041357   MOZAFFARI A, MIRJALILI M, GASHTI M P, PARSANIA M (Textile Engineering Dep, Islamic Azad Univ, Yazd, Iran, Email: dr.mirjalili@iauyazd.ac.ir) : Effect of tannic acid on properties of electrospun gelatin nanofibres. Indian J Fibre Text Res 2020, 45(2), 153-63.

Gelatin/tannic acid nanofibres have been prepared and the effects of production parameters, including high voltage, feeding rate and distance between tip of the needle and collector on the morphology of nanofibres are investigated. The results show that the average nanofibre diameter increases with raising the high voltage values, due to less branching of liquid jet. Increasing the feeding rate leads to an increase in the nanofibre diameter, up to a certain value (0.6-0.8 mL/h). Further increase in the feeding rate value causes the formation of a ribbon-like structure. The increment in the content of tannic acid as a crosslinker increases the viscosity of the spinning solution and the average nanofibre diameters. Also, the tensile strength of crosslinked nanofibres increases as compared to that of the gelatin nanofibres. Moreover, the addition of tannic acid to gelatin nanofibres significantly enhances the antibacterial property of nanofibres.

7 illus, 1 table, 45 ref

041309   NAG A, SRIVASTAVA A K, DIXIT A R, MANDAL A, DAS A K (G L Bajaj Institute of Technology and Management, Greater Noida, Gautam Budha Nagar - 201 306, Email: ashish7185@gmail.com) : Study of surface integrity and effect of process parameters in wire electrical discharge turning of Ti-6Al-4V. Indian J Eng Mater Sci 2020, 27(2), 267-76.

Wire electrical discharge turning set-up has been developed by modifying the conventional five axes CNC WEDM machine. The main objective of this setup is to achieve cylindrical forms on hard to cut materials. This work focuses on the study of effect of input process parameters like pulse on-time, pulse off time, gap voltage, spindle rotational speed on output responses like surface roughness, material removal rate and wire wear ratio. A mathematical model of responses has been developed using response surface methodology and the optimal value of process parameters has been obtained by desirability function. Surface morphology studies of the machined surface and the worn-out wire has also been elaborated by FE-SEM images. The results show that with an increase in machining parameters value except pulse-on time, all the desired machining outcome decreases. Surface roughness, material removal rate and wire wear ratio have been found in the range of 1.99 µm – 1.37 µm, 7.55 – 13.66 mm³/min and 0.05–0.08, respectively. The formation of thick recast layer over the machined surface has also been discussed. The reduction in wire dimension has been calculated by optical microscopy and its morphology has been discussed by FE-SEM images.

11 illus, 7 tables, 46 ref

042826   MAHEWAR R B , RAVANGAVE L S (Physics Dep, Shri Sant Gadge Maharaj Coll, Loha Dist, Nanded, Email: lsravangave@gmail.com) : Structure, morphology and optical parameters of spray deposited CZTS thin films for solar cell applications. Indian J Sci Technol 2020, 13(21), 2149–56.

To develop simple method for Cu₂ZnSnS₄ (CZTS) thin film deposition suitable for solar cell device application. Cu₂ZnSnS₄ (CZTS) thin film was deposited by using simple chemical spray pyrolysis technique for substrate temperature (270±5) ^◦C. Analytical reagent Grade 0.025 M Copper chloride (CuCl₂), 0.0125 M zinc chloride (ZnCl₂), 0.0125 M Tin chloride (SnCl₄.5H₂O) and 0.05 M Thiourea (SC (NH₂)₂) were used as sources of copper (cu⁺ ), zinc (Zn⁺), tin (Sn⁺ ) and sulfur (S^- ) ions respectively. The structure, morphology and optical band gap of the film were investigated by using X-ray Diffractometer (XRD), Scanning Electron Micrograph (SEM) and UV-Visible spectroscopy respectively. Energy dispersive X-ray Analysis (EDX) was used for elemental analysis of deposited CZTS film. The XRD spectra showed that CZTS film exhibit polycrystalline tetragonal crystal structure with preferential orientation along (112) plane. The crystallite size calculated using full width at half maximum (FWHM) of (112) peak was to be 36.82 nm. SEM image revealed that film composed of regular arrangement of spherical granules of average size 1.61 µm. The purity of the CZTS phase was confirmed by elemental analysis. The calculated energy band gap (Eg) by using Tauc's plot was about 1.62 eV. The dc resistvity estimated by using IV characteristics of the CZTS film was to be 2.3× 10^-2 Ω-cm. It is concluded that CZTS film prepared using present deposition technique can be used for solar cell device applications. 

6 illus, 2 tables, 21 ref

042824   KUMAR R, KUMAR G, KUMAR M , GULERIA R P (Physics Dep, Govt. Coll Sarkaghat, Himachal Pradesh - 175024, Email: goldy_physics@rediffmail.com) : Spectral and seasonal variations of aerosol optical depth with special reference to Kanpur, Indo-gangetic Basin. Indian J Sci Technol 2020, 13(21), 2119–37.

To find characteristics of Aerosol optical depth (AOD) at ultraviolet (340-380 nm), visible (440-675 nm) and near-infrared (870-1020 nm) wavelength spectrum. During estimation of the radiative effect of aerosol in the atmosphere of earth radiation budget, it is important to study AOD. It is the total disappearance of sun rays due to aerosols in atmospheric column by absorption and scattering. AOD is being measured using ground based sensor called CIMEL Sun photometer over Kanpur as it is situated in the Indo-Gangetic Basin. The seasonal variations in AOD as well as in various months of the year at 340nm, 500nm and 1020nm under all clear days have been studied. The observations showed that AOD was increasing from Pre-monsoon to Post-monsoon season at short wavelengths; whereas it was found to be decreasing at longer wavelengths regions. Area under study is surrounded by small to large scale industries. Therefore, industrial emission is a major source of anthropogenic aerosols. The study of spectral and seasonal variations of Aerosol Optical Depth is important because the accumulation of aerosol particularly mixing state of aerosols has impact on atmospheric dynamics. Furthermore this work will also motivate the researchers to develop aerosol climatology map particularly for Indian regions. 

10 illus, 1 table, 47 ref

044802   SINHA N, SINHA P (Physics Dep, S.D. Coll, Muzaffarnagar, Email: piyushs03@gmail.com) : Cluster shell model wave function: Structure of ⁶li nucleus. J Mountain Res 2020, 15, 131-33.

In this paper cluster model wave function for 6Li using Shell Model with definite parity and angular momentum is written along with cluster co-ordinates, which are relative to the center-of-mass of various clusters and involve with parameters. These parameters can be adjusted to some extent to obtain predictions close to experimental properties. The cluster model wave function is written along with resonating group method (RGM) and the Complex Generator Coordinate Technique (CGCT). The Complex Generator Coordinate Technique allows the transformation of the cluster model wave function written in terms of cluster co-ordinates into anti-symmetrized product of single particle wave function. This wave function is written in terms of single particle co-ordinates, the center-of-mass co-ordinates, parameter coordinates and generator coordinates.

10 ref

044787   RAO V V, RAVINDRA V (IIT Kharagpur, Kharagpur, Email: vvrao@cryo.iitkgp.ac.in) : Vacuum furnaces for metallurgical processing. J Met Mater Sci 2020, 62(1-2), 123-9.

Large scale vacuum furnaces are becoming crucial in metallurgical processes like melting, casting, heat treatment, degassing, annealing and brazing. The vacuum conditions help in reducing contamination (like oxidation) and improve the micro-structure to get favourable metallurgical properties for industrial applications. The vacuum also reduces the melting and boiling points of metals and alloys, thereby reducing the electrical power requirement in high temperature furnaces for clean metallurgical processing. The present paper describes the design criteria of vacuum metallurgical furnaces involving vacuum equipment, heating elements and process instrumentation.

1 illus, 3 ref

042798   THIRUMAGAL N, JEYAKUMARI A P (Physics Dep, Thiruvalluvar Government Arts Coll, Rasipuram, Tamil Nadu, Email: pricilla1510@gmail.com) : Photocatalytic and antibacterial activity of silver nanoparticles (AgNPs) using palm (Borassus flabellifer L.) water ( Pathaneer ). Indian J Sci Technol 2020, 13(18), 1856–66.

