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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 523 records · Page 29

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NASA NTRS1984

Three-dimensional viscous design methodology for advanced technology aircraft supersonic inlet systems

A broad program to develop advanced, reliable, and user oriented three-dimensional viscous design techniques for supersonic inlet systems, and encourage their transfer into the general user community is discussed. Features of the program include: (1) develop effective methods of computing three-dimensional flows within a zonal modeling methodology; (2) ensure reasonable agreement between said analysis and selective sets of benchmark validation data; (3) develop user orientation into said analysis; and (4) explore and develop advanced numerical methodology. Previously announced in STAR as N84-13190

Anderson, B. H.↗

NASA NTRS1984

Sensitivity analysis of limit state functions for probability-based plastic design

The evaluation of the total probability of a plastic collapse failure P sub f for a highly redundant structure of random interdependent plastic moments acted on by random interdepedent loads is a difficult and computationally very costly process. The evaluation of reasonable bounds to this probability requires the use of second moment algebra which involves man statistical parameters. A computer program which selects the best strategy for minimizing the interval between upper and lower bounds of P sub f is now in its final stage of development. The relative importance of various uncertainties involved in the computational process on the resulting bounds of P sub f, sensitivity is analyzed. Response sensitivities for both mode and system reliability of an ideal plastic portal frame are shown.

Frangopol, D. M.↗

NASA NTRS1985

Stress analyses of B-52 pylon hooks

The NASTRAN finite element computer program was used in the two dimensional stress analysis of B-52 carrier aircraft pylon hooks: (1) old rear hook (which failed), (2) new rear hook (improved geometry), (3) new DAST rear hook (derated geometry), and (4) front hook. NASTRAN model meshes were generated by the aid of PATRAN-G computer program. Brittle limit loads for all the four hooks were established. The critical stress level calculated from NASTRAN agrees reasonably well with the values predicted from the fracture mechanics for the failed old rear hook.

Ko, W. L.↗

NASA NTRS1985

A hybrid numerical technique for predicting the aerodynamic and acoustic fields of advanced turboprops

A hybrid numerical procedure is presented for the prediction of the aerodynamic and acoustic performance of advanced turboprops. A hybrid scheme is proposed which in principle leads to a consistent simultaneous prediction of both fields. In the inner flow a finite difference method, the Approximate-Factorization Alternating-Direction-Implicit (ADI) scheme, is used to solve the nonlinear Euler equations. In the outer flow the linearized acoustic equations are solved via a Boundary-Integral Equation (BIE) method. The two solutions are iteratively matched across a fictitious interface in the flow so as to maintain continuity. At convergence the resulting aerodynamic load prediction will automatically satisfy the appropriate free-field boundary conditions at the edge of the finite difference grid, while the acoustic predictions will reflect the back-reaction of the radiated field on the magnitude of the loading source terms, as well as refractive effects in the inner flow. The equations and logic needed to match the two solutions are developed and the computer program implementing the procedure is described. Unfortunately, no converged solutions were obtained, due to unexpectedly large running times. The reasons for this are discussed and several means to alleviate the situation are suggested.

Homicz, G. F.↗

NASA NTRS1994

Automated Scalability Analysis Tools for Message Passing Parallel Programs

In order to develop scalable parallel applications, a number of programming decisions have to be made during the development of the program. Performance tools that help in making these decisions are few, if existent. Traditionally, performance tools have focused on exposing performance bottlenecks of small-scale executions of the program. However, it is common knowledge that programs that perform exceptionally well on small processor configurations, more often than not, perform poorly when executed on larger processor configurations. Hence, new tools that predict the execution characteristics of scaled-up programs are an essential part of an application developers toolkit. In this paper we discuss important issues that need to be considered in order to build useful scalability analysis tools for parallel programs. We introduce a simple tool that automatically extracts scalability characteristics of a class of deterministic parallel programs. We show with the help of a number of results on the Intel iPSC/860, that predictions are within reasonable bounds.

