Search NASA⌕ Search

SEARCH · Search NASA

Results for “Governance”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14

Analysis of the financial factors governing the profitability of lunar helium-3

Financial factors influencing the profitability of the mining and utilization of lunar helium-3 are examined. The analysis addressed the following questions: (1) which financial factors have the greatest leverage on the profitability of He-3; (2) over what range can these factors be varied to keep the He-3 option profitable; and (3) what ultimate effect could this energy source have on the price of electricity for U.S. consumers. Two complementary methods of analysis were used in the assessment: rate of return on incremental investment required and reduction revenue requirements (total cost to customers) achieved. Some of the factors addressed include energy demand, power generation costs with and without fusion, profitability for D-He(3) fusion, annual capital and operating costs, launch mass and costs, He-3 price, and government funding. Specific conclusions are made with respect to each of the companies considered: utilities, lunar mining company, and integrated energy company.

Kulcinski, G. L.↗

Factors governing the total rainfall yield from continental convective clouds

Several important factors that govern the total rainfall from continental convective clouds were investigated by tracking thousands of convective cells in Israel and South Africa. The rainfall volume yield (Rvol) of the individual cells that build convective rain systems has been shown to depend mainly on the cloud-top height. There is, however, considerable variability in this relationship. The following factors that influence the Rvol were parameterized and quantitatively analyzed: (1) cloud base temperature, (2)atmospheric instability, and (3) the extent of isolation of the cell. It is also shown that a strong low level forcing increases the duration of Rvol of clouds reaching the same vertical extent.

Rosenfeld, Daniel↗

Physical considerations governing computation of turbulent flows over bodies at large incidence

The physical aspects governing accurate numerical simulation of turbulent flows having large regions of crossflow separation are re-examined. Time-accurate, three-dimensional fine-grid Navier-Stokes solutions were obtained for turbulent subsonic and supersonic flows over a slender ogive-cylinder body of revolution at large angles of attack. These flowfields are complex and contain regions of crossflow separation and an organized leeward-side vortex structure. An algebraic eddy-viscosity turbulence model has been modified to correctly account for the effects of the vortices on the underlying viscous layers. The numerical results show that the vortical flow structure of both subsonic and supersonic high incidence flows are similar, and can be accurately treated by the turbulence model. As the angle of attack is increased, the effectiveness of the model increases since the influence of the vortices on the underlying boundary layer decreases.

Degani, David↗

The NASA/industry Design Analysis Methods for Vibrations (DAMVIBS) Program: A government overview

LaRC, under the Design Analysis Methods for Vibrations (DAMVIBS) Program, set out in 1984 to establish the technology base needed by the rotorcraft industry for developing an advanced finite-element-based dynamics design analysis capability for vibrations. Considerable work was performed by the industry participants in the program since that time. Because the DAMVIBS Program is being phased out, a government/industry assessment of the program was made to identify those accomplishments and contributions which may be ascribed to the program. The purpose is to provide an overview of the program and its accomplishments and contributions from the perspective of the government sponsoring organization.

Kvaternik, Raymond G.↗

On the spatial evolution of long-wavelength Goertler vortices governed by a viscous-inviscid interaction

The generation of long-wavelength, viscous-inviscid interactive Goertler vortices is studied in the linear regime by numerically solving the time-dependent governing equations. It is found that time-dependent surface deformations, which assume a fixed nonzero shape at large times, generate steady Goertler vortices that amplify in the downstream direction. Thus, the Goertler instability in this regime is shown to be convective in nature, contrary to the earlier findings of Ruban and Savenkov. The disturbance pattern created by steady and streamwise-elongated surface obstacles on a concave surface is examined in detail, and also contrasted with the flow pattern due to roughness elements with aspect ratio of order unity on flat surfaces. Finally, the applicability of the Briggs-Bers criterion to unstable physical systems of this type is questioned by providing a counterexample in the form of the inviscid limit of interactive Goertler vortices.

