025043   SAINI P, SHARMA R, PANT R P, KOTNALA R K (CSIR-National Physical Laboratory, New Delhi- 110 012, Email: pksaini@nplindia.org) : Ultrafast adsorption of organic dyes by activated-carbon@Fe₃O₄ nanoscale composites: An effective solution for water purification. Indian J Pure Appl Phys 2018, 56(3), 187- 95.

Superparamagnetic (SPM) Fe₃O₄ nanoparticles (NPs) decorated activated charcoal (AC) skeletal (AC @ Fe₃O₄) type nanoscale composites (NCs) have been prepared by a scalable and facile approach involving impregnation of AC with stable dispersion of SPM Fe₃O₄ NPs followed by controlled vacuum drying. These NCs exhibit coupled magnetic character and porosity which can be easily optimized by controlling weight ratio of two phases. The electron microscopy images show the presence of clustered Fe₃O₄ particles present all over the surface of porous AC particles and prevalence of meso-pores, which provides the channels for ingress and immobilization of sorbent moieties. The magnetometry and nitrogen adsorption measurements reveal that magnetic character increases whereas porosity decreases with the increase in Fe₃O₄ NP loading. These NCs have been demonstrated for purification of water containing methylene blue (MB) dye as an impurity. The porosity of these composites allow rapid adsorption (<1 min) of MB with good removal efficiency (> 99 %) and their magnetic behaviour helps in instantaneous separation of MB adsorbed NC particles by the application of external magnetic field. The sorbent can be reused several times after proper regeneration with retention of more than 95 % of the original adsorption capacity.

12 illus, 39 ref

024243   KONG T Y, KIM S, LEE Y, SON J K, MAENG S J (Central Research Institute, Daejeon- 34101, Republic of Korea, Email: eagertaeyoung@khnp.co.kr) : Radioactive effluents released from Korean nuclear power plants and the resulting radiation doses to members of the public. Nucl Eng Technol 2017, 49(8), 1772- 7.

Korean nuclear power plants (NPPs) periodically evaluate the radioactive gaseous and liquid effluents released from power reactors to protect the public from radiation exposure. This paper provides a comprehensive overview of the release of radioactive effluents from Korean NPPs and the effects on the annual radiation doses to the public. The amounts of radioactive effluents released to the environment and the resulting radiation doses to members of the public living around NPPs were analyzed for the years 2011-2015 using the Korea Hydro & Nuclear Power Co., Ltd's annual summary reports of the assessment of radiological impact on the environment. The results show that tritium was the primary contributor to the activity in both gaseous and liquid effluents. The averages of effective doses to the public were approximately on the order of 10^-3 mSv or 10^-2 mSv. Therefore, even though Korean NPPs discharged some radioactive materials into the environment, all effluents were within the regulatory safety limits and the resulting doses were much less than the dose limits.

1 illus, 4 tables, 19 ref

024242   TELLILI B, ELMAHROUG Y, SOUGA C (Physics Dep, Campus Univ El-Manar, Tunis, Tunisia, Email: youssef_phy@hotmail.fr) : Investigation on radiation shielding parameters of cerrobend alloys. Nucl Eng Technol 2017, 49(8), 1758- 71.

In this study, to determine the most effective alloy for shielding against gamma-rays, the gamma-ray shielding parameters of six types of cerrobend alloys have been investigated. Gamma-ray interaction with the cerrobend alloys has been discussed mainly in terms of total mass attenuation coefficient (µ_t), half value layer (HVL), tenth value layer (TVL), effective atomic number (Z_eff), and effective electron density (N_eff). These parameters have been calculated by theoretical approach using the ParShield program in a photon energy range between 0.1 MeV and 100 GeV. The dependence of these parameters on the incident photon energy and chemical composition of the cerrobend alloys has been studied.

15 illus, 6 tables, 18 ref

024241   ZHU S, ZHANG C, YANG Z, WANG C (Tsinghua Univ, Beijing- 100 084, China, Email: chizhang@tsinghua.edu.cn) : Hydrogen's influence on reduced activation ferritic/martensitic steels' elastic properties: density functional theory combined with experiment. Nucl Eng Technol 2017, 49(8), 1748- 51.

Reduced activation ferritic/martensitic (RAFM) steels are widely applied as structural materials in the nuclear industry. To investigate hydrogen's effect on RAFM steels' elastic properties and the mechanism of that effect, a procedure of first principles simulation combined with experiment was designed. Density functional theory models were established to simulate RAFM steels' elastic status before and after hydrogen's insertion. Also, experiment was designed to measure the Young's modulus of RAFM steel samples with and without hydrogen charging. Both simulation and experiment showed that the solubility of hydrogen in RAFM steels would decrease the Young's modulus. The effect of hydrogen on RAFM steels' Young's modulus was more significant in water-quenched steels than it was in tempering steels. This indicated that defects inside martensite, considered to be hydrogen traps, could decrease the cohesive energy of the matrix and lead to a decrease of the Young's modulus after hydrogen insertion.

3 illus, 2 tables, 26 ref

024240   MULLEN E, HARRIS R, GRAHAM D, RHODES C, HODGSON Z (Engineering Design Dep, National Nuclear Laboratory, United Kingdom, Email: eve.mullen@nnl.co.uk) : Transfer characteristics of a lithium chloride-potassium chloride molten salt. Nucl Eng Technol 2017, 49(8), 1727- 32.

Pyroprocessing is an alternative method of reprocessing spent fuel, usually involving the dissolving spent fuel in a molten salt media. The National Nuclear Laboratory designed, built, and commissioned a molten salt dynamics rig to investigate the transfer characteristics of molten lithium chloride-potassium chloride eutectic salt. The efficacy and flow characteristics of a high-temperature centrifugal pump and argon gas lift were obtained for pumping the molten salt at temperatures up to 500 °C. The rig design proved suitable on an industrial scale and transfer methods appropriate for use in future molten salt systems. Corrosion within the rig was managed, and melting techniques were optimized to reduce stresses on the rig. The results obtained improve the understanding of molten salt transport dynamics, materials, and engineering design issues and support the industrialization of molten salts pyroprocessing.

7 illus, 14 ref

024239   YEON J-W, JUNG S-H (Korea Atomic Energy Research Institute, Daejeon- 34057, Republic of Korea, Email: yeonysy@kaeri.re.kr) : Effects of temperature and solution composition on evaporation of iodine as a part of estimating volatility of iodine under gamma irradiation. Nucl Eng Technol 2017, 49(8), 1689- 95.

As a part of evaluating the volatility of iodide ions subjected to gamma irradiation, I₂ evaporation experiments were performed with I₂ and I¯ mixed solutions in the temperature range 26-80 °C in an open, well-ventilated space. The evaporation of I₂ was observed to follow primarily first order kinetics, depending on the I₂ concentration. The evaporation rate constant increased rapidly with increase in temperature. The presence of I¯ slightly reduced the evaporation rate of I₂ by forming relatively stable I₃¯. The effect of Cl¯ at <1.0 wt % on I₂ evaporation was insignificant. The evaporation rate constants of I₂ were 1.3 x 10^-3 min^-1 cm^-2 , 2.4 x 10^-2 min^-1 cm^-2, and 8.6 x 10^-2 min ^-1 cm^-2, at 26 °C, 50 °C, and 80 °C, respectively.

8 illus, 33 ref

024238   ILYAS M, AYDOGAN F (Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan, Email: milyas323@gmail.com) : Steam generator performance improvements for integral small modular reactors. Nucl Eng Technol 2017, 49(8), 1669- 79.

