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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Performance Evaluation and Parameter Identification on DROID III

The DROID III project consisted of two main parts. The former, performance evaluation, focused on the performance characteristics of the aircraft such as lift to drag ratio, thrust required for level flight, and rate of climb. The latter, parameter identification, focused on finding the aerodynamic coefficients for the aircraft using a system that creates a mathematical model to match the flight data of doublet maneuvers and the aircraft s response. Both portions of the project called for flight testing and that data is now available on account of this project. The conclusion of the project is that the performance evaluation data is well-within desired standards but could be improved with a thrust model, and that parameter identification is still in need of more data processing but seems to produce reasonable results thus far.

Plumb, Julianna J.↗
DOE OSTI2020

Performance evaluation of surface riding wave energy converter with linear electric generator

In this work, we devised a new WEC (wave energy converter) called SR-WEC (Surface Riding WEC). The SR-WEC consists of two bodies: the outer cylinder with an armature assembly (body #1) and a magnet assembly (body #2) sliding inside the armature. For the SR-WEC, the relative sliding displacement and velocity are caused by gravity acceleration and the outer cylinder's motions, and they lead to electrical power generation. To evaluate its performance, a numerical simulation tool was developed, which solves the fully-coupled floater-mooring-generator dynamics. During the developing stage, the appropriate hydrodynamics model, sliding mechanics model, mooring dynamics model, and LEG (linear electric generator) electro-magnetic model were independently developed and then fully coupled in time domain to account for the cross-coupling interactions among them. Then, the developed simulation tool was verified component by component against various laboratory tests. Subsequently, systematic parametric studies were conducted with several important design parameters under various wave conditions to enhance power generation. After that, the average output power was evaluated in enlarged operational wave conditions. The present SR-WEC is particularly designed to be efficient at low sea states, which is good since they cover the majority of typical annual sea states.

42 ENGINEERING↗
NASA NTRS2004

Real-Time Point Positioning Performance Evaluation of Single-Frequency Receivers Using NASA's Global Differential GPS System

This paper evaluates the performance of a single-frequency receiver using the 1-Hz differential corrections as provided by NASA's global differential GPS system. While the dual-frequency user has the ability to eliminate the ionosphere error by taking a linear combination of observables, the single-frequency user must remove or calibrate this error by other means. To remove the ionosphere error we take advantage of the fact that the magnitude of the group delay in range observable and the carrier phase advance have the same magnitude but are opposite in sign. A way to calibrate this error is to use a real-time database of grid points computed by JPL's RTI (Real-Time Ionosphere) software. In both cases we evaluate the positional accuracy of a kinematic carrier phase based point positioning method on a global extent.

internet-based global differential GPS (IGDG)↗
DOE OSTI2023

Aviation Mission Profile Performance Evaluation in a High Specific Power Surface Permanent Magnet Machine with Additively Manufactured Coils and Integrated Heat Pipes

The purpose of this paper is to accurately evaluate the performance and overall efficiency of an electrical machine driving a propeller (as a part of a hybrid or electric propulsion system) during the flight mission profile using electromagnetic-thermal simulations. The study focuses on a 250 kW, 5000 rpm, 1.25 kHz, 36/30 slot/pole surface permanent magnet (SPM) machine with additively manufactured (AM) hollow conductors and integrated heat pipes (HP). The machine drive parameters (frequency, and current) are tuned to maximize the efficiency for a given flight cycle, while providing the highest specific power (SP) during takeoff. Afterward using Multiphysics simulations, the transient thermal behavior of the machine is studied and temperature profile for different parts of the machine is extracted. Finally, steady-state temperatures during cruising are estimated and overall efficiency is re-evaluated.

additive manufacturing↗
NASA NTRS1982

SEASAT SAR performance evaluation study

The performance of the SEASAT synthetic aperture radar (SAR) sensor was evaluated using data processed by the MDA digital processor. Two particular aspects are considered the location accuracy of image data, and the calibration of the measured backscatter amplitude of a set of corner reflectors. The image location accuracy was assessed by selecting identifiable targets in several scenes, converting their image location to UTM coordinates, and comparing the results to map sheets. The error standard deviation is measured to be approximately 30 meters. The amplitude was calibrated by measuring the responses of the Goldstone corner reflector array and comparing the results to theoretical values. A linear regression of the measured against theoretical values results in a slope of 0.954 with a correlation coefficient of 0.970.

