Highly Efficient Photocatalytic Studies on Bi36 Fe2 O57 Ceramic Synthesized by Chemical Route

Manish Kumar Verma,Vinod Kumar,Upakar Patel,Vishnu Shankar Rai,Anup Kumar,Arup Kumar De,Aditya Kumar Prajapati,Dinesh Prajapati,Kedar Sahoo,Tapas Das,N. B. Singh,K. D. Mandal 한국전기전자재료학회 2023 Transactions on Electrical and Electronic Material Vol.24 No.5

Bi36 Fe2 O57 (BFO) polycrystalline ceramic was synthesized by economical chemical route. The single-phase formation of BFO ceramic was confirmed by powder X-ray diffraction studies. Nanosized formation of BFO ceramics established by XRD and TEM analysis. The bimodal distribution of grain size is observed with size ranging from 50 to 600 nm. It observed that the Bi36 Fe2 O57 photocatalyst exhibited higher catalytic activity for the degradation of Methylene Blue (MB) under visible-light irradiation The oxidation state of elements present in the BFO ceramic, was confirmed by XPS studies. The pseudocapacitive nature of BFO ceramic was observed by cyclic Voltammetry. The dielectric constant of BFO ceramic was found 375 at 1 kHz at 300 K. The dielectric loss was found 0.51 at 100 kHz and 300 K.

Role of low energy transition metal ions in interface formation in ZnO thin films and their effect on magnetic properties for spintronic applications

Bhardwaj, Richa,Kaur, Baljeet,Singh, Jitendra Pal,Kumar, Manish,Lee, H.H.,Kumar, Parmod,Meena, R.C.,Asokan, K.,Hwa Chae, Keun,Goyal, Navdeep,Gautam, Sanjeev Elsevier 2019 APPLIED SURFACE SCIENCE - Vol.479 No.-

<P><B>Abstract</B></P> <P>In this study, X-ZnO/ZnO/Si(100) (X = Co, Ni and Cu) bilayer structure is fabricated using low energy ion implantation technique. Five different fluences 1 × 10<SUP>15</SUP>, 5 × 10<SUP>15</SUP>, 1 × 10<SUP>16</SUP>, 2.5 × 10<SUP>16</SUP> and 5 × 10<SUP>16</SUP> ions/cm<SUP>2</SUP> with 100 keV ion-beam energy were selected in order to implant the ions up to the depth of ≈44 nm as calculated through Stopping Range of Ion in Matter and Transport Range of Ions in Matter software. Structural modification was investigated by high resolution X-ray diffraction measurements in ZnO bilayer system. An observed systematic 2<I>θ</I> shift in (002) peak with increasing fluence implies increased density of implanted metal ions in ZnO matrix revealing the substitution of implanted ion at Zn-site. The mechanism of bilayer formation by ion-beam implantation technique has been discussed for metal-ions by investigating their interface properties. Atomic force microscopy reveals the morphological modification after ion implantation. Near-edge X-ray absorption fine-structure (NEXAFS) measurements at metal <I>K</I>- and <I>L</I> <SUB>3,2</SUB>-edges have been used to investigate the nature of implanted ions in terms of their valance state and local electronic environment. Further, O <I>K</I>-edge NEXAFS measurement for Ni-ZnO/ZnO/Si bilayer is highly sensitive to incident beam angles whereas no spectral change is seen for Zn <I>L</I>-edge measurements. The magnetic measurements were performed via vibrating sample magnetometer that showed the films are ferromagnetic at room temperature. The origin of ferromagnetism has been understood through defect mediated bound magnetic polaron model. Further, perpendicular magnetic anisotropy is also observed for Ni-ZnO/ZnO/Si bilayer structure at room temperature, which is correlated with the angle dependent O K-edge NEXAFS measurements. Fabrication of ZnO bilayer via ion implantation and investigation of above properties may prove useful in spin related and optoelectronic applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Observance of RTFM in metal ion-implanted Ni-ZnO/ZnO/Si bilayer </LI> <LI> HRXRD and NEXAFS measurements confirms the wurtzite phase and Zn<SUP>2+</SUP> substitution in ZnO matrix. </LI> <LI> Angle dependent NEXAFS measurements provides the evidence of observed PMA. </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>Mechanism of ion beam interaction X (X = Co, Ni and Cu) with ZnO lattice forming X-ZnO/ZnO/Si(100) bilayer structure. Films were implanted using a multi cathode source of negative-ions by cesium sputtering (MC-SNICS) and with the increasing ion flux, X can undergo one of two mechanisms of either substituting the Zn-site or occupy interstitial position in ZnO matrix. Angle dependent O K-edge NEXAFS measurements provides the evidence of perpendicular magnetic anisotropy in ZnO bilayer. </P> <P>[DISPLAY OMISSION]</P>

