Liquid Phase Exfoliation and Characterization of Few Layer MoS2 and WS2 Nanosheets as Channel Material in Field Effect Transistor

Rohit Sharma,Ashish Kumar,Anit Dawar,Sunil Ojha,Ambuj Mishra,Anshu Goyal,Radhapiyari Laishram,V. G. Sathe,RITU SRIVASTAVA,Om Prakash Sinha 한국전기전자재료학회 2023 Transactions on Electrical and Electronic Material Vol.24 No.2

Field effect transistors (FETs) are considered as the backbone of electronic industry. In this study, we adopted a simple drop cast method for the fabrication of MoS2 and WS2 channel based FET on commercially available pre-patterned OFET devices. The synthesis of few-layers thick MoS2 and WS2 nanosheets (NSs) has been done by solvent-assisted exfoliation method. FESEM and TEM study reveals that NSs have lateral dimensions in micron and have polycrystalline nature. From XPS, it is observed that MoS2 NSs has 2H phase whereas WS2 have hybrid 1T and 2H phase. The frequency difference in Raman vibrational mode for MoS2 and WS2 NSs is 24.08 cm-1 and 63.84 cm-1 respectively, confirms that number of layers is reduced after sonication. UV-visible spectroscopy reveals that the bandgap is 1.7 eV and 1.8 eV for MoS2 and WS2 NSs respectively. Later, these nanosheets have been drop-casted as the channel material on pre-patterned FETs devices and their output and transfer characteristics have been studied. It found that the current On/Off ratio is 10 4 and 10 3 for MoS 2 and WS2-FET device respectively. This facile fabrication of FET devices may provide a new stage for researchers who do not have access of lithography facilities for FET fabrication.

Modelling of the Thermophysical Properties in Ar-He-H<SUB>2</SUB> Thermal Plasmas with Electronic Excitation

Rohit Sharma,Gurpreet Singh,Kuldip Singh 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.6

The role of electronically excited states (EES) in the thermophysical properties of a ternary Ar-He-H<SUB>2</SUB> mixture has been examined in the temperature range from 6000 to 40000 K at pressures of p = 0.1, 1.0, and 5.0 atm in local thermodynamic equilibrium (LTE). The influence of electronic excitation was observed to be enhanced with increasing pressure, and for pressures from p = 0.1 to 1.0 atm, the enthalpy, frozen specific heat, total specific heat, electrical conductivity and electron thermal conductivity were enhanced by 1.22%, 30%, 5%, 1.5%, and 2%, respectively, whereas for pressures p = 1.0 to 5.0 atm, the enhancements in these properties were 2.8%, 20%, 6%, 4.5%, and 14.3%, respectively. At higher pressures (p = 5 atm), pronounced contributions to these properties of 11%, 62%, 26%, 18%, and 28%, respectively were noted. Due to the significant contribution of electronic excitation to these properties, considering its influence in modelling plasma processes is important.

Assessment of Synergistic Impact of Ambient Surface Ozone and Fine Particulate Matter on Experimentally Grown Wheat Crop

Rohit Sharma,Kamna Sachdeva,Anu Rani Sharma 한국대기환경학회 2021 Asian Journal of Atmospheric Environment (AJAE) Vol.15 No.1

The present study aims to understand how increasing surface ozone and fine particulate matter concentrations affect wheat crop productivity under ambient conditions. A pot experiment was conducted spanning over a period of 117 days starting from December 2016 to April 2017 at one of the receptor locations in Delhi characterized with high levels of surface ozone and fine particulate matter. The study site recorded highest concentrations of PM1, PM2.5, PM10 and surface ozone of 159±77 μg m-3, 172±79 μg m-3, 280±108 μg m-3 and 335±18 μg m-3, respectively during the crop cycle indicating the high levels of air pollutants at the site. The crops were treated with ascorbic acid under different experimental setups. A large number of growth, biochemical and yield parameters were evaluated at the vegetative, reproductive and grain formation stage of the crop cycle. Results indicated that the chlorophyll content and harvest yield of crops grown under ambient conditions were ~23% and ~14% lower than those of crops grown under controlled environment. Furthermore, a ~13%, 5%, 15% and 10% decline in root length, plant height, number of tillers and number of leaves was observed in crops that were exposed to only surface ozone in comparison to crops exposed to only fine particulate matter under vegetative stage, respectively. Relative water content, chlorophyll content and air pollution tolerance index observed ~56%, 23% and 61% decline with fully exposed setup in comparison control setup in the vegetative stage, while ~57%, 23% and 44% decline was observed in the reproductive stage. Experiments also suggested that surface ozone had a more pronounced influence on overall productivity of wheat crops in comparison to fine particulate matter.

