The partial reinforcement effect in a vigilance task
Partial reinforcement effect in visual vigilance task, varying knowledge of results as incentive
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Partial reinforcement effect in visual vigilance task, varying knowledge of results as incentive
A cost study was made to assess the potential of the large-scale use of solar cell power for terrestrial applications. The incentive is the attraction of a zero-pollution source of power for wide-scale use. Unlike many other concepts for low-pollution power generation, even thermal pollution is avoided since only the incident solar flux is utilized. To provide a basis for comparison and a perspective for evaluation, the pertinent technology was treated in two categories: current and optimistic. Factors considered were solar cells, array assembly, power conditioning, site preparation, buildings, maintenance, and operation. The capital investment was assumed to be amortized over 30 years. The useful life of the solar cell array was assumed to be 10 years, and the cases of zero and 50-percent performance deg-radation were considered. Land costs, taxes, and profits were not included in this study because it was found too difficult to provide good generalized estimates of these items. On the basis of the factors considered, it is shown that even for optimistic projections of technology, electric power from large-sclae terrestrial use of solar cells is approximately two to three orders of magnitude more costly than current electric power generation from either fossil or nuclear fuel powerplants. For solar cell power generation to be a viable competitor on a cost basis, technological breakthroughs would be required in both solar cell and array fabrication and in site preparation.
Vigilance experiments have been performed to study the relative efficiency of feedback operations in enhancing vigilance performance. Two feedback operations were compared - i.e., experimenter-controlled feedback in the form of knowledge of results (KR) regarding response times to signal detections, and subject-controlled feedback in the form of self-evaluation (SE) of response times to signal detections. The subjects responded to the aperiodic offset of a visual signal during a 1-hr vigil. Both feedback operations were found to enhance performance efficiency: subjects in the KR and SE conditions had faster response times than controls receiving no evaluative feedback. Moreover, the data of the KR and SE groups did not differ significantly from each other. The results are discussed in terms of the hypothesis that self-evaluation is a critical factor underlying the incentive value of KR in vigilance tasks.
NASA made use of the analytical outputs of reliability people to make management decisions on the Apollo program. Such decisions affected the amount of the incentive fees, how much acceptance testing was necessary, how to optimize development testing, whether to approve engineering changes, and certification of flight readiness. Examples of such analysis are discussed and related to programmatic decisions.-
The contributions of science and technology to the success of the United States as a world leader are discussed. Specific instances of the manner in which science advances and new technologies resulting from space research have contributed to a higher standard of living are presented. It is concluded that the benefits of the space program are not reflected only in the material advancements, but that intangible results have also been achieved in greater incentives to improve the present culture.
Incentives for broadening the present role of civilian nuclear power to include mobile nuclear power plants that are compact, lightweight, and safe are examined. Specifically discussed is the growing importance of: (1) a new international cargo transportation capability, and (2) the capability for development of resources in previously remote regions of the earth including the oceans and the Arctic. This report surveys present and potential systems (vehicles, remote stations, and machines) that would both provide these capabilities and require enough power to justify using mobile nuclear reactor power plants.
Justice Department airline merger policy is developed within the context of the Federal Aviation Act, in which there is an unusually explicit reliance on competition as a means of fulfilling statutory goals. The economics of the airline industry appear to indicate that low concentration and vigorous competition are particularly viable and desirable. Several factors, including existing regulatory policy, create incentives for airlines to merge whether or not an individual merger promotes or conflicts with the public interest. Specific benefits to the public should be identified and shown to clearly outweight the detriments, including adverse competitive impact, in order for airline mergers to be approved.
This paper discusses a project for adapting advanced technology, much of it borrowed from the jet transport, to general aviation design practice. The NASA funded portion of the work began in 1969 at the University of Kansas and resulted in a smaller, experimental wing with spoilers and powerful flap systems for a Cessna Cardinal airplane. Some flight data and research pilot comments are presented. The project was expanded in 1972 to include a light twin-engine airplane. For the twin there was the added incentive of a potential increase in single-engine climb performance. The use of a new high-lift Whitcomb airfoil is planned for both the wing and the propellers. Preliminary data on the characteristics of the new airfoil are discussed. The configuration of an experimental wing for a Piper Seneca PA-34 and estimated airplane performance with this wing are discussed.
The recent energy crisis and subsequent substantial increase in fuel prices have provided increased incentive to reduce the fuel consumption of civil transport aircraft. At the present time many changes in operational procedures have been introduced to decrease fuel consumption of the existing fleet. In the future, however, it may become desirable or even necessary to introduce new fuel-conservative aircraft designs. This paper reports the results of a preliminary study of new near-term fuel conservative aircraft. A parametric study was made to determine the effects of cruise Mach number and fuel cost on the optimum configuration characteristics and on economic performance. For each design, the wing geometry was optimized to give maximum return on investment at a particular fuel cost. Based on the results of the parametric study, a nominal reduced energy configuration was selected. Compared with existing transport designs, the reduced energy design has a higher aspect ratio wing with lower sweep, and cruises at a lower Mach number. It has about 30% less fuel consumption on a seat-mile basis.
Discussion of the basic incentives motivating the development of the short-haul STOL air transportation system. The technological impact on the aircraft and its related economics required to achieve short field performance is generally detrimental. Considerations such as wing and empennage sizing, engine thrust sizing and cycle selection, thrust reverser requirements, cruise Mach number effects, noise, and fuel usage impacts are discussed. The direct operating economics are adversely affected, although it is thought that the indirect costs can be correspondingly reduced. A study of the total operating costs of the short-haul system and its related fare structure indicates that a definite potential exists for the evolution of an economically viable system yielding positive returns on investment to the operators. It is concluded that this potential is sufficient to warrant more detailed studies of these economics and the alternative implementation schemes.
