001096   Heda N L;Mathur S;Ahuja B L (Physics Dep, College of Science Univ, Udaipur-313 001) : Compton profiles of CdS, CdSe and CdTe: theory and experiment. Asian J Chem 2006, 18(5), 3279-82.

Reports the Compton profiles of zinc-blende CdS, CdSe and CdTe which are measured using 59.54 keV γlemda-rays from ²⁴¹ Am source. The isotropic experimental Compton profiles are compared with the present hybridised density functional and Hartree-Fock (DF-HF); and pseudopotential calculations using CRYSTAL03 code. To compare the relative bonding in these compounds the equal-valence-electron-density (EVED) profile are also derived. It is seen that the experimental profiles are in better agreement with DF-HF calculations while the ionicity decreases in the order CdSe, CdS and CdTe.

2 illus, 11 ref

001095   Hafiz M A (NO, Institute of Nuclear Science & Technology, Atomic Energy Research Esta, GPO Box 3787, Dhaka, Bangladesh, Email: hafizmab@yahoo.com) : Measurement of excitation functions of the reactions <. Indian J pure appl Phys 2007, 45(5), 425-8.

Excitation functions of the reactions ⁵⁸Ni(n,2n)⁵⁷Ni and ⁶⁵Cu(n,2n) ⁶⁴Cu in the neutron energy range 13.90-14.70 MeV have been measured using activation technique. Neutrons were produced via D-T reaction using solid tritium target at J-25 neutron generator of the Institute of Nuclear Science and Technology (INST), Savar, Dhaka, Bangladesh, with deuteron energy of 110 keV and beam current of <126>120 mA. Activities of the reaction products have been measured using HPGe detector gamma-ray spectrometry system. Neutron flux at each sample position was determined by using the monitor reaction ²⁷Al(n,a) ²⁴Na. Uncertainties in the measured cross-section values include statistical and systematic errors. Theoretical cross-sections were calculated using computer code SINCROS-II. Measured cross-section values fit fairly well with the literature data and lie within 24.71±4.07 to 38.84±4.82 mb for the ⁵⁸Ni(n,2n) ⁵⁷Ni and 826.0±62.4 to 960.7±63.2 mb for the ⁶⁵Cu(n,2n) ⁶⁴Cu reactions, respectively. SINCROS-II values are about 1.1 times the measured values for both the cases.

001094   Goraya P S;Sanwal B B;Ravinder Singh (Physics Dep, Punjabi Univ, Patiala-147 002, Email: paramjitgoraya@yahoo.com) : Variation of radiation in comet Hale-Bopp. Asian J Chem 2006, 18(5), 3381-3.

Reports the short-term and long-term variations in the total visual radiation from the coma of comet Hale-Bopp The overall emission of radiation from the comet is discussed. The raw data on total magnitudes were gathered from the international Astronomical Union Circulars. These data were converted to heliocentric magnitude (H) to remove the effect of the magnitude variations due to varying geocentric distance. Also compared the observed light curve with the predicted one.

1 illus, 6 ref

001093   Goraya P S (Physics Dep, Punjabi Univ, Patiala-147 002, Email: paramjitgoraya@yahoo.com) : Variation of radiation in pleione during shell and be phases. Asian J Chem 2006, 18(5), 3310-13.

The analysis of the spectrophotometric observations of Pleione, a wonderful object in Pleiades cluster, has been carried out in the wavelength range of 3200-5500 A. The amount of emitted radiation at Balmer continuum and Balmer jump has been measured in term of magnitudes. Present measurements have been combined with the earlier measurements to investigate the relation between the variation of the emitted radiation and phase changes in Pleione.

1 illus, 19 ref

001092   Goraya P S (Physics Dep, Punjabi Univ, Patiala-147 002, Email: paramjitgoraya@yahoo.com) : Emission of continuum radiation from bright be stars. Asian J Chem 2006, 18(5), 3306-9.

Continuum radiation distribution observations of Be stars are presented in the wavelength region 3200-8000 A. The effective temperature of Be stars are derived by comparing the observed energy distribution curves with the theoretical models. Various peculiarities detected in Be stars are discussed. Three Be stars are found to possess near-UV and near-IR excess radiation emission.

1 illus, 1 table, 11 ref

001091   Ghosh D;Deb A;Haldar P K;Guptaroy S (Nuclear and Particle Physics Research Centre, Physics Dep, Jadavpur University, Kolkata-700 032, Email: dipakghosh_in@yahoo.com) : Study of multidimensional fluctuations and non-thermal phase transition in ring like and jet like events in ultrarelativistic nuclear collisions. Indian J pure appl Phys 2007, 45(5), 419-24.

Non-thermal phase transition for ring like and jet like events for pions produced in ³²S-AgBr interactions at 200 A GeV has been studied. The study has been performed in the frame work of two-dimensional factorial moment methodology using the concept of Hurst exponent (H) to take care of anisotropic phase-space. An indication of non-thermal phase transition in jet like events only is revealed by the data.

001090   El Nahass M M;El-Barry A M A (Physics Dep, Faculty of Education, Ain Shams University, Cairo, Egypt, Email: elsevier56@yahoo.com) : Effect of substrate temperatures, deposition rate and heat treatment on structural and carrier transport mechanisms of thermal evaporated p-Cu₂S/n-CdS heterojunction. Indian J pure appl Phys 2007, 45(5), 465-75.

The p-Cu₂S/n-CdS heterojunction (Hj) has been fabricated by vacuum deposition of p-Cu₂S thin film onto n-CdS thin film. CdS layer was evaporated at substrate temperature, T_s ^<126> 473 K and rate of deposition <126>0.06 μm/min. The dark-temperature-current density-voltage (J-V-T) and illumination characteristics were measured over a reasonable temperature range (303-423K). The conduction mechanism was suggested to be thermo ionic for forward applied voltage <62> 0.2V. For higher voltage, the space charge limited current was the predominant mechanism. In the reverse direction, the generation and recombination mechanisms were the operating mechanisms. Finally, the photovoltaic characteristics and the spectral response of p-Cu₂S/n-CdS were also studied.

