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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 361 records · Page 20

All sources NASA NTRS DOE OSTI

NASA NTRS1993

Program Helps Decompose Complicated Design Problems

Time saved by intelligent decomposition into smaller, interrelated problems. DeMAID is knowledge-based software system for ordering sequence of modules and identifying possible multilevel structure for design problem. Displays modules in N x N matrix format. Requires investment of time to generate and refine list of modules for input, it saves considerable amount of money and time in total design process, particularly new design problems in which ordering of modules has not been defined. Program also implemented to examine assembly-line process or ordering of tasks and milestones.

Rogers, James L., Jr.↗

NASA NTRS1980

Investigation of proposed process sequence for the array automated assembly task, phases 1 and 2

Progress was made on the process sequence for module fabrication. A shift from bonding with a conformal coating to laminating with ethylene vinyl acetate and a glass superstrate is recommended for further module fabrication. The processes that were retained for the selected process sequence, spin-on diffusion, print and fire aluminum p+ back, clean, print and fire silver front contact and apply tin pad to aluminum back, were evaluated for their cost contribution.

Mardesich, N.↗

DOE OSTI2024

Positioning Accuracy in a Concurrent Robot-CNC Hybrid Manufacturing System

Abstract Additive manufacturing (AM) has gained notoriety for offering advantages over traditional manufacturing methods, such as increased design complexity and flexibility. However, it has not found widespread use beyond rapid prototyping. One hindrance to the acceptance of AM processes in industry is the time and cost of fabrication per component. While metal AM by itself can be inexpensive, extra manufacturing steps in the form of subtractive manufacturing (SM) may need to be performed to reach final part tolerances, leading to hybrid additive-subtractive manufacturing (HASM) of a part, which increases time and cost. A potential area to reduce cost is through increasing the efficiency of the HASM process by conducting additive and subtractive manufacturing simultaneously. Usually, HASM is performed in a process where AM is completed in one machine or cell and transferred to another machine or cell for SM in a sequential assembly line process. This efficiency decreases part cost, but high aspect ratio parts or parts with internal geometry that require interleaved additive deposition and machining cannot be produced. One unexplored solution to simultaneous HASM that allows for interleaved operations is to operate the deposition head and machining spindle concurrently within the same machine envelope, known as concurrent HASM (CHASM). In this type of process, both AM and SM occur simultaneously on a batch of small parts or a single large part, maintaining a high efficiency without sacrificing the full range of complex geometries that AM allows for. A potential approach to the single-machine method could be to combine a robot and mill within the same envelope. A challenge to this approach, however, is control of both systems. Most machine controllers have limited external communication or, if a robot has been integrated, only offer movement of either the robot or mill at any given time. As a result, systems must pause either the AM or SM process to switch between them rather than working simultaneously. The present work investigates the positional accuracy of such a CHASM system comprised of a robotic arm and a 3-axis mill. Open-loop tests with limited communication between machines are performed on the system to verify positional error during concurrent robot-mill movements. Under certain conditions, it is demonstrated that position error can stay within 2 mm for the duration of a single layer; however, these tests show that, generally, the open-loop positioning performance of the system is inadequate for CHASM without part-specific hand-tuning of parameters. Based on these results, a set of requirements for successful robot-CNC CHASM is proposed for future integrations.

Goodwin, Jesse↗

NASA NTRS1988

Processes for fabricating and load testing NASA scatterometer antenna assemblies

The purpose of this paper is to present the processes used to fabricate and load test the NASA Scatterometer Antenna Assemblies. The fabrication processes include layup, curing and machining of antenna components, and the bonding and assembly of the components into the final antenna configuration. The design of each antenna consists of an aluminum waveguide bonded to a sandwich structure of Nomex honeycomb core with graphite/epoxy skins. A titanium end fitting with fiberglass/epoxy transitions is bonded into one end of each antenna. Several antenna components are fabricated using a process where aluminum foil is co-cured to a composite surface. The antenna assemblies are radiographically inspected, thermally cycled, and load tested prior to shipment.

