Search NASA⌕ Search

SEARCH · Search NASA

Results for “Direct Processes”

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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

Retinex Image Processing: Improved Fidelity to Direct Visual Observation

Recorded color images differ from direct human viewing by the lack of dynamic range compression and color constancy. Research is summarized which develops the center/surround retinex concept originated by Edwin Land through a single scale design to a multi-scale design with color restoration (MSRCR). The MSRCR synthesizes dynamic range compression, color constancy, and color rendition and, thereby, approaches fidelity to direct observation.

Jobson, Daniel J.↗
DOE OSTI2025

Approaches for Water Removal in Direct-Fired sCO 2 Power Cycles

There is interest in investigation of water removal processes in direct fired sCO 2 flows, as this may potentially lead to greater system efficiency as the removal of this contaminant will result in sCO 2 behaving close to idealized behaviors. Water removal should be split into a two-step process, condensation of the water, followed by separation of the liquid phase water from the sCO 2 . The two main avenues of condensation are manipulation of pressure and temperature for phase change. For this paper, temperature-based phase change is the primary focus through the implementation of heat exchangers. Of the heat exchangers investigated it was found that printed circuit heat exchangers (PCHEs) could be an alternative for this use case, though the specific design of flow channel geometry and flow direction depends on the specific system case and cannot be determined at this point. For water separation there were four processes identified, all of which already assume water is in liquid phase at that point in the system. Of these separation avenues the best candidate is the hydrocyclone as it has a proven history of separating liquid-liquid phase mixtures with small density differences in oilfield use, in addition they have been investigated and modeled specifically for water separation for sCO 2 flows and the footprint is relatively small.

20 FOSSIL-FUELED POWER PLANTS↗
NASA NTRSDate not supplied

AM Processes Part 2: Principles of Directed Energy Deposition

Directed Energy Deposition (DED) is one of the metal additive manufacturing processes which finds wider industrial applications, particularly for repair and reclamation, and for large structures. This course helps the attendees to understand the fundamental concepts of DED process and covers the topics such as, how the technology works, different DED processes, materials used, and typical applications where this technology is used. The discussion will have a focus on ASTM F3187 – Standard guide for Directed Energy Deposition of Metals. After completing this webinar the attendees will achieve the following: · Identify and understand the different types of DED processes · Understand how to select a DED process and trade criteria · Understand the various materials used for DED processes · Understand the core parameters for the DED processes · Determine potential parts and end application of DED technology

Additive Manufacturing↗
DOE OSTI2020

Enhanced Sustainability in Treatment of Contaminated Metals for Clearance and Recycling - 20290

Cyclife Sweden AB has, for more than 30 years, provided metal treatment services to the domestic and international nuclear industry with the aim of creating value through metal clearance and recycling. These operations are to a large extent based on the concept that the materials, after pre-treatment, including decontamination, will be melted for clearance. During the melting process, some nuclides separate from the metal while the remaining radioactivity becomes fully homogenized in the metal bath and the resulting ingots, along with the samples taken before casting At a time when activities to fight Climate Challenge are in focus, any savings in energy consumption, in addition to the positive environmental effect of recycling metals back to industry, is more than welcome. If the clearance of certain metallic items can be achieved safely, without using melting, it is the environmentally preferred option provided it carries a reasonable cost. It is even better if an object can go through a decontamination and clearance process prior to re-use inside or outside the nuclear sector. Cyclife Sweden is currently investing in a direct clearance process, to be operated in parallel with the melting process. This new process is expected to be fully operational in the late summer of 2020 and includes pre-treatment, decontamination and heavily shielded clearance measurement installations. The treatment will also allow clearance measurements of larger objects without the need for segmentation, along with allowing objects composed of different materials, like electric motors can be accepted for treatment. This paper gives an overview of the circular economy aspects in a nuclear back-end context, the Cyclife approach to further implement a circular economy approach in the processes, Material Acceptance Criteria for treatment, the facility set-up for the new process and how the melting route and the direct route can be combined in an efficient industrial scale process. To put the new capabilities into perspective, the two different treatment and clearance approaches, i.e. direct clearance and melting, are to be compared. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

