Synthesis, structural and optical characterization of nanocrystalline ZnS:Cu embedded in silica matrix

Ashish Tiwari,S.A. Khan,R.S. Kher 한국물리학회 2012 Current Applied Physics Vol.12 No.3

The synthesis of Cu doped ZnS nanoparticles inside the pore of an inorganic silica gel matrix is presented. The synthesized nanoparticles were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). X-ray diffraction pattern reveals the crystalline wurtzite phase of ZnS. The existence of silica gel in modeling morphologies of the nanoparticles was characterized using Fourier transform infrared (FTIR) spectrometer. Thickness of the silica shell was also calculated. UV- absorption spectrum shows the appearance of an absorption peak at 273 nm which confirms the blue shift as compared to that of bulk ZnS. The photoluminescence (PL) emission spectrum of the sample showed a broad band in the range 465e510 nm due to the transition from the conduction band edge of ZnS nanocrystals to the acceptor like t2 state of Cu. The synthesis of Cu doped ZnS nanoparticles inside the pore of an inorganic silica gel matrix is presented. The synthesized nanoparticles were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). X-ray diffraction pattern reveals the crystalline wurtzite phase of ZnS. The existence of silica gel in modeling morphologies of the nanoparticles was characterized using Fourier transform infrared (FTIR) spectrometer. Thickness of the silica shell was also calculated. UV- absorption spectrum shows the appearance of an absorption peak at 273 nm which confirms the blue shift as compared to that of bulk ZnS. The photoluminescence (PL) emission spectrum of the sample showed a broad band in the range 465e510 nm due to the transition from the conduction band edge of ZnS nanocrystals to the acceptor like t2 state of Cu.

Design and Analysis of Various Characteristics of a MEMS-Based PIB/CNT/LiNbO3 Multilayered SAW Sensor for CO2 Gas Detection

Ashish Tiwary,Shasanka Sekhar Rout,Basudeba Behera 한국전기전자재료학회 2022 Transactions on Electrical and Electronic Material Vol.23 No.6

This paper presents the design and analysis of a surface acoustic wave (SAW) sensor with a multilayer nanocomposite to detect carbon dioxide (CO2) gas. SAW resonator impacts the detection and identifi cation of hazardous gases that exist in the environment in an uncontrolled manner. These devices have the operational capability to work in a very extreme elevated temperature, pressure, and inert noxious atmosphere. The proposed work is intended to provide a two-dimensional model of a surface acoustic wave device/sensor and the most prominent solid material, carbon nanotube (CNT), which plays a vital role in the adsorption of volatile organic compounds. However, another miniature sensor has been designed with a potential material, an organic polymer, i.e., poly-isobutylene (PIB). Both the sensor model responses were examined for CO2 gas at room temperature. In this work, we have designed two diff erent resonator structures with the help of COMSOL Multiphysics. The proposed, designed models were patterned with interdigitated transducer electrodes made of aluminum material coated explicitly on top of the structure were used to analyze gas sensing behavior for CO2 gaseous elements. Here the proposed geometry provides resonance of 9.1524 MHz and anti-resonance of 9.2455 MHz for monolayer structure and resonance of 8.6447 MHz, and anti-resonance of 8.5201 MHz for multilayer structure. Comparatively, the second sensor PIB/CNT/LiNbO3 heterostructure pattern was also designed to be the best choice for the accurate and reliable measurement of the concentration of various gaseous elements based on a few parameters are discussed further.

An Unusual Presentation of Rectal Carcinoma in a Child

Tiwari, Charu,Zadpe, Ashish,Rathi, Pravin,Shah, Hemanshi The Korean Society of Pediatric Gastroenterology 2018 Pediatric gastroenterology, hepatology & nutrition Vol.21 No.1

Colorectal carcinoma is a well-known malignancy in adults. However, it is rare in children. Besides, it also has different behaviour in paediatric age-group and usually presents with non-specific symptoms like abdominal pain, weight loss, and anaemia. This usually leads to delay in diagnosis. Adenocarcinoma in children has unfavourable tumour histology (mucinous subtype) and advanced disease stage at presentation which lead to poorer prognosis in children. Family history, genetic typing and sibling screening are essential components of management as this malignancy is frequently seen associated with hereditary syndromes. We describe a case of unusual presentation of rectal carcinoma in a 12-year-old girl.

