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Electrical conductivity of Gd doped BiFeO3-PbZrO3 composite

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Frontiers of Materials Science 2013年第3期7卷 295-301页

作者： santosh kumar SATPATHY Nilaya kumar MOHANTY Ajay kumar BEHERA Banarji BEHERA Pratibindhya NAYAK Materials Research Laboratory School of Physics Sambalpur University Jyoti Vihar Burla-768019 Odisha India

The composite, 0.5（BiGd0.15Fe0.85O3）-0.5（PbZrO3）, was synthesized using the solid-state reaction technique. The formation of the compound was confirmed by XRD with an orthorhombic structure at room temperature. The impedance parameters were studied using an impedance analyzer in a wide range of frequency （10z-106Hz） at different temperatures. The Nyquist plot suggests the contribution of bulk effect and a slight indication of grain boundary effect and the bulk resistance decreases with a rise in temperature. The presence of temperature-dependent relaxation process occurs in the material. Electrical modulus reveals the presence of the hopping mechanism in the materials. The value of exponent n, pre-factor A and adc were obtained by fitting ac conductivity data with Jonscher＇s universal power law. The activation energies calculated from the ac conductivity were found to be 0.50, 0.46, 0.44, 0.43, 0.42 and 0.38 eV at 1, 10, 50, 100, 500 kHz and I MHz respectively in the temperature region of 110℃-350℃. The dc conductivity was found to increase with the rise in temperature. The activation energy calculated from complex impedance plot and from the fitted Jonscher＇s power law are very close, which results similar type of charge carrier exist in conduction mechanism of the material.

关键词： solid state reaction XRD impedance electrical conductivity

Diagnosis and Detection of Alzheimer’s Disease Using Learning Algorithm

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Big Data Mining and Analytics 2023年第4期6卷 504-512页

作者： Gargi Pant Shukla santosh kumar Saroj kumar Pandey Rohit Agarwal Neeraj Varshney Ankit kumar the Department of Management Doon Business SchoolDehradun 248001India. Jaipuria Institute of Management Jaipur 302033India Department of Computer Engineering and Apllications GLA UniversityMathura 281406India.

In Computer-Aided Detection(CAD)brain disease classification is a vital ***’s Disease(AD)and brain tumors are the primary reasons of *** studies of these diseases are carried out by Magnetic Resonance Imaging(MRI),Positron Emission Tomography(PET),and Computed Tomography(CT)scans which require expertise to understand the *** disease is the most prevalent in the elderly and can be fatal in its later *** result can be determined by calculating the mini-mental state exam score,following which the MRI scan of the brain is *** from that,various classification algorithms,such as machine learning and deep learning,are useful for diagnosing MRI ***,they do have some limitations in terms of *** paper proposes some insightful pre-processing methods that significantly improve the classification performance of these MRI ***,it reduced the time it took to train the model of various pre-existing learning algorithms.A dataset was obtained from Alzheimer’s Disease Neurological Initiative(ADNI)and converted from a 4D format to a 2D *** clipping,grayscale image conversion,and histogram equalization techniques were used to pre-process the *** pre-processing,we proposed three learning algorithms for AD classification,that is random forest,XGBoost,and Convolution Neural Networks(CNN).Results are computed on dataset and show that it outperformed with exiting work in terms of accuracy is 97.57%and sensitivity is 97.60%.

关键词： alzheimer’s disease deep learning random forest XGBoost

CFD modeling to study the effect of particle size on dispersion in 20l explosion chamber: An overview

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International Journal of Mining Science and Technology 2020年第3期30卷 321-327页

作者： santosh kumar Ray Niroj kumar Mohalik Asfar Mobin Khan Debashish Mishra Nikhil kumar Varma Jai Krishna Pandey Pradeep kumar Singh CSIR-Central Institute of Mining and Fuel Research Dhanbad 826001India

