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All sources NASA NTRS DOE OSTI

DOE OSTI2016

Exclusive pi- Electroproduction off the Neutron in Deuterium in the Resonance Region

The goal of our research is to provide the exclusive γ*(n) → p+π− reaction cross section from deuterium data using the correction factor that account for the final state re-scattering that can be determined from the data set itself. The “e1e” Jefferson Lab CLAS data set that we analyze includes both a hydrogen and deuterium target run period, which allows a combined analysis of pion electroproduction off the free proton, the bound proton, and the bound neutron under the same experimental conditions. Hence it will provide the experimentally best possible information about the off-shell and final state interaction effects in deuterium, which must be considered in order to extract the neutron information. This data set will provide results with a kinematic coverage for the hadronic invariant mass W up to 1.7 GeV and in the momentum transfer Q2 range of 0.4 − 1.0 GeV/c2. The cross section analysis of this data set is currently underway, which will considerably improve our knowledge of the Q2 evolution of π−p electroproduction cross sections off bound neutron needed for the extraction of excited neutron state electrocouplings for the first time.

Tian, Ye↗

DOE OSTI2024

Graph-learning approach to combine multiresolution seismic velocity models

SUMMARY The resolution of velocity models obtained by tomography varies due to multiple factors and variables, such as the inversion approach, ray coverage, data quality, etc. Combining velocity models with different resolutions can enable more accurate ground motion simulations. Toward this goal, we present a novel methodology to fuse multiresolution seismic velocity maps with probabilistic graphical models (PGMs). The PGMs provide segmentation results, corresponding to various velocity intervals, in seismic velocity models with different resolutions. Further, by considering physical information (such as ray path density), we introduce physics-informed probabilistic graphical models (PIPGMs). These models provide data-driven relations between subdomains with low (LR) and high (HR) resolutions. Transferring (segmented) distribution information from the HR regions enhances the details in the LR regions by solving a maximum likelihood problem with prior knowledge from HR models. When updating areas bordering HR and LR regions, a patch-scanning policy is adopted to consider local patterns and avoid sharp boundaries. To evaluate the efficacy of the proposed PGM fusion method, we tested the fusion approach on both a synthetic checkerboard model and a fault zone structure imaged from the 2019 Ridgecrest, CA, earthquake sequence. The Ridgecrest fault zone image consists of a shallow (top 1 km) high-resolution shear-wave velocity model obtained from ambient noise tomography, which is embedded into the coarser Statewide California Earthquake Center Community Velocity Model version S4.26-M01. The model efficacy is underscored by the deviation between observed and calculated traveltimes along the boundaries between HR and LR regions, 38 per cent less than obtained by conventional Gaussian interpolation. The proposed PGM fusion method can merge any gridded multiresolution velocity model, a valuable tool for computational seismology and ground motion estimation.

Geochemistry & Geophysics↗

DOE OSTI2013

Clemson University CyberInstitute (Final Report)

The Clemson University CyberInstitute (CUCI - http://cyberinstitute.clemson.edu/) serves as a critically needed conduit for a “virtual research campus” of cyber resources and strengths at each of South Carolina’s research institutions in developing a cyberinfrastructure portfolio that advances South Carolina’s position in research, clinical, and economic development. CUCI will focus on the vision and strategy necessary for cyber-linked knowledge environments to develop and mature key partnerships and engagements from across the state that are enabled to leverage existing resources and take advantage of new knowledge and technologies. This project has four primary objectives: 1) increase research funding; 2) bridge academic researchers with corporate entities to expand technology transfer opportunities; 3) expand and broaden the use of cyberinfrastructure resources across South Carolina; and, 4) develop an education and workforce development program. The project has achieved many of its goals and objectives both programmatically and financially, and was successful at making tangible impacts in many areas.