Steam generator (SG) is one of the significant components in the nuclear steam supply system. A variety of SGs have been designed and used in nuclear reactor systems. Every SG has advantages and disadvantages. A brief account of some of the existing SG designs is presented in this study. A high surface to volume ratio of a SG is required in small modular reactors to occupy the least space. In this paper, performance improvement for SGs of integral small modular reactor is proposed. For this purpose, cross-grooved microfins have been incorporated on the inner surface of the helical tube to enhance heat transfer. The primary objective of this work is to investigate thermalehydraulic behavior of the proposed improvements through modeling in RELAP5-3D. The results are compared with helical-coiled SGs being used in IRIS (International Reactor Innovative and Secure). The results show that the tube length reduces up to 11.56 % keeping thermal and hydraulic conditions fixed. In the case of fixed size, the steam outlet temperature increases from 590.1 K to 597.0 K and the capability of power transfer from primary to secondary also increases. However, these advantages are associated with some extra pressure drop, which has to be compensated.

17 illus, 5 tables, 33 ref

024237   MAHANTHESH B, GIREESHA B J, PRASANNAKUMARA B C, SASHIKUMAR N S (Government First Grade Coll, Chikkamagaluru- 577 126, Email: dr.bcprasanna@gmail.com) : Marangoni convection radiative flow of dusty nanoliquid with exponential space dependent heat source. Nucl Eng Technol 2017, 49(8), 1660- 8.

The flow of liquids submerged with nanoparticles is of significance to industrial applications, specifically in nuclear reactors and the cooling of nuclear systems to improve energy efficiency. The application of nanofluids in water-cooled nuclear systems can result in a significant improvement of their economic performance and/or safety margins. Therefore, in this paper, Marangoni thermal convective boundary layer dusty nanoliquid flow across a flat surface in the presence of solar radiation is studied. A two phase dusty liquid model is considered. Unlike classical temperature-dependent heat source effects, an exponential space-dependent heat source aspect is considered. Stretching variables are utilized to transform the prevailing partial differential system into a nonlinear ordinary differential system, which is then solved numerically via the Runge-Kutta-Fehlberg approach coupled with a shooting technique. The roles of physical parameters are focused in momentum and heat transport distributions. Graphical illustrations are also used to consider local and average Nusselt numbers. We examined the results under both linear and quadratic variation of the surface temperature. Our simulations established that the impact of Marangoni flow is useful for an enhancement of the heat transfer rate.

12 illus, 1 table, 49 ref

024236   PILLAY A E, STEPHEN S, EIKADI M, VUKUSIC S (Chemistry Dep, Khalifa Univ of Science and Technology, Abu Dhabi, UAE, Email: apillay@pi.ac.ae) : Deep-UV ablative laser technology: A technical review. J Mater Sci 2017, 5(4), 157-64.

Ablative laser technology has been used successfully as a tool in scientific applications particularly to evaluate the homogeneity of materials and to depth-profile samples with the object of attaining elemental distribution at sub surface levels. Pulsed micro-beams strike a target with pinpoint accuracy and produce trace elemental information both spatially and in the substrate. Exploring different strata of a sample can produce data on impurities buried deep within the sample matrix. This is particularly important in cases where hidden impurities can make a difference to the performance of certain samples, such as semi-conductors or biomedical specimens. Stochastic effects such as imperfect crater formation, erratic energy pulses and unpredictable drift in beam energy could significantly affect the results of research applications. These technical features are controlled by sophisticated software, which plays a salient role in stabilizing the instrument. Samples are usually heterogeneous in nature, such as rocks, reservoir cores and concrete structures, and sample heterogeneity, therefore, is a factor that precludes adoption of conventional protocol for standardization of the technique. Soft samples such as gels and waxes could undergo standardization under special conditions. However,the technique is largely semi-quantitative for solids and is particularly attractive for exploring the homogeneity of solid targets, which reflects the level of elemental distribution within the sample matrix. The laser unit is coupled to a Perkin Elmer ICP-MS instrument and maintenance of consistent operation parameters is crucial for accurate and reproducible results. The laser beam wavelength is in the deep UV region and the system is operated with a beam of 213 nm of variable diameter between 5-100 μm, gas flow of 0.8 L/min, energy pulse rate of 60 MHz, and beam energy between 30-60%. Compared to other current instrumental techniques, ablative laser technology is superior for depth-profiling and surface analysis.

10 illus, 32 ref

024235   BADR R A (Samarra Univ, Samarrah- 340 10, Email: riyadh2824@yahoo.com) : Comparison of the effects of surface roughness of wrought aluminium alloys on the surface of steel. J Mater Sci 2017, 5(4), 149-56.

The effect of roughness of wrought aluminium alloys on the surface of steel is investigated. Roughness average (Ra) was a fixed polishing at 14 ± 0.05 μm. Also was using a pin–on disc, made of AISI 1045 steel and Ra=0.15 ± 0.05 μm, Hv=312 ± 20 kg/mm². All tests were carried out as per ASTM G-99 standard. The angular speed of the disc was a fixed 200 rpm and a load range of (5, 10, 15) N, and relative humidity 65 %. The microstructure for samples and worn surfaces were analyzed and characterized using X-ray diffraction the residual voltage (XRD), energy dispersive spectroscopy (EDS), scanning of electron microscopy (SEM) and atomic force microscopy (AFM), respectively. It was noticed that the dry sliding wear of aluminium alloys against a steel counterface resulted in severe wear for all alloys. At a load of 10 and 15 N, performs a better effect of wear resistance of A 6092 alloy and was wear reduction is 18 % comparison with A5056 and A 3003 alloys and reduce friction. However, at a heavy load of 15 N, only the pattern can effectively reduce friction. The maximum reduction rate of the average wear depth is 20 % of A 6092 alloy while a reduce 29 % and 40 % in A5056 and A3003 alloys respectively. However, there was correlation between roughness and wear rate. In all cases, a mechanically mixed layer was formed. Deformation below worn surface and wear resistance is discussed.

8 illus, 1 table, 16 ref

024234   HOWLADER R K, SHIL S K, SIKDER S S, SAHA D K (Physics Dep, Khulna Univ of Engineering & Technology, Khulna, Bangladesh, Email: sujitphy.kuet@gmail.com) : Effect of annealing temperature on the complex permeability of (Fe_0.95Co_0.05)_73.5Cu₁N b₃Si_13.5B₉ nanocrystalline amorphous ribbon. J Mater Sci 2017, 5(4), 144-8.

FINEMET-like amorphous ribbon of composition (Fe_0.95Co_0.05)_73.5Cu₁N b₃Si_13.5B₉ was prepared by rapid quenching method in an Argon (Ar) atmosphere. The alloy has been annealed in a controlled way in the temperature range of 550 to 750 °C for 30 minutes. Nanocrystalline state was evaluated by X-ray diffraction (XRD). In the range of annealing temperature (Ta), the grain size has been found in the range of 9-26 nm. Frequency dependence of permeability of amorphous and nanocrystalline toroid shaped samples have been measured. The low frequency initial permeability for the optimum annealed samples has been found to 5.8 × 103 and the highest value of quality factor is found for the sample annealed at 550 °C; which also indicates the best heat treatment temperature.

5 illus, 1 table, 17 ref

024233   OTHMAN M (General Science Dep, Soran Univ, Soran-Erbil, Iraq, Email: mazin.othman@soran.edu.iq) : Modeling pressure dependent elastic parameters of GaAsSb Alloy. J Mater Sci 2017, 5(4), 112-9.

