PVC-U molding profile extruder control system based on lonworks
By studying the dual-screw profile extruder used in PVC-U molding processing, presents a temperature computer control system in which a combined-control strategy of on-off control, fuzzy-control and integral-control were adaptive elected. The control system used Lonworks constructing a net to regulate the extruder's sub-areas temperature in line. App effect shows that the temperature control precision and the method of multi-subarea control in line with Lonworks filedbus has better effect than those sub-areas self-governed control, and can prevent PVC-U decompounding in the processing effectively, so the character of PVC-U manufacture could be improved.
Application of PLC to Temperature Control System in Extruder
The selection of both plastics material and plastics extrusion machine are very important during plastics extruding.The stability and accuracy of temperature control is extremely important in order to satisfactorily extrude plastics products.A method of temperature control system adopting PID algorithm,PWM(pulse width modulation) theorem based on PLC is dealt with,which is used in plastics extrusion machine.The hardware configuration and technology of software design are also given.The advantage of this method is its accuracy and reliability of temperature controlling.The result shows the overshoot is less than 3℃ and the precision reaches ±1℃ at stable state .
Natural Radioactivity of Intrusive-Metamorphic and Sedimentary Rocks of the Balkan Mountain Range (Serbia, Stara Planina)
Stara Planina (also known as the Balkan mountain range) is known for numerous occurrences and deposits of uranium and associated radionuclides. It is also famous for its geodiversity. The geologic framework is highly complex. The mountain is situated between the latitudes of 43° and 44° N and the longitudes from 22°16′ to 23°00′ E. Uranium exploration and radioactivity testing on Stara Planina began back in 1948. Uranium has also been mined in the zone of Kalna, within the Janja granite intrusive. The naturally radioactive geologic units of Stara Planina are presented in detail in this paper. The main sources of radioactivity on Stara Planina can be classified as: 1. Granitic endogenous—syngenetic–epigenetic deposits and occurrences; 2. Metamorphogenic—syngenetic; and 3. Sedimentary, including occurrences of uranium deposition and fluctuation caused by water in different types of sedimentary rocks formed in a continental setting, which could be classified under epigenetic types. The area of Stara Planina with increased radioactivity (higher than 200 cps), measured by airborne gamma spectrometry, is about 380 square kilometers. The highest values of measured radioactivity and uranium grade were obtained from a sample taken from the Mezdreja uranium mine tailing dump, where 226Ra measures 2600 ± 100 Bq/kg and the uranium grade is from 76.54 to 77.65 ppm U. The highest uranium (and lead) concentration, among all samples, is measured in graphitic schist with high concentrations of organic (graphitic) material from the Inovska Series—99.47 ppm U and 107.69 ppm Pb. Thorium related radioactivity is the highest in granite samples from the Janja granite in the vicinity of the Mezdreja granite mine and the Gabrovnica granite mine tailing dump, and it is the same—250 ± 10 Bq/kg for 232Th, while the thorium grade varies from 30.82 to 60.27 ppm Th. In gray siltstones with a small amount of organic material, the highest radioactivity is related to potassium—2080 ± 90 Bq/kg for 40K.