To evaluate the photocatalytic and antibacterial activity of a biologically synthesized AgNPs mediated by palm (Borassus flabellifer) water against human pathogens. It is a potential candidate for preparing nanomedicine for constipation. 1mM of AgNO₃ is prepared and mixed with an appropriate volume of Pathaneer and the reaction was made up to 100ml. The AgNPs were characterized by X-ray diffraction, FT-IR, UV-Vis analysis and HRTEM. The photocatalytic property and the antibacterial activity were carried out for the prepared AgNPs. The powder X-ray diffraction investigation reveals the FCC structure of AgNPs with a crystalline size of 27nm and a lattice strain of 0.4283. FT-IR confirms the presence of Ag⁺ from UV-Vis, the energy band gap was found to be 2.92 eV. HRTEM was used to calculate the diameter of AgNPs as 5-10nm. In Borassus flabellifer, the percentage degradation state of AgNPs was estimated as 87 % at 180 minutes. AgNPs derived from Pathaneer have a large impact as antibacterial in the biomedical field. Since the aggressive chemicals are not involved in the preparation of AgNPs, it is used as an alternated biomedicine to reduce the toxicity of AgNPs and the photo degradation efficiency is high hence suitable for solar cells as well.

11 illus, 2 tables, 26 ref

042797   NAIDU T M , NARAYANA P V L (Nuclear Physics Dep, Andhra Univ, Visakhapatnam - 530 003, A.P, Email: pvl.nuclearphysics@gmail.com) : Synthesis and characterization of Fe₂O₃-Bi₂O₃-TiO₂nanoparticles and its magnetic properties. Indian J Sci Technol 2020, 13(18), 1848–55.

The current research work was investigated magnetic properties of Fe₂O₃-Bi₂O₃-TiO₂ nanoparticles (NP_S). The Fe₂O₃-Bi₂O₃-TiO₂ has been synthesized by a simple precipitation method. The samples were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier-Transform Infrared Spectroscopy (FTIR) and UV-vis. absorption (reflectance) spectra. The magnetic properties of the magnetite nanoparticles were calculated by vibrating sample magnetometer (VSM) at ambient temperature. The effect of calcination on the magnetic and structural properties of Fe₂O₃-Bi₂O₃-TiO₂ nanoparticles was studied. The Fe₂O₃-Bi₂O₃- TiO₂ nanocrystal was subjected to calcination up to 200 ^◦C, magnetite was converted to magnetite; the second transition was in the range of 300-400 ^◦C which changed it to hard ferromagnetic hematite. This research provides promising results concerned with magnetic sensing probes for magnetic resonance imaging for in-vitro diagnostics and contrast agents.

7 illus, 1 table, 16 ref

042779   AL-DMOUR H (Physics Dep, Mu'tah Univ, Mu'tah, 61710, Jordan, Email: hmoud79@mutah.edu.jo) : Admittance spectroscopy analysis of dye-sensitised solar cells with host-guest complexes. Indian J Sci Technol 2020, 13(16), 1686–92.

The objective of this study was to assess the influence of encapsulation of cis-bis(isothiocyanato)(2,2'-bipyridyl-4,4'-dicarboxylato)(4,4'-di-nonyl-2'- bipyridyl) ruthenium(II) (Z907 dye) to macrocycle cucurbit[7]uril (CB7) (host) on the performance of nanocrystalline titanium dioxide (nc-TiO₂)/ poly3-hexylthiophene (P3HT) heterojunction solar cell. Two solar cells composed of five layers with and without the encapsulation of Z907 dye on the top of TiO₂ film were used. The admittance spectroscopy was measured at different frequencies to confirm the modification of the interfacial layers' properties in solar cells. The results demonstrated different capacitance responses depending on the voltage applied to the devices. The encapsulated device had a higher capacitance response to forward bias and reverse bias than the non-encapsulated device at the same frequency. The negative capacitance of the two devices was also observed. The results were attributed to an increase in the accumulation of charge carriers and the formation of electric dipoles at the junction which rapidly decreased the capacitance to negative values.This study demonstrated that using encapsulation of dye improved the solar cells' maximum electric power to 0.14mW/cm² , while it was 0.04 mW/cm² in the non-encapsulated solar cells.

10 illus, 21 ref

042774   AROHAN R, SHARMA R K (Aerospace Engineering Dep, Karunya Institute of Technology and Sciences, Coimbatore - 641 114, Tamil Nadu, Email: ritesharohan8@gmail.com) : Periodic orbits in the planar restricted photo-gravitational problem when the smaller primary is an oblate spheroid. Indian J Sci Technol 2020, 13(16), 1630–40.

This study deals wit h the stationary solutions of the planar circular restricted three-body problem when the more massive primary is a source of radiation and the smaller primary is an oblate spheroid with its equatorial plane coincident with the plane of motion. The objective is to study the location of the Lagrangian points and to find the values of critical mass. Also, to study the periodic orbits around the Lagrangian points. A new mean motion expression by including the secular perturbation due to oblateness utilized by(^1,2) is used in the present studies. The characteristic roots are obtained by linearizing the equation of the motion around the Lagrangian points. The critical mass parameter µcrit(^3,4) , which decreases radiation force, whereas it increases with oblateness when we consider the value of new mean motion. Through special choice of initial conditions, retrograde elliptical periodic orbits exist for the case µ = µcrit, whose eccentricity increases with oblateness and decreases with radiation force for non-zero oblateness, although there is slight variation in L₂ location.

7 illus, 7 tables, 14 ref

042768   SINGH V K, SRIVASTAVA S , VIBHU I (Physics Dep, Integral Univ, Lucknow - 226 026, U.P, Email: singh87vishal@gmail.com) : Study of transmittance spectra for quaternary periodic structure of 1D photonic crystal for s-wave filter. Indian J Sci Technol 2020, 13(15), 1580–8.

To study the propagation of electromagnetic waves through the four periodic continuous layers with different refractive indices and spectral analysis with normalized frequency with respect to transmittance and dispersion. By considering the assumptions the theoretical analysis has been done. Methodology has taken from quantum mechanical treatment of an electron in a potential well with boundary conditions. The dispersion relation is taken from Bloach wave concept. The calculation is taken for arbitrary structure of different refractive indices. The electric field has connected with the periodic 1-D layered structure. The electromagnetic wave as form incident wave, the transmitted wave and reflected wave have been derived using the transmission matrix method. In theoretical analysis, it is found that the transmittance spectra increasing with continuous increase refractive index. The analysis has been done for a s-polarized or transverse electric mode (TE mode) wave. Properties of these crystals are different from the ordinary materials. It works as s- polarized filter and blocks p-polarized wave. Calculation has taken for TE mode configuration.

16 illus, 15 ref

044761   NOORI-ASL M (Physics Dep, Mohaghegh Ardabili Univ, Ardabil, Iran, Email: nooriasl.mahsa@gmail.com) : Investigation of different factors affecting the quality of spect images: A simulation study. J Med Phys 2020, 45(1), 44-51.

Monte Carlo (MC) simulation codes are used extensively for modeling the nuclear medicine imaging systems, such as single photon emission computed tomography (SPECT) and positron emission tomography (PET). By using these codes, it is possible to set different imaging parameters and do various studies in the field of nuclear medicine imaging.  The aim of this study is to investigate the effective factors in improvement of the SPECT image quality by using MC simulation. Materials and Methods: In this study, we used the SIMIND MC simulation code and Jaszczak phantom containing six spheres with different diameters placed into a waterfilled cylindrical phantom for consideration of the effects of different factors on quality of the images obtained from Tc-99m SPECT imaging system. The assessment criteria used to investigate these factors included image contrast, signal-to-noise ratio (SNR) and relative noise of the background (RNB). The results of this study show that the right choice of the arc of rotation, the image matrix size, the number of angular views, type of the collimators, and also filters used in the image reconstruction affect the quality of SPECT images. Also, we show that use of scatter correction methods can improve the image quality. The MC simulation is a suitable tool for investigation of different factors affecting the quality of SPECT images, essentially in the studies based on the energy spectrum, such as the evaluation of the scatter correction methods.

15 illus, 3 tables, 26 ref

042757   NIGAM J, KUMAR P , SINGH P P , SILAMBARASAN N S , NAVITHA S (Physics Dep, Invertis Univ, Bareilly, Email: jnbarc37@yahoo.com) : Evaluation and validation of the machine performance check application for trueBeam 2.5 linac. Indian J Sci Technol 2020, 13(14), 1470–5.

To evaluate the Machine Performance Check (MPC) 1.1 application for TrueBeam 2.5 and to establish MPC application as a comprehensive daily QA tool after verification. An automated daily Quality check application MPC using IsoCal Phantom provided by Varian Medical System (VMS) to perform the essential tests such as beam consistency that is dosimetric performance and mechanical check were performed on TrueBeam. The data was collected over a period of four months (84 days). MPC acquired data consists of a series of generation of images using MV and kV at various gantry, collimator, and couch positions. The collected data is analyzed for daily reproducibility as well as comparison with ion chamber measurements. The results showed that the reproducibility of MPC was less than the tolerance values for the respective mechanical parameters. The MPC measured isocenter with mean value of 0.35 mm is within tolerance. The Beam Consistency showed that over a period of four months, the mean value of output measurement of 6 MV photon beam as measured by the MPC and Farmer Type Chamber FC65-G differ by less than 1 %. It is evident that the MPC proved to be fast and easy to use QA tool for daily checking of machine performance. But it is evident from present study that, inter comparison with a Farmer Type chamber is needed, if the MPC has to replace the other QA tools.