Density functional theory with GGA approximation elastic properties of GaAs_1-xSb_x of x=0.5 have been calculated from 0-20 GPa range of pressure. The geometry adjusted structural parameters for GaAs_1-xSb_x under separate pressures and they are listed. It was detected that lattice constant decreased by pressure increasing. Furthermore, parameter B decreased and parameter S and Y increased by pressure increasing. The elastic constants fulfilled the customary mechanical stability conditions for the ternary intermingled crystals. The elastic modulus was gained. The adjusted elastic constants varied with various rates under increasing pressure.

5 illus, 3 tables, 25 ref

024232   CHEN X, YAN-HUI L , YONG-QUAN N (Shaanxi Univ of Science & Technology, Xian- 710 021, China, Email: lyanhuiedu@163.com) : A new piecewise dynamic constitutive equation of powder metallurgy high speed steel. J Mater Sci 2017, 5(4), 100-11.

In order to optimize the hot working technology of powder metallurgy high speed steel, the hot deformation behavior of powder metallurgy (PM) high speed steel was investigated by Gleeble-1500D simulation at the temperature range of 1000-1150 °C, strain rates between 0.001 s^-1 and 1.0 s^-1 and deformation rate of 60 % of the samples. The flow stress under different temperatures and strain rates were analyzed. The results show that the flow stress is influenced strikingly by deformation temperature and strain rate. Both the peak stress and the corresponding strain decrease with the increase of temperature and the decrease of strain rate. Deformation temperature, strain rate and deformation activation energy have a great affect on the microstructure. The value of deformation activation energy is 750.67 kJ/mol. The mathematical model of the strain corresponding to the peak stress was set up. The relationship between the strain corresponding to the peak stress and the strain corresponding to the critical stress can be described as: εc=0.606 εp. The segmental dynamic constitutive equation under different strain was established based on the idea of subsection.

11 illus, 2 tables, 24 ref

024231   ZHANG S, LI T, ZHANG G, FENG Y (Tokai Univ, Kanagawa 259-1292, Japan, Email: zhangs@tsc.u-tokai.ac.jp) : Comparison of sequential light, scanning electron and atomic force examine methods for electron beam lithography generated patterns. J Mater Sci 2017, 5(4), 76-82.

Super elliptical plates which are defined by shapes between an ellipse and a rectangle have a wide range of use in engineering applications. Investigations on non-linear behaviors of super elliptical isotropic plates are available in the literature, while investigations on nonlinear behaviors of FGM super elliptical plates haven’t been reported at present. In this paper, nonlinear bending and thermal post-buckling analysis are first presented for functionally graded super elliptical plates based on classical plate theory. Material properties are assumed to be temperature-dependent and graded in the thickness direction. The numerical illustrations concern the nonlinear behaviors of functional graded plates with immovable simply supported edge and immovable clamped edge. Influences played by different supported boundaries, thermal environmental conditions, and volume fraction index are discussed in detail using Ritz method.

5 illus, 3 tables, 9 ref

024230   ZHANG D-G (China Jiliang Univ, Hangzhou- 310 018, Email: smzhangdaguang2012@gmail.com) : Nonlinear bending and thermal post-buckling analysis of FGM super elliptical thin plates. J Mater Sci 2017, 5(4), 66-75.

Super elliptical plates which are defined by shapes between an ellipse and a rectangle have a wide range of use in engineering applications. Investigations on non-linear behaviors of super elliptical isotropic plates are available in the literature, while investigations on nonlinear behaviors of FGM super elliptical plates haven’t been reported at present. In this paper, nonlinear bending and thermal post-buckling analysis are first presented for functionally graded super elliptical plates based on classical plate theory. Material properties are assumed to be temperature-dependent and graded in the thickness direction. The numerical illustrations concern the nonlinear behaviors of functional graded plates with immovable simply supported edge and immovable clamped edge. Influences played by different supported boundaries, thermal environmental conditions, and volume fraction index are discussed in detail using Ritz method.

11 illus, 1 table, 22 ref

024229   SRI MAHA VISHNU D, SUNIL N, MOHANDAS K S (Indira Gandhi Centre for Atomic Research, Kalpakkam- 603 102, Email: smvd2@cam.ac.uk) : Difference in the mechanism of electrochemical deoxidation of conducting and non-conducting solid oxide preforms: An experimental demonstration with TiO₂ and SiO₂ Pellet Electrodes in CaCl₂ melt. J Mater Sci 2017, 5(4), 55-65.

Powder compacted and sintered solid oxide preforms, generally shaped as thin pellets, have been used as the negative electrode of a molten salt electro-deoxidation cell and deoxidation of the electrode is greatly influenced by its electrical conductivity. The deoxidation pattern of electron conducting and non-conducting oxide preforms should,therefore, be different. In order to demonstrate this experimentally, novel electrochemical experiments were carried out with electron conducting TiO₂ and non-conducting SiO₂ pellet electrodes in calcium chloride melt at 1173 K. The experimental results have shown, as already reported by many previously, that three physically distinct phases, viz. the solid electron conductor, the oxide and the electrolyte melt should coexist for electro-deoxidation of non-conducting SiO₂ electrode but only two physically distinct phases, viz. the oxide and the electrolyte melt need only to coexist in the case of conducting TiO₂ electrode. It is demonstrated in this study, for the first time, that the 3 Phase Interline (3PI) mechanism, proposed to explain electro-deoxidation of solid oxides in general, stands reduced to 2 Phase Interface (2 PI) mechanismin the case of conducting oxides.

10 illus, 38 ref

024228   KHAN S B, WU H, PAN C, ZHANG Z (Tsinghua Univ, Beijing- 100 084, China, Email: zjzhang@tsinghua.edu.cn) : A mini review: Antireflective coatings processing techniques, applications and future perspective. J Mater Sci 2017, 5(4), 36-54.

Antireflective coatings (AR) are widely applied to eliminate the unwanted surface reflections from the AR coated substrate. In different optoelectronic devices, AR coatings have potential usage in photovoltaic solar cells, sensors, display devices, automobile industries to reduce reflectance, glare and enhance light transmittance. Natural phenomenon inspires researchers, and they generate bionic AR coatings copying the nature such as moth eyes, orcicada wings to fabricate efficient light harvesting AR coatings. In the current review article, we analyse and evaluate critically the progress and recent development in the fabrication of AR thin films comprising organic coatings, inorganic coatings, polymer AR coatings and bionic AR coatings. We predominantly emphasise the AR coatings fabrication by different methods and pinpoints the technological challenges in their real-world reliability. Finally, we address the future challenges and potential strategies for their upcoming prospect.

8 illus, 166 ref

024227   GUPTA M, DAS A, SUBRAMANIAN S (Biotechnology Dep, VIT Univ, Vellore- 643 014, Email: sangeethasubramanian@vit.ac.in) : A mini review on application of TiO₂ nanoparticle in wool technology. J Ind Pollut Control 2017, 33(2), 1633- 8.

In recent years attention has been towards the development of smart textiles with superior characteristics and enhanced durability. To cater the needs of high sustainable textiles, application of nanotechnology has been introduced in textile industry with promising achievement. Titanium oxide nanoparticle is one such material which could be applicable in textile industry, whose photo-catalytic activities have been widely investigated owning to its high stability and low toxicity. This paper enlists various applicative properties of titanium oxide nanoparticles and its implementation in the textile industry, especially to woollen fibres for advanced applications.