Novel conducting lithium ferrite/chitosan nanocomposite: Synthesis, characterization, magnetic and dielectric properties

Manish Srivastava,Jay Singh,Rajneesh K. Mishra,Manish K. Singh,Animesh K. Ojha,Madhu Yashpal,Srivastava Sudhanshu 한국물리학회 2014 Current Applied Physics Vol.14 No.7

A study on Lithium ferrite/chitosan nanocomposite (LFCN), easily moldable into arbitrary shapes, as the conducting polymer and ferromagnetic characteristics is presented. The composite material is produced in the presence of Li0.5Cr0.1Fe2.4O4 and Li0.5Co0.1Fe2.4O4 nanoparticle by ex-situ polymerizations process. Various characterizations techniques have been used to explore the characteristic of the synthesized products. The frequency dependent dielectric properties and electrical conductivity of all the samples have been measured through complex impedance plot in the frequency range of 1 kHze6 MHz at room temperature. It was observed that in case of (LFCN), fluctuation in value of (ε 0) and (ε 00) is ceased over the frequency range of 4 Mz which can be attributed to the steady storage and dissipation of energy in the nanocomposite system. Moreover, it is also observed that electrical conductivity of (LFCN) increases with frequency and its value was found to be (0.032e0.048) (ohm-cm)1 in frequency range of 1 kHze6 MHz. Due to its low cost, a simple synthesis process and high flexibility, the proposed LFCN may find applications in various types of electronic components.

Microwave-Assisted Synthesis of Boron and Nitrogen co-doped Reduced Graphene Oxide for the Protection of Electromagnetic Radiation in Ku-Band

Umrao, Sima,Gupta, Tejendra K.,Kumar, Shiv,Singh, Vijay K.,Sultania, Manish K.,Jung, Jung Hwan,Oh, Il-Kwon,Srivastava, Anchal American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.35

<P>The electromagnetic interference (EMI) shielding of reduced graphene oxide (MRG), B-doped MRG (BMRG), N-doped MRG (N-MRG), and B-N co-doped MRG (B-N-MRG) have been studied in the Ku-band frequency range (12.8-18 GHz). We have developed a green, fast, and cost-effective microwave assisted route for synthesis of doped MRG. B-N-MRG shows high electrical conductivity in comparison to MRG, B-MRG and N-MRG, which results better electromagnetic interference (EMI) shielding ability. The co-doping of B and N significantly enhances the electrical conductivity of MRG from 21.4 to 124.4 Sm-1 because N introduces electrons and B provides holes in the system and may form a nanojunction inside the material. Their temperature-dependent electrical conductivity follows 2D-variable range hopping (2D-VRH) and Efros-Shldovskii-VRH (ES-VRH) conduction model in a low temperature range (T < 50 K). The spatial configuration of MRG after doping of B and N enhances the space charge polarization, natural resonance, dielectric polarization, and trapping of EM waves by internal reflection leading to a high EMI shielding of -42 dB (-99.99% attenuation) compared to undoped MR.G (-28 dB) at a critical thickness of 1.2 mm. Results suggest that the B-N-MRG has great potential as a candidate for a new type of EMI shielding material useful in aircraft, defense industries, communication systems, and stealth technology.</P>

Butterfly communities along an elevational gradient in the Tons valley, Western Himalayas: Implications of rapid assessment for insect conservation

Manish Bhardwaj,Abesh K. Sanyal,Arun P. Singh,V.P. Uniyal 한국응용곤충학회 2012 Journal of Asia-Pacific Entomology Vol.15 No.2