Choudhari, Meelan↗

CFD lends the government a hand

The present survey of important and novel CFD applications being developed and implemented by U.S. Government contractors gives attention to naval vessel flow-modeling, Army ballistic and rotary wing aerodynamics, and NASA hypersonic vehicle related applications of CFD. CFD-generated knowledge of numerical algorithms, fluid motion, and supercomputer use is being incorporated into such additional areas as computational electromagnetics and acoustics. Attention is presently given to CFD methods' development status in such fields as submarine boundary layers, hypersonic kinetic energy projectile shock structures, helicopter main rotor tip flows, and National Aerospace Plane aerothermodynamics.

Lekoudis, Spiro↗

The NASA/Industry Design Analysis Methods for Vibrations (DAMVIBS) Program - A government overview

An overview is presented of government contributions to the program called Design Analysis Methods for Vibrations (DAMV) which attempted to develop finite-element-based analyses of rotorcraft vibrations. NASA initiated the program with a finite-element modeling program for the CH-47D tandem-rotor helicopter. The DAMV program emphasized four areas including: airframe finite-element modeling, difficult components studies, coupled rotor-airframe vibrations, and airframe structural optimization. Key accomplishments of the program include industrywide standards for modeling metal and composite airframes, improved industrial designs for vibrations, and the identification of critical structural contributors to airframe vibratory responses. The program also demonstrated the value of incorporating secondary modeling details to improving correlation, and the findings provide the basis for an improved finite-element-based dynamics design-analysis capability.

Kvaternik, Raymond G.↗

The NASA/industry Design Analysis Methods for Vibrations (DAMVIBS) program: A government overview

NASA-Langley, under the Design Analysis Methods for Vibrations (DAMVIBS) Program, set out in 1984 to establish the technology base needed by the rotorcraft industry for developing an advanced finite-element-based dynamics design analysis capability for vibrations. Considerable work has been done by the industry participants in the program since that time. Because the DAMVIBS Program is being phased out, a government/industry assessment of the program has been made to identify those accomplishments and contributions which may be ascribed to the program. The purpose of this paper is to provide an overview of the program and its accomplishments and contributions from the perspective of the government sponsoring organization.

Kvaternik, Raymond G.↗

A research experiment on facilitation and formation of joint research and development programs between government, industry, and universities: Overview, preliminary findings, and observations

Presented is an overview of an experiment to explore the free-market approach to public-private collaboration through the development and implementation of a joint venture mechanism to enable formation of R&D projects between government, industry and academia. Some preliminary results related to time-to-commercialization and economic competitiveness are discussed.

Shariq, Syed Z.↗

Traditional and nontraditional internships in government

Traditional and nontraditional methods for training technical writers-editors within the federal government are discussed. It is concluded that cooperative education that combines work experience with classroom instruction provides an excellent method for locating and training competent and reliable young professionals.

Stohrer, Freda F.↗

Shape optimization governed by the Euler equations using an adjoint method

A numerical approach for the treatment of optimal shape problems governed by the Euler equations is discussed. Focus is on flows with embedded shocks. A very simple problem is considered: the design of a quasi-one-dimensional Laval nozzle. A cost function and a set of Lagrange multipliers are introduced to achieve the minimum. The nature of the resulting costate equations is discussed. A theoretical difficulty that arises for cases with embedded shocks is pointed out and solved. Finally, some results are given to illustrate the effectiveness of the method.

Iollo, Angelo↗

Government Information Locator Service (GILS). Draft report to the Information Infrastructure Task Force

This is a draft report on the Government Information Locator Service (GILS) to the National Information Infrastructure (NII) task force. GILS is designed to take advantage of internetworking technology known as client-server architecture which allows information to be distributed among multiple independent information servers. Two appendices are provided -- (1) A glossary of related terminology and (2) extracts from a draft GILS profile for the use of the American National Standard Information Retrieval Application Service Definition and Protocol Specification for Library Applications.

