000144   RONG J H, ZHANG L, YUN G H, BAO L B (Inner Mongolia Univ, Hohhot- 010 021, China, Email: jhrong502@163.com) : The angular dependence of ferromagnetic resonance in exchange coupling bilayer films with stress anisotropy. Indian J Phys 2019, 93(2), 207–11.

In this work, the ferromagnetic resonance modes are worked out considering in-plane anisotropy and out-ofplane anisotropy, respectively, in ferromagnetic/antiferromagnetic bilayer films. The ferromagnetic resonance frequency, magnetic susceptibility, and field linewidth with stress anisotropy have been investigated by using ferromagnetic resonance method. The results show that while applied magnetic field is applied along some directions, the ferromagnetic resonance frequency can be enhanced and field linewidth can be broaden by increasing the intensity of stress anisotropy field. Furthermore, the effect of stress anisotropy field proves substantially stronger for out-of-plane anisotropy than in-plane anisotropy.

7 illus, 30 ref

000130   JOHN B, SILVENA G G, HUSSAIN S, KUMAR M C S, RAJESH A L (Physics Dep, St. Joseph’s Coll (Autonomous), Tiruchirappalli - 620 002, Email: aleorajesh@gmail.com) : Surfactant-mediated solvothermal synthesis of CuSbS₂ nanoparticles as p-type absorber material. Indian J Phys 2019, 93(2), 185–95.

The novel chalcostibite CuSbS₂ had gained unique attention due to their dynamic nature as less toxic, costeffective and earth abundant materials for the synthesis of an absorber layer in solar cell application. Herein, a facile and effective solvothermal method was used to enhance the sphere-like grain growth in the presence of polyvinylpyrrolidone (PVP) along with other precursor’s, followed by the deposition of CuSbS₂ thin films using drop casting method. The synthesized nanoparticles and the deposited films were characterized for their structural, morphological, optical and electrical properties using different characterization techniques. X-ray diffraction (XRD) and Raman analysis revealed that as the amount of PVP increased, the crystallinity improved and the impurity phase formation reduced. High-resolution transmission electron microscope (HRTEM) with reduced crystallite size in the range of 2–5 nm and field emission scanning electron microscope (FESEM), exhibited sphere-shaped grains indicating the effect of PVP as surfactant for the growth of CuSbS₂ nanomaterials. The average elemental composition of the nanoparticles had been determined using EDX analysis, and the result yielded Cu rich in all the samples. Optical studies using UV–Vis-NIR diffuse reflectance spectroscopy revealed that obtained CuSbS₂ nanoparticles were having the absorption in the entire visible region and the direct band gap energy was in the range of 1.25 eV to 1.53 eV and that of photoluminescence spectrum gave the emission in the near IR region. The hall measurement studies showed that the deposited CuSbS₂ films exhibited p-type conductivity. Devices were fabricated with the configuration of FTO/n-TiO₂/p-CuSbS₂/Ag, and the electrical properties were studied by recording the current- voltage (I-V) characteristics of the heterojunction device structures.

8 illus, 2 tables, 48 ref

000129   ISMAIL A M, MOHAMMED M I, EL-METWALLY E G (Physics Dep, Ain Shams Univ, Cairo- 11757, Egypt, Email: dr.ahmedm.ismail@gmail.com) : Influence of gamma irradiation on the structural and optical characteristics of Li ion-doped PVA/PVP solid polymer electrolytes. Indian J Phys 2019, 93(2), 175–83.

Lithium ions-doped polyvinyl alcohol/polyvinyl pyrrolidone (PVA/PVP) films were prepared by solution casting technique and exposed to 100 kGy gamma radiation. The structural modifications in the samples before and after irradiation were studied using X-ray diffraction XRD and UV–Vis spectroscopy. The results indicated that absorbance A ($\mathrm{\lambda }$) and absorption index (k) increased, while semicrystalline nature of the blend decreased due to the addition of Li₂SO₄ and irradiation. The optical band gap E^opt_g of the composites showed significant decrease from 2.98 to 2.196 eV by adding Li₂SO₄ and from 2.83 to 2.08 eV after irradiation due to cross-linking. The Tauc’s relation indicated that allowed transitions are indirect for both irradiated and unirradiated samples. The Urbach energy (E_u) increased with increasing Li ion content and exposure to $\gamma$ irradiation. The dependence of dielectric permittivity $\epsilon$₁, dielectric loss $\epsilon$₂ and optical conductivity $\sigma$_opt on photon energy hν was also studied.

12 illus, 2 tables, 38 ref

000110   ANGADI V J, MATTEPPANAVAR S, MARAMU N, KUMAR P M, PASHA U M, DEEPTHI P R, PRAVEENA K (Presidency Univ, Bengaluru - 560 064, Email: jagadeeshaangadi@presidencyuniversity.in) : Reduced A–B super exchange interaction in Sm³⁺–Gd³⁺-doped Mn–Zn ferrites due to high energy gamma irradiation. Indian J Phys 2019, 93(2), 169–74.

We report the effect of gamma irradiation on structural and magnetic properties of Mn²⁺_0:4Zn²⁺_0:6Sm³⁺_x Gd³⁺_y Fe³⁺_2-(x+y) O₄ (where x = y = 0.01, 0.02, 0.03, 0.04 and 0.05) ceramics prepared by self-propagating high-temperature synthesis method using glucose and urea as fuels. The synthesized samples are characterized through X-ray diffractometer (XRD) and vibration sample magnetometer at room temperature before and after gamma irradiation. The XRD patterns of before irradiation samples reveal the formation of polycrystalline, mixed spinel cubic structure. The mixed (impurity) phases are identified as Fe₂O₃, SmFeO₃ and GdFeO₃, and the amount of these residual phases is comparatively less after gamma irradiation. Lattice parameter is found to be increasing with increasing Sm³⁺ and Gd³⁺ concentration is observed after gamma irradiation. This is due to the irradiation of ionizing gamma radiation with the material which gives rise to the production of lattice defect and then the displacing of atoms from their equilibrium position. The magnetic properties reveal that saturation magnetization (M_s), remnant (M_r), remnant ration (M_r/M_s), coercivity (H_c), magneton number (n_B), anisotropy constant (K) have been decreasing with increasing Sm³⁺ and Gd³⁺ concentration before and after gamma irradiation. This is due to breaking of ferrimagnetic ordering, surface state pinning and cation inversion of the materials. Hence, our results propose the good radiation stability of the samples when compared to reported material stability in the literature.

6 illus, 2 tables, 33 ref

000146   SHARMA N, HOODA M, SHARMA S K (Space Dep, Semi-Conductor Laboratory, Chandigarh, Email: nagksharma@rediffmail.com) : Stresses in thin films: An experimental study. Indian J Phys 2019, 93(2), 159–67.

Thin film technology is a relatively young and ever-growing field in the physical and chemical sciences, which is confluence of materials science, surface science, applied physics and applied chemistry. Thin film technology has its objectives in the provision for scientific bases for the methods and materials used in thin film electronics (integrated circuits and micro-electro-mechanical system). Additionally, it provides a sufficient data in the area of applications to permit for understanding of those aspects of the subject that might still be termed an ‘‘art’’. Thin films of metals were probably first prepared in asystematic manner by Michael Faraday, using electrochemical methods. Thin films go through several distinct stages during growth, each affecting the resulting film microstructure and internal stress. Hence before proceeding to synthesis and characterization, the knowledge of formation, growth and stress generation in thin film is necessary. This paper explains the influence of process parameters on stress in silicon nitride (Si₃N₄) thin films with experimental results.

12 illus, 25 ref

000128   HEBBAR V, RAVIKUMAR H B, NANDIMATH M, MASTI S, MUNIRATHNAMMA L M, NAIK J, BHAJANTRI R F (Physics Dep, Karnatak Univ, Karnataka - 580 003, Email: rfbhajantri@gmail.com) : Conductivity and free volume studies on bismuth sulfide/ PVA: Polypyrrole nanocomposites. Indian J Phys 2019, 93(2), 147–58.