Sarukkai, Sekhar R.↗

DOE OSTI2012

Data Preservation in High Energy Physics

Data from high-energy physics (HEP) experiments are collected with significant financial and human effort and are mostly unique. At the same time, HEP has no coherent strategy for data preservation and re-use. An inter-experimental Study Group on HEP data preservation and long-term analysis was convened at the end of 2008 and held two workshops, at DESY (January 2009) and SLAC (May 2009). This document is an intermediate report to the International Committee for Future Accelerators (ICFA) of the reflections of this Study Group. Large data sets accumulated during many years of detector operation at particle accelerators are the heritage of experimental HEP. These data sets offer unique opportunities for future scientific studies, sometimes long after the shut-down of the actual experiments: new theoretical input; new experimental results and analysis techniques; the quest for high-sensitivity combined analyses; the necessity of cross checks. In many cases, HEP data sets are unique; they cannot and most likely will not be superseded by data from newer generations of experiments. Once lost, or in an unusable state, HEP data samples cannot be reasonably recovered. The cost of conserving this heritage through a collaborative, target-oriented long-term data preservation program would be small, compared to the costs of past experimental projects or to the efforts to re-do experiments. However, this cost is not negligible, especially for collaborations close or past their end-date. The preservation of HEP data would provide today's collaborations with a secure way to complete their data analysis and enable them to seize new scientific opportunities in the coming years. The HEP community will benefit from preserved data samples through reanalysis, combination, education and outreach. Funding agencies would receive more scientific return, and a positive image, from their initial investment leading to the production and the first analysis of preserved data.

43 PARTICLE ACCELERATORS↗

DOE OSTI2016

Stripline kicker for integrable optics test accelerator

We present a design of a stripline kicker for Integrable Optics Test Accelerator (IOTA). For its experimental program IOTA needs two full-aperture kickers, capable to create an arbitrary controllable kick in 2D. For that reason their strengths are variable in a wide range of amplitudes up to 16 mrad, and the pulse length 100 ns is less than a revolution period for electrons. In addition, the kicker should have a physical aperture of 40 mm for a proposed operation with proton beam, and an outer size of 70 mm to fit inside existing quadrupole magnets to save space in the ring. Computer simulations using CST Microwave Studio show high field uniformity and wave impedance close to 50 {\Omega}.

43 PARTICLE ACCELERATORS↗

DOE OSTI2016

U.S. Senate Bill S.854-IS - A Maladjusted Politicized Maze for Consent-Based Siting of New HLW-Repositories - 16019

At the end of 2015, the USA's HLW-disposal program had been on hold since 2010 pending the enactment of enabling legislation for one or both of: 1) The Yucca Mountain HLW repository; and/or 2) The law proposed in Senate Bill S.854-IS 'to establish a new organization to manage nuclear waste, provide a consensual process for siting nuclear waste facilities, ensure adequate funding for managing nuclear waste, and for other purposes'. But, S.854-IS does not acknowledge the existence of the Yucca Mountain HLW repository, which, if re-enabled, would affect both when another HLW repository would be needed and its disposal capacity. Furthermore, it neither timely nor meaningfully integrates waste generators, facility-host(s) and other directly affected parties with the new 'implementing' organizations deemed to be more susceptible to political influence and interferences than those plaguing the Yucca Mountain HLW repository program since 1987 that resulted in a multitude of contentions, lawsuits, delays, and increased costs. For these and other reasons very compelling and conclusive to the author, the legal status of the YM HLW repository should be 'definitive' before a law based upon S.854-IS is enacted. Instead, the near-term focus should be on: 1. Defining 'consent-based' quantitatively. 2. Promptly siting and opening at least one large, expandable, 'consolidated' HLW-storage facility allowing the government to begin taking title to commercially-generated HLW; most-expeditiously accomplished by amending existing legislation. 3. Updating S.854-IS based on lessons learned about siting, developing, and licensing nuclear-waste-storage and -disposal facilities in the USA and abroad the past 30+ years. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

