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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

A SIMPLE TOOL TO EVALUATE COLOR FOR LEGIBILITY AND DISTINGUISHABILITY WHEN DESIGNING DIGITAL DISPLAYS

Color is important in helping users effectively process information like text and symbols when performing tasks on digital displays. Interface designers in safety- and mission-critical industries often utilize human factors design guidelines and standards to make important design decisions like the use of color for legibility and distinguishability. However, such guidance sometimes requires additional interpretation and calculation to readily apply to the design question at hand. This work describes a simple tool that can be used to evaluate the adequacy of color choices from a palette for being legible or distinguishable. The tool eliminates having to manually convert colors to a readable format while providing a specific set of colors that are acceptable from select human factors standards. This paper provides an exemplary case study applied to a digital modification at a nuclear power plant to highlight how the tool may be used in safety and mission-critical industries.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2019

Impact of Radical Hysterectomy Versus Simple Hysterectomy on Survival of Patients with Stage 2 Endometrial Cancer: A Meta-analysis

Background: The strategy of radical surgery for stage 2 endometrial cancer (EC) remains controversial. This meta-analysis aimed to investigate the impact of radical hysterectomy (RH) versus simple hysterectomy (SH) on survival of patients with stage 2 EC. Methods: A systematic review was conducted to identify studies comparing survival between RH and SH in International Federation of Gynecology and Obstetrics (FIGO) stage 2 EC patients by searching several databases to July 2018. Hazard ratios (HRs) with 95% confidence intervals (CIs) for overall survival and progression-free survival were pooled using Stata V.12.0. Results: The study included 10 retrospective cohort studies enrolling 2866 patients. Patients who received RH did not show a significant survival benefit for either overall survival (pooled HR 0.92; 95% CI 0.72–1.16; P = 0.484) or progression-free survival (pooled HR 0.75; 95% CI 0.39–1.42; P = 0.378). The result remained consistent after it was balanced with possible impact from adjuvant radiotherapy (pooled HR 0.85; 95% CI 0.62–1.16; P = 0.300). In earlier studies that staged patients according to FIGO 1988, RH showed a 27% survival benefit (pooled HR 0.73; 95% CI 0.53–1.00; P = 0.050), whereas in newly published studies based on FIGO 2009 staging, it reversely showed increased risk of death (pooled HR 1.24; 95% CI 0.86–1.77; P = 0.245). However, no statistical significance was reached under either staging criterion. Conclusions: Based on the results of this meta-analysis, RH does not significantly improve survival in stage 2 EC. The choice of RH remains controversial and should be considered carefully in clinical practice. More qualified studies are needed to determine the best treatment strategy for stage 2 EC.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2025

Mechanical response of HFIR-irradiated M5FRAMATOME cladding under simple and complex loading conditions

This study investigates the mechanical behavior of High Flux Isotope Reactor (HFIR) irradiated M5FRAMATOME cladding under simple and complex loading conditions through axial tensile and reversible cyclic bending. Axial tension specimens were pre-machined prior to HFIR irradiation while cyclic bend specimens were inserted as intact tubes. Tests articles were neutron-irradiated to 4 and 16 dpa, and specimens were tested at ORNL's hotcell facilities. The axial tension tests were conducted under constant displacement control, and the reversible cyclic bend tests were performed using ORNL's Cyclic Integrated Reversible-Bending Fatigue Tester (CIRFT) apparatus. Results showed that mechanical response of Cr-coated and uncoated M5FRAMATOME cladding were similar and independent of irradiation dose for axial tension tests, while Cr-coated specimens’ reversible cyclic bend behavior differed from uncoated counterparts. For all tests, irradiation temperature showed a significant impact on the mechanical behavior. Below 280°C, all axial tensile specimens whether coated or not behaved similarly. Above 280°C, YS and UTS showed decrease with increasing irradiation temperature. A similar behavior was also observed in cyclic bend tests as well. The mechanical damage during cyclic bend tests was linked to damage accumulation in unirradiated Cr-coated zircaloy-4 specimens, and the effect of irradiation temperature was related to changing characteristics of defect mobility during high temperature irradiation.