2 illus, 2 tables, 47 ref

024226   KUMAR S B S, MCHINNAPANDIAN (Aeronautical Engineering Dep, St. Peter’s Coll of Engineering and Technology, Chennai- 600 054, Email: sbs.kumar@yahoo.com) : Review on comparison of different solar techniques and thermal storage system. J Ind Pollut Control 2017, 33(2), 1098- 1105.

In developing world, the energy requirement is very high, to execute the demands for future need of energy, the renewable sources are to be needed. As usage of fossil fuel is increased day by day and it pollutes the environment. There is an alternate energy source is required it should be protect the environment from the pollutants and also to produce cost-effective. Solar is the best energy source which accomplishes energy requirements with the eco-friendly nature. The parabolic trough collector (PTC) using phase change materials (PCMs) absorbs the solar energy and delivers constant heat to the cooking vessel which have been attempted by experimental model analysis. This review is confined to the enhancement of a PTC is utilized as the source of heat and TES (Thermal storage system) and PCMs for intermediate energy storage. The review covers different solar techniques and TES and tracking system.

4 illus, 30 ref

024225   SINGH B, PORWAL S (Sri Radhey Lal Arya Inter Coll, Hathras, Email: saurabhjcb@rediffmail.com) : Generalized convolution of certain class of harmonic univalent functions. J Ultra Scient Phys Sci 2018, 30(1), 1 - 7.

The purpose of the present paper is to establish some results generalized convolution for a subclass of harmonic univalent functions.

18 ref

024224   WANG S, XIANG W, FAN H, XIE J, QIAN Y-F (Shanghai Ocean Univ, Pudong- 201 306, Email: jxie@shou.edu.cn) : Study on the mobility of water and its correlation with the spoilage process of salmon (Salmo solar) stored at 0 and 4?C by low-field nuclear magnetic resonance (LF NMR1H). J Fd Sci Technol 2018, 55(1), 173- 82.

Low-field nuclear magnetic resonance (LFNMR) was used to investigate the water mobility of salmon during cold storage and the correlation between texture, freshness, sensory quality and transversal relaxation times (T₂) of salmon were studied. With the increasing of cold storage time, trapped water (T₂₂), sensory, water holding capacity and cooking loss were descended while free water (T₂₃), TVB-N and TBA were increased steadily, that reflected the quality of salmon quality visually. There was a significant correlation between sensory, hardness, TBA, cooking loss, K value and LF NMR parameters. The study showed that LF NMR was sensitive to different storage conditions which may be applied to monitor the quality of fish muscle, when the spoilage mechanism was affected by water properties and muscle structure.

4 illus, 2 tables, 40 ref

024223   RAMOLA Y, LOUIS C N, AMALRAJ A (Holy Cross Coll, Tamil Nadu) : High pressure electronic phase transition, metallization and superconductivity in Rbl. Int J Chem Sci 2018, 2(1), 36- 41.

The electronic phase transition, metallization and superconducting transition of the simple alkali iodide Rubidium Iodide (Rbl) is investigated through their band structure. The self-consistent band structure calculation is performed both in NaCl and CsCl structures using the full potential linear muffin-tin oRbltal (FP-LMTO) method. The equilibrium lattice constant, bulk modulus and the phase transition pressure at which the compound undergoes structural phase transition from NaCl to CsCl are predicted from the total energy calculations. The band structure, density of states (DOS), electronic charge distributions, metallization and superconducting transition temperature (Tc) of Rbl are obtained as a function of pressure for both in NaCl and CsCl structures. The density of states at the Fermi level (N(EF)) gets enhanced under pressure, which leads to metallization in Rbl. It is found that, the charge transferfroms and p states to d state causes structural phase transition and superconductivity in Rbl. The pressure corresponding to structural phase transition from NaCl structure (B1) to the CsCl structure (B2) is 0.021 Mbar in Rbl. This value is agreement with the experimental value of 0.02 Mbar. In Rbl, the metallization occurs through indirect closing of the band gap between Γ and H points at the reduced volume V/Vo=0.43 (CsCl structure), the corresponding metallization pressure is 1.228 Mbar. Our results completely agree with the experimental observation of 1.31 Mbar. The highest Tc estimated is 2.151 K and the corresponding pressure is 4.945 Mbar in the NaCl structure and 0.107 K in the CsCl structure.

4 illus, 5 tables, 33 ref

024222   PALODIYA V, RAGHUWANSHI S K (Electronics and Communication Engineering Dep, Sphoorthy Engineering Coll, Hyderabad- 501 510, Email: vikrampalodiya@gmail.com) : Dispersion characteristics of novel class multi-clad dispersion shifted hollow core fibers for WDM optical systems. Indian J Pure Appl Phy 2018, 56(1), 76- 9.

The design and analysis of multiple-clad hollow core dispersion-shifted fibers have been presented in this paper. Fiber profiles have been designed consisting of a central core that is hollow and outer cladding is silica. The novel refractive index profile has multi-clad for enhanced optical characteristics. Optical fibers with two or more claddings are required for dispersion shifting, dispersion flattening, and other specialized applications. Thus, the hollow core fiber shows the zero dispersion at 1550 nm wavelength. These hollow core fibers have potential application in WDM optical systems.

3 illus, 19 ref

024221   SINGH S, SINGH V, GUPTA A (CSIR-National Physical Laboratory, New Delhi- 110 012, Email: sukhvirster@gmail.com) : Investigations of structural, chemical and physical properties of natural lac and its reinforced composites. Indian J Pure Appl Phy 2018, 56(1), 69- 75.

Natural lac resin is secreted by the small parasitic insect Kerria Lacca on various host trees in India. It has been conventionally used as filling, protective, adhesive, binder and insulating material. Cultivated by tribal people for various applications, the earliest popularly known reference to its use is found in the Mahabharata epic. Because of the imminent danger of environmental degradation, mankind is now veering towards a refreshing global awareness of the need to use, natural products because of their organic, non-toxic and biodegradable nature. This way, the present study is focused to understand the physical, structural and chemical properties of these natural lac and its applied form chapadi (a mixture of lac and sand), which has been used, for more than 500 years, as an adhesive and filling material by traditional Swordsmiths in Rajasthan (India). In addition, new lac-based composites reinforced with carbon nanotubes and carbon fibres have been synthesised and studied for their structural and physical properties. Surface morphology and elemental composition of as synthesized samples have been carried out by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). FTIR spectra have been recorded in order to identify the organic functional group. Samples of CNTs and carbon fibre reinforced with pure lac have been found to be better adhesives. The study aims to understand the nature of these reinforced composites as a new material that can be used for various applications in future.

12 illus, 1 table 17 ref

024220   JHANLKAL A K (Indian Military Academy, Dehradun- 248 007, Email: anujjhankal@yahoo.com) : Application of homotopy perturbation method for MHD free convection of water at 4 ?C through porous medium bounded by a moving vertical plate. Indian J Pure Appl Phy 2018, 56(1), 63- 8.

An analysis has been made to study the problem of two-dimensional magnetohydrodynamic (MHD) free convection of water at 4 ºC through porous medium bounded by a moving vertical plate. The governing partial differential equations have been transformed into self-similar ordinary differential equations using similarity transformations before being solved by He’s homotopy perturbation method (HPM). The main advantage of HPM is that it does not require the small parameters in the equations and hence the limitations of traditional perturbation can be eliminated. The results reveal that the proposed method is very effective and simple and can be applied to other nonlinear problems. A parametric study of all involved physical parameters has been conducted and a representative set of numerical results for the velocity, temperature and skin-friction has been illustrated graphically. Physical aspects of the problem have also been discussed.