11 ref

044760   GALIC S, KOVACEVIC M, LASIC I, BRKIC H, FAJ D (Clinical Hospital Mostar Univ, Mostar- 88000, Bosnia and Herzegovina, Email: medicinskafizika@skbm.ba) : A method of high resolution radiotherapy delivery fluences with a pair of fields with orthogonal collimator settings: A study on ten head and neck cancer patients. J Med Phys 2020, 45(1), 36-43.

Introduction of dual‑layer multileaf collimator (MLC) radiotherapy linear accelerators into clinical practice is an important development in advanced external beam radiotherapy. A method of delivering comparable high‑resolution fluences with a single‑layer MLC is presented. The aims of this study are to present new algorithms and approaches to define high‑resolution hypermodulated fluences, obtain orthogonal decomposition of fluences, and deliver them on a linear accelerator with single MLC from two perpendicular collimator settings. High‑resolution fluences were defined using Monte Carlo (MC) calculation. Anovel use of a limited‑memory, bounded, Broyden–Fletcher–Goldfarb–Shanno algorithm was used to decompose such fluences to ones deliverable with a pair of fields with mutually orthogonal collimator settings. Such a technique, here named cross motion leaf calculator(XMLC), is compared against single sliding window (SSW) technique typically used in intensity‑modulated radiation therapy (IMRT). An electronic portal imaging device (EPID) is used, and the results were compared with gamma analysis. Furthermore, MC was used to determine dose distributions for computed tomography images of ten head‑and‑neck cancer patients. Gamma analysis (3 %, 3 mm) against ideal fluence is considerably more favorable to XMLC (94 % ± 4 %) versus SSW (76 % ± 5 %). Furthermore, the dose–volume histogram (DVH) analysis showed that XMLC enables delivery of fluences superior to that of IMRT and these results in clinically relevant enhancements in DVH results.  At the time of writing of this study, there were more than 12,000 medical linear accelerators in clinical use, and XMLC can prove itself useful wherever linac is equipped with MLC but cannot delivery latest techniques, such as volumetric modulated arc therapy

4 illus, 4 tables, 31 ref

044759   SARIN B, BINDHU B, SAJU B, NAIR R K ( Physics Dep, Noorul Islam Centre For Higher Education, Thiruvananthapuram? 695 011, Kerala, Email: sreesarin@gmail.com) : Validation of primo monte carlo model of clinac®ix 6mv photon beam. J Med Phys 2020, 45(1), 24-35.

This study aims to model 6MV photon of Clinac^®iX linear accelerator using PRIMO Monte Carlo (MC) code and to assess PRIMO as an independent MC‑based dose verification and quality assurance tool. Materials and Methods: The modeling of Clinac^®iX linear accelerator has been carried out by using PRIMO simulation software (Version 0.3.1.1681). The simulated beam parameters were compared against the measured beam data of the Clinac^®iX machine. The PRIMO simulation model of Clinac^®iX was also validated against Eclipse^® Acuros XB dose calculations in the case of both homogenous and inhomogeneous mediums. The gamma analysis method with the acceptance criteria of  2 %, 2 mm was used for the comparison of dose distributions. Gamma analysis shows a minimum pass percentage of 99 % for depth dose curves and 95.4 % for beam profiles. The beam quality index and output factors and absolute point dose show good agreement with measurements. The validation of PRIMO dose calculations, in both homogeneous and inhomogeneous medium, against Acuros^® XB shows a minimum gamma analysis pass rate of 99 %. This study shows that the research software PRIMO can be used as a treatment planning system‑independent quality assurance and dose verification tool in daily clinical practice. Further validation will be performed with different energies, complex multileaf collimators fields, and with dynamic treatment fields.

11 illus, 10 tables, 32 ref

044757   DONA K N U G, SHANG C, LEVENTOURI T (Physics Dep, Florida Atlantic Univ, Florida, USA, Email: gudeni2014@fau.edu) : Dosimetric comparison of treatment plans computed with finite size pencil beam and monte carlo algorithms using the incise™ multileaf collimator equipped cyberknife® system. J Med Phys 2020, 45(1), 7-15.

InCise™ multileaf collimator (MLC) was introduced for CyberKnife® (CK) Robotic Radiosurgery System (CK‑MLC) in 2015, and finite size pencil beam (FSPB) was the only available dose computation algorithm for treatment plans of CK‑MLC system. The more advanced Monte Carlo (MC) dose calculation algorithm of lnCise™ was initially released in 2017 for the CK Precision™ treatment planning system (TPS) (v1.1) with new graphic processing unit (GPU) platform. GPU based TPS of the CK offers more accurate, faster treatment planning time and intuitive user interface with smart three‑dimensional editing tools and fully automated autosegmentation tools. The MC algorithm used in CK TPS simulates the energy deposited by each individual photon and secondary particles to calculate more accurate dose. In the present study, the dose disparities between MC and FSPB algorithms for selected Stereotactic Ablative Radiation Therapy (SABR) CK‑MLC treatment plans are quantified.  A total of 80 CK‑MLC SABR plans computed with FSPB were retrospectively reviewed and compared with MC computed results, including plans for detached lung cancer (or tumors fully surrounded by lung tissues, n = 21), nondetached lung cancer (or tumor touched the chest wall or mediastinum, n = 23), intracranial (n = 21), and pancreas lesions (n = 15). Dosimetric parameters of each planning target volume and major organs at risk (OAR) are compared in terms of normalized percentage deviations (Ndev). This study revealed an average of 24.4 % overestimated D95 values in plans using FSPB over MC for detached lung (n = 21) and 14.9 % for nondetached lung (n = 23) lesions. No significant dose differences are found in intracranial (0.3 %, n = 21) and pancreatic (0.9 %, n = 15) cases. Furthermore, no significant differences were found in Ndev of OARs. In this study, it was found that FSPB overestimates dose to inhomogeneous treatment sites. This indicates, the employment of MC algorithm in CK‑MLC‑based lung SABR treatment plans is strongly suggested.

7 illus, 2 tables, 37 ref

042719   MUTHUKRISHNAVENI M (Physics Dep, Sri Ramakrishna Institute of Technology, Perur Chettipalayam, Tamilnadu, Email: mmkrishna. veni83@gmail.com ) : Polaizability and susceptibility in the valley orbit split states in an intense field. Indian J Sci Technol 2020, 13(10), 1107 – 15.

To compute the polarizability and diamagnetic susceptibility values of a shallow donor in the valley – orbit split A₁, T₂, and E states of a many valley semiconductor. We demonstrate the enhanced values of the above quantities in the excited states, which clearly indicate a catastrophic behavior when Metal-Insulator Transition is approached. In intense magnetic fields, the polarizability values decrease as the system behaves like a harmonic oscillator. In an electric field, the magnitude of the diamagnetic susceptibility values increases.

4 illus, 2 tables, 34 ref

042704   SISODIA A K, MATHUR R K (Physics Dep, Affiliated to Maharshi Dayanand Saraswati Univ, Ajmer, Rajasthan, Email: anilsisiitd@ yahoo.co.in) : Performance analysis of photovoltaic module by dust deposition in Western Rajasthan. Indian J Sci Technol 2020, 13(8), 921 – 33.

Dust soiling is a main contributing environmental issue with the climatic condition of Western Rajasthan that influences adversely the performance of solar PV technology. The deposition of dust particles reduces the solar output by hampering the solar radiation. To explore the trend of dust soiling rate over different seasons in a year and its impact on the performance of solar photovoltaic (PV) system in Western Rajasthan in India. Especially, dust particle settlement is primarily affecting the optical properties of the PV modules, which results in declining their output electrical energy yield. Thus, it adds significantly to quantify the effect of soiling by measuring transmittance losses and soiling ratio with different dust particles. This article presents a significant loss in output energy yield of photovoltaic system with the layer by layer deposition of the different dust particles in Western Rajasthan. In the context of physical properties, the XRD and SEMEDS analysis of the collected dust sample from SOTA is carried out, and also the dust particle size study has been performed in order to observe the sediment characteristics of various dust samples in Western Rajasthan. The preliminary results depict the optical (glass transmittance) and electrical (soiling ratio) parameters strongly depend on the dust properties and its deposition density. With this consideration, the highest power loss is observed in the Bikaner dust sample (S1) due to its high transmittance loss (96.1 %) and whiles the minimum for Barmer (78.4 %). This study can be useful to guide the appropriate level of dust soiling mitigation on solar PV systems in an arid or particular region. It can also be decided on the optimal cleaning schedule in actual conditions in the year.

