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This paper presents a structure-property model for carbon fiber derived from a polyethylene (PE) precursor that relates tensile modulus to the elastic properties and angular distribution of constituent graphitic layers, as measured using wide-angle x-ray diffraction of individual carbon fiber filaments. The observed relationship and interpretation of data using a uniform-stress model has revealed fundamental differences in the nature of the microstructure present in carbon fiber produced from polyethylene compared to carbon fiber produced from polyacrylonitrile (PAN) or pitch precursors. Specifically, it was found that the shear modulus, indicative of the shear between adjacent graphitic layers of the carbonized fiber is lower for polyethylene-derived carbon fiber than for PAN- or pitch-derived carbon fiber, suggesting that the covalent C C sp3 crosslink density connecting adjacent graphitic layers in PE-derived carbon fiber is reduced. This structure that is less crosslinked is anticipated to be easier to orient during carbonization and high-temperature graphitization processes, yielding a highly oriented structure necessary for high tensile modulus.

Stratigraphic forward modelling (SFM) has been used to answer important questions in stratigraphic analysis. This has been demonstrated through generic modelling of synthetic data and numerous two-dimensional (2D) real data case studies, but the method has rarely been used to further our understanding of specific, real three-dimensional (3D) carbonate data sets by quantitative comparison. This paper applies CARBONATE-3D, a SFM program, to a hydrocarbon reservoir and outcropping carbonate platforms at both exploration and production scales. We show the value of SFM in the exploration and production of hydrocarbons through predicting facies distributions and stratigraphic geometries between wells, and by analysing and answering fundamental questions about the formation of specific carbonate strata. First, the model is tested using the 3D outcrops of a Miocene attached carbonate platform at Nijar, SE-Spain where 78% of mapped facies are matched in the simulations. Second, SFM of an 80,000 km 2 Jurassic ramp in NE Spain (exploration scale), predicts new facies in areas without data, leads to an improved understanding of ramp evolution, modification of the interpreted sea-level curve and re-interpretation of the main sediment transport direction. Application to the isolated platform reservoir Judy Creek (Devonian, Canada) exemplifies the advantages of applying SFM at reservoir scale. The simulations yield information on platform geometries and facies distributions, an improved understanding of the factors that control platform evolution, and propose a revised sea-level history. Wider applications of SFM in exploration include assessment of the possibilities and probabilities of facies distributions and evaluation and ranking of different interpretations of platform evolution. At the reservoir scale facies probability distributions and layer-geometries derived from SFM can serve as input into static reservoir models to guide geostatistical simulations.

The thermal degradation and light capture performance of CuInGaSe 2 (CIGS) and c-Si photovoltaic devices were explored. Typically thin-film polycrystalline materials such as CIGS are hypothesized to be advantaged over single crystal Si solar cells as having lower thermal performance and improved light capture response. To this end, we present our evaluation of the thermal and light capture performance of three different CIGS devices, having different absorber layer stoichiometry and bandgap (E g ), and a c-Si device. Our results indicate that at the cell level these CIGS and c-Si photovoltaic devices have similar thermal degradation and light capture performance. The thermal performance of the c-Si and three CIGS materials explored were on average 0.40, 0.47, 0.51, and 0.48 % efficiency/°C, respectively. At low light levels (∼150 W/m2) the voltages generated by each device were within 90% of those generated at full light intensity (1000 W/m2). The current levels generated by each device trended linearly with the irradiance, and the Rs for each device increased with the irradiance although no intentional changes were made to the electrical contacts. These results indicate that both CIGS-based and c-Si devices will perform equally well in comparable real-world conditions. With regards to the performance relative to the CIGS bandgap, tuning the CIGS material stoichiometry, i.e. making it closer to CGS, should broaden the materials spectral response and provide beneficial improvements to the thermal degradation rate and the light capture performance of CIGS devices.

In our study, Shell Solar Industries (SSI) minimodules were subjected to dry heat (85°C), damp heat (85°C/100% RH), and anaerobic/aerobic 85°C water baths. After 168 hrs exposure to moisture-containing environments, the SSI power generation decreased by over 50% of that of the original state. Analytical characterization performed before and after the exposure identified degradation of the Al:ZnO and Mo layers as likely device failure routes. To elucidate the observed degradation mechanism, individual Al:ZnO and Mo films were sputtered onto borosilicate glass and exposed to both 85°C/100% RH and a room temperature water bath. After 24 hrs the resistivity and optical transmission of the Al:ZnO films increased significantly following both exposure methods. XPS surface analysis of the films revealed changes in the O to Zn bonding ratio suggesting film hydration may have occurred. In addition, after 48 hours by both exposure methods the Mo films corroded, and the film resistivities increased. Our results show Al:ZnO layer degradation limits the lifetime of CIGSS based PV devices, whereas Mo degradation is considered a non-lifetime-limiting failure.