Physics Prospects for a near-term Proton-Proton Collider

Hadron colliders at the energy frontier offer significant discovery potential through precise measurements of Standard Model processes and direct searches for new particles and interactions. A future hadron collider would enhance the exploration of particle physics at the electroweak scale and beyond, potentially uniting the community around a common project. The LHC has already demonstrated precision measurement and new physics search capabilities well beyond its original design goals and the HL-LHC will continue to usher in new advancements. This document highlights the physics potential of an FCC-hh machine to directly follow the HL-LHC. In order to reduce the timeline and costs, the physics impact of lower collider energies, down to $\sim 50$~TeV, is evaluated. Lower centre-of-mass energy could leverage advanced magnet technology to reduce both the cost and time to the next hadron collider. Such a machine offers a breadth of physics potential and would make key advancements in Higgs measurements, direct particle production searches, and high-energy tests of Standard Model processes. Most projected results from such a hadron-hadron collider are superior to or competitive with other proposed accelerator projects and this option offers unparalleled physics breadth. The FCC program should lay out a decision-making process that evaluates in detail options for proceeding directly to a hadron collider, including the possibility of reducing energy targets and staging the magnet installation to spread out the cost profile.

FOS: Physical sciences↗
NASA NTRS2005

The Pore Formation and Mobility Investigation: A Case Study for Conducting Research on the International Space Station in Support of Exploration

The Pore Formation and Mobility Investigation (PFMI) is being conducted in the Microgravity Science Glovebox (MSG) aboard the International Space Station (ISS) with the goal of understanding bubble generation and interactions during controlled directional solidification processing. Through the course of the experiments, beginning in September 2002, a number of key factors pertinent to solidification processing of materials in a microgravity environment have been directly observed, measured, and modeled. Though most experiments ran uninterrupted, on four separate occasions malfunctions to the PFMI hardware and software were experienced that required crew intervention, including in-space repair. Fortunately, each repair attempt was successful and restored the PFMI apparatus to a fully functional condition. Based on PFMI results and lessons learned, the intent of this presentation is to draw attention to the role ISS experiments/hardware can play in providing insight to potential fabrication processing techniques and repair scenarios that might arise during long duration space transport and/or on the lunar/Mars surface.

Grugel, R. N.↗
NASA NTRS2006

The Pore Formation and Mobility Investigation: A Summary of Conducted Research on the International Space Station

The Pore Formation and Mobility Investigation (PFMI) is being conducted in the Microgravity Science Glovebox (MSG) aboard the International Space Station (ISS) with the goal of understanding bubble generation and interactions during controlled directional solidification processing. Through the course of the experiments, beginning in September 2002, a number of key factors pertinent to solidification processing of materials in a microgravity environment have been directly observed, measured, and modeled. Though most experiments ran uninterrupted, on four separate occasions malfunctions to the PFMI hardware and software were experienced that required crew intervention, including in-space repair. Fortunately, each repair attempt was successful and restored the PFMI apparatus to a fully functional condition. Based on PFMI results and lessons learned, the intent of this presentation is to draw attention to the role ISS experiments/hardware can play in providing insight to potential fabrication processing techniques and repair scenarios that might arise during long duration space transport and/or on the lunar/Mars surface.

Grugel, R. N.↗
NASA NTRS1971

Spaceborne electronic imaging systems

Criteria and recommended practices for the design of the spaceborne elements of electronic imaging systems are presented. A spaceborne electronic imaging system is defined as a device that collects energy in some portion of the electromagnetic spectrum with detector(s) whose direct output is an electrical signal that can be processed (using direct transmission or delayed transmission after recording) to form a pictorial image. This definition encompasses both image tube systems and scanning point-detector systems. The intent was to collect the design experience and recommended practice of the several systems possessing the common denominator of acquiring images from space electronically and to maintain the system viewpoint rather than pursuing specialization in devices. The devices may be markedly different physically, but each was designed to provide a particular type of image within particular limitations. Performance parameters which determine the type of system selected for a given mission and which influence the design include: Sensitivity, Resolution, Dynamic range, Spectral response, Frame rate/bandwidth, Optics compatibility, Image motion, Radiation resistance, Size, Weight, Power, and Reliability.

Source record↗
NASA NTRS1995

Frequency-Channelized SAR Processing For Multiple Angle Looks

Technique for processing synthetic-aperture-radar (SAR) signals exploits fact that center frequency of frequency channel of data being processed linked directly to squint angle and to azimuth angle. Also exploits fact in multilook SAR data processing, total bandwidth of each SAR polarization channel divided into N (typically, N = 16) equal frequency channels, data in each of which processed separately. Technique has yielded data on directionality of radar back scatter from agricultural fields.