Bottum, James R.↗

DOE OSTI2019

Investigation of Thermolytic Hydrogen Generation Rate in Tank 28 and Tank 39 Samples

This report contains hydrogen generation rate (HGR) measurements of Tank 28 and Tank 39 radioactive samples with and without added glycolate as a function of temperature. The objective of the Tank 28 and Tank 39 HGR measurements is to extend the knowledge from previous sample thermolysis HGR measurements and augment simulant testing for developing models for the Savannah River Site (SRS) Concentration, Storage, and Transfer Facilities (CSTF) thermolysis HGR with and without added glycolate. Tank 28 testing is applicable to concentrated salt supernate, legacy organic compounds resulting from the F-Canyon processes and boiling in the 3H-Evaporator System. Tank 39 testing is applicable to moderately concentrated salt supernate and organic compounds in fresh waste from the H-Canyon processes. For HGR tests with added sodium glycolate, the glycolate concentrations added to Tank 28 (500 mg/L) and Tank 39 (2000 mg/L) are based on concentrations expected to result in quantifiable HGR between temperatures of 70 °C and the atmospheric pressure boiling point. The added glycolate is much higher than the expected future glycolate concentrations in Tank 28, Tank 39, and similar CSTF tanks.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

NASA NTRS1983

Direct determination of surface albedos from satellite imagery

An empirical method to measure the spectral surface albedo of surfaces from Landsat imagery is presented and analyzed. The empiricism in the method is due only to the fact that three parameters of the solution must be determined for each spectral photograph of an image on the basis of independently known albedos at three points. The approach is otherwise based on exact solutions of the radiative transfer equation for upwelling intensity. Application of the method allows the routine construction of spectral albedo maps from satelite imagery, without requiring detailed knowledge of the atmospheric aerosol content, as long as the optical depth is less than 0.75, and of the calibration of the satellite sensor.

Mekler, Y.↗

NASA NTRS2004

The NASA Materials Science Research Program: It's New Strategic Goals and Opportunities

In the past year, the NASA s Office of Biological and Physical Research (OBPR) has formulated a long term plan to perform strategical and fundamental research bringing together physics, chemistry, biology, and engineering to solve problems needed for current and future agency mission goals. Materials Science is one of basic disciplines within the Enterprise s Division of Physical Sciences Research. The Materials Science Program participates to utilize effective use of International Space Station (ISS) and various world class ground laboratory facilities to solve new scientific and technology questions and transfer these results for public and agency benefits. The program has recently targeted new investigative research in strategic areas necessary to expand NASA knowledge base for exploration of the universe and some of these experiments will need access to the microgravity of space. The program is implementing a wide variety of traditional ground and flight based research related types of fundamental science related to materials crystallization, fundamental processing, and properties characterization in order to obtain basic understanding of various phenomena effects and relationships to the structures, processing, and properties of materials. , In addition new initiatives in radiation protection, materials for propulsion and In-space fabrication and repair focus on research helping the agency solve problems needed for future transportation into the solar system. A summary of the types and sources for this research is presented including those experiments planned for a low gravity environment. Areas to help expand the science basis for NASA future missions are described. An overview of the program is given including the scope of the current and future NASA Research Announcements with emphasis on new materials science initiatives. A description of the planned flight experiments to be conducted on the International Space Station program along with the planned facility class Materials Science Research Rack (MSRR) and Microgravity Glovebox (MSG) type investigations. Some initial results from the first three materials experiments are given.

Schlagheck, Ronald A.↗

DOE OSTI2018

UW Translational Imaging Biomarker and Therapeutic Development

The development and validation of radiotracers is a critical step in the clinical translation of molecular imaging and theranostics to support personalized medicine. The proposed program is to support such efforts by an interdisciplinary team of investigators at the University of Washington (UW) and Fred Hutchinson Cancer Research Center (FHCRC) and to provide opportunities for trainees to learn the spectrum of translational research in imaging biomarkers and therapeutic development. The proposed translational research projects include "Preclinical Evaluation of PET Imaging for Use in the Translation of Targeted Alpha Therapy of Blood-Related Cancers to Clinical Studies" (Project 1-Wilbur, leader); "Hypoxia Imaging: Radiopharmaceuticals, Preclinical Studies, Mechanisms and Clinical trials" (Project 2-Krohn, leader); and "Diagnostic Applications of Radiolabeled Biologics in Solid Tumors" (Project 3-Minoshima, leader). These projects use radiotracers with long half-lives, such as F-18, Zr-89, I-124, and At-211, that can potentially be handled commercially if translation research is successful. The proposed research method is to use an interdisciplinary 'team' of expert investigators and trainees working on a specific project for 1 or 2 years along the timeline and milestones set by the Program Directors. Each team includes 1) a clinician expert; 2) a radiochemistry expert; 3) an imaging or radiation therapy expert; 4) a physicist; 5) trainees; and 6) a UW technology transfer officer. Two groups of trainees will be involved: clinical and basic science (radiochemistry) trainees. Clinical trainees will be recruited from 3 training programs: Nuclear Medicine Resident Program; Radiology Residency Program; and Residency Program in Radiation Oncology. Basic science trainees will be graduate students from degree-awarding departments (chemistry, material sciences, bioengineering) or post-doctoral students (radiology, radiation oncology, or collaborating departments). A goal of training is to develop future investigators who will be able to conduct independent translational research with knowledge and expertise earned in this interdisciplinary team environment. To address clinically relevant questions, the program will organize regular brainstorming meetings participated by clinicians from various medical disciplines; program investigators; trainees; technology transfer officers to discuss medical questions, relevant targets, and technical feasibility. UW provides outstanding research and clinical facilities and resources that can be accessed by investigators. The Departments of Radiology and Radiation Oncology at UW have been at the forefront of translational imaging and therapeutics research efforts in cancer, neurological disorders, and cardiovascular diseases. This funding opportunity will solidify ongoing efforts of interdisciplinary collaborations at UW into a cohesive program that will train a new generation of investigators. This will, in turn, accelerate the translational potential of new radiotracers by rapid developments of proof-of-concept and first-in-man studies along with in vivo validations in a clinically relevant context.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

