Production Cross Sections and Induced Activity in Ge Isotopes by 30 MeV Proton Beam

330-334The excitation functions of 70Ge(p,n)70As,72Ge(p,n)72As, 74Ge(p,n)74As and 76Ge(p,n)76As reactions were studied from reaction threshold to 30 MeV by using EMPIRE-3.2 and TALYS-1.9 nuclear reaction model codes. This study is important because some isotopes produced are important for positron emission tomography (PET). Direct, pre-compound and compound nuclear reactions are considered as main nuclear reaction mechanisms in the codes. The calculated excitation functions have been compared with available experimental data and found to be in fair agreement. Furthermore, the contributions of various reaction mechanisms have been studied in total reaction cross-section that varies with the incident proton energy. The estimation of induced radio activity in thick Ge target due to the primary interaction is carried out for1μA, 30 MeV proton beam

Production Cross Sections and Induced Activity in Ge Isotopes by 30 MeV Proton Beam

The excitation functions of 70Ge(p,n)70As,72Ge(p,n)72As, 74Ge(p,n)74As and 76Ge(p,n)76As reactions were studied from reaction threshold to 30 MeV by using EMPIRE-3.2 and TALYS-1.9 nuclear reaction model codes. This study is important because some isotopes produced are important for positron emission tomography (PET). Direct, pre-compound and compound nuclear reactions are considered as main nuclear reaction mechanisms in the codes. The calculated excitation functions have been compared with available experimental data and found to be in fair agreement. Furthermore, the contributions of various reaction mechanisms have been studied in total reaction cross-section that varies with the incident proton energy. The estimation of induced radio activity in thick Ge target due to the primary interaction is carried out for1μA, 30 MeV proton beam

Conduction Mechanism and Dielectric Properties in Polyaniline/Titanium Dioxide Composites

The conductivity and dielectric properties of polyaniline (PANI) and PANI/TiO2 composites have been studied over a temperature range (313-393 K) and frequency range (25 Hz- 50 MHz). The nature of temperature and frequency-dependent conductivity can be explained by Jonscher’s universal power law and used to find the related parameters such as frequency exponent (s), dc conductivity (σdc), and crossover frequency (ωH). Besides, the frequency exponent analysis through a distinct model suggests that the conduction occurred through small polaron tunnelling in all compositions and at different temperatures. On the other hand, the enthalpy of migration (Hm), dissociation enthalpy of cation from its indigenous location alongside a compensating center (Hf), and the activation energy were also calculated using the Arrhenius relation. The temperature-dependent dc conductivity was examined in the framework of the theoretical model; Mott’s variable range hopping model (VRH) and experimental results were in good agreement with the 3-dimensional VRH model. As a function of temperature, dielectric constants (ε’ and ε”) increase while decreasing with an increasing dopant. Being such a high dielectric constant value, these composites can be used as frequency converters, modulators, and dielectric amplifiers

Polyaniline Chromium Nitrate Composites: Influence of Chromium Nitrate on Conductivity and Thermal Stability of Polyaniline

Thermal stability and electrical conductivity are the key to the technological feasibility and sustainability of conductingpolymers (CPs) and their composites in real-time applications. Notably, the impact of filler loading on above mentionedparameters of CPs needs to be examined and addressed with facile and easily accessible techniques. In the present study,Polyaniline (PANI) /chromium nitrate composites have been prepared via in situ polymerization of aniline through thechemical oxidative polymerization route. After that, the conductivity and thermal stability of PANI have been investigated atdifferent weight percentage loadings of chromium nitrate viz 5, 10, 20, and 40 % in the composite materials.The morphological and structural analysis of the pristine and composite samples were executed with Scanning electronmicroscopy (SEM), Fourier transforms infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) techniques. Thermalanalysis of proposed composites is carried out using the thermogravimetric analysis (TGA) method to evaluate variouskinetic parameters. The TGA thermogram and different calculated parameters revealed that the composites were morethermally stable than pristine PANI and that the composite having 20 wt % of chromium nitrate is thermally the most stable.The DC electrical conductivity data shows that PANI loaded with 20% chromium nitrate has the highest conductivity. Thisincrement in conductivity and thermal stability of the composites opens the path for many applications, such as sensors andelectronics

Cross-sections of 14 MeV neutron induced reactions on some isotopes of chromium, zirconium and tin

