This study is focused on the statistical characterization of live load effects on bridges using weigh-in-motion data from a Mexican highway. A truck load model that is simpler than the design truck model implemented in the current Mexican requirements is suggested for design. The statistics are employed in target-reliability based calibration and verification of load factors in Mexican bridge design. Suggestions that could be useful for the Canadian bridge engineering practice are included.

Recent advances in Cu2ZnSn(S,Se)4 (CZTSe) thin film photovoltaics open the possibility for the future industrialization of this technology. Nevertheless, major progresses in CZTSe have been achieved using conventional thermal processing annealing routes (CTP), which rely on timeconsuming processes with tubular furnaces, incompatible with the requisites of fast methodologies for the Industry. Changing from conventional to rapid thermal processes (RTP) using halogen lamps as heating method is not at all obvious, since the system becomes kinetically controlled, and the CZTSe formation mechanisms as well as crystallization pathways can drastically change. In this work we present the transfer of our kesterite production baseline (Cu2ZnSnSe4:Ge) from a conventional thermal process using a tubular furnace, towards a rapid thermal process using an adapted system, by comparing them and analyzing the differences between both processes in terms of formation mechanisms as well as photovoltaic absorber properties. For this purpose, the rapid annealing process is stopped at different steps, analyzing the compositional, structural and morphological properties of the CZTSe absorber at these different stages. Using a combination of XRF, SEM, Raman spectroscopy and XRD characterization techniques it is demonstrated that in contrast to CTP routes, when RTP is used, kesterite is being formed in large amounts in the very early stages. This suggests a fast formation of CZTSe promoted by the higher Se vapor pressure that can be quickly achieved with this methodology. The formation of kesterite seems to proceed via two competitive reactions (binaries vs ternary compound). Additionally, the fast reaction observed in the system avoids the possible Sn-loss in an efficient way. Through the optimization of this RTP treatment a device with 8.3% efficiency has been obtained (the total time of the thermal process is 12 min), comparable with the efficiencies obtained so far with CTP routes. Finally, the consequences of all these changes for the future interpretation of the formation reaction mechanisms of kesterites are discussed.

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Hetero-junction kesterite Cu 2 ZnSn(S,Se) 4 solar cells with low bandgap obtained from three different methods of fabrication were exposed to red light illumination, and the changes observed in their electronic properties due to this exposure were studied via open circuit voltage transients, admittance spectroscopy, capacitance voltage profiling techniques, and SCAPS simulation fits to experimental data. The results from the aforementioned techniques, in combination with temperature-dependent current voltage analysis, can be used to reveal the dominant Shockley-Read-Hall recombination path at open circuit voltage. We also derived analytical expressions for the activation energy of the saturation current density and the diode quality factor for the specific case of a solar cell device that has no type inversion at the absorber/buffer interface and is limited by interface recombination in the open circuit condition. It is found that the dominant recombination pathway for the low bandgap Cu 2 ZnSn(S,Se) 4 solar cells under consideration is located in the space charge region and not at the absorber/buffer interface.

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