001089   Bhatti H S;Dhiraj Kumar;Karamjit Singh;Sharma P;Gupta A;Sharma R (Physics Dep, Punjabi Univ, Patiala-147 002) : Nanostructures of lead doped zinc oxide: synthesis and characterization. Asian J Chem 2006, 18(5), 3301-5.

Lead doped ZnO nanocrystallites have been synthesized in the laboratory using low temperature chemical precipitation technique. Precursor was prepared using absolute ethanol, zinc acetate and lead acetate in fixed proportions. Precipitates were obtained by adding 0.14 M LiOH into the precursor solution. Scanning electron microscopy images were obtained for studying morphology of the synthesized doped nanophosphors. Photoluminescence in the visible region has been recorded. Owing to increased quantum efficiency, these nanophosphors can be utilized for various industrial applications such as coating materials for fluorescence tubes, optical memories, bio-sensors, active medium for laser oscillations.

1 illus, 1 table, 22 ref

001088   Battisha I K;Beyally A El;Soliman S L;Nahrawi A M S (Solid State Physics Dep, National Research Center, Guiza, Egypt, Email: szbasha@yahoo.com) : Structural and optical studies of activated thin film and monolith nano-structure silica gel with different rare earth elements prepared by sol - gel techniques. Indian J pure appl Phys 2007, 45(5), 441-3.

Rare earth (Pr⁺³, Eu⁺³, Er⁺³ and Ho⁺³ ions) doped silica gel with different concentrations in the range 1-6% of each element, in the form of thin film and monolith materials have been studied by X-ray diffraction (XRD). The types of structural information obtainable have been compared in detail. The XRD spectra of a-crystobalite are obtained for the two type of materials and even by doping with the four rare earth element (REEs) at higher sintering heat treatment temperature. The structure study revealed that the crystallite size of pure monolith nano-structure silica gel was about 20.9 nm sintered at 1200°C, which decreased to 12.1 nm by doping with 6% of holmium ions at the same temperature. Optical measurements of both type of materials were also studied and compared. The normal transmission and specular reflection were measured. The coarse and fine microstructures of the monolith and thin film prepared samples were depicted by transmission electron microscope (TEM), which revealed the presence of nano-structure scale in the prepared samples, confirming the data obtained from XRD.

001087   Awasthi O N;Pundhir V K (Physics Dep, Regional Institute of Education, National Council of Educational Research & Training, Bhopal-462 013, Email: omnarain_awasthi@yahoo.co.in) : Ultrasonic attenuation in liquid mercury, zinc and gallium metals. Indian J pure appl Phys 2007, 45(5), 435-6.

Ultrasonic attenuation in mercury, zinc and gallium metals has been studied using the concept of a two-state thermodynamical model for the liquids near the melting points. The theoretical results, so obtained, have been compared with the experimental values and necessary explanations have been offered for any deviations in the results.

001086   Awana V P S;Ansari M A;Gupta A;Saxena R B; Kishan H (NO, National Physical Laboratory, K.S. Krishnan Marg, New Delhi-110 012) : Co-existence of magnetism and superconductivity in RuSr₂GdCu₂O_10-δ (Ru-1212) and RuSr₂Gd_1.5Ce_0.5Cu₂O_{10-<10 0>} (Ru-1222) Rutheno-cuprat compounds. Indian J Cryogenics 2005, 30(2), 63-9.

According to a long-term common sense, superconductivity and long-range magnetic order do not mutually co-exist within a single (thermodynamical) phase. Nevertheless, coexistence of high temperature superconductivity and magnetism was reported for a rutheno-cuprate, RuSr₂(Gd₀.7Ce_0.3)₂Cu₂O_{10-<100>< F255>} (Au-1222) and, more recently, for RuSr₂GdCu₂O_10-δ (Ru-1212). These reports have renewed the interest in the possible coexistence of superconductivity and magnetism. It is important to note that the possible coexistence of superconductivity and magnetism (in particular ferromagnetism) has been a topic of debate for decades even in the case of more homogeneous intermetallic compounds. ln particular, the microscopic length scales, in terms of the superconducting coherence length, and the long-range magnetic ordering, are important. Also in high temperature superconducting compounds, large anisotropy within the unit cell and microscopic compositional variations due to different cation intermixing or the variation in oxygen content are often seen. In such a situation, the possibility of magnetic but not superconducting solid solutions coexisting microscopically with superconducting but not magnetic material cannot be ruled out without ambiguity reviewed the existing literature critically and present data in terms of phase formation, structural, thermal, magnetic, electrical, spectroscopic and microscopic characterization for both Au-1212 and Au-1222. It is concluded that the coexistence of superconductivity and magnetism, in particular, the ferromagnetism at microscopic level in both these phases, need to be debated.

6 illus, 27 ref

001085   Ashok Kumar;Sukhpal Singh;Thind K S;Mudahar G S (Physics Dep, Punjabi Univ, Patiala-147 002) : Buildup factor under different geometrical conditions for 1332 ke V gamma rays. Asian J Chem 2006, 18(5), 3348-51.

The simultaneous effect of longitudinal thickness and beam divergence has been studied on the buildup factor of six wood samples of popular, dek, toot, safeda, black talhi and beri for 1332 keV gamma rays. It has been observed that the buildup factor is maximum for beri and minimum for dek for a fixed longitudinal thickness and collimator size. The buildup factor is nearly unity for small collimator size and absorber thickness, but it increases with increase in longitudinal thickness and collimator size.

2 illus, 5 ref

001084   Ashavani Kumar;Khanesh Kumar;Singh N P (Phys Dep, Sant Longowal Institute of Engineering and Technology, Longowal-148 106) : Response of the CR39 nuclear track detector to relativistic Si<. Asian J Chem 2006, 18(5), 3418-21.