Error Resilient SPIHT Coded Grayscale Image transmission over MIMO System

Rohit Kumar Murarka,Anurag Mishra,Kanchan Sharma 보안공학연구지원센터 2014 International Journal of Hybrid Information Techno Vol.7 No.5

On the effect of spray parameters on CO and NO_x emissions in a liquid fuel fired flameless combustor

Sharma, Saurabh,Kumar, Rohit,Chowdhury, Arindrajit,Yoon, Youngbin,Kumar, Sudarshan Elsevier 2017 Fuel Vol.199 No.-

<P><B>Abstract</B></P> <P>In this paper, numerical and experimental investigations have been carried out to delineate the effect of various spray parameters on CO and NO<SUB>x</SUB> emissions in a combustor operating in flameless combustion mode with kerosene fuel. Thermal input was varied in the range of 20–41kW (Heat release density ∼5–10MW/m<SUP>3</SUP>) with different fuel injectors and various fuel injection pressures. Spray parameters were varied by employing two separate conditions (i) same fuel flow rate with different solid cone pressure swirl spray nozzles (N1 – N4) and injection pressures (2.5–14bar) to achieve varying spray parameters at same thermal input (ii) same fuel injection nozzle at different fuel flow rates and injection pressures (5–13bar) to understand their effect on combustion and emissions. In both the cases, Sauter Mean Diameter (SMD) varied in the range of 34–58μm with spray cone angle varying from 42° to 56° using different nozzles and fuel injection pressures. Tangential air injection helped achieve higher recirculation of hot combustion products in the primary zone of the combustor for all thermal inputs. The finer sprays obtained at higher injection pressures helped achieve improved recirculation and better mixing, resulting in uniform temperature and hence reduced CO and NO<SUB>x</SUB> emissions. The measured CO and NO<SUB>x</SUB> emissions were in the range of 28–70ppm and 2–10ppm for all heat inputs with global equivalence ratio varying from ϕ=0.6 to 1, respectively. Measured acoustic emission levels were in the range of 98–101dB and 104–107dB for the flameless and transition mode respectively. The measured CO, NO<SUB>x</SUB> and acoustic emissions are an order of magnitude smaller those corresponding to conventional combustion mode. It was observed that coarser sprays led to a significant increase in acoustic emissions, relatively non-uniform temperature distribution and higher CO, NO<SUB>x</SUB> emissions during flameless combustion mode.</P>

Performance Analysis of IEEE 802.15.4/Zigbee Networks Under Route Information Based AODV Routing Algorithm

Rohit Ranjan,Harsukhpreet Singh,Anurag Sharma 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.12

In the field of wireless communication, zigbee is a latest technology in wireless network based on IEEE 802.15.4 standard. On IEEE 802.15.4 standard based zigbee network uses low power sensor nodes to ensure reliable, process, collect, and store the data. The sensor nodes have low cost, smaller in memory size and used in lower coverage area first two layers based on IEEE 802.15.4 standard are PHY and MAC layer. Routing protocols are divided in two categories that are reactive protocol and proactive protocol. AODV routing protocol comes under reactive protocol. It creates route between source and destination when needed. When source node has data to transmit to the destination node then it will create RREQ (route request message) and send to all neighbors in the network, when the destination node found or neighbor node found the route to destination then they will generate a RREP (route reply message) and forward back to source node. After the creation of route between source node and destination node they can exchange the data.