12 illus, 1 table, 38 ref

042693   MOHAMMED H J, SALIH A-K M (Physics Dep, Thi-qar Univ, Iraq, Email: abdulkareem@utq.edu.iq ) : Simulation of the effect of the detuning in the performance of the two-level system. Indian J Sci Technol 2020, 13(7), 787 – 98.

To study the effect of resonance and non-resonance wave–matter interaction on the behavior of dispersion, absorption, and population inversion as a component of nonlinear polarization by simulation to describe the temporal variation of two-level system. Software program was prepared in the study to solve normalized optical Bloch equation model numerically by Rung-Kutta–Fehelberg method. The study showed that the dispersion not occurs at resonance state, while occurs at detuning state, it decreases with the increasing of detuning, so the decreasing of absorption, population inversion was observed with the increasing of detuning. While the value of saturation parameter increases with the increasing of detuning value. The appropriate intensity (saturation intensity I_sut.) to reach the steady state of population inversion as a function of initial (incident I_int.) intensity on the system has been estimated.

5 illus, 20 ref

040873   TRIPATHY N K, PRAVEEN M G, RAGHUNANDAN V, MUKHERJEE M, DAHIYA M (Institute of Aerospace Medicine IAF, Bengaluru - 560 017, Karnataka, Email: nktdoc@yahoo.com) : Establishment of a normative data for cervical and lumbar spine movements using spinal column analysis system. Indian J Aerosp Med 2020, 64(2), 51-5.

The current assessment of spine movements during aeromedical evaluation of aircrew is performed using the CMS 20 spinal column analysis system. However, in the present configuration, the normal ranges of cervical and lumbar spine motions depicted by the equipment are based on normative data of German population measured by goniometric method. The study was conducted to generate normative values of cervical and lumbar spine movements with respect to age-specific Indian male population. The study included a total of 225 healthy male Indian volunteers, divided into three age groups; <25 years, 25–35 years, and above 35 years, with 75 subjects in each age group. In each participant, ten cervical spine movements and six lumbar spine movements were recorded using CMS 20 S spinal column analysis system. The data were statistically analyzed to establish normative data for each of the cervical and lumbar spine movements for three age groups (<25 years, 25–35 years, and >35 years). The mean age, height & weight of the participants were 21.2, 28.3 and 39.4 years, 173.1, 171.6 and 170.6  cm, 65.9, 68.7 and 70.2 kg respectively for the three different age groups - <25 years, 25-35 years and >35 years. The mean values along with standard deviation of the ten cervical and eight lumbar spine movements were derived and presented for the three different age groups. The normative data generated in the present study as per the three age groups may be used as reference values for male Indian personnel for that specific age groups for the assessment of cervical and lumbar spine movements using spinal column analysis system. The data may also be used as baseline data for aeromedical evaluation and future aviation research involving the same equipment.

1 illus, 5 tables, 21 ref

040867   KASTURE S, SHARMA M, NATARAJA M (Institute of Aerospace Medicine IAF, Bengaluru - 560017, Karnataka, Email: shivani.kasture30@gmail.com) : Correlation of age, height, and gender with +Gz tolerance among healthy Indian participants. Indian J Aerosp Med 2020, 64(1), 14-7.

Aircrew are repetitively exposed to positive Gz acceleration in fighter flying. Factors affecting +Gz tolerance vary among individuals and are determined by both modifiable and non-modifiable factors. Some of the non-modifiable factors influencing +Gz tolerance are age, gender, and height. The present study was undertaken to understand the relationship of these variables with relaxed +Gz tolerance. The study involved a retrospective analysis of existing database of the high-performance human centrifuge at the Institute of Aerospace Medicine. Relevant data from 70 non-aircrew subjects were included for the study. Of these, 39 were male and 31 were female. The age and height varied from 27 to 38 years and 157 to 187  cm, respectively. The data were analyzed using Microsoft Office Excel^® to find the correlation between age and height with relaxed +Gz tolerance. Relaxed +Gz tolerance of men and women was compared using unpaired t-test. Significance was set at P < 0.05. The mean age, height, and relaxed +Gz tolerance of males were found to be 30.25 ± 4.3 years, 172.58 ± 6.5 cm, and 4.89 ± 0.67G, respectively, whereas those of females were 27.28 ± 3.36 years, 158.46 ± 6.78 cm, and 4.4 ± 0.85G, respectively. In both males and females, age and height showed no correlation with relaxed +Gz tolerance. However, the relaxed +Gz tolerance was found to be higher in males and this difference was statistically different (P = 0.008). Age and height showed no correlation with relaxed +Gz tolerance in both males and females nonaircrew subjects. Males exhibited a statistically significant, higher relaxed +Gz tolerance as compared to females.

2 illus, 2 tables, 19 ref

040866   HARSHITH H, BHATTACHARYA U, NATARAJA M, AGARWAL A (Institute of Aerospace Medicine IAF, Bengaluru - 560 017, Karnataka, Email: harshith.hs@gmail.com) : Coriolis time Intervals in prediction of outcome of motion sickness desensitization therapy. Indian J Aerosp Med 2020, 64(1), 8-13.

Motion sickness is a common problem faced during flying training. Aircrew with persistent motion sickness require motion sickness desensitization. Although many aircrew benefit from the motion sickness desensitization therapy (MSDT), a significant number of individuals fail to complete the desensitization program. Early prediction of desensitization program outcome would identify non-responders and help in increasing the efficiency of MSDT. A retrospective survey of candidates who underwent MSDT at the Institute of Aerospace Medicine between 2009 and 2019 was done. Coriolis time interval (CTI) values of 28 candidates could be retrieved. Mean CTI values of the successful and unsuccessful candidates at 5 rotations per minute (RPM) were compared. Statistical analysis was done using independent t-test, binary logistic regression, and a receiver operator characteristics (ROC) analysis. The unsuccessful group candidates (M = 14.3, SD = 8.7 s) had significantly higher mean CTI values at 5 RPM than the successful group candidates (M = 6, SD =2.3 s); t (15.09) = −3.43, P = 0.04. Logistic regression indicated that there was a significant association between the CTI values and MSDT outcome, Chi-square (1, n = 26) =12.73, P ≤ 0.001. ROC analysis revealed a statistically significant curve with a good predictive cutoff value for CTI to identify non-responders. Results indicated that CTI values are reliable indicators in predicting the outcome of MSDT. Inclusion of other parameters, both physiological and psychological, that have a good correlation with motion sickness may give us better predictive models. Such predictors will also help in better understanding of the pathophysiology of motion sickness and in formulating improved treatment modalities.

4 illus, 23 ref

042561   SINGH T, RANI P , SINGH P K, GAHLAUT V (Physics Dep, Banasthali Univ, Rajasthan - 304 022, Email: vgceeri@gmail.com) : A low voltage actuated RF-MEMS shunt capacitive switch. Indian J Radio Space Phys 2020, 49(1-2), 48-52.

Micro electromechanical system switches (MEMS) have procured remarkable attention in recent years due to their perceptible accomplishment in RF and microwave areas. The major challenge in RF-MEMS is to minimize the actuation voltage deprived of restoring force losses. The proposed design presents the analysis of a low actuation voltage shunt capacitive RF-MEMS switch. The proposed switch comprises low actuation voltage, low insertion loss and very high isolation. A horizontal structure of bridge membrane is exhibited in this design and its vertical movement is presided by the electrostatics MEMS actuation technique, which actually provides the ON and OFF conditions of the switch. The actuation pad is fed by coplanar wave guide (CPW) transmission line. The switch performance is successfully evaluated for a large frequency range from 1 GHz to 40GHz. The actuation voltage of the proposed design has been observed to be 3.0 Volts for a vertical displacement of 1.5 μm. Moreover, the fixed-fixed flexures beam structure offers the isolation of -43 dB and insertion loss of -0.12 dB at 28 GHz.

8 illus, 5 tables, 11 ref

042560   DEBNATH A (North Eastern Space Applications Centre, Umiam - 793103, Meghalaya, Email: anjan.debnath@nesac.gov.in) : Ka-Band signal propagation experiment at NESAC Umiam. Indian J Radio Space Phys 2020, 49(1-2), 42-7.

A Ka-Band signal propagation study under tropical monsoon climate has been taken up jointly by ISRO/ONERA/CNES. The program has been aimed at finding the degree to which Ka-Band satellite signals get affected by rain. Dual polarized Ka Band beacon signals onboard GSAT-14 satellite, of frequencies 20.2 GHz and 30.5 GHz, have been used for the experiment. Data available by various instruments has been compared with ITU-R predicted values. Results for the years 2016 and 2017 at Umiam has shown underestimation of both Rainfall and Signal Attenuation by ITU-R predicted models. It has also been found that the Rainfall has been mostly concentrated in three months (June, July, August) and the maximum attenuation that Ka-Band signals have suffered during rain at Umiam has been around 30-40 dB. The actual Rainfall and Attenuation of both 20.2 GHz and 30.5 GHz signals have been compared with ITU-R predictions and has been found to be much above the predicted levels. A Study of the Z-R relationship for the rainfall and comparison with known relations has indicated that a new distribution is required for the region.