Cinbiz, Nedim [ORNL] (ORCID:0000000346268515)↗
DOE OSTI2017

Split in phase singularities of an optical vortex by off-axis diffraction through a simple circular aperture

Here, diffraction patterns of an optical vortex through several shaped apertures reveal its topological charge. In this letter, we theoretically and experimentally show that diffraction of a Laguerre Gaussian beam through a circular aperture at an off-axis position can be used to determine the magnitude and sign of the topological charge. To our knowledge, this is the first time that a simple circular aperture has been used to detect orbital angular momentum of an incident optical vortex.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Ten Simple Rules to becoming a principal investigator

The biggest choke point in an academic career is going from postdoc to principal investigator (PI), moving from doing someone else’s research to getting other people to do yours. It is not an easy transition, draws on few of the skills you learn at the bench and the odds are clearly not ever in your favour. So calling this article ten simple rules is obviously a simplification: it is more accurate to call them ten tricky steps. In this article, we use Principal Investigator to mean anyone who runs their own research group, using funding that they have been awarded to answer their own questions. PI encompasses a number of different job titles depending on where the research is performed – fellow, lecturer, associate professor, senior scientist. The acid test is whether you can describe the people working for you as the X group, where X is your surname. The normal route from undergraduate to lab head involves a PhD, one or most postdoc positions and then PI. Given the diversity of ways to be a PI, the final step up from postdoc takes a number of forms – in the UK this tends to be either an individual fellowship or a lecturer position, in the US it generally starts with an independent position with associated funding – either as a startup package or funded grant. The aim of this article is to identify some of the broader skills (rules 1-4) and behaviours (rules 5-10) that can help with becoming a PI. They are meant as advice, not instruction. As you will see, most of them are soft/ leadership skills, which can as easily be applied to the world outside academia as within it.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2022

Ten simple rules for getting and giving credit for data

This article attempts to summarize current best practices that support the movement towards enabling researchers to cite and receive credit for their data. The authors are a small representation of the people and organizations trying to make this happen, and we acknowledge that it is not possible to capture all efforts behind this endeavor in 10 Simple Rules. We encourage interested readers to dive deeper by providing related resources along the way.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Optode performance data associated with: Metabolic Multireactor: practical considerations for using simple oxygen sensing optodes for high-throughput batch reactor metabolism experiments

This data package is associated with the publication “Metabolic Multireactor: practical considerations for using simple oxygen sensing optodes for high-throughput batch reactor metabolism experiments”, submitted to PlosONE (Kaufman et al. 2023; 10.1101/2023.03.28.534656).We carried out many testing and calibration experiments on a system of small oxygen consumption batch reactors designed for use with water and sediment samples for environmental questions. The oxygen sensing system is based very directly on the work of Larsen, et al. [2011], and similar oxygen sensing technology is widely used in the literature. Our primary focus was on practical considerations, such as temperature effects, lighting angle effects, sterilization, and other similar situations that a user may find useful. Most of the tests required comparing “base” calibration curves to “treatment” calibration curves to determine the extent to which the treatment impacted the reported measurements. This data package contains the performance and calibration data collected for that purpose.This dataset is comprised of one data folder containing (1) file-level metadata; (2) data dictionary; (3) readme; (4) diffusion test result files; (5) limit of detection test result files; (6) temperature impact files; (7) a main data file that contains test results for all other tests; and (8) an R script that uses Kolmogorov-Smirnov tests to determine whether treatment calibrations are significantly different from their respective base calibrations. All files are .csv, .txt, .Rmd, or .pdf.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

A simple method for obtaining heat capacity coefficients of minerals

Abstract Heat capacity data are unavailable or incomplete for many minerals at geologically relevant temperatures. Despite the availability of entropy and enthalpy values in numerous thermodynamic tables (even sometimes at elevated temperatures), there remains need for extrapolation beyond, or interpolation between, temperatures. This approach inevitably results in estimates for entropy and enthalpy values because the heat capacity coefficients required for optimal thermodynamic treatment are less frequently available. Here we propose a simple method for obtaining heat capacity coefficients of minerals. This method requires only the empirically measured temperature-specific heat capacity for calculation via a matrix algorithm. The system of equations solver is written in the Python computing language and has been made accessible in an online repository. Thermodynamically, the solution to a system of equations represents the heat capacity coefficients that satisfy the mineral-specific polynomial. Direct coefficient calculation will result in more robust thermodynamic data, which are not subject to fitting uncertainties. Using hematite as an example, this method provides results that are comparable to conventional means and is applicable to any solid material. Coefficients vary within the traditional large 950 K temperature interval, indicating that best results should instead utilize a smaller 400 K temperature interval. Examples of large-scale implications include the refinement of geothermal gradient estimation in rapidly subsiding sedimentary basins or metamorphic and hydrothermal evolution.

