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Yash Pal,A. Swarup,Bhim Singh 전력전자학회 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.4
This paper presents a novel control strategy for selective compensation of power quality (PQ) problems, depending upon the limited rating of voltage source inverters (VSIs), through a unified power quality conditioner (UPQC) in a three-phase four-wire distribution system. The UPQC is realized by the integration of series and shunt active power filters (APFs) sharing a common dc bus capacitor. The shunt APF is realized using a three-phase, four-leg voltage source inverter (VSI), while a three-leg VSI is employed for the series APF of the three-phase four-wire UPQC. The proposed control scheme for the shunt APF, decomposes the load current into harmonic components generated by consumer and distorted utility. In addition to this, the positive and negative sequence fundamental frequency active components, the reactive components and harmonic components of load currents are decomposed in synchronous reference frame (SRF). The control scheme of the shunt APF performs with priority based schemes, which respects the limited rating of the VSI. For voltage harmonic mitigation, a control scheme based on SRF theory is employed for the series APF of the UPQC. The performance of the proposed control scheme of the UPQC is validated through simulations using MATLAB software with its Simulink and Power System Block set toolboxes.
A Novel Control Strategy of Three-phase, Four-wire UPQC for Power Quality Improvement
Yash Pal,A. Swarup,Bhim Singh 대한전기학회 2012 Journal of Electrical Engineering & Technology Vol.7 No.1
The current paper presents a novel control strategy of a three-phase, four-wire Unified Power Quality (UPQC) to improve power quality. The UPQC is realized by the integration of series and shunt active power filters (APF) sharing a common dc bus capacitor. The realization of shunt APF is carried out using a three-phase, four-leg Voltage Source Inverter (VSI), and the series APF is realized using a three-phase, three-leg VSI. To extract the fundamental source voltages as reference signals for series APF, a zero-crossing detector and sample-and-hold circuits are used. For the control of shunt APF, a simple scheme based on the real component of fundamental load current (I CosΦ) with reduced numbers of current sensors is applied. The performance of the applied control algorithm is evaluated in terms of power-factor correction, source neutral current mitigation, load balancing, and mitigation of voltage and current harmonics in a three-phase, four-wire distribution system for different combinations of linear and non-linear loads. The reference signals and sensed signals are used in a hysteresis controller to generate switching signals for shunt and series APFs. In this proposed UPQC control scheme, the current/voltage control is applied to the fundamental supply currents/voltages instead of fast-changing APF currents/voltages, thus reducing the computational delay and the required sensors. MATLAB/Simulink-based simulations that support the functionality of the UPQC are obtained.
Yashpal S. Malik,Kuldeep Sharma,Nirupama Vaid,Somendu Chakravarti,K. M. Chandrashekar,Sanjay S. Basera,Rashmi Singh,Minakshi,Gaya Prasad,Baldev R. Gulati,Kiren N. Bhilegaonkar,Awadh B. Pandey 대한수의학회 2012 JOURNAL OF VETERINARY SCIENCE Vol.13 No.3
The present study describes the genotypic distribution of rotaviruses (RVs) in an Indian bovine population with unexpectedly higher proportions of G3 alone or in combination of G8/G10. PCR-genotyping confirmed that 39.4% (13/33) of the prevalent RVs were the G3 type while 60.6% (20/33) were dual G3G10 or G3G8 types. P typing revealed that 93.9% (31/33) of the samples were P[11] while 6.1% (2/33) possessed a dual P[1]P[11] type. Sequence analysis of the VP7 gene from G3 strains viz. B-46, 0970, and BR-133 showed that these strains had sequence identities of 90.5% to 100% with other bovine G3 strains. The highest identity (98.9% to 100%) was observed with RUBV3 bovine G3 strains from eastern India. The G3 strains (B-46, 0970, and BR-133) showed 97.5% to 98.8% sequence homologies with the Indian equine RV strain Erv-80. Phylogenetic analysis demonstrated that G3 strains clustered with bovine RUBV3 and J-63, and equine Erv-80 G3. Overall, these results confirmed that the incidence of infection by RVs with the G3 genotype and mixed genotypes in the bovine population was higher than previously predicted. This finding reinforces the importance of constantly monitoring circulating viral strains with the G3 genotype in future surveillance studies.