The response of the CR-39 nuclear track detector for 5 A GeV Si¹⁴⁺ ions and their fragments has been presented heavy ions. Well separated peaks are observed from Z=7 to 14, indicating the detector threshold Z = 7 in the present condition. The charge resolution of the detector is σ <126> le at Z = 10.

1 illus, 19 ref

000095   Shanmugavel R;Rajamanickam N (NO, Physics Research Centre, V.H.N.S.N. College, Virudhunagar-626 001, Email: nrmanickam@rediffmail.com) : Electronic transition probability data : astrophysically useful parameters for lithium and silicon molecules. Asian J Spectrosc 2006, 10(1-2), 59-63.

Electronic transitions of band systems of the lithium and silicon molecules are useful, specially in UV region as astrophysically considerable diatomic molecules to be looked for in ISM, galactic halos. star-forming regions and other such astrophysical sources. The Franck-Condon factors and r -centroids which-are very closely related to electronic transition probabilities, have been computed by "a more reliable numerical integration procedure for the bands of C¹<71>I_u - X ^lΣ⁺_g system of Li₂ and K³Σ⁺_u X^lΣ⁺_g N ³Σ⁺_u - X ^lΣ⁺_g and O³Σ⁺_g X ^lΣ⁺_g systems of Si₂ using a suitable potential.

4 tables, ref

000094   Rajamanickam N;Nithya S;Karthikeyan B (NO, Physics Research Centre, V.H.N.S.N. College, Virudhunagar-626 001) : Transition probability parameters for certain band systems of Au₂ and AuD molecules. Asian J Spectrosc 2006, 10(1-2), 55-8.

Franck- Condon factors (transition probabilities) and r- centroids have been evaluated by the reliable numerical integration procedure for the band systems of A I_u ←X ⁱΣ_g⁺, B' l_u ←X ⁱΣ_g⁺ of Au₂, and B0⁺ ←X ⁱΣ⁺ of AuD.

3 tables, 9 ref

000093   Rajamanickam N;Devi N Sumangala;Karthikeyan B (NO, Physics Research Centre, V.H.N.S.N. College, Virudhunagar-626 001) : Franck-condon factors and r-centroids for the band systems a - X, b - X and c - X of AuH molecule. Asian J Spectrosc 2006, 10(1-2), 51-4.

Franck-Condon factors and r-centroids, which are very closely related to transition probabilities, have been evaluated by a more reliable numerical integration procedure for the bands of a2 ←X ⁱΣ⁺, bl ←X ⁱΣ⁺ and BO^- ←X ⁱΣ⁺ systems of.AuH molecule.

4 tables, 7 ref

000092   Kuriakose S;Vijayan K K;Syamalakumari B;Nair K P R;Rasheed T M A (Physics Dep, Cochin univ of Science and Technology, Cochin-682 022) : NIR spectrum of phenyl hydrazine- a local mode analysis. Asian J Spectrosc 2006, 10(1-2), 65-70.

Vibrational overtone absorption spectrum of liquid phase phenyl hydrazine in the near infrared region is reported. The analysis of the observed CH and NH local mode mechanical frequency values show that the lone pair interaction involved between one of the NH and the adjacent nitrogen lone pair causes two bands of different frequency. The study also reveals a net electron withdrawing effect of -NH-NH₂ from the phenyl ring in the absence of lone pair conjugation with the ring π electron system. The anharmonicty values of NH¹ and NH² show that the potential energy curve become more harmonic in phenyl hydrazine than that in hydrazine.

3 illus, 1 table, 9 ref

000095   Shanmugavel R;Rajamanickam N (NO, Physics Research Centre, V.H.N.S.N. College, Virudhunagar-626 001, Email: nrmanickam@rediffmail.com) : Electronic transition probability data : astrophysically useful parameters for lithium and silicon molecules. Asian J Spectrosc 2006, 10(1-2), 59-63.

Electronic transitions of band systems of the lithium and silicon molecules are useful, specially in UV region as astrophysically considerable diatomic molecules to be looked for in ISM, galactic halos. star-forming regions and other such astrophysical sources. The Franck-Condon factors and r -centroids which-are very closely related to electronic transition probabilities, have been computed by "a more reliable numerical integration procedure for the bands of C¹<71>I_u - X ^lΣ⁺_g system of Li₂ and K³Σ⁺_u X^lΣ⁺_g N ³Σ⁺_u - X ^lΣ⁺_g and O³Σ⁺_g X ^lΣ⁺_g systems of Si₂ using a suitable potential.

4 tables, ref

000094   Rajamanickam N;Nithya S;Karthikeyan B (NO, Physics Research Centre, V.H.N.S.N. College, Virudhunagar-626 001) : Transition probability parameters for certain band systems of Au₂ and AuD molecules. Asian J Spectrosc 2006, 10(1-2), 55-8.

Franck- Condon factors (transition probabilities) and r- centroids have been evaluated by the reliable numerical integration procedure for the band systems of A I_u ←X ⁱΣ_g⁺, B' l_u ←X ⁱΣ_g⁺ of Au₂, and B0⁺ ←X ⁱΣ⁺ of AuD.

3 tables, 9 ref

000093   Rajamanickam N;Devi N Sumangala;Karthikeyan B (NO, Physics Research Centre, V.H.N.S.N. College, Virudhunagar-626 001) : Franck-condon factors and r-centroids for the band systems a - X, b - X and c - X of AuH molecule. Asian J Spectrosc 2006, 10(1-2), 51-4.

Franck-Condon factors and r-centroids, which are very closely related to transition probabilities, have been evaluated by a more reliable numerical integration procedure for the bands of a2 ←X ⁱΣ⁺, bl ←X ⁱΣ⁺ and BO^- ←X ⁱΣ⁺ systems of.AuH molecule.

