Iron ore-carbon briquette is often used as the feed material in the production of sponge iron via coal-based direct reduction processes. In this article, an experimental and simulation study on the reduction behavior of a briquette that is made by hematite and devolatilized biochar fines under CO-CO 2 atmosphere was carried out. The reaction model was validated against the corresponding experimental measurements and observations. Modeling predictions and experimental results indicated that the CO-CO 2 atmosphere significantly influences the final reduction degree of the briquette. Increasing the reduction temperature did not increase the final reduction degree but was shown to increase the carbon that was consumed by the oxidative atmosphere. The influence of the CO-CO 2 atmosphere on the briquette reduction behavior was found to be insignificant in the early stage but became considerable in the later stage; near the time of the briquette reaching its maximum reduction degree, both iron oxide reduction and metallic iron re-oxidation were able to occur.

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Test case generation is an important task during software testing. In this paper, we present a new test-case generation framework for C programs. This approach combines dataflow analysis and dynamic symbolic execution together, and more importantly, it efficiently searches the program path space for potential faults based on the tabu search strategy and the program fault statistics. Unlike the traditional symbolic execution, which explores the program space exhaustively and is difficult to apply to complicated programs effectively, our approach automatically explores the feasible paths of hidden faults with high probability. The scalable and efficient path search strategy facilitates bug finding with much fewer test cases generated. We implemented this approach, and the experimental results presented in this paper are attractive.

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