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Agriculture in developed countries is produced under heavily subsidized insurance. The pricing of these insurance contracts, termed premium rates, directly influences farmers profits, their financial solvency, and indirectly, global food security. Changing climate and technology have likely caused significant shifting of mass in crop yield distributions and, if so, has rendered some of the historical yield data irrelevant for estimating premium rates. Insurance is primarily interested in lower tail probabilities and as such the detection of structural change in tail probabilities or higher moments is of great concern for the efficacy of crop insurance programs. We propose a test for structural change with an unknown break(s) which has power against structural change in any moment and can be tailored to a specific range of the underlying distribution. Simulations demonstrate better finite sample performance relative to existing methods and reasonable performance at identifying the break. The asymptotic distribution is shown to follow the Kolmogorov distribution. Our proposed test finds structural change in most major U.S. field crop yields leading to significant premium rate differences. Results of an out-of-sample premium rating game indicate that incorporating structural change in crop yields leads to more accurate premium rates. [ABSTRACT FROM AUTHOR]

Three vanadium-based catalysts were used to remove high concentrations of nitrogen oxides, and the catalysts' performance of de-NOx and anti-H2O under the high concentrations of NOx were investigated. The V-Mo-W/TiO2 catalysts were tested under 1500 mL/min gas flow (GHSV = 500 h−1, 2.4% NO2, 4.78% NH3, 13% O2, 4% H2O, 5% CO2) and characterized by BET, SEM, EDS, XRD, XPS, H2-TPR, and NH3-TPD; then, their physical and chemical properties were analyzed. The results showed that under the influence of H2O, the NOx conversion of the V-Mo-W/TiO2 catalysts remained above 97% at 200–280 °C indicating that the catalysts had high catalytic activity and strong water resistance. The analysis of the characterization results showed that the larger specific surface area of the catalyst, the higher acid content, stronger redox ability, and higher V4+ and V3+ content were the reasons for the high NOx conversion. The surface area decreased and the microstructure become smoother after the reaction, which may be caused by thermal sintering, but the overall morphology did not change. Comparing the H2-TPR and NH3-TPD of V1.6Mo1.7W1.8/TiO2 before and after NH3-SCR reaction, it was found that the reduction peak and the intensity of the acid sites of the sample had not changed, which indicated that the catalyst had good anti-sintering performance and a long lifetime. This is significant for followup long-term engineering application experiments. [ABSTRACT FROM AUTHOR]