Seroprevalence of antibodies to SARS-CoV-2 and predictors of seropositivity among employees of a teaching hospital in New Delhi, India

Pragya Sharma,Rohit Chawla,Ritika Bakshi,Sonal Saxena,Saurav Basu,Pradeep Kumar Bharti,Meera Dhuria,S. K. Singh,Panna Lal 질병관리본부 2021 Osong Public Health and Research Persptectives Vol.12 No.2

Objectives: Healthcare workers (HCWs) are at a high risk of contracting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) due to the increased likelihood of clinical exposure during patient management. The study objective was to determine the seroprevalence of antibodies to SARS-CoV-2 and its predictors among hospital employees. Methods: The cross-sectional study was conducted at a teaching hospital from August 2020 to September 2020 among 1,401 employees, including 1,217 HCWs, in New Delhi, India. The serum samples were examined for immunoglobulin G (IgG) antibodies to SARS-CoV-2 using the COVID Kavach-Anti-SARS-CoV-2 IgG Antibody Detection enzyme-linked immunosorbent assay kit. Data were collected electronically using the EpiCollect mobile platform. A p<0.05 was considered to indicate statistical significance. Results: A total of 169 participants (12.1%) had detectable IgG antibodies to SARS-CoV-2. The highest seropositivity rate was observed in the administrative staff (20.1%), while it was lowest among medical doctors (5.5%, p<0.001). Male sex and ever having lived in a containment zone were independently associated with past infection with SARS-CoV-2. Conclusion: The seroprevalence of SARS-CoV-2 infection in health workers may be lower than in the general population in New Delhi. However, nonpharmaceutical interventions were not associated with a reduction in the risk of acquisition of SARS-CoV-2.

ON THE ENERGY OF MAXIMUM PRODUCTION OF INTERMEDIATE MASS FRAGMENTS IN HEAVY-ION COLLISIONS USING MICROSCOPIC MODEL

SAKSHI SHARMA,ROHIT KUMAR,RAJEEV K. PURI 장전수학회 2021 Proceedings of the Jangjeon mathematical society Vol.24 No.4

The present study is aimed to show the role played by impact parameter on the peak production of intermediate mass fragments (IMFs) in heavy-ion collisions. The study is conducted for both mass symmetric and mass asymmetric colliding nuclei. Here, the reactions are simulated using a Monte-Carlo based computer program developed utilizing the dynamical equations. Our present analysis shows that the impact parameter influences the reaction results on peak IMF production more drastically for mass asymmetric reactions than mass symmetric reactions.

The first record of European free-tailed bat, Tadarida teniotis Rafinesque, 1814, and note on probable elevational movement from Nepal

Basant Sharma,Rohit Chakravarty,Pushpa Raj Acharya 국립중앙과학관 2021 Journal of Asia-Pacific Biodiversity Vol.14 No.2

Out of the four Molossidae species from South Asia, the distribution of the European free-tailed bat,T. teniotis is most poorly known. This species has been occasionally reported from Afghanistan,Bangladesh, Bhutan, and India; however, no records exist in Nepal. Here we report the first record ofT. teniotis from Nepal and comment on its possible elevational movement in the Himalaya. Activeacoustic surveys were conducted in the Kali Gandaki canyon during autumn and winter seasons at twoelevational zones, 800e1200 m and 2100e2500 m, in three habitat types (forest, agricultural land, andhuman settlements). Echolocation calls of T. teniotis were easily distinguished by their low frequency,shallow frequency modulation, and long duration. During autumn, the activity was recorded only at 2100to 2500 m and varied significantly from winter activity, while T. teniotis was observed at both elevationalzones during winter. The result confirms the presence of T. teniotis from Nepal. Based on our observationsof differential activity at different elevation zones in two seasons, we recommend more intensive studiesto confirm seasonal migration and to understand seasonal demographics along the Kali Gandaki landscapeand in the entire Himalayan range at large.

Nutritional components as mitigators of cellular senescence in organismal aging: a comprehensive review

Bhawna Diwan,Rohit Sharma 한국식품과학회 2022 Food Science and Biotechnology Vol.31 No.9

The process of cellular senescence is rapidly emerging as a modulator of organismal aging and disease. Targeting the development and removal of senescent cells is considered a viable approach to achieving improved organismal healthspan and lifespan. Nutrition and health are intimately linked and an appropriate dietary regimen can greatly impact organismal response to stress and diseases including during aging. With a renewed focus on cellular senescence, emerging studies demonstrate that both primary and secondary nutritional elements such as carbohydrates, proteins, fatty acids, vitamins, minerals, polyphenols, and probiotics can influence multiple aspects of cellular senescence. The present review describes the recent molecular aspects of cellular senescence-mediated understanding of aging and then studies available evidence of the cellular senescence modulatory attributes of major and minor dietary elements. Underlying pathways and future research directions are deliberated to promote a nutrition-centric approach for targeting cellular senescence and thus improving human health and longevity.