As time and money is limited, explicit, cost-effective, quick, and appropriate methods are needed to assist conservation planners and managers for making quick decisions. Butterflies promise to be a good model for rapid assessment and habitat monitoring studies because they are widespread, conspicuous, and easily recognizable and they are effective indicators of forest health. We conducted a rapid assessment of butterflies at five disturbance gradient sites that varied in elevation from 900 m a.s.l. to 3500 m a.s.l. for 20 days during March–April 2010 and recorded 79 butterfly species and 1504 individuals in the Tons valley in Western Himalayas. We were able to sample approximately 77% (123 species) of the estimated species richness on continuing the sampling until July 2010. Species richness at the study site is estimated to be 159 (95% CI:145–210) species. Diversity was highest in heterogeneous habitats and decreased towards homogeneous habitats. Unique species were highly restricted to lowest disturbed sites. Using Pearson's correlation analysis,the strongest vegetative predictors of butterfly richness were plant species richness, canopy cover, and herb and shrub density. Butterfly species richness and abundance were highly correlated with altitude, temperature,relative humidity, fire signs, and livestock abundance. We also found positive cross-taxon correlation among butterflies, moths, and beetles across sites, indicating that butterflies can be used as surrogate or indicator taxa for insect conservation. Short sampling periods providing comprehensive estimates of species richness were reliable for identifying habitats and sites with the most conservation value in the Tons valley landscape.

Psychiatric, Somatic and Other Functional Gastrointestinal Disorders in Patients With Irritable Bowel Syndrome at a Tertiary Care Center

( Prashant Singh ),( Abhishek Agnihotri ),( Manish K Pathak ),( Asef Shirazi ),( Rajeew P Tiwari ),( V Sreenivas ),( Rajesh Sagar ),( Govind K Makharia ) 대한소화기기능성질환·운동학회 2012 Journal of Neurogastroenterology and Motility (JNM Vol.18 No.3

Background/Aims To study the prevalence of somatic and psychiatric co-morbidities in the patients of irritable bowel syndrome (IBS) and to assess the quality of life (QOL) of these patients. Methods One hundred and eighty-four IBS patients and 198 controls were included. Diagnosis of IBS, its sub-classification and assessment of other functional gastrointestinal disorders (FGIDs) was made on basis of Rome III criteria. Severity of IBS was assessed using IBS severity scoring system. Psychiatric evaluation was done using Patient Heath Questionnaire. QOL was evaluated using WHO QOL-BREF. Results One hundred and forty-seven (79.9%) and 158 (85.9%) patients with IBS had at least one other FGID or at least one somatic co-morbidity, respectively. Higher number of patients had at least one psychiatric co-morbidity compared to controls (79.9% vs 34.3%; P < 0.001). Major depressive syndrome (47.3% vs 5.1%; P < 0.001), somatoform disorder (50% vs 14.6%; P < 0.001) and panic syndrome (44% vs 11.6%; P < 0.001) were more common in IBS than controls. Only 14 (7.6%) patients were receiving drug treatment for their psychiatric illness. Severe IBS symptoms were present in significantly higher number of patients with constipation predominant IBS than diarrhea predominant IBS. Those with severe disease had higher prevalence of psychiatric (95.1%) and somatic (96.7%) co-morbidities compared with mild disease. QOL of IBS patients was significantly lower in all four domains compared to controls. Presence of at least one other FGID was significantly associated with presence of one or more psychiatric co-morbidity (P < 0.001). Conclusions Majority of IBS patients presenting to a tertiary care center had associated psychiatric, somatic co-morbidities and reduced QOL. Very few of them received specific psychiatric treatment. (J Neurogastroenterol Motil 2012;18:324-331)

Recent advances in graphene and its metal-oxide hybrid nanostructures for lithium-ion batteries

Srivastava, Manish,Singh, Jay,Kuila, Tapas,Layek, Rama K.,Kim, Nam Hoon,Lee, Joong Hee The Royal Society of Chemistry 2015 Nanoscale Vol.7 No.11

<P>Today, one of the major challenges is to provide green and powerful energy sources for a cleaner environment. Rechargeable lithium-ion batteries (LIBs) are promising candidates for energy storage devices, and have attracted considerable attention due to their high energy density, rapid response, and relatively low self-discharge rate. The performance of LIBs greatly depends on the electrode materials; therefore, attention has been focused on designing a variety of electrode materials. Graphene is a two-dimensional carbon nanostructure, which has a high specific surface area and high electrical conductivity. Thus, various studies have been performed to design graphene-based electrode materials by exploiting these properties. Metal-oxide nanoparticles anchored on graphene surfaces in a hybrid form have been used to increase the efficiency of electrode materials. This review highlights the recent progress in graphene and graphene-based metal-oxide hybrids for use as electrode materials in LIBs. In particular, emphasis has been placed on the synthesis methods, structural properties, and synergetic effects of metal-oxide/graphene hybrids towards producing enhanced electrochemical response. The use of hybrid materials has shown significant improvement in the performance of electrodes.</P>