4 tables, 7 ref

000092   Kuriakose S;Vijayan K K;Syamalakumari B;Nair K P R;Rasheed T M A (Physics Dep, Cochin univ of Science and Technology, Cochin-682 022) : NIR spectrum of phenyl hydrazine- a local mode analysis. Asian J Spectrosc 2006, 10(1-2), 65-70.

Vibrational overtone absorption spectrum of liquid phase phenyl hydrazine in the near infrared region is reported. The analysis of the observed CH and NH local mode mechanical frequency values show that the lone pair interaction involved between one of the NH and the adjacent nitrogen lone pair causes two bands of different frequency. The study also reveals a net electron withdrawing effect of -NH-NH₂ from the phenyl ring in the absence of lone pair conjugation with the ring π electron system. The anharmonicty values of NH¹ and NH² show that the potential energy curve become more harmonic in phenyl hydrazine than that in hydrazine.

3 illus, 1 table, 9 ref

001177   Vijay Kumar;Sonkawade R G;Dhaliwal A S (Physics Dep, Sant Longowal Institute of Engineering and Technology, Longowal Distt. Punjab-148 106) : Optimization of CR-39 as neutron dosimeter. Indian J pure appl Phys 2010, 48(7), 466-9.

The chemical etching parameters (etching time, temperature, normality of etchant etc.) for use of CR-39 as neutron dosimeter have been optimized. The CR-39 films placed in polyethylene radiator were exposed to ^{252Cf neutron source for different time intervals and the neutron fluences were varied from 4.68 x 106 to 2.7 x 108n/cm2. Etched tracks were analyzed and counted at 400X with microscope and neutron recoil track density was calculated after every hour of etching. It was found that the track density increases up to a certain etching time and then decreases for higher etching time, which is considered due to removal of shallow tracks and overlapping of the tracks due to their size enlargement. Optimized etching conditions found are, 7 N NaOH solution at 70°C (±) for 9 hr with continuous stirring. However, we found a linear relationship between neutron fluence and track density. UV-visible spectra were also obtained and analyzed for the pristine and neutron irradiated CR-39 films in the wavelength range 200-700 run at room temperature. As seen from absorption spectra, the absorption edge is shifted towards longer wavelength with increase of fluence and therefore, indicates a decrease in the band gap. The study may be important for the future high energy accelerators and Radioactive Ion Beam Facilities where CR-39 can be used as a neutron dosimeter.}

4 illus, 20 ref

001176   Varshney R;Mahur A K;Sonkawade R G;Suhail M A;Azam A;Prasad R (Applied Physics Dep, Z H College of Engineering & Technology, Aligarh Muslim Univ, Aligarh-202 002) : Evaluation and analysis of <. Indian J pure appl Phys 2010, 48(7), 473-7.

The natural terrestrial gamma radiation dose rate is an important contribution to the average dose rate received by the world's population. Natural radio nuclides in building material are sources of external and internal radiation exposure in dwellings. The natural radioactivity and radon exhalation rate of the commonly used building construction material (grey cements) have been studied. Positive correlation was found between radium concentration and radon concentration. The external radiation exposure caused by gamma emitting radionuclide is determined from obtained values of ^{226Ra, 232Th and 40K, using high purity Germanium Detector. The absorbed dose is found to be higher in the AMB cement. This study presents the results of estimation of 226Ra, 232Th and 40K concentration, gamma absorbed dose rates and radon exhalation rates of grey cements collected from different manufacturers.}

1 illus, 3 tables, 19 ref

001175   Tjon J A;Wallace S J (Physics Dep, Utrecht Univ, 3508 TA Utrecht, Netherland, Email: j.a.tjon@phys.uu.nl) : Eikonal analysis of coulomb distortion in quasi-elastic electron scattering. Indian J Phys 2009, 83(5), 693-711.

An eikonal expansion is used to provide systematic corrections to the eikonal approximation through order 1/k^{2, where k is the wave number. Electron wave functions are obtained for the Dirac equation with a Coulomb potential. They are used to investigate distorted-wave matrix elements for quasi-elastic electron scattering from a nucleus. A form of effective-momentum approximation is obtained using trajectory-dependent eikonal phases and focusing factors. Fixing the Coulomb distortion effects at the center of the nucleus, the often-used ema approximation is recovered. Comparisons of these approximations are made with full calculations using the electron eikonal wave functions. The ema results are found to agree well with the full calculations.}

6 illus, 3 tables, 38 ref

001174   Tamilarasan K;Perumal K;Srinivasan P S S (Physics Dep, Kongu Engineering College, Erode-638 052, Email: tamilvasanthi@yahoo.com) : Performance of natural and wind assisted domestic solar hot water systems: a comparative experimental study. J Energy Heat Mass Transfer 2009, 31(2), 145-55.

Natural circulation type domestic hot water systems are widely used nowadays due to cost effectiveness; however the efficiencies are lower due to lower collector flow rates, because of natural circulation. A vertical axis windmill driven propeller type pump is added to the existing Natural Circulation System (NCS) to increase the flow rate. Whenever there is a wind flow, the wind driven pump will provide circulation. Such a system is fabricated and tested against NCS mode experimentally on four sunny days. It is observed that the collector flow rates in Windmill Assisted System (WAS) are a function of wind velocity. Even if the wind velocity is zero, the flow rate will reach the lower bound value of NCS mode. Thus, any wind flow will increase the flow rate and thus the efficiency. The efficiencies of WAS system are over 10% higher than NCS mode. Windmill driven pump Assisted System (WAS) appears to be a better method to enhance the efficiency of the existing Natural Circulation Domestic Solar Water Heating Systems.

9 illus, 2 tables, 12 ref

001173   Talvinder Singh;Ashok Kumar;Naithani U C (Physics Dep, H N B Garhwal Central Univ, Campus Pauri, Garhwal-246 001, Email: talv_inder@yahoo.co.in) : Field dependent sound attenuation in PbTiO₃ and KNbO₃ ferroelectric perovskites. Indian J pure appl Phys 2010, 48(5), 343-8.