The polymer composite films of polyvinylalcohol:polypyrrole blend containing different wt % of bismuth sulfide (Bi₂S₃) particles are prepared through in situ oxidation followed by solution casting method, where the particles are coated with blend matrix. The XRD studies affirm the enhanced crystallinity of the composites. The variation of crystallite size is measured with the Debye–Scherrer method. The DSC studies are used to investigate the glass transition that occurred in the Bi₂S₃ particles-filled polymer blend matrix. The AFM and SEM studies illustrated the effect of insertion of metallic sulfide particles on the surface morphology. The addition of bismuth sulfide particles results in the increased mechanical properties of the composite matrix. The electrical conductivity is determined by the Cole–Cole plot fitted using equivalent circuit model, and the conductivity is observed to be enhanced with an increase in filler content due to the enhanced conductive pathways. The variation of o-Ps lifetime, o-Ps intensity, average size of the free volume and fraction of free volume is studied using Tao–Eldrup Model. The obtained free volume parameters are correlated with the electrical, microstructural and thermal properties. The increased interfacial width is illustrated in terms of increased free volume size. The enhanced free volume provides more space for mobility of charge carriers, and hence the conductivity is enhanced.

8 illus, 5 tables, 42 ref

000117   CHATTI S, GHABI C, MHIMID A (Monastir Univ, Monastir-5019, Tunisia, Email: chatti_saida@yahoo.com) : The effect of obstacles’ characteristics on heat transfer and fluid flow in a porous channel. Indian J Phys 2019, 93(1), 123–38.

The fluid flow and heat transfer around obstacles are an engineering and research interest. This paper dealt with this matter in a porous channel. It explained the features of the presence of hot solid obstacles in porous media. These obstacles were located at different positions inside the medium. The particularity of this work is coupling two complex phenomena: the heat transfer in porous media and the presence of hot solid obstacles. This is the first time that these phenomenona were studied. The diffusion–convection equation is adopted to calculate the temperature. The viscous heat dissipation and compression work due to the pressure were not taken into consideration. This choice and assumptions were based on our previous work. The numerical simulation was done using the generalized lattice Boltzmann method. To ensure that our numerical code is free of errors, we resorted to benchmark cases. Then, we were interested in the effect of triangular and rectangular obstacles on the heat transfer and fluid flow in a porous channel. The isotherms and the velocity contours were studied for several dynamic parameters. The fluid behavior was described by the streamlines and the velocity fields. The velocity profile was followed along the porous channel. These results allow concluding that the Reynolds number increment led to the increase in the heat transfer and the fluid velocity. The increment of the distance between the inlet and the obstacle generates the same conclusion.

11 illus, 2 tables, 29 ref

000118   CHEN R, PAN L, NIE L, CHEN C, ZENG C, LIU S (Kunming Univ of Science and Technology, Kunming- 650 093, China, Email: linrunie@126.com) : Harmonic velocity noise and its resonance in classical systems. Indian J Phys 2019, 93(1), 115–21.

We investigate a harmonic velocity noise and its resonance effect in classical linear and bistable systems. The harmonic velocity noise can be obtained via RLC oscillation circuit driven by the classical Gaussian white noise. Our numerical results indicate that mean square displacement of a free Brownian particle under action of the noise tends to be zero. In the classical systems, the noise not only suppresses fluctuation of particle but also induces resonance effect. Moreover, a noise-enhanced stability phenomenon in the bistable system is also found.

8 illus, 44 ref

000115   BORGOHAIN D R, SAHARIA K (Physics Dep, North Eastern Regional Institute of Science and Technology, Arunachal Pradesh - 791 109, Email: ksaharia@rediffmail.com) : Sheath criterion in constant mean free path collisional plasma with two distinct temperature q-nonextensive electrons. Indian J Phys 2019, 93(1), 107–14.

A constant mean free path collisional plasma sheath model is investigated in the presence of two-temperature qnonextensive electrons and fluid ions. By using Sagdeev potential technique, a modified Bohm sheath criterion is derived and also verified. It is shown that the density distribution of positive ions reduces monotonically when the Bohm velocity lies between the derived limits. The effect of collision on the plasma sheath profiles viz. density, potential, net space charge density and positive ion velocity in the sheath in presence of the proposed plasma configuration is investigated. It is also shown that the increasing values of ion-neutral collisionality leads to a decrease of sheath thickness, increase of sheath potential and net space charge density in the sheath region.

6 illus, 36 ref

000139   PAKARZADEH H, GOLABI R, AMIRI I S, MAITI R, SORGER V J, YUPAPIN P (Ton Duc Thang Univ, Ho Chi Minh City, Vietnam, Email: irajsadeghamiri@tdtu.edu.vn) : Two-pump optical parametric amplification in the S-band using a tellurite microstructured optical fiber. Indian J Phys 2019, 93(1), 101–5.

In this paper, two-pump optical parametric amplification (OPA) of S-band signals based on a tellurite microstructured optical fiber (MOF) is proposed and simulated. Since the length required to obtain high parametric gain reduces dramatically since, tellurite-based MOFs possess higher nonlinear parameters than those of standard silica fibers. Simulation results showing a wide and flat band with a very high gain over the S-band region which implies that telluritebased fiber OPAs are comparable with the conventional thulium-doped fiber amplifiers. This unique feature may be used in diverse fields including satellite communication, microwave, and wireless network devices.

7 illus, 39 ref

000109   ALZUBADI A A, OBAID R S (Physics Dep, Baghdad Univ, Baghdad, Iraq, Email: dr.ali.a.alzubaidi@gmail.com) : Study of the nuclear deformation of some even–even isotopes using Hartree–Fock–Bogoliubov method (effect of the collective motion). Indian J Phys 2019, 93(1), 75–92.

In the present research, the nuclear deformation of the Ne, Mg, Si, S, Ar, and Kr even–even isotopes has been investigated within the framework of Hartree–Fock–Bogoliubov method and SLy4 Skyrme parameterization. In particular, the deform shapes of the effect of nucleons collective motion by coupling between the single-particle motion and the potential surface have been studied. Furthermore, binding energy, the single-particle nuclear density distributions, the corresponding nuclear radii, and quadrupole deformation parameter have been also calculated and compared with the available experimental data. From the outcome of our investigation, it is possible to conclude that the deforming effects cannot be neglected in a characterization of the structure of the neutron-rich nuclei. The relation between the single-particle motion and the potential surface leads to note that the change in the interactions between the nucleons causes the evolution of nuclear surface and leads to variation in the potential shape.

12 illus, 2 tables, 28 ref

000132   MA Y Y, NING L J (Shaanxi Normal Univ, Xi’an- 710119, China, Email: ninglijuan@snnu.edu.cn) : Stochastic P-bifurcation of fractional derivative Van der Pol system excited by Gaussian white noise. Indian J Phys 2019, 93(1), 61–6.

This paper aimed to investigate the stochastic P-bifurcation of Van der Pol oscillator with a fractional derivative damping term driven by Gaussian white noise excitation. Firstly, based on the method of stochastic averaging method and Stratonovich–Khasminskii theorem, the corresponding Fokker–Plank–Kolmogorov (FPK) equation is deduced. To describe the P-bifurcation of system, the stationary probability densities of amplitude can be obtained by solving the FPK equation. Then, the effects of the fractional order, the fractional coefficient, and the intensity of Gaussian white noise on the fractional systems are discussed in detail. The results show that increasing order $\alpha$ will change obviously the number and the height of peaks under certain parameter conditions. Finally, comparing the analytical and numerical results, a very satisfactory agreement can be found.

6 illus, 34 ref

000137   MARIN M, MASKEEN M M, ZEESHAN A, MEHMOOD O U, HASSAN M (Mathematics and Computer Science Dep, Transilvania Univ of Brasov, Brasov-500188, Romania, Email: m.marin@unitbv.ro) : Hydromagnetic transport of iron nanoparticle aggregates suspended in water. Indian J Phys 2019, 93(1), 53–9.

The current communication is reports about the transport phenomenon of iron metal (Fe) nanoparticle aggregates in water under the impact of an external imposed magnetic field over a stretching cylinder. The governed problem modeled using nonlinear coupled ordinary differential equations which are then tackled by the Mathematica software package bvph 2.0 based on the homotopy scheme. The impact of chemical dimension (d_l), fractal dimension (d_f) and radius of gyration (R_g) on flow and temperature profiles are presented through graphs. Numerical results are computed for the skin friction coefficient and heat transfer coefficients corresponding to the sundry parameters. It is concluded from the results that by increasing the number of particles in the back bone the heat transfer rate is improved, while by increasing the dead end particles the wall shear stress is improved but the heat transfer rate is decreased.