3 illus, 8 tables, 11 ref

042559   SRIVASATAVA A (Geoinformatics Dep, Indian Institute of Remote Sensing, Dehradun - 248 001, Email: asrivastava@iirs.gov.in) : A study on position estimation algorithm using global positioning system satellites data. Indian J Radio Space Phys 2020, 49(1-2), 33-41.

An investigation is carried, to study the position estimation algorithm by a receiver using GPS satellites. The RINEX version 2.11 data were used for the analysis as input to test and establish an algorithm. The obtained position from the mathematical algorithm was compared with the reference position. Dilution of Precision (DOP) estimation is also carried out to analyse the geometry of global positioning system (GPS) satellites as observed by the receiver and its effect on position estimation. It is observed that, using a position estimation algorithm that is developed for this study, a good estimate of location is obtained and is found matching with the reference values closely and exhibited better estimates if compared with portable GPS receiver measurements. The results obtained after processing RINEX data shows the difference close up to 6th decimal places or up to centimeter-level for latitude and longitude.

11 illus, 7 tables, 17 ref

042558   DEBNATH A (Space Dep, North Eastern Space Applications Centre, Meghalaya - 793 103, Email: anjan.debnath@nesac.gov.in) : Analysis of anomalous ionospheric total electron content variation for earthquakes in South East Asian region with IGS network. Indian J Radio Space Phys 2020, 49(1-2), 28-32.

A study to find ionospheric Total Electron Content (TEC) anomaly around various earthquake days that occurred during January, 2016 to March, 2017 in the South East Asian region has been undertaken. Large magnitude shallow earthquakes have only been considered. In the study, VTEC data from IGS network has been analyzed with the help of IONOLABTEC software tool. The analysis has been done based on IGS stations that fall within Dobrovolsky Radius of each earthquake. The analysis has included geo magnetically quiet days only to take out all non-seismic effects in the ionosphere. The analysis has shown TEC irregularity few days around almost all earthquake events.

2 illus, 4 tables, 20 ref

042557   KUMAR A (Physics Dep, Amity Univ, Noida - 201 303, Uttar Pradesh, Email: adarsh_phy@yahoo.co.in) : Long term (1975-2016) anomaly of surface latent heat flux (SLHF) over Indian subcontinent: Signatures of early warning of earthquake disasters. Indian J Radio Space Phys 2020, 49(1-2), 19-27.

A long-term anomaly study of 42 years (1975-2016) of surface heat flux (SLHF) from the epicentres of the earthquakes over the Indian subcontinent carried out. The results of study revealed anomalous behaviour. On an average, maximum surge of SLHF was found to be 10-15 days before the main earthquake events which were likely due to the ocean atmosphere interaction. This improvement of SLHF before the most earthquake events was considerably attributed to the surge in infrared thermal (IR) temperatures within the epicentral and near surroundings. The abnormal surge in SLHF provides associate early cautionary of a ruinous earthquake during a region, provided there's a decent understanding of the ground noise because of the zonal tides and regional monsoon in surface heat energy flux. A lot of effort has been put to have an understanding of the level of background noise within the epicentral regions of the 10 earthquakes over the Indian Subcontinent during the last 42 years. Latitudinal and longitudinal effects of SLHF anomaly for the ten earthquakes over Indian Subcontinent were studied, which showed that the anomalous behaviour of SLHF before the main earthquake events were somewhat associated only with the coastal earthquake activities.

6 illus, 1 table, 39 ref

042556   BHAWRE P, YADAV R (Rani Durgawati P.G. Coll, Madhya Pradesh - 481 661, Email: bhawre@gmail.com) : Characteristic of sporadic-E over the anomaly crest region during the low solar cycle. Indian J Radio Space Phys 2020, 49(1-2), 13-8.

The paper describes the occurrence of the sporadic-E layer for the anomaly crest region Bhopal,   (23.2 ° N, 77.4 ° E and 18.4 °) over four years, covering the waning phase of the 23^rd Solar Cycle and the preliminary phase of 24^th Solar Cycle. This precise period is very appropriate for observing the sunspot number and it includes periods of stumpy solar activities. We also included space weather activities along with it. We have taken the auroral electrojet index (AE) and, disturbed storm time index (Dst), Interplanetary Magnetic Field (Bz), to characterize the storm intensity. The sunspot number (Rz), solar flux (F10.7) and Proton Density are described in solar activities. The occurrence probability of Sporadic- E, the layer is maximum in the summertime, temperate during the equinox time, and low during the wintertime. Noteworthy occurrence summits appears from June to July in summer and from December to January in winter. The layer occurrence exhibited a dual peak variation with individual layer group, in the morning and the other during the evening. The dawn layer ancestry was related to layering density-increased representative the consolidation of the layer while it decreased during the evening layer ancestry.

4 illus, 21 ref

042555   GHOSH A, HAZRA P , DE S S , GUHA G, BISWAS D (Calcutta Univ, Kolkata - 700 009, Email: abhijit3034@gmail.com) : Responses of meteorological parameters during August 24, 2016 Myanmar earthquake. Indian J Radio Space Phys 2020, 49(1-2), 5-12.

A continental plate movement in the Sunda Trench region resulted into the Myanmar Earthquake (M=6.8) of 24 August, 2016. The variations in the lithosphere–atmosphere-ionosphere (LAI) coupling take place during the occurrence of the earthquake. The thermodynamic equilibrium of the troposphere is very much connected with the atmospheric pressure, temperature, humidity, rainfall and wind speed. Some anomalies are observed on the surface temperature and other atmospheric parameters during the period. The anomalous surface latent heat increase takes place within a time interval of several days before a strong earthquake in this earthquake preparation zone. The variations in Lithosphere-Atmosphere-Ionosphere coupling during Myanmar earthquake (M=6.8) resulted in anomalous changes in different meteorological parameters. The variations in LAI may be due to enhanced radon and other greenhouse fluid emanations during the pre and post earthquake period. The meteorological data analyzed to investigate these observations as well as to invoke responses of the Myanmar earthquake. The occurrences of precursors during the pre-and post-periods of this earthquake from 1 August, 2016 to 30 August, 2016 are reported.

2 illus, 27 ref

042553   BHARTI, KARAYEL A , GUPTA M , AHMAD G ,KUMAR Y, SHARMA S (Physics Dep, Delhi Univ, New Delhi- 110 021, Email: ykumar@arsd.du.ac.in) : Physical properties of heteroatom doped graphene monolayers in relation to supercapacitive performance. Indian J Pure Appl Phys 2020, 58(12), 885-91.

Electrodes fabricated using graphene are quite promising for electric double layer capacitors. However graphene has the limitations of low ‘Quantum Capacitance (QC)’ near fermi level due to the presence of Dirac point that can be modified by doping graphenewith suitable dopant. The density functional theory DFT calculations are performed for doped graphene using Boron, Sulphur and phosphorus as dopants to improve the quantum capacitance of electrodes fabricated using graphene. The calculations are performed at temperatures of 233, 300 and 353 °K. From present calculations no significant temperature dependence of quantum capacitance is observed, however a marked increase in QC of value above 58μFcm^-2 is seen. Forphosphorus and Sulphur doped graphene a significant energy gap shift of ~ 1.5 eV from the Fermi level is observed that significantly increases the QC at Fermi level to a high value of ~ 35 μFcm^-2. With boron dopant as well, a shift of energy gap ~ 1.25eV from the Fermi level is observed. The shift in Dirac point increases quantum capacitance at Fermi level that in turn can increase the energy density of supercapacitor remarkably. The effect of increasing doping concentration on quantum capacitance is also investigated. These results suggest that doping of graphene may result in significant increase in QC near Fermi level, if the dopants are selected carefully depending upon the use of graphene as a positive or negative electrode. The results of these calculations reveal that the problem of low QC of graphene in the range of interest can be addressed by modifying itssurface and structure chemistry which may increase energy density in supercapacitors.

8 illus, 25 ref

042551   KUMAR P S , SAKUNTHALA A, REDDY M V, RAOD R P , CHOWDARI B V R, ADAMS S (Physics Dep, Karunya Institute of Technology and Sciences, Coimbatore - 641 114, Tamil nadu, Email: meetsaku@gmail.com) : Electrochemical and lithium-ion transport properties of layered Li-rich Li_1.10(Ni_0.32X_0.01Co_0.33Mn_0.33) O₂ (X = Dy/Gd/Ho) positive electrodes. Indian J Pure Appl Phys 2020, 58(12), 864-76.