Singh, Yashpal,Back, Seoin,Jung, Yousung The Royal Society of Chemistry 2018 Physical chemistry chemical physics Vol.20 No.32
<P>Novel monolayer-boron (borophene) is a recent addition to the family of 2D materials. In particular, full surface hydrogenation of triangular borophene (borophane (BH)) to passivate empty p orbitals in boron is identified as producing a new stable 2D material that possesses direction-dependent Dirac cones similar to graphene. By a series of density functional theory (DFT) computations, we investigated the potential of single transition metal atoms supported on borophane with vacancies (the TM-BH system) as an efficient ORR/OER electrocatalyst for applications in renewable energy technologies. In TM-BH systems, the coupling of d-orbitals of the TM dopant with the p-orbitals of surrounding boron atoms results in an increase in the density of states near the Fermi-level generating active sites to facilitate the ORR/OER <I>via</I> an efficient four-electron transfer mechanism. Among the considered TM-BH systems, Fe-BH and Rh-BH were found to be promising ORR electrocatalysts with overpotentials (<I>η</I><SUP>ORR</SUP>) of 0.43 V and 0.47 V, respectively, whereas, for the OER, Rh-BH with 0.24 V has the smallest <I>η</I><SUP>OER</SUP> value followed by Co-BH (0.37 V), under the equilibrium electrode potential. These <I>η</I><SUP>ORR</SUP> and <I>η</I><SUP>OER</SUP> values indicate higher activities than the current most active ORR (Pt(111) (0.63 V)) and OER (rutile-type RuO2 (0.37 V)) electrocatalysts.</P>
Jain, Rishabh,Singh, Yashpal,Cho, Soo-Yeon,Sasikala, Suchithra Padmajan,Koo, Sung Hwan,Narayan, Rekha,Jung, Hee-Tae,Jung, Yousung,Kim, Sang Ouk American Chemical Society 2019 Chemistry of materials Vol.31 No.8
<P>Phosphorene suffers from instability under ambient condition, despite its potential to bridge the gap between graphene and two-dimensional (2D) metal chalcogenides. We report effective exfoliation and stabilization of few layer phosphorene (FLP) in the presence of strongly interacting surfactants. Surfactants containing long hydrophobic chain and nonbulky charged headgroups (CTAB) effectively exfoliate and stabilize FLP in water, which is consistent with our density functional theory prediction. Nuclear magnetic resonance measurements are systematically employed to probe the interaction between surfactants and FLP. Retarded diffusion rate measured by 2D DOSY spectroscopy revealed the presence of noncovalently bonded CTAB over phosphorene. 2D NOESY spectroscopy further suggests the interdigitated arrangement of surfactants. Such a tight interaction impedes the ambient degradation rate of phosphorene by 70-80%. This work proposes a new insight into the control over ambient degradation of phosphorene without altering its intrinsic properties.</P> [FIG OMISSION]</BR>
High performance of InGaN light-emitting diodes by air-gap/GaN distributed Bragg reflectors.
