005121   HU Y, PODOLEANU A, DOBRE G (Kent Univ, Kent Univ, Canterbury, United Kingdom, Email: y.hu-240@kent.ac.uk) : Photothermal optical coherence tomography for investigation and imaging photothermal trapping of gold nano-rods in clear media and biological tissue. J Opt 2019, 21(9), 095301.

A quantitative spectrometer-based photothermal optical coherence tomography (PT-OCT) system is employed to investigate and image the photothermal trapping of gold nano-rods (GNRs) in clear and biological media. The PT-OCT system is calibrated through dynamic phase measurements of piezo motion with known driving parameters. We measure and compare the displacement sensitivities of the PT-OCT system at different camera exposure time settings in two configurations: with a distinct reference path; and with a common path. The displacement sensitivity of the system in the common path configuration is improved from 1.5 to 0.17 nm by performing Fourier analysis on the output phase. The minimum Ti:Sa power capable of inducing a detectable photothermal response of GNRs is measured to be 0.5 mW. This value agrees with the latest reported minimum Ti:Sa power for photothermal trapping GNRs. The PT-OCT system is used to generate en-face images of photothermal trapped GNRs in the water solution and in the biological tissue. By displaying the difference between successive en-face phase images, spatial distribution patterns of the aggregated GNRs, resulted from the photothermal trapping, are clearly outlined with great contrast. The photothermal trapping of GNRs in tissue shows a greater complexity than in the clear media. The limitation of the PT-OCT technology is discussed. The study proves the potential of PT-OCT for imaging the photothermal trapping of GNRs.

12 illus, 39 ref

005112   BARCO O D, SOLA I J, JARQUE E C, BUENO J M (Murcia Univ, Murcia, Spain, Email: obn@um.es) : Dielectric mirror optimization based on the phase-compensation method. J Opt 2019, 21(9), 095101.

A phase-compensation method is presented to fully optimize multilayer reflectance bandwidth, spectral phase and group delay dispersion. For a given multilayer (A), a set of different phasecompensated dielectric mirrors (B) is achieved as a function of a single parameter: the so-called reference wavelength λr. With a correct selection of the parameter λr, a set of different dielectric multilayers can be obtained with fixed broadband reflectance regions and smooth spectral phases (independently of the layers’ thickness distribution) so that ultrashort pulses can be entirely reflected in such dielectric mirrors with a negligible amount of absorption and distortion. Hence, with an adequate numerical analysis via our phase-compensation method, experimental designs can be easily performed to obtain ad hoc dielectric mirrors for ultrashort pulse management.

5 illus, 38 ref

005118   HE X, NING T, ZHENG J, LI J, PEI L, WU B (Beijing Jiaotong Univ, Beijing- 100 044, People’s Republic of China, Email: lipei@bjtu.edu.cn) : Deep-subwavelength light transmission in hybrid graphene-dielectric slot waveguide. J Opt 2019, 21(9), 095001.

In this paper, a novel hybrid graphene-dielectric slot waveguide (HGDSW) is theoretically proposed. The characteristics of the fundamental hybrid modes (TM polarization) including effective refractive index (n_eff), normalized mode area (A_eff/A₀), propagation length (L_p) and figure of merit are numerically investigated. The results reveal the hybrid mode guided in the proposed HGDSW can be tuned by the key geometric structure parameters and the chemical potential of graphene. Besides, the HGDSW can support low loss and effective deep subwavelength light transmission in THz wavelength, in conjunction with enhanced overall high performance. Moreover, ultra-low crosstalk between two parallel HGDSWs can be achieved. The HGDSWs reveal the potential capabilities in the ultra-compact photonic integration field.

6 illus, 1 table, 50 ref

005115   CRIMIN F, MAKKINNON N, GOTTE J B, BARNETT S M (Physics and Astronomy Dep, Glasgow Univ, Glasgow G12 8QQ, United Kingdom, Email: frances.crimin@glasgow.ac.uk) : On the conservation of helicity in a chiral medium. J Opt 2019, 21(9), 094003.

We consider the energy and helicity densities of circularly polarised light within a lossless chiral medium, characterised by the chirality parameter β. A form for the helicity density is introduced, valid to first order in β, that produces a helicity of ±ÿ per photon for right and left circular polarisation, respectively. This is in contrast to the result obtained if we use the form of the helicity density employed for linear media. We examine the helicity continuity equation, and show that this modified form of the helicity density is required for consistency with the dual symmetry condition of a chiral medium with a constant value of ò/μ. Extending the results to arbitrary order in β establishes an exact relationship between the energy and helicity densities in a chiral medium.

1 illus, 26 ref

005114   BIALYNICKI-BIRULA I (Polish Academy of Sciences, Warsaw, Poland, Email: birula@cft.edu.pl) : Helicity amplitudes, polarization of EM waves and stokes parameters: Classical versus quantum theory. J Opt 2019, 21(9), 094002.

It is shown that the helicity amplitudes can be used to describe and analyze the properties of the electromagnetic field in classical and in quantum theory. On the one hand they embody the relativistic content of electromagnetic theory. On the other hand they give a concise description of such experimentally important notions as polarization, the Stokes parameters and the Poincaré sphere.

12 ref

005129   PAUFLER W, BONING B, FRITZSCHE S (Helmholtz Institute, Jena, Germany, Email: willi.paufler@uni-jena.de) : High harmonic generation with Laguerre– Gaussian beams. J Opt 2019, 21(9), 094001.

We summarize the development of high harmonic generation (HHG) with linearly polarized Laguerre–Gaussian (LG) beams and their superpositions to explain the non-perturbative aspects of HHG. Furthermore, we show that circularly polarized extreme ultraviolet vortices with welldefined orbital angular momentum (OAM) can be generated by HHG with bicircular LG beams. We introduce photon diagrams in order to explain how to calculate the OAM and the polarization of the generated harmonics by means of simultaneous conservation of spin angular momentum and OAM. Moreover, we show how the intensity ratio of the driving fields in HHG with bicircular LG beams further enhances the generation of circularly polarized twisted attosecond pulse trains.

9 illus, 38 ref

005137   WU Z, LI P, ZHANG Y, GUO H, GU Y (Henan Univ, Kaifeng- 475 004, People’s Republic of China, Email: wuzk1121@163.com) : Multicharged vortex induced in fractional schrödinger equation with competing nonlocal nonlinearities. J Opt 2019, 21(10), 105602.

This study analytically and numerically investigates the evolution of an optical vortex beam carrying topological charges (TCs) in a fractional Schrödinger equation with competing nonlocal nonlinearities. Results show that the number of beads, TCs, and size of the incident beam significantly affect vortex production and evolution. Common rules formulated based on various incident beams determine the number of induced vortices and corresponding rotation direction. The beams gradually expand to induce vortices in oppositely charged pairs during propagation, thus conserving the vortex’s net TC. The demonstrated optical vortex is significant for quantum information communication and optical imaging and processing applications.

5 illus, 49 ref

005113   BHATTACHARJEE A, SAHU R, JHA A K (Physics Dep, Indian Institute of Technology, Uttar Pradesh- 208 016, Email: akjha9@gmail.com) : Generation of a gaussian schell-model field as a mixture of its coherent modes. J Opt 2019, 21(10), 105601.

Gaussian Schell-model (GSM) fields are examples of spatially partially coherent fields which in recent years have found several unique applications. The existing techniques for generating GSM fields are based on introducing randomness in a spatially completely coherent field and are limited in terms of control and precision with which these fields can be generated. In contrast, we demonstrate an experimental technique that is based on the coherent mode representation of GSM fields. By generating individual coherent eigenmodes using a spatial light modulator and incoherently mixing them in a proportion fixed by their normalized eigenspectrum, we experimentally produce several different GSM fields. Since our technique involves only the incoherent mixing of coherent eigenmodes and does not involve introducing any additional randomness, it provides better control and precision with which GSM fields with a given set of parameters can be generated.

