Investigations on magnetic and electrical properties of Zn doped Fe₂O₃ nanoparticles and their correlation with local electronic structures

Kumar, Parmod,Sharma, Vikas,Singh, Jitendra P.,Kumar, Ashish,Chahal, Surjeet,Sachdev, K.,Chae, K.H.,Kumar, Ashok,Asokan, K.,Kanjilal, D. Elsevier 2019 Journal of magnetism and magnetic materials Vol.489 No.-

<P><B>Abstract</B></P> <P>Present work aims at investigating the structural, magnetic and dielectric properties of zinc doped Fe<SUB>2</SUB>O<SUB>3</SUB> nanoparticles (pure, 10%, 20% & 30%) and correlated with their local electronic structures using X-ray absorption near-edge structure (XANES) spectroscopy. X-ray diffraction and Raman measurements infer that doping of Zn cations lead to the formation of secondary phases corresponding to ZnFe<SUB>2</SUB>O<SUB>4</SUB> along with the hematite phase of Fe<SUB>2</SUB>O<SUB>3</SUB>. Magnetic measurements show that magnetization vs magnetic field curve for 10% Zn doping exhibit maximum saturation magnetization (~2.93 × 10<SUP>−3</SUP> emu/g) as well as the coercivity (~956 Oe). The values of these parameters decrease for higher content of Zn. The temperature dependence of dielectric behaviour follows the same trend as that of the lattice parameter and magnetic measurements. The XANES spectra at Fe L- and Fe K-edges indicate partial reduction of Fe<SUP>3+</SUP> ions into Fe<SUP>2+</SUP> upon Zn doping in the Fe<SUB>2</SUB>O<SUB>3</SUB> lattice. However, divalent state is favourable for Zn (i.e. Zn<SUP>2+</SUP>) within the doping range reported in this study.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Zn doped Fe<SUB>2</SUB>O<SUB>3</SUB> nanoparticles. </LI> <LI> Study of magnetic and electrical properties. </LI> <LI> Correlation of magnetic and electrical properties with local electronic structure. </LI> </UL> </P>

Cooperative Spectrum Sensing using Mobile Full-Duplex Cognitive Radio and Non-time-slotted Primary user Activity

Ashish K. Rao,Santoshkumar Sabat,Rajiv K. Singh,Neelam Srivastava 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.5

An In-band-full-duplex (FD) technology-empowered cognitive radio (CR) system with a non-time-slotted primary user activity is presented in this work. FD here means that the transmission and reception can be performed at the same frequency and time simultaneously. Moreover, to incorporate the mobility of the CR, the random waypoint model is used. The non-timeslotted primary user activity implies that the primary and the secondary network are not synchronized. Non-time-slotted means that the primary user can be active or inactive during the CR’s sensing/transmission duration. In the conventional time-slotted model, the primary user changes its state during the initial time and not later in the CR sensing window. The performance of the considered FD-CR network is observed in a Rayleigh fading environment. Specifically, the expression for miss-detection probability is derived. It is observed that the CR mobility and non-time-slotted primary activity would very much affect the miss-detection probability. Also, the proposed system with an efficient self-interference suppression mechanism outperforms the conventional half-duplex CRN.

Incorporation of Graphitic Porous Carbon for Synthesis of Composite Carbon Aerogel with Enhanced Electrochemical Performance

Singh, Ashish,Kohli, D.K.,Singh, Rashmi,Bhartiya, Sushmita,Singh, M.K.,Karnal, A.K. The Korean Electrochemical Society 2021 Journal of electrochemical science and technology Vol.12 No.2