Source record↗
DOE OSTI2016

Performance evaluation of a continuous-flow bioanode microbial electrolysis cell fed with furanic and phenolic compounds

Furanic and phenolic compounds, formed during the pretreatment of lignocellulosic biomass, are problematic byproducts in down-stream biofuel processes. A microbial electrolysis cell (MEC) is an alternative technology to handle furanic and phenolic compounds and produce renewable hydrogen (H 2 ). In this study, we evaluated the performance of a continuous-flow bioanode MEC fed with furanic and phenolic compounds at different operating conditions. All hydraulic retention times (HRTs) tested (6-24 h) resulted in complete transformation of the parent compounds at an organic loading rate (OLR) of 0.2g L -1 per d and applied voltage of 0.6 V. Increasing the OLR to 0.8 g L -1 per d at an HRT of 6h resulted in an increased H 2 production rate from 0.07 to 0.14 L L anode 1 per d, but an OLR of 3.2 g L -1 per d did not lead to a higher H 2 production rate. Significant methane production was observed at an OLR of 3.2 g L -1 per d. The lack of increased H 2 production at the highest OLR tested was due to a limited rate of exoelectrogenesis but not fermentation, evidenced by the accumulation of high acetate levels and higher growth of fermenters and methanogens over exoelectrogens. Increasing applied voltage from 0.6 to 1.0V at an OLR of 3.2 g L -1 per d and HRT of 6h enhanced exoelectrogenesis and resulted in a 1.7-fold increase of H 2 production. Under all operating conditions, more than 90% of the biomass was biofilm-associated. Lastly, the present study provides new insights into the performance of continuous-flow bioelectrochemical systems fed with complex waste streams resulting from the pretreatment of lignocellulosic biomass.

09 BIOMASS FUELS↗
DOE OSTI2025

Comparative Performance Evaluation of Large Language Models for Extracting Molecular Interactions and Pathway Knowledge

Understanding the interactions and regulatory relationships among biomolecules is essential for deciphering complex biological systems and elucidating the mechanisms behind diverse biological functions. Traditionally, the collection of such molecular interaction data has relied on expert curation, a process that is both time-consuming and labor-intensive. To address these limitations, this study explores the use of large language models (LLMs) to automate the genome-scale extraction of molecular interaction knowledge. Here, we evaluate the performance of various LLMs on key biological tasks, including the identification of protein-protein interactions, detection of genes associated with pathways influenced by low-dose radiation, and inference of gene regulatory relationships. Our findings demonstrate that larger LLMs tend to perform better, particularly in extracting intricate gene and protein interactions. Despite their strengths, these models face challenges in recognizing functionally diverse gene groups and highly correlated regulatory relationships. Through a comprehensive analysis using established molecular interaction and pathway databases, we show that LLMs possess the potential to identify relevant biomolecules and predict their interactions, offering valuable insights and marking a significant step toward AI-driven biological knowledge discovery.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗
DOE OSTI2016