5 illus, 33 ref

005131   SCHUKAREV I, KOROBKO D, ZOLOTOVSKII I (Ulyanovsk State Univ, Ulyanovsk, Russia, Email: korobkotam@rambler.ru) : Parabolic pulse generation in short fiber amplifiers. J Opt 2019, 21(10), 105505.

The evolution of a laser pulse in a normal dispersion fiber amplifier is studied numerically. The cases of amplification with ideal spectrally flat gain and amplification with spectrally parabolic gain are considered. It is shown that the transformation of the input pulse envelope into parabolic form is possible, not only for spectrally flat but also for spectrally limited gain. In the last case, the important parameter is the optimal length of the amplifier. The results show that for a sufficiently broadband gain, it is always possible to find the optimal amplifier length, which provides the output pulse with envelope close to the parabola.

4 illus, 1 table, 24 ref

005117   FINOT C, RIGNEAULT H (BourgogneFranche-Comte Univ, Dijon Cedex, France, Email: christophe.finot@u-bourgogne.fr) : Arago spot formation in the time domain. J Opt 2019, 21(10), 105504.

Using the space-time duality, we theoretically and experimentally revisit the Arago spot formation in the time domain and explore the temporal emergence of a bright spot in the time shadow of an initial waveform. We describe the linear regime of propagation using Fresnel’s integrals and show that in the presence of Kerr nonlinearity the Arago spot formation is affected depending on the sign of the dispersion. We finally confirm experimentally the Arago spot formation in the time domain using a telecommunication optical fiber platform.

9 illus, 41 ref

005138   ZHANG F-D, WANG X-S, CAI P-C, TAN Y, CAI H-X, LIN J-Q, JIN G-Y, HE G S (Changchun Univ of Science and Technology, Changchun- 130 022, People’s Republic of China, Email: linjingquan@cust.edu.cn) : Dynamic properties of ultrashort two-photon pumped transient cavityless lasing in a coumarin-dye solution. J Opt 2019, 21(10), 105502.

The dynamic spectral and temporal properties of femtosecond two-photon pumped frequency upconversion lasing in a Coumarin-500 dye solution are presented. Forward and backward lasing in a 1 cm pathlength dye solution with a concentration of 0.1 M occurs at wavelengths of 491 nm and 493.5 nm, respectively, whereas the peak wavelength of the ordinary steady-state fluorescence emission is at 513 nm. There is a real-time delay of ∼2 ps between the forward pump pulse peak and the first burst of the two-photon pumped forward lasing pulse, which corresponds to the build-up time of the effective population inversion sufficient for transient lasing. In contrast, the backward output lasing pulse can involve two temporally separate components, i.e. the original backward lasing pulse as well as an additional component, due to the reflection of the forward lasing pulse from the output window. At much higher pump levels than the threshold, the output/input characteristic curve deviates from the quadratic law. The physical explanations for these experimental results are proposed.

9 illus,37 ref

005128   MOHAMMADNEZHAD M, SAEED S R, HASSANZADEH A (Physics Dep, Kurdistan Univ, Kurdistan, Iran, Email: a.hassanzadeh@uok.ac.ir) : Theoretical simulation of gaussian beam interferometric optical tweezers with symmetrical construction. J Opt 2019, 21(10), 105404.

Multi-beam optical tweezers can be very effective and suitable for creating optical lattices and dexterous manipulation of the microscopic world. In an earlier work, a symmetrical multi-beam optical tweezers setup was proposed and theoretically investigated. In that study, however, we assumed that the incident beams were plane waves, and a plane wave cannot exist in real situations. The main aim of this paper is to investigate multi-beam optical tweezers under the realistic condition of using the Gaussian beams. The effects of changing the polarization state and the number of incident beams on potential landscapes are investigated. A comparison between the Gaussian beam and plane wave lattices is also performed. The results show that in the case of p-polarization, a very small spot (a sub-λ spot) can be achieved by increasing the number of incident beams. However, for s-polarized incident beams instead of a bright center, a dark center intensity distribution is obtained. The lattices constructed by the interference of the Gaussian beams have deeper traps in the central region compared to the plane wave lattices.

7 illus, 31 ref

005134   STOYANOVA E, AL-MAHMOUD M, HRISTOVA H, RANGELOV A, DIMOVA E, VITANOV N V (Physics Dep, Sofia Univ, Sofia- 1164, Bulgaria, Email: e.dimova@issp.bas.bg) : Achromatic polarization rotator with tunable rotation angle. J Opt 2019, 21(10), 105403.

We theoretically suggest and experimentally demonstrate a broadband composite optical rotator that is capable of rotating the polarization plane of a linearly-polarized light at any chosen angle. The device is composed of an even number of half-wave plates (WPs) rotated at specific angles with respect to their fast-polarization axes. The frequency bandwidth of the polarization rotator in principal increases with the number of half-WPs. Here we experimentally examine the performance of rotators composed of two, four, six, eight and ten half-WPs.

2 illus, 2 tables, 13 ref

005123   KHAN M I, ALI T, ALI H, ZUBAIR M, AHMAD I, SHAFIQ M, AHMAD P, REHMAN F, SAEED Y (Physics Dep, Abbottabad Univ of Science and Technology, Havelian, Pakistan, Email: yamanuom@gmail.com) : Control of the faraday rotation via electromagnetically induced transparency medium and graphene metasurfaces. J Opt 2019, 21(10), 105401.

We investigate theoretically the control over Faraday rotation via an electromagnetically induced transparency medium (EIT) and graphene metasurfaces. The Faraday rotation of the light pulse is enhanced with increased probe field detuning. The increasing strength of the magnetic field enhances the rotation of the polarization plane and shifts its zero crossing at a higher frequency. The increase in the chemical potential rotates the polarization plane of the light pulse propagating through the system at low frequency. The periodic arrangement of disks on a graphene metasurface enhances the Faraday rotation of the light pulse and shifts the zero crossing relatively at a low frequency. The chemical potential, magnetic field and periodic length of disks can be used to control the Faraday rotation of light pulses at the desired frequency.

7 illus, 34 ref

005133   SIABER S, ZONETTI S, SYDORUK O (Imperial Coll, London, United Kingdom, Email: osydoruk@imperial.ac.uk) : Junctions between two-dimensional plasmonic waveguides in the presence of retardation. J Opt 2019, 21(10), 105002.

Plasmons in two-dimensional (2D) waveguides are traditionally analysed within the electrostatic approximation, which assumes that the plasmon phase velocity is much smaller than the velocity of light. However, novel effects have recently been demonstrated for plasmons whose velocity is comparable to the velocity of light. In this retardation regime, electrostatic models are inaccurate. For a junction between two plasmonic waveguides, we present an analytical and a numerical model both valid in the retardation regime and compare them to an electrostatic model. We quantify the reflected and transmitted powers and the radiation loss in several scenarios. We found that power is radiated from a junction at the expense of the power of the reflected plasmon, but retardation has little effect on the phases of the reflected and transmitted plasmons. The radiation loss is typically below several percent when the plasmon velocities are five or more times below the light velocity. However, radiation still persists for slower plasmon velocities for a junction between a 2D waveguide and a perfectly conducting sheet. As a result, retardation is expected to degrade the quality factors of plasmonic resonators without affecting their eigenfrequencies

8 illus, 31 ref

005124   KOKSAL K, LEMBESSIS V E, YUAN J, BABIKER J (Physics Dep, Bitlis Eren Univ, Bitlis- 13100, Email: meb6@york.ac.uk) : Interference of axially-shifted Laguerre– Gaussian beams and their interaction with atoms. J Opt 2019, 21(10), 104002.

