6,431 research outputs found
Photovoltaic system costs using local labor and materials in developing countries
The use of photovoltaic (PV) technology in countries that do not presently have high technology industrial capacity was investigated. The relative cost of integrating indigenous labor (and manufacturing where available) into the balance of the system industry of seven countries (Egypt, Haiti, the Ivory Coast, Kenya, Mexico, Nepal, and the Phillipines) was determined. The results were then generalized to other countries, at most levels of development. The results of the study imply several conclusions: (1) the cost of installing and maintaining comparable photovoltaic systems in developing countries is less than in the United States; (2) skills and some materials are available in the seven subject countries that may be applied to constructing and maintaining PV systems; (3) there is an interest in foreign countries in photovoltaics; and (4) conversations with foreign nationals suggest that photovoltaics must be introduced in foreign markets as an appropriate technology with high technology components rather than as a high technology system
Utilization of solar energy in developing countries: Identifying some potential markets
The potential use of solar electricity generated from photovoltaic cells is examined for nineteen developing nations. Energy and economic profiles are summarized for each country. A comparison is made between the use of autogeneration and photovoltaics in a rural area of Haiti
A digital simulation of message traffic for natural disaster warning communications satellite
Various types of weather communications are required to alert industries and the general public about the impending occurrence of tornados, hurricanes, snowstorms, floods, etc. A natural disaster warning satellite system has been proposed for meeting the communications requirements of the National Oceanic and Atmospheric Administration. Message traffic for a communications satellite was simulated with a digital computer in order to determine the number of communications channels to meet system requirements. Poisson inputs are used for arrivals and an exponential distribution is used for service
Impact of Balance Of System (BOS) costs on photovoltaic power systems
The Department of Energy has developed a program to effect a large reduction in the price of photovoltaic modules, with significant progress already achieved toward the 1986 goal of 50 cents/watt (1975 dollars). Remaining elements of a P/V power system (structure, battery storage, regulation, control, and wiring) are also significant cost items. The costs of these remaining elements are commonly referred to as Balance-of-System (BOS) costs. The BOS costs are less well defined and documented than module costs. The Lewis Research Center (LeRC) in 1976/77 and with two village power experiments that will be installed in 1978. The costs were divided into five categories and analyzed. A regression analysis was performed to determine correlations of BOS Costs per peak watt, with power size for these photovoltaic systems. The statistical relationship may be used for flat-plate, DC systems ranging from 100 to 4,000 peak watts. A survey of suppliers was conducted for comparison with the predicted BOS cost relationship
LOCALIZED REVENUE IMPLICATIONS OF SEVERE TORNADO OUTBREAKS ON THE LODGING INDUSTRY
In 2011, significant tornado outbreaks occurred throughout the United States. The property damage from these tornadoes was record breaking at over $28 billion. The impact of these tornadic events on the lodging industry, however, was not as extreme and in some instances was financially beneficial. This study evaluated the revenue implications of severe tornado events on the lodging industry. Using data provided by the National Oceanic and Atmospheric Administration (NOAA) and Smith Travel Research (STR), the lodging industries of 17 counties impacted by either EF4 or EF5 (enhanced Fujita scale) tornadoes were analyzed. Results indicated that the lodging operations in all 17 counties experienced an occupancy percentage increase for multiple days after tornado events. Only five counties experienced significant increases in average daily rate (ADR) for seven days following tornado events. All but one county experienced increases in revenue per available room (RevPAR) following tornado events. This suggests that gains in RevPAR were influenced more by increased occupancy opposed to inflated room rates
Compendium of Applications Technology Satellite user experiments
The achievements of the user experiments performed with ATS satellites from 1967 to 1973 are summarized. Included are fixed and mobile point to point communications experiments involving voice, teletype and facsimile transmissions. Particular emphasis is given to the Alaska and Hawaii satellite communications experiments. The use of the ATS satellites for ranging and position fixing of ships and aircraft is also covered. The structure and operating characteristics of the various ATS satellite are briefly described
Bubble formation during the collision of a sessile drop with a meniscus
The impact of a sessile droplet with a moving meniscus, as encountered in
processes such as dip-coating, generically leads to the entrapment of small air
bubbles. Here we experimentally study this process of bubble formation by
looking through the liquid using high-speed imaging. Our central finding is
that the size of the entrapped bubble crucially depends on the location where
coalescence between the drop and the moving meniscus is initiated: (i) at a
finite height above the substrate, or (ii) exactly at the contact line. In the
first case, we typically find bubble sizes of the order of a few microns,
independent of the size and speed of the impacting drop. By contrast, the
bubbles that are formed when coalescence starts at the contact line become
increasingly large, as the size or the velocity of the impacting drop is
increased. We show how these observations can be explained from a balance
between the lubrication pressure in the air layer and the capillary pressure of
the drop
Photovoltaic power systems for rural areas of developing countries
Systems technology, reliability, and present and projected costs of photovoltaic systems are discussed using data derived from NASA, Lewis Research Center experience with photovoltaic systems deployed with a variety of users. Operating systems in two villages, one in Upper Volta and the other in southwestern Arizona are described. Energy cost comparisons are presented for photovoltaic systems versus alternative energy sources. Based on present system technology, reliability, and costs, photovoltaics provides a realistic energy option for developing nations
An application of queueing theory to the design of channel requirements for special purpose communications satellites
Special purpose satellites are very cost sensitive to the number of broadcast channels, usually will have Poisson arrivals, fairly low utilization (less than 35%), and a very high availability requirement. To solve the problem of determining the effects of limiting C the number of channels, the Poisson arrival, infinite server queueing model will be modified to describe the many server case. The model is predicated on the reproductive property of the Poisson distribution
Cost performance satellite design using queueing theory
The Poisson arrival model was used to determine the effects of limiting the number of channels for a disaster warning satellite. State probabilities and delay probabilities were estimated for several values of the number of channels (C) for arrival and service rates obtained from disaster warnings issued by the National Weather Service. The results predicted by the queueing model were compared with the results of a digital computer simulation
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