MASS ATTENUATION COEFFICIENT AND ATOMIC CROSS SECTION OF GeO2 IN THE ENERGY RANGE 122-1330KeV

In the present investigation, we have determined here the mass attenuation coefficients (μm) of germanium oxide for energies of 122 -1330 keV. Photon energies are measured using the different radioactive sources Co57, Ba133, Cs137, Na22, Mn54 and Co60. In the current investigation to detect gamma rays NaI(Tl) scintillation detection system were used. The investigated attenuation coefficient values were then used to determine the important parameters i.e. total atomic cross sections (st) for germanium oxide. Graphically it is observed that the variations of μm and st with energy The values of μm, st, are higher at lower energies and they decrease sharply as energy increases. The XCOM data is used to calculate Theoretical values. We were observed that the Theoretical and experimental values are found to be in a good agreement (error < 3-4%)

EFFECTS OF GAMMA-RADIATION ON POLY ISOBUTYLENE

Radiological parameters such as Mass attenuation coefficient (μm), effective atomic numbers (Zeff), electron densities (Neff), total cross-section (σt) & electronic cross-section (σe) have been computed and investigated for poly-isobutylene using NaI (Tl) scintillation counter and XCOM program. The gamma ray photons were detected by using NaI (Tl) detector with resolution of 8.2 % at 662 keV, using radioactive gamma ray sources 57Co, 133Ba, 137Cs, 54Mn, 60Co and 22Na. Values of μm for the poly-isobutylene decrease with increasing energy. An experiment is done to avail the radiological data on poly- isobutylene and to check the effects of gamma radiation produced on material with different energy ranges. It is found from the present investigation that the investigated results found immense importance in radiation industry, dosimetry, polymer industry etc

Solar driven two-step CH4 reforming and H2O splitting using Al2O3 for Co-production of Al, syngas, and H2

The thermodynamic equilibrium and efficiency analysis of the solar-driven Al2O3-based CH4 reforming and H2O splitting process is performed in two sections: (1) Al and syngas producing open process (AS), and (2) Al, syngas, and H2 producing semi-open process (ASH). The equilibrium analysis indicate that with the rise in the CH4/Al2O3 molar ratio, formation of Al and syngas (via methanothermal reduction of Al2O3) improves and reaches its maximum value at 2530 K (in case of CH4/Al2O3 molar ratio = 3). The efficiency analysis (for both cycles) is carried out at a steady thermal reduction temperature (TH) equal to 2530 K. In case of the ASH process, the water-splitting reactor is employed for the production of H2 and the effect of water splitting temperature (TL) on the process efficiency values is explored. Obtained results shows that the solar-to-fuel energy conversion efficiency in case of the ASH process is higher as compared to the AS process. Furthermore, this efficiency (in case of the ASH process) can be increased up to 50.7% via heat recuperation.This publication was made possible by the NPRP grant ( NPRP8-370-2-154 ) from the Qatar National Research Fund (a member of Qatar Foundation)

Thermodynamic efficiency analysis of zinc oxide based solar driven thermochemical H2O splitting cycle: Effect of partial pressure of O2, thermal reduction and H2O splitting temperatures

In this paper, the thermodynamic efficiency analysis of ZnO-based solar-driven thermochemical H2O splitting cycle is performed and compared with the SnO2-based H2O splitting cycle. The HSC Chemistry 7.1 software is used for this analysis and effects of thermal reduction (TH) and water splitting temperature (TL) on various thermodynamic parameters associated with the ZnO-based H2O splitting cycle are explored. The thermodynamic equilibrium compositions allied with the ZnO reduction and re-oxidation of Zn via H2O splitting reaction are identified by varying the TH, TL, and PO2 in the inert gas. The efficiency analysis indicates that the highest cycle and solar-to-fuel energy conversion efficiency equal to 41.1 and 49.5% can be achieved at TH = 1340 K and TL = 650 K. Both efficiencies can be increased further by more than 10% via employing heat recuperation (50%). Based on the cycle and solar-to-fuel energy conversion efficiency values, the ZnO-based H2O splitting cycle seems to be more attractive than SnO2-based H2O splitting cycle. ? 2018 Hydrogen Energy Publications LLCThis publication was made possible by the NPRP grant ( NPRP8-370-2-154 ) from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of author(s)