NASA NTRS2005

Heat Transfer and Thermal Stability Research for Advanced Hydrocarbon Fuel Technologies

In recent years there has been increased interest in the development of a new generation of high performance boost rocket engines. These efforts, which will represent a substantial advancement in boost engine technology over that developed for the Space Shuttle Main Engines in the early 1970s, are being pursued both at NASA and the United States Air Force. NASA, under its Space Launch Initiative s Next Generation Launch Technology Program, is investigating the feasibility of developing a highly reliable, long-life, liquid oxygen/kerosene (RP-1) rocket engine for launch vehicles. One of the top technical risks to any engine program employing hydrocarbon fuels is the potential for fuel thermal stability and material compatibility problems to occur under the high-pressure, high-temperature conditions required for regenerative fuel cooling of the engine combustion chamber and nozzle. Decreased heat transfer due to carbon deposits forming on wetted fuel components, corrosion of materials common in engine construction (copper based alloys), and corrosion induced pressure drop increases have all been observed in laboratory tests simulating rocket engine cooling channels. To mitigate these risks, the knowledge of how these fuels behave in high temperature environments must be obtained. Currently, due to the complexity of the physical and chemical process occurring, the only way to accomplish this is empirically. Heated tube testing is a well-established method of experimentally determining the thermal stability and heat transfer characteristics of hydrocarbon fuels. The popularity of this method stems from the low cost incurred in testing when compared to hot fire engine tests, the ability to have greater control over experimental conditions, and the accessibility of the test section, facilitating easy instrumentation. These benefits make heated tube testing the best alternative to hot fire engine testing for thermal stability and heat transfer research. This investigation used the Heated Tube Facility at the NASA Glenn Research Center to perform a thermal stability and heat transfer characterization of RP-1 in an environment simulating that of a high chamber pressure, regenerative cooled rocket engine. The first step in the research was to investigate the carbon deposition process of previous heated tube experiments by performing scanning electron microscopic analysis in conjunction with energy dispersive spectroscopy on the tube sections. This analysis gave insight into the carbon deposition process and the effect that test conditions played in the formation of deleterious coke. Furthermore, several different formations were observed and noted. One other crucial finding of this investigation was that in sulfur containing hydrocarbon fuels, the interaction of the sulfur components with copper based wall materials presented a significant corrosion problem. This problem in many cases was more life limiting than those posed by the carbon deposition process. The results of this microscopic analysis was detailed and presented at the December 2003 JANNAF Air-Breathing Propulsion Meeting as a Materials Compatibility and Thermal Stability Analysis of common Hydrocarbon Fuels (reference 1).

