Microprocessor controlled low-temperature corn drying system
Abstract Hardware, software and control criteria of microcomputer control of low-temperature corn drying are discussed. The ambient temperature and relative humidity were monitored by the microcomputer as a measure of the input conditions. A model of the low-temperature drying process stored in the memory enabled the microcomputer to calculate the grain moisture contents at assigned locations in the bin. Control decisions were then based on predicted moisture levels and on predicted or measured grain temperatures. Simulation results showed that the proposed system can save energy from 5 to 31% compared with high-temperature drying, depending upon the weather conditions.
Selected aspects of crop processing and storage: a review.
Significant developments and technical trends of the past decade in the area of crop drying, processing and storage are reviewed. In particular, the effects of recent innovations in operational research, computer technology and microelectronics on the energy efficiency, product quality and process economics are assessed. The review concentrates on grain drying, grain storage, hay drying and biomass energy. The sharp increase in energy prices during the 1970s and the requirement for improved product quality have stimulated innovations in grain drying. Significant developments have occurred in high-temperature drying (concurrent-flow and in-bin-counterflow drying) and in lowtemperature drying (solar and chemical-assisted drying). Computer modelling has become a major tool in designing driers. Controlled atmosphere storage is making a revival as a non-chemical grain preservation technique. High nitrogen and high CO2 content systems appear to be economical. Refrigerated aeration also has promise as an alternative method for grain preservation in warm climates. In some parts of the world (e.g. the U.S.A.) hay is becoming of increasing importance as an animal feed. One-day hay harvesting is close to reality through the development of new mechanical and chemical conditioners. Biomass energy has promise as a fossil fuel replacement. The technical feasibility of biomass furnaces has been proven, the economic feasibility remains in question.
DEM generation from new VIR sensors: IKONOS, ASTER and Landsat-7
DEM generation is a living R&D topic since new-launched satellite images can be used to generate stereoscopic images. Using a coplanarity equation model developed at CCRS and an automatic matching method developed at PCI, DEMs are generated with new VIR stereo data. Accuracy of 4.9 m with high-resolution IKONOS images, and 33 m and 101 m with medium-resolution ASTER and Landsat-7 ETM/sup +/ images respectively are obtained. The same matching accuracy of one-pixel is translated into worse results with Landsat due to a small B/H ratio of 0.15.