Counter-propagating co-axial Laguerre–Gaussian (LG) beams are considered, not in the familiar scenario where the focal planes coincide at z = 0, but when they are separated by a finite axial distance d. The simplest case is where both beams are doughnut beams which have the same linear polarisation. The total fields of this system are shown to display novel amplitude and phase distributions and are shown to give rise to a ring or a finite ring lattice composed of double rings and single central ring. When the beams have slightly different frequencies the ring lattice pattern becomes a finite set of rotating Ferris wheels and the whole pattern also moves axially between the focal planes. We show that the fields of such an axially shifted pair of counter-propagating LG beams generate trapping potentials due to the dipole force which can trap two-level atoms in the components of the ring lattice. We also highlight a unique feature of this system which involves the creation of a new longitudinal optical atom trapping potential due to the scattering force which arises solely when d is not equal to 0. The results are illustrated using realistic parameters which also confirm the importance of the Gouy and curvature effects in determining the ring separation both radially and axially and gives rise to the possibility of atom tunnelling between components of the double rings.

4 illus, 29 ref

005120   HOLMES B M, GALVEZ E J (Physics and Astronomy Dep, Colgate Univ, New York- 13346, Email: egalvez@colgate.edu) : Poincare bessel beams: Structure and propagation. J Opt 2019, 21(10), 104001.

Non-separable superpositions of polarization and spatial modes in Gaussian beams have shown rich patterns of spatially-variable polarization encoded in the transverse mode of the light, with the potential for many applications. In this work, we investigate encoding similar types of superpositions in Bessel beams. We find that analogously to what is observed in Poincaré– Gaussian beams, Poincaré–Bessel beams can be produced by Bessel-mode superpositions. They show polarization patterns with disclinations in the orientation of the polarization ellipse and mappings of the Poincaré sphere onto the transverse mode. We report on the observation of lemons, stars and monstar disclinations in the multi-ringed profile of Bessel modes. By manipulating the angular spectrum of the component Bessel beams, we are able to impart linear rotation of the patterns along the non-diffracting range due to a linearly increasing propagation phase difference.

6 illus, 53 ref

005132   SHINE N S, PARAMU R, GOPINATH M, BOS R C J, JAYADEVAN P M (Physics Dep, Banasthali Univ, Jaipur, Rajasthan, Email: shinenairns@gmail.com) : Out of field dose calculation by a commercial treatment planning system and comparison by monte carlo simulation for varian truebeam. J Med Phys 2019, 44(3), 156-75.

The calculation accuracy of treatment planning systems (TPSs) drops drastically when the points outside the field edges are considered. The real accuracy of a TPS and linear accelerator (linac) combination for regions outside the field edge is a subject which demands more study. In this study, the accuracy of out‑of‑field dose calculated by a TPS, used with a TrueBeam® (TB) linac, is quantified. For dose calculation, Eclipse™ version 13.7 commissioned for TB machine was used. For comparison, Monte Carlo (MC) methods, as well as the measurements, were used. The VirtuaLinac, a Geant 4‑based MC program which is offered as a cloud solution, is used for the generation of input phase‑space (PS) files. This PS file was imported into PRIMO (PENELOPE based MC program) for the simulation of out‑of‑field dose. In this study, the accuracy of the out‑of‑field dose calculated by a TPS for a TB linac was estimated. As per the results in comparison with MC simulations, the TPS underestimated the dose by around 45 % on an average for the off‑axis‑distance range considered in this study. As the off‑axis distance increased, the underestimation of the dose also increased. In this work, it was observed that the TPS underestimates doses beyond the edges of treatment fields for a clinical treatment executed on a TB machine. This indicates that the out‑of‑field dose from TPSs should only be used with a clear understanding of the inaccuracy of dose calculations beyond the edge of the field. 

10 illus, 3 tables, 28 ref

005119   HOLLA R, KHANNA D, PILLAI B K, ALI K V J, MON P S R, CLINTO C O, GANESH T (Physics Dep, Karunya Institute of Technology and Sciences, Coimbatore - 641 114, Email: davidkhanna@karunya.edu) : An experimental slope method for a more accurate measurement of relative radiation doses using radiographic and radiochromic films and its application to megavoltage small field dosimetry. J Med Phys 2019, 44(3), 145-55.

An experimental method using the linear portion of the relative film dose–response curve for radiographic and radiochromic films is presented, which can be used to determine the relative depth doses in a variety of very small, medium, and large radiation fields and relative output factors (ROFs) for small fields. The film slope (FS) method was successfully applied to obtain the percentage depth doses (PDDs) for external beams of photon and electrons from a Synergy linear accelerator (Elekta AB, Stockholm, Sweden) under reference conditions of 10 cm × 10 cm for photon beam and nominal 10 cm × 10 cm size applicator for electron beam. For small‑field dosimetry, the FS method was applied to EDR2 films (Carestream Health, Rochester, NY) for 6 MV photon beam from a linac (Elekta AB, Stockholm, Sweden) and small, circular radiosurgery cones (Elekta AB, Stockholm, Sweden) with diameters of 5, 7.5, 10, 12.5, and 15 mm. The ROFs for all these cones and central axis PDDs for 5, 10, and 15 mm diameter cones were determined at source‑to‑surface distance of 100 cm. The ROFs for small fields of CyberKnife system were determined using this technique with Gafchromic EBT3 film (Ashland, NJ, USA). The PDDs and ROFs were compared with ion chamber (IC) and Monte Carlo (MC) simulated values. The maximum percentage deviation of PDDFS with PDDIC for 4, 6, and 15 MV photon beams was within 1.9 %, 2.5 %, and 1.4 %, respectively, up to 20 cm depth. The maximum percentage deviation of PDDFS with PDDIC for electron beams was within 3 % for energy range studied of 8–15 MeV. The gamma passing rates of PDDFS with PDDIC were above 96.5 % with maximum gamma value of >2, occurring at the zero depths for 4, 6, and 15 MV photons. For electron beams, the gamma passing rates between PDDFS with PDDIC were above 97.7 % with a maximum gamma value of 0.9, 1.3, and 0.7 occurring at the zero depth for 8, 12, and 15 MeV. For small field of 5‑mm cone, the ROFFS was 0.665 ± 0.021 as compared to 0.674 by MC method. The maximum percentage deviation between PDDFS and PDDMC was 3 % for 5 mm and 10 mm and 2 % for 15 mm cones with 1D gamma passing rates, respectively, of 95.5 %, 96 %, and 98 %. For CyberKnife system, the ROFFS using EBT3 film and MC published values agrees within 0.2 % for for 5 mm cone. The authors have developed a novel and more accurate method for the relative dosimetry of photon and electron beams. This offers a unique method to determine PDD and ROF with a high spatial resolution in fields of steep dose gradient, especially in small fields.

9 illus, 2 tables, 31 ref

005111   BAI C, WU J, DENG X (Soochow Univ, People’s Republic of China) : A review of CMOS variable gain amplifiers and programmable gain amplifiers. IETE Tech Rev 2019, 36(5), 484-500.

CMOS implementations of variable gain amplifiers (VGAs) and programmable gain amplifiers (PGAs) are reviewed in this paper. They fall into two categories: Radio Frequency VGA/PGAs and Intermediate Frequency VGA/PGAs. Most approaches to realize gain tuning create linear VGAs and consequently exponential conversion are required. The CMOS circuit realizations of exponential converters are complex and are also reviewed. In contrast, PGAs benefit from their flexible gain control mode and hence have much simpler structures. However, lower distortions and higher gain accuracy can be achieved for PGAs. Therefore, PGAs are preferred in most scenarios. This paper also presents a CMOS Gilbert VGA and a novel high linearity constant bandwidth PGA with improved common mode rejection. The DC-offset cancellation methods are reviewed as well. Finally, trends of VGAs/PGAs in modern receivers are analysed.

31 illus, 1 table, 82 ref

005136   WANG Y, LIANG L, QI J, MO Y, WU M (Electronics Dep, Shandong Univ, Shandong Province, China) : Power system advanced scheduling based on advanced thermal rating. IETE J Res 2019, 65(5), 716-25.