216-219Neutron induced reaction cross-sections of the isotopes 52Cr, 53Cr, 90Zr, 91Zr, 92Zr, 94Zr, 116Sn, 118Sn and 120Sn for (n,p), (n,n’), (n,a) and (n, 2n) reactions have been evaluated at 14 MeV. The computations are based on the evaporation model considering the pre-equilibrium emission mechanism under some approximations. The computer codes ALICE-91, NX-1 and SC2N3N have been used. These cross-sections were also computed using the level density formula of Lang and Le Couteur with and without applying pairing energy correction. The compound nucleus theory based on Fermi gas and evaporation model with optical model potential parameters has been used. The neutron, proton and alpha penetrabilities and inverse reaction cross-sections have been computed using the computer code SCAT-2. The computed cross-sections have been compared with the available experimental values and the results are in fairly good agreement

Ethanol production by Kluyveromyces marxianus HM36338: Optimization of fermentation conditions using response surface methodology

630-635Bioethanol interests researchers as the greener alternative to fossil fuels. Fungal strains play a major role in this process. On the other hand, whey disposal in dairy industry is an issue of environmental concern. The cheese whey is a source of ethanol production. Kluyveromyces marxianus HM363381 is one such fungal strain used in ethanol production from crude whey. Here, we studied the process of ethanol production by the above strain and attempted to optimize the fermentation conditions adopting response surface methodology (RSM). A total of 20 fermentation trials were carried out which were produced from RSM with the central composite design using the three parameters, lactose concentration (5-20%), yeast extract (10-60%) and the inoculum size (5-14%). The experimental results were analyzed using analysis of variance (ANOVA) and lack of fit tests. The best operating conditions were found to be 14.14% (w/v) lactose concentration, 9.44 % inoculum size and 59.67 g/L yeast extract by keeping the other variables at their zero level, under which the strain Kluyveromyces marxianus HM363381 produced 59 g/L of ethanol. The results demonstrated a correlation of the experimental data to the dynamic models with high significant values of R2 and, thus, could be useful for scaling up the ethanol production by fermentation of crude whey

Study of structural, electrical and thermal properties of polyaniline/ZnO composites synthesized by in- situ polymerization

This paper reports the structural, electrical and thermal properties of the polyaniline doped with ZnO composites. Conducting polymer composites of polyaniline/zinc oxide (PANI/ZnO) have been synthesized by in-situ polymerization of aniline using various compositions (10, 20, 30, 40, 50 wt %) of ZnO in PANI using ammonium persulphate as an oxidant. The amorphous nature of the composites has been ascertained by the X-ray diffraction. Fourier Transform Infrared (FTIR) spectroscopy confirms the interaction between PANI and dopant. Thermal stability of polymer composites has been analyzed by TGA and corresponding thermal kinetic parameters were calculated using Horowitz-Metzger method. Thermal analysis shows higher thermal stability of PANI/ZnO composites than pure PANI. The surface morphology of these composites was analyzed with Scanning Electron Microscopy (SEM), which also confirms the presence of ZnO in the composites. The dc conductivity behaviour of these composites has also been investigated as a function of temperature and concentration in the temperature range 313-393 K and the results were compared with pure PANI. The dc electrical conductivity of PANI/ZnO composites decreased as the ZnO content increased in PANI but increased with the increase in temperature

Study of structural, electrical and thermal properties of polyaniline/ZnO composites synthesized by <i>in- situ</i> polymerization

456-463This paper reports the structural, electrical and thermal properties of the polyaniline doped with ZnO composites. Conducting polymer composites of polyaniline/zinc oxide (PANI/ZnO) have been synthesized by <i style="mso-bidi-font-style: normal">in-situ polymerization of aniline using various compositions (10, 20, 30, 40, 50 wt %) of ZnO in PANI using ammonium persulphate as an oxidant. The amorphous nature of the composites has been ascertained by the X-ray diffraction. Fourier Transform Infrared (FTIR) spectroscopy confirms the interaction between PANI and dopant. Thermal stability of polymer composites has been analyzed by TGA and corresponding thermal kinetic parameters were calculated using Horowitz-Metzger method. Thermal analysis shows higher thermal stability of PANI/ZnO composites than pure PANI. The surface morphology of these composites was analyzed with Scanning Electron Microscopy (SEM), which also confirms the presence of ZnO in the composites. The dc conductivity behaviour of these composites has also been investigated as a function of temperature and concentration in the temperature range 313-393 K and the results were compared with pure PANI. The dc electrical conductivity of PANI/ZnO composites decreased as the ZnO content increased in PANI but increased with the increase in temperature.</span