Solar cells may be used to convert sunlight directly into electrical energy and into lowgrade heat to be used for large-scale terrestrial solar-energy conversion. Both forms of energy can be utilized if such cells are deployed in close proximity to the consumer (rooftop). Cadmium-sulfide/copper-sulfide (CdS/Cu2S) solar cells are an example of cells which may be produced inexpensively enough to become economically attractive. Cell parameters relevant for combined solar conversion are presented. Critical issues, such as production yield, life expectancy, and stability of performance, are discussed. Systems-design parameters related to operating temperatures are analyzed. First results obtained on Solar One, the experimental house of the University of Delaware, are given. Economic aspects are discussed. Different modes of operation are discussed in respect to the power utility and consumer incentives.
The principal objective of the present work is to identify a variety of strategic approaches which could significantly enhance the rate of commercial development and deployment of total energy systems, fuel cells, and solar conversion. Emphasis is on the need for integration of research, conference, legislation, federal program, and industrial program aspects, leading to a fruitful feedback and follow-through process involving new energy technologies. The discussions are on a general, lay level. Recommendations made feature (1) action which improves the environment for innovation and change, (2) action which decreases risk and creates positive incentives, and (3) action which reflects the distance a particular technology is from commercialization and widespread use, as determined by its position on a development/diffusion scale.
This paper describes the design and development of a set of multifunction VHF/UHF integrated circuits aimed at providing a major improvement in spacecraft radio reliability through low stress operation and the processing of these circuits in beam-lead form. The methods evolved for the high frequency characterization of the devices are discussed together with the design of suitable test fixtures. Typical test results and the distribution of test parameters are presented. A unique carrier for beam-lead devices is described, and the need for such a device is discussed. The application of the carrier to device screening, burn-in and drift measurements is discussed together with the incentives for providing these capabilities. An overview of the integration of the devices into the spacecraft radio is given and candidate assembly processes are discussed. The technology impact of this approach upon future spacecraft radio systems is qualitatively examined.
Results are presented of a conceptual design and feasibility study of chemical propulsion stages that can serve as modular propulsion units, with little or no modification, on a variety of planetary orbit missions, including orbiters of Mercury, Saturn, and Uranus. Planetary spacecraft of existing design or currently under development, viz., spacecraft of the Pioneer and Mariner families, are assumed as payload vehicles. Thus, operating requirements of spin-stabilized and 3-axis stabilized spacecraft have to be met by the respective propulsion module designs. As launch vehicle for these missions the Shuttle orbiter and interplanetary injection stage, or Tug, plus solid-propellant kick motor was assumed. Accommodation constraints and interfaces involving the payloads and the launch vehicle are considered in the propulsion module design. The applicability and performance advantages were evaluated of the space-storable high-energy bipropellants. The incentive for using this advanced propulsion technology on planetary missions is the much greater performance potential when orbit insertion velocities in excess of 4 km/sec are required, as in the Mercury orbiter. Design analyses and performance tradeoffs regarding earth-storable versus space-storable propulsion systems are included. Cost and development schedules of multi-mission versus custom-designed propulsion modules are examined.
The present status of the energy implications of the transportation systems in the United States was illustrated, with primary emphasis on the technologies and methods for achieving a substantial reduction in the associated energy price (approximately 25% of the nation's energy is consumed directly in the operation of these systems). These technologies may be classified as follows: (1) improvement of system efficiency (system operations or technological), (2) substitution for scarce energy resources (electrification, alternate fuels, use of man power, recycling), (3) curtailment of end use (managed population growth rate, education of citizenry, alternatives to personal transportation, improved urban planning, reduced travel incentives). Examples and illustrations were given. Thirty-four actions were chosen on the basis of a preliminary filtering process with the objective of: (1) demonstrating a methodological approach to arrive at logical and consistent conservation action packages, (2) recommending a viable and supportable specific set of actions.
The requirements of the electric utility industry as the primary potential market for geothermal energy are analyzed, based on a series of structured interviews with utility companies and financial institution executives. The interviews were designed to determine what information and technologies would be required before utilities would make investment decisions in favor of geothermal energy, the time frame in which the information and technologies would have to be available, and the influence of the governmental politics. The paper describes the geothermal resources, electric utility industry, its structure, the forces influencing utility companies, and their relationship to geothermal energy. A strategy for federal stimulation of utility investment in geothermal energy is suggested. Possibilities are discussed for stimulating utility investment through financial incentives, amelioration of institutional barriers, and technological improvements.
In the manufacture of cement, literally trillions of Btu's are rejected to the environment each year. The purpose of this feasibility study program was to determine whether thermal energy storage could be used to conserve or allow alternative uses of this rejected energy. This study identifies and quantifies the sources of rejected energy in the cement manufacturing process, established use of this energy, investigates various storage system concepts, and selects energy conservation systems for further study. Thermal performance and economic analyses are performed on candidate storage systems for four typical cement plants representing various methods of manufacturing cement. Through the use of thermal energy storage in conjunction with waste heat electric power generation units, an estimated 2.4 x 10 to the 13th power Btu/year, or an equivalent on investment of the proposed systems are an incentive for further development.
A parallel-burn version of a single-stage vehicle for transport from the earth to low-earth orbit using two fuels and rocket propulsion is considered. New engine results were incorporated in vehicle performance and design studies. The results indicate that a hydrogen-cooled gas generator cycle engine provides attractive vehicle performance and that there is little incentive for increasing the chamber pressure beyond 27 MPa.