DeWitt, Kenneth↗

DOE OSTI2023

QCD running couplings and effective charges

Here we discuss our present knowledge of $\alpha_s$, the fundamental running coupling or effective charge of Quantum Chromodynamics (QCD). A precise understanding of the running of $\alpha_s(Q^2) $ at high momentum transfer, $Q$, is necessary for any perturbative QCD calculation. Equally important, the behavior of $\alpha_s$} at low $Q^2$ in the nonperturbative QCD domain is critical for understanding strong interaction phenomena, including the emergence of mass and quark confinement. The behavior of $\alpha_s(Q^2)$ at all momentum transfers also provides a connection between perturbative and nonperturbative QCD phenomena, such as hadron spectroscopy and dynamics. We first sketch the origin of the QCD coupling, the reason why its magnitude depends on the scale at which hadronic phenomena are probed, and the resulting consequences for QCD phenomenology. We then summarize latest measurements in both the perturbative and nonperturbative domains. New theory developments include the derivation of the universal nonperturbative behavior of $\alpha_s(Q^2)$ from both the Dyson-Schwinger equations and light-front holography. We also describe theory advances for the calculation of gluon and quark Schwinger functions in the nonperturbative domain and the relation of these quantities to $\alpha_s$. We conclude by highlighting how the nonperturbative knowledge of $\alpha_s$ is now providing a parameter-free determination of hadron spectroscopy and structure, a central and long-sought goal of QCD studies.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2016

Sustainable Ammonia Synthesis – Exploring the scientific challenges associated with discovering alternative, sustainable processes for ammonia production

Ammonia (NH 3 ) is essential to all life on our planet. Until about 100 years ago, NH 3 produced by reduction of dinitrogen (N 2 ) in air came almost exclusively from bacteria containing the enzyme nitrogenase.. DOE convened a roundtable of experts on February 18, 2016. Participants in the Roundtable discussions concluded that the scientific basis for sustainable processes for ammonia synthesis is currently lacking, and it needs to be enhanced substantially before it can form the foundation for alternative processes. The Roundtable Panel identified an overarching grand challenge and several additional scientific grand challenges and research opportunities: -Discovery of active, selective, scalable, long-lived catalysts for sustainable ammonia synthesis. -Development of relatively low pressure (<10 atm) and relatively low temperature (<200 C) thermal processes. -Integration of knowledge from nature (enzyme catalysis), molecular/homogeneous and heterogeneous catalysis. -Development of electrochemical and photochemical routes for N 2 reduction based on proton and electron transfer -Development of biochemical routes to N 2 reduction -Development of chemical looping (solar thermochemical) approaches -Identification of descriptors of catalytic activity using a combination of theory and experiments -Characterization of surface adsorbates and catalyst structures (chemical, physical and electronic) under conditions relevant to ammonia synthesis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2019

Investigation Of Thermolysis Hydrogen Generation Rate In Tank 38 And Tank 50 Waste Samples With Sodium Glycolate

This report contains hydrogen generation rate (HGR) measurements of Tank 38 and Tank 50 radioactive samples with and without added glycolate as a function of temperature. The objective of the Tank 38 and Tank 50 HGR measurements is to extend the knowledge from previous sample thermolysis HGR measurements and augment simulant testing for developing an equation for the Savannah River Site (SRS) Concentration, Storage, and Transfer Facility (CSTF) thermolysis HGR with and without added glycolate. Tank 38 testing is applicable to the 2H-Evaporator System and associated CSTF waste tanks. Tank 50 HGR measurement is applicable to CSTF tanks and the Saltstone Production Facility (SPF). The glycolate concentration used is based on what would be expected to be near the high-end concentration of glycolate (1570 mg/L in Tank 38 and 350 mg/L in Tank 50). The radioactive dose rate of the Tank 38 material was high enough to require use of the flow system in the Shielded Cells. Tank 50 material was less radioactive, so the higher temperatures were investigated in the flow system while the lower temperatures were investigated in the sealed system contained within a radiological hood.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

NASA NTRS1976

Optical observations of HDE 226868 = Cygnus X-1: A review

The present state of knowledge of the binary system HDE226868 = Cygnus X-1 is summarized, including system dimensions, nature of the secondary X-ray source, and mass transfer properties. Some deficiencies in the optical observations are pointed out; these deficiencies make interpretation of the system difficult, but can be corrected.