NASA NTRS2003

Superalloy Disk With Dual-Grain Structure Spin Tested

Advanced nickel-base disk alloys for future gas turbine engines will require greater temperature capability than current alloys, but they must also continue to deliver safe, reliable operation. An advanced, nickel-base disk alloy, designated Alloy 10, was selected for evaluation in NASA s Ultra Safe Propulsion Project. Early studies on small test specimens showed that heat treatments that produced a fine grain microstructure promoted high strength and long fatigue life in the bore of a disk, whereas heat treatments that produced a coarse grain microstructure promoted optimal creep and crack growth resistance in the rim of a disk. On the basis of these results, the optimal combination of performance and safety might be achieved by utilizing a heat-treatment technology that could produce a fine grain bore and coarse grain rim in a nickel-base disk. Alloy 10 disks that were given a dual microstructure heat treatment (DMHT) were obtained from NASA s Ultra-Efficient Engine Technology (UEET) Program for preliminary evaluation. Data on small test specimens machined from a DMHT disk were encouraging. However, the benefit of the dual grain structure on the performance and reliability of the entire disk still needed to be demonstrated. For this reason, a high temperature spin test of a DMHT disk was run at 20 000 rpm and 1500 F at the Balancing Company of Dayton, Ohio, under the direction of NASA Glenn Research Center personnel. The results of that test showed that the DMHT disk exhibited significantly lower crack growth than a disk with a fine grain microstructure. In addition, the results of these tests could be accurately predicted using a two-dimensional, axisymmetric finite element analysis of the DMHT disk. Although the first spin test demonstrated a significant performance advantage associated with the DMHT technology, a second spin test on the DMHT disk was run to determine burst margin. The disk burst in the web at a very high speed, over 39 000 rpm, in line with the predicted location and speed. Furthermore, significant growth of the disk was observed before failure, in line with predictions, clearly demonstrating the reliability and safety of the DMHT technology. Although successful spin testing in Ultra Safe's Nickel Disk Program represents a significant milestone for DMHT technology, realistic engine operation will require repeated loading of a DMHT nickel disk. For this reason, a cyclic spin test study of DMHT nickel disk technology has been proposed to start in fiscal year 2003 under NASA's Aviation Safety Program. The goal of this program will be to determine the fatigue failure mechanism in DMHT nickel disks, thereby demonstrating the reliability and safety of DMHT technology under repetitive loading conditions encountered in realistic engine operation.

Gayda, John↗

NASA NTRS1995

Software packager user's guide

Software integration is a growing area of concern for many programmers and software managers because the need to build new programs quickly from existing components is greater than ever. This includes building versions of software products for multiple hardware platforms and operating systems, building programs from components written in different languages, and building systems from components that must execute on different machines in a distributed network. The goal of software integration is to make building new programs from existing components more seamless -- programmers should pay minimal attention to the underlying configuration issues involved. Libraries of reusable components and classes are important tools but only partial solutions to software development problems. Even though software components may have compatible interfaces, there may be other reasons, such as differences between execution environments, why they cannot be integrated. Often, components must be adapted or reimplemented to fit into another application because of implementation differences -- they are implemented in different programming languages, dependent on different operating system resources, or must execute on different physical machines. The software packager is a tool that allows programmers to deal with interfaces between software components and ignore complex integration details. The packager takes modular descriptions of the structure of a software system written in the package specification language and produces an integration program in the form of a makefile. If complex integration tools are needed to integrate a set of components, such as remote procedure call stubs, their use is implied by the packager automatically and stub generation tools are invoked in the corresponding makefile. The programmer deals only with the components themselves and not the details of how to build the system on any given platform.