Dubois, Pascale C.↗
NASA NTRS2012

Finite Element Models for Electron Beam Freeform Fabrication Process

Electron beam freeform fabrication (EBF3) is a member of an emerging class of direct manufacturing processes known as solid freeform fabrication (SFF); another member of the class is the laser deposition process. Successful application of the EBF3 process requires precise control of a number of process parameters such as the EB power, speed, and metal feed rate in order to ensure thermal management; good fusion between the substrate and the first layer and between successive layers; minimize part distortion and residual stresses; and control the microstructure of the finished product. This is the only effort thus far that has addressed computer simulation of the EBF3 process. The models developed in this effort can assist in reducing the number of trials in the laboratory or on the shop floor while making high-quality parts. With some modifications, their use can be further extended to the simulation of laser, TIG (tungsten inert gas), and other deposition processes. A solid mechanics-based finite element code, ABAQUS, was chosen as the primary engine in developing these models whereas a computational fluid dynamics (CFD) code, Fluent, was used in a support role. Several innovative concepts were developed, some of which are highlighted below. These concepts were implemented in a number of new computer models either in the form of stand-alone programs or as user subroutines for ABAQUS and Fluent codes. A database of thermo-physical, mechanical, fluid, and metallurgical properties of stainless steel 304 was developed. Computing models for Gaussian and raster modes of the electron beam heat input were developed. Also, new schemes were devised to account for the heat sink effect during the deposition process. These innovations, and others, lead to improved models for thermal management and prediction of transient/residual stresses and distortions. Two approaches for the prediction of microstructure were pursued. The first was an empirical approach involving the computation of thermal gradient, solidification rate, and velocity (G,R,V) coupled with the use of a solidification map that should be known a priori. The second approach relies completely on computer simulation. For this purpose a criterion for the prediction of morphology was proposed, which was combined with three alternative models for the prediction of microstructure; one based on solidification kinetics, the second on phase diagram, and the third on differential scanning calorimetry data. The last was found to be the simplest and the most versatile; it can be used with multicomponent alloys and rapid solidification without any additional difficulty. For the purpose of (limited) experimental validation, finite element models developed in this effort were applied to three different shapes made of stainless steel 304 material, designed expressly for this effort with an increasing level of complexity. These finite element models require large computation time, especially when applied to deposits with multiple adjacent beads and layers. This problem can be overcome, to some extent, by the use of fast, multi-core computers. Also, due to their numerical nature coupled with the fact that solid mechanics- based models are being used to represent the material behavior in liquid and vapor phases as well, the models have some inherent approximations that become more pronounced when dealing with multi-bead and multi-layer deposits.

Chandra, Umesh↗
DOE OSTI2024

Direct Air Capture of CO 2 via Reactive Crystallization

Atmospheric CO 2 removal using engineered chemical processes, aka direct air capture (DAC), has become an essential component of our available portfolio for mitigating climate change. Here we describe a promising approach to DAC based on reactive crystallization of atmospheric CO 2 (RC-DAC) with aqueous guanidine and amino acid. Compared to the previously studied phase-changing DAC processes involving initial CO 2 absorption by an aqueous alkaline solvent followed by carbonate crystallization in a second step, RC-DAC combines the CO 2 absorption and carbonate crystallization into a single step. Thus, as the insoluble carbonate salts are removed from solution by crystallization, more CO 2 is pulled from the air into solution, further driving the DAC process. The RC-DAC was performed in a household humidifier as the air–liquid contactor, which can handle solid–liquid slurries effectively. The crystallization was monitored in situ by pH measurements, real-time imaging with a microscope probe, and by Raman spectroscopy, and ex situ by NMR spectroscopy, powder X-ray diffraction, and total inorganic carbonate analysis. Further, the investigation provided a detailed mechanistic picture of the RC-DAC process, involving formation of carbamate and carbonate anions in solution, followed by sequential crystallization of different guanidinium carbonate phases.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Evolutionary reinforcement learning of dynamical large deviations

In this work, we show how to bound and calculate the likelihood of dynamical large deviations using evolutionary reinforcement learning. An agent, a stochastic model, propagates a continuous-time Monte Carlo trajectory and receives a reward conditioned upon the values of certain path-extensive quantities. Evolution produces progressively fitter agents, potentially allowing the calculation of a piece of a large-deviation rate function for a particular model and path-extensive quantity. For models with small state spaces, the evolutionary process acts directly on rates, and for models with large state spaces, the process acts on the weights of a neural network that parameterizes the model's rates. This approach shows how path-extensive physics problems can be considered within a framework widely used in machine learning.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1993

Achieving high data reduction with integral cubic B-splines

During geometry processing, tangent directions at the data points are frequently readily available from the computation process that generates the points. It is desirable to utilize this information to improve the accuracy of curve fitting and to improve data reduction. This paper presents a curve fitting method which utilizes both position and tangent direction data. This method produces G(exp 1) non-rational B-spline curves. From the examples, the method demonstrates very good data reduction rates while maintaining high accuracy in both position and tangent direction.

Chou, Jin J.↗