Source record↗

SPARTNIK: Engineering catalyst for government and industry

Industrial demands for highly motivated and competent technical personnel to carry forward with the technological goals of the US has posed a significant challenge to graduating engineers. While curricula has improved and diversified over time to meet these industry demands, relevant industry experience is not always available to undergraduates. The microsatellite development program at San Jose State University (SJSU) has allowed an entire undergraduate senior class to utilize a broad range of training and education to refine their engineering skills, bringing them closer to becoming engineering professionals. Close interaction with industry mentors and manufacturers on a real world project provides a significant advantage to educators and students alike. With support from companies and government agencies, the students have designed and manufactured a microsatellite, designed to be launched into a low Earth orbit. This satellite will gather telemetry for characterizing the state of the spacecraft. This will enable the students to have a physical check on their predicted value of spacecraft subsystem performance. Additional experiments will also be undertaken during the two year lifetime, including micro-meteorite impact sensing and capturing digital color images of the Earth. This paper will detail the process whereby students designed, prototype and manufactured a small satellite in a large team environment, along with the experiments that will be performed on board. With the project's limited funds, it needed the support of many industry companies to help with technical issues and hardware acquisition. Among the many supporting companies, NASA's space shuttle small payloads program could be used for an affordable launch vehicle for the student project. The paper address these collaborations between the student project and industry support, as well as explaining the benefits to both. The paper draws conclusion on how these types of student projects can be used by industry as a feasible resource for developing small platforms for space based experiments, as well as increasing the practical experience and engineering knowledge of graduating students. These benefits to industry and universities, can lead to a close working relationship between the two. These types of projects can facilitate the development of low-cost space rated parts to be used by the industry and university projects. It can also help with the understanding and use of acceptable risk non-space rated parts reducing the cost of the spacecraft. This will lead to the development of low cost platforms for space based experiments, providing research companies an inexpensive, long duration platform to conduct their in-space experiments, while better preparing engineering undergraduates for their transition into the work force.

Prass, James D.↗

The cornerstone of data warehousing for government applications

The purpose of this paper is to discuss data warehousing storage issues and the impact of EMC open storage technology for meeting the myriad of challenges government organizations face when building Decision Support/Data Warehouse system.

Kenbeek, Doug↗

A Nonlinear Programming Perspective on Sensitivity Calculations for Systems Governed by State Equations

This paper discusses the calculation of sensitivities. or derivatives, for optimization problems involving systems governed by differential equations and other state relations. The subject is examined from the point of view of nonlinear programming, beginning with the analytical structure of the first and second derivatives associated with such problems and the relation of these derivatives to implicit differentiation and equality constrained optimization. We also outline an error analysis of the analytical formulae and compare the results with similar results for finite-difference estimates of derivatives. We then attend to an investigation of the nature of the adjoint method and the adjoint equations and their relation to directions of steepest descent. We illustrate the points discussed with an optimization problem in which the variables are the coefficients in a differential operator.

Lewis, Robert Michael↗

Basic Governing Equations for the Flight Regimes of Aeroassisted Orbital Transfer Vehicles

The basic governing equations for the low-density, high-enthalpy flow regimes expected in the shock layers over the heat shields of the proposed aeroassisted orbital transfer vehicles are derived by combining and extending existing theories. The conservation equations are derived from gas kinetic principles for a four-component ionized gas consisting of neutral molecules, neutral atoms, singly ionized ions, and electrons, assuming a continuum flow. The differences among translational-rotational, vibrational, and electron temperatures are accounted for, as well as chemical nonequilibrium and electric-charge separation. Expressions for convective and viscous fluxes, transport properties, and the terms representing interactions among various energy modes are explicitly given. The expressions for the rate of electron-vibration energy transfer, which violates the Landau-Teller conditions, are derived by solving the system of master equations accounting for the multiple-level transitions.

Lee, Jong-Hun↗