The electric field dependence of the sound attenuation in anharmonic pure PbTiO₃ and KNbO₃ ferroelectric perovskites has been theoretically calculated in paraelectric phase from the Silverman-Joseph Hamiltonian augmented with fourth-order phonon coordinates using double-time Green's function technique. The attenuation constant increases with increasing temperature and frequency in the presence of an electric field. In the vicinity of phase transition temperature, the anomalously increasing sound attenuation is the consequence of soft mode. The attenuation of sound wave is primarily due to strong interaction with thermally excited phonons in the soft mode. The results obtained are compared with the results of others.

4 illus, 30 ref

001172   Tak S K;Mangal R;Gupta A K (Physics Dep, Marudhar Engg. College, Bikaner, Email: sktak07@rediffmail.com) : Mechanical properties of textured electrical porcelain. Int J pure appl Phys 2009, 5(3), 263-9.

Textured samples prepared from 45% kaolin, 25% feldspar and 30% quartz were fired at selected temperatures from 200 to 1320°C. Young's modulus and flexural strength were measured. The results showed the dependence of mechanical properties on the orientation of the kaolinite crystals in the sample. Young's modulus is higher along the basal planes of the kaolinite crystals. Flexural strength had lower values if a force affected the sample collinearly with basal planes of the kaolinite crystals. Both mechanical strength and Young's modulus showed that the texture effects persisted even after firing.

7 illus, 2 tables, 9 ref

001171   Sonkawade R G;Vijay Kumar;Lalit Kumar; Annapoorni S;Vaijapurkar S G;Dhaliwal A S (NO, Inter Accelerator Centre Univ, Aruna Asif Ali Marg, New Delhi-110 067, Email: rgs22@rediffmail.com) : Effects of gamma ray ad neutron radiation on polyanilne conducting polymer. Indian J pure appl Phys 2010, 48(7), 453-6.

Ionizing radiation effects such as neutron and gamma on conducting polyanilne have been studied for various doses varied from 6 to 504Gy and 15 to 41.9 kGy, respectively. Spectroscopic methods such as UV-Vis spectroscopy, X-ray diffraction, Raman spectroscopy and I-V measurements have been used to characterize the pristine and irradiated polyanilne samples. UV-visible spectroscopy shows a shift in the absorption edge towards visible region after irradiation, which can be correlated to the transition involved in these polymers and variation in the band gaps (Eg) using Tauc's expression which indicate a decrease in band gap. XRD spectra revealed that crystallinity and particle size improve after irradiation, which could be attributed to cross-linking mechanism. The current voltage (I-V) characteristics have been carried out at room temperature using four probe set up and it has been found that polyaniline films show ohmic behaviour before and after irradiation. Moreover, conductivity improves after irradiation, which is due to enhancement in carrier concentration. Conducting polymers as a radiation sensor for gamma and neutron as well as for dosimetry aspects have been studied.

6 illus, 23 ref

001170   Singh R K;Singh A K (Mathematics Dep, Banaras Hindu Univ, Varanasi-221 005) : Hydromagnetic mixed convection between two vertical walls. J Energy Heat Mass Transfer 2009, 31(2), 111-23.

Mixed convective flow of an electrically conducting and viscous incompressible fluid between two vertical walls has been considered when the applied magnetic field is perpendicular to the walls and there is a uniform axial temperature variation along the walls. The magnetic Reynolds number is taken small so that the induced magnetic field can be neglected. The analytical solution has been obtained for the three different cases and as expected the velocity profiles have symmetric property in all the cases. It is found that flow is of parabolic type for lower values of Rayleigh number. The parabolic character of the flow formation changes to reversal type with increase in value of Rayleigh number and the velocity of fluid acquire maximum value near the walls for large value of Rayleigh number. The effect of magnetic field is to decrease the velocity ofthefluid.

8 illus, 21 ref

001169   Singh P;Rajesh Kumar;Virk H S;Rajendra Prasad (Physics Dep, School of Basic & Applied Science, Guru Gobind Singh Indraprastha Univ, Delhi-110 043) : Modification of optical, chemical and structural response of polymethyl methacrylate polymer by 70 MeV carbon ion irradiation. Indian J pure appl Phys 2010, 48(5), 321-5.

Polymethyl methacrylate (PMMA) foils were irradiated under vacuum with 70 MeV C^{5+ ions to the fluences of S.lxl011, 3.7x1012, l.SxlO13, 5.6xl013 and 1.2xl014 ions cm-2. Ion induced optical, chemical and structural modifications were studied by ultraviolet, visible (UV-Vis) and Fourier Transform Infrared (FTIR) spectroscopy and X-ray diffractometer (XRD). PMMA suffers degradation under irradiation, UV-Vis data show the increase of optical absorbance and the shift of absorption edge from the UV towards visible with the increase of the fluences, attributing to the formation of conjugated system of bonds. The intensity of infrared bands and characteristics of different chemical functional groups are found to decrease with Swift Heavy Ion (SHI). Crystallite size of irradiated sample shows a decrease of 8%.}

3 illus, 2 tables, 31 ref

001168   Singh D P;Upmanyu A (Physics Dep, Govt. College, Dera Bssai-140 507, Email: drdpsn@hotmail.com) : Thermo-acoustic studies of trans-4-cyano cinnamic acid ester liquid crystal. Int J pure appl Phys 2009, 5(3), 203-13.