Mine disasters occur predominantly due to methane or coal dust explosion or a combination of *** the top ten worst coal mine disasters in India, nine are due to coal dust explosion. The current paper describes a general overview of the parameters causing dispersion leading to coal dust explosion,and computational fluid dynamics(CFD) simulation study to observe the effects of particle size on dispersion in Indian coal mines. Turbulent kinetic energy(TKE) and velocity vector path of dust-air mixture and dust-free air were simulated to understand their effects on coal dust dispersion. The TKE contours and velocity vector paths for dust-free air were uniform and symmetrical due to resistance-free path available. The TKE contours and velocity vector paths for dust-air mixture shows the asymmetrical distribution of contours, due to entrainment of air with dust particles. Vortices were observed in velocity vector paths which gradually diminish on increment of time sequence. These vortices are dead centres where velocity and coal dust particles concentration are both zero.

关键词： Coal dust explosibility CFD 20l explosion chamber Dispersion Turbulent kinetic energy

A detailed study on trust management techniques for security and privacy in IoT:challenges,trends,and research directions

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高置信计算(英文) 2023年第2期3卷 71-82页

作者： Himani Tyagi Rajendra kumar santosh Kr Pandey Department of Computer Science Jamia Millia IslamiaNew Delhi 110025India Department of EC&IT MeityNew Delhi 110003India

The Internet of Things is a modern technology that is directed at easing human life by automating most of the things used in daily *** never-ending dependency on the network for communication is attracting adversaries to exploit the vulnerabilities of ***,this technology is facing some serious issues and challenges concerning security and *** issues and challenges are the real motivation behind considering this ***,this survey includes a discussion about security and privacy challenges as well as available solutions for IoT based wireless sensor *** systematic literature review(SLR)focuses particularly on a popular and applicable security approach known as Trust Management System(TMS).Firstly,all aspects of trust management,including trust indicators,trust properties,trust evaluation,trust building,trust models and the importance of those models for security and privacy,trust prediction methodologies,and ultimately trust-based attacks,are covered in this ***,trust management schemes are classified into four groups based on the methodology used for trust-based security solutions in the IoT:cryptography-based,computational and probabilistic-based,information theory-based,and ***,an understanding of the problems and difficulties with current methodologies is given,along with suggestions for further ***,the SLR is concluded by formulating the desirable characteristics of a trust management system in the IoT and proposing a trust model suitable for IoT networks.

关键词： Trust Trust management approaches IoT Security Privacy Reliability Attacks Trust attributes Systematic literature review Cybersecurity

TGA/DSC study to characterise and classify coal seams conforming to susceptibility towards spontaneous combustion

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International Journal of Mining Science and Technology 2022年第1期32卷 75-88页

作者： Niroj kumar Mohalik Somu Mandal santosh kumar Ray Asfar Mobin Khan Debashish Mishra Jai Krishna Pandey CSIR-Central Institute of Mining and Fuel Research(CIMFR) Dhanbad 826015India Academy of Scientific and Innovative Research(AcSIR) Ghaziabad 201002India

Thermogravimetric analysis/differential scanning calorimeter(TGA/DSC)technique along with basic coal characteristics study is carried out for eighty coal samples of Indian coalfields,to determine spontaneous combustion propensity behaviour of *** study of coal samples indicates that there is an increase in the mass of coal samples in the temperature range 150-350℃,which may be due to oxygen adsorption and *** correlation and principal component analysis states that the component of proximate analysis(M_(ad),VM_(d),FR,and VR)have an acceptable correlation with the TGA experiments results i.e.,Tgsh and *** fixed nonlinear regression analysis shows that thermogravimetry(TG)experiment results Tgign may be the best index to categorise/classify the coal as per their susceptibility towards spontaneous *** authors proposed four groups of classification as per their propensity towards spontaneous combustion depending upon the moisture(M_(ad)),volatile matter(VM_(d)),and TG ignition temperature from differential thermogravimetric(DTG)curve(Tgign)using hierarchal clustering *** coal samples of different seams from Indian coalfield may be classified into four different clusters,*** highly/extremely susceptible(Tgign320℃).The field observations and TGA/DSC experiment results with the following statistical analysis substantiate a similar assessment.