A unified framework for operational range estimation of mobile robots operating on a single discharge to avoid complete immobilization

Tiwari, Kshitij,Xiao, Xuesu,Malik, Ashish,Chong, Nak Young Elsevier 2019 Mechatronics Vol.57 No.-

<P><B>Abstract</B></P> <P>Mobile robots are being increasingly deployed in fields where human intervention is deemed risky. However, in doing so, one of the prime concern is to prevent complete battery depletion which may in turn lead to immobilization of the robot during the mission. Thus, we need to carefully manage the energy available to explore as much of the unknown environment as feasible whilst guaranteeing a safe return journey to home base. For this, we need to identify the key components that draw energy and quantify their individual energy requirements. However, this problem is difficult due to the fact that most of the robots have different motion models, and the energy consumption usually also varies from mission to mission. It is desirable to have a generic framework that takes into account different locomotion models and possible mission profiles. This paper presents a methodology to unify the energy consumption models for various robotic platforms thereby allowing us to estimate operational range in both offline and online fashions. The existing models consider a given mission profile and try to estimate its energy requirements whilst our model considers the energy as a given resource constraint and tries to optimize the mission to be accomplished within these constraints. The proposed unified energy consumption framework is verified by field experiments for micro UGV and multi-rotor UAV test-beds operating under myriad of environmental conditions. The <I>online</I> model estimates operational range with an average accuracy (measured with respect to true range across multiple field trials) of 93.87% while the <I>offline</I> model attains 82.97%.</P>

An Unusual Presentation of Rectal Carcinoma in a Child

Charu Tiwari,Ashish Zadpe,Pravin Rathi,Hemanshi Shah 대한소아소화기영양학회 2018 Pediatric gastroenterology, hepatology & nutrition Vol.21 No.1

Colorectal carcinoma is a well-known malignancy in adults. However, it is rare in children. Besides, it also has different behaviour in paediatric age-group and usually presents with non-specific symptoms like abdominal pain, weight loss, and anaemia. This usually leads to delay in diagnosis. Adenocarcinoma in children has unfavourable tumour histology (mucinous subtype) and advanced disease stage at presentation which lead to poorer prognosis in children. Family history, genetic typing and sibling screening are essential components of management as this malignancy is frequently seen associated with hereditary syndromes. We describe a case of unusual presentation of rectal carci-noma in a 12-year-old girl.

Plant Diversity, Tree Regeneration, Biomass Production and Carbon Storage in Different Oak Forests on Ridge Tops of Garhwal Himalaya

Sharma, Chandra Mohan,Tiwari, Om Prakash,Rana, Yashwant Singh,Krishan, Ram,Mishra, Ashish Kumar Institute of Forest Science 2016 Journal of Forest Science Vol.32 No.4

