Atmospheric science facility pallet-only mode space transportation system payload (feasibility study), volume 2
For abstract, see N76-24319.
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Home Page: The Mode of Transport through the Information Superhighway
The purpose of the project with the Aeroacoustics Branch was to create and submit a home page for the internet about branch information. In order to do this, one must also become familiar with the way that the internet operates. Learning HyperText Markup Language (HTML), and the ability to create a document using this language was the final objective in order to place a home page on the internet (World Wide Web). A manual of instructions regarding maintenance of the home page, and how to keep it up to date was also necessary in order to provide branch members with the opportunity to make any pertinent changes.
Lujan, Michelle R.↗
Roles of airships in economic development
It is proposed that airships of known and tested technology could, in some cases, perform routine transport missions more economically than conventional transport modes. If infrastructure for direct surface transport is already in place or if such infrastructure can be justified by the size of the market and there are no unusual impediments to constructing it, then the airships of tested technology cannot normally compete. If, however, the surface routes would be unusually expensive or circuitous, or if they involve several transhipments, or if the market size is too small to spread infrastructure costs of conventional transport, the airships of tested technology present a workable alternative. A series of special cases are considered. The cases, though unusual, are not unique; there are several similar possible applications which, in total, would provide a reasonably large market for airships.
Beier, G. J.↗
Transportation and handling loads
Criteria and recommended practices are presented for the prediction and verification of transportation and handling loads for the space vehicle structure and for monitoring these loads during transportation and handling of the vehicle or major vehicle segments. Elements of the transportation and handling systems, and the forcing functions and associated loads are described. The forcing functions for common carriers and typical handling devices are assessed, and emphasis is given to the assessment of loads at the points where the space vehicle is supported during transportation and handling. Factors which must be considered when predicting the loads include the transportation and handling medium; type of handling fixture; transport vehicle speed; types of terrain; weather (changes in pressure of temperature, wind, etc.); and dynamics of the transportation modes or handling devices (acceleration, deceleration, and rotations of the transporter or handling device).
Ostrem, F. E.↗
Rotorcraft air transportation
Intermodal relationships and the particular ways in which they affect public transportation applications of rotorcraft are addressed. Some aspects of integrated services and general comparisons with other transportation modes are reviewed. Two potential application scenarios are discussed: down-to-downtown rotorcraft service and urban public transport rotorcraft service. It is concluded that to integrate well with ground access modes community rotorcraft service should be limited stop service with published schedules, and operate on a few specific routes between a few specific destinations. For downtown-to-downtown service, time savings favorable to rotorcraft are benefits that reflect its more direct access, relatively higher line-haul travel speeds, and less circuitous travel. For the scenario of public transport within urban areas, first, improving cruise speeds has a limited potential due to allowing for a ""station spacing'' effect. Secondly, public acceptance of higher acceleration/deceleration rates may be just as effective as a technological innovation as achieving higher cruise speeds.
Gilbert, G. A.↗
Refined Analysis of CO2 Emissions in Urban Air Mobility Networks
In this study, we examine the environmental impact of Urban Air Mobility (UAM) operations as measured via carbon dioxide (CO2) emissions by leveraging a computational model from previous studies that has been refined and expanded. Several scenarios are examined in which total transportation emissions for a representative day in a metro area are distributed differently among vehicle types and transportation modes. Specifically, we investigate the use of electric air vehicles in a UAM network; the increasing presence of electric ground vehicles for ground transportation; the impacts from implementing ridesharing in the UAM mode; and the effects of varying the electricity grid emissions. Results for a case study in the Chicago, IL metro area indicate that incorporating electric ground vehicles and UAM ridesharing can both lead to reduced CO2 emissions. These preliminary results indicate that carbon emissions from a UAM system leveraging ridesharing and all-electric aircraft may not be a practical operational limit on UAM, though further improvements to the modeling are warranted.