关键词： Coal TGA/DSC Spontaneous combustion TG ignition

Impact of COVID-19 Pandemic on Mental Health of Healthcare Workers–A Perception of Indian Hospital Administrators

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International Journal of Mental Health Promotion 2023年第7期25卷 833-845页

作者： Anahita Ali santosh kumar Faculty of Public Health Poornima UniversityJaipur303905India

Since the coronavirus pandemic,many factors led to the change in the mental well-being of hospital administrators and their *** pandemic negatively impacted the availability and capability of health professionals to deliver essential services and meet rising ***,this study aimed to understand the perspective of hospital administrators about issues and challenges that negatively impacted their staff’s mental health and hospital administrators’coping response to mitigate those challenges and *** exploratory qualitative study was conducted with 17 hospital administrators(superintendents,deputy superintendents,nursing in charge and hospital in charge)working in a government district hospital of Rajasthan state during September 2022 and October *** study revealed various emerging themes on mental health-related issues,challenges and coping strategies reported by the *** and sub-themes that emerged from this study were 1)Perceived mental health of HCWs-perceived importance of mental health,2)Impact of COVID-19 on the mental health of HCWs–common mental health issues,changes in mental health pre and post-pandemic,3)Impact of COVID-19 on health behavior of HCWs-increased self-care and awareness,4)Challenges responsible for poor mental health of HCWs-organizational,ethical and societal challenges and 5)Strategies to retain mental health of HCWs-effective coping *** most common problems were increased levels of stress,feeling fatigued,tiredness,weak and anxiety among the *** their staff motivated was the biggest challenge *** support,counseling through professionals and demystifying myths were the most effective coping strategies adopted by the *** conclusion,this study reported poor mental health-related issues,challenges faced by the HCWs and effective strategies adopted by hospital administrators during tough *** study will assist hospital administrators in developing i

关键词： Coping strategies Indian administrators Indian healthcare workers qualitative study COVID-19 mental health

Bandgap engineered novel g-C_3N_4/G/h-BN heterostructure for electronic applications

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Journal of Semiconductors 2019年第3期40卷 45-49页

作者： santosh kumar Gupta Rupesh Shukla Department of Electronics & Communication Engineering Motilal Nehru National Institute of Technology Allahabad Department of Electrical & Electronics Engineering Loknayak Jai Prakash Institute of Technology Chhapra

The effect of an external electric field on the bandgap is observed for two proposed heterostructures graphitic carbon nitride-graphene-hexagonal boron nitride(g-C_3N_4/G/h-BN) in hexagonal stack(AAA) and graphene-graphitic carbon nitridehexagonal boron nitride(G/g-C_3N_4/h-BN) in Bernal stack(ABA). Their inter-layer distance, binding energy and effective mass has also been calculated. The structure optimization has been done by density functional theory(DFT) with van der Waals corrections. The inter-layer distance, bandgap, binding energy and effective mass has been listed for these heterostructures and compared with that of bilayer graphene(BLG), graphene-hexagonal boron nitride(G/h-BN) hetero-bilayer, graphene-graphitic carbon nitride(G/g-C_3N_4) hetero-bilayer and graphitic carbon nitride-graphene-graphitic carbon nitride(g-C_3N_4/G/g-C_3N_4) heterostructure in Bernal and hexagonal stack. g-C_3N_4/G/h-BN is found to offer lower effective mass and larger bandgap opening among the considered heterostructures.

