820,782 research outputs found

    Computer modification reduces time of performing iterative division

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    Time reduction in performing iterative division results from using a serial-by-parallel divider employing a look-ahead feature that predetermines the sign relationships of several iterations before the computer cycle begins. This method can be employed in any data handling system performing high-speed division

    Mechanistic Links Between the Sedimentary Redox Cycle and Marine Acid-Base Chemistry

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    The redox state of Earth's surface is controlled on geological timescales by the flow of electrons through the sedimentary rock cycle, mediated largely by the weathering and burial of Cā€Sā€Fe phases. These processes buffer atmospheric pOā‚‚. At the same time, COā‚‚ influxes and carbonate burial control seawater acidā€base chemistry and climate over long timescales via the carbonateā€silicate cycle. However, these two systems are mechanistically linked and impact each other via charge balance in the hydrosphere. Here, we use a lowā€order Earth system model to interrogate a subset of these connections, with a focus on changes that occur during perturbations to electron flow through the sedimentary rock cycle. We show that the net oxidation or reduction of the Earth's surface can play an important role in controlling acidā€base processes in the oceans and thus climate, and suggest that these links should be more fully integrated into interpretive frameworks aimed at understanding Earth system evolution throughout Precambrian and Phanerozoic time

    Intensification of the freeze drying process by the control of both freezing and primary drying steps

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    The problem of optimization of freeze-drying cycles is addressed, with emphasis in both freezing and primary drying steps. In particular, this study shows that the control of the nucleation event produces more uniform batches (as ice nucleation is induced in all the vials of batch almost at the same time and temperature) and allows a marked reduction in the duration of the optimized cycle (if compared to cycles carried out with conventional stochastic nucleation
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