advanced air mobility↗
Refined Analysis of CO2 Emissions in Urban Air Mobility Networks
In this study, we examine the environmental impact of Urban Air Mobility (UAM) operations as measured via carbon dioxide (CO2) emissions by leveraging a computational model from previous studies that has been refined and expanded. Several scenarios are examined in which total transportation emissions for a representative day in a metro area are distributed differently among vehicle types and transportation modes. Specifically, we investigate the use of electric air vehicles in a UAM network; the increasing presence of electric ground vehicles for ground transportation; the impacts from implementing ridesharing in the UAM mode; and the effects of varying the electricity grid emissions. Results for a case study in the Chicago, IL metro area indicate that incorporating electric ground vehicles and UAM ridesharing can both lead to reduced CO2 emissions. These preliminary results indicate that carbon emissions from a UAM system leveraging ridesharing and all-electric aircraft may not be a practical operational limit on UAM, though further improvements to the modeling are warranted.
advanced air mobility↗
Solar atmospheric dynamics. II - Nonlinear models of the photospheric and chromospheric oscillations
The one-dimensional, nonlinear dynamics of the solar atmosphere is investigated, and models of the observed photospheric (300 s) and chromospheric (200 s) oscillations are described. These are resonances of acoustic wave cavities formed by the variation of the temperature and ionization between the subphotospheric, hydrogen convection zone and the chromosphere-corona transition region. The dependence of the oscillations upon the excitation and boundary conditions leads to the conclusion that for the observed amplitudes, the modes are independently excited and, as trapped modes, transport little if any mechanical flux. In the upper photosphere and lower chromosphere, where the two modes have comparable energy density, interference between them leads to apparent vertical phase delays which might be interpreted as evidence of an energy flux.
Leibacher, J.↗
Air Charter - The Business Airline of the Future...But, Does the Business Traveler Know?
Historically, FAR Part 121 commercial carriers have provided efficient, economical and safe air transportation for corporate and business users. Recently, however, corporate and business travelers find their travel plans disrupted by delays, bankruptcies, poor service, lost baggage, fare increases, labor strikes and other systemic difficulties that degrade their travel experience to unsatisfactory levels. This article examines these Part 121 service delivery problems and, utilizing a tripartite investigative methodology, examines an alternative air transport mode: FAR Part 135 on-demand charter travel products. This long extant segment of our national air transportation system is set prime to support increased demand for charter services. Corporate and business travelers are set prime to utilize viable, cost effective alternatives to commercial travel products. Two research questions emerge. First is whether corporate and business travelers are aware of Part 135 travel alternatives. Second is whether Part 135 charter service providers are aware of this latent demand and are effectively targeting this demand segment in their marketing efforts. The three-part surveys employed to investigate these questions examined demand side
Kaps, Robert W.↗
Feasibility Study of Cargo Airship Transportation Systems Powered by New Green Energy Technologies
The development of transportation systems that use new and sustainable energy technologies is of utmost importance due to the possible future shortfalls that current transportation modes will encounter because of increased volume and costs. The introduction and further research and development of new transportation and energy systems by materials researchers at the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) and the Department of Transportation are discussed in this Technical Memorandum. In this preliminary study, airship concepts were assessed for cargo transportation using various green energy technologies capable of 24-hour operation (i.e., night and day). Two prototype airships were successfully constructed and tested at LaRC to demonstrate their feasibility: one with commercially available solar cells for operation during the daytime and one with microwave rectennas (i.e., rectifying antennas) developed in-house for night-time operation. The test results indicate the feasibility of a cargo transportation airship powered by new green energy sources and wireless power technology. Future applications will exploit new green energy sources that use materials and devices recently developed or are in the process of being developed at LaRC. These include quantum well SiGe solar cells; low, mid-, and high temperature thermoelectric modules; and wireless microwave and optical rectenna devices. This study examines the need and development of new energy sources for transportation, including the current status of research, materials, and potential applications.