The dynamic thermal rating (DTR) can improve the thermal load capacity of transmission lines. The integration of DTR into power system scheduling achieves full utilization of the line load capacity. Thus, this paper proposes the concept of advanced DTR and applies it to the advanced scheduling of power system. Based on advanced thermal rating, combining with conductor temperature, safe running time, and system power flow, the advanced scheduling is realized to achieve the predictive use of line thermal load capacity. In addition, based on the wind power forecast, the advanced scheduling in the wind turbine system is studied. The influence of the randomness of wind power on the advanced scheduling is presented. The results prove that the advanced scheduling based on advanced thermal rating can improve the economy and safety of power grid operation.

12 illus, 5 tables, 15 ref

005122   KARAMZADEH S, RAFIEI V, SAYGIN H (Istanbul Aydin Univ, Istanbul, Turkey) : Multi-functional six ports SIW microwave component for X-band applications. IETE J Res 2019, 65(5), 689-93.

A novel symmetric two layer six ports multi-functional microwave component was designed and presented in the present study. The proposed component consists of two 90-degree broadband double layer substrate integrated waveguide couplers and two T-shape power dividers. By exciting each port, the component could act as a -6 dB equal power divider, an unequal -3/-6 dB 90- degree coupler, as well as a -3 dB equal coupler. This component with mentioned conditions covers 23 % frequency bandwidth with maximum magnitude and phase error of §0.5 dB and §0.6 degree in all bandwidths, respectively.

5 illus, 2 tables, 10 ref

005125   KRISHNA LOK S (CSIR-National Aerospace Laboratories, Bengaluru, Email: kls@nal.res.in) : Multi-physics based modeling and simulation of an aircraft brake system. Everyman's Sci 2019, 54(3), 160-5.

There are various types of Brake systems, in this manuscript, the focus is on the disc brake with a hydraulically actuated brake system. Modeling and simulation of a disc brake system for a typical tricycle aircraft are being presented. The various input parameters that are essential for simulation, presented in a tabular form and discussed its significance. The emerging field of multi-physics based modeling and simulation explained with a model figure and with a plot, indicating the disc brake system performance.

2 illus, 1 table, 10 ref

005116   ELAYARAJA M, PUNITHAVATHY I K, JEYAKUMAR S J, JOTHIBAS M, MANOHARAN C (PG & Research Physics Dep, T.B.M.L. Coll, Porayar- 609 307, Email: profpunithaphysics@gmail.com) : Structural, optical and photocatalytic properties of PEG assisted CdO nanoparticles by Co-precipitation method. Asian J Chem 2019, 31(10), 2222-8.

A simple and modified chemical precipitation method is used for synthesis of different PEG assisted cadmium oxide nanoparticles. The prepared products were characterized by X-ray diffraction, Fourier transform infrared, ultraviolet, scanning electron microscopy and energy dispersive X-ray analysis. The XRD patterns revealed the cubic phases and calculated particle sizes are 36.42, 34.27, 33.54 and 35.21 nm for pure CdO with 2, 4 and 6 % PEG nanoparticles respectively, From these results, it can be observed that the average crystalline size decreases with increasing PEG concentration. The functional groups and band area of the product were established by FTIR spectroscopy. The band gap energy of CdO nanoparticles increased from 2.54 to 2.94 eV by increasing PEG concentration .The surface morphology and element composition have been confirmed form SEM with EDX analysis. In addition, the photocatalytic performance of PEG assisted CdO nanoparticles with methylene blue indicated that the CdO can be utilized a good photocatalyst for degradation of methylene blue.

8 illus, 2 tables, 25 ref

003900   KUMAR D, BHATTACHARYYA A S (Nano Science and Technology Dep, Central Univ of Jharkhand, Brambe- 835 205, Email: arnab.bhattacharya@cuj.ac.in) : Low energy ion beam study on Co/CoO thin films. Indian J Pure & Appl Phys 2019, 57(8), 605-6.

Computer simulation using SRIM software has been done for ion beam irradiation of different metal ions on Co/CoO thin film which is an FM/AFM system. The films have been experimentally deposited by magnetron sputtering and subjected to low energy ion beams (LEIB) of different energies and fluences. The variation of Si ion energy led to different ion distribution profiles which could be correlated with the morphological changes like dewetting occurring at the surface. Such phenomenon is potentially important for making spintronic devices in future.

3 illus, 4 ref

003887   DUTT S, SAXENA M, NAPIORKOWSKI P J, KUMAR R, ABRAHAHM T, ALLMOND J M, GWALIK A, HADYNSKA-KLEK K, HLEBOWICZ M, IWANICKI J, et al. (Physics Dep, Aligarh Muslim Univ, Aligarh- 202 001, Email: sunilduttamu@gmail.com) : Multi-step Coulomb excitation of ¹³²Ba at HIL, Warsaw. Indian J Pure & Appl Phys 2019, 57(8), 599-601.

To determine the shape of ¹³²Ba Coulomb excitation measurement has been performed at U-200P cyclotron at Heavy Ion Laboratory, University of Warsaw, Poland. A ³²S beam of ~90 MeV energy has been bombarded on enriched ¹³²Ba-target to Coulomb excite the latter nuclei. EAGLE gamma-ray spectrometer consisting of 15 single crystal HPGe detectors has been used to detect the deexcited gamma-rays from Coulomb excited Ba nuclei. The data has been collected using Particle-gamma coincidence technique for a period of seven days. The back scattered projectiles have been identified with 48 PiN diodes of 0.5 X 0.5 cm² active area mounted in a scattering chamber of ~5 cm radius called as ‘Munich chamber’. The energy states up to ~1127 keV energy have been populated in the interested ¹³²Ba isotope. The preliminary results of the data analysis are presented here.

4 illus, 12 ref

003922   RANCHI A R (Central Univ of Jharkhand, Ranchi- 835 205, Email: abhishekroy95quanta@gmail.com) : Quantum computational simulation to calculate the deuteron binding energy. Indian J Pure & Appl Phys 2019, 57(8), 596-8.

This paper in a nutshell, introduces quantum computational techniques used in nuclear physics to provide us with a new path forward in the exploration of many-body systems that are of central importance to nuclear physics, such as the deuteron (the simplest case of a many body system). The purpose of this paper is to bind QC algorithms with calculations based on complex nuclei, which unravel important details about the properties of matter, and formation of heavy elements. This research approaches towards low-energy nuclear many-body problems by simulating the lightest of complex nuclei, the deuteron, and by applying the VQE algorithm (quantum algorithm to find ground state energy) we generate binding energies of the deuteron accurate to a reasonable error. This research direction leads us to a better understanding of how quantum computation and information could be applied to a range of light nuclei, using QC hardware that is expected to be available during the immediate next few years. Another feature of this research is that it also explores the presently available quantum computers at IBM called the IBM Q-Experience (Q-X), which can be accessed remotely via the web and can serve to facilitate many quantum computational experiments. This research proves how useful a tool the IBM Q-X is to devise new quantum algorithms and test them for nuclear physics as well as other diverse fields of physics.

1 illus, 11 ref

003886   DEB N K, KALITA K (Physics Dep, Gauhati Univ, Guwahati- 781 014, Email: nd_globe@yahoo.co.in) : Theoretical aspect of the deformation effect on fusion cross-sections induced by heavy ion systems ^16,18O + ⁵⁸Ni and ¹¹²Sn. Indian J Pure & Appl Phys 2019, 57(8), 590-5.

Applying twelve different versions of nuclear potentials, the influence of static quadrupole and hexadecapole deformation of targets and its orientations on the fusion cross section have been studied. The barrier parameters for the reactions ¹⁶O + ⁵⁸Ni, ¹⁶O + ¹¹²Sn and ¹⁸O + ¹¹²Sn have been estimated from the variations of total interaction potential with the inter-nuclear separation which is then used to determine the fusion cross section for the systems through Wong’s formula. It has been found that the nucleus-nucleus potential strongly depends on the deformation parameters and orientation of the target. The experimental fusion cross-section of these reactions (wherever available) have been investigated by applying Wong’s formula along with the results of a one-dimensional barrier penetration model using coupled – channel (CCFULL) code. The fusion cross-sections by Prox 10, Prox 88, Prox 00, Prox 00 DP, CW 76, Ngô 80 and AW 95 potentials have been found out to be in better agreement towards the experimental data.