Barth, James R.↗

NASA NTRS1979

High-temperature microphone system

Pressure fluctuations in air or other gases in an area of elevated temperature are measured using a condenser microphone located in the area of elevated temperature and electronics for processing changes in the microphone capacitance located outside the area the area and connected to the microphone by means of high-temperature cable assembly. The microphone includes apparatus for decreasing the undesirable change in microphone sensitivity at high temperatures. The high temperature cable assembly operates as a half-wavelength transmission line in an AM carrier system and maintains a large temperature gradient between the two ends of the cable assembly. The processing electronics utilizes a voltage controlled oscillator for automatic tuning thereby increasing the sensitivity of the measuring apparatus.

Zuckerwar, A. J.↗

NASA NTRS1998

Parallel processing spacecraft communication system

An uplink controlling assembly speeds data processing using a special parallel codeblock technique. A correct start sequence initiates processing of a frame. Two possible start sequences can be used; and the one which is used determines whether data polarity is inverted or non-inverted. Processing continues until uncorrectable errors are found. The frame ends by intentionally sending a block with an uncorrectable error. Each of the codeblocks in the frame has a channel ID. Each channel ID can be separately processed in parallel. This obviates the problem of waiting for error correction processing. If that channel number is zero, however, it indicates that the frame of data represents a critical command only. That data is handled in a special way, independent of the software. Otherwise, the processed data further handled using special double buffering techniques to avoid problems from overrun. When overrun does occur, the system takes action to lose only the oldest data.

Bolotin, Gary S.↗

NASA NTRS2000

Dimpled ball grid array process development for space flight applications

A 472 dimpled ball grid array (D-BGA) package has not been used in past space flight environments, therefore it was necessary to develop a process that would yield robust and reliable solder joints. The process developing assembly, inspection and rework techniques, were verified by conducting environmental tests. Since the 472 D-BGA packages passed the above environmental tests within the specifications, the process was successfully developed for space flight electronics.

solder joints↗

NASA NTRSDate not supplied

A Thermal Review of the Sample Cartridge Assembly (SCA) Gravitational Effect of Distortion in Sintering (GEDS) Experiment Flight Processing

NASA’s Sample Cartridge Assembly (SCA) first flight experiment, Gravitational Effect of Distortion in Sintering (GEDS), was processed on the International Space Station (ISS) between 2019 and 2020. The SCA was heated in the European Space Agency’s (ESA) Low Gradient Furnace (LGF) that is housed inside the Material Science Research Rack (MSRR) located in the U.S. Laboratory Module. This summary will give a review of the design and flight experiment development for the GEDS SCA. It describes flight processing and the role of thermal engineering support. Lessons learned and future Principle Investigators (PI) will be discussed.

Micro-gravity Science↗

NASA NTRSDate not supplied

A Thermal Review of the Sample Cartridge Assembly (SCA) Gravitational Effect of Distortion in Sintering (GEDS) Experiment Flight Processing

MIcro-gravity Science↗

DOE OSTI2022

Robotic four-dimensional pixel assembly of van der Waals solids

Van der Waals (vdW) solids can be engineered with atomically precise vertical composition through the assembly of layered two-dimensional materials. However, the artisanal assembly of structures from micromechanically exfoliated flakes is not compatible with scalable and rapid manufacturing. Further engineering of vdW solids requires precisely designed and controlled composition over all three spatial dimensions and interlayer rotation. Here, we report a robotic four-dimensional pixel assembly method for manufacturing vdW solids with unprecedented speed, deliberate design, large area and angle control. We used the robotic assembly of prepatterned 'pixels' made from atomically thin two-dimensional components. Wafer-scale two-dimensional material films were grown, patterned through a clean, contact-free process and assembled using engineered adhesive stamps actuated by a high-vacuum robot. We fabricated vdW solids with up to 80 individual layers, consisting of 100 x 100 μm 2 areas with predesigned patterned shapes, laterally/vertically programmed composition and controlled interlayer angle. This enabled efficient optical spectroscopic assays of the vdW solids, revealing new excitonic and absorbance layer dependencies in MoS 2 . Furthermore, we fabricated twisted $N$-layer assemblies, where we observed atomic reconstruction of twisted four-layer WS 2 at high interlayer twist angles of >= 4°. In conclusion, our method enables the rapid manufacturing of atomically resolved quantum materials, which could help realize the full potential of vdW heterostructures as a platform for novel physics and advanced electronic technologies.

