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Study of electronic structure and dielectric properties of Gd-doped cobalt nanoferrites
Kumar Arvind,Gora Mahendra Kumar,Kumar Sanjay,Choudhary Banwari Lal,Singhal Rishi Kumar,Dolia Satya Narain 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.81 No.9
The current article explores the dielectric and electronic properties of cobalt ferrite nanoparticles with Gd substitution in a series CoGdxFe2-xO4 (0≤x≤0.1, in step x=0.02) synthesized by the sol–gel self-combustion way. All the samples were studied with Fourier transform infra-red (FTIR) spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and impedance (dielectric) analyzer. One absorption band (υ1) was observed in FTIR measurements, which is the characteristic feature of spinel nanoferrites in fcc type structure. The presence of active Raman modes in Raman spectra at room temperature demonstrated single phase formation of cobalt nanoferrites with metallic–metallic and metallic–oxygen bonding vibrations in the tetrahedral and octahedral sites. XPS data analysis confrmed phase purity and revealed incorporation of Gd ion in the spinel fcc lattice. The valence states of Fe, Co & Gd atoms in all these nanoparticles are found as Fe3+, Co2+, & Gd3+. The dielectric constant and dielectric loss are measured in a broad frequency range of 100 Hz to 120 MHz. The dielectric constant reduces with a rise in Gd concentration and frequency. This study reveals that electronic and dielectric properties could be efectively tuned by varying concentrations of gadolinium in cobalt ferrite nanoparticles.
Computer-Aided Genetic Algorithm Based Multi-Objective Optimization of Laser Trepan Drilling
Sanjay Kumar,Avanish Kumar Dubey,Arun Kumar Pandey 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.
The laser trepan drilling (LTD) has proven to produce better quality holes in advanced materials as compared with laser percussion drilling (LPD). But due to thermal nature of LTD process, it is rarely possible to completely remove the undesirable effects such as recast layer, heat affected zone and micro cracks. In order to improve the hole quality, these effects are required to be minimized. This research paper presents a computer-aided genetic algorithm-based multi-objective optimization (CGAMO) methodology for simultaneous optimization of multiple quality characteristics. The optimization results of the software CGAMO has been tested and validated by the published literature. Further, CGAMO has been used to simultaneously optimize the recast layer thickness (RLT) at entrance and exit in LTD of nickel based superalloy sheet. The predicted results show minimization of 99.82% and 85.06% in RLT at entrance and exit, respectively. The effect of significant process parameters on RLT has also been discussed.
( Kumar Sanjay ),( Urmil Tuteja ),( Kumari Sarika ),( Dhirendra Kumar Singh ),( Ashok Kumar ),( Om Kumar ) 한국미생물 · 생명공학회 2011 Journal of microbiology and biotechnology Vol.21 No.1
The routine identification and differentiation of Brucella species is a time-consuming and labor-intensive process, which frequently places personnel at risk of laboratory-acquired infection. Here, we describe the development of a rapid multiplex PCR assay for the confirmation of presumptive Brucella isolates. The assay was able to identify and differentiate major human pathogens, namely B. abortus, B. melitensis, and B. suis, in a single test of less than an hour and a half.
Sanjay Kumar,Sujeet Kumar Singh Gautam,Devendra Gupta,Anil Agarwal,Sanjay Dhirraj,Sandeep Khuba 대한마취통증의학회 2016 Korean Journal of Anesthesiology Vol.69 No.1
Background: Valsalva maneuver reduces pain by activating sinoaortic baroreceptor reflex arc. We planned this study to evaluate the role of valsalva in attenuating spinal needle-puncture pain. Methods: Ninety American Society of Anesthesiologists (ASA) grade I and II enrolled patients undergoing elective surgery were randomized into 3 groups of 30 each. Group I (Control): didn’t blow; group II (Distraction): patients blew into rubber tube; Group III (Valsalva): blew into sphygmomanometer tube and raise mercury column up to 30 mmHg for at least 20 seconds. During above procedures, spinal puncture was performed with 25-gauge spinal needle. Results: Eighty-two patient data were analyzed. Incidence of spinal puncture pain was reduced to 10% (3 of 27) in Valsalva group as compared to 100% (28 of 28 in control group and 27 of 27 in Distraction group) observed in other two groups (P < 0.05). Severity of lumbar puncture pain as assessed by visual analog scale (0−10; where 0 is no pain and 10 is the worst imaginable pain) presented as Median (Interquartile range) were significantly reduced in the Valsalva group (0.0 [0.0] as compared to other 2 groups 2.0 [0.0] in the Distraction group and 3.0 [0.8] in Control group) (P < 0.05). Regarding time taken by CSF to fill spinal needle hub, there was no difference among the three groups (P > 0.05). None patient of all groups had post dural puncture headache (P > 0.05). Conclusions: Valsalva can be performed routinely in ASA I and II patients undergoing spinal anesthesia as it is safe, painless and non-pharmacological method of pain attenuation.
