параметрів системи керування розподільною системою. У статті представлено порівняльне дослідження звичайного керуванням ДВН та нечіткого керування ДВН з ПІ-налаштуванням. Стратегія, заснована на використанні алгоритму нечіткої логіки з ПІ-налаштуванням для ефективного керування безперервним провалом напруги та гармоніками для лінійних та нелінійних навантажень розподільчої мережі. Дослідження підтверджено результатами моделювання на основі програмного забезпечення MATLAB/Simulink

    UML Modeling for Tea / Coffee Machine

    Get PDF
    Unified Modeling language (UML) is one of the important modeling languages used for the visual representation of the research problem. In the present paper, UML model is designed for the Tea / Coffee Machine which is used for the purpose of the public in the hotels or restaurants2019;. The class and use case diagrams are designe

    Modulation of catalytic activity in multi-domain protein tyrosine phosphatases

    Get PDF
    Signaling mechanisms involving protein tyrosine phosphatases govern several cellular and developmental processes. These enzymes are regulated by several mechanisms which include variation in the catalytic turnover rate based on redox stimuli, subcellular localization or protein-protein interactions. In the case of Receptor Protein Tyrosine Phosphatases (RPTPs) containing two PTP domains, phosphatase activity is localized in their membrane-proximal (D1) domains, while the membrane-distal (D2) domain is believed to play a modulatory role. Here we report our analysis of the influence of the D2 domain on the catalytic activity and substrate specificity of the D1 domain using two Drosophila melanogaster RPTPs as a model system. Biochemical studies reveal contrasting roles for the D2 domain of Drosophila Leukocyte antigen Related (DLAR) and Protein Tyrosine Phosphatase on Drosophila chromosome band 99A (PTP99A). While D2 lowers the catalytic activity of the D1 domain in DLAR, the D2 domain of PTP99A leads to an increase in the catalytic activity of its D1 domain. Substrate specificity, on the other hand, is cumulative, whereby the individual specificities of the D1 and D2 domains contribute to the substrate specificity of these two-domain enzymes. Molecular dynamics simulations on structural models of DLAR and PTP99A reveal a conformational rationale for the experimental observations. These studies reveal that concerted structural changes mediate inter-domain communication resulting in either inhibitory or activating effects of the membrane distal PTP domain on the catalytic activity of the membrane proximal PTP domain

    Evaluation of Hepatoprotective activity of fruits of Sesbania grandiflora L. Pers against thiocetamide and ranitidine induced hepatotoxicity in rats

    Get PDF
    The Petroleum ether extract of Sesbania grandiflora L. pers fruits showed a significant dose dependent (100mg, 200mg/kg p.o.) protective effect against thioacetamide and ranitidine induced hepatotoxicity in Wistar albino rats. The degree of protection was measured by using biochemical parameters like Serum glutamic oxaloacetic transaminase (SGOT), Serum glutamic pyruvic transaminase (SGPT), Alkaline phosphatase (ALP), Total bilirubin (BRN), Total Cholesterol (TC), Total protein and Histopathological alterations. The fruit extract completely prevented the toxic effects of Thioacetamide and Ranitidine on the above serum parameters. The petroleum ether extract of Sesbania grandiflora L. pers fruits produced significant protectio

    Evaluation of Hepatoprotective activity of fruits of Sesbania grandiflora L. Pers against thiocetamide and ranitidine induced hepatotoxicity in rats

    Get PDF
    The Petroleum ether extract of Sesbania grandiflora L. pers fruits showed a significant dose dependent (100mg, 200mg/kg p.o.) protective effect against thioacetamide and ranitidine induced hepatotoxicity in Wistar albino rats. The degree of protection was measured by using biochemical parameters like Serum glutamic oxaloacetic transaminase (SGOT), Serum glutamic pyruvic transaminase (SGPT), Alkaline phosphatase (ALP), Total bilirubin (BRN), Total Cholesterol (TC), Total protein and Histopathological alterations. The fruit extract completely prevented the toxic effects of Thioacetamide and Ranitidine on the above serum parameters. The petroleum ether extract of Sesbania grandiflora L. pers fruits produced significant protectio

    Kloniranje, ekspresija i karakterizacija paraflagelarnog gena Rod 2 bičaša Trypanosoma evansi

    Get PDF
    Paraflagellar rod is the major structural component of the trypanosomatid flagellum and is identified as a complex lattice of filaments which runs parallel to the axoneme throughout most of the flagellar length. The present study was carried out to investigate the existence of the paraflagellar rod (PFR 2) gene in Trypanosoma evansi infecting Indian cattle. Local isolates of T. evansi collected from naturally infected cow were multiplied in Wistar rats. Complementary DNA (cDNA) was synthesized from the RNA of host cell free T. evansi parasites by reverse transcription. The gel purified PCR product (PFR 2 gene of T. evansi) was cloned into the pTZ57R/T vector system. The nucleotide sequence of the PFR 2 gene of the T. evansi S.V.V.U. isolate (Accession No. KT277497) obtained in the present study revealed 100% homology with T. evansi China isolate and 99% homology with T. evansi Izatnagar and Bikaner isolates. The recombinant protein was sub-cloned into pET 32a and expressed in the BL21 (DE3) pLysS expression system. The PFR 2 gene of T. evansi S.V.V.U. isolate was further characterized by determination of its protein profile with SDS-PAGE and western blotting. Indirect ELISA was optimized for detection of the specific antibody titre against the recombinant protein of the PFR 2 gene of T. evansi. In the kinetoplastid species the PFR 2 gene is highly conserved. Therefore the PFR 2 gene was suggested as a vaccine candidate, as well as a diagnostic antigen.Paraflagelarni štapić glavna je strukturna komponenta tripanosomskog biča i dio je kompleksa filamenaza koji teku paralelno s aksonemom duž biča. Istraživanje je provedeno kako bi se ispitalo postojanje paraflagelarnog gena Rod 2 (PFR2) u bičaša Trypanosoma evansi koji invadira goveda u Indiji. Lokalni izolat T. evansi prikupljen od prirodno invadiranih krava umnožen je u Wistar štakora. Komplementarna DNA (cDNA) sintetizirana je iz RNA obrnutom transkripcijom iz stanica neinvadiranih nositelja T. evansi parazita. Pročišćeni PCR produkt (gen PFR2 bičaša T. evansi) kloniran je u vektorski sustav pTZ57R/T. Nukleotidna sekvencija gena PFR2 bičaša T. evansi, izolat S.V.V.U. (pristupni broj KT277497) dobivena u ovom istraživanju pokazala je 100 %-tnu sličnost s izolatom T. evansi China i 99 %-tnu s izolatom T. evansi Izatnagar i Bikaner. Rekombinantni protein ponovno je kloniran u sustavu pET 32a i prikazan u sustavu BL21 (DE3) pLysS. Gen PFR2 bičaša T. evansi, izolat S.V.V.U. dalje je karakteriziran određivanjem proteinskog profila metodama SDS-PAGE i Western blotting. Indirektni test ELISA optimiziran je za dokaz titra specifičnih protutijela za rekombinantni protein gena PFR2 bičaša T. evansi. U kinetoplastida gen PFR2 izrazito je očuvan. Stoga bi se gen PFR2 mogao upotrijebiti za cjepivo te kao dijagnostički antigen
    corecore