Callahan, John R.↗

NASA NTRS1978

Easy Meal

The woman pictured below is sitting down to a nutritious, easily-prepared meal similar to those consumed by Apollo astronauts. The appetizing dishes shown were created simply by adding water to the contents of a Mountain House* Easy Meal package of freeze dried food. The Easy Meal line is produced by Oregon Freeze Dry Foods, Inc., Albany, Oreaon, a pioneer in freeze drying technology and a company long associated with NASA in developing suitable preparations for use on manned spacecraft. Designed to provide nutritionally balanced, attractive hot meals for senior adults, Easy Meal is an offshoot of a 1975-77 demonstration project managed by Johnson Space Center and called Meal System for the Elderly. The project sought ways to help the estimated 3.5 million elderly Americans who are unable to take advantage of existing meal programs. Such services are provided by federal, state and local agencies, but they are not available to many who live in rural areas, or others who are handicapped, temporarily ill or homebound for other reasons. Oregon Freeze Dry Foods was a participant in that multi-agency cooperative project. With its Easy Meal assortment of convenience foods pictured above left, the company is making commercially available meal packages similar to those distributed in the Meal System for the Elderly program. In the freeze drying process, water is extracted from freshly-cooked foods by dehydration at very low temperatures, as low as 50 I degrees below zero. Flavor is locked in by packaging the dried food in pouches which block out moisture and oxygen, the principal causes of food deterioration; thus the food can be stored for long periods without refrigeration. Meals are reconstituted by adding hot or cold water, depending on the type of food, and they are table ready in five to 10 minutes. Oregon Freeze Dry Foods offers five different meal packages and plans to expand the line.

Source record↗

NASA NTRS1995

Intelligent automated surface grid generation

The goal of our research is to produce a flexible, general grid generator for automated use by other programs, such as numerical optimizers. The current trend in the gridding field is toward interactive gridding. Interactive gridding more readily taps into the spatial reasoning abilities of the human user through the use of a graphical interface with a mouse. However, a sometimes fruitful approach to generating new designs is to apply an optimizer with shape modification operators to improve an initial design. In order for this approach to be useful, the optimizer must be able to automatically grid and evaluate the candidate designs. This paper describes and intelligent gridder that is capable of analyzing the topology of the spatial domain and predicting approximate physical behaviors based on the geometry of the spatial domain to automatically generate grids for computational fluid dynamics simulators. Typically gridding programs are given a partitioning of the spatial domain to assist the gridder. Our gridder is capable of performing this partitioning. This enables the gridder to automatically grid spatial domains of wide range of configurations.

Yao, Ke-Thia↗

DOE OSTI2012

Mentoring Human Performance - 12480

Although the positive effects of implementing a human performance approach to operations can be hard to quantify, many organizations and industry areas are finding tangible benefits to such a program. Recently, a unique mentoring program was established and implemented focusing on improving the performance of managers, supervisors, and work crews, using the principles of Human Performance Improvement (HPI). The goal of this mentoring was to affect behaviors and habits that reliably implement the principles of HPI to ensure continuous improvement in implementation of an Integrated Safety Management System (ISMS) within a Conduct of Operations framework. Mentors engaged with personnel in a one-on-one, or one-on-many dialogue, which focused on what behaviors were observed, what factors underlie the behaviors, and what changes in behavior could prevent errors or events, and improve performance. A senior management sponsor was essential to gain broad management support. A clear charter and management plan describing the goals, objectives, methodology, and expected outcomes was established. Mentors were carefully selected with senior management endorsement. Mentors were assigned to projects and work teams based on the following three criteria: 1) knowledge of the work scope; 2) experience in similar project areas; and 3) perceived level of trust they would have with project management, supervision, and work teams. This program was restructured significantly when the American Reinvestment and Recovery Act (ARRA) and the associated funding came to an end. The program was restructured based on an understanding of the observations, attributed successes and identified shortfalls, and the consolidation of those lessons. Mentoring the application of proven methods for improving human performance was shown effective at increasing success in day-to-day activities and increasing confidence and level of skill of supervisors. While mentoring program effectiveness is difficult to measure, and return on investment is difficult to quantify, especially in complex and large organizations where the ability to directly correlate causal factors can be challenging, the evidence presented by Sydney Dekker, James Reason, and others who study the field of human factors does assert managing and reducing error is possible. Employment of key behaviors-HPI techniques and skills-can be shown to have a significant impact on error rates. Our mentoring program demonstrated reduced error rates and corresponding improvements in safety and production. Improved behaviors are the result, of providing a culture with consistent, clear expectations from leadership, and processes and methods applied consistently to error prevention. Mentoring, as envisioned and executed in this program, was effective in helping shift organizational culture and effectively improving safety and production. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