Bolton, C. T.↗

NASA NTRS2009

A Comprehensive Characterization of Microorganisms and Allergens in Spacecraft Environment

The determination of risk from infectious disease during long-duration missions is composed of several factors including the concentration and the characteristics of the infectious agent. Thus, a thorough knowledge of the microorganisms aboard spacecraft is essential in mitigating infectious disease risk to the crew. While stringent steps are taken to minimize the transfer of potential pathogens to spacecraft, several medically significant organisms have been isolated from both the Mir and International Space Station (ISS). Historically, the method for isolation and identification of microorganisms from spacecraft environmental samples depended upon their growth on culture media. Unfortunately, only a fraction of the organisms may grow on a culture medium, potentially omitting those microorganisms whose nutritional and physical requirements for growth are not met. Thus, several pathogens may not have been detected, such as Legionella pneumophila, the etiological agent of Legionnaire s disease. We hypothesize that environmental analysis using non-culture-based technologies will reveal microorganisms, allergens, and microbial toxins not previously reported in spacecraft, allowing for a more complete health assessment. The development of techniques for this flight experiment, operationally named SWAB, has already provided advances in NASA laboratory processes and beneficial information toward human health risk assessment. The translation of 16S ribosomal DNA sequencing for the identification of bacteria from the SWAB experiment to nominal operations has increased bacterial speciation of environmental isolates from previous flights three fold compared to previous conventional methodology. The incorporation of molecular-based DNA fingerprinting using repetitive sequence-based polymerase chain reaction (rep-PCR) into the capabilities of the laboratory has provided a methodology to track microorganisms between crewmembers and their environment. Both 16S ribosomal DNA identification and bacterial fingerprinting have improved NASA s capability to better understand spacecraft environments and determine the source of contamination events. Preflight sampling has been completed for air, surface, and water samples. In-flight sample collection has been completed for a total of 8 air and surface sample collection sessions. In-flight hardware has performed well and the surface sampling device received positive feedback from the crew for its ease of use. While processing and analysis continue for these samples, early results have begun to provide information on the spacecraft environment. Using a method called Denaturing Gradient Gel Electrophoresis (DGGE), several air and samples were evaluated to determine the types of organisms that were present. Using only molecular techniques, DGGE does not depend on any microbial growth on culture media, allowing a more comprehensive assessment of the spacecraft interior. Preliminary results have identified several microorganisms that would not have been isolated using current technology, though none of these organisms would be considered medically significant. Interestingly, the isolation of Gram negative organisms is greater using DGGE than conventional media based isolation. The cause of this finding is unclear, though it may be the result of the technique s ability to isolate both viable and non-viable bacteria. The next phase of the SWAB sample analysis is the use of quantitative polymerase chain reaction (QPCR) to look for specific medically significant organisms. While not as broad as DGGE, QPCR is much more sensitive and may reveal findings that were not seen during the initial evaluation. Together, this information will lead toward an accurate microbial risk assessment to help set flight requirements to protect the safety, health, and performance of the crew.

Castro, V.A.↗

DOE OSTI2019

Stripping off the implementation complexity of physics-based model predictive control for buildings via deep learning

Over the past decade, model predictive control (MPC) has been considered as the most promising solution for intelligent building operation. Despite extensive effort, transfer of this technology into practice is hampered by the need to obtain an accurate controller model with minimum effort, the need of expert knowledge to set it up, and the need of increased computational power and dedicated software to run it. A promising direction that tackles the last two problems was proposed by approximate explicit MPC where the optimal control policies are learned from MPC data via a suitable function approximator, e.g., a deep learning (DL) model. The main advantage of the proposed approach stems from simple evaluation at execution time leading to low computational footprints and easy deployment on embedded HW platforms. We present the energy savings potential of physics-based (also called 'white-box') MPC applied to an office building in Belgium. Moreover, we demonstrate how deep learning approximators can be used to cut the implementation and maintenance costs of MPC deployment without compromising performance. We also critically assess the presented approach by pointing out the major challenges and remaining open-research questions.

Drgona, Jan↗

DOE OSTI2020

The Intern Professional Development Center: A Model for Improving Student Engagement Within Industry - 20006

Many innovations and technical improvements have been made over the last half-century regarding our understanding of nuclear materials, with some of the brightest minds in the world collectively working towards a cleaner, brighter, healthier future. However, there is a demographical oddity with the enormous technical workforce that helped shape this new world: they are aging, collectively. Known as the 'silver tsunami,' mass retirements are in the near future for many technical industries, something that the industrial community is not entirely prepared to accommodate. There is an urgent need for a tech-savvy generation to replace the baby boomers, and there must be an uninterrupted hand-off from one generation to the next of institutional knowledge and best practices. Further, it is not enough to simply replace every retiring engineer with a younger one in a 'cold hand-off' - this information transfer takes time. Many educational communities, such as those in the Tri-Cities, Washington, are rising to the challenge, with STEM-focused programs, introducing students to technical concepts and potential career opportunities at an early age. However, while individually, academic institutions search for internships and industry has open positions for interested students, no single clearinghouse exists in the Mid-Columbia region to match talent with opportunities, regardless of the sending or receiving organizations. To fill this void, AYB Drafting (AYB) has established a career development and personal growth center, the Intern Professional Development Center (IPDC). The IPDC, located in Richland, Washington, addresses the problem of what has been referred to as the 'Graying of America,' as it bridges the gap between education and career for the up and coming workforce, creating valuable efficiencies for the young workforce and the industry alike. The operating principles and details of the initial IPDC launch are discussed in the following text, as well as the apparent success and overwhelming positive feedback received in just the first year of operation. (authors)