Performance evaluation of a high resolution dedicated breast PET scanner

Purpose: Early stage breast cancers may not be visible on a whole-body PET scan. To overcome whole-body PET limitations, several dedicated breast positron emission tomography (DbPET) systems have emerged nowadays aiming to improve spatial resolution. In this work the authors evaluate the performance of a high resolution dedicated breast PET scanner (Mammi-PET, Oncovision). Methods: Global status, uniformity, sensitivity, energy, and spatial resolution were measured. Spheres of different sizes (2.5, 4, 5, and 6 mm diameter) and various 18 fluorodeoxyglucose ({sup 18}F-FDG) activity concentrations were randomly inserted in a gelatine breast phantom developed at our institution. Several lesion-to-background ratios (LBR) were simulated, 5:1, 10:1, 20:1, 30:1, and 50:1. Images were reconstructed using different voxel sizes. The ability of experienced reporters to detect spheres was tested as a function of acquisition time, LBR, sphere size, and matrix reconstruction voxel size. For comparison, phantoms were scanned in the DbPET camera and in a whole body PET (WB-PET). Two patients who just underwent WB-PET/CT exams were imaged with the DbPET system and the images were compared. Results: The measured absolute peak sensitivity was 2.0%. The energy resolution was 24.0% ± 1%. The integral and differential uniformity were 10% and 6% in the total field of view (FOV) and 9% and 5% in the central FOV, respectively. The measured spatial resolution was 2.0, 1.9, and 1.7 mm in the radial, tangential, and axial directions. The system exhibited very good detectability for spheres ≥4 mm and LBR ≥10 with a sphere detection of 100% when acquisition time was set >3 min/bed. For LBR = 5 and acquisition time of 7 min the detectability was 100% for spheres of 6 mm and 75% for spheres of 5, 4, and 2.5 mm. Lesion WB-PET detectability was only comparable to the DbPET camera for lesion sizes ≥5 mm when acquisition time was >3 min and LBR > 10. Conclusions: The DbPET has a good performance for its clinical use and shows an improved resolution and lesion detectability of small lesions compared to WB-PET.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2012

Performance Evaluation of HYCOM-GOM for Hydrokinetic Resource Assessment in the Florida Strait

The U.S. Department of Energy (DoE) is assessing and mapping the potential off-shore ocean current hydrokinetic energy resources along the U.S. coastline, excluding tidal currents, to facilitate market penetration of water power technologies. This resource assessment includes information on the temporal and three-dimensional spatial distribution of the daily averaged power density, and the overall theoretical hydrokinetic energy production, based on modeled historical simulations spanning a 7-year period of record using HYCOM-GOM, an ocean current observation assimilation model that generates a spatially distributed three-dimensional representation of daily averaged horizontal current magnitude and direction time series from which power density time series and their statistics can be derived. This study ascertains the deviation of HYCOM-GOM outputs, including transport (flow) and power density, from outputs based on three independent observation sources to evaluate HYCOM-GOM performance. The three independent data sources include NOAA s submarine cable data of transport, ADCP data at a high power density location, and HF radar data in the high power density region of the Florida Strait. Comparisons with these three independent observation sets indicate discrepancies with HYCOM model outputs, but overall indicate that the HYCOM-GOM model can provide an adequate assessment of the ocean current hydrokinetic resource in high power density regions like the Florida Strait. Additional independent observational data, in particular stationary ADCP measurements, would be useful for expanding this model performance evaluation study. ADCP measurements are rare in ocean environments not influenced by tides, and limited to one location in the Florida Strait. HF radar data, although providing great spatial coverage, is limited to surface currents only.

ADCP↗
DOE OSTI2014

Thermal Performance Evaluation of Walls with Gas Filled Panel Insulation

Gas filled insulation panels (GFP) are very light weight and compact (when uninflated) advanced insulation products. GFPs consist of multiple layers of thin, low emittance (low-e) metalized aluminum. When expanded, the internal, low-e aluminum layers form a honeycomb structure. These baffled polymer chambers are enveloped by a sealed barrier and filled with either air or a low-conductivity gas. The sealed exterior aluminum foil barrier films provide thermal resistance, flammability protection, and properties to contain air or a low conductivity inert gas. This product was initially developed with a grant from the U.S. Department of Energy. The unexpanded product is nearly flat for easy storage and transport. Therefore, transportation volume and weight of the GFP to fill unit volume of wall cavity is much smaller compared to that of other conventional insulation products. This feature makes this product appealing to use at Army Contingency Basing, when transportation cost is significant compared to the cost of materials. The objective of this study is to evaluate thermal performance of walls, similar to those used at typical Barracks Hut (B-Hut) hard shelters, when GFPs are used in the wall cavities. Oak Ridge National Laboratory (ORNL) tested performance of the wall in the rotatable guarded hotbox (RGHB) according to the ASTM C 1363 standard test method.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2015

Performance Evaluation of Mineral Additive-free Perfluoropolymer Nanocomposite O-ring in Simulated Geothermal Environments of 300C