4 illus, 37 ref

024219   VANDANA S, BENNY P G, SELVAM T P (Radiological Physics & Advisory Division, Bhabha Atomic Research Centre, Mumbai- 400 085, Email: bikaiv_barc@rediffmail.com) : Comparison of measured and Monte Carlo-calculated electron depth dose distributions in aluminium. Indian J Pure Appl Phy 2018, 56(1), 48- 52.

Depth dose profiles in aluminium have been measured using the cellulose triacetate dosimeter against different electron energies (4, 4.5 and 5 MeV) at a recently upgraded 15 kW industrial electron beam accelerator facility. The study also includes comparison of these profiles against Monte Carlo calculations. The measured and simulated depth dose profiles are similar in shape. For all electron energies, at initial depths, the measured doses are higher than the simulated ones. The simulated and measured normalized surface dose values are 0.58 and 0.66, respectively, independent of electron energy. The difference in the surface dose between Monte Carlo and experiment could be attributed to possible presence of low energy electrons in the measurements whereas the Monte Carlo calculations are based on monoenergetic electrons. Between the region of dose maximum and the tail portion of the depth dose curve, the measured dose is smaller than the simulated values (about 17 % to 40 % at 5 MeV). Using the depth dose profiles, electron beam parameters such as depth at which maximum dose occurs, d_max , practical range, R_p and half-value depth, R₅₀ have been determined. Using the measured parameters R_p and R₅₀ , the incident kinetic energy of the electron beam has been determined. The estimated electron energies while using R_p are 4.02, 4.41 and 4.75 MeV. When using R₅₀ , the corresponding values are 3.83, 4.21 and 4.64 MeV. The measured RP/R₅₀ ratios are slightly larger than the Monte Carlo-calculated values, which suggest that the electron beam may not be monoenergetic.

5 illus, 4 tables, 17 ref

024218   MANTHRI S A, MUHAMED R R, RAJESH R, SATYANARAYANAMOORTHI V (Physics Dep, PSG Coll of Arts and Science, Coimbatore- 641 014, Email: sathyanarayanamoorthi@yahoo.co.in) : Spectroscopic and quantum mechanical investigations of (2E)-3-(2H-1,3-benzodioxol-5-yl)-N-phenylprop-2-enamide using density functional theory method. Indian J Pure Appl Phy 2018, 56(1), 34- 47.

The Fourier transform infrared (FTIR) and FT-Raman of (2E)-3-(2H-1,3-benzodioxol-5-yl)-N-phenylprop- 2-enamide (2BNP2E) have been recorded in the regions 4000-100 and 4000-450 cm^-1, respectively. A complete assignment and analysis of the fundamental vibrational modes of the molecule have been carried out. The observed fundamental modes have been compared with the harmonic vibrational frequencies computed using DFT (B3LYP) method by employing 6-311++G(d,p) basis set. The vibrational studies have been interpreted in terms of potential energy distribution. The first order hyperpolarizability (β0) and related properties (α, μ and ∆α) of this molecular system are calculated using B3LYP/6-311++G(d,p) method based on the finite-field approach. Stability of the molecule arising from hyperconjugative interactions and charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The results show that electron density (ED) in the σ* and π* anti-bonding orbitals and second-order delocalization energies (E(2)) confirm the occurrence of intramolecular charge transfer (ICT) within the molecule. Molecular electrostatic potential (MEP) and HOMO-LUMO energy levels have also been constructed. The thermodynamic properties of the title compound have been calculated at different temperature and the results reveal that the standard heat capacity c° pm, entropy Som and enthalpy changes H°m increase with rise in temperature.

7 illus, 6 tables, 48 ref

024217   RAVI M, BHAT K S (Defence Research & Development Organization, Bangalore- 560 093, Email: mravi@mtrdc.drdo.in) : Studies on triple junction electric field in ferroelectric cathodes. Indian J Pure Appl Phy 2018, 56(1), 26- 33.

To investigate the effect of grid thickness and dielectric constant on the ferroelectric cathode triple junction electric field distribution in a two-dimensional structure, simulation has been carried out using finite element method (FEM) code ANSYS. Triple junction electric field plays a major role in the emission of electrons from a ferroelectric cathode and it approaches towards its limiting value even if the dielectric constant of the ferroelectric material is increased considerably. It is important to increase the triple junction electric field without increasing the applied field to reduce the mechanical stresses in the ferroelectric material. A dielectric layer (εr < 100) has been introduced between the ferroelectric material and the grid to increase the triple junction electric field. FEM simulation results showed that the triple junction electric field is more than 48 times the applied field in this case. This structure not only enhances the triple junction electric field but it also changes the E|| and E┴ ratio (β) favorably. Effects of dielectric constant and the thickness of the dielectric layer on triple junction electric field have been studied.

13 illus, 20 ref

024216   AROTE S A, TABHANE V A (Physics Dep, D J M Commerce and B N S Science Coll, Ahmednagar- 422 605, Email: sandeeparote@gmail.com) : Studies on single step facile growth of different tin oxide nanostructures at room temperature. Indian J Pure Appl Phy 2018, 56(1), 7 - 12.

Herein, tin oxide (SnO and SnO₂) nanostructures in the form of granules, microsheets and their self-assembled flower-like morphology have been reported. The samples have been prepared by a simple single step chemical route at room temperature on a large scale. The crystalline phase, microstructural and optical properties of the nanostructures have been characterized by X-ray powder diffraction, scanning electron microscopy and UV-Vis spectroscopy. The effects of precursor concentration and reaction route on the structural, morphological and optical properties of the as synthesized sample have been investigated. The phase transition from crystalline tetragonal phases of SnO to SnO₂ has been observed as an effect of variation in NaOH concentration. The optical band gap of material has been found to be 3.05 and 3.64 eV for SnO and SnO₂, respectively. The isolated porous microspheres of SnO with diameters ranging from 12-15 μm have been observed. The growth mechanism of different morphologies has been discussed.

4 illus, 1 table, 37 ref

024215   SINGH G P, SOHI B S, RAJ B (Electronics and Communication Dep, Chandigarh Univ, Mohali- 140 413, Email: gurinder.pal@cumail.in) : Material properties analysis of graphene base transistor (GBT) for VLSI analog circuits design. Indian J Pure Appl Phy 2017, 55(12), 896- 902.

Graphene base transistor’s (GBT) analysis has been reviewed in this paper. This study has been focused on work carried out by other authors for GBT physics. Here prominence has been given to material properties and their effects on GBT for VLSI analog circuit design to operate in high frequency range of THz. Various papers in literature have been reported for the implementation of designs with different emitter and collector materials. Materials properties are the controlling parameters to decide cut-off frequency (f_T), trans-conductance, gain and off current (I_off) in GBT. The implemented results of literatures signify that the electron affinity and work function of emitter and collector are the dominant factors for flow of charges from emitter to collector. Dependency of these two parameters on dielectric constant and thickness of emitter-base insulator (EBI) and base collector insulator (BCI) that are tantalum pentoxide (Ta₂O₅), carbon-doped silicon oxide (SiCOH) and SiO₂ has been studied. Effects of collector and BCI thickness have been investigated in detail to scrutinize base leakage current by the virtue of back scattering in collector-BCI interface. Small signal equivalent circuit model for GBT have also been studied by including parasitic capacitance behaviour between graphene Dirac-point potential with respect to graphene fermi level, emitter, EBI, BCI and collector fermi level potential.