Layer structured Li_1.10(Ni_0.32X_0.01Co_0.33Mn_0.33)O₂ (X = Dy/Gd/Ho) compounds were synthesized via the microwave assisted solvothermal route. The impacts of doping on the electrical and electrochemical properties of  Li_1.10(Ni_0.32X_0.01Co_0.33Mn_0.33)O₂ compounds were investigated. Rietveld refined XRD pattern showed Li_1.10(Ni_0.32X_0.01Co_0.33Mn_0.33)O₂ compounds with layered hexagonal structure. SEM images revealed the compounds with micrometer sized grains. The Li_1.10(Ni_0.32X_0.01Co_0.33Mn_0.33)O₂ compound delivered an initial discharge capacity of 197 mAh/g at 0.2C and retained a capacity of 163mAh/g after 50^th cycle in the voltage window of 2.5-4.6V. The cycling stability of Li_1.10(Ni_0.32X_0.01Co_0.33Mn_0.33)O₂ compound was improved with rare earth doping. Li_1.10(Ni_0.32X_0.01Co_0.33Mn_0.33)O₂ compound delivered the discharge capacity of 166 mAh/g after50th cycle in the potential window 2.5-4.6V at 0.2C with 100 % capacity retention. AC impedance studies displayed the electrical conductivity in the order of 10^-6 S/cm. Wagner polarization analysis revealed the improvement in electronic transference number via rare earth doping.

8 illus, 3 tables, 40 ref

042550   OLIVEIRA J D, PIRES L F, CÁSSARO F, BRINATTI A M, SAAB S C (Physics Dep, State Univ of Ponta Grossa (UEPG), CEP 84.030-900, Ponta Grossa, PR, Brazil, Email: jossajato@gmail.com) : Modeling of soil water retention based on 3D micro-tomographic image analysis. Indian J Pure Appl Phys 2020, 58(12), 858-63.

This paper proposes the use of an algorithm based on the mercury intrusion porosimetry (MIP) method to obtain the water retention characteristic curve (pF curve) of a soil under different treatments. 3D X-ray micro-tomographic images were used to quantify pore size distribution, which was employed for the evaluation of the water retention in different matric potentials. The results showed very good agreement between the traditional method (obtained by suction tables) and that one based on the MIP algorithm. It means that the use of simulation procedures can be an interesting alternative for the measurement of soil water retention properties.

3 illus, 1 table, 33 ref

042548   KESHAV R , VALI I P, P K SHETTY P K , VAISHNAVI K S , RAJESHWARI M, MAHESH M G (Physics Dep, Manipal Institute of Technology, Karnataka - 576 104, Email: mahesha.mg@manipal.edu) : I – V characterization of vacuum deposited zinc selenide – silicon hetero junction. Indian J Pure Appl Phys 2020, 58(11), 841-6.

Zinc selenide (ZnSe) thin films were grown on silicon (Si) wafer by thermal evaporation and the hetero-structure was subjected to annealing at various temperatures. X-ray diffractogram recorded for various samples were analysed to extract the structural information including crystallite size, strain and dislocation density. ZnSe films exhibited cubic structure with (111) orientation and the crystallite size has increased from about 21 nm to 43 nm upon annealing at 673 K. Annealing at temperature above this has degraded the films. I – V characterization has shown nonlinear relation and affected by post deposition annealing. Thermionic emission and Cheung models were applied to obtain various parameters that assess the performance of hetero-structured devices. Minimum ideality factor was observed (n = 1.75 from Cheung Model) for as deposited system and it increased after annealing. Analysis has proven that series resistance increases after annealing under air ambience.

5 illus, 2 tables, 20 ref

042547   SHARMA H K, SHARMA S K, KUMAR S, SINGH B P (Physics Dep, Ch. Charan Singh Univ, Meerut-250 004, UP, Email: sksharma18@ccsuniversity.ac.in) : Effect of CNT on the growth and agglomeration of TiO₂ nanoparticles. Indian J Pure Appl Phys 2020, 58(11), 825-31.

Titanium dioxide nanoparticles (TiO₂-NPs) are agglomerated by inclusion of CNTs during the nucleation and growth process using the hydrothermal method at 160 ⁰C. The content of C-atoms was determined from EDAX-spectra and line scan. The XRD peak of TiO₂ indicated the rutile phase R(210), while CNT- TiO₂ showed the anatase phase A(004). Williamson-Hall (W-H) models showed the linear fitted negative slope, indicated the presence of compressive strain in TiO₂ and CNT- TiO₂ crystal lattice. Agglomeration of TiO₂ nanoparticles was confirmed from the surface morphology and elemental analysis. The FTIR spectra showed the interfacial interaction between CNTs and TiO₂ with vibrational frequency of Ti-O-C bonds at 1065 cm^-1.

7 illus, 2 tables, 39 ref

042546   GHERIBALLAH S, BOUABDELLAH B , OUGHILAS A , BOUKLI M A , RAHMOUNE M, SAYEDE A (Sidi Bel-Abbes Univ, Sidi Bel-Abbes 22000, Algeria, Email: gheriballahslimane@gmail.com) : Investigating structure, magneto-electronic, and thermoelectric properties of the new d0 quaternary Heusler compounds RbCaCZ (Z = P, As, Sb) from first principle calculations. Indian J Pure Appl Phys 2020, 58(11), 818-24.

The ab initio calculations based on the density functional theory (DFT) using the self-consistent full potential linearized augmented plane wave (FPLAPW) method were performed to explore the electronic structures, magnetic and thermoelectric properties of quaternary alloys RbCaCZ (Z = P, As, Sb) with quaternary Heusler structure. Results showed that FM-Y3 is the most favorable atomic arrangement. All the compounds are found to be half-metallic ferromagnetic materials with an integer magnetic moment of 2.00 μ_B, which predominantly derives from the strong spin polarization of p channels of C hybridized with Z elements. The predicted minority (half-metallic) band gaps were found to be 1.86 (0.87), 1.72 (0.78), and 1.78 (0.71) eV for Z = P, As, and Sb, respectively. Thermoelectric properties of the RbCaCZ (Z = P, As, Sb) materials are additionally computed over an extensive variety of temperature and it is discovered that all compounds demonstrates higher figure of merit. The half-metallic structures of these compounds with large band gaps and adequate Seebeck coefficients mean that they are suitable for use in spintronic and thermoelectric device applications.

5 illus, 3 tables, 30 ref

042545   ABDUL-HAFIDHA E H, ALSADI K S (Physics Dep, Faculty of Science at Taibah Univ-Madina, Prince Naif St, 47444, Saudi Arabia, Email: ksaede@taibahu.edu.sa) : Size and structure dependence of the anomalous bulk modulus for FCC metallic nanoparticles. Indian J Pure Appl Phys 2020, 58(11), 812-7.

The purpose of this work is to develop a theoretical model to calculate the bulk moduli of FCC nanoparticles that account for their size and structure. The bulk modulus for spherical nanoparticles has been derived from the cohesive energy which had been calculated by summing up the potential energy function of every pair of atoms of these metallic nanoparticles. The ab initio pair potential energy function has been formed by inverting the cohesive energy function proposed by (Rose et al., 1981), using the Chen-Mobius method. The results show that, as the size decreases, the bulk modulus decreases for spherical nanoparticles, which agrees with previous experimental and theoretical predictions. The results also predicted an “amorphous” structure for ultra-small nanoparticles and were consistent with previous experimental work.

4 illus, 1 table, 49 ref

042543   BHAVSAR V, TRIPATHI D (Applied Sciences and Humanities Dep, Gujarat Technological Univ, Ahmedabad, Gujarat, Email: vaishali.b.bhavsar@gmail.com) : Study of biocompatible polymer blend films with tuneable band gap. Indian J Pure Appl Phys 2020, 58(11), 795-803.

In present communication, an attempt is made to prepare and study structural, optical, and electrical properties of biocompatible polyvinylchloride (PVC)-polyvinylpyrrolidone (PVP) blend films taken in ratio of 1:1 doped with conducting polymer Polypyrrole (PPy).The XRD spectra revealed amorphous nature of all the films under investigation. The Fourier transform infra-red spectroscopy (FTIR) study of conducting polymer doped blend films indicate a significant change in the intermolecular/intramolecular interactions taking place. The study on electrical properties of conducting polymer doped blend films show better conduction of current as compared to that of blend film without conducting polymer and dopant concentration dependent electrical conductivity and conduction mechanism. The results of optical study of conducting polymer doped blend films revealed the possibility of band gap modification from wide band gap to small band gap with suitable doping concentration. These biocompatible blend films with tuneable optical and electrical properties can be potential material for use in fields of photonic biosensors, solar cell and optoelectronics field.

