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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

The Impact of Total Liberalization of Domestic Air Transport on the Social Welfare and on the Dynamic of Competition: Comparison Between the United States and the European Union

Since the lst of April 1997 date of the implementation of the third package of the liberalization, air transport, within the european Union has become totally liberalized. In the United States the deregulation of domestic air traffic was earlier and faster since it took place in October 1978 after the adoption of the only act of deregulation. This paper, in its first part, deals with the liberalization of the industry of air traffic in the european union. After a comparison with US system based on market demand, fare policy and network restrictions, we present our descriptive results coming from treatments on the OAG data. These results present several aspects such as the evolution of the competitive structure of the intra-european routes, the level of airport dominance and the growth of hub structure. The second part of the paper presents models of entry in the airline industry. As profitability" of route flown explains correctly decisions taken by airlines to serve or not a route, the paper focuses on the specification and the estimation of the determinants of city, pair profitability in the european union. Treatments done on the OAG data show a rapid development of leasing space agreement (partial and total) and code sharing practices between 1995 and 2000 in Europe that's why we differentiate first between the two type of competitive strategy of entry(direct entry and leasing space agreement) and second between the competitive strategy of entry and the alliance strategy of code sharing. So the estimation of model will be able to answer the question if the european air transport market is contestable and in case not to see if the decision of entry is more directed by the level of airport dominance (as in the domestic United States market)or essentially by the competitive structure of the routes. We try to explain the nature of entry(directleasing or code sharing) by the different levels of these two determinants.

Zbidi, Karim↗
NASA NTRS2020

Farm-Level Risk Factors of Increased Abortion and Mortality in Domestic Ruminants during the 2010 Rift Valley Fever Outbreak in Central South Africa

Background:Rift Valley fever (RVF) outbreaks in domestic ruminants have severe socio-economic impacts. Climate-based continental predictions providing early warnings to regions at risk for RVF outbreaks are not of a high enough resolution for ruminant owners to assess their individual risk. (2) Methods: We analyzed risk factors for RVF occurrence and severity at the farm level using the number of domestic ruminant deaths and abortions reported by farmers in central South Africa during the 2010 RVF outbreaks using a Bayesian multinomial hurdle framework. (3) Results: We found strong support that the proportion of days with precipitation, the number of water sources, and the proportion of goats in the herd were positively associated with increased severity of RVF (the numbers of deaths and abortions). We did not find an association between any risk factors and whether RVF was reported on farms. (4) Conclusions: At the farm level we identified risk factors of RVF severity; however, there was little support for risk factors of RVF occurrence. The identification of farm-level risk factors for Rift Valley fever virus (RVFV) occurrence would support and potentially improve current prediction methods and would provide animal owners with critical information needed in order to assess their herd’s risk of RVFV infection.

Melinda K Rostel↗
NASA NTRS1973

Water recovery and solid waste processing for aerospace and domestic applications

The work is described accomplished in compiling information needed to establish the current water supply and waste water processing requirements for dwellings, and for developing a preliminary design for a waste water to potable water management system. Data generated was used in formulation of design criteria for the preliminary design of the waste water to potable water recycling system. The system as defined was sized for a group of 500 dwelling units. Study tasks summarized include: water consumption, nature of domestic water, consumer appliances for low water consumption, water quality monitoring, baseline concept, and current and projected costs.

Murawczyk, C.↗
NASA NTRS1973

Evaluation of a multifiltration water reclamation subsystem to reclaim domestic clothes wash water

An evaluation has been performed of a multifiltration water reclamation subsystem to determine its capability to recover water from domestic clothes wash water. A total of 32.89 kg (72.5 lb) of clothes were washed during eight wash cycles which used 1.4 lb of detergent, 145 gallons of hot water and 133.9 gallons of cold water. Water recovered at a weighted average process rate of 3.81 gallons per hour met the majority of the 23 requirements established for potable water by the U.S. Public Health Service. Average power consumed during this evaluation was approximately 71 watt-hours per gallon of water recovered. Filter replacement, which was required primarily for the control of micro-organisms in the recovered water averaged 4.86 filters per 100 gallons of wash water processed. The subsystem removed approximately 98 percent and virtually 100 percent of the phosphates and surfactants, respectively, from the wash water.

Hall, J. B., Jr.↗
NASA NTRS1973

Water recovery and solid waste processing for aerospace and domestic applications. Volume 1: Final report

A comprehensive study of advanced water recovery and solid waste processing techniques employed in both aerospace and domestic or commercial applications is reported. A systems approach was used to synthesize a prototype system design of an advanced water treatment/waste processing system. Household water use characteristics were studied and modified through the use of low water use devices and a limited amount of water reuse. This modified household system was then used as a baseline system for development of several water treatment waste processing systems employing advanced techniques. A hybrid of these systems was next developed and a preliminary design was generated to define system and hardware functions.

Murray, R. W.↗
NASA NTRS1973

Orbital design strategy for domestic communication satellite systems.

Review of some of the considerations pertinent to efficient orbit utilization in the design of domestic communications satellite systems. A strategy is developed to efficiently locate a heterogeneous system of satellites within the available arc and provide room for future growth. A practical design is illustrated, using a computer simulation model, for the placement of 25 satellites within 73% of the available arc employing frequency and polarization coordination techniques. A number of widely variable factors that influence satellite spacing are examined. These factors include such critical system elements as telephony and television interference noise limits, frequency plan coordination, polarization plan coordination, ground antenna diameter, signal protection ratio, and satellite station keeping.