Mn-ferrite based solar thermochemical water splitting cycle: A thermodynamic evaluation

By utilizing the data obtained from the HSC Chemistry software, the thermodynamic equilibrium and efficiency analysis of the Mn-ferrite based water splitting (MFWS) cycle was conducted. All the thermodynamic calculations were performed by varying the partial pressure of O2 (PO2), thermal reduction (TH), and water splitting temperature (TL). The degree of non-stoichiometry (?) allied with the Mn-ferrite was observed to be increased as the PO2 was decreased from 10?1 to 10?5 atm and the TH was upsurged from 1500 to 2100 K. This rise in the ? resulted into a higher amount of H2 production via water splitting (WS) reaction. To achieve upper ?, elevated TH was required and hence the solar energy required to run the MFWS cycle (Q?solar-cycle) was observed to be higher. In contrast, as the TL was increased, due to the drop in the temperature gap between the TH and TL, the Q?solar-cycle was reduced. The solar-to-fuel energy conversion efficiency (?solar-to-fuel) of the MFWS cycle was observed to be maximum when the PO2 and TH were lowest and the TL was the highest. For instance, at PO2 = 10?5 atm, TH = 1500 K, and TL = 1400 K, the uppermost ?solar-to-fuel = 39.8% was attained in case of MFWS cycle which was higher than Ni-ferrite based water splitting (NFWS) cycle by 8.5%. - 2019 Elsevier LtdThis publication was made possible by the NPRP Grant ( NPRP8-370-2-154 ) from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of author(s).Scopu

Synthesis and characterization of nanocrystalline CoFe2O4-zirconia via propylene oxide aided sol-gel method

In this study, a Co ferrite/ZrO2 ceramic nanomixture, with a uniform distribution of Co ferrite and ZrO2, was synthesized by the propylene-oxide-assisted sol gel method. Cobalt, iron, and zirconium nitrate salts were used as the metal precursors, and ethanol and propylene oxide were used as the solvent and gelation agent, respectively. The prepared gels were aged, dried, and annealed at different temperatures (600 1000 C) and times (1 5 h). The annealed Co ferrite/ZrO2 powder was analyzed by powder X-ray diffraction (PXRD), Brunauer Emmett Teller surface area analysis, energy-dispersive spectroscopy (EDS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The PXRD and EDS results indicated that the phase and chemical composition of the Co ferrite/ZrO2 ceramic nanomixture synthesized by the sol gel method is not affected by the annealing temperature and time. The crystallite size of the Co ferrite/ZrO2 ceramic nanomixture increased with the increase in the annealing temperature and time. In contrast, the specific surface area and pore volume decreased with the increase in the annealing temperature and time. SEM/EDS and TEM analysis confirmed the nanoparticulate morphology of the Co ferrite/ZrO2 ceramic nanomixture, with a uniform distribution of Co ferrite and ZrO2.This publication was made possible by the NPRP grants ( NPRP8-370-2-154 ) from the Qatar National Research Fund (a member of Qatar Foundation ). The statements made herein are solely the responsibility of author(s)

Application of cobalt incorporated Iron oxide catalytic nanoparticles for thermochemical conversion of CO2

This investigation describes the application of the sol-gel synthesized CoxFe3?xO4 (CF) materials towards the solar thermochemical fuel production. The CF materials were derived by sol-gel method (where x was varied in the range of 0.2 to 1) and the prepared CF materials were further characterized using multiple analytical techniques. The characterization results specify formation of CF nanoparticles with phase pure composition and high SSA. A high temperature thermogravimetric analyzer (TGA) was employed to determine the redox reactivity of the CF materials towards CO2 splitting reaction. The obtained experimental findings showed that the incorporation of CO+2 into iron oxide crystal structure was advantageous to accomplish higher CO production rate via CO2 splitting. The highest amount of CO production was observed in case of CoFe2O4 (145.2 ?mol/g of CO). It was further realized that the CoFe2O4 possess better CO2 splitting ability in comparison to the Fe3O4 and CeO2. - 2019 Elsevier B.V.This publication was made possible by the NPRP grant ( NPRP8-370-2-154 ) from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of author(s).Scopu