8 illus, 1 table, 37 ref

000107   AL-TABBAKH A A (Physics Dep, Al-Nahrain Univ, Baghdad 64055, Iraq, Email: tabbakh2013@gmail.com) : The behavior of the Fowler–Nordheim plot for ZnO–Cu virtual emitter arrays. Indian J Phys 2019, 93(1), 41–6.

Field emission arrays are attracting the attention of the scientific community due to their unique emission properties and potential technological applications. The present work deals with the Fowler–Nordheim (FN) plot behavior for virtual arrays composed of ZnO and Cu emitters with predefined geometrical properties. Electron emission is assumed to occur in these arrays based on fundamental electron tunneling with preserved emission characteristics in both semiconducting and metallic emitters (i.e., degree of field penetration near the emitter surface, band bending effects and saturation of the conduction band current at high fields). The effect of the emitter’s size distribution and the dependence of conduction band current saturation on emitter’s diameter for ZnO emitters are taken into consideration. Results show that the FN plot characteristics are greatly influenced by the investigated parameters signifying the complicated nature of field emission from these arrays. The present work is believed to be of significance for interpretation of field emission data and can assist further development of field emission arrays for future applications.

4 illus, 25 ref

000122   DHONDE M, DHONDE K S, PUROHIT K, MURTY V V S (Physics Dep, Prestige Institute of Engineering Management and Research, Indore, Madhya Pradesh - 452 001, Email: maheshdhonde86@gmail.com) : Facile synthesis of Cu/N co-doped TiO₂ nanoparticles and their optical and electrical properties. Indian J Phys 2019, 93(1), 27–32.

In the present work, pure and copper/nitrogen (Cu/N) co-doped TiO₂ nanoparticles (NPs) with various Cu concentrations have been synthesized via sol–gel route. The optical and electrical properties of the prepared pure and Cu/ N-doped TiO₂ NPs have been assessed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energydispersive X-ray spectroscopy (EDX), scanning electron microscope, Brunauer, Emmett and Teller method and UV–Vis spectroscopy. The results show that the addition of suitable amounts of Cu and N content in TiO₂ can alter its optical and electrical properties by extending absorption in the visible region and band gap reduction. XPS and XRD measurements suggest that some of the Ti sites are replaced by Cu atoms, while O sites are occupied by N atoms. An adequate addition of Cu/N in TiO₂ could lead to smaller particle size, higher specific surface area, increased dye adsorption and retarded charge carrier recombination. An optimized 0.3 mol % Cu/N-doped sample shows a significant change in band gap value of TiO₂ from 3.2 to 2.78 eV, enabling it to respond in the visible region. Hence, it can be used as a suitable alternative nanomaterial for dye-sensitized solar cell photoanode application and for photocatalysis operation as well.

5 illus, 1 table, 30 ref

000154   YAMUSA Y A, HUSSIN R, SHAMSURI W N W (Physics Dep, Teknologi Malaysia Univ, Johor, Malaysia, Email: yamusaabdullahi@yahoo.com) : Effect of Dy³⁺ on the physical, optical and radiative properties of CaSO₄–B₂O₃–P₂O₅ glasses. Indian J Phys 2019, 93(1), 15–26.

The unprecedented attributes of the trivalent rare earth ions-doped sulfoborophosphate glasses have led to tremendous interest in exploring their potentials for application in diverse photonic devices. Calcium sulfoborophosphate glasses doped with dysprosium ions were prepared by a melt-quenching technique with varying concentrations of Dy³⁺ that range from 0.1 to 1.0 mol %. Amorphous nature of the prepared glasses was determined using X-ray diffraction, while the presence of BO₃, BO₄, P–O–P, PO₄, P–O–B, O–P–O, SO₄ and B–O–B units was determined via FTIR study. Glass density and molar volume were found to be between 2.203 to 2.222 g cm^-3 and 48.10 to 48.80 m³ mol^-1 , respectively. The direct and indirect bandgap and Urbach’s energy were found to be within 4.183–4.312 eV, 3.423–3.718 eV and 0.381–0.447 eV energy ranges, respectively. The absorption spectra displayed nine prominent peaks centered at 351, 383, 451, 752, 799, 896, 1090, 1269 and 1670 nm corresponding to ⁶H_15/2 $\to$ ⁶P_7/2, ⁴ F_7/2, ⁴ I_15/2, ⁶F_3/2, ⁶F_5/2, ⁶F_7/2, ⁶F_9/2, ⁶H_11/2 and ⁶H_11/2 transitions. The emission spectrum of calcium sulfoborophosphate glasses doped with Dy³⁺ shows two prominent bands at 482 nm (⁴F_9/2 $\to$ ⁶H_15/2) and 572 nm (⁴F_9/2 $\to$ ⁶H_13/2) and two weak bands at 661 nm (⁴F_9/2 $\to$ ⁶H_11/2) and 684 nm (⁴F_9/2 $\to$ ⁶H_9/2) under 345 nm excitation. The calculated bonding parameters (d) were found to be ionic in nature. Judd–Ofelt parameters $\Omega$_$\lambda$ ($\lambda$ = 2, 4 and 6) have been calculated from the absorption spectra. The emission cross sections, as well as the branching ratios for two intense emission transitions ⁴F_9/2 $\to$ ⁶H_15/2 and ⁴F_9/2 $\to$ ⁶H_13/2, have been calculated. The excellent features demonstrated by the present glasses amplify their suitability for solid-state lasers, nonlinear optical and white LEDs applications.

10 illus, 8 tables, 47 ref

000119   COPUROGLU E, MAMEDOV B A (Physics Dep, Gaziosmanpasa Univ, Tokat, Turkey, Email: bamamedov@yahoo.com) : Developments in molecular electronic structure evaluation based on the self-frictional field with slater-type orbitals. Indian J Phys 2019, 93(1), 7–14.

Molecular electronic structure evaluations are investigated here using complete orthonormal sets of Guseinov $\mathrm{\psi }$^{($\mathrm{\alpha }$)} exponential-type orbitals ($\mathrm{\psi }$^{($\mathrm{\alpha }$)} ETOs), where $\mathrm{\alpha }$ = 1, 0, 1, 2, ... is the self-friction quantum number. Using two center overlap integrals over Slater-type orbitals (STOs) with same screening constants, all the one- and two-electron multicenter integrals are reformulated with the help of the Lo¨wdin alpha radial function. The proposed formula yields useful definitions that enable us to evaluate the multicenter integrals and related combined Hartree–Fock–Roothaan equations over STOs. In terms of the self-frictional field effect, the effectiveness of the method is demonstrated using the BH₃ molecule as an example application. The results of the calculation are validated using existing methods.

1 illus, 7 tables, 61 ref

000142   RAJASHEKHAR G, SREEKANTH T, APARNA Y, SARAH P (Physics Dep, Vardhaman Coll of Engineering, Shamshabad-501 218, Email: p.sarah@vardhaman.org) : Influence of dysprosium on the dielectric properties of bismuth layered structured piezoceramics. Rasayan J Chem 2019, 12(1), 324 - 8.

Piezoelectric ceramics are used for the applications of piezoelectric sensors, actuators and transducers. Bismuth Layered Structured Ferroelectric (BLSFs), a member of the Aurivillius family, has been studied for its application in FeRAMs (non-volatile Ferroelectric Random Access Memory). Besides the above usage, BLSFs also have their functions in electronics such as high-temperature sensors, resonators and other similar devices. In regards to its application as resonators, piezoelectric materials are used as inductors since BLSFs have higher operating temperatures as compared to lead-based materials such as PZT. Therefore BLSFs are ideal alternatives to PZT kind of lead-based materials for piezoelectric applications such as sensors at high temperatures. SrBi₄Ti₄O₁₅ (SBT) compounds, a four-layered member of the family of Aurivillius BLSFs are rare earth modified materials prepared by adding Dysprosium in A site (Sr_0.2Na_0.4Dy_0.4Bi₄Ti₄O₁₅) (SNDBT). They are prepared by a conventional double sintering method using planetary wet Ball Milling. XRD revealed the formation of a single phase with an orthorhombic structure. Scanning Electron Microscopy (SEM) is used for sample microstructure and grain size studies. The dielectric loss and dielectric constant at various temperatures and frequencies are studied.