4 illus, 32 ref

003897   KAUR M, SINGH B B, PATRA S K (Physics Dep, Sri Guru Granth Sahib World Univ, Fatehgarh Sahib- 140 406, Email: manpreetphys@gmail.com) : Investigation of clustering effects and fragmentation in light mass nuclear systems formed in heavy ion reactions. Indian J Pure Appl Phys 2019, 57(8), 584-9.

The clustering effects in light mass alpha conjugate ²⁰Ne, ²⁸Si and non-alpha conjugate ²¹Ne, ²²Ne nuclear systems have been investigated comparatively, within the collective clusterization approach of dynamical cluster-decay model. The evolution of cluster structure with temperature at three different temperatures corresponding to ground state, Ikeda’s threshold energy and experimentally available energy has been made by taking into account the modified pairing strength in liquid drop energies. The results present that in addition to xα-type clusters (x is an integer) and xn-xα type clusters in alpha conjugate and non-alpha conjugate nuclear systems, respectively, np-xα type (n–neutron, p-proton) clusters are also preformed significantly at higher experimental excitation energy due to decreased pairing strength in liquid drop energies with rising temperature. Further, the fragmentation analysis has been undertaken at higher excitation energies to explore the reaction mechanism in the decay of different Z = 5, 6, 7 (or complementary Z = 3, 4, 5) fragments/clusters in reference to experimentally available Z-distribution data. The analysis depicts the presence of competing mechanisms of fusion-fission (FF) and deep inelastic orbiting (DIO) in the decay path, where the contribution of DIO cross-section σ_DIO has been evaluated empirically. The higher contribution of σ_DIO has been found for C-yield in all three ²⁰Ne^*, ²¹Ne^* and ²²Ne^* nuclear systems and the experimental verification is called for the same. The DCM calculated total cross-sections for different Z-fragments are in agreement with the experimental data.

4 illus, 26 ref

003929   SINGH D, LINDA S B, GIRI P K, MAHATO A, UTKARSH, SHROTRIYA P K, MISHRA A K, ANSARI M A (Physics Dep, Central Univ of Jharkhand, Ranchi- 835 205, Email: dsinghcuj@gmail.com) : Pre-equilibrium particle emission due to heavy and light ion interactions. Indian J Pure Appl Phys 2019, 57(8), 580-3.

To understand the mechanism of pre-equilibrium particle emission using light and heavy ion beams with different targets at energy above the Coulomb barrier, a study has been done. The cross-sections for twelve systems ⁴He + ⁵⁹Co, ⁴He +¹²⁴Sn, ⁴He + ¹⁶⁵Ho, ¹²C + ⁵⁹Co, ¹²C +¹²⁴Sn, ¹²C + ¹⁶⁵Ho, ¹⁶O + ⁵⁹Co, ¹⁶O + ¹²⁴Sn, ¹⁶O + ¹⁶⁵Ho, ¹⁹F + ⁵⁹Co, ¹⁹F + ¹²⁴Sn and ¹⁹F + ¹⁶⁵Ho have been calculated using the statistical model code ALICE-91. Significant pre-equilibrium particle emission contribution has been obtained for lighter systems at higher projectile energy. It has also been found that the pre-equilibrium particle emission affects predominantly over the equilibrated compound nucleus emissions at high projectile energies. Pre-equilibrium fraction (F_PEQ) has been deduced from the excitation function data for different systems at different projectile energies. The present results indicate that the probability of pre-equilibrium particle emission depends not only on a single entrance channel parameter, but it also depends on various entrance channel parameters, namely: projectile energy, mass of the projectile, mass of the target and entrance-channel mass asymmetry. The present analysis of the data also suggests that the pre-equilibrium particle emission contributes significantly at higher projectile energy for lighter mass projectile and target.

3 illus, 13 ref

003896   KAUR A, SHARMA M K (Thapar Institute of Engineering and Technology, Patiala- 147 004, Email: amanganday@gmail.com) : Fission fragmentation analysis of ²¹¹At* nucleus formed in ¹⁹F+¹⁹²Os reaction. Indian J Pure Appl Phys 2019, 57(8), 576-9.

The fission decay of ²¹¹At^* compound nucleus formed in ¹⁹F + ¹⁹²Os reaction has been studied using dynamical cluster-decay model (DCM) and the calculated fission cross-sections find nice agreement with the experimental data. The DCM - calculated preformation probability P₀ suggests the multimodal fission distribution of ²¹¹At^* nucleus which is systematically analyzed over a wide energy range (E_c.m = 75.7 MeV - 95.3 MeV). The behavior of fragment mass distribution shows that the contribution of asymmetric fragments is predominant across the Coulomb barrier. However, the contribution of symmetric component is relatively more at below barrier region. The range of fission fragments is identified for the decay of ²¹¹At^* compound nucleus, where ⁸⁵Br and its complementary fragment ¹²⁶Sn form the most preferred fission-pair, independent of incident energy. Finally, a comparison of peak ratio of the symmetric and asymmetric fission fragments is worked out as a function of incident energy for having better insight of fragmentation path in the fissioning channel. Beside this, the dependence of fission fragment mass distribution on angular momentum (l) is duly addressed at extreme centre-of-mass energies.

4 illus, 1 table, 15 ref

003881   ALI R, SINGH D, KUMAR H, TALI S A, ANSARI M A, RASHID M H (Physics Dep, G F (PG) College, Shahjahanpur- 242 001, Email: rahbara@gmail.com) : Signature of incomplete fusion reaction in ²⁰Ne + ¹⁵⁹Tb system: Entrance channel parameters effect. Indian J Pure Appl Phys 2019, 57(8), 570-5.

More complex and interesting phenomenon of incomplete fusion (ICF) reactions induced by ²⁰Ne on ¹⁵⁹Tb have been measured at several beam energies range of 4.3 - 8.2 MeV/A by using catcher foil technique followed by the gamma-ray spectrometry. The cumulative cross-sections of evaporation residues produced in above reaction have been measured and deduced independent cross-sections have been compared with statistical model based computer code PACE-2. The complete fusion (CF) channels pxn agrees well with PACE-2 predictions after the subtraction of precursor contribution. The alpha emission products show higher cross-section than that predicted by the complete fusion product, which is attributed to the presence of incomplete fusion of projectile with target at lower energies. This enhancement in the measured cross-section is attributed to the fact that these residues are formed not only by complete fusion but also through the ICF of ²⁰Ne into α clusters, i.e., ²⁰Ne into ¹⁶O+α and/or ¹²C+2α etc. For the better understanding of ICF, the incomplete fusion fraction has also been deduced and its sensitivity with various channel parameters like projectile energy, entrance channel mass-asymmetry, α-Q value, Coulomb effect (Z_PZ_T), deformation parameter (β₂) have been observed.

5 illus, 14 ref

003925   SAVADI V V, MAJEED I, SHUAIB M, SHARMA V R, YADAV A, SINGH D P, SINGH P P, UNNATI, SHARMA M K, KUMAR R, et al. (Physics Dep, Petroleum and Energy Studies Univ, Dehradun- 248 007, Email: dpsingh19@gmail.com) : Thin layer activation analysis of ¹⁶O induced reactions for surface wear studies in some natural isotopes. Indian J Pure Appl Phys 2019, 57(8), 566-9.

In the present work, the residual activity induced in ¹⁸¹Ta targets bombarded with ¹⁶O beam in the energy range ≈70-100 MeV have been measured. Stacked foil activation has been employed to measure the cross-sections of the several radio-isotopes populated through different nuclear reaction across various energies. Yields of the radio-isotopic products such as ^194,193,192Tl, ^193,192Hg, ^192,191,190Au have been obtained with the help of the characteristic γ-lines. Further, calibration curves are deduced by observing remnant activity induced across different depths in the target material. As a result an attempt has been made to employ thin layer activation technique with increased sensitivity for the study of surface wear.

