Substantial progress has been made towards implementing all of the prescribed studies and satisfying the stated objectives since the Oil Shale Rehabilitation Project was actively initiated in June 1976. Concurrent with implementation, research objectives were substantively defined and supplemented without distracting or departing from the original purpose. Current studies are designed to fill voids in the present status of knowledge regarding lands disturbed by an impending oil shale industry in Colorado. The efforts of all contributing investigators have therefore been integrated and directed toward the goal of developing methodologies requisite for restoring diverse and complex ecosystems which will require only a minimal amount of maintenance or input of scarce resources. An intensive study site southeast of the Oil Shale Tract C-a has been obtained through a Cooperative Agreement with the Bureau of Land Management. Following this agreement, most subprojects were initiated at the intensive site. Additional programs will be implemented as spent shale becomes available this summer. Studies conducted principally in the laboratory and greenhouse, such as the microbiological and plant genetic studies, have achieved significant results.

This report describes work to conduct several investigations of thin-film polycrystalline solar cells. (1) An analysis of high-efficiency solar cells fabricated at the University of South Florida showed significant reduction in forward recombination current, and the cells were stable over a 3-month test period. (2) Transient voltage effects were documented in a large number of polycrystalline cells and were attributed to long-lived trapping states sensitive to voltage changes near one-half open-circuit voltage. (3) Collection efficiency and its voltage dependence were carefully calculated. The typical effect on photocurrent at operating voltages is about 2% for CuInSe{sub 2}, and less for other cells.