Tracking solar energy concentrating system having a circular primary reflector and a tracking secondary compound parabolic reflector

The present invention relates to an improved solar energy concentrating system and to a preferred novel focal collection zone for such a system. In general, the system comprises a moveable solar energy collector supported above a cylindrically arcuate solar energy concentrating reflector. The solar energy collector has a compound parabolic non-imaging shape. In a preferred embodiment, instead of positioning the collector to rotate about the center of curvature of the reflector and to extend down halfway between the center of curvature and the reflector, in the present invention, the solar energy collector extends further down according to a particular algorithm.     

Nutrition and physical activity program to attenuate obesity and promote physical and metabolic fitness in elementary school children

Obesity and low levels of physical and metabolic fitness are risk factors for cardiovascular disease and diabetes. The purpose of this investigation was to attenuate obesity and improve physical and metabolic fitness in elementary school children. Schools have the opportunity, mechanisms, and personnel in place to deliver nutrition education, fitness activities, and a school food service that is nutritious and healthy. Cohorts from grades 3 to 5 in two school districts in rural Nebraska (Intervention/Control) participated in a 2-year study of physical activity and modified school lunch program. Data collection for aerobic capacity, body composition, blood chemistry, nutrition knowledge, energy intake, and physical activity was at the beginning and end of each year. Int received enhanced physical activity, grade specific nutrition education, and a lower fat and sodium school lunch program. Con continued with a regular school lunch and team sports activity program. At year 2, Int lunches had significantly less energy (9%), fat (25%), sodium (21%), and more fiber (17%). However, measures of 24-hour energy intake for Int and Con showed significant differences for sodium only. Physical activity in the classroom was 6% greater for Int compared to Con (p < 0.05) but physical activity outside of school was approximately 16% less for Int compared to Con (p < 0.05). Body weight and body fat were not different between schools for normal weight or obese children. No differences were found for cholesterol, insulin, and glucose; however, HDL cholesterol was significantly greater and cholesterol/HDL was significantly less for Int compared to Con (p < 0.05). It appears that compensation in both energy intake and physical activity outside of school may be responsible for the lack of differences between Int and Con.     

Flow enforcement algorithms for ATM networks

Four measurement algorithms for flow enforcement in asynchronous transfer mode (ATM) networks are presented. The algorithms are the leaky bucket, the rectangular sliding window, the triangular sliding window, and the exponentially weighted moving average. A comparison, based partly on teletraffic theory and partly on signal processing theory, is carried out. It is seen that the time constant involved increases with the increasing burstiness of the connection. It is suggested that the RMS measurement bandwidth be used to dimension linear algorithms for equal flow enforcement characteristics. Implementations are proposed on the block diagram level, and dimensioning examples are carried out when flow enforcing a renewal-type connection using the four algorithms. The corresponding hardware demands are estimated aid compared     

Combined chemical analyses and biomonitoring at Avedoere wastewater treatment plant in 2002.

Influent--effluent monitoring by comprehensive chemical analyses was conducted at the Avedoere wastewater treatment plant (WWTP) during 2002. In one programme, the same samples were tested for algal toxicity by the ISO 8692 method. Based on evaluation of 17 hazardous substances (including 7 heavy metals), there was a quite good agreement between calculated and measured toxic units. In another programme, influent--effluent monitoring for 11 pharmaceuticals and specific hormones showed high removal rates, except for sulphamethizol and furosemide. High removal is probably due to WWTP operation with long SRTs. Effluent biomonitoring of freshwater mussels showed only bioaccumulation for: diethylphthalate, LAS, EOX as well as Cr and Ni. Surprisingly, no bioaccumulation could be observed for 100 other specific organic compounds and 8 other heavy metals (including Hg, Cd and Pb).