The present study was conducted on ridge tops of moist temperate Oak forests in Garhwal Himalaya to assess the plant diversity, regeneration, biomass production and carbon assimilation in different Oak forests. For this purpose, three Oak forest types viz., (a) Quercus leucotrichophora or Banj Oak (FT1; between 1,428-2,578 m asl), (b) Quercus floribunda or Moru Oak (FT2; between 2,430-2,697 m asl) and (c) Quercus semecarpifolia or Kharsu Oak (FT3; between 2,418-3,540 m asl) were selected on different ridge tops in Bhagirathi catchment area of Garhwal Himalaya. A total of 91 plant species including 23 trees (8 gymnosperms and 15 angiosperms), 21 shrubs and 47 herbs species belonging to 46 families were recorded from all the ridge top Oak forests. The highest mean tree density ($607{\pm}33.60trees\;ha^{-1}$) was observed in Q. floribunda forest with lower mean total basal cover (TBC) value ($48.02{\pm}3.67m^2ha^{-1}$), whereas highest TBC value ($80.16{\pm}3.30m^2ha^{-1}$) was recorded for Q. semecarpifolia forest, with lowest mean stem density ($594{\pm}23.43stems\;ha^{-1}$). The total biomass density (TBD) across three Oak forests ranged between $497.32{\pm}83.70$ (FT1) and $663.16{\pm}93.85t\;ha^{-1}$ (FT3), while the total carbon density (TCD) values ranged between $228.75{\pm}22.27$ (FT1) and $304.31{\pm}18.12t\;ha^{-1}$ (FT3). Most of the tree species were found with good regeneration (GR) status (average 45%) in all the forest types whereas, few species were found not regenerating (NR) (average 17%) however, few new recruitments were also recorded. ANOVA (Post-Hoc Tukey's test at 5% significance level) indicated significant forest-wise differences in TBC, TBD and TCD (in tree layer); family and evenness (in shrub layer only) values, while insignificant differences were noticed in density values of tree, seedling and herb layer.

Option Strategies: An Analysis of Naked Put Writing

Lekvin Brent J.,Tiwari Ashish Korean Financial Management Association 1996 財務管理論叢 Vol.3 No.2

Writing naked put options is a strategy employed either as a speculation to capture premium income, or as a method of placing a limit order to buy the underlying at the strike price in return for premium received. Using a Monte Carlo simulation, twenty thousand equity prices are generated under known volatility and return parameters. A binomial tree is constructed using the same volatility and return parameters. Put options on these 'equities' are valued with the binomial methodology. The performance of various put writing strategies is evaluated on a risk-adjusted basis. Evidence presented suggests that the judicious use of put options may enhance returns during portfolio construction.

Plant Diversity, Tree Regeneration, Biomass Production and Carbon Storage in Different Oak Forests on Ridge Tops of Garhwal Himalaya

Chandra Mohan Sharma,Om Prakash Tiwari,Yashwant Singh Rana,Ram Krishan,Ashish Kumar Mishra 강원대학교 산림과학연구소 2016 Journal of Forest Science Vol.32 No.4

The present study was conducted on ridge tops of moist temperate Oak forests in Garhwal Himalaya to assess the plant diversity, regeneration, biomass production and carbon assimilation in different Oak forests. For this purpose, three Oak forest types viz., (a) Quercus leucotrichophora or Banj Oak (FT1; between 1,428-2,578 m asl), (b) Quercus floribunda or Moru Oak (FT2; between 2,430-2,697 m asl) and (c) Quercus semecarpifolia or Kharsu Oak (FT3; between 2,418-3,540 m asl) were selected on different ridge tops in Bhagirathi catchment area of Garhwal Himalaya. A total of 91 plant species including 23 trees (8 gymnosperms and 15 angiosperms), 21 shrubs and 47 herbs species belonging to 46 families were recorded from all the ridge top Oak forests. The highest mean tree density (607±33.60 trees ha-1) was observed in Q. floribunda forest with lower mean total basal cover (TBC) value (48.02± 3.67 m2ha-1), whereas highest TBC value (80.16±3.30 m2ha-1) was recorded for Q. semecarpifolia forest, with lowest mean stem density (594±23.43 stems ha-1). The total biomass density (TBD) across three Oak forests ranged between 497.32±83.70 (FT1) and 663.16±93.85 t ha-1 (FT3), while the total carbon density (TCD) values ranged between 228.75±22.27 (FT1) and 304.31±18.12 t ha-1 (FT3). Most of the tree species were found with good regeneration (GR) status (average 45%) in all the forest types whereas, few species were found not regenerating (NR) (average 17%) however, few new recruitments were also recorded. ANOVA (Post-Hoc Tukey’s test at 5% significance level) indicated significant forest-wise differences in TBC, TBD and TCD (in tree layer); family and evenness (in shrub layer only) values, while insignificant differences were noticed in density values of tree, seedling and herb layer.