Geochemistry & Geophysics↗
DOE OSTI2023

A simple coin for a 2d entangled walk

We analyze the effect of a simple coin operator, built out of Bell pairs, in a 2d Discrete Quantum Random Walk (DQRW) problem. The specific form of the coin enables us to find analytical and closed form solutions to the recursion relations of the DQRW. The coin induces entanglement between the spin and position degrees of freedom, which oscillates with time and reaches a constant value asymptotically. We probe the entangling properties of the coin operator further, by two different measures. First, by integrating over the space of initial tensor product states, we determine the Entangling Power of the coin operator. Secondly, we compute the Generalized Relative Rényi Entropy between the corresponding density matrices for the entangled state and the initial pure unentangled state. Both the Entangling Power and Generalized Relative Rényi Entropy behaves similar to the entanglement with time. Finally, in the continuum limit, the specific coin operator reduces the 2d DQRW into two 1d massive fermions coupled to synthetic gauge fields, where both the mass term and the gauge fields are built out of the coin parameters.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2017

Evaluation of a Class of Simple and Effective Uncertainty Methods for Sparse Samples of Random Variables and Functions

When very few samples of a random quantity are available from a source distribution of unknown shape, it is usually not possible to accurately infer the exact distribution from which the data samples come. Under-estimation of important quantities such as response variance and failure probabilities can result. For many engineering purposes, including design and risk analysis, we attempt to avoid under-estimation with a strategy to conservatively estimate (bound) these types of quantities -- without being overly conservative -- when only a few samples of a random quantity are available from model predictions or replicate experiments. This report examines a class of related sparse-data uncertainty representation and inference approaches that are relatively simple, inexpensive, and effective. Tradeoffs between the methods' conservatism, reliability, and risk versus number of data samples (cost) are quantified with multi-attribute metrics use d to assess method performance for conservative estimation of two representative quantities: central 95% of response; and 10 -4 probability of exceeding a response threshold in a tail of the distribution. Each method's performance is characterized with 10,000 random trials on a large number of diverse and challenging distributions. The best method and number of samples to use in a given circumstance depends on the uncertainty quantity to be estimated, the PDF character, and the desired reliability of bounding the true value. On the basis of this large data base and study, a strategy is proposed for selecting the method and number of samples for attaining reasonable credibility levels in bounding these types of quantities when sparse samples of random variables or functions are available from experiments or simulations.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2018

A simple model of the effect of ocean ventilation on ocean heat uptake

Presentation includes slides on Earth System Models vs. Simple Climate Models; A Popular SCM: Energy Balance Model of Anomalies; On calibrating against one ESM experiment, the SCM correctly captures that ESM's surface warming response with other forcings; Multi-Model Analysis: Multiple ESMs, Single SCM; Posterior Distributions of ECS; However In Excess of 90% of TOA Energy Imbalance is Sequestered in the World Oceans; Heat Storage in the Two Layer Model; Heat Storage in the Two Layer Model; Including TOA Rad. Imbalance and Ocean Heat in Calibration Improves Repr., but Significant Errors Persist; Improved Vertical Resolution Does Not Fix Problem; A Series of Expts. Confirms That Anomaly-Diffusing Models Cannot Properly Represent Ocean Heat Uptake; Physics of the Thermocline; Outcropping Isopycnals and Horizontally-Averaged Layers; Local interactions between outcropping isopycnals leads to non-local interactions between horizontally-averaged layers; Both Surface Warming and Ocean Heat are Well Represented With Just 4 Layers; A Series of Expts. Confirms That When Non-Local Interactions are Allowed, the SCMs Can Represent Both Surface Warming and Ocean Heat Uptake; and Summary and Conclusions.