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗

NASA NTRS1999

Sensitivity of Temperature Profiles Retrieved from Mars Global Surveyor Thermal Emission Spectrometer (MGS/TES) Observations to the GSFC Synthetic Mars Model Atmosphere

Part of the task of interpreting IR spectral features observed by MGS/TES due to surface minerals requires distinguishing those IR signatures from atmospheric signatures of gas and dust. Surface-atmosphere separation for MGS/TES depends on knowledge of the retrieved temperature profile. In turn, the temperature retrieval Erom the observed data depends on molecular parameters including 15 micron CO2 line shape or line intensities which contribute to defining the Mars synthetic radiative transfer model. Using a simple isothermal, homogeneous single layer model of Pinnock and Shine, we find the ratio of (the error in degrees Kelvin of the retrieved temperature profile) to (the percentage error in the absorption coefficient) (deg K/percent) to be 0.4 at 200K. This ratio at 150K and 250K is 0.2 and 0.6, respectively. A more refined model, incorporating observed MGS/TES retrieved temperature profiles, the TES instrumental resolution and the most recent molecular modelling, will yield an improved knowledge of this error sensitivity. We present results of such a sensitivity study to determine the dependence of temperature profiles inverted from MGS/TES on these and other molecular parameters. This work was supported in part by NASA's Mars Data Analysis Program.

Maguire, William C.↗

DOE OSTI2020

Nuclear Data Sheets for A=233

The present evaluation of the known A=233 nuclides ( 233 Fr, 233 Ra, 233 Ac, 233 Th, 233 Pa, 233 U, 233 Np, 233 Pu, 233 Am, 233 Cm) and 233 Bk represents an update and revision, after 15 years of the previous evaluation of A=233 published by B. Singh and J.K. Tuli (2005Si15). Laboratory identification of 233 Bk nuclide is still considered as tentative. Various decay and reaction data are evaluated and compared. Adopted data, levels, gammas, level half-lives, spins, parities, and configuration assignments are provided. For 233 Fr, 233 Ra, 233 Ac, 233 Pu, 233 Am and 233 Cm, information is available for the respective ground states only. The decay schemes from β - decays of 233 Fr and 233 Ra, and from ε decay of 233 Am and 233 Cm are unknown, while those from β - decay of 233 Ac, and from ε decay of 233 Np are considered incomplete. The α decay of 237 Np to 233 Pa has been studied in detail by many investigators, yet the decay scheme is considered incomplete as several very low-energy transitions are involved, without the knowledge of their intensities, resulting in mismatch of directly measured α feedings and those deduced from γ-transition intensity balances. The decay schemes from α decays of 237 Am, 237 Cm and 237 Cf to respective A=233 daughters are considered incomplete. Particle-transfer and high-spin data are available for 233 Th, 233 Pa and 233 U nuclei, which remain the most extensively studied in this mass chain. However, data for half-lives for the excited states are available only for one level in 233 Pa, and for five levels in 233 U, thus limiting the knowledge of reduced transition probabilities in this mass chain.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2015

Experiment attributes to establish tube with twisted tape insert performance cooling plasma facing components

The modeling capability for tubes with twisted tape inserts is reviewed with reference to the application of cooling plasma facing components in magnetic confinement fusion devices. The history of experiments examining the cooling performance of tubes with twisted tape inserts is reviewed with emphasis on the manner of heating, flow stability limits and the details of the test section and fluid delivery system. Models for heat transfer, burnout, and onset of net vapor generation in straight tube flows and tube with twisted tape are compared. As a result, the gaps in knowledge required to establish performance limits of the plasma facing components are identified and attributes of an experiment to close those gaps are presented.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