10 illus, 2 tables, 35 ref

042541   NEGI J, SINGH S, PANWAR N S (HNB Garhwal Univ, Srinagar (Garhwal)-246 174, Email: jyotsana.jn42@gmail.com) : Electrical Properties of lead free ceremics Na_1−XK_xNbO₃, at x=0.305.. Indian J Pure Appl Phys 2020, 58(11), 783-6.

By solid state reaction method, ceramic pellets of Na_0.695K_0.305NbO₃ have been prepared. X-ray- diffraction, Piezo properties, scanning electron microscope, and temperature dependence of dielectric constant and loss tangent of the prepared samples have been studied. It has been observed that, at the transition temperature, dielectric constant peak shifts to lower temperature, and the dielectric constant and loss tangent peak heights decrease, with increasing frequency, and show three structural phase transitions.

7 illus, 23 ref

042540   BAGYARAJ S, APURVA S , ASHA R , SANGEETHA B, VAITHIYANATHAN D (Biomedical Engineering Dep, Sri Sivasubramaniya Nadar Coll of Engineering, Kalavakkam-603 110, Email: bagyarajs@ssn.edu.in) : Brain wave classification for divergent hand movements. Indian J Pure Appl Phys 2020, 58(10), 765-73.

Brain-Computer Interface (BCI) is an emerging technology in medical diagnosis and rehabilitation. In this study, by the acquisition of Electroencephalogram (EEG) signals from 30 healthy participants who perform four different hand movements, necessary features are extracted and classified to determine their accuracies. Statistical time domain features are extracted from the mu and beta frequency band. The Event related desynchronization (ERD)/Event related synchronization (ERS) measurements are extracted, from which it was evident that both mu and beta frequency bands are more efficient in the C3 channel. By applying the Paired Samples t-test, the extracted features are analyzed and were determined to have a 95 % significant level of difference between the mu and beta band, being statistically efficient in the beta band of the C3 channel. By employing different classifiers such as Support Vector Machine (SVM), Linear Discriminant Analysis (LDA), Quadratic Discriminant Analysis (QDA), Naïve Bayesian classifier and Binary Decision Tree (BDT) algorithms on both channel’s mu and beta frequency bands, it was observed that the performance of beta frequency band classifiers shows 90% accuracy in binary class classification. In the comparative study of all these classifiers, LDA and Naïve Bayes show above 95 % accuracy for binary class classification.

5 illus, 3 tables, 26 ref

042539   DEVAKI P, RAO A S, SHARMA R P, SREENADH S (Mechanical Engineering Dep, National Institute of Technology, Yupia, Arunachal Pradesh, Email: rpsharma@nitap.ac.in) : Impact of hematocriton the flow of casson fluid in contact with jeffery fluid over a narrow pipe. Indian J Pure Appl Phys 2020, 58(10), 758-64.

The flow of Casson fluid in contact with Jeffery fluid in a tube with a small diameter is concentrated in this paper. Casson fluid is considered in the central region and Jeffery fluid in the outer region. The governing equations are solved analytically and obtained expressions for velocity, flux, effective viscosity, central hematocrit, and mean hematocrit in dimensional form. The effect of many physical parameters on velocity, flux, effective viscosity, central hematocrit, and mean hematocrit is observed through graphs. Central hematocrit increases with an increase in yield stress and hematocrit and means hematocrit decreases with an increase in yield stress and hematocrit. The paper finds its applications in the flow of blood in narrow arteries, vines, and capillaries. The problem warrants further study on the flow of non-Newtonian two-fluid flows in a narrow tube.

15 illus, 27 ref

042538   SULAIMAN S M , JAISON B , BENNET M A, VAITHIYANATHAN D (Electronics and Communication Engineering Dep, Vel Tech High Tech Dr. Rangarajan Dr. Sakunthala Engineering Coll, Chennai – 600 062, Tamil Nadu, Email: sulaimanmtech@gmail.com) : Adaptation of counters redundant bits with the provision of dual supply and modified clock gating to favour of low power in VLSI. Indian J Pure Appl Phys 2020, 58(10), 750-7.

The utilization of usual supply voltage and clock for repetitive state transistors in digital circuits is a fundamental driver for high power utilization. Most significant bit states of the counter stay longer than the least significant bit states and it has some repetitive states. To limit the supply voltage and stop the clock for MSB Flip Flop (FF) transistor, our method uses Control Combinational Logic, Voltage selector and Modified Integrated Clock Gating blocks. The LSB transistor always have a supply voltage of 1.2V and succession of the clock, while MSB transistor gets just 480mV and the clock will be stopped by the this technique. Bring down the supply voltage and quit the clock for redundant states either 0 or 1 in MSB. Meantime supply 1.2V and clock for state changes over from one state to next state. The experimental simulation was done in 45nm CMOS technology using Cadence virtuoso indicates that this asynchronous counter achieves a power savings of 23.57 % and the same modified technique when applied to the counters with transmission-gate FF, hybrid-latch FF and sense amplifier FF will have more than 40% power savings and the technique applied in some benchmark circuits will have more than 22 % power savings than existing techniques.

10 illus, 3 tables, 23 ref

042537   TANWAR P , SINGH S, PANWAR A K, SRIVASTAVA A K (CSIR - National Physical Laboratory, Dr. K. S. Krishnan Road– 110 012, New Delhi, Email: panwaramar@gmail.com) : Synthesis and characterization of crystalline polyaniline. Indian J Pure Appl Phys 2020, 58(10), 740-9.

Remarkable enhancement in figure-of-merit (ZT) value of p-type Tin Telluride (SnTe) thin films is reported in the present investigations. Under high vacuum conditions, all thin films deposited on the glass substrate by using thermal evaporation technique. Thickness of the thin films were kept 55 and 33 nm. Morphological features and the elemental composition of the thin film were investigated using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) technique respectively. High-resolution transmission electron microscopy (HRTEM) with selected area electron diffraction (SAED) pattern was used to investigate the microstructure of these thin films. For the identification of crystalline features, phase, and nano-crystallites size in all the thin films, the X-ray diffraction (XRD) technique had played a dominant role. The analysis of the XRD data results in a single-phase cubic structure. Atomic force microscopy (AFM) analysis revealed the 2D and 3D view of variable size grains formed on the glass substrate. Four probes method was used to determine the electrical conductivity of these thin films. Electrical measurements revealed the semi-metallic nature of the SnTe thin films. The thermoelectric measurement analysis revealed that the ZT of the thin films was found to be increased as the thickness of the film enhanced. The maximum value of ZT∼1.0 was obtained at room temperature for the film of thickness 55 nm.

8 illus, 4 tables, 48 ref

042536   SINGH B, DAS B (Physics Dep, Lucknow Univ, Lucknow-226 007, Email: bharti.singh26@yahoo.com) : Synthesis and characterization of crystalline polyaniline. Indian J Pure Appl Phys 2020, 58(10), 735-9.

The present paper deals with the synthesis and characterization of crystalline polyaniline (PANI). In the present work the crystalline PANI was synthesized in two steps. Firstly, the amorphous polyaniline was prepared by co-precipitation method using aniline as precursor and ammonium peroxodisulfate as reagent. In second stage the crystalline PANI was prepared by the melting and slow cooling. Pellets of PANI were prepared at pressure of 3000-4000 kg/cm². The resulting crystalline PANI was characterized by powder X-ray diffraction (PXRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM). The PXRD pattern confirms the crystalline behaviour of PANI. The AFM results also support PXRD result due to presence of tiny crystals on the surface of PANI. TEM analysis reveals various nanorings connecting the characteristics diffraction spots of PANI nanoparticles.

5 illus, 2 tables, 14 ref

042535   KENNEDY A, KUMAR V S, RAJ K P (Physics Dep, CSI Coll of Engineering, Ooty – 643 215, Email: kennedycsice@gmail.com) : Influence of substrate temperature on physical properties of MnSbInS4 thin films prepared by a simplified spray pyrolysis technique for photovoltaic applications. Indian J Pure Appl Phys 2020, 58(10), 726-34.