Skuza, Jonathan R.↗
Overcoming two significant hurdles to space power generation Transportation and assembly
The design of large, space-based power generation satellites is strongly influenced by the transportation modes available and the assembly methods adopted. Flight plans for assembly are explored using the Space Shuttle as the transport vehicle. Future heavy-lift launch systems are postulated, and their impact on assembly cost of operational Solar Satellite Power Stations (SSPS) presented. Sensitivity to various levels of ground detail parts prefabrication are compared to corresponding levels of orbital fabrication. Assumptions concerning the degree of human skills are outlined, and related to the method of assembly. Cost comparisons and recommendations for continued studies are developed.
Kline, R.↗
(abstract) Alkali Metal Diffusion Through Porous Metal Electrodes in AMTEC Cells
The mechanisms of mass transport of an alkali metal through porous metal electrodes in alkali metal thermal-to-electric converter AMTEC cells is important in optimizing these high current density devices, but also affords the opportunity to investigate a variety of simple mass transport modes at high temperatures via electrochemical techniques. We have previously reported evidence of ionic, free molecular flow, and surface transport of sodium in several types of AMTEC electrodes. Quantitative investigations of Na transport through WPt(sub 3.5) via surface or grain boundary diffusion, and K transport through porous Mo electrodes by free molecular flow, over large ranges of temperature have been performed. WPt(sub 3.5) has especially low transport impedance over the 950 to 1200K temperature range. New results are the Na through porous WPt(sub 3.5) and K through porous Mo diffusion rates and mechanisms.
alkali metal mass transport porous metal electrode↗
A Solar Model with g-Modes
Good evidence is assembled showing that the Suit's core arid surface vary on time scales from a month to a decade arid that a number of scales are similar. The most plausible source for numerous long time scales and periodicities is long-lived global oscillations. This suggests g-modes (oscillations restored mainly by buoyancy) because they particularly affect the core and base of the convective envelope, which then indirectly modulates the surface. Also, standing g-modes have rotational properties that match many observed periodicities. But the standard solar model (SSM) has a static core and excites few if any g-modes. making new interior structures worth exploring. The model outlined here assumes two well mixed shells near 0.18 and 0.68 R, (13 = solar radius) where sound speed data shows sharp deviations from the SSM. Mixing is sustained by flows driven by the oscillations. The shells form a cavity that excludes g-modes from their main damping region below 0.1 R, assisting their net excitation and increasing their oscillation periods by at least a factor of two and probably much more. In terms of the solar luminosity L, the modes transport up through the cavity a power approx. 0.004 L as a lower limit and 0.11 L as all upper limit. The modes dissipate energy in the outer shell and cool the inner shell, asymmetrically in each case, and this stimulates occasional convective events whose response time is typically 0.8 years longer near the inner shell. Such events cool the core and reduce neutrino flux while heating the envelope and increasing solar activity. This gives a physical basis for a well mixed Sun with low neutrino flux and basis for the observed anticorrelation and lag of neutrino behind surface activity.
Wolff, Charles L.↗
Compliant wall-turbulent skin-friction reduction research
Previous compliant-wall experiments successful in reducing skin-friction drag probably have had a (unplanned) membrane resonance at a favorable frequency, amplitude, wave shape, length, and speed. The most probable drag reduction mechanism involves a direct coupling between the fluid and the moving wall when the wall natural resonance frequencies are near the fundamental turbulent burst frequency. Local skin-friction reductions of 61% were measured with mylar/PVC plastisol compliant surfaces. These reductions were observed only at certain flow conditions, indicating that changing tunnel total temperature may have altered the substrate dynamic modulus, damping, and coupled mylar tension. Apparently, the coupled membrane/substrate must be excited in compatible narrow-band natural frequency modes. An accelerated effort is required to develop practical durable compliant surfaces optimized for maximum drag reduction. Application of compliant walls to other transportation modes appears feasible with liquid flows offering the greatest skin-friction drag reduction potential.