We report, synthesis of high surface area composite carbon aerogel using additive based polymerization technique by incorporating graphitic porous carbon as additive. This additive was separately prepared using sol-gel polymerization of resorcinol-furfuraldehyde in iso-propyl alcohol medium at much above the routine gelation temperature to yield porous carbon (CA-IPA) having graphitic layered morphology. CA-IPA exhibited a unique combination of meso-pore dominated surface area (~ 700 m²/g) and good conductivity of ~ 300 S/m. The composite carbon aerogel (CCA) was synthesized by traditional aqueous medium based resorcinol-formaldehyde gelation with CA-IPA as additive. The presence of CA-IPA favored enhanced meso-porosity as well as contributed to improvement in bulk conductivity. Based on the surface area characteristics, CCA-8 composition having 8% additive was found to be optimum. It showed specific surface area of ~ 2056 m²/g, mesopore area of 827 m²/g and electrical conductivity of 180 S/m. The electrode formed with CCA-8 showed improved electrochemical behavior, with specific capacitance of 148 F/g & ESR < 1 Ω, making it a better choice as super capacitor for energy storage applications.

Patients with celiac disease are at high risk of developing metabolic syndrome and fatty liver

( Ashish Agarwal ),( Alka Singh ),( Wajiha Mehtab ),( Vipin Gupta ),( Ashish Chauhan ),( Mahendra Singh Rajput ),( Namrata Singh ),( Vineet Ahuja ),( Govind K. Makharia ) 대한장연구학회 2021 Intestinal Research Vol.19 No.1

Background/Aims: Gluten-free diet has an excess of fats and simple sugars and puts patients with celiac disease at risk of metabolic complications including metabolic syndrome and fatty liver. We assessed prevalence of metabolic syndrome and fatty liver in two cohorts of celiac disease. Methods: Study was done in 2 groups. In group 1, 54 treatment naïve patients with celiac disease were recruited. Of them, 44 returned after 1-year of gluten-free diet and were reassessed. In group 2, 130 celiac disease patients on gluten-free diet for ≥1 year were recruited. All patients were assessed for anthropometric and metabolic parameters and fatty liver. Metabolic syndrome was defined as per consensus definition for Asian Indians. Fatty liver was defined as controlled attenuation parameter value >263 decibels by FibroScan. Results: In group 1, of 44 treatment naïve patients with celiac disease, metabolic syndrome was present in 5 patients (11.4%) at baseline and 9 (18.2%) after 1 year of gluten-free diet. Patients having fatty liver increased from 6 patients (14.3%) at baseline to 13 (29.5%) after 1year of gluten-free diet (P=0.002). In group 2, of 130 patients with celiac disease on gluten-free diet for a median duration of 4 years, 30 out of 114 (26.3%) and 30 out of 130 patients (23%) had metabolic syndrome and fatty liver, respectively. Conclusions: Patients with celiac disease are at high risk of developing metabolic syndrome and fatty liver, which increases further with gluten-free diet. These patients should be assessed for nutritional and metabolic features and counseled about balanced diet and physical activity regularly. (Intest Res 2021;19:106-114)

Vibroacoustic analysis of stiffened functionally graded panels in thermal environments

Ashish K. Singh,Anwesha Pal,Shashi Kumar,Anuja Roy,Atanu Sahu 국제구조공학회 2024 Structural Engineering and Mechanics, An Int'l Jou Vol.89 No.5

Functionally graded materials (FGMs) have gained substantial attention from researchers due to their exceptional strength and thermal resistance. Their utilization in the aviation and automobile industries has significantly improved the efficiency of various structural components. Moreover, stiffened panels find wide applications in aerospace and automobile structures and these panels are frequently exposed to extreme environments. It is from this perspective that our research is focused on analysing the vibroacoustic response of stiffened functionally graded panels subjected to external dynamic excitations in a thermal environment. In the present research work, a finite element model is developed to conduct the dynamic analysis of functionally graded stiffened panels using the first-order shear deformation theory. Subsequently, a boundary element based model is also developed and coupled with the finite element model to investigate the sound radiation behaviour of those panels in a thermal environment. The material properties of FG stiffened panels are considered as temperature dependent, while the thermal environment is assumed to be acting as linearly varying through the panel’s thickness. The present investigation aim to compare the vibroacoustic responses of different panels due to stiffener orientations, material compositions, power law indices and plate thicknesses at various temperatures. The research findings highlight the significant impact of addition of stiffeners, its orientation and material compositions on the sound radiation characteristics of these panels under thermal environments. The present numerical model can easily be employed for analysing the sound radiation behaviour of other types of flat or curved stiffened panels having arbitrary geometry and boundary conditions.