Intermolecular interaction studies of trans-4-cyano cinnamic acid ester have been done over the temperature range 340 K to 393 K, using ultrasonic velocity and density data taken from literature^{1. Several acoustical parameters such as adiabatic compressibility, isothermal compressibility, acoustic impedance, van der Waal's constants, molecular radius, space filling factor, surface tension, pseudo-Gruneisen parameter, Debye temperature, enthalpy and Poisson's ratio have been determined. Various thermo-dynamical parameters such as available volume, refractive index, molar refraction, Eykmann constant, internal pressure, intermolecular free length and relative association have also studied. Free Length Theory and Collision Factor Theory have been applied to predict the ultrasonic velocity values in the system. The obtained results has been explained in terms of the temperature dependence of theses parameter and the intermolecular interaction present in the system, The present investigation provide a rich source of information about the type and extent of molecular interaction occurring in the liquid crystal.}

14 illus, 3 tables, 25 ref

001167   Singh B P;Pandit B;Bhardwaj V N;Singh P; Rajesh Kumar (Chemistry Dep, B S K College, S K M Univ, Barharwa, Sahibganj, Dumka, Jharkhand) : Radium and radon exhalation rate in some solid samples using solid state nuclear track detectors. Indian J pure appl Phys 2010, 48(7), 493-5.

Uranium is a radiotoxic element found in trace quantities in almost all natural occurring materials like soil, rock and sand etc. Radon an inert radioactive gas whose predecessor is uranium, is emitted from soil beneath the house and from building materials. The radium concentration and radon exhalation rates from some solid samples of some area of Santhal Pargana, Jharkhand using LR-115 Type-II plastic track detectors keeping in view the health hazard effects, have been measured. Small strips of LR-115 Type-II film were fitted in bare mode in an emanation chamber for 90 days. The values of radium concentration and radon exhalation rate are found to be maximum in Jamtara district and minimum in Godda district. The values are, generally, found to be more in soil compared with rock and sand samples.

2 tables, 15 ref

001166   Singh B P;Baghel V;Baghel K S (Physics Dep, Institute of Basic Sciences, Khandari, Agra-282 002, Email: drbps_ibs@yahoo.co.in) : Analysis of cohesive energy and bulk modulus of diatomic solids. Indian J pure appl Phys 2010, 48(5), 311-14.

Empirical relationships studied by Verma and Bhardwaj [J Phys: Condens Matter, 18 (2006) 8603] have been found to be simplified forms of the Born-modei with the power law and exponential potential functions. Values of cohesive energy and bulk modulus in case of NaCI under the effect of pressure have also been obtained. It has been found that the exponential potential function gives better agreement with the available experimental data as compared to the inverse power form.

1 illus, 2 tables, 22 ref

001165   Sharma G C;Jain M (School of Mathematical Sciences, Institute of Basic Science, Khandari, Agra-282 002, Email: gokulchandra@bsnl.in) : Mass and heat transfer for a hydromagnetic flow along a heated stretching plate with viscous dissipation through porous medium. J Energy Heat Mass Transfer 2009, 31(1), 39-47.

In this investigation an analysis is presented to study the effects of viscous dissipation on the steady laminar boundary layer MHD flow, mass and heat transfer past a heated stretching vertical plate through porous medium. Internal heat generation or absorption are taken into consideration in the heat transfer equation and mass transfer equation includes chemical reaction (source or sink). Obtained the exact solution of the flow equation and numerical solution of heat and mass transfer equation. The graphical demonstration is presented to visualize these results. The objective of the current work is to visualize the effect of magnetic parameter and viscous dissipation on the heat and mass transfer.

4 illus, 16 ref

001164   Sharma B R;Singh R N (Mathematics Dep, Bibrugarh Univ, Bibrugarh-786 004, Email: bishwaramsharma@yahoo.com) : Thermal diffusion in a binary fluid mixture confined between two concentric circular cylinders in presence of a radial magnetic field. J Energy Heat Mass Transfer 2009, 31(1), 27-38.

The effect of a uniform radial magnetic field on separation of a binary mixture of incompressible viscous thermally and electrically conducting fluids confined between two concentric stationary circular cylinders is examined. It is assumed that one of the components, which is rarer and lighter is present in the mixture in a very small quantity. The equations governing the motion, temperature and concentration in cylindrical polar coordinate are solved analytically. The solution obtained for concentration distribution is plotted against the radial distances from the surface of the inner circular cylinder for various values of non-dimensional parameters. It is found that the radial magnetic field favours the species separation of rarer and lighter component but the temperature gradient, the Prandtl number and the Eckert number retard the same. The problem discussed here derives its application in the basic fluid dynamics separation processes to separate the rarer component of the different isotopes of heavier molecules where electromagnetic method of separation does not work.

3 illus, 28 ref

001163   Semwal A;Negi A;Sonkawade R G;Rana J M S; Ramola R C (Physics Dep, H N B Garhwal Univ, Badshahi Thaul Campus, Tehri, Garhwal-249 199) : Effect of swift heavy ion irradiation on optical and structural properties of polysulphones polymer films. Indian J pure appl Phys 2010, 48(7), 496-9.

The structural and optical modifications of polysulphone polymer under swift heavy ion (SHI) irradiation have been compared. Polysulphone films were irradiated with 45 MeV Li^{+3 ions and 120 MeV Ni+9 ions with fluence varying from 3xl010 to 3x1012 ions/cm2. Optical and structural modifications were characterized by UV-visible spectroscpy and X-ray diffraction (XRD) method. It is observed that optical absorption increases with increasing fluence and the absorption edge shifts towards the red end of the spectrum. The value of band gap shows a decreasing trend with increasing ion fluences of both the ions but a sharp decrease in band gap was observed in case of Ni ion. XRD analysis shows the decrease in peak intensity with increasing fluence.}

5 illus, 2 tables, 10 ref

001162   Sanyasi Rao V V S;Gopika V;Ramteka P K;Hari Prasad M;Santhosh;Ghosh A K (Reactor Safety Div, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085) : Research and development activities in level-1 probabilistic safety assessment and againg studies. BARC Newsl 2010, (May-Jun), 37-54.