Ryu, Jae Hyoung,Kim, Hee Yun,Kim, Hyun Kyu,Katharria, Yashpal Singh,Han, Nam,Kang, Ji Hye,Park, Young Jae,Han, Min,Ryu, Beo Deul,Ko, Kang Bok,Suh, Eun-Kyoung,Hong, Chang-Hee Optical Society of America 2012 Optics express Vol.20 No.9
<P>The effect of air-gap/GaN DBR structure, fabricated by selective lateral wet-etching, on InGaN light-emitting diodes (LEDs) is investigated. The air-gap/GaN DBR structures in LED acts as a light reflector, and thereby improve the light output power due to the redirection of light into escape cones on both front and back sides of the LED. At an injection current of 20 mA, the enhancement in the radiometric power as high as 1.91 times as compared to a conventional LED having no DBR structure and a far-field angle as low as 128.2° are realized with air-gap/GaN DBR structures.</P>
Madan Mohan Pandey,Raghavan Govindarajan,Ajay Kumar Singh Rawat,Yashpal Singh Pangtey,Shanta Mehrotra 한국생약학회 2004 Natural Product Sciences Vol.10 No.1
A simple quantitative HPLC method has been developed for differentiating two plants of Asteraceae family viz. S. costus and A. lappa by using a pharmacologically active constituent chlorogenic acid and symmetry C18 column clubbed with a binary gradient using acetonitrile: 0.1% phosphoric acid and detected using a PDA at 327nm. Quantitatively chlorogenic acid was found to be more in A. lappa (0.140%) than in S. costus (0.087%).
Ashima Malhotra,Vikas Gupta,Mary Abraham,Pankaj Punetha,Yashpal Bundela 대한척추외과학회 2016 Asian Spine Journal Vol.10 No.2
Study Design: Prospective, randomised controlled, single centre study of 45 patients posted for two level lumbar fixation surgery in the prone position. Purpose: To compare intra-abdominal pressure (IAP), mean airway pressure mean airway pressure and blood loss during the spine surgery in prone position using three different positioning systems. Overview of Literature: Studies have correlated IAP with the amount of perioperative bleeding. However, IAP and airway pressures while assessing the bleeding comparing two or more prone positioning systems are unclear. Methods: This prospective study was conducted on a cohort of 45 patients scheduled for two-level lumbar fixation. Patients were randomly allocated to a spine table, Wilson’s frame, and thermomodulated pads. Bladder pressure as an indicator of IAP, mean and peak airway pressures, and blood loss were monitored. Results: IAP increased whenever patient position was changed to prone .The increase in pressure was more in the Wilson’s frame group but was statistically significant only on prolonged positioning. Adopting the prone position always increased the mean airway pressure, but the increased was significant only in the Wilson’s frame group. Mean airway pressure decreased in the spine table group and was statistically significant. The blood loss in the spine table group was significantly less as compared to the other groups. Conclusions: Positioning on a spine table results in less blood loss and low mean airway pressure. The Wilson’s frame results in high IAP, increased mean airway pressure, and more blood loss. The thermomodulated frame increases mean airway pressure and produces a moderate increase in IAP and airway pressure.
Manish Srivastava,Jay Singh,Rajneesh K. Mishra,Manish K. Singh,Animesh K. Ojha,Madhu Yashpal,Srivastava Sudhanshu 한국물리학회 2014 Current Applied Physics Vol.14 No.7
A study on Lithium ferrite/chitosan nanocomposite (LFCN), easily moldable into arbitrary shapes, as the conducting polymer and ferromagnetic characteristics is presented. The composite material is produced in the presence of Li0.5Cr0.1Fe2.4O4 and Li0.5Co0.1Fe2.4O4 nanoparticle by ex-situ polymerizations process. Various characterizations techniques have been used to explore the characteristic of the synthesized products. The frequency dependent dielectric properties and electrical conductivity of all the samples have been measured through complex impedance plot in the frequency range of 1 kHze6 MHz at room temperature. It was observed that in case of (LFCN), fluctuation in value of (ε 0) and (ε 00) is ceased over the frequency range of 4 Mz which can be attributed to the steady storage and dissipation of energy in the nanocomposite system. Moreover, it is also observed that electrical conductivity of (LFCN) increases with frequency and its value was found to be (0.032e0.048) (ohm-cm)1 in frequency range of 1 kHze6 MHz. Due to its low cost, a simple synthesis process and high flexibility, the proposed LFCN may find applications in various types of electronic components.