4 illus, 1 table, 18 ref

026284   GHASEMINEZHAD S Z, SADREMOMTAZ A, RAJABI H (Physics Dep, Guilan Univ, Tehran, Iran, Email: sadrmomtaz@ guilan.ac.ir) : Validation of GATE for bone and bone marrow with calculation specific absorbed fraction for photons. J Can Res Ther 2018, 14(3), 647-50.

GATE/GEANT is a Monte Carlo code dedicated to nuclear medicine that allows calculation of the dose to organs (bone and bone marrow) of voxel phantoms. On the other hand, Medical Internal Radiation Dose (MIRD) is a well‑developed system for estimation of the dose to human organs. In this study, results obtained from GATE/GEANT using leg of Snyder phantom is compared to published MIRD data. For this, the mathematical leg of Snyder phantom was discretized and converted to a digital phantom of 100 × 100 × 200 voxels. The activity was considered uniformly distributed within bone and bone marrow. The GATE/GEANT Monte Carlo code was used to calculate the dose to the bone and bone marrow of the leg phantom from mono‑energetic photons of 10, 15, 20, 30, 50, 100, 200, 500 and 1000 keV. The dose was converted into a specific absorbed fraction (SAF) and the results were compared to the corresponding published MIRD data. On average, there was a good correlation between the two series of data for self‑absorption (r² = 0.99) and for cross‑irradiation (r² = 0.99). However, the GATE/GEANT data were on average 1.01 ± 0.79 % higher than the corresponding MIRD data for self‑absorption. As for cross‑irradiation, the GATE/GEANT data were on average 8.11 ± 7.95 % higher than the MIRD data. In this study, the SAF values derived from GATE/GEANT and the corresponding MIRD published data were compared. On average, the SAF values derived with GATE/GEANT showed an acceptable correlation and agreement with the MIRD data for the photon energies of 50–1000 keV. For photons of 10–30 keV, there was an only poor agreement between the GATE/GEANT results and MIRD data.

2 illus, 3 tables, 27 ref

002652   LI Z, LI C (China Three Gorges Univ, Yuchang 443 002, China, Email: lizhenhua1993@163.com) : A portable online current monitoring system with high precision. Mapan - J Metrol Soc India 2019, 34(2), 159–67.

The monitoring of current is great significance to evaluate the running state of electrical equipments. In this paper, a portable high-precision online current detection system is presented, and a current sensor is designed which can be opened-closed conveniently. The current sensors have the same frame structure and size, but the number of turns is different. Coils with fewer turns are used to measure the large current, and coils with more turns are used to measure the weak current. By the cooperation of two coils, the accurate measurement of current in a large dynamic range can be achieved and has the advantages of easy installation and small size. In order to improve the accuracy, an improved digital integration algorithm is proposed. The results show that the error of the system is not more than 0.7% when the current ranges from 0 to 1 A, and the error is not more than 0.21% when the current is between 1 and 100 A.

18 illus, 25 ref

002651   LEE S, CHUNG J W (Korea Research Institute of Standards and Science, Daejeon 34113, Republic of Korea, Email: llsjun@kriss.re.kr) : Monitoring of the drift of the Pt–Ir kilogram prototypes of KRISS, traceable to BIPM as-maintained mass unit. Mapan - J Metrol Soc India 2019, 34(2), 135–42.

The Bureau International des Poids et Mesures (BIPM) announced recently that its as-maintained mass unit had been changed as the result of Extraordinary Calibration. Following that amendment, the mass change of the national prototype of the kilogram (NPK) of Korea, No. 72, did not show the positive rate of drift shown in other Pt–Ir prototypes. Before the amendment, the drift rate was incorrectly evaluated to have a positive slope as a time evolution. However, we have collected measurement data for two other prototypes, Nos. 39 and 84, for about 15 years in an annual comparison with the NPK. Our periodic monitoring found drifts of a few micrograms in transit as it crossed international borders. Inspired by the new amendment of the reference prototype, our analysis of linear and exponential modeling with the least square method indicated that the modeling results of the mass change of prototypes Nos. 39 and 84 were very similar to those of earlier studies, regardless of the way we assign reference values. Prototype No. 39 notably showed unexpected behavior in the third verification: It recovered to about 1.0 lg/year, the normal rate of mass change. Different from our intuition, the mass drift of the prototype did not seem to be heavily influenced by a physically poor surface. However, in assigning the reference value in an interpolated manner, this study gives the lowest uncertainty of fitting parameters considered as evidence to prove the validity of the last evolution of the BIPM as-maintained mass unit.

5 illus, 3 tables, 20 ref

026286   KHAN M, JAYACHANDRAN P, MANOJ B (Physics and Electronics Dep, Christ Univ, Bengaluru- 560 029, Email: manoj.b@christuniversity.in) : Synthesis of graphene oxide nano structures from kerosene soot and its impedance analysis. Asian J Chem 2018, 30(5), 988-92.

Graphene oxide was synthesized from kerosene soot, by adapting three different treatments. The properties of each sample were studied using X-ray diffraction, UV-visible spectroscopy, FTIR and impedance measurements. The XRD results showed that the structural parameters (layer spacing, number of layers) were in agreement with expected values, indicating the reliability of kerosene soot as a precursor for graphene. The grain size was found to be small (1 to 2 nm) confirming the nanostructure of kerosene soot. The UV-visible spectra revealed high band gap even while conductivity was appreciably high. Other characteristic measurements showed frequency-independent conductivity, low resistance and low capacitance. FTIR spectra of all the treated samples and the precursor show the differences brought about in functionalization, due to the different methods of treatment. These differences, however, does not appreciably affect parameters such as band gap, conductivity and dielectric loss in any drastic way.

5 illus, 1 table, 16 ref

026285   KANAKARAJ M, RAMALINGAM H B (Physics Dep, Government Arts Coll, Udumalpet- 642 126, Email: kanagarajbu@gmail.com) : Effect of bath temperature on magnetic and structural properties of electrodeposited NiFeCr nano crystalline thin films. Asian J Chem 2018, 30(5), 967-71.

Soft magnetic thin films of NiFeCr were prepared using electrodeposition in various bath temperature. NiFeCr deposited films are textured with FCC phase preferred orientation. Experimentally observed soft magnetic property of thin films for different temperature was compared. The addition of chromium can enhance magnetic and mechanical properties of NiFe thin films. Electrodeposited NiFeCr films were prepared at different temperature (30, 50, 70 and 90 °C) and they were subjected to morphological, structural, magnetic and mechanical characterization analysis. Nickel content was maximum as 51.36 wt % at 90 °C. The chromium content increased when electrolytic bath temperature was increased. NiFeCr films were bright and uniformly coated on the surface. Also the deposits of NiFeCr films were in nano scale and the average crystalline size was around 30 nm. Thin films prepared at high temperature exhibited a high saturation magnetization and low coercivity. The micro hardness of NiFeCr was 272 VHN at 90 °C.

5 illus, 3 tables, 20 ref

027554   MADHAVI J, SUBRAMANYAM C, BOSE G S C, RAMANAIAH M V, RAVIKUMAR R V S S N (Physics Dep, Acharya Nagarjuna Univ, Nagarjuna Nagar- 522 510, Email: rvssn@yahoo.co.in) : Optical and EPR studies of VO²⁺ ions doped ZnS-CdS composite nanoparticles. Rasayan J Chem 2018, 11(3), 1236-43.

VO²⁺ ions doped ZnS-CdS composite nanoparticles have been synthesized by chemical precipitation method. The prepared sample was investigated by different spectroscopic techniques such as optical absorption (UV-Vis) and Electron Paramagnetic Resonance (EPR) studies. The results and analysis reveal that site the VO²⁺ ion occupied in octahedral symmetry with tetragonal compression having (C_4v) symmetry in the host lattice. Optical absorption spectrum showed characteristic bands corresponding to (d ↔ d) transitions and the corresponding band gap energies are calculated. The evaluated crystal field and parameters are Dq = 1757, Ds = -2652 and Dt = 1111 cm-¹, g_I = 1.90, g_^ = 1.98, A_|| = 2.11 x 10^-4, A_^= 41.38 x 10^-4 cm^-1.

2 illus, 1 table, 60 ref

027521   ALTI K (Physics Dep, Sant Gadge Baba Amravati Univ, Amravati - 444 602, Email: kamleshalti@sgbau.ac.in) : Teaching methodology for the introduction of quantum mechanics. Phys Educ 2018, 34(3), 1-5.