8 illus, 23 ref

024214   RANI A, SINGH Y P (CSIR-National Physical Laboratory, New Delhi-110 012, Email: yeshsingh1956@gmail.com) : Investigation of fixed point of copper in the metal-in-graphite blackbody cavity using standard photoelectric linear pyrometer. Indian J Pure Appl Phy 2017, 55(12), 857- 63.

The phase transition temperature of high purity copper has been used as fixed point temperature to calibrate standard thermometers of both contact as well as non-contact type. In the present work the freezing point of copper has been measured by a spectral radiation pyrometer using copper-in-graphite black body crucible fabricated in the form of a cavity with an aperture of 10 mm. A recently procured detector based photoelectric pyrometer, LP4 has been used as transfer standard in the measurement process. The output signal of photocurrent due to radiation from the source of copper blackbody cavityat wavelength of 650 nm in vacuum has been measured during the period when metal changes its phase from solid to liquid and liquid to solid. The stability of fixed point has been determined from the melting and freezing curves plotted between the photocurrent or corresponding temperature and the time period of the whole cycle. The uncertainty in the measurement of copper point has been evaluated to be ± 0.530 ºC and thus the copper freezing point has been determined to be 1083.41 ºC (± 0.53 ºC, at k =2) differing from the assigned value in the international temperature scale of 1990 (ITS-90) by 1.21 ºC lower while the melting point of copper has been determined to be 1084.23 °C differing by 0.39 °C lower respectively than the defined value of ITS-90.

8 illus, 1 table, 20 ref

024213   JHANKAL A K (Indian Military Academy, Dehradun-248 007, Email: anujjhankal@yahoo.com) : MHD boundary layer flow and heat transfer along an infinite porous hot horizontal continuous moving plate. Indian J Chem Technol 2018, 25(1), 106-10.

Analysis is to study the two-dimensional magnetohydrodynamic (MHD) boundary layer flow and heat transfer along an infinite porous hot horizontal continuous moving plate. The governing partial differential equations are transformed into self-similar ordinary differential equations using similarity transformations before being solved analytically. Numerical results for the dimensionless velocity profiles, the temperature profiles, the skin friction coefficient and the Nusselt number are present graphically and discuss briefly for various physical parameters, such as magnetic parameter M, plate velocity α, Prandtl number Pr, Eckert number Ec and heat source/sink parameter S. It has been found that these parameters have significantly effects on the flow and heat transfer.

8 illus, 23 ref

024212   RAO K V, RAO S, REVATHI A, DAYANANDA G N (CSIR-National Aerospace Laboratories, Bangalore 17, Email: rao_kavi@nal.res.in) : Influence of soft segments on thermo-mechanical behaviour of novel epoxy based shape memory polymers. Indian J Chem Technol 2018, 25(1), 68-73.

Epoxy based Shape Memory Polymers (SMEPs) have been formulated by reacting an aerospace grade aromatic epoxy resin with aliphatic amines. TETA (triethylenetetramine) series and TTD (trioxatridecanediamine) series SMEPs with varying soft segment contents and with glass transition temperatures (Tgs) ranging from 103-51°C have been obtained. The viscoelastic behaviour of SMEPs has been investigated using an Advanced Rheometric Expansion System (ARES). For the thermomechanical tests, the respective Tg of each SMEP has been fixed as the deformation as well as recovery temperature (shape switching temperature). Further, the effect of soft segments on thermo-mechanical shape memory behaviour of the SMEPs has been evaluated. The results reveal that TTD series SMEP with maximum soft-segment content exhibit a narrow viscoelastic region, complete shape recovery and very good shape memory behaviour. Thus based on specific applications the soft segment content may be varied suitably.

7 illus, 5 tables, 21 ref

024211   CHOUDHARY S (Physics Dep, Jai Narain Vyas Univ, Jodhpur- 342 005, Email: shobhnachoudhary@rediffmail.com) : Influence of Al₂O₃ nanoparticles on the dielectric properties and structural dynamics of PVA-PEO blend based nanocomposites. Indian J Chem Technol 2018, 25(1), 51-60.

The organic-inorganic nanocomposite films comprising poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO) blend matrix dispersed with alumina (Al₂O₃) nanoparticles (i.e., (PVA-PEO)–xwt % Al₂O₃; x = 0, 1, 3 or 5) have been prepared by the solution-cast method. The X-ray diffraction study confirms a large decrease in crystalline phase of the PVA-PEO blend structures with the addition of 1 wt % Al₂O₃, and it decreases gradually with the further increase of Al₂O₃ contents. Influence of Al₂O₃ nanofiller on the complex dielectric permittivity, electrical conductivity, electric modulus and the impedance properties of these polymer nanocomposite (PNC) films have been investigated over the frequency range from 20 Hz to 1 MHz by employing the dielectric relaxation spectroscopy (DRS). The ambient temperature dielectric permittivity values of the PNC films decrease initially up to 3 wt % Al₂O₃ loading in the PVA-PEO blend matrix, whereas for 5 wt % Al₂O₃, it again increases and exceeds the value of pristine polymer blend film.The relaxation processes exhibited in the dielectric loss tangent and the loss part of electric modulus spectra reveal that the polymers cooperative chain segmental motion enhances in the presence of Al₂O₃ nanoparticles in the PVA-PEO blend structures. Further, it has been found that the values of dielectric permittivity increase whereas the relaxation time decreases with the increase of temperature of the (PVA-PEO)–3 wt % Al₂O₃ film from 27 to 60 °C. The dielectric and electrical parameters of the PNC films have been analyzed in regards to their suitability as flexible-type novel nanodielectric material for the electrical insulation, the dielectric substrate in the fabrication of high performance organic microelectronic devices, and also in the preparation of nanocomposite solid polymer electrolytes (NSPEs) for the energy storing devices.

11 illus, 1 table, 66 ref

024210   HEDGE A V, MOHAN S, PINHO J L S, SHARHABEEL P S (Applied Mechanics and Hydraulics Dep, National Institute of Technology, Karnataka- 575 025, Email: arkalvittal@gmail.com) : Physical model studies on the stability of emerged seaside perforated semicircular breakwaters. Indian J Geo-Mar Sci 2018, 47(03), 681-5.

Present study discusses experiments conducted in a two dimensional monochromatic wave flume to determine the critical (minimum) weight required to resist the sliding of an emerged seaside perforated semicircular breakwater model. It is observed from a detailed review that there is hardly any literature, stressing the critical weight determination for the sliding stability of this breakwater type. Hence, the present research was taken up to study the variations in the critical weight required for sliding stability with different wave and structural specific parameters. The variations were recorded graphically using non-dimensional parameters obtained from a dimensional analysis using Buckingham’s π theorem.

4 illus, 2 tables, 16 ref

024209   RANI C S, THANGARAJ G, SURESH D M, JOHN N J (Physics Dep, Noorul Islam Univ, Tamil Nadu-629 180, Email: sagirani.c@gmail.com) : Influence of ball milling on CdO nanoparticles prepared by thermal decomposition. Oriental J Chem 2018, 34(1), 568-72.

Cadmium oxide has found its applications in various areas of research such as solar cells, phototransistors, photodiodes, transparent electrodes and gas sensors. In the present work CdO nano particles were successfully synthesized from cadmium acetate through thermal decomposition at high temperatures by adopting the solid state reaction. The prepared nano particles are subjected to ball milling for different timings. From X-ray diffraction it was found that the particle size decreases for an increase in the time of ball milling. The structure and the elemental composition were analyzed using SEM with EDAX. The optical band gap of CdO nano particles were determined using UV-Vis absorption spectroscopy. The thermal properties were determined using TGA/DTA analysis.