58 GEOSCIENCES↗
DOE OSTI2018

Survey of DAKOTA's V&V Capabilities in the Simulation of Residual Stresses in a Simple Composite Structure

Process-induced residual stresses occur in composite structures composed of dissimilar materials. As these residual stresses can result in fracture, their consideration when designing composite parts is necessary. However, the experimental determination of residual stresses in prototype parts can be time and cost prohibitive. Alternatively, it is possible for computational tools to predict potential residual stresses. Therefore, a process modeling methodology was developed and implemented into Sandia National Laboratories' SIERRA/SolidMechanics code. This method can be used to predict the process-induced stresses in any composite structure, regardless of material composition or geometric complexity. However, to develop confidence in these predictions, they must be rigorously validated. Specifically, sensitivity studies should be completed to define which model parameters are critical to the residual stress predictions. Then, the uncertainty associated with those critical parameters should be quantified and processed through the model to develop stress-state predictions encompassing the most important sources of physical variability. Numerous sensitivity analysis and uncertainty quantification methods exist, each offering specific strengths and weaknesses. Therefore, the objective of this study is to compare the performance of several accepted sensitivity analysis and uncertainty quantification methods during the manufacturing process simulation of a composite structure. The examined methods include simple sampling techniques as well as more sophisticated surrogate approaches. The computational costs are assessed for each of the examined methods, and the results of the study indicate that the surrogate approaches are the most computationally efficient validation methods and are ideal for future residual stress investigations.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Microgrid Design Toolkit (MDT) Simple Use Case Example for Islanded Mode Optimization Software (V.1.1)

This simple Microgrid Design Too lkit (MDT) use case will provide you an example of a basic microgrid design. It will introduce basic principles of using the MDT islanded mode optimization by modifying a baseline microgrid design and performing an analysis of the results. Please reference the MDT User Guide (SAND2O15-85930) for detailed instructions on how to use the tool.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2019

Simple formula for surface roughness wakes

For energy recovery linacs (ERLs) the energy spread induced by wake- fields grows throughout acceleration and decelleration. Too much fractional momentum spread at low energy will complicate beam transport. This note uses some analytical results and a simple model of surface roughness correlation functions to obtain a wakefield formula that is very fast and easy to compute.

43 PARTICLE ACCELERATORS↗
DOE OSTI2019

A Simple Hydride Model for Cerium Ejecta Particles

Cerium ejecta particles form after a shock wave impacts a cerium plate with a known roughness or prescribed surface perturbation. When these particles are ejected into hydrogen or deuterium gas the material reacts exothermically and raises the temperature of the particle relative to the gas. A simple model is developed, assuming that the particle remains intact and spherical, to capture the heat and mass transfer that occurs during this process. Model performance is evaluated by comparing with cerium ejecta experiments where the particles are ejected into deuterium gas at initial pressures of 4 and 8 atm. Overall, the model is able to capture the approximately 400 K increase in particle temperature above the surrounding gas temperature.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Microgrid Design Toolkit (MDT) Simple Use Case Example for Islanded Mode Optimization Software (V1.2)

This simple Microgrid Design Toolkit ( MDT ) use case will provide you an example of a basic microgrid design. It will introduce basic principles of using the MDT islanded mode optimization by modifying a baseline microgrid design and performing an analysis of the results . Please reference the MDT User Guide (SAND201-9374) for detailed instructions on how to use the tool.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2017

Microgrid Design Toolkit (MDT) Simple Use Case Example for the Microgrid Sizing Capability Software (V1.2)

This simple Microgrid Design Toolkit (MDT) use case will provide you an example of performing microgrid sizing by identifying the types and quantities of technology to be purchased for use in a microgrid. It will introduce basic principles of using the MDT microgrid sizing capability by comparing the results of two microgrids in two different markets. Please reference the MDT User Guide (SAND2017-9374) for detailed instructions on how to use the tool.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2020

A simple hydride model for cerium ejecta particles

Cerium ejecta particles form after a shock wave impacts a cerium plate with a known roughness or prescribed surface perturbation. When these particles are ejected into hydrogen or deuterium gas the material reacts exothermically and raises the temperature of the particle relative to the gas. A simple model is developed, assuming that the particle remains intact and spherical, to capture the heat and mass transfer that occurs during this process. Model performance is evaluated by comparing with cerium ejecta experiments where the particles are ejected into deuterium gas at initial pressures of 4 and 8 atm. Overall, the model is able to capture the approximately 400 K increase in particle temperature above the surrounding gas temperature.

36 MATERIALS SCIENCE↗