Research and development activities that are in progress in Reactor Safety Division in the areas namely Level-1 Probabilistic Safety Assessment (PSA) and ageing of control and instrumentation components and cables are presented. The results of AHWR level-1 PSA studies carried out are presented. PSA studies have applications in many areas. A software "Risk Monitor" was developed that can be used to continuously monitor the status of the Nuclear Power Plant (NPP) with regard to the functioning or non-functioning of its different subsystems and assess the associated risk emanating from the facility on the basis of this information. Probabilistic precursor analysis studies have been initiated for assessing risk arising out of the events that occurred during the operation of the plant. A case study has been carried out for a typical NPP. All the PSA studies are dependent on failure parameters that enter into various component models. A case study has been carried out, along with NPCIL and AERB for assessing more applicable failure parameters for class IV failure frequencies using Bayesian methods. Fire PSA studies have been carried out for MAPS, as a case study, to identify the vulnerable areas. Pilot studies on Risk informed In-Service-lnspection studies have been carried out, for a typical NPP and a section of Heavy Water Plant, for categorizing the components for In-Service inspection based on their contribution to risk. These two pilot studies indicate that RI-ISI has a very high potential in reducing inspection requirements compared to the requirements as per the currently adopted standards. A neural network based diagnostic system for identification of accident scenarios in 220 MWe Indian pressurized heavy water reactors (PHWRs) has been developed for operator support and accident management. Various facilities have been set up and a few were updated for carrying out the Thermal & Radiation Ageing and Loss Of Coolant Accident (LOCA) Qualification Studies of Control & Instrumentation (C&l) components and Equipments. Instrumentation systems for carrying out these studies are also being up dated. Now-a-days digital systems are increasingly being used in instrumentation and control. Studies based on physics of failure are in progress to address the issues related to their failure, which are needed in PSA. studies. Even though software that goes into these systems undergoes extensive validation and verification, quantification of the failure rates of these software are needed in PSA studies. Work on software reliability is also under way.

10 illus, 2 tabls, 10 ref

001161   Samhita L;Varshney U (Microbiology and Cell Biology Dep, Indian Institute of Science, Bangalore-560 012) : Ribosome and the 2009 nobel prize in chemistry. Resonance 2010, 15(6), 526-37.

The 2009 Nobel prize in chemistry was awarded jointly to Venkatraman Ramakrishnan, Thomas Steitz and Ada Yonath for studies on the structure and function of the ribosome". The ribosome is a massive molecular machine comprising proteins and RNA and is responsible for the synthesis of proteins, often termed the workhorses of the cell. Proteins are key players in almost all intracellular transactions and hence the importance of the ribosome.

3 illus, 5 ref

001160   Saikia U;Sharma N;Das A (High Altitude Zoological Field Station, Zoological Survey of India, Saproon, Solan, H.P.-173 211, Email: uttamsaikiazsi@rediffmail.com) : Vanishing species: the planet in crisis. Resonance 2010, 15(4), 321-36.

Rapid extinction of species is one of the most serious ecological problems faced by humanity today. Species are disappearing at a pace unprecedented in the history of the planet putting the very future of life at risk. The irony is that the root of the crisis is another species, Homo sapiens rather than some physical events that is poised to threaten its own survival. This article gives a brief introduction to the crisis, its consequences and possible mitigation strategies.

12 ref

001159   Rufus E;Alex Z C (NO, VIT Univ, Vellore-632 014, Email: elizabethrufus@vit.ac.in) : Dielectric properties of biological tissues in the microwave frequency range. Int J pure appl Phys 2009, 5(3), 253-61.

The complex dielectric constants at room temperature of various goat tissues (liver, muscle, kidney, heart and brain) and corn syrup were measured in the frequency range 1 to 10 GHz with the help of a HP Network Analyzer N5230A. Open ended coaxial cable method was employed for the measurement. The system imperfections are completely avoided by calibrating the system with four known materials and their reflection coefficients were used in the calculation along with the reflection coefficient of the sample. The relaxation frequency in the 5 region, spread of relaxation, volume fraction of protein present in tissues are calculated from the measured dielectric data. The dielectric constant of corn syrup samples suggests the feasibility of using corn syrup as a tissue equivalent for microwave imaging applications.

4 illus, 2 tables, 21 ref

001158   Rao M V P (NO, Indian Institute of Technology Hyderabad, Ordnance Factory Estate, Yeddumailaram-502 205, Email: mvp@iith.ac.in) : Computational lower bounds using diagonalization-II. Resonance 2010, 15(4), 337-46.

Discuss a powerful technique called diagonalization for arriving at lower bounds on computing resources for deciding languages. We will discuss the method, its success and possible limitations.

4 ref

001157   Ramesh Babu K;Shankar B (Mathematics Dep, Osmania Univ, Hyderabad-500 007) : Heat and mass transfer along a vertical plate in the presence of a magnetic field. J Energy Heat Mass Transfer 2009, 31(1), 21-6.

In this paper Heat and Mass Transfer along a Vertical plate in the Presence of a Magnetic field is investigated which has much Industrial applications. The temperature and concentration of the fluid at infinity is assumed as T ∞ and C∞ while at the plate as assumed as T_w and C_w, Numerical Technique is employed to study velocity, temperature and concentration distribution under various Magnetic parameter M and Prandtl number Pr. Interesting results are obtained for different Nusselt number and Sherwood number. The results are shown graphically.

4 illus, 4 ref

001156   Raju S P G (Aerospace Engineering Dep, Indian Institute of Science, Bangalore-560 012, Email: spg@aero.iisc.ernet ) : Aerobasics-an introduction to aeronautics. Resonance 2010, 15(4), 302-20.

Air navigation has evolved over the last hundred years from an art into a mature science. Airplane accidents due to navigational errors are practically nonexistent. In large measure this advance has been due to radio aids to navigation which operate under all weather conditions. However in remote areas and in hostile airspaces, the radio aids may not be available and a fully self contained navigational device is required. Navigation by stars (celestial navigation) is feasible under such conditions. But the inertial navigation system (INS) is the preferred choice. In recent times, a navigational instrument based on radio communication with specially designed satellites in low Earth orbits called the global positioning system (GPS) has become popular. This article deals with the principles of these various methods of air navigation.