In most of the universities and colleges, introduction of Quantum Mechanics starts with failures of Classical Mechanics. Mathematics needed to understand quantum mechanics (operator formalism etc.) starts quite abruptly after that. This paper discusses a simple teaching approach to introduced Quantum Mechanics to the newcomers by answering some outstanding questions which students are hesitant to ask.

2 illus, 9 ref

027591   SINGAL A K (Physical Research Laboratory Navrangpura, Ahmedabad- 380 009, Email: ashokkumar.singal@gmail.com) : A heuristic derivation of radiative power loss and radiation reaction from the kinetic power of electric inertial mass of a charge. Phys Educ 2018, 34(3), 1-11.

It is shown that formulas for the radiative power loss and radiation reaction from a charge can be derived in a heuristic manner from the kinetic power (rate of change of the kinetic energy) of its electric inertial mass. The derivation assumes a non-relativistic but otherwise an arbitrary motion of the charge. We exploit the fact that as the charge velocity changes because of a constant acceleration, there are accompanying modi cations in its electromag- netic elds which can remain concurrent with the charge motion because the velocity as well as acceleration information enters into the eld expression. However, if the acceleration of the charge is varying, information about that being not present in the eld expressions, the electromagnetic elds get \out of step" with the actual charge motion. Accordingly we arrive at a radiation reaction formula for an arbitrarily moving charge, obtained hitherto in literature from the self-force, derived in a rather cumbersome way from the detailed mutual interaction between various constituents of a small charged sphere. This way we demonstrate that a power loss from a charge occurs only when there is a change in its acceleration and the derived instantaneous power loss is directly proportional to the scalar product of the velocity and the rate of change of the acceleration of the charge.

37 ref

027525   ASHDHIR P, SAXENA Y, KUSHWAHA A (Physics Dep, Delhi Univ, Delhi - 110 007, Email: pragatiashdhir@hinducollege.ac.in) : Inertial versus non-inertial frame of reference. Phys Educ 2018, 34(3), 1-10.

In this paper, we have solved a rotational dy- namics problem both in Inertial and Non-inertial frames of reference. The work presents a comparison of the analysis in the two frames and comments on math- ematical and physical concepts involved in solving the problem. The results are then rep- resented in terms of simulations and solutions are thoroughly discussed, in an e ort to give students, a clear picture of the importance of the two frames. The article is aimed at the undergraduate level students.

8 illus, 5 ref

027598   SURESH T P, DAMODARAN L, UDAYANANDAN K M (Physics Dep, Kannur Univ, Kerala- 671 314, Email: udayanandan@gmail.com) : Thermodynamics of polar systems. Phys Educ 2018, 34(3), 1-4.

Equation of state for a polarized system is obtained using canonical ensemble. Energy of the system based on mean eld treatment is used for the purpose. The equation of state obtained matches with the van der Waals equation of state.

12 ref

027590   SINGAL A K (Physical Research Laboratory Navrangpura, Ahmedabad - 380 009, Email: ashokkumar.singal@gmail.com) : Locating planets in sky using manual calculations. Phys Educ 2018, 34(3), 1-8.

In this article, we describe a very simple technique to locate naked-eye planets in the sky, to an accuracy of ~ 1°, up to say, 2050 AD. The procedure, comprising just three steps, involves very simple manual calculations for planetary orbits around the Sun; all one needs are the initial speci cations of planetary positions for some standard epoch and the time periods of their revolutions. After applying a small correction for the orbital ellipticity, appearance of a planet relative to Sun's position in sky, as seen by an observer from Earth, is found using a scale and a protractor (found inside a school geometry box).

2 illus, 3 tables, 4 ref

028765   JEBA K A, LATHA M M, JAIN S R (Physics Dep, Women’s Christian Coll, Nagercoil 629 001, Email: lathaisaac@gmail.com) : Influence of quadrupole–quadrupole-type interaction on the chaotic dynamics of α-helical proteins. Pramana - J Phys 2018, 91(3), 40.

By proposing a model Hamiltonian in the first quantised form we investigate the chaotic dynamics of α-helical proteins by taking into account the quadrupole–quadrupole-type interaction. The dynamics is studied by deriving Hamilton’s equations of motion and by plotting the time-series evolution and phase-space trajectories. Chaotic trajectories are observed in the phase-space plots. The effect of the interaction parameters on the stability of proteins is also discussed.

6 illus, 4 tables, 39 ref

028752   CHAITANYA K V S S (Physics Dep, Hyderabad Campus, Hyderabad - 500 078, Email: chaitanya@hyderabad.bits-pilani.ac.in) : Harmonic oscillator wigner function extension to exceptional polynomials. Pramana - J Phys 2018, 91(3), 39.

In this paper, we construct isospectral Hamiltonians without shape invariant potentials for a harmonic oscillator Wigner function on a real line. In this case, we actually remove the ground state of the second Hamiltonian, which forms a special case, m = 0, of an exceptional Laguerre differential equation with solutions {L_n⁻² }∞ _n=2 as eigenfunctions form a complete orthogonal set in the Hilbert space.

29 ref

028766   JIA P, YANG J, LIU H, HU E (Mechanical Engineering Dep, Michigan Univ, Ann Arbor, MI 48109, USA, Email: jianhuayang@cumt.edu.cn) : Improving amplitude-modulated signals by re-scaled and twice sampling vibrational resonance methods. Pramana - J Phys 2018, 91(3), 38.

We present the re-scaled vibrational resonance (VR) method and the twice sampling VR method to improve the amplitude-modulated signal. Two different kinds of signals are considered. One is the amplitudemodulated harmonic signal. The other is the amplitude-modulated aperiodic binary signal. Both the VR methods have an excellent effect on the signal improvement. For the re-scaled VR method, the scale parameter is the key factor to determine the resonance output. For the twice sampling VR method, the frequency reduced ratio or the minimal random pulse width stretched ratio is the crucial factor. By choosing appropriate key factors, the output can achieve the strongest resonance and lead to the optimal signal improvement.

14 illus, 36 ref

028789   YANG S (ATM Dep, Civil Aviation Flight Univ of China, Guanghan 618307, People’s Republic of China, Email: yangshushuer@126.com) : The envelope travelling wave solutions to the Gerdjikov–Ivanov model. Pramana - J Phys 2018, 91(3), 36.

In this paper, by using the complete discrimination system of the polynomial method, the classification of the envelope travelling wave solutions to the Gerdjikov–Ivanov model is obtained. The complete result shows that there exist rich patterns of travelling wave solutions to the Gerdjikov–Ivanov model, including solitary solutions, periodic solutions, rational singular solutions and double periodic continuous and non-continuous solutions. Among those, some new solutions are given.

46 ref

028760   GHERGHEREHCHI M, KO J, ARABYARMOHAMMADI N, AFARIDEH H, KIM Y S (Korea Univ of Technology and Education (KOREATECH), Cheonan, Republic of Korea, Email: yoonsang@koreatech.ac.kr) : Optimisation of a hybrid photoneutron source in a linear accelerator using GEANT4 and MCNPX Monte Carlo codes. Pramana - J Phys 2018, 91(3), 35.

Radiotherapy is important for treating oral cancer in advanced stages. Boron neutron capture therapy represents a unique modality in which neutron beams penetrate into the tissue within an epithermal range. Different methods are available for neutron production, and in this study, we used an electron accelerator. A photoneutron source based on three different energy values (10, 25, and 50 MeV) of a linear accelerator electron beam was designed using GEANT4 (GEometry ANd Tracking) and MCNPX (Monte Carlo N-Particle eXtended) simulation codes. The results indicate that a hybrid photoneutron source introduced tungsten and uranium with BeO. The statistical uncertainties in all simulations were less than 0.3 and 0.07 % for MCNPX and the standard electromagnetic physics packages of GEANT4, respectively. Various cross-sectional and stopping-power data and different physics simulations produced different distributions.

16 illus, 2 tables, 19 ref

028786   ULLAH S, GUSEV G M, BAKAROV A K, HERNANDEZ F G G (Physics Dep, Gomal Univ, Dera Ismail Khan 29220, KP, Pakistan, Email: saeedullah.phy@gmail.com) : Tailoring multilayer quantum wells for spin devices. Pramana - J Phys 2018, 91(3), 34.