Fischer, M. C.↗
Challenges of short-haul air transportation
Short-haul transportation systems are characterized by low average utilization, high peak but low average passenger demand, severe competition from other transportation modes, high fixed costs and high operating costs. Studies were conducted to analyze the operational requirements and market size for medium-density air transportation. The determination of the aircraft that will most efficiently meet the requirements of this market requires the careful evaluation of variable parameters such as engine cycles, payload, field length range and type of high-lift system. Low noise, low cost and thrust reversing capability are the basic criteria for the propulsion system. It is concluded that aircraft of less than 50-seat capacity cannot generate satisfactory profits operating in the medium-density market.
Galloway, T. L.↗
Convective-diffusive transport in vapor growth ampoules
Theoretical and experimental work on heat and mass transport in crystal growth by closed ampoule vapor transport is reviewed. It is shown that double-diffusive phenomena, together with the three-dimensional boundary conditions of real systems lead to a complexity of the transport modes that are beyond the reach of the simplifying models currently used in the materials preparation literature. Consequences of the new insights for earth-bound vapor transport and for optimization of future space experiments are discussed.
Rosenberger, F.↗
Analysis of Small Aircraft as a Transportation System
An analysis was conducted to examine the market viability of small aircraft as a transportation mode in competition with automobile and scheduled commercial air travel by estimating the pool of users that would potentially switch to on-demand air travel due to cost/time savings. The basis for the analysis model was the Integrated Air Transportation System Evaluation Tool (IATSET) which was developed under contract to NASA by the Logistics Management Institute. IATSET is a macroeconomic model that predicts at a National level the mode choice between automobile, scheduled air, and on-demand air travel based on the value of a travelers time and monetary cost of the trip. A number of modifications are detailed to the original IATSET to better model the changing small aircraft environment. The potential trip market was modeled for the Eclipse 500 operated as a corporate jet and as an air taxi for the business travel market. The Cirrus 20R and a $80K single engine piston aircraft (based on automobile manufacturing technology) are evaluated in the pleasure and personal business travel market.
Dollyhigh, Samuel M.↗
Study of Fluid Flow Control In Protein Crystallization Using Strong Magnetic Fields
An important component in biotechnology, particularly in the area of protein engineering and rational drug design is the knowledge of the precise three-dimensional molecular structure of proteins. The quality of structural information obtained from X-ray diffraction methods is directly dependent on the degree of perfection of the protein crystals. As a consequence, the growth of high quality macromolecular crystals for diffraction analyses has been the central focus for biochemists, biologists, and bioengineers. Macromolecular crystals are obtained from solutions that contain the crystallizing species in equilibrium with higher aggregates, ions, precipitants, other possible phases of the protein, foreign particles, the walls of the container, and a likely host of other impurities. By changing transport modes in general, i.e., reduction of convection and sedimentation, as is achieved in 'microgravity', researchers have been able to dramatically affect the movement and distribution of macromolecules in the fluid, and thus their transport, formation of crystal nuclei, and adsorption to the crystal surface. While a limited number of high quality crystals from space flights have been obtained, as the recent National Research Council (NRC) review of the NASA microgravity crystallization program pointed out, the scientific approach and research in crystallization of proteins has been mainly empirical yielding inconclusive results. We postulate that we can reduce convection in ground-based experiments and we can understand the different aspects of convection control through the use of strong magnetic fields and field gradients. Whether this limited convection in a magnetic field will provide the environment for the growth of high quality crystals is still a matter of conjecture that our research will address. The approach exploits the variation of fluid magnetic susceptibility with concentration for this purpose and the convective damping is realized by appropriately positioning the crystal growth cell so that the magnetic susceptibility force counteracts terrestrial gravity. The general objective is to test the hypothesis of convective control using a strong magnetic field and magnetic field gradient and to understand the nature of the various forces that come into play. Specifically we aim to delineate causative factors and to quantify them through experiments, analysis and numerical modeling. Once the basic understanding is obtained, the study will focus on testing the hypothesis on proteins of pyruvate dehydrogenase complex (PDC), proteins E1 and E3. Obtaining high crystal quality of these proteins is of great importance to structural biologists since their structures need to be determined.
Ramachandran, N.↗