10 illus, 6 ref

001155   Rajbongshi S C;Boruah P K;Boruah K (Electronics Sciences Dep, GU, Assam) : Development and testing of RPC module developed in the mini array laboratory, Gauhati university. Int J pure appl Phys 2009, 5(3), 195-202.

A Resistive Plate Chamber (RFC) module of size 15 cm x 15 cm has been developed and its performance tested in a cosmic ray setup. Performances have been tested using three different gas compositions using P-10 and Freon-134A at different bias voltages. A characteristic plateau region has been obtained for efficiency when measured with varying applied bias voltage. The maximum efficiency is obtained 92% and the performance is found to be stable.

8 illus, 7 ref

001154   Rajagopal K;Chenthilnath S (Physics Dep, Govt College of Engineering, Tirunelveli-627 007) : Excess thermodynamic studies of binary liquid mixtures of 2-methyl-2-propanol with ketones. Indian J pure appl Phys 2010, 48(5), 326-33.

Densities (p), ultrasonic speeds (u) and viscosities (η) of binary mixtures of 2-methyl-2-propanol (2M2P) with acetone (AC), ethyl methyl ketone (EMK) and acetophenone (AP) including those of pure liquids have been measured over the entire composition range at temperatures 298.15, 303.15 and 308.15 K, respectively. From these experimental data, the excess available volume, V^{E_a, excess free volume, VE_f, excess internal pressure, πE_i, excess intermolecular free length, LE_f, excess acoustic impedance, ZE and excess free energy of activation, ΔG*E are calculated. The variations of these properties with composition and temperature of the binary mixtures have been studied in terms of molecular interactions between unlike molecules of the mixtures. The theoretical viscosities have been evaluated using four standard models and the relative merits are studied in terms of the interaction parameters.}

6 illus, 3 tables, 20 ref

001153   Radhakrishnamurty P (NO, , 42, Shivakrupa 1st Floor, 3A Main, Manjunathanagar II Phase, Bangalore-560 010, Email: padyala1941@yahoo.com) : Maxwell's demon and the second law of thermodynamics. Resonance 2010, 15(6), 548-60.

A century and a half ago, Maxwell introduced a thought experiment to illustrate the difficulties which arise in trying to apply the second law of thermodynamics at the level of molecules. He imagined an entity (since personified as 'MawelPs demon') which could sort molecules into hot and cold and thereby create differences of temperature spontaneously, apparently violating the second law. This topic has fascinated physicists and has generated much discussion and many new ideas, which this article goes over. Particularly interesting is the insight given by deeper analysis of the experiment. This brings out the relation between entropy and information, and the role of irreversibility in computing as we understand it - topics still under discussion today.

1 illus, 5 ref

001152   Pinto G;Karunakara N;Somashekarappa H M;Rao C;Prabhu U;Yashodhara I (NO, University Science Instrumentation Centre, Mangalore Univ, Mangalagangotri-574 199) : Natural radioactivity in Udupi and Karkala taluks of coastal Karnataka. Indian J pure appl Phys 2010, 48(7), 527-9.

The gamma radiation levels, ^{226Ra, 232Th and 40K concentrations in soils of Udupi and Karkala Taluks of coastal Karnataka region of India have been studied in the present paper. The gamma absorbed dose rates were measured using portable GM survey meter. The soil radioactivity was measured by gamma spectrometry method using an HPGe detector. The results show that the 226Ra concentration varies in the range 2.6-78.0 Bq kg~' with a mean of 34.4 Bq kg-1, 232Th in the range 2.3-166.2 Bq kg-1 with a mean of 45.3 Bq kg-1 and 40K in the range 72.9-493.5 Bq kg-1 with a mean of 198.6 Bq kg-1 in the 0-5 cm soil profile. The gamma absorbed dose rates, measured using the GM survey meter, show that the dose varies in the range 70.0-123.0 nGy h-1. The regression analyses performed between the measured dose rates and that calculated from the primordial radionuclide activities show a poor correlation between the measured and calculated dose.}

1 table, 7 ref

001151   Pati J C (NO, SLAC Linear Acceleratory, Menlo Park, CA 940 25, Email: pati@physics.umd.edu) : Proton decay: the missing piece of grand unification. Indian J Phys 2009, 83(5), 645-7.

It is argued that one or more than one large megaton-size water cherenkov detector would be able to throw light on the three processes of fundamental significance in nature, namely proton decay, neutrino oscillations and neutrino-emission from the supernovae and pave the way to Grand Unification.

001150   Padmanabhan S;Sukhi Y (ECE Dep, AVIT, Chennai, Tamil Nadu, Email: gayathrisp@hexaware.com) : Analysis of regulated power supply using soft switched resonant convertiers. J Analysis Computn 2009, 5(1), 15-25.

The series parallel resonant converter is a preferred topology for dc-dc power conversion. A zero current switched pulse width modulated series parallel resonant converter is presented in this paper. The performance of the converter for constant output voltage with variable input is analysed. This configuration is well suited for many applications where output is fairly constant but the input is required to vary widely without serious switching losses and with significant reduction in ripple content. Experimental re suits obtained from a laboratory prototype are presented.

12 illus, 2 tables, 6 ref

001149   Nautiyal O P;Bhatt S C;Pant R P;Semwal B S (Physics Dep, H N B Garhwal Univ, Srinagar, Garhwal-246 174, Email: nautiyal_omprakash@yahoo.co.in) : Dielectric properties of silver sodium niobate mixed ceramic system. Indian J pure appl Phys 2010, 48(5), 357-62.

Ceramic pellets of silver sodium niobate (Ag_1-xNa_xNbO₃) mixed system of different concentration have been prepared by solid-state reaction method and sintering process. The prepared samples were characterized by X-ray diffraction method and SEM techniques. Frequency variations of dielectric constant, loss tangent and electrical conductivity have been investigated at room temperature in the frequency range 10 Hz-10 MHz.

10 illus, 10 ref