4 illus, 22 ref

024208   BHAGYALAKSHMI P, RAJAN K, KUMAR K R S (St.Peter’s Univ, Tamil Nadu- 600 054, Email: bhagyalv6@gmail.com) : Experimental study on solar energy storage using phase change materials in spherical shell storage system. Oriental J Chem 2018, 34(1), 507-12.

Storing of available energy for later use is a necessity in the present world, one such method is using Phase Change Materials (PCMs). PCMs need a heat transfer medium to transfer the energy from the source to the PCM. In this present work spherical balls are used to store the PCM and water is used as a heat transfer fluid. Paraffin wax (PW) and Palmitic acid (PA) and (40- 60 % PW-PA) eutectic mixture are used as PCMs. The solidification process is carried out in three different ways as cold water, hot water and natural solidification without water. In case of hot water and natural solidification processes the three materials posses the stable reduction. In cold water solidification process base materials have sudden drop in temperature where as the eutectic mixture has gradual change.

6 illus, 2 tables, 21 ref

024207   EFIMOV A A, ARSENOV P V, MAEDER T, IVANOV V V (Physical and Quantum Electronics Dep, Moscow Institute of Physics and Technology, Dolgoprudny- 141 701, Email: efimov.aa@mipt.ru.) : Unipolar charging of aerosol particles in the size range of 75-500 nm by Needle-plate corona charger. Oriental J Chem 2018, 34(1), 214-21.

A simple unipolar needle-plate corona charger (NPC) was designed, fabricated and tested on aerosol Al2O3 particles in the size range 75-500 nm. The intrinsic charging efficiency, particle electrostatic losses, and extrinsic charging efficiency were investigated depending on the corona current (35-215 μA), corona polarity, and aerosol flow rate (12-250 l/min). It was found that the intrinsic charging efficiency of the NPC is growing with increase in the corona current and the particle size and decrease in the aerosol flow rate. However, the extrinsic charging efficiency is lower than intrinsic one due to the particle electrostatic losses. Although the NPC has very simple design, it provides the extrinsic charging efficiency comparable with that of unipolar corona chargers of other types having more complicated design. The maximum value of the extrinsic charging efficiency was more than 40 % for particles in the size range from 98 to 210 nm.

6 illus, 20 ref

024206   VARFOLOMEEV A, SOLOVEY V, VOLKOV I, MAEDER T (Moscow Institute of Physics and Technology, Moscow, Russia, Email: volkov256@yandex.ru) : Synthesis and investigation of electrical properties of carbon nanotube ? Porous matrix composites near the percolation threshold. Oriental J Chem 2018, 34(1), 24 - 9.

The composites based on single-walled carbon nanotubes (single-walled CNTs or SWCNTs) embedded in porous matrices with different structures were prepared and studied by using the impedance spectroscopy. The contributions of intra-CNT and inter-CNT conduction mechanisms in the composites were evaluated at various contents of SWCNTs from the analysis of their impedance spectra. The electrical percolation thresholds for the composites studied were determined by taking into account the tunneling through the potential barriers between SWCNTs.

6 illus, 9 ref

024205   LIU YI, LI M, ZHAO P, WANG X, QU S (Physics Dep, Harbin Institute of Technology, Harbin-150 001, People’s Republic of China, Email: slqu@hit.edu.cn) : High sensitive temperature sensor based on a polymer waveguide integrated in an optical fibre micro-cavity. J Optics 2018, 20(1), 15801.

A Mach–Zehnder interferometer (MZI) based on a polymer waveguide integrated in an optical fibre micro-cavity was proposed. The micro-cavity with two symmetric openings was fabricated in single mode fibre by using femtosecond laser micromachining and fibre splicing. Then, the polymer waveguide with a length of 70 μm was integrated into the micro-cavity by using a twophoton polymerization fabrication method. The MZI exhibited a perfect interference spectrum with a fringe visibility of almost 25 dB. Owing to the high thermo-optical coefficient of the polymer material, the temperature sensitivity of the proposed MZI reached 447 pm/°C. Meanwhile, it can be used as a reliable temperature sensor as its perfect linearity (99.7 %) and repeatability.

5 illus, 27 ref

024204   ANCHAL A (Applied Physics Dep, The Hebrew Univ of Jerusalem, Jerusalem, Israel, Email: anchaliitk@gmail.com) : A novel method of sourceless continuous wave laser for fiber-to-the-home application. J Optics 2018, 20(1), 15705.

We propose a novel scheme of a sourceless continuous wave laser using a broadening of an optical pulse in a highly dispersive medium. The optical pulse is converted to a continuous wave (CW) by passing it through the highly dispersive medium in a loop. The broadening of the pulse is accompanied with a delay in dispersive medium, which restricts the repetition rate of the pulse being converted into continuous wave. We present the expression of flatness achieved in the conversion process for Gaussian pulse. Flatness of the CW laser depends upon the dispersion parameter, number of passes and the delay provided by the dispersive medium. We present a comparative study of the photonic crystal fiber, standard single mode fiber and optical waveguide as the dispersive elements. We study the effects of pulse width, repetition rate, number of passes through dispersive element and operating wavelength on flatness. Simulation results confirm the generation of CW laser with 90 dB flatness obtained at 100 GHz repetition rate of input pulse with a photonic crystal fiber.

9 illus, 25 ref

024203   HUANG S, WANG W, ZENG J, YAN C, LIN Y, WANG T (Shanghai Univ, Shanghai- 200 072, People’s Republic of China, Email: sjhuang@shu.edu.cn) : Measurement of the refractive index of solutions based on digital holographic microscopy. J Optics 2018, 20(1), 15704.

A new approach for the refractive index (RI) measurement of solutions is proposed based on digital holographic microscopy. The experimental system consists of a modified Mach–Zehnder interferometer and related lab-developed analysis software. The high quality digital hologram of the tested solution is obtained by the real-time analysis software, which is firstly encapsulated into a capillary tube, and then the capillary tube is inserted in a matching fluid. An angular spectrum algorithm is adopted to extract the phase distribution from the hologram recorded by a CCD. Based on a capillary multi-layer calculation model, the RI of the tested solution is obtained at high accuracy. The results of transparent glycerol solution measured by the proposed method are more accurate than those measured by the Abbe refractometer. We also measure the RI of translucent magnetic fluid, which is not suitable to be measured by the Abbe refractometer. The relationship between the RI and the concentration of magnetic fluid is experimentally studied, and the results show that the RI is linearly related to the concentration of dilute magnetic fluid.

6 illus, 2 tables, 26 ref

024202   GHORAI A, WALVEKAR P, NAYAK S, NARAYAN K S (Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru- 560 064, Email: narayan@jncasr.ac.in) : Influence of non-line of sight luminescent emitters in visible light communication systems. J Optics 2018, 20(1), 15703.

We introduce and demonstrate concepts which utilize the non-line of sight fraction of light incident on a detector assembly in a visible-light communication (VLC) system. In addition to ambient light, realistic enclosures where VLC is implemented consist of a sizable fraction of scattered and reflected light. We present results of VLC systems with detectors responding to contributions from the light source scattered off a surface embedded with fluorescent and phosphorescent emitters besides the direct line of sight signal. Contribution from the emitters takes a form of discernible fluctuations in the detector signal. The implication of our results from noise analysis of these fluctuations indicates the possibility of utilizing smart coatings to further tailor VLC capabilities.