The objective of this research was to evaluate the performance of O-rings made with a mineral additive-free perfluoropolymer (FFKM) nanocomposite in mitigating irremovable silica- and silicate-scaling, inhibiting oxidative reactions, minimizing the changes in mechanical behaviors, and maintaining the integrity of O-rings after their exposure to the five different simulated geothermal environments at 300°C: 1) 0.01N sodium metasilicate (SMS)-laden non-aerated (NR2R R(g) Rsaturated) steam-cooling cycles; 2) 0.01N SMS-laden aerated steam-cooling cycles; 3) water-based drilling fluid; 4) COR2R-rich geo-brine fluid; and, 5) heat-cool water quenching cycles (thermal shock). All the thermochemical environments 1 to 4 were carried out under a pressure of 8.3 MPs.

15 GEOTHERMAL ENERGY↗
DOE OSTI2019

Bayesian performance evaluation of evapotranspiration models based on eddy covariance systems in an arid region

Abstract. Evapotranspiration (ET) is a major component of the land surface processinvolved in energy fluxes and energy balance, especially in the hydrologicalcycle of agricultural ecosystems. While many models have been developed aspowerful tools to simulate ET, there is no agreement on which model bestdescribes the loss of water to the atmosphere. This study focuses on twoaspects, evaluating the performance of four widely used ET models andidentifying parameters, and the physical mechanisms that havesignificant impacts on the model performance. The four tested models arethe Shuttleworth–Wallace (SW) model, Penman–Monteith (PM) model,Priestley–Taylor and Flint–Childs (PT–FC) model, and advection–aridity (AA)model. By incorporating the mathematically rigorous thermodynamicintegration algorithm, the Bayesian model evidence (BME) approach is adoptedto select the optimal model with half-hourly ET observations obtained at aspring maize field in an arid region. Our results reveal that the SW model has thebest performance, and the extinction coefficient is not merely partitioningthe total available energy into the canopy and surface but also includingthe energy imbalance correction. The extinction coefficient is wellconstrained in the SW model and poorly constrained in the PM model but notconsidered in PT–FC and AA models. This is one of the main reasons that theSW model outperforms the other models. Meanwhile, the good fitting of SWmodel to observations can counterbalance its higher complexity. In addition,the detailed analysis of the discrepancies between observations and modelsimulations during the crop growth season indicate that explicit treatmentof energy imbalance and energy interaction will be the primary way offurther improving ET model performance.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1972

Skylab experiment performance evaluation manual

A series of preparation analyses used for evaluating the performance of the Skylab corollary experiments under preflight, in-flight, and postflight conditions is given. Experiment continegency plan work-around procedure and malfunction analyses are presented in order to assist in making the experiment operationally succesful.

Meyers, J. E.↗
NASA NTRS1972

Skylab experimental performance evaluation manual. Appendix O: Experiment T002 manual navigation sightings (MSFC)

A series of analyses for Experiment T002, Navigation Sightings (MSFC), to be used for evaluating the performance of the Skylab corollary experiments under preflight, inflight, and post-flight conditions are presented. Experiment contingency plan workaround procedure and malfunction analyses are presented in order to assist in making the experiment operationally successful.

Purushotham, K. S.↗
NASA NTRS1972

Skylab experiment performance evaluation manual. Appendix R: Experiment T020 foot controlled maneuvering unit (MSFC)

A series of analyses for experiment T020, foot controlled maneuvering unit (MSFC), to be used for evaluating the performance of the Skylab corollary experiments under preflight, inflight and post-flight conditions is reported. Experiment contingency plan procedure and malfunction analyses are presented in order to assist in making the experiment operationally successful.

Tonetti, B. B.↗
NASA NTRS1972

Skylab experiment performance evaluation manual. Appendix P: Experiment T003 inflight aerosol analysis (DOT/MSFC)

A series of analyses is presented for experiment T003, inflight aerosol analysis, to be used for evaluating the performance of the Skylab corollary experiments under preflight, inflight, and post-flight conditions. Experiment contingency plan workaround procedure and malfunction analyses are presented in order to assist in making the experiment operationally successful.

Purushotham, K. S.↗