( Sanjay Kumar ),( Omprakash Sanjeev ),( Anil Agarwal ),( Chetna Shamshery ),( Rakhi Gupta ) 대한통증학회 2018 The Korean Journal of Pain Vol.31 No.1
Background: Venipuncture pain is an uncomfortable suffering to the patient. It creates anxiety, fear and dissatisfaction. The ketoprofen transdermal patch is a proven treatment for musculoskeletal and arthritic pain. We planned this study to evaluate the efficacy of the ketoprofen patch to reduce venipuncture pain. Methods: Two hundred adult patients, aged 18-60 years, of either sex, ASA grade I or II, were enrolled. Presuming that therapy would decrease venipuncture pain by 30%, a power calculation with α = 0.05 and β = 0.80 required enrollment of at least 24 patients into each group. However, 100 patients in each group were recruited. Group I (Control) received a placebo patch; Group II (Ketoprofen) received a 20 mg ketoprofen patch. A selected vein on the dorsum of the patient’s non-dominant hand was cannulated with 18 g intravenous cannula 1 h after the application of the respective patch. Assessment of pain was done by a 10 cm visual analogue scale (VAS) of 0-10, where 0 depicts “no pain” and 10 is “the worst imaginable pain”. The venipuncture site was assessed for the presence of skin erythema, swelling and rashes at 12 h, 24 h and at the time of decannulation. Results: Incidence of pain was 100% (94/94) in the control group as compared to 93% (85/91) in the ketoprofen group. The severity of the venipuncture pain was 6 (2) and 2 (2) for control and ketoprofen groups respectively (P < 0.05). Conclusions: Application of a ketoprofen patch at the proposed site of venipuncture one hour before the attempt is effective and safe for attenuating venipuncture pain. (Korean J Pain 2018; 31: 39-42)
Sanjay Kumar,Ajay 한국물리학회 2015 Current Applied Physics Vol.15 No.10
Calculations of renormalized perpendicular conductivity within Kubo formula employing single particle temperature dependent Green's function formalism for bilayer graphene has been attempted. On the basis of numerical analysis, perpendicular conductivity as a function of temperature, interlayer coupling, onsite Coulomb interaction and carrier concentration per site has been analyzed for both AA- and ABstacked bilayer graphene. It is found that perpendicular conductivity increases with interlayer coupling and also with temperature at low temperatures while at higher temperatures, there is saturation in perpendicular conductivity. Influences of onsite Coulomb interaction and carrier concentration per site on perpendicular conductivity is just opposite to each other while onsite Coulomb energy suppresses the rate of increase of σ⊥/σ⊥0 with temperature, on the other hand increase in carrier density per site enhance this rate significantly. Finally, theoretically obtained results on temperature dependent perpendicular conductivity are viewed in terms of electronic transport data as well as recent theoretical works available in bilayer graphene.
Sanjay Kumar,Sandeep Khuba,Anil Agarwal,Sujeet Gautam,Madhulika Yadav,Aanchal Dixit 대한마취통증의학회 2018 Korean Journal of Anesthesiology Vol.71 No.6
Background: Pain on injection is a limitation with propofol use. The effect of the Valsalva maneuver on pain during propofol injection has not been studied. This maneuver reduces pain through the sinoaortic baroreceptor reflex arc and by distraction. We aimed to assess the efficacy of the Valsalva maneuver in reducing pain during propofol injection. Methods: Eighty American Society of Anesthesiologists class I adult patients undergoing general anesthesia were enrolled and divided into two groups of 40 each. Group I (Valsalva) patients blew into a sphygmomanometer tube raising the mercury column up to 30 mmHg for 20 seconds, while Group II (Control) patients did not. Anesthesia was induced with 1% propofol immediately afterwards. Pain was assessed on a 10-point visual analog scale (VAS), where 0 represented no pain, and 10, the worst imaginable pain, and a 4-point withdrawal response score, where 0 represented no pain, and 3, the worst imaginable pain. Scores were presented as median (interquartile range). Results: We analyzed the data of 70 patients. The incidence of pain was significantly lower in the Valsalva than in the control group (53% vs. 78%, P = 0.029). The withdrawal response score was significantly lower in the Valsalva group (1.00 [0.00–1.00] vs. 2.00 [2.00–3.00], P < 0.001). The VAS score was significantly lower in the Valsalva group (1.00 [0.00–4.00] vs. 7.00 [6.25–8.00], P < 0.001). Conclusions: A prior Valsalva maneuver is effective in attenuating injection pain due to propofol; it is advantageous in being a non-pharmacological, safe, easy, and time-effective technique.
SINR Pricing in Non Cooperative Power Control Game for Wireless Ad Hoc Networks
( Sanjay Kumar Suman ),( Dhananjay Kumar ),( L. Bhagyalakshmi ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.7
In wireless ad hoc networks the nodes focus on achieving the maximum SINR for efficient data transmission. In order to achieve maximum SINR the nodes culminate in exhausting the battery power for successful transmissions. This in turn affects the successful transmission of the other nodes as the maximum transmission power opted by each node serves as a source of interference for the other nodes in the network. This paper models the choice of power for each node as a non cooperative game where the throughput of the network with respect to the consumption of power is formulated as a utility function. We propose an adaptive pricing scheme that encourages the nodes to use minimum transmission power to achieve target SINR at the Nash equilibrium and improve their net utility in multiuser scenario.