Ruthenium doped carbon aerogel with CO2 surface activation for enhanced electrochemical capacitance

Ashish Singh,D.K. Kohli,Sushmita Bhartiya,Rashmi Singh,M.K. Singh,P.K. Gupta 한국물리학회 2017 Current Applied Physics Vol.17 No.6

With the aim of enhancement of electrochemical capacitance, CO2 activation of carbon aerogel (CA) prepared by polycondensation of resorcinol with formaldehyde was performed to obtain activated carbon aerogel (ACA) having improved surface area properties. Ruthenium oxide nano-particles were loaded by impregnation method for utilizing pseudo-capacitive property of ruthenium oxide (RuO2) and the effect of activation treatment was studied. RuO2 loading of 20% by weight was accomplished in CA and ACA to synthesize RuO2 doped carbon aerogel (CA/RuO2) and activated carbon aerogel (ACA/RuO2). While the specific capacitance of carbon aerogel improved from 95 to 153 F/g on activation, RuO2 loading further led to enhancement in capacitance and specific capacitance of 308 F/g was obtained for ACA/ RuO2. The studies being important for Ru economy, showed the influence of surface area enhancement of base matrix in achieving high specific capacitance.

Prediction of Hybrid Performance Based on the Genetic Distance of Parental Lines in Two-Line Rice (Oryza sativa L.) Hybrids

Singh, Vikas Kumar,Upadhyay, Priti,Sinha, Pallavi,Mall, Ashish Kumar,Ellur, Ranjith K.,Singh, Atul,Jaiswal, Sanjay K.,Biradar, Sunil,Ramakrishna, S.,Sundaram, R.M.,Ahmed, Ilyas,Viraktamath, B.C.,Kole, 한국작물학회 2011 Journal of crop science and biotechnology Vol.14 No.1

A total of six TGMS (thermosensitive genic male sterile lines) and nine pollinator lines were subjected to molecular characterization using 48 genome-wide SSR (simple sequence repeat) markers. Cluster analysis revealed clear differentiation among the TGMS lines according to their source of origin. The SSR-based genetic distance between the hybrids of the parental lines ranged from 0.36 to 0.79 suggesting a high degree of genetic divergence. Among a set of 54 hybrids generated using parental lines, 32 showed better parent heterosis (+21.7%) while 19 showed mid-parent heterosis (+15.0%). For the trait yield per plant genetic distance (GD) was negatively correlated with $F_1$ performance (r = -0.202), mid-parent heterosis (r = $-0.325^*$; P < 0.05), and better parent heterosis (r = -0.261), while it was positively correlated with specific combining ability (r = 0.042). Based on the grouped genetic distance (GGD), the hybrid combinations were divided into four groups. The GGD showed linear correlation with hybrid performance within the group (GGD = 40 - 50: r = -0.07; GGD = 70 - 80: r = 0.32). This information can be utilized in the development of higher yielding, two-line rice hybrids through selection of intermediately diverse parental lines using GGD.

The effect of attack of chloride and sulphate on ground granulated blast furnace slag concrete

Ashish, Deepankar K.,Singh, Bhupinder,Verma, Surender K. Techno-Press 2016 Advances in concrete construction Vol.4 No.2

This concrete is one of the most versatile construction material widely used for almost a century now. It was considered to be very durable material and required a little or no maintenance since long time. The assumption is very true, except when it is subjected to highly aggressive environments. The deterioration of concrete structures day by day due to aggressive environment is compelling engineers to assess the loss in advance so that proper preventive measure can be taken to achieve required durability to concrete structures. The compounds present in cement concrete are attacked by many salt solutions and acids. These chemicals are encountered by almost all concrete structures. The present study has been undertaken to investigate the effect of attack of chlorides and sulphates with varying severity on compressive strength of ground granulated blast furnace slag (GGBFS) concrete after immersion in salt solution for 28 days. The results indicate that the durability of GGBFS concrete increases with the increase in percentage replacement of cement by GGBFS for 20% and then gradually decreases with increases in percentage of GGBFS with cement (as in the study for 40% and 60%). Also there is increase in strength of GGBFS concrete with increase in age. Thus the durability of concrete improves when GGBFS is added as partial replacement of cement. In this study the strength of GGBFS concrete is less affected by chemicals as compared to conventional concrete when exposed to aggressive environment.