Time-resolved Kerr rotation and resonant spin amplification techniques were used to study the spin dynamics in multilayer GaAs/AlGaAs quantum wells. The spin dynamics was regulated through the wave function engineering and quantum confinement in multilayer quantum wells. We observed the spin coherence with remarkably long dephasing time T₂^∗>13 ns for the structure doped beyond metal–insulator transition. Dyakonov–Perel spin relaxation mechanism, as well as the inhomogeneity of electron g-factor, was suggested as the major limiting factor for the spin coherence time. In the metallic regime, we found that the electron–electron collisions become dominant over microscopic scattering on the electron spin relaxation with the Dyakonov–Perel mechanism. Furthermore, the data analysis indicated that in our structure, due to the spin relaxation anisotropy, the Dyakonov–Perel spin relaxation mechanism is efficient for the spins oriented in-plane and suppressed along the quantum well growth direction resulting in the enhancement of T₂^∗ . Our findings, namely, long-lived spin coherence persisting up to high temperature, spin polarisation decay time with and without magnetic field, the spin–orbit field, single electron relaxation time, transport scattering time and the electron–electron Coulomb scattering time highlight the attractiveness of n-doped multilayer systems for spin devices.

4 illus, 1 table, 48 ref

028751   BHUYAN K, BHATTACHARJEE A, ALAPATI P R (Physics Dep, North Eastern Regional Institute of Science and Technology, Nirjuli 791 109, Email: bhuyankakali@gmail.com) : Sensing of ammonia gas by undoped and aluminum-doped tin oxide nanoparticles by Raman spectroscopy. Pramana - J Phys 2018, 91(3), 32.

The study of gas sensing properties of SnO₂ has been widely carried out mainly using electrical methods where a change in resistance or/and conductance of SnO₂ is measured when it is exposed to the sample. In this work, a spectroscopic approach was employed using Raman intensity as a tool to study the sensing of ammonia by undoped and aluminum-doped SnO₂ nanoparticles. The study showed a variation of intensity of the classical Raman modes of SnO₂, when SnO₂ was exposed to ammonia. The response to ammonia by nanoparticles of different sizes and doping concentrations was calculated. This study also revealed the optimum crystallite size and doping concentration suitable for sensing ammonia. However, the most important conclusion that could be drawn from this study was that the response of SnO₂ to ammonia could be detected at room temperature through Raman spectroscopy unlike in the case of electrical studies, where a high temperature is required for sensing.

3 illus, 6 tables, 41 ref

028787   USHCATS S, USHCATS M, BULAVIN L, SVECHNIKOVA O, MYKHELIEV I (Molecular Physics Dep, Taras Shevchenko Univ of Kiev, Kiev 03680, Ukraine, Email: mykhailo.ushcats@nuos.edu.ua) : Asymptotics of activity series at the divergence point. Pramana - J Phys 2018, 91(3), 31.

For statistical models of imperfect gases, a new method is proposed to evaluate the reducible cluster integrals of very high (actually unlimited) orders on the basis of information on the irreducible integrals (virial coefficients) or information on the corresponding radius of convergence for the virial series in powers of activity. This method is used to transform conventional expansions for pressure and density in powers of activity to a functional form that allows the analytical study of those series at the vicinity of their divergence point. In particular, the results of this study confirm the adequacy of the cluster-based approach at the condensation region and agree with the results of the previous studies of partition function in terms of irreducible integrals.

1 illus, 30 ref

028759   GASANLY N (Physics Dep, Middle East Technical Univ, 06800 Ankara, Turkey, Email: nizami@metu.edu.tr) : Optical properties of TlGa(S_xSe_1−x)₂ layered mixed crystals (0 ≤ x ≤ 1): Absorption edge and photoluminescence study at T = 10 K. Pramana - J Phys 2018, 91(3), 30.

Transmittance measurements of TlGa(S_xSe_1−x )₂ layered mixed crystals (0 ≤ x ≤ 1) were performed in the 1.80–2.80 eV photon energy range at T = 10 K. Band-gap energies of the studied crystals were estimated by means of the derivative spectra of transmittance and photon energy dependence of absorption coefficient. The compositional dependence of direct band-gap energy at T = 10 K revealed that as sulphur (selenium) composition is increased (decreased) in the mixed crystals, the direct band-gap energy increases from 2.19 eV (x = 0) to 2.67 eV (x = 1). Photoluminescence spectra of TlGa(S_xSe_1−x )₂ mixed crystals were investigated in the photon energy region of 2.00–3.10 eV at T = 10 K. The observed bands were assigned to the transitions of electrons from conduction band to the shallow acceptor levels in the band gap. The shift of the PL bands to higher energies with increasing sulphur content was revealed. In addition, the composition ratio of the mixed crystals was obtained from the energy-dispersive spectroscopy experiments.

6 illus, 23 ref

030010   YANG G, CHEN X, XUAN W, CHEN Y (Wuhan Univ, Wuhan 430072, China, Email: yangguoneo@hotmail.com) : Dynamic compressive and splitting tensile properties of concrete containing recycled tyre rubber under high strain rates. Sadhana 2018, 43(11), 178.

In order to raise the efficiency of resource utilization, recycling waste rubber particles into concrete as aggregate has been widely accepted. When the size and content of the rubber particles are appropriate, rubberized concrete can achieve many excellent properties. This study investigated the impact of rubber replacement on dynamic compressive and splitting tensile properties of concrete. The split Hopkinson pressure bar tests of rubberized concrete containing 5 %, 10 %, 15 % and 20 % volume replacement for sand were completed. The failure modes, stress curves and dynamic strength values of rubberized concrete under high strain rates were recorded. The results reveal that the dynamic compressive and splitting tensile strength of rubberized concrete decrease with increasing rubber content. Meanwhile, peak strain increases with increasing rubber content. Dynamic increase factors (DIFs) of compressive and splitting tensile strength also were calculated, where rubberized concrete shows a stronger strain rate sensitivity. The analysis of specific energy absorption illustrates that rubberized concrete with 15 % rubber replacement has the best impact toughness. In addition, ratios of dynamic compressive–tensile strength of rubberized concrete were calculated, which are between 3.82 and 5.39.

26 illus, 5 tables, 38 ref

029951   AGRAWAL Y, GIRISH M, CHANDEL R (Dhirubhai Ambani Institute of Information and Communication Technology, Ganghinagar - 382 007, Email: mr.yashagrawal@gmail.com) : An efficient and novel FDTD method based performance investigation in high-speed current-mode signaling SWCNT bundle interconnect. Sadhana 2018, 43(11), 175.

Carbon nanotube (CNT) has emerged as the most extensively researched area in nanoscience and amongst the frontrunners in co-triggering the nanotechnology revolution. Single-wall CNT (SWCNT) bundle is a part of CNT family and has been proposed as the future nano-wires in integrated circuits. The present paper analyzes the performance of SWCNT bundle interconnect with high-speed current-mode signaling (CMS) scheme using efficient finite-difference time-domain (FDTD) method. For the first time, FDTD based method is explored for modeling CMS SWCNT bundle interconnect incorporating practical CMOS driver gate. The CMOS gate is characterized by n^th power-law model. The stability of FDTD method is ascertained by Courant condition. The proposed FDTD based method is efficient and can be used for performance analyses of future nano-wire SWCNT bundle as well as conventional copper interconnects. At the same time, this method is applicable for both traditional full-voltage swing voltage-mode signaling (VMS) and remarkable low-voltage swing CMS schemes. The various analyses in the paper reveal that CMS SWCNT bundle interconnect has higher edge over CMS copper interconnect in terms of smaller delay, lesser crosstalk induced delay and noise. The proposed analytical FDTD based method is validated using Tanner-SPICE EDA simulation tool. The maximum error between the FDTD and SPICE for the transient response in CMS SWCNT bundle interconnect for 32 nm technology node is within 3 %.

10 illus, 4 tables, 48 ref

029949   ABDULLAH B J, OMAR M S, JIANG Q (Physics Dep, Salahaddin-Erbil Univ, Kurdistan Region 31019, Iraq, Email: botan_nano@yahoo.com) : Size dependence of the bulk modulus of Si nanocrystals. Sadhana 2018, 43(11), 174.

