Interaction of oxygen (O+7) ion beam on polyaniline thin films

High-energy ion beam irradiation of the polymers is a good technique to modify the properties such as electrical conductivity, structural behaviour and mechanial properties. Polyaniline thin films doped with hydrochloric acid (HCl) were prepared by oxidation of ammonium persulphate. The effect of Swift Heavy Ions irradiation on the electrical and structural properties of polyaniline has been measured in this study. Polyaniline films were irradiated by oxygen ions (energy 80 MeV, charge state O+7) with fluence varying from 1 × 1010 to 3 × 1012 ions/cm2. The studies on electrical and structural properties of the irradiated polymers were investigated by measuring V-I using four probe set-up and X-ray diffraction (XRD) using Bruker AXS, X-ray powder diffractometer. V-I measurements shows an increase in the conductivity of the film, XRD pattern of the polymer shows that the crystallinity improved after the irradiation with Swift Heavy Ions (SHI), which could be attributed to cross linking mechanism.Subhash Chandra1*, S Annapoorni2, R G Sonkawade3, P K Kulriya3 Fouran Singh3, D K Avasthi3, J M S Rana1 and R C Ramola1 1Department of Physics, H N B Garhwal University, Badshahi Thaul Campus, Tehri Garhwal-249 199, Uttarakhand, India 2Department of Physics and Astrophysics, University of Delhi, Delhi-110 007, India 3Inter University Accelerator Center, Aruna Asaf Ali Marg, New Delhi-110 067, India E-mail : [email protected] of Physics, H N B Garhwal University, Badshahi Thaul Campus, Tehri Garhwal-249 199, Uttarakhand, India Department of Physics and Astrophysics, University of Delhi, Delhi-110 007, India Inter University Accelerator Center, Aruna Asaf Ali Marg, New Delhi-110 067, Indi

Numerical test of the Edwards conjecture shows that all packings are equally probable at jamming

In the late 1980s, Sam Edwards proposed a possible statistical-mechanical framework to describe the properties of disordered granular materials1. A key assumption underlying the theory was that all jammed packings are equally likely. In the intervening years it has never been possible to test this bold hypothesis directly. Here we present simulations that provide direct evidence that at the unjamming point, all packings of soft repulsive particles are equally likely, even though generically, jammed packings are not. Typically, jammed granular systems are observed precisely at the unjamming point since grains are not very compressible. Our results therefore support Edwards’ original conjecture. We also present evidence that at unjamming the configurational entropy of the system is maximal.S.M. acknowledges financial support by the Gates Cambridge Scholarship. K.J.S. acknowledges support by the Swiss National Science Foundation under Grant No. P2EZP2-152188 and No. P300P2-161078. D.F. acknowledges support by EPSRC Programme Grant EP/I001352/1 and EPSRC grant EP/I000844/1. K.R. and B.C. acknowledge the support of NSF-DMR 1409093 and the W. M. Keck Foundation

Analysis of seasonal variation of indoor radon concentration in Tehri Garhwal, Northern India

The seasonal variation analysis of indoor radon has been carried out in the hilly region of Tehri Garhwal, Northern India by using LR-115 Type II, plastic track detector. In the analysis the winter/summer ratio radon values were found to vary from 0.63 to 1.64 and 1.02 to 1.22 for cemented houses and mud houses, respectively. Over all the average value of winter/summer ratio was found maximum in both cemented and mud houses respectively.Author Affiliation: M S Kandari and R C Ramola 1.Department of Physics, Govt. P G Collage Kotdwara, Pauri Garhwal-246 149, Uttarakhand, India 2Department of Physics, H N B Garhwal University, Badshahi Thaul Campus, Tehri Garhwal-249 199, Uttarakhand, India E-mail : [email protected] of Physics, Govt. P G Collage Kotdwara, Pauri Garhwal-246 149, Uttarakhand, India 2Department of Physics, H N B Garhwal University, Badshahi Thaul Campus, Tehri Garhwal-249 199, Uttarakhand, Indi

Seasonal variation on radon emission from soil and water

Radon is being measured continuously in spring water and soil-gas at Badshahi Thaul Campus, Tehri Garhwal in Himalayan region by using radon Emanometer since December 2002. An effort was made to correlate the variance of radon concentrations in spring water and soil-gas with meteorological parameters at the same location. The main meteorological parameters that affect the radon emanation from host material is surrounding temperature, barometric pressure, wind velocity, rain fall and water level of the spring. The correlation coefficient between radon concentration in spring water and different atmospheric parameters was computed. The correlation coefficient between radon concentration in spring water and the maximum atmospheric temperature was 0.3, while it was 0.4 for minimum atmospheric temperature at the monitoring site. The correlation coefficient for radon concentration in spring water with minimum and maximum relative humidity was 0.4. Spring water radon concentration was found positively correlated (0.6) with water discharge rate of the spring. A weak correlation (0.09) was observed between the radon concentration in spring water and rain fall during the measurement period. As temperature of near surface soil increases, the radon emanation coefficient from the soil surface also increases. The possible effects due to global warming and other climatic changes on environment radiation level were also discussed in detail.Yogesh Prasad1, Ganesh Prasad1, G S Gusain1, V M Choubey2 and R C Ramola1* 1Department of Physics, H N B Garhwal University, Badshahi Thaul Campus, Tehri Garhwal-249 199, Uttarakhand, India 2Wadia Institute of Himalayan Geology, Dehradun-248 001, Uttarakhand, India E-mail : [email protected] of Physics, H N B Garhwal University, Badshahi Thaul Campus, Tehri Garhwal-249 199, Uttarakhand, India Wadia Institute of Himalayan Geology, Dehradun-248 001, Uttarakhand, Indi