Ramji, S.↗
NASA NTRS1974

The value of improved (ERS) information based on domestic distribution effects of U.S. agriculture crops

The value of improving information for forecasting future crop harvests was investigated. Emphasis was placed upon establishing practical evaluation procedures firmly based in economic theory. The analysis was applied to the case of U.S. domestic wheat consumption. Estimates for a cost of storage function and a demand function for wheat were calculated. A model of market determinations of wheat inventories was developed for inventory adjustment. The carry-over horizon is computed by the solution of a nonlinear programming problem, and related variables such as spot and future price at each stage are determined. The model is adaptable to other markets. Results are shown to depend critically on the accuracy of current and proposed measurement techniques. The quantitative results are presented parametrically, in terms of various possible values of current and future accuracies.

Bradford, D. F.↗
NASA NTRS1975

Future US energy demands based upon traditional consumption patterns lead to requirements which significantly exceed domestic supply

Energy consumption in the United States has risen in response to both increasing population and to increasing levels of affluence. Depletion of domestic energy reserves requires consumption modulation, production of fossil fuels, more efficient conversion techniques, and large scale transitions to non-fossile fuel energy sources. Widening disparity between the wealthy and poor nations of the world contributes to trends that increase the likelihood of group action by the lesser developed countries to achieve political and economic goals. The formation of anticartel cartels is envisioned.

Source record↗
NASA NTRS1977

An economic and performance design study of solar preheaters for domestic hot water heaters in North Carolina

The performance and estimated material costs for several solar preheaters for domestic hot water heaters using isolation levels present in North Carolina are presented. The effects of monthly variations in isolation and the direction of incident radiation are included. Demand is assumed at 13 gallons (49.2 liters) per day per person. The study shows that a closed circulation system with 82 gallons (310 liters) of preheated storage and 53.4 cu ft (4.94 cu m) of collector surface with single cover can be expected to cost about $800 and to repay it capital cost and interest (at 8%) in 5.2 years, assuming present electric rates increase at 5% per year.

Jones, C. B.↗
NASA NTRS1979

Determining potential 30/20 GHZ domestic satellite system concepts and establishment of a suitable experimental configuration

NASA is conducting a series of millimeter wave satellite communication systems and market studies to: (1) determine potential domestic 30/20 GHz satellite concepts and market potential, and (2) establish the requirements for a suitable technology verification payload which, although intended to be modest in capacity, would sufficiently demonstrate key technologies and experimentally address key operational issues. Preliminary results and critical issues of the current contracted effort are described. Also included is a description of a NASA-developed multibeam satellite payload configuration which may be representative of concepts utilized in a technology flight verification program.

Stevens, G. H.↗
NASA NTRS1979

Determining potential 30/20 GHz domestic satellite system concepts and establishment of a suitable experimental configuration

Issues and results in a NASA study of the potential concepts and markets for a multibeam 30/20 GHz domestic satellite system in the 1990s are presented. Issues considered include the reduction of signal attenuation due to rain, beam-beam interference isolation in the multibeam system, the method of access/modulation (FDMA, TDMA or hybrid) and the market for reduced reliability and wideband services. A hypothetical demonstration payload configuration which would attempt to resolve these issues is illustrated. The communications payload would employ a system of seven contiguous coverage spots in order to demonstrate a typical cell in a contiguous beam system having extensive frequency re-use, as in a direct-to-user system, and a single spot, typical of a trunking system, to determine signal isolation. The payload could be carried on several existing buses and is illustrated on an MMS bus.

Stevens, G. H.↗
NASA NTRS1980

An advanced domestic satellite communications system

An updated traffic projection for U.S. domestic satellite communications service covering a period of 15 years; mid-1980 to mid-1995 was prepared. This model takes into account expected technology advances and reductions in transmission costs, legislative and regulatory changes permitting increased competition, and rising energy costs which will encourage more extensive substitution of telecommunications for travel. The historical development and current status of satellite systems are discussed as well as the characteristics of follow-on systems. Orbital arc utilization, spacecraft configuration for single shuttle launch, Earth station configuration, and system costs are examined. Areas which require technology development include multiple beam frequency reuse antennas, on-board switching, intersatellite links, and ka-band operation. Packing and deployment schemes for enclosing the satellite within the shuttle orbiter bay must also be devised.

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NASA NTRS1980

Solar heating and domestic hot water system installed at North Dallas High School

The solar energy system located at the North Dallas High School, Dallas, Texas is discussed. The system is designed as a retrofit in a three story with basement, concrete frame high school building. Extracts from the site files, specification references for solar modification to existing building heating and domestic hot water systems, drawings, installation, operation and maintenance instructions are included.

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NASA NTRS1980

Design package for solar domestic hot water system

The initial design of a solar domestic hot water system is considered. The system performance specification and detailed design drawings are included. The hot water systems consist of the following subsystems: collector, storage, control, transport, auxiliary energy, and government-furnished site data acquisition. The two systems are installed at Tempe, Arizona, and San Diego, California.

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