38 research outputs found

    Modeling of SEPIC Fed PMBLDC Motor for Torque Ripple Minimization

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    BLDC Motor suffers from commutation torque ripple, which mainly depends on stator winding impedance, speed and transient line current in the conduction interval. This paper describes a novel circuit topology and a dc input link voltage control strategy to keep incoming and outgoing phase currents changing at the same rate during commutation interval. A SEPIC (single-ended primary inductor converter) and a switch selection circuit are employed in the front of the inverter. The desired commutation voltage is obtained by the SEPIC converter. The input dc link voltage control strategy is carried out by the switch selection circuit to separate two procedures, adjusting the SEPIC converter and regulating speed. The commutation torque ripple is analyzed, and introduced the way to obtain the desired dc link voltage in detail. Finally, simulation and experimental results show that, compared with conventional and the proposed method can obtain the desired voltage is obtained and minimize commutation torque ripple more efficiently

    Enantio-differentiation of molecules with diverse functionalities using a single probe

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    This study reports (1S,2S)-N,N'-dihydroxy-N,N'-bis(diphenylacetyl)-1,2-cyclohexanediamine, a C-2 symmetric chiral hydroxamic acid ((S)-CBHA-DPA), as a unique probe for discrimination of molecules with diverse functionalities. The proposed CSA is also utilized for the accurate measurement of enantiomeric excess

    Two- and Three-Centered Hydrogen Bonds Involving Organic Fluorine Stabilize Conformations of Hydrazide Halo Derivatives: NMR, IR, QTAIM, NCI, and Theoretical Evidence

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    The presence of two- and three-centered hydrogen bonds (HB) of the type H­(N)···XC and CO···H­(N)···XC, respectively, involving organic fluorine in the synthesized hydrazide halo derivatives have been convincingly established by extensive multidimensional NMR studies. The stabilized conformation of the molecules involving two- and three-centered HBs derived by NMR studies have been further confirmed by density functional theory (DFT)-based calculations, such as quantum theory of atoms in molecules (QTAIM), noncovalent interaction (NCI), and relaxed potential energy scan

    Smart Locomotive Engine using GPS system

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    Rail  tracking  system  (RTS) is  an  advanced method used to track and monitor any train equipped with a  sensing  unit  that  receives  and  transfers signals  through GPS  satellite. RTS is a combination of Global Positioning System (GPS) that provides actual geographic real time position of each train. The entire transmission mechanism of RTS setup depends on GPS satellite, a receiver on the train, a GSM system and  controller based  tracking  for dispatch. The GSM communication system is generally the same as cellular phone network. In the existing system passenger cant able to identify the train location. In this project we are identifying the train speed, location and providing message via SMS by applying GPS technique. It is very useful to the passenger those who are sleeping while travelling. In case of emergency when passenger using emergency chain, we can also indicate that in which compartment the chain is pulled

    p-TsOH promotes 2 `-amino-1,1 `-binaphthalene]-2-ol as a chiral solvating agent

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    2'-Amino-1,1'-binaphthalene]-2-ol (NOBIN) fails to serve as a chiral solvating agent (CSA) for acids, hydroxy acids and their derivatives due to its negligibly weak or absence of weak molecular interactions with the chiral analyte. In the present study, we demonstrate the utility of NOBIN as a CSA for discrimination of acids, hydroxy acids and their derivatives with a distinct strategy wherein a third ingredient, p-toluenesulphonic acid (p-TsOH), was introduced as a linker, which induces hydrogen bonding interactions and thus permits the NMR spectroscopic differentiation. The formation of ternary complex is further established by UV-Vis, fluorescence, IR and PXRD studies. Ternion complex structures were optimized by the DFT calculations

    Intramolecular Hydrogen Bonding Appetency for Conformational Penchants in Oxalohydrazide Fluoro Derivatives: NMR, MD, QTAIM, and NCI Studies

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    The conformational stability of synthesized diphenyloxalohydrazide and dibenzoyloxalohydrazide fluoro derivatives has been investigated by extensive NMR studies that are ascertained by various levels of theoretical calculations. Two-dimensional H-1-F-19 HOESY NMR experiments revealed the close spatial proximity between two NMR-active nuclei, confirming the hydrogen bond (HB)-mediated interaction between them, further aiding in establishing the probable stable conformations of these molecules. The relaxed potential energy scan disclosed the energy-minimized most stable structure among the several possible multiple conformations, which is in concurrence with NMR interpretations. Atomistic molecular dynamics simulations have been employed to unequivocally establish the conformational stability and the nature of HB formation at varied temperatures. With the possibility of occurrence of a number of probable conformations, the percentage of occurrences of different types of HBs in them was determined by MD simulations. Their population analysis was carried out using a Boltzmann distribution, in addition to deriving their Gibbs free energies. The molecular interactions governing the stable conformations have not only been ascertained by experimental NMR interpretations but also corroborated by other theoretical computations, viz., quantum theory of atoms in molecules (QTAIM) and noncovalent interaction (NCI)

    Three centered hydrogen bonds of the type C=O...H(N)...X-C in diphenyloxamide derivatives involving halogens and a rotating CF3 group: NMR, QTAIM, NCI and NBO studies

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    The existence of three centered C=O...H(N)...X-C hydrogen bonds (H-bonds) involving organic fluorine and other halogens in diphenyloxamide derivatives has been explored by NMR spectroscopy and quantum theoretical studies. The three centered H-bond with the participation of a rotating CF3 group and the F...H-N intramolecular hydrogen bonds, a rare observation of its kind in organofluorine compounds, has been detected. It is also unambiguously established by a number of one and two dimensional NMR experiments, such as temperature perturbation, solvent titration, N-15-H-1 HSQC, and F-19-H-1 HOESY, and is also confirmed by theoretical calculations, such as quantum theory of atoms in molecules (QTAIM), natural bond orbital (NBO) and non-covalent interaction (NCI)
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