42 ENGINEERING↗

DOE OSTI2021

DOE JGI Metagenome Workflow

The DOE Joint Genome Institute (JGI) Metagenome Workflow performs metagenome data processing, including assembly; structural, functional, and taxonomic annotation; and binning of metagenomic data sets that are subsequently included into the Integrated Microbial Genomes and Microbiomes (IMG/M) (I.-M. A. Chen, K. Chu, K. Palaniappan, A. Ratner, et al., Nucleic Acids Res, 49:D751–D763, 2021, https://doi.org/10.1093/nar/gkaa939) comparative analysis system and provided for download via the JGI data portal (https://genome.jgi.doe.gov/portal/). This workflow scales to run on thousands of metagenome samples per year, which can vary by the complexity of microbial communities and sequencing depth. Here, we describe the different tools, databases, and parameters used at different steps of the workflow to help with the interpretation of metagenome data available in IMG and to enable researchers to apply this workflow to their own data. We use 20 publicly available sediment metagenomes to illustrate the computing requirements for the different steps and highlight the typical results of data processing. The workflow modules for read filtering and metagenome assembly are available as a workflow description language (WDL) file (https://code.jgi.doe.gov/BFoster/jgi_meta_wdl). The workflow modules for annotation and binning are provided as a service to the user community at https://img.jgi.doe.gov/submit and require filling out the project and associated metadata descriptions in the Genomes OnLine Database (GOLD) (S. Mukherjee, D. Stamatis, J. Bertsch, G. Ovchinnikova, et al., Nucleic Acids Res, 49:D723–D733, 2021, https://doi.org/10.1093/nar/gkaa983).

59 BASIC BIOLOGICAL SCIENCES↗

NASA NTRS1983

The variable polarity plasma arc welding process: Its application to the Space Shuttle external tank

The technical history of the variable polarity plasma arc (VPPA) welding process being introduced as a partial replacement for the gas shielded tungsten arc process in assembly welding of the space shuttle external tank is described. Interim results of the weld strength qualification studies, and plans for further work on the implementation of the VPPA process are included.

Nunes, A. C., Jr.↗

NASA NTRS2020

The Silicon Meta-shell X-ray Mirror Technology Development Roadmap for the Lynx Mission

This document presents a roadmap for advancing the silicon meta-shell optics (SMO). It describes an overall strategy and key technical elements to be developed to meet the four-fold Lynx requirements: (1) angular resolution, (2) effective area, (3) mass, and (4) production schedule and cost. It also describes the building and testing of an engineering unit whose successful completion will retire all risks, technical, logistical, schedule, and cost, associated with building and delivering a mirror assembly for the Lynx mission. All of this work, designed to advance this technology to TRL 6, will be completed by Preliminary Design Review (PDR) to ensure that the flight mirror assembly production process will be but a repetition of a set of well-defined and mature steps, leading to on-time and on-budget delivery of a mirror assembly for the Lynx mission.

Zhang, William W.↗

NASA NTRS1985

Putting the 'super' in supercomputers

Computers used for numerical simulations of physical phenomena, e.g., flowfields, meteorology, structural analysis, etc., replace physical experiments that are too expensive or impossible to perform. The problems considered continually become increasingly more complex and thus demand faster processing times to do all necessary computations. The effects components technologies have on computer speed are leveling off, leaving new architectures and programming as the only currently viable means to upgrade speed. Parallel computations, either in the form of array processors, assembly line processing or multiprocessors are being explored using existing microprocessor technologies. Slower hardware configurations can also be made equivalent to faster supercomputers by economic programming. The availability of rudimentary parallel architecture supercomputers for general industrial use is increasing. Scientific applications continue to drive the development of more sophisticated parallel machines.

