Design description of the Tangaye Village photovoltaic power system

The engineering design of a stand alone photovoltaic (PV) powered grain mill and water pump for the village of Tangaye, Upper Volta is described. The socioeconomic effects of reducing the time required by women in rural areas for drawing water and grinding grain were studied. The suitability of photovoltaic technology for use in rural areas by people of limited technical training was demonstrated. The PV system consists of a 1.8-kW (peak) solar cell array, 540 ampere hours of battery storage, instrumentation, automatic controls, and a data collection and storage system. The PV system is situated near an improved village well and supplies d.c. power to a grain mill and a water pump. The array is located in a fenced area and the mill, battery, instruments, controls, and data system are in a mill building. A water storage tank is located near the well. The system employs automatic controls which provide battery charge regulation and system over and under voltage protection. This report includes descriptions of the engineering design of the system and of the load that it serves; a discussion of PV array and battery sizing methodology; descriptions of the mechanical and electrical designs including the array, battery, controls, and instrumentation; and a discussion of the safety features. The system became operational on March 1, 1979

Operational performance of the photovoltaic-powered grain mill and water pump at Tangaye, Burkina Faso (formerly Upper Volta)

A photovoltaic (PV) system powering a grain mill and water pump was installed in the remote African village of Tangaye, Burkina Faso (formerly Upper Volta) under the sponsorship of the U.S. Agency for International Development (AID) and by the National Aeronautics and Space Administration (NASA) Lewis Research Center (LeRC) in early 1979. The presence reports covers the second two years of operation from April 1981 through June 1983. During this time, the grain mill and water pump were operational 96 and 88 percent of the time respectively, and the PV system generated sufficient electricity to enable the grinding of about 111 metric tons of finely ground flow and the pumping of over 5000 cm sq of water from the 10 m deep well. The report includes a description of the current configuration of the system, a review of system performance, a discussion of the socioeconomic impact of the system on the villagers and a summary of results and conclusions covering the entire four-year period

Operational performance of the photovoltaic-powered grain mill and water pump at Tangaye, Upper Volta

The first two years of operation of a stand alone photovoltaic (PV) power system for the village of Tangaye, Upper Volta in West Africa are described. The purpose of the experiment was to demonstrate that PV systems could provide reliable electrical power for multiple use applications in remote areas where local technical expertise is limited. The 1.8 kW (peak) power system supplies 120-V (d.c.) electrical power to operate a grain mill, a water pump, and mill building lights for the village. The system was initially sized to pump a part of the village water requirements from an existing improved well, and to meet a portion of the village grain grinding requirements. The data, observations, experiences, and conclusions developed during the first two years of operation are discussed. Reports of tests of the mills used in the project are included

Tunisia Renewable Energy Project systems description report

In 1979, the Agency for International Development (AID) initiated a renewable energy project with the Government of Tunisia to develop an institutional capability to plan and institute renewable energy technologies in a rural area. The specific objective of the district energy applications subproject was to demonstrate solar and wind energy systems in a rural village setting. The NASA Lewis Research Center was asked by the AID Near East Bureau to manage and implement this subproject. This report describes the project and gives detailed desciptions of the various systems

Effects of erosion on soil quality and productivity of a field near Saskatoon

Non-Peer ReviewedSoil erosion has been identified as a major contributor to soil degradation on the Prairies. An 84 ha cultivated watershed near Saskatoon was selected to study the variability in erosion and deposition. 137Cs deposited mainly in the early 1960's was used as a tracer for soil movement. Soil erosion ranged from 35 t/ha/yr in small tributaries to the main channel, to 4 t/ha/yr or less on upper slope areas which occupied 60 % of the area. High rates of soil deposition were found in. upland depressions and in the main channel. The net soil loss from the basin was 2340 t or about 1 t/ha/yr. Seventy to 80% of the lost soil was retained ahead of a dam in the coulee leaving the field. It is estimated that the eroding areas of the field (approximately 77 ha) suffered an organic C loss of 275 t from the early 1960's to mid 1980's. Preliminary estimates indicate that about 215 t of organic C were deposited in the upland depressions and the main channel inside the field boundaries. Estimates of the organic C trapped in the coulee are in the order of 50 to 90 t. Further sampling will be needed to resolve the discrepancy between estimates of organic C lost from the field, and organic C trapped, in the coulee. Based on approximate relationships between soil depth and yield potential, it is expected that the production of about one quarter of the eroding area is adversely affected by erosion when other growing conditions are good

Observations of Extremely Cool Stars

As one part of a program of infrared astronomy carried on at the California Institute of Technology, a survey of the sky in two infrared spectral ranges, 0.68-0.92 μand 2.01- 2.41 μ, is being carried out. The motivation for such a survey is to obtain an unbiased census of objects that emit in the 2.0-2.5-μ atmospheric window; this will, of course, include many ordinary stars, but it might also reveal many potentially interesting objects that would not be included in an a priori selection of objects to be measured. In fact, a number of strikingly red stars have already been found. Since most of these "superred" stars occur in the Milky Way, interstellar reddening may be of some consequence; but in at least a few cases the stars seem to be intrinsically extremely red. These preliminary results seem of sufficient interest to merit brief description at this time

Edaphic and Phytochemical Factors as Predictors of Equine Grass Sickness Cases in the UK

Background: Equine dysautonomia or equine grass sickness (EGS), as it is more commonly known, is a usually fatal disease of equids of uncertain etiology, although associated with grazing, that affects the autonomic and enteric nervous system. Lowered gastrointestinal motility, leading to paralysis of the gut, is one of the main symptoms of EGS. Previous studies have implicated anaerobic bacteria, notably Clostridium botulinum, but what triggers the severe bacterial infestations remains enigmatic. We hypothesized that a detailed comparison of soil mineral and botanical composition of EGS and control sites would yield new insights into the causation of the disease. Results: Between March 2007 and September 2008, soil, plant, and water samples from a total of 23 EGS sites and 11 control sites were studied. Metal and non-metal element levels of the soil and herbage samples were assessed. Significantly, EGS sites had higher levels of soil nitrogen, and significantly higher levels of iron, lead, arsenic, and chromium in the herbage. Toxic Ranunculus spp. (buttercups) were found in abundance at every EGS site, making ingestion plausible. Conversely, neurotoxin-producing cyanobacteria were not found in any of the water samples analyzed. Conclusions: The significantly higher levels of iron and heavy metals found in herbage growing in EGS sites, in addition to toxic Ranunculus species, suggest that previously unknown triggers are involved in a multi-factorial EGS etiology. Our results also show that cyanobacteria on the other hand, are unlikely to be a factor in EGS. Consequently, the concomitant presence of two (or more) factors could be the trigger for an outbreak of EGS