2 illus, 1 table, 21 ref

003902   KUMAR S, GIRI P K, KUMAR R (Central Univ of Jharkhand, Ranchi- 835 205, Email: rakuiuac@gmail.com) : Fusion incompleteness in ¹⁴N + ¹⁶⁹Tm system: Measurement of recoil range distributions. Indian J Pure Appl Phys 2019, 57(8), 562-5.

To understand the incomplete fusion reaction dynamics and its dependency on various entrance channel parameters, an experiment using the forward recoil range technique was performed for the ¹⁴N + ¹⁶⁹Tm system at projectile energy ≈ 83 MeV. The recoil-catcher activation technique followed by off-line γ-spectrometry was employed. Experimentally measured forward recoil range distributions of evaporation residues indicates the occurence of incomplete fusion channels in addition to complete fusion. Full and partial linear momentum transfer components have been observed. The experimentally measured ranges of the evaporation residues formed due to the transfer of complete and/or partial momentum by projectile in the thin Al catchers were compared with the SRIM code. The observed incomplete fusion events can be explained on the basis of the breakup of the projectile viz. ¹⁴N → ⁸Be and/or ⁴He, where ⁸Be and/or ⁴He fuses with ¹⁶⁹Tm target and transfers the partial linear momentum to the target nucleus. The present data clearly indicates that the evaporation residues were not only populated through complete fusion, but incomplete fusion also plays an important role at low projectile energy.

2 illus, 12 ref

003907   MAHATO A, SINGH D, GIRI P K, LINDA S B, KUMAR H, TALI S A, ANSARI M A, KUMAR R, MURALITHAR S, SINGH R P (Physics Dep, Central Univ of Jharkhand, Ranchi- 835 205, Email: dsinghcuj@gmail.com) : Measurement of excitation functions in ¹⁴N- ion induced reactions. Indian J Pure Appl Phys 2019, 57(8), 557-61.

Excitation functions of nine evaporation residues populated through complete and/or incomplete fusion in ¹⁴N + ¹²⁴Sn system in the projectile energy range ≈4−7 MeV/nucleon have been measured. Recoil catcher activation technique using offline γ -ray spectrometry has been employed in these measurements. The evaporation residues produced through xn and pxn channels are found to be well reproduced by the theoretical predictions of PACE-4. In case of evaporation residues produced through α-emitting channels, significant enhancement in the measured excitation functions over their theoretical predictions has been observed. This enhancement indicates that these α-emitting channels are attributed to the incomplete fusion process. The comparison of present study with literature data also shows that the ICF probability depends on various entrance channel parameters. A new combined parameter  has been found to explain more precisely the ICF dynamics than other entrance channel parameters.

4 illus, 31 ref

003888   GIRI P K, SINGH D, LINDA S B, MAHATO A, KUMAR H, TALI S A, ANSARI M A, KUMAR R, SINGH R P, MURALITHAR S (Physics Dep, Central Univ of Jharkhand, Ranchi- 835 205, Email: dsinghcuj@gmail.com) : Dependency of incomplete fusion on target deformation. Indian J Pure Appl Phys 2019, 57(8), 552-6.

Excitation functions for the evaporation residues ^161,159,158Er (xn), ^161-159Ho (pxn), ^157,155Dy (αxn) and ¹⁵⁵Tb (αpxn) populated via complete and/or incomplete fusion in system ¹⁶O + ¹⁴⁸Nd system at low projectile energies ≈3−7 MeV/A have been measured. In these measurements recoil catcher activation technique followed by offline γ -ray spectrometry has been used. The total measured excitation functions of the evaporation residues ^161,159,158Er (xn) and ^161-159Ho (pxn) produced through xn and pxn channels are found to be well reproduced with the total PACE-4 predictions after subtraction of precursor contributions. A significant enhancement in the total measured excitation functions over their total theoretical predictions for the evaporation residues ^157,155Dy (αxn) and ¹⁵⁵Tb (αpxn) produced in α-emitting channels has been observed. This enhancement is attributed due to the presence of break-up of the incident projectile ¹⁶O into α clusters (i.e., break-up of ¹⁶O into ¹²C + α) and incomplete fusion of projectile ¹⁶O with target ¹⁴⁸Nd at these low energies. A comparison of the present data with earlier measurements indicates that the ICF probability depends on Coulomb factor (Z_PZ_T) along with target deformation (). However, more systematic study on same Z spherical and deformed targets with same projectile at low energy is required to understand the role of target deformation on incomplete fusion dynamics.

5 illus, 32 ref

003904   LINDA S B, GIRI P K, SINGH D, MAHATO A, KUMAR H, TALI S A, ANSARI M A, KUMAR R, MURALITHAR S, SINGH R P (Physics Dep, Central Univ of Jharkhand, Ranchi- 835 205, Email: dsinghcuj@gmail.com) : Study of incomplete fusion dynamics on various entrance channel parameters. Indian J Pure Appl Phys 2019, 57(8), 548-51.

The present work has been carried out to understand the dynamics of incomplete fusion reactions and its dependency on various entrance channel parameters at low projectile energy. The excitation functions of evaporation residues ^137,135,133Ce (xn), ¹³³La (pxn), ^{133m,131m,129}Ba (αxn), ^135m,132Cs (αpxn), ^131mXe (2αxn) and ¹³¹I (2αpxn) have been measured for the system ¹⁶O + ¹²⁴Sn at projectile energy ≈3-7 MeV/nucleon. The analysis of measured excitation functions have been done within the framework of statistical model code PACE-4. The incomplete fusion fraction (F_ICF) has been deduced from present measurements for the study of systematics. Two new combined parameters  and  have been introduced as a combination of the entrance channel parameters mass-asymmetry (), coulomb factor (Z_PZ_T) and deformation parameter (β₂) of target. The present study shows that incomplete fusion fraction decreases indepndently for diffrent projectiles with increase in these parameters. These combined parameters can explain the characteristics of incomplete fusion dynamics more clearly as compared to individual entrance channel parameters at these energies. These present results suggest that the incomplete fusion dynamics can be better explained by combined effects of entrance channel parameters than that of their individual effects.

4 illus, 36 ref

003936   TALI S A, KUMAR H, ANSARI M A, ALI A, SINGH D, ALI R, GIRI P K, LINDA S B, KUMAR R, PARASHARI S, et al. (Physics Dep, Aligarh Muslim Univ, Aligarh- 202 002, Email: amusuhailtali@gmail.com) : Role of alpha cluster over non alpha cluster projectile in low energy incomplete fusion reaction dynamics. Indian J Pure Appl Phys 2019, 57(8), 544-7.

Continuous efforts are being made to comprehend the process of low energy incomplete fusion (ICF) reaction dynamics. The lack of proper theoretical model below 8 MeV/nucleon, which could reproduce the experimentally measured ICF data satisfactorily, makes it the topic of great interest. Another important motivation is to look for some systematic dependence of ICF on various entrance channel parameters. Keeping the aforementioned aspects into consideration, the experiment has been performed using ¹²C ion beam on ¹⁶⁵Ho target by employing the stacked foil activation technique. The experimentally measured cross sections of the populated evaporation residues have been measured and compared with the complete fusion code PACE4. It has been observed that the measured cross sections for evaporation residues populated via xn and pxn emission channels are well reproduced by PACE4 code. However, in the α-emission channels (observed in the projectile break-up), the significant enhancement in the measured cross sections over PACE4 predictions is observed which is accredited to ICF process. In the present work, ICF dependence on the target deformation and the combined parameter µ _* Z_PZ_T * (1-β₂) has been studied. The ICF fraction has also been found sensitive to projectile Q_α- value.

4 illus, 18 ref

003901   KUMAR H, TALI S A, ANSARI M A, ALI R, SINGH D, NASEEF M P N, KUMAR R, GOLDA K S, SINGH R P, MURALITHAR S (Physics Dep, Aligarh Muslim Univ, Aligarh- 202 002, Email: amu.harish@gmail.com) : Study of break-up fusion process from forward recoil range distribution measurement. Indian J Pure Appl Phys 2019, 57(8), 540-3.