MnSbInS₄ multi-component semiconductor thin films are prepared by chemical spray pyrolysis on glass substrates at various substrate temperatures ranging from 250-400 °C with a constant spray time (5mins). The structural, morphological, optical and electrical properties of the thin films are investigated through different techniques such as X-ray diffraction (XRD), electron diffraction spectroscopy (EDS), UV-Vis absorption spectroscopy and four probe method. The X-ray spectra reveal that the MnSbInS₄ films are polycrystalline in nature with a cubic spinel structure having (220) plane as the preferred orientation. The energy dispersive analysis by X-ray (EDS) studies confirm the presence of Mn, In, Sb and S in the film grown at a substrate temperature of 250 °C. Optical measurements allow us to determine the absorption coefficient which is as high as (1.22 x 10⁵ cm^-1) at 250 ºC indicating that MnSbInS₄ compound has an absorbing property favorable for applications in solar cell devices. It is interesting to note that the structural homogeneity and crystallinity of the films is improved due to the decrease in absorption coefficient (α) and extinction coefficient (k) with an increase of substrate temperature. The observations from photoluminescence measurements reveal that the photoemission is mainly due to the donar-acceptor pair transitions. Moreover, from the electrical studies, it is observed that the electrical resistivity (ρ ) is strongly affected by substrate temperature and the lowest resistivity (ρ = 4.77 x 10³ Ω m ) is obtained for the film grown at 400 ºC. Stylus profilometer was used to measure the film thickness and the values range between 768 nm (250 °C) to 617 nm (400 °C). This indicates that, as the substrate temperature increases, the thickness of the film decreases. Other important parameters like micro-strain (ε) and dislocation density (δ) which are commonly used to describe the structural analysis are also presented.

8 illus, 4 tables, 86 ref

042534   PAUL S N, CHOWDHURY A R (Physics Dep, Jadavpur Univ, Kolkata - 700 032, Email: drsnpaul@gmail.com) : Modulational instability of bright envelope soliton and rogue waves in ultrarelativistic degenerate dense electron-ion-positron plasma. Indian J Pure Appl Phys 2020, 58(10), 715-25.

Modulational instability and bright envelope solitons of ion acoustic waves in dense plasma consisting of ultra-relativistic degenerate electrons and positrons, cold and mobile inertial ions, and negatively charged static dust particles have been investigated using Fried and Ichikawa method. Nonlinear Schrodinger equation has been derived and the growth rate of modulationally unstable ion acoustic wave in such plasma is discussed. It has been found that ion acoustic wave will be always modulationally unstable for all possible values of density of positrons, electrons and charged dust particle but there is no instability of the wave for any value of plasma parameters in such plasma. The solutions of ion acoustic envelope- solitons and rogue waves are obtained from the Nonlinear Schrodinger equation. The theoretical results have been analyzed numerically for different values of plasma parameters and the results are presented graphically. It is found that only bright envelope soliton would be excited in the ultra-relativistic plasma. Our results are new and may be applicable for the study of nonlinear wave processes in relativistic degenerate dense plasmas of astrophysical objects, namely, in white dwarfs and neutron stars.

5 illus, 37 ref

042533   ANMOL, PANDIT S (Indian Institute of Information Technology Design and Manufacturing, Jabalpur - 482 005, Email: 1814005@iiitdmj.ac.in) : New hand-cart for Old-Delhi whole sale market designed and engineered using generic product development process. Indian J Pure Appl Phys 2020, 58(9), 698-705.

The study aimed to design a hand cart for the cart puller in the old Delhi area. We used a Generic Product Development Process as a base to design and test our new cart design for the cart pullers. The process had been used in a sequential procedure to get the best design solution. It also saves time and money which would be wasted in the reiteration of the cart design. It starts with User Research where we find out the basic user needs, which can be conducted via interview. Then to convert the user needs into applicable design specifications, we used a Quality Function Deployment (QFD). The next stage was to design the concepts, to do so we used the Morphological chart which helped us to generate concepts logically. After the generation of concepts, we had to select one concept which is the most promising one, to do so we used Pugh’s Concept Selection method and we landed on one concept. To make the detailed design of the cart we used dimensions from the existing cart and used Indian anthropometric data to add ergonomics into the cart design. A 3D CAD Design was made using detailed dimensions. Finally, based on CAD design a low fidelity prototype was made, and then it was translated into a 1:1 scale prototype. The last stage of testing was done and results were compared with the existing cart design in terms of Rapid Entire Body Assessment (REBA), Hierarchical Task Analysis (HTA) and Verbal interview.

10 illus, 4 tables, 15 ref

042531   CHANDRA A, CHANDRA A , DHUNDHEL R S , JAIN A , THAKUR K , THAKUR S S , BASAK S , KHAN M Z , BHATT A (Shri Shankaracharya Institute of professional Management and Technology, Raipur - 492 015, Chhattisgarh, Email: chandrassi@gmail.com) : Silver ion conducting solid polymer electrolytes: Synthesis and ion transport studies. Indian J Pure Appl Phys 2020, 58(9), 686-90.

A new silver ion conducting Polyethylene Oxide (PEO) based solid polymer electrolyte (SPE) films:  (1-x) PEO: xAgCl, where 0<x<70 in wt. %, are synthesized by using a new hot-press and traditional solution-cast techniques. The electrical conductivity of the SPE increased with the concentration of salt AgCl. The optimum conducting composition (OCC): 70PEO: 30AgCl with ionic conductivity (σ) 6.0 × 10⁻⁷ Scm^-1 have been determined at room temperature. The increase in ionic conductivity has been explained with the help of ionic mobility (µ) and mobile ion concentration (n) studies. To explain the ionic nature of the present system, ionic transference number (t_ion) measurement has been carried out at room temperature.

6 illus, 1 table, 30 ref

042530   ADHIKARI M S, PATEL R , TRIPATHI S L, SINGH Y (Lovely Professional Univ, Punjab, Email: manoj.space99@gmail.com) : Design of SOI MOSFETs for analog/RF circuits. Indian J Pure Appl Phys 2020, 58(9), 678-85.

In this paper, the concept of integration of a high voltage trench MOSFET (HVT MOSFET) and low voltage trench MOSFET (LVT MOSFET) is proposed. Insulator (Dielectric) isolation technique is used for the implementation of HVT and LVT MOSFETs on Silicon-on-Insulator (SOI) layer side by side. The HVT MOSFET consists of two gates which are placed in separate trenches in the drift region. The proposed structure minimizes ON-resistance (R_on) along with increased breakdown voltage (V_br) due to reduced electric field, creation of dual channels, and folding of drift region in vertical direction. In HVT MOSFET, the drain current (ID) increases leading to enhanced trans conductance (g_m) by simultaneous conduction of channels which improves the cut-off frequency (f_t ) and maximum oscillation frequency (f_max). On the other side, LVT MOSFET consists of a gate placed within a SiO₂ trench to create two channels on either side of gate. The parallel conduction of two channels provides enhancement in I_D, g_m, f_max and f_t . The performance analysis of HVT MOSFET and LVT MOSFET is carried out using 2D simulation in the device simulator (ATLAS).

15 illus, 1 table, 24 ref

042530   MAIBAM B , BARUAH S , SINGH B P, KUMAR S (Physics Dep, Rajiv Gandhi Univ, Doimukh, Itanagar, Email: sanjeev.kumar@rgu.ac.in) : Quantitative analysis of Fe/Co co-doped ZnO by rietveld method. Indian J Pure Appl Phys 2020, 58(9), 673-7.

Fe/Co co-doped Zinc oxide was prepared by using hydrothermal method. Refinement of recorded X-ray diffractograms was done by Rietveld method by using MAUD. It shows that all the samples have a hexagonal structure with space group P63mc and the average crystallite size of the samples lie between 49-79 nanometers. Presence of some secondary phases were also detected. Rietveld analysis data reveals that the density of the doped and co-doped ZnO is more than the pristine ZnO. The goodness of fit value ranges from 1.3875-1.7519. The unit cell volume decreases for the doped and co-doped ZnO as the value of lattice parameter decreases with doping and co-doping. Decrease in the interplaner spacing values may be because of the strain developed in the lattice due to doping and co-doping.

3 illus, 3 tables, 20 ref

042529   PATEL S S, MISTRY B V, ZINZUVADIYA S, JOSHI U S (Physics Dep, Gujarat Univ, Ahmedabad - 380 009, Email: usjoshi@gmail.com) : Photon irradiation effects on electrical properties of n-ZnO/p-Si junctions for optoelectronic device. Indian J Pure Appl Phys 2020, 58(9), 667-72.

Simple high energy laser photon irradiation is a handy tool to tune the functional properties of wide band gap oxide-based devices. Present study reports on the effects of laser photon irradiation on electrical transport behaviour of n-ZnO/p-Si p-n junctions. The n-type conductivity of ZnO was optimised by doping of stoichiometric amount of Al in ZnO. The n-ZnO/p-Si junctions were grown on p-Si (100) substrate by pulsed laser deposition. The structural property was analysed by X-ray diffraction. Morphological study was done using atomic force microscopy (AFM) which shows smooth and mono-dispersed surfaces of the p-n junction. The current-voltage (I-V) characteristic of the n-ZnO/p-Si devices have been measured at room temperature in the dark and under illumination. Moreover, the effects of 532 nm visible laser light irradiation on the electric parameter of n-AZO/p-Si p-n junctions were investigated. The characteristic parameters of the junctions such as barrier height, ideality factor and series resistance were determined from the current-voltage measurement. The results show a promise of ZnO based diode structure for its optoelectronic applications.

6 illus, 1 table, 26 ref