5 illus, 34 ref

024201   KUMAR R, BHADURI B, NISCHAL N K (Applied Physics Dep, Indian Institute of Technology, Jharkhand 826 004, Email: basanta@iitism.ac.in) : Nonlinear QR code based optical image encryption using spiral phase transform, equal modulus decomposition and singular value decomposition. J Optics 2018, 20(1), 15701.

In this study, we propose a quick response (QR) code based nonlinear optical image encryption technique using spiral phase transform (SPT), equal modulus decomposition (EMD) and singular value decomposition (SVD). First, the primary image is converted into a QR code and then multiplied with a spiral phase mask (SPM). Next, the product is spiral phase transformed with particular spiral phase function, and further, the EMD is performed on the output of SPT, which results into two complex images, Z₁ and Z₂. Among these, Z,₁ is further Fresnel propagated with distance d, and Z₂ is reserved as a decryption key. Afterwards, SVD is performed on Fresnel propagated output to get three decomposed matrices i.e. one diagonal matrix and two unitary matrices. The two unitary matrices are modulated with two different SPMs and then, the inverse SVD is performed using the diagonal matrix and modulated unitary matrices to get the final encrypted image. Numerical simulation results confirm the validity and effectiveness of the proposed technique. The proposed technique is robust against noise attack, specific attack, and brutal force attack. Simulation results are presented in support of the proposed idea.

10 illus, 59 ref

024200   FELIX-RENDON U, LOPEZ-AGUAYO S (Tecnologico de Monterrey, N.L. Mexico- 64849, Email: servando@itesm.mx) : Solitons in PT -symmetric optical Mathieu lattices. J Optics 2018, 20(1), 15606.

We report the existence of stable optical spatial solitons in PT -symmetric optical Mathieu lattices. We find that Mathieu lattices allow a double phase transition between either having pure real or complex spectra by varying the particular continuous q parameter of the corresponding Mathieu lattice. We find that the q parameter can also modify the physical properties of the solitons, such as their shape, stability and dynamics. Moreover, this q parameter can be used to engineer the Mathieu lattice as an optical isolator for potential applications in light control.

9 illus, 38 ref

024199   WANG Z, PEI C, XIA M, YIN Y, XIA Y,YIN J (Normal Univ, Shanghai- 200 241, People's Republic of China, Email: ylyin@phy.ecnu.edu.cn) : Generation of elliptical and circular vector hollow beams with different polarizations by a Mach?Zehnder-type optical path. J Optics 2018, 20(1), 15605.

We present an experimental approach to convert linearly polarized Gaussian beams into elliptical and circular vector hollow beams (VHBs) with different polarization states. The scheme employed is based on a Mach–Zehnder-type optical path combined with a reflective spatial light modulator (SLM) in each path. The resulting VHBs have radial, azimuthal, and other polarization states. Our studies also show that the size of the generated VHBs remains constant during the propagation in free space over a certain distance, and can be controlled by the axial ratio of the SLM’s binary phase plate. These studies deliver great optical parameters and hold promising applications in the fields of optical trapping and manipulation of particles.

6 illus, 28 ref

024198   KUMAR V, ANWAR A, SINGH R P (Physical Research Laboratory, Gujarat-380 009, Email: vijaykumarsop@gmail.com) : Structuring stokes correlation functions using vector-vortex beam. J Optics 2018, 20(1), 15604.

Higher order statistical correlations of the optical vector speckle field, formed due to scattering of a vector-vortex beam, are explored. Here, we report on the experimental construction of the Stokes parameters covariance matrix, consisting of all possible spatial Stokes parameters correlation functions. We also propose and experimentally realize a new Stokes correlation functions called Stokes field auto correlation functions. It is observed that the Stokes correlation functions of the vector-vortex beam will be reflected in the respective Stokes correlation functions of the corresponding vector speckle field. The major advantage of proposing Stokes correlation functions is that the Stokes correlation function can be easily tuned by manipulating the polarization of vector-vortex beam used to generate vector speckle field and to get the phase information directly from the intensity measurements. Moreover, this approach leads to a complete experimental Stokes characterization of a broad range of random fields.

7 illus, 48 ref

024197   BARBERO S, PORTILLA J (Consejo Superior de Investigaciones Cientificas (IO, CSIC),, E-28006, Spain, Email: sergio.barbero@csic.es) : Efficient characterization of phase space mapping in axially symmetric optical systems. J Optics 2018, 20(1), 15603.

Phase space mapping, typically between an object and image plane, characterizes an optical system within a geometrical optics framework. We propose a novel conceptual frame to characterize the phase mapping in axially symmetric optical systems for arbitrary object locations, not restricted to a specific object plane. The idea is based on decomposing the phase mapping into a set of bivariate equations corresponding to different values of the radial coordinate on a specific object surface (most likely the entrance pupil). These equations are then approximated through bivariate Chebyshev interpolation at Chebyshev nodes, which guarantees uniform convergence. Additionally, we propose the use of a new concept (effective object phase space), defined as the set of points of the phase space at the first optical element (typically the entrance pupil) that are effectively mapped onto the image surface. The effective object phase space provides, by means of an inclusion test, a way to avoid tracing rays that do not reach the image surface.

6 illus, 22 ref

024196   EL-NICKLAWY M M, ABD-RABOU A M, ELMAHDY A E (Physics Dep, Helwan Univ, Cairo, Egypt, Email: afaf_mahmoud@science.helwan.edu.e.g.) : New analytical expression for speckle contrast of spectral light broadening. J Optics 2018, 20(1), 15602.

A new analytical expression for the average speckle contrast is derived for surfaces of random roughness at reflection. Rayleigh and Simpson phase probability density distributions of nonzero phase mean value are assumed for the roughness of the surface. The behavior of a speckle contrast with a roughness root mean square of phase deviation is presented. The effect of the spectral light profile, its spectral width, the density of the scatterers of the rough surface and the average time delay between the interfering beams are taken into consideration.

13 illus, 19 ref

024195   JALVISTE E, PALM V, PEET V (Tartu Univ, Tartu- 50411, Estonia, Email: vikp@ut.ee) : Vortex light beams in a degenerate two crystal cascade conical refraction. J Optics 2018, 20(1), 15601.

The transformation of circularly polarized Laguerre–Gauss optical vortex beams with topological charge ℓ = 1 focused through a cascade of two identical biaxial crystals along their optical axes is considered. For such an arrangement, the effect of degenerate conical refraction (CR) produces in the focal image plane a light pattern consisting of a central component and a ring. The relative integral intensity of these two components depends on the rotation angle between the crystals about the beam axis. It is shown that the central component, which appears due to the reversed CR in a degenerate two-crystal arrangement, is a composite vortex consisting of two superimposed vortices identical to the input beam. A single vortex can be selected from this superposition by a polarization control of light components entering the second crystal in the cascade. Such a polarization control also allows the formation of a central vortex possessing ℓ = 3, or can inverse the input vortex charge ℓ = 1 to ℓ = -1. The ring, which appears due to the additive action of two crystals, consists of two interfering components with different vorticity and opposite circular polarizations. For these two components, the vortex charge differs by one and varies from ℓ = -1 to ℓ = 3 depending on the polarization and vorticity of the light entering the second crystal. A numerical study of cascaded CR with vortex beams has been carried out; the numerical simulation results obtained are in a good agreement with experimental observations.

7 illus, 1 table, 29 ref