关键词： bandgap graphene h-BN g-C3N4 binding energy DFT

Synthesis and characterization of rare earth metal doped tungsten trioxide photocatalyst for degradation of Rhodamine B dye

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稀土学报:英文版 2023年第9期41卷 1302-1310,I0002页

作者： Pooja Nehra Amita Khatri Anil kumar Satyendra Singh Pawan S.rana Department of Physics Deenbandhu Chhotu Ram University of Science and TechnologyMurthal1339SonipatHaryanaIndia Special Centre for Nanoscience Jawaharlal Nehru University New Delhi10067India

Nowadays,it is concern for researchers that due to high recombination rate of photogenerated charge carriers in tungsten trioxide(WO_(3)) nanoparticles,the future applications are limited in the field of *** we attempt to synthesize tungsten trioxide nanoparticles with different doping concentrations of lanthanum i.e.2 wt%,4 wt%,6 wt% and 8 wt%.The synthesized samples were characterized by using various characterization techniques:X-ray diffraction(XRD),Raman spectroscopy,Fourier transform infrared spectroscopy(FTIR),photoluminescence spectra(PL),transmission electron microscopy(TEM),energy dispersive X-ray(EDX) and UV-Vis ***_(3) retains its monoclinic structure even after doping which was confirmed by XRD *** helps to descry functional groups present in the *** size of nanoparticles was calculated by using *** confirms the absence of any impurity in the synthesized *** spectroscopy confirms the presence of a large number of imperfections induced in the lattice of WO_(3).The rate of recombination was analyzed by photoluminescence(PL) spectroscopy and is minimum in 4 wt% doping of *** optical bandgap was calculated using UV-Vis spectroscopy and becomes narrow along with the doping ***,it is found that doping of La in WO_(3) has considerably ameliorate the photocatalytic activity by reducing rate of recombination due to the trapping of electrons by defects introduced in the *** decolorization of Rhodamine B(RhB) dye was performed and the values of c/c_0 and rate constant(k) confirm that the 4 wt% doping shows maximum degradation *** kinetic study for photodegradation of Rhodamine B was done by using various kinetic models and results show that the reaction follows first order kinetics very ***,optimum doping of lanthanum increases the decolorization ability of WO_(3) towards RhB dye.

关键词： Photocatalytic activity WO_(3)nanoparticles Rhodamine B dye Rare earth doping Visible light

YFa and analogs:Investigation of opioid receptors in smooth muscle contraction

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World Journal of Gastroenterology 2011年第40期17卷 4523-4531页

作者： Krishan kumar Ritika Goyal Annu Mudgal Anita Mohan santosh Pasha Peptide Synthesis Laboratory Institute of Genomics and Integrative Biology Delhi 110007 India University School of Basic and Applied Sciences GGSIP University Sector-16 C Dwarka Delhi 110075 India Department of Chemistry Motilal Nehru College University of Delhi Delhi 110021 India

AIM:To study the pharmacological profile and inhibition of smooth muscle contraction by YFa and its analogs in conjunction with their receptor selectivity. METHODS:The effects of YFa and its analogs (D-Ala2) YFa, Y (D-Ala2) GFMKKKFMRF amide and Des-Phe-YGGFMKKKFMR amide in guinea pig ileum (GPI) and mouse vas deferens (MVD) motility were studied using an isolated tissue organ bath system, and morphine and DynA (1-13) served as controls. Acetylcholine was used for muscle stimulation. The observations were validated by specific antagonist pretreatment experiments using naloxonazine, naltrindole and norbinaltor-phimine norBNI. RESULTS:YFa did not demonstrate significant inhibition of GPI muscle contraction as compared with mor-phine (15% vs 62%, P = 0.0002), but moderate inhibition of MVD muscle contraction, indicating the role of κ opioid receptors in the contraction. A moderate inhibition of GPI muscles by (Des-Phe) YFa revealed the role of anti-opiate receptors in the smooth muscle contraction. (D-Ala-2) YFa showed significant inhibition of smooth muscle contraction, indicating the involvement of mainly δ receptors in MVD contraction. These results were supported by specific antagonist pretreatment assays. CONCLUSION:YFa revealed its side-effect-free analgesic properties with regard to arrest of gastroin-testinal transit. The study provides evidences for the involvement of κ and anti-opioid receptors in smooth muscle contraction.

关键词： Opioid receptor Guinea pig ileum Mousevas deferens Smooth muscle contraction Gastrointestinal motility