This study investigates the effect of size on bulk modulus and its related parameters, including melting temperature and mass density based on the ratio number of surface atoms to that of its internal. The equation of bulk modulus in the bulk state B(∞) is modified to include the related size-dependent parameters without any adjustable parameter, and is applied to Si nanocrystals. The bulk modulus B(r) decreases from 9.8 × 10¹⁰ N m² for the bulk state to 5.93 × 10¹⁰ N m² for a 5 nm diameter of Si nanoparticles. An inherent relation between bulk modulus and change of the lattice parameter in nanocrystals obtained from the variation in the surface to volume ratio, this leads to increase in the mean bond length. The effect of mass density and melting temperature on bulk modulus are also discussed. Calculated results for bulk modulus are verified by experimental as well as the available computer simulation data.

5 illus, 37 ref

029976   KARIKALAN N (Physics Dep, Hindustan Institute of Technology and Science, Chennai, Tamil Nadu, Email: sivakanikari@gmail.com) : Synthesis and charaterization of copper nanoparticles and evaluation of antibacterial activity. Rasayan J Chem 2018, 11(4), 1451-7.

The nanotechnology has been developed in recent years due to the wide application in the human beings. One of the famous nanomaterials is copper nanoparticles. The copper nanoparticles have been reported to have strong antibacterial activity. Nowadays there are many environmental problems and illness caused by the microbial pathogen. It is widely agreed that nanoparticles are clusters of atoms in the size range of 1–100 nanometer. The present study included the chemical reduction of copper chloride through trisodium citrate and testing for their antimicrobial activity. The aqueous copper chloride exposed to the trisodium citrate results in the synthesis of copper nanoparticles. The pH and viscosity of the copper nanoparticles monitored and indicates the stability of the particles. Ultraviolet-visible spectrum and Fourier-transform infrared spectroscopy further confirmed in the synthesized copper nanoparticles. These synthesized copper nanoparticles were further confirmed by using a scanning electron microscope. The scanning electron microscope analysis showed the particle size between 44.50 nanometers as well the spherical structure of the nanoparticles. The proven antibacterial activity of synthesized copper nanoparticles against Escherichia coli established. It is confirmed that copper nanoparticles are capable of rendering high antibacterial efficacy and hence has a great potential in the preparation of drugs used against bacterial diseases. Applications of copper nanoparticles based on these findings may lead to valuable discoveries in various fields such as medical devices and antimicrobial systems.

4 illus, 2 tables, 14 ref

029955   BHUI P, SIDDIQUI Q T, MUNEER M, AGARWAL N, BOSE S (Mumbai Univ, Maharashtra - 400 098, Email: na@cbs.ac.in) : Deep blue organic light-emitting diodes of 1,8-diaryl anthracene. J Chem Sci 2018, 130(12), 167.

We report on the optimization of organic light emitting diode (OLED) devices using 1,8-di-(4- trifluromethylphenyl)-anthracene (CF3-DPA) as the active emissive layer. CF3-DPA emits in the deep blue region with an emission peak at 432 nm in solution which showed a slight red shift in thin films. CF3-DPA has high reported fluorescence quantum efficiency, $~$67 %, as compared to 9,10-diphenyl anthracene (9,10-DPA). We optimized the OLED devices with different hole transporting layers (HTLs). Bilayer devices formed with N,N$\text{'}$ -di(1-naphthyl)-N,N$\text{'}$ -diphenyl-(1,1$\text{'}$ -biphenyl)-4,4$\text{'}$ -diamine (NPD) as the HTL gave a reasonable light output. We observed that trilayer or multilayer devices with the inclusion of poly(3,4-ethylene dioxythiophene)- poly(styrene sulfonate) (PEDOT:PSS) and/or copper phthalocyanine as an additional HTL reduced the turn on voltage by ∼5 to 9 V, though the brightness of the light emission also decreased. Including suitable carrier (electron or hole) transporting layers like 2, 2$\text{'}$ ,2$\text{'}\text{'}$-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) and 4,4$\text{'}$ -Bis(N-carbazolyl)-1,1$\text{'}$ -biphenyl (CBP) increases the efficiency of the devices. From our studies, we conclude that though NPD/CF3-DPA interface is crucial for light emission, the performance of the devices is limited by the mismatch of the hole and electron mobilities and the low internal quantum efficiency of CF3-DPA in the solid state. Devices having ITO/NPD/CF3-DPA/TPBi/LiF-Al geometry were observed to be the most efficient.

6 illus, 31 ref

029986   PARANTHAMAN S, SAMPATHKUMAR S, MURUGASENAPATHI N K (Physics Dep, Kalasalingam Academy of Research and Education (Deemed to be Univ), Tamil Nadu - 626 126, Email: psrengan@hotmail.com) : Density functional benchmark studies on structure and energetics of 3d transition metal mononitrides. J Chem Sci 2018, 130(12), 164.

We report the results of a benchmarking study on generalized gradient approximation (GGA), metaGGA, hybrid GGA, and hybrid meta-GGA density functional theory (DFT) methods for 3d transition metal mononitrides (3d-TMNs). The selected DFT functionals are, B97-D, BLYP, BP91, MPW91, PBE96, PW91, M06-L, B3LYP, B97, BHandH, PBE0, M05, M05-2X, M06, M06-2X, M06-HF and TPSSh. The performances of these DFT functionals are assessed by calculating the bond distance, harmonic vibrational frequency and atomization energy of 3d-TMNs. The results are compared with the available experimental and high-level ab initio results. The calculated results show that MPW91, M06-L, and B3LYP functionals provide better results than the other functionals that are taken in this study. In general, the functionals with significant Hartree–Fock exchange show poor performance in most of the 3d-TMNs. Hence, these functionals are not recommended for the studies of structure and energetics in 3d-TMNs.

2 illus, 5 tables, 65 ref

029997   SHARMA R, SHARMA S D, SARKAR P S, DATTA D (Radiological Physics and Advisory Div, Bhabha Atomic Research Centre, Mumbai - 400 094, Email: rmks_sharma@yahoo.com) : Imaging and dosimetric study on direct flat panel detector based digital mammography system. J Med Phys 2018, 43(4), 255-63.

Image quality of digital mammography system is generally defined by three primary physical parameters, namely, contrast, resolution, and noise. Quantification of these metrics can be done by measuring objective image quality parameters defined as contrast‑to‑noise ratio (CNR), modulation transfer function (MTF), and noise power spectra (NPS). In the present study, various imaging metrics such as CNR, contrast detail resolution, MTF, and NPS were evaluated for a direct flat‑panel detector‑based digital mammography system following the European Guidelines. Furthermore, system performance relating to both image quality and doses were evaluated using figure of merit (FOM) in terms of  CNR2 /mean glandular dose (MGD) under automatic exposure control (AEC) and clinically used OPDOSE operating mode. Under AEC mode, FOM values for the 4.5 cm thick BARC polymethyl methacrylate (PMMA) phantom were found to be 15.02, 15.88, and 19.82 at Mo/Mo, Mo/Rh, and W/Rh target/filter (T/F), respectively. Under OPDOSE mode, FOM values were found to 65.32, 11.80, and 1.14 for the BARC PMMA phantom thickness of 2, 4.5, and 8 cm, respectively. Under OPDOSE mode, the calculated MGD values for three Computerized Imaging Reference Systems slab phantoms having total thickness of 7 cm were observed to be 3.03, 2.32, and 1.75 mGy with glandular/adipose tissue compositions of 70/30, 50/50, and 30/70, respectively, whereas for the 2–8‑cm thick BARC PMMA phantom, the calculated MGDs were found to be in the range of 0.57–3.32 mGy. All the calculated MGDs values were found to be lower than the acceptable level of dose limits provided in European Guidelines.

11 illus, 5 tables, 35 ref

029978   LEE S-W, SOZONTOV E, STRUMBAN E, YIN F-F (Radiation Oncology Dep, Maryland Univ School of Medicine, Maryland, USA, Email: sungwoolee@umm.edu) : Dosimetric characterization of an intensity modulated X-ray brachytherapy system. J Med Phys 2018, 43(4), 247-54.