NASA NTRS2015

X-Ray Optics at NASA Marshall Space Flight Center

NASA's Marshall Space Flight Center (MSFC) engages in research, development, design, fabrication, coating, assembly, and testing of grazing-incidence optics (primarily) for x-ray telescope systems. Over the past two decades, MSFC has refined processes for electroformed-nickel replication of grazing-incidence optics, in order to produce high-strength, thin-walled, full-cylinder x-ray mirrors. In recent years, MSFC has used this technology to fabricate numerous x-ray mirror assemblies for several flight (balloon, rocket, and satellite) programs. Additionally, MSFC has demonstrated the suitability of this technology for ground-based laboratory applications-namely, x-ray microscopes and cold-neutron microscopes and concentrators. This mature technology enables the production, at moderately low cost, of reasonably lightweight x-ray telescopes with good (15-30 arcsecond) angular resolution. However, achieving arcsecond imaging for a lightweight x-ray telescope likely requires development of other technologies. Accordingly, MSFC is conducting a multi-faceted research program toward enabling cost-effective production of lightweight high-resolution x-ray mirror assemblies. Relevant research topics currently under investigation include differential deposition for post-fabrication figure correction, in-situ monitoring and control of coating stress, and direct fabrication of thin-walled full-cylinder grazing-incidence mirrors.

X-ray Optics↗

NASA NTRS2015

X-Ray Optics at NASA Marshall Space Flight Center

X-ray telescope↗

DOE OSTI2012

The Design of the Parallel Box Cavity with New Radial RF Coupler Design

The design of a E/H parallel cavity has been described. It has been designed with the RF simulation program HFSS. HFSS has been very successfully been used to design and fabricate the Orthogonal E/H box cavity. The main reason for this design choice is to move the RF coupling aperture to surface of minimum electric field gradient. It is suspected that this change will remove the damaged observed in the coupling area experimentally observed in the LBL Pillbox cavity. Another reason for this change is that it corresponds to the location of the coupling aperture in a future real experimental cooling channel. Also, with this design the coupling factor to the cavity can be made adjustable externally, a very useful feature.

43 PARTICLE ACCELERATORS↗

DOE OSTI2018

Quarterly Management Document – FY18, 1st Quarter, Physics-based Creep Simulations of Thick Section Welds in High Temperature and Pressure Applications

During the 1st quarter of FY18 modeling and simulation of the creep of thick section welds continued although some workscope from FY17 still needs to be completed. Four stress drop tests to determine the threshold stress for creep in Alloy 740H were carried out. One has finished and post-test analysis shows a threshold creep stress of about 67 MPa which is lower than that found in a previous program for Alloy 617 at the same temperature. Alloy 617 is not as creep resistant as Alloy 740H and the reason for the lower than expected threshold stress for Alloy 740H is being investigated further. Also analysis of the gamma prime particle size in an aging study closely follows the aging characteristics of gamma prime in Alloy 617. Further analysis of other aged materials will be carried out during the 2nd quarter of FY18 to confirm that the aging characteristic of Alloy 740H are the same as that for Alloy 617.

36 MATERIALS SCIENCE↗

NASA NTRS1972

Astronomical photography. Part A: Gum nebula, galactic cluster, and zodiacal light photography

It is reported that the Apollo 16 command module astronomical photography was performed with the specific objective of capitalizing on the uniqueness of the double umbra as a vantage point to collect astronomical data that are obtainable only near our Moon. For this reason, these data will be compared directly to analogous photography performed from Earth orbit during Project Mercury and the Gemini Program as well as to the Apollo-duplicated photography taken from sites on the Earth surface. Comparison with Earth-based photography should yield direct information on the Earth airglow layer and on atmospheric scattering and extinction.

Mercer, R. D.↗