Mass Transfer Studies on Ternary Systems in a Bench-scale Liquid-Liquid Extraction (LLX) Column and a Comparison with Simulations

Sanpui, Debjit,Singh, Manish K.,Khanna, Ashok 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.2

Mass transfer studies in a laboratory scale extraction column have been conducted for Toluene-Acetone-Water and MIBK-Acetic Acid-Water systems. From these experiments stage-wise solute(Acetone or Acetic-Acid)composition profiles have been obtained for both dispersed and continuous phase. These composition profiles have been compared with those obtained from ASPENLUS, CHEMSEP and LLXSIM simulators. For liquid0liquid equilibrium caculations all these simulators use UNIFAC and UNIQUAC model. The binary interaction parameters for the UNIFAC are inbulit in ASPENPLUS and CHEMSEP, UNIQUAC binary parameters were borrowed from DECHEMA. Error square analysis indicates that simulations based on non-equilibrium option of LLXSIM match closely with experimental results. Temperature profiles and hydrodynamic features characterized by number of drops and static holdup on the stages have been compared between the LLXSIM simulated and the experimental results and these match well. However simulations in ASPENPLUS give sum of relative error-squares for all experimental runs at least len times higher, in spite of tuning the average stage efficiency.

SnO2 quantum dots decorated on RGO: a superior sensitive, selective and reproducible performance for a H2 and LPG sensor.

Mishra, R K,Upadhyay, S B,Kushwaha, Ajay,Kim, Tae-Hyung,Murali, G,Verma, Ranjana,Srivastava, Manish,Singh, Jay,Sahay, P P,Lee, Seung Hee RSC Pub 2015 Nanoscale Vol.7 No.28

<P>We report the H2 and LPG gas sensing behavior of RGO/SnO2 QDs synthesized by a surfactant assisted hydrothermal method. The RGO/SnO2 QD based sensor shows a high response of 89.3% to H2 and 92.4% to LPG for 500 ppm test gas concentration at operating temperatures of 200 C and 250 C, respectively. Further, the RGO/SnO2 QD based sensor shows good selectivity for H2 and LPG in the presence of other interfering gases such as ammonia, chloroform, toluene, benzene, acetone, n-butylacetate, acetic acid and formic acid. We observed that the gas response to H2 is 29.8 times higher than that to acetic acid whereas the gas response to LPG is 17.8 times higher than that to formic acid. Long-term analyses have also been performed to demonstrate the reproducible nature of the RGO/SnO2 QD based sensor over passing time which shows excellent reproducibility.</P>

Mass Transfer Studies on Ternary Systems in a Bench-scale Liquid-Liquid Extraction (LLX) Column and a Comparison with Simulations

Ashok Khanna,Debjit Sanpui,Manish K. Singh 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.2

Mass transfer studies in a laboratory scale extraction column have been conducted for Toluene-Acetone-Water and MIBK-Acetic Acid-Water systems. From these experiments stage-wise solute (Acetone or Acetic-Acid)composition profiles have been obtained for both dispersed and continuous phase. These composition profiles havebeen compared with those obtained from ASPENPLUS, CHEMSEP and LLXSIM simulators. For liquid-liquid equilib-rium calculations all these simulators use UNIFAC and UNIQUAC model. The binary interaction parameters for theUNIFAC are inbuilt in ASPENPLUS and CHEMSEP. UNIQUAC binary parameters were borowed from DECHEMA.Eror square analysis indicates that simulations based on non-equilibrium option of LLXSIM match closely withexperimental results. Temperature profiles and hydrodynamic features characterized by number of drops and staticholdup on the stages have been compared between the LLXSIM simulated and the experimental results and these matchwel. However simulations on ASPENPLUS give sum of relative error-squares for all the experimental runs at least tentimes higher, in spite of tuning the average stage efficiency.