An intensity‑modulated X‑ray brachytherapy system is being developed for various clinical applications. This new system makes it possible for clinical staff to control energy as well as dose rate for different tumor sites according to their sizes and radiobiological characteristics. This system is mainly composed of an X‑ray tube, guide tube collimation, and secondary (pseudo) target. Due to its configuration, convenient modulations of fluorescent X‑ray energy and intensity are possible. To observe applicability of this novel system for various primary and secondary target combinations, Monte Carlo simulation using MCNP5 was performed, and air measurements were done. As a primary and pseudo‑target combination, silver–molybdenum (Ag‑Mo), tungsten–neodymium (W‑Nd), and tungsten–erbium (W‑Er) were used for the calculation for dose profile. Specifically, a dose distribution was calculated around each of these target combinations. Dose distributions as a function of target angles were also calculated. The Ag‑Mo combination was analyzed for Cartesian coordinates of xy, xz, and yz planes of the pseudo‑target to observe dose distribution as a function of the angle of secondary target. The results showed that radial dose fall‑off of Ag‑Mo was greater than commercially available brachytherapy sources (¹⁰³Pd and ¹²⁵I) due to its low characteristic X‑ray energy. Dose distribution variance should be considered in beam modulation for clinical application. Dynamic movement of the pseudo‑target is feasible and remains as a subject for future research.

9 illus, 2 tables, 17 ref

029980   MAHUVAVA C, PLESSIS F C P D (Medical Physics Dep, The Free State Univ, Bloemfontein, South Africa, Email: duplessisfcp@ufs.ac.za) : Dosimetry effects caused by unilateral and bilateral hip prostheses: A Monte Carlo case study in megavoltage photon radiotherapy for computed tomography data without metal artifacts. J Med Phys 2018, 43(4), 236-46.

Hip prostheses (HPs) are routinely used in hip augmentation to replace painful or dysfunctional hip joints. However, high‑density and high‑atomic‑number (Z) inserts may cause dose perturbations in the target volume and interface regions. To evaluate the dosimetric influence of various HPs during megavoltage conformal radiotherapy (RT) of the prostate using Monte Carlo (MC) simulations. BEAMnrc and DOSXYZnrc MC user‑codes were respectively used to simulate the linac head and to calculate 3D absorbed dose distributions in a computed tomography (CT)‑based phantom. Anovel technique was used to synthetically introduce HPs into the raw patient CT dataset. The prosthesis materials evaluated were stainless steel (SS316L), titanium (Ti6Al4V), and ultra‑high‑molecular‑weight polyethylene (UHMWPE). Four, five, and six conformal photon fields of 6–20 MV were used. The absorbed dose within and beyond metallic prostheses dropped significantly due to beam attenuation. For bilateral HPs, the target dose reduction ranged up to 23 % and 17 % for SS316L and Ti6Al4V, respectively. For unilateral HP, the respective dose reductions were 19 % and 12 %. Dose enhancement was always < 1 % for UHMWPE. The 6‑field plan produced the best target coverage. Up to 38 % dose increase was found at the bone–SS316L proximal interface. The novel technique used enabled the complete exclusion of metal artifacts in the CT dataset. High‑energy plans with more oblique beams can help minimize dose attenuation through HPs. Shadowing and interface effects are density dependent and greatest for SS316L, while UHMWPE poses negligible dose perturbation.

10 illus, 7 tables, 32 ref

029973   INUI S, UEDA Y, OHIRA S, ISONO M, MASAOKA A, MURATA S, NITTA Y, KARINO T, MIYAZAKI M, TESHIMA T (Radiation Oncology Dep, Osaka International Cancer Institute, Osaka 537-8511, Japan, Email: ueda-yo@mc.pref.osaka.jp) : Comparison of interfractional setup reproducibility between two types of patient immobilization devices in image guided radiation therapy for prostate cancer. J Med Phys 2018, 43(4), 230-5.

The aim of this study is to compare the interfractional setup reproducibility of two types of patient immobilization devices for prostate cancer receiving image‑guided radiation therapy (IGRT). The MOLDCARE (MC) involves hydraulic fixation, whereas the BlueBAG (BB) and Vac‑Lock (VL) involve vacuum fixation. For 72 patients, each immobilization device was individually customized during computed tomography (CT) simulation. Before the treatment, bony registration was performed using orthogonal kV images and digitally reconstructed radiographs. The shift of the treatment couch was recorded as a benchmark in the first session. In subsequent sessions, the shifts from the benchmark were measured and analyzed. Soft‑tissue registration was performed weekly by cone‑beam CT and CT images, and the shifts were measured and analyzed. In the superior‑inferior and left‑right directions, there were nearly no changes in the overall mean among the immobilization devices. In the anterior‑posterior (AP) direction, the overall mean for the MC, BB, and VL were 0.34 ± 1.33, −0.47 ± 1.27, and −1.82 ± 1.65 mm, respectively. The mean shifts along the AP direction were approximately 1 mm more in patients immobilized on the BB and 2.5 mm more in those on the VL, compared to those on the MC, after the twentieth treatment. No significant changes were observed among the patients immobilized on those devices, respectively, in soft‑tissue registration. It can be concluded that the settling of the vacuum fixation was caused by air leakage in the latter‑half treatment, and the immobilization device type has no effect on the treatment‑position reproducibility in IGRT

3 illus, 4 tables, 25 ref

029962   DEPEW K D, AHMAD S, JIN H (Radiation Oncology Dep, Oklahoma Health Sciences Centre Univ, Oklahoma, USA, Email: hosang-jin@ouhsc.edu) : Experimental assessment of proton dose calculation accuracy in small field delivery using a mevion S250 proton therapy system. J Med Phys 2018, 43(4), 221-9.

Dose calculation accuracy of the Varian Eclipse treatment planning system (TPS) is empirically assessed for small‑aperture fields using a Mevion S250 double scattering proton therapy system. Five spherical pseudotumors were modeled in a RANDO head phantom. Plans were generated for the targets with apertures of 1, 2, 3, 4, or 5 cm diameter using one, two, and three beams. Depth‑dose curves and lateral profiles of the beams were taken with the planned blocks and compared to Eclipse calculations. Dose distributions measured with EBT3 films in the phantom were also compared to Eclipse calculations. Film quenching effect was simulated and considered. Depth‑dose scans in water showed a range pullback (up to 2.0 mm), modulation widening (up to 9.5 mm), and dose escalation in proximal end and sub‑peak region (up to 15.5 %) when compared to the Eclipse calculations for small fields. Measured full width at half maximum and penumbrae for lateral profiles differed < 1.0 mm from calculations for most comparisons. In the phantom study, Eclipse TPS underestimated sub‑peak dose. Gamma passing rates improved with each beam added to the plans. Greater range pullback and modulation degradation versus water scans were observed due to film quenching, which became more noticeable as target size increased. Eclipse TPS generates acceptable target coverage for small targets with carefully arranged multiple beams despite relatively large dose discrepancy for each beam. Surface doses higher than Eclipse calculations can be mitigated with multiple beams. When using EBT3 film, the quenching effect should be considered.

5 illus, 5 tables, 24 ref

029984   MENON S V, PARAMU R, BHASI S, NAIR R K (Radiation Physics Div, Regional Cancer Centre, Thiruvananthapuram - 695 011, Email: sharika.menon@gmail.com) : Evaluation of plan quality metrics in stereotactic radiosurgery/radiotherapy in the treatment plans of arteriovenous malformations. J Med Phys 2018, 43(4), 214-20.

Several plan quality metrics are available for the evaluation of stereotactic radiosurgery/radiotherapy plans. This is a retrospective analysis of 60 clinical treatment plans of arteriovenous malformation (AVM) patients to study clinical usefulness of selected plan quality metrics. The treatment coverage parameters Radiation Therapy Oncology Group (RTOG) Conformity Index (CI_RTOG), RTOG Quality of Coverage (Q_RTOG), RTOG Homogeneity Index (HI_RTOG), Lomax Conformity Index (CI_Lomax), Paddick’s Conformity Index (CI_Paddick), and dose gradient parameters Paddick’s Gradient Index (GI_Paddick) and Equivalent Fall-off Distance (EFOD) were calculated for the cohort of patients. Before analyzing patient plans, the influence of calculation grid size on selected plan quality metrics was studied on spherical targets. It was found that the plan quality metrics are independent of calculation grid size ≤ 2 mm. EFOD was found to increase linearly with increase in target volume, and a linear fit equation was obtained. The analysis shows that RTOG indices and EFOD would suffice for routine clinical radiosurgical treatment plan evaluation if a dose distribution is available for visual inspection.

11 illus, 2 tables, 18 ref