Technical Retrofit and Energy-saving Effect on Automatic Control System for High-pressure Feed-and Back-water Circulation
In order to improve operation characteristics of control system for high-pressure feed-and back-water circulation so as to achieve energy-saving purpose,a self-driven multifunctional circumference valve has been developed.Integrating 4 control functions such as the flux induction,backflow prevention,by-pass control and multi-stage pressure reduction,the valve makes previously complicated by-pass system reasonably simplified and the jump adjustment gentled,which helps to keep normal operation of relevant pumps and therefore achieve purposes of energy-saving and safety operation.Analysis results and application practice prove the valve to be satisfactory in reaching various technical and economical indexes.
The study of closed ecological systems (CES) has wide implications for study of ecological interactions both on earth and in space. Our design problem was to create closed ecological systems that were able to support animal grazer populations for greater than thirty days. CES were developed for freshwater and marine systems, in 75 mL Tissue culture flasks. Systems were studied under various influences, such as different light levels, and after the introduction nutrients into the systems. Results from saltwater systems observed under varying light levels suggest that six hours of light per day was adequate and longer light periods were not beneficial. Results from the nutrient introduction experiment indicate that nitrogen was a limiting factor in the health and survival of Daphnia in freshwater CES, but phosphorus was not.