Prediction of Hybrid Performance Based on the Genetic Distance of Parental Lines in Two-Line Rice (Oryza sativa L.) Hybrids

Vikas Kumar Singh,Priti Upadhyay,Pallavi Sinha,Ashish Kumar Mall,Ranjith K. Ellur,Atul Singh,Sanjay K.Jaiswal,Sunil Biradar,S. Ramakrishna,R.M. Sundaram,Ilyas Ahmed,B. C. Viraktamath,C. Kole,Sukhpal S 한국작물학회 2011 Journal of crop science and biotechnology Vol.14 No.1

A total of six TGMS (thermosensitive genic male sterile lines) and nine pollinator lines were subjected to molecular characterization using 48 genome-wide SSR (simple sequence repeat) markers. Cluster analysis revealed clear differentiation among the TGMS lines according to their source of origin. The SSR-based genetic distance between the hybrids of the parental lines ranged from 0.36to 0.79 suggesting a high degree of genetic divergence. Among a set of 54 hybrids generated using parental lines, 32 showed better parent heterosis (+21.7%) while 19 showed mid-parent heterosis (+15.0%). For the trait yield per plant genetic distance (GD) was negatively correlated with F1 performance (r = -0.202), mid-parent heterosis (r = -0.325*; P < 0.05), and better parent heterosis (r = -0.261), while it was positively correlated with specific combining ability (r = 0.042). Based on the grouped genetic distance (GGD),the hybrid combinations were divided into four groups. The GGD showed linear correlation with hybrid performance within the group (GGD = 40 - 50: r = -0.07; GGD = 70 - 80: r = 0.32). This information can be utilized in the development of higher yielding,two-line rice hybrids through selection of intermediately diverse parental lines using GGD.

Axial Segregation in Horizontally Vibrated Granular Materials: A Numerical Study

Ashish Bhateja,Jayant K. Singh,Ishan Sharma 대한토목학회 2009 KSCE JOURNAL OF CIVIL ENGINEERING Vol.13 No.4

It is known that a horizontally vibrated binary mixture in a tapered and inclined channel segregates axially, with the two species moving to the opposite ends of the channel. In general, the parameters that affect the segregation process include the forcing frequency and its amplitude, the constituents’ mass and size, and the taper and inclination of the channel. The ultimate goal here is to locate those parameters that are most significant to the segregation process, thereby providing control variables for practical applications. However, owing to the complexity of the problem, as a first step to better understand the physics behind this phenomenon, we undertake three dimensional molecular dynamics simulations of a horizontally vibrated mono-disperse granular particles in a tapered and inclined channel. Though at this stage, the immediately addressed problem is of more relevance to the granular material industry, it is envisaged that tools developed to understand this process will ultimately have wide applicability to granular systems, occurring in both natural contexts and in geotechnical engineering. It is known that a horizontally vibrated binary mixture in a tapered and inclined channel segregates axially, with the two species moving to the opposite ends of the channel. In general, the parameters that affect the segregation process include the forcing frequency and its amplitude, the constituents’ mass and size, and the taper and inclination of the channel. The ultimate goal here is to locate those parameters that are most significant to the segregation process, thereby providing control variables for practical applications. However, owing to the complexity of the problem, as a first step to better understand the physics behind this phenomenon, we undertake three dimensional molecular dynamics simulations of a horizontally vibrated mono-disperse granular particles in a tapered and inclined channel. Though at this stage, the immediately addressed problem is of more relevance to the granular material industry, it is envisaged that tools developed to understand this process will ultimately have wide applicability to granular systems, occurring in both natural contexts and in geotechnical engineering.