Schulbach, C.↗

DOE OSTI2025

Depth-dependent Metagenome-Assembled Genomes of Agricultural Soils under Managed Aquifer Recharge

Abstract Managed Aquifer Recharge (MAR) systems, which intentionally replenish groundwater aquifers with excess water, are critical for addressing water scarcity exacerbated by demographic shifts and climate variability. To date, little is known about the functional diversity of the soil microbiome at different soil depth inhabiting agricultural soils used for MAR. Knowing the functional diversity is pivotal in regulating nutrient cycling and maintaining soil health. Metagenomics, particularly Metagenome-Assembled Genomes (MAGs), provide a powerful tool to explore the diversity of uncultivated soil microbes, facilitating in-depth investigations into microbial functions. In a field experiment conducted in a California vineyard, we sequenced soil DNA before and after water application of MAR. Through this process, we assembled 146 medium and 14 high-quality MAGs, uncovering a wide array of archaeal and bacterial taxa across different soil depths. These findings advance our understanding of the microbial ecology and functional diversity of soils used for MAR, contributing to the development of more informed and sustainable land management strategies.

Science & Technology - Other Topics↗

NASA NTRS2000

Affordable Design: A Methodolgy to Implement Process-Based Manufacturing Cost into the Traditional Performance-Focused Multidisciplinary Design Optimization

The primary objective of this paper is to demonstrate the use of process-based manufacturing and assembly cost models in a traditional performance-focused multidisciplinary design and optimization process. The use of automated cost-performance analysis is an enabling technology that could bring realistic processbased manufacturing and assembly cost into multidisciplinary design and optimization. In this paper, we present a new methodology for incorporating process costing into a standard multidisciplinary design optimization process. Material, manufacturing processes, and assembly processes costs then could be used as the objective function for the optimization method. A case study involving forty-six different configurations of a simple wing is presented, indicating that a design based on performance criteria alone may not necessarily be the most affordable as far as manufacturing and assembly cost is concerned.

Bao, Han P.↗

NASA NTRS1972

Effect of polarity of electric current on friction behavior of two gallium-lubricated tantalum slipring assemblies

Computer-processed data from low-speed (10 rpm) slipring experiments with two similar (but of opposite polarity) gallium-lubricated tantalum slipring assemblies (hemisphere against disk) carrying 50 amperes dc in vacuum (10 to the minus 9th power torr) showed that the slipring assembly with the anodic hemisphere had significantly lower peak-to-peak values and standard deviations of coefficient-of-friction samples (a measure of smoothness of operation) than the slipring assembly with the cathodic hemisphere. Similar data from an experiment with the same slipring assemblies running currentless showed more random differences in the frictional behavior between the two assemblies.

Przybyszewski, J.↗

DOE OSTI2021

Differential structure and functional gene response to geochemistry associated with the suspended and attached shallow aquifer microbiomes from the Illinois Basin, IL

Despite the clear ecological significance of the microbiomes inhabiting groundwater and connected ecosystems, our current understanding of their habitats, functionality, and the ecological processes controlling their assembly have been limited. In this study, an efficient pipeline combining geochemistry, high-throughput Fluidigm TM functional gene amplification and sequencing was developed to analyze the suspended and attached microbial communities inhabiting five groundwater monitoring wells in the Illinois Basin, USA. The dominant taxa in the suspended and the attached microbial communities exhibited significantly different spatial and temporal changes in both alpha- and beta-diversity. Further analyses of representative functional genes affiliated with N 2 fixation (nifH), methane oxidation (pmoA), and sulfate reduction (dsrB, and aprA), suggested functional redundancy within the shallow aquifer microbiomes. While more diversified functional gene taxa were observed for the suspended microbial communities than the attached ones except for pmoA, different levels of changes over time and space were observed between these functional genes. Notably, deterministic and stochastic ecological processes shaped the assembly of microbial communities and functional gene reservoirs differently. While homogenous selection was the prevailing process controlling assembly of microbial communities, the neutral processes (e.g., dispersal limitation, drift and others) were more important for the functional genes. The results suggest complex and changing shallow aquifer microbiomes, whose functionality and assembly vary even between the spatially proximate habitats and fractions. As a result, this research underscored the importance to include all the interface components for a more holistic understanding of the biogeochemical processes in aquifer ecosystems, which is also instructive for practical applications.

54 ENVIRONMENTAL SCIENCES↗