H2 Production via ferrite based H2O splitting cycle: Solar reactor thermodynamic efficiency analysis

This study reports the thermodynamic equilibrium and efficiency analysis of the Ba-ferrite based thermochemical water splitting cycle. Attempts were made to identify the equilibrium composition associated with the thermal reduction of Ba-ferrite using HSC Chemistry software. In addition, the equations associated to the thermodynamic efficiency analysis were developed. Copyright American Institute of Chemical Engineers.This publication was made possible by the NPRP grant (NPRP8-370-2-154) from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of author(s).Scopu

Nanostructured co-precipitated Ce0.9Ln0.1O2 (Ln = La, Pr, Sm, Nd, Gd, Tb, Dy, or Er) for thermochemical conversion of CO2

The influence of lanthanide metal cations doped into the CeO2 crystal structure (to form Ce0.9Ln0.1O2; Ln = La, Pr, Nd, Sm, Gd, Tb, Dy, or Er) on thermochemical reduction and the CO2 splitting ability of Ce0.9Ln0.1O2 is scrutinized using thermogravimetric analysis. Ce0.9Ln0.1O2 redox materials are effectively synthesized by co-precipitation of hydroxides. As-synthesized Ce0.9Ln0.1O2 redox materials are further characterized based on their phase composition, crystallite size, surface area, and morphology using powder X-ray diffraction, Brunauer-Emmett-Teller surface area analysis, and scanning electron microscopy. The thermal reduction and CO2 splitting aptitude of Ce0.9Ln0.1O2 redox materials are examined by performing 10 consecutive thermochemical cycles. The results imply that insertion of Sm3+, Er3+, Tb3+, Dy3+, and La+3 in place of Ce4+ in the fluorite crystal structure of CeO2 (forming Ce0.9Ln0.1O2) enhances the O2 liberation by 22.5, 14.6, 12.6, 5.85, and 2.96 ?mol O2/g?cycle, respectively. Besides, CeLa is observed to be more active towards the CO2 splitting reaction than CeO2 and the other Ce0.9Ln0.1O2 redox materials investigated in this study.This publication was made possible by the NPRP grant ( NPRP8-370-2-154 ) from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of author(s)

Enhancing the production of biogas through anaerobic co-digestion of agricultural waste and chemical pre-treatments

Large amounts of agricultural solid wastes (ASWs) and animal dung are produced annually causing serious environmental problem that requires proper treatment. The present study proposes a strategy for optimizing the anaerobic co-digestion of ASWs and cow dung (CD), identifies the key factors governing the co-digestion performance and evaluates the effect of NaHCO3 alkalinity treatment on improving the economy and performance of anaerobic digestion (AD). The results revealed that the highest cumulative methane production (CMP) of 297.99 NL/kgVS can be generated by co-digestion of ASWs and CD at a ratio of 60:40. Further improvement was achieved via alkalinity treatment with 1.0 g of NaHCO3/gVS leading to decrease in lignin, cellulose, and hemicellulose contents of feedstock by 3.5%, 10.5% and 15.9%, respectively, converting them to soluble fractions and improving the CMP by 11.2–29.7% based on substrate quality. The improved CMP in the chemically treated substrates reflects a 19% increase in the generated revenue. The kinetics of the AD process was successfully fitted to modified Gompertz model with very low standard deviation residuals (SDR) ≤ 5.21 and R2 ≥ 0.979. Results confirm that the proposed strategy is an effective method for producing biogas from co-digestion of ASWs and CD.Scopu