In the present work, the break-up fusion or incomplete fusion (ICF) process has been studied from the forward recoil range distribution measurement for ¹⁶O + ¹⁷⁵Lu system at ≈ 96 MeV energy. The measured forward recoil range distributions are analyzed in the framework of code SRIM. The present analysis shows clearly the role of linear momentum transfer and also the break-up of projectile ¹⁶O into its fragments (¹²C + ⁴He and/or ⁸Be + ⁸Be). Any systematic trend is not observed with the target deformation parameter (β₂) dependent study of ICF. It is observed that projectile structure also affects the ICF dynamics. The projectile α-Q-value is found to be a suitable parameter which explains effectively the observed projectile structure effect on ICF.

3 illus, 20 ref

003912   NILAKANTHAN V K, VANAMALI C S, RAGHAVENDRA S, KUMMAR K B V (Studies in Physics Dep, Mangalore Univ, Mangalagangothri- 574 199, Email: nveluthat@gmail.com) : Investigation of nucleon–nucleon interaction with confined one gluon exchange potential and one pion exchange potential. Indian J Pure Appl Phys 2019, 57(8), 536-9.

The nucleon-nucleon (N-N) interaction in the singlet (¹S₀) and triplet (³S₁) channels have been studied in the framework of relativistic harmonic model (RHM) using the resonating group method (RGM) in born-oppenheimer approximation. The full hamiltonian consists of the kinetic energy, two body confinement potential, confined one gluon exchange potential (COGEP) and one pion exchange potential (OPEP). Contribution of COGEP and OPEP to the adiabatic N-N interaction potential has been discussed. The presence of short range repulsion for the N-N interaction has also been investigated and the reason for the same has been attributed to the presence of color magnetic terms in the COGEP.

4 illus, 1 table, 27 ref

003879   AGOTIYA V K, NILIMA I (Physics Dep, Central Univ of Jharkhand, Ranchi- 835 205, Email: agotiya81@gmail.com) : On the fate of quarkonia in quark gluon plasma medium within a quasi-particle model. Indian J Pure Appl Phys 2019, 57(8), 531-5.

We work on equations of state for hot QCD obtained from a hard thermal loop expression for the gluon self-energy, by employing the quasi-parton equilibrium distribution functions. The method involves mapping the interaction part of the equation of state to an effective fugacity of otherwise non-interacting quasi-gluons. Using the quasi-gluon distribution function, we have studied the dissociation of heavy Quarkonium in hot QCD medium by investigating the medium modification to a heavy quark potential. Employing the in-medium (corrected) potential while considering the anisotropy (both oblate and prolate cases) in the medium, the thermal widths and the binding energies of the heavy quarkonia states (s-wave charmonia and s-wave bottomonia specifically, for radial quantum numbers n=1 and 2) have been determined. In the present article, we shall consider an anisotropic QGP medium which is described in terms of quasi-particle degree of freedom based on a recent proposed quasi-particle model for hot QCD equation of state. The presence of anisotropy makes the real-part of the potential stronger but the imaginary-part is weakened slightly. However, since the medium corrections to the imaginary-part is a small perturbation to the vacuum part, overall the anisotropy makes the dissociation temperatures higher, compared to isotropic medium.

2 illus, 1 table, 17 ref

003920   QUDDUS A, PATRA S K (Homi Bhabha National Institute, Anushakti Nagar, Mumbai - 400 085, Email: patra@iopb.res.in) : Effective surface properties of Sn isotopes. Indian J Pure Appl Phys 2019, 57(8), 527-30.

We have studied the effective surface properties such as  symmetry energy coefficient, pressure, and curvature coefficient of Sn isotopic series within the effective field theory motivated relativistic meanfield formalism (E-RMF)¹. The densities of the nuclei, calculated within E-RMF, are used as the inputs to the coherent density fluctuation model (CDFM)². We have used the recently predicted force parameter IOPB-I¹ and compared the results with the calculated values of widely accepted and well-known NL3 parameter set³. The small kinks, observed in the graph correspond to the magic numberin the isotopic series.

5 illus, 9 ref

003914   PANDIT V S (Variable Energy Cyclotron Centre, Kolkata- 700 064, Email: vspandit12@gmail.com) : Cyclotrons: Past, present and future. Indian J Pure & Appl Phys 2019, 57(8), 519-26.

New design and developments in the field of cyclotrons have shown that cyclotrons can well be tailored to suit a large variety of applications in different fields. Today cyclotrons are providing variety of light and heavy ion beams with energy ranging from few MeV to several hundreds of MeV for scientific experiments as well as for medical and industrial applications. The development of a 250 - 400 MeV/A cyclotron with proton and carbon beams has brought this advanced technique into hospitals for cancer therapy. Several proposals to generate about 10 MW of beam power using cyclotrons for energy generation or transmutation of nuclear waste are under active considerations. A brief summary of the cyclotron principle and an overview of different types of cyclotrons have been presented.

9 illus, 18 ref

003885   BOUZEKRAOUI Y, BENTAYEB F, ASMI H, BONUTTI F (Physics Dep, Mohammed V Univ, Morocco, Email: youssef0fsr@gmail.com) : Comparison of image quality of different radionuclides Technetium-99 m, Samarium-153, and Iodine-123. Indian J Nucl Med 2019, 34(3), 201-4.

The choice of the radionuclide has a key role in nuclear medicine which appearing the lowest scatter fraction. In addition, the presence of penetrated and scattered photons from collimator in single‑photon emission computed tomography images degrades resolution and contrast. Thus, image quality depends on sensitivity and resolution of the collimator–detector system. The goal of this study was to compare the image quality that can be achieved by three radionuclides: technetium‑99 m (Tc‑99 m), iodine‑123 (I‑123), and samarium‑153 (Sm‑153).  Tc‑99 m and Sm‑153 were imaged with low‑energy high resolution (LEHR) collimator, while I‑123 was imaged with medium‑energy (ME) collimator. We modeled the Siemens Symbia Medical system using Monte Carlo simulation code SIMIND. The imaging characteristics of each radionuclide were investigated by simulated data: point spread function, sensitivity (Cps/MBq) and geometric, penetration and scattering distribution. Tc‑99 m and Sm‑153 give best and results with LEHR collimator for spatial resolution (full width at half maximum [FWHM] = 3.19 mm; full width at tenth maximum [FWTM] = 6.73 mm) and (FWHM = 3.22 mm; FWTM = 7.39 mm), respectively. Whereas, I‑123 provided with ME collimator a lower resolution (FWHM = 4.89 mm; FWTM = 9.89 mm). The sensitivity recorded by Tc‑99 m, Sm‑153, and I‑153 were (31.21 Cps/MBq), (10.16 Cps/MBq), and (51.22 Cps/MBq), respectively. Tc‑99 m and Sm‑153 give the best and generally similar imaging properties with LEHR. For I‑123, the ME collimator helps lowering the influence of high‑energy gamma rays.

4 illus, 4 tables, 18 ref

003934   SYLA N, ELEZAJ N, ALIAJ F, TOLAJ Z, ZEQIRAJ A (Physics Dep, Prishtina Univ, Prishtina- 100 00, Kosovo, Email: njomza.elezaj@uni-pr.edu) : Finite element modeling of 31CrMoV9 steel hardness curves after gas nitriding. Indian J Chem Technol 2019, 26(4), 358-61.

This is a numerical and experimental study of the hardness curves in the precipitation layer of gaseous nitrided 31CrMoV9 alloy steel. Hardness has been measured with an automatic micro-hardness meter according to the Vickers method. It is known that gas nitriding as a diffusion process can be described by the differential equation known as Fick’s second law. This equation is solved with the Finite Element (FE) method. Modeling is based on the Orowan strengthening theory and the classic Johnson-Mehl-Avrami theory of precipitation. The model is constructed in the ANSYS application in the temperature field and experimental results are compared with theory (the model). The results prove that diffusion processes like nitriding can be modeled with FE methods.

1 illus, 16 ref

003882   ARISTIDE H C, COMLAN F J-L, BERTRAND G V, ARMAND D, MALAHIMI A, ANTOINE V (UNSTIM Multidisciplinary Research Laboratory of Technical Education, Lokossa, Benin, Email: hounaris@yahoo.fr) : Assessment of the thermal conductivity of local building materials using Lee’s disc and hot strip devices. Asian J Adv Basic Sci 2019, 7(2), 5-13.

The thermal conductivity of building materials is an important property for engineering and for the analysis of insulating materials. In this work, the thermal conductivity of Kosso and mahogany wood were determined following the device of Lee's disk. The results were then compared with those obtained by the hot strip device. In this line, Lee's disk device was designed and validated experimentally. According to the analysis of the data from the two wood species tested, the thermal conductivity of Kosso (measurement in the open air with a moisture content of 13 %) and mahogany wood (dry) obtained by the method of Lee drive, respectively, are (0.128 ± 0.005) W.m^-1 K^-1  and (0.120 ± 0.009) W.m^-1 K^-1  against respectively, (0,123 ± 0,001) m^-1  K^-1 and (0.134± 0,004) m^-1 K^-1 , obtained by the hot tape method. These results experimentally determined by the disk of Lee method are in good agreement with those obtained by the method of hot strip device. The calculation of the uncertainty of thermal conductivity was also done in this work.

18 illus, 5 tables, 14 ref

003883   ASHOK K, MASIN B, SREEMOOLANADHAN H, MATHEW M (Vikram Sarabhai Space Centre, Thiruvananthapuram– 695 022, Email: ashok@vssc.gov.in) : Effect of SN on magnetic and dielectric properties of Ni-Co spinel ferrite over LF and MF range. Trans Indian Ceram Soc 2019, 78(3), 131-6.

Nickel-cobalt ferrite (NCF) without Sn-dopant and with (x = 0 to 0.1%), (Ni_0.7Co_0.3)(Fe_2–xSn_x )O_4+d, have been synthesized through solid-state route. Calcination of oxides at 900 ^oC yielded spinel phase as confirmed by X-ray diffraction. Sn doping does not show much variation in lattice constants, but slightly increases crystallite size. Green compacts have been well sintered in 1150^o -1200 ^oC for 10 h. Microstructure of fractured specimens obtained using field emission scanning electron microscope show well packed polygonal grains with 2-3 $\mu$m size range. Dielectric and magnetic behavior of pristine and Sn-doped NCF have been measured in 100 Hz to 1 MHz range using a precision LCR meter, Sn-doping up to x=0.1 improves the dielectric properties of NCF, but deteriorates the magnetic properties.

10 illus, 1 table, 35 ref

003891   HUSSAIN I, BARIMAH E K, IQBAL Y, JOSE G, MUHAMMAD R (Physics Dep, Abdul Wali Khan Univ, KP- 23200, Email: raz@awkum.edu.pk) : Thermal, mechanical and optical properties of TiO₂ -doped sodium silicate glass-ceramics. Trans Indian Ceram Soc 2019, 78(3), 125-30.

In this study, local mineral (silica sand) obtained from Hazara division, Khyber Pakhtunkhwa, Pakistan was fabricated into soda-lime silicate glass. Titanium dioxide (TiO₂ ) concentration in the range of 1-3 wt% was added as a nucleating agent to investigate its effect on crystallization phase, density, hardness, thermal expansion coefficient ($\mathrm{\alpha }$), glass transition temperature (Tg ), micro hardness and optical bandgap of soda-lime silicate glass. XRD analysis revealed the formation of different crystalline phases such as cristobalite (SiO₂ ), wollastonite (CaSiO₂ ), and rutile (unrefined TiO₂ , often with iron, F³⁺) at different processing temperatures. The coefficient of thermal expansion and the optical gap energies varied from 72.5$\times$10^–7/K to 77$\times$10^–7/K and 3.71-3.93 eV with TiO₂ concentration, respectively. The mechanical properties were also in good agreement with those of commercially used glass-ceramics.

6 illus, 2 tables, 38 ref

003913   OLADIPO O A, ADENIYI J O, ADIMULA I A, OLAWEPO A O, OLOWOOKERE A, SALIFU F U, RADICELLA S M, REINISCH B W (Physics Dep, Ilorin Univ, Ilorin, Nigeria, Email: ooladipo@unilorin.edu.ng) : The role of the F-region vertical drift on the onset time of the equatorial spread F over Ilorin, Nigeria. J Earth Syst Sci 2019, 128(5), 135.

The equatorial ionosphere often shows the occurrence of plasma-density irregularities and velocity fluctuations with a broad range of scale sizes and amplitudes. These irregularities in the F-region are commonly referred to as the equatorial spread F (ESF) and they are predominantly a night-time phenomenon. The vertical drift of ionisation to higher altitudes post-sunset hours has been suggested to be responsible for the occurrence of these irregularities. We have therefore used all the available ionograms at Ilorin, Nigeria (latitude = 8.48 ^∘N, longitude= 4.67 ^∘W and dip= 4.1 ^∘S) to study the occurrence of ESF and the effect of the F-region drift on the occurrence of ESF. The available data at Ilorin, though not continuous, cover a period of 6 yrs (i.e., 2002, 2005, 2006, 2007, 2008 and 2010). The F-region vertical drift velocity was estimated starting from around local sunset until the onset of ESF, and the maximum value for a night (V_Z,max) is used to represent the strength of the E×BE×B drift for that night. Results obtained showed that the percentage occurrence of ESF increases with the increase in solar activities. A seasonal trend is also observed in the occurrence frequency; occurrence seems to be more frequent during and around the equinox periods. The onset time or the time of commencement (TOC) of ESF was observed to vary from day to day. Also, V_Z,max seems to increase with the increase in solar activities, which in turn influences the TOC of ESF. It was found that the higher the V_Z,max, the closer the TOC was found to be to the local time V_Z,max. In a few cases, there was no noticeable movement of ionisation prior to the commencement of the ESF, and this might be pointing to the fact that the drifting of ionisation to a higher altitude is not the only condition for the occurrence of ESF. Other conditions that have been identified to play a role in ESF occurrence are thermospheric neutral dynamics, equatorial thermodynamic meridional winds and the post-sunset base height of the F-layer (h′F).

10 illus, 1 table, 31 ref

003933   SULTANA J, BHATTACHARYA A, KARMAKAR A, DALAPATI G K, CHATTOPADHYAY S (Electronic Science Dep, Calcutta Univ, Kolkata- 700 009, Email: scelc@caluniv.ac.in) : Graphene-nanoparticle incorporated responsivity tuning of p-CuO/n-Si-based heterojunction photodetectors. Bull Mater Sci 2019, 42(4), 194.

The current work focusses on investigating the appropriate wt % of graphene-nanoparticles to be incorporated into the CuO film as a dopant for enhancing its optoelectronic properties. CuO and graphene-nanoparticle-incorporated CuO films (CG) are grown by employing a chemical bath deposition (CBD) method. Graphene-nanoparticles have been incorporated at different wt % (1, 5 and 10 %) with respect to the metal salt (CuCl₂·2H₂O), and a comparative study has been performed on the systematic change of the film morphology, chemical composition, oxidation states, crystallite structures and photo-sensing effects. It has been found that the morphology and the structural properties of CBD grown CuO films have been tuned by the incorporation of graphene-nanoparticles. The results show a significant enhancement in the optoelectronic properties of CG1 (1 %) and CG5 (5 %) films. The optical properties of the as-grown films have been observed to be modified by graphene-nanoparticle incorporation. Moreover, the electronic and optoelectronic characteristics of the fabricated p-CuO/n-Si heterojunctions have also been investigated. The enhancement of the optoelectronic properties of the CG5 sample as compared to other grown films in the present study suggests that the responsivity and photodetecting properties of the CBD grown CuO films can be improved by